Disease risk stratification will be based on the cytogenetic and molecular features of the tumor cells, response to first induction, presence of secondary or therapy related disease, white blood cell (WBC) at diagnosis and measurable residual disease. - Patients with favorable cytogenetics and no unfavorable molecular changes show good response to chemo-immunotherapy and in the majority of cases will enter a second remission if relapse occurs. Patients with t(8;21) or inv(16) / t(16;16) without evidence of a KIT mutation should undergo allogeneic stem cell transplant in CR2. - Patients with a normal karyotype who are FLT3 ITD negative and either NPM1 mutation positive or CEBP biallelic mutation positive are expected to have a favorable outcome to chemoimmunotherapy and should be offered an allogeneic stem cell transplant in CR2.# 
- Patients in the intermediate cytogenetic risk group may be offered a transplant from a matched sibling or a matched unrelated donor in CR1. This includes patients with a normal karyotype as well as non-informative cytogenetic changes. Patients with t(8;21) or inv(16) / t (16;16) and a KIT mutation appear to fall into this risk group. Patients with FLT3 ITD at low allelic ratio and with FLT3 TKD mutation also appear to fall into this risk group.
- Patients with high-risk features will likely not be salvageable at relapse and should be offered transplant in first complete remission. This includes high-risk cytogenetics, those with a normal karyotype who are FLT3 ITD positive, various molecular findings on NGS, those requiring more than one chemotherapy cycle to achieve a complete remission, as well as those with secondary or therapy related disease or measurable residual disease after two cycles of chemotherapy.
- Patients who relapse after conventional chemotherapy should undergo stem cell transplantation in CR2.
- It is preferable for patients to be in complete remission (defined as fewer than 5% blasts and no active extra-medullary disease) at the time of transplantation. Patients with untreated or refractory CNS disease or with circulating blasts are not eligible for transplantation.
- Patients should receive at least one cycle of post-remission therapy prior to transplantation if transplantation cannot occur within 4 weeks of the complete remission being achieved.

# Background
Risk stratification in AML has traditionally relied on patient and disease characteristics at diagnosis (chiefly: age, cytogenetics, white blood cell count at diagnosis and the presence of an antecedent hematological disorder or therapy related disease) and on the response to induction chemotherapy. While patients in favorable risk categories may enjoy long-term disease free survival, AML may be virtually incurable with conventional treatment in patients with high-risk features and those with poor response to chemotherapy. Recently, the interaction of molecular abnormalities with cytogenetic risk groups has been defined. Risk-adapted therapy attempts to avoid exposing favorable-risk patients to the morbidity and mortality risks of stem cell transplant while directing high-risk patients to up-front transplant in order to minimize relapse risk early in the course of therapy. Measurable residual disease (MRD) after induction and/or consolidation chemotherapy is also becoming more reliably prognostic.

# Prognosis
Cytogenetic Risk Groups Abbreviations: CR = complete remission; DFS = disease-free survival.

# Molecular Risk Groups
Patients with normal cytogenetics make up the largest group of patients with AML, yet they show significant variability in outcomes with standard treatment. The likely explanation for this finding is the influence of molecular abnormalities that go undetected by standard cytogenetics. Among these abnormalities, mutations of NPM-1 and CEBPA are associated with significantly better overall survival (OS) compared to patients with the wild-type loci. Mutations to FLT-3 confer inferior OS on patients who harbor these mutations. Similarly, while cytogenetic abnormalities that disrupt Core Binding Factor (t (8;21) and inv (16)) are typically associated with favorable outcomes with conventional therapies, the presence of mutations of c-Kit in these disorders confers a significantly shorter OS and a marked increase in the cumulative incidence of relapse. Patients with these abnormalities should be considered for early allogeneic stem cell transplant. Next-generation sequencing is now done routinely in transplant eligible patients and allows for the detection of many other known mutations of potential clinical significance.
RUNX1 and AXSL1 mutations, each occurring in 10-15% of AML patients, have each been associated with adverse prognosis, particularly when occurring in intermediate risk disease, and these patients appear to benefit from transplant in CR1. Similarly, TP53 and splicing factor mutations (e.g. SRSF2) have also been associated with independently adverse prognosis. RUNX1, ASXL1 and TP53 mutated disease have been assigned to the adverse risk group in the 2017 ELN classification, except when they occur in otherwise ELN favorable risk disease. Therefore, this mutational information can be helpful in risk stratification. With respect to other mutations (e.g. DNMT3A, IDH, TET2) the data regarding prognosis are less clear.   5 adds measurable residual disease after 2 cycles of chemotherapy (e.g., 1 induction and 1 consolidation) and other prognostic factors to the cytogenetic and molecular risk stratification to further help with decision on allogeneic stem cell transplantation in first complete remission. Abbreviations: CA = cytogenetic abnormalities; CBF = core binding factor; CN = cytogenetically normal; CRe = early complete remission; EBMT = European Group for Blood and Marrow Transplantation; HCT-CI= hematopoietic cell transplantation comorbidity index; ITD = internal tandem duplication; MK = monosomal karyotype; NA = not applicable; NRM = non-relapse mortality; -X -Y = deleted X or Y chromosome. 

# Combined Cytogenetic and Molecular Risk Groups

# Treatment
If CR has been achieved further therapy is necessary for potential cure. The nature of consolidation therapy must be individualized for each patient based on a risk analysis of the risk of relapse of the AML versus the risk of the proposed consolidation therapy. This will depend on prognostic features of the leukemia, response to therapy, performance status and type of hematopoietic stem cell donor available. High dose Ara-c (HiDAC) is the mainstay of consolidation chemotherapy as there has been shown to be a dose intensity effect to cytarabine suggesting that HiDAC is necessary in induction or consolidation. Additional agents such as FLT3 inhibitors or gemtuzumab ozogamicin are added as indicated and CPX-351 can replace HiDAC in the appropriate patients. Generally at least one cycle is administered in all patients if only to allow for planning of an allogeneic stem cell transplant although the absolute need for this is controversial. Autologous stem cell transplantation shows some superiority in event-free survival over chemotherapy alone for consolidation, however is not routinely recommended unless a donor is not available.
- Favorable risk patients: In patients with AML with t(8;21), inv 16 or isolated NPM1 mutation data suggests that provided there are no additional risk factors multiple cycles of HiDAC provide higher overall survival than lower doses of cytarabine or stem cell transplant. Our recommendation is 2-4 cycles of HiDAC post induction chemotherapy accompanied by gemtuzumab ozogamicin for the first two cycles.
- Intermediate risk patients: HiDAC has been shown to be preferable to lower dose cytarabine in this cytogenetic group as well but its superiority over stem cell transplantation has not been established. It is generally recognized that an allogeneic stem cell transplant provides a decreased relapse rate at a cost of increased treatment related mortality when compared to consolidation chemotherapy or autologous transplantation. The transplant related mortality gap between match related and unrelated donors has been shown to be significantly reduced in recent years. A suitable hematopoietic stem cell donor should be sought and myeloablative stem cell transplantation should proceed as soon as possible, ideally after one cycle of HiDAC based on a risk/benefit analysis.
- High risk patients: All efforts should be undertaken to find a suitable donor for eligible high-risk patients. During that time the patient should receive ongoing cycles of HiDAC chemotherapy up to a total of 4 cycles or CPX-351 up to 2 cycles. The patient should proceed to allogeneic stem cell transplantation as soon as a donor is identified. 

# Summary
- The search for a donor should be undertaken for all patients, including those with standard risk disease until it has been proven that they can tolerate the intensification portion of the chemotherapy protocol. - Transplantation in first complete remission will be offered to patients who meet other eligibility criteria and who have any one of the following: o A high white blood cell count at diagnosis (pre-B cell phenotype > 30, pre-T cell phenotype > 100). o Failure to enter complete measurable residual disease negative remission within 28 days of starting induction chemotherapy. o Complex (>5 abnormalities), low hypodiploid (30-39 chromosomes) or near triploid (66-79 chromosomes) karyotypes. o t(8;14), KMT2A gene rearrangements or IKZF1 mutations. o Philadelphia-like disease. o Intolerance of post-induction chemotherapy such that less than 80% of scheduled chemotherapy is likely to be delivered. - Transplantation in first complete remission should be considered in patients with Philadelphia chromosome positivity who do not achieve early MRD clearance or who are unable to tolerate planned chemotherapy - Patients without documented CNS disease should receive at least four doses of intrathecal chemotherapy for CNS prophylaxis prior to transplant. - Patients should be in remission (defined as fewer than 5% blasts in a normocellular bone marrow and no active extramedullary disease or circulating blasts) at the time of transplantation. - BCR-ABL will be monitored post-transplant and TKI therapy re-instituted upon any evidence of molecular positivity. TKI prophylaxis should be considered for those with high-risk disease at the time of transplant (see below for details). - Stem cell transplantation should be offered to all transplant-eligible patients with recurrent ALL, a suitable donor and meeting general eligibility criteria (including remission status) for transplantation. - CAR-T therapy with Tisagenlecleucel may be offered in the setting of relapsed or refractory disease.

# Background
The age-adjusted incidence rate of ALL in the US is 1.6 per 100,000 individuals per year, with approximately 6070 new cases and 1430 deaths estimated in 2013 1,2 . The median age at diagnosis is 2 www.ahs.ca/guru BMT Standard Practice Manual Last Reviewed: October 11, 2022 Effective: October 11, 2022 14 years; 60% of patients are diagnosed at younger than 20 years, whereas 24% are diagnosed at 45 years or older 2 . The potential years of life lost due to leukemia in Canada has been reported to be 37,000 3 . The large number of years lost for a relatively uncommon diagnosis reflects the occurrence of leukemia among very young individuals and the high mortality these patients experience.

# Chemotherapy
With current treatment regimens, the cure rate among children with ALL is approximately 80-90% 4 . The long-term prognosis for adults with ALL treated with conventional chemotherapy regimens, however, remain poor, with cure rates of only 30 to 40%  . This reflects the greater tendency for older individuals to have adverse chromosomal markers (notably t (9; 22)) and other unfavorable prognostic indicators (high white blood cell (WBC) count, longer time to complete response). Multidrug chemotherapy regimens have been the standard approach to treatment of adults with ALL. Such regimens generally consist of 4-or 5-drug induction protocols followed by intensive re-induction, consolidation or intensification to address residual disease. These regimens also feature CNS prophylaxis in the form of whole brain radiotherapy or intrathecal chemotherapy and prolonged antimetabolite-based maintenance, as has been used successfully in management of pediatric cases.
In recent years, a growing body of data has shown that, at least for late adolescents and young adults (defined variably up to 40 years of age), treatment with pediatric-based protocols produces superior outcomes to the regimens standardly used in adults  . Canadian data has shown that a pediatric approach can safely be extended to adults up to the age of 60 with only minor modifications 18 . This protocol is heavily dependent on L-Asparaginase in intensification and has been shown to have the best outcomes if 80% of L-Asparaginase doses can be delivered; this has been shown to be possible in 80% of patients. Meaningful comparisons of this strategy with early transplantation have yet to be published.
Many novel therapies are being studied in the management of ALL and may affect the need for or the outcome of stem cell transplantation in the future. These include Blinatumomab 19 , Inotuzumab 20 , the addition of Rituximab to chemotherapy 21 and CAR-T cell therapy 22 .
CNS prophylaxis in the form of, intrathecal chemotherapy and/or high dose systemic chemotherapy has been shown to be necessary throughout chemotherapy and prior to stem cell transplantation.

# Risk Stratification in ALL
Risk stratification in adult ALL has been based on disease (molecular findings, cytogenetics, WBC at diagnosis, response to treatment) and patient (chiefly age) factors. Leukemic blasts with T-cell or mature B-cell immunophenotype or the presence of a mediastinal mass are associated with overall improved survival. Blasts bearing the Philadelphia chromosome or t(4; 11), older patient age, high WBC or poor response to chemotherapy (> 4 weeks to complete response) portend a poor outcome The use of minimal residual disease (MRD) has been well-established in children with ALL. Studies in adults have also shown the strong correlation between MRD and risks for relapse, and the prognostic significance of MRD measurements during and after initial induction therapy. How to ultimately use MRD in deciding on the need for hematopoietic stem cell transplantation has not yet been fully established but is likely to play a role, particularly when tested after induction  .

# Hematopoietic Stem Cell Transplant (HSCT)

# Transplantation in First Complete Remission
At any stage of disease, allogeneic bone marrow transplantation (BMT) results in lower relapse risk than standard chemotherapy. Many investigators have been unable to demonstrate an improvement in overall survival using this strategy as a result of high treatment-related mortality in this modality. Investigators at Princess Margaret Hospital reported their experience with a policy of allogeneic HSCT for all patients with ALL younger than 55 who had a related donor. Patients with Philadelphiachromosome positive ALL were offered transplantation from a matched, unrelated donor if one was available. This strategy resulted in 3-year EFS of 40% for patients with donors and 39% for patients without. This strategy of universal allogeneic stem cell transplantation in ALL failed to improve outcome of patients with Philadelphia-negative ALL, while outcome was equivalent among patients with Philadelphia-positive disease.
In other cases the difference between allogeneic blood cell transplantation (BCT) and conventional chemotherapy has been more pronounced. The French LALA '87 trial demonstrated improved overall survival among high-risk patients undergoing alloHSCT in CR1 (10-year OS 44%), compared with those who received chemotherapy or autologous BCT (10-year OS 11%). A similar impact on survival Transplantation in first complete remission will be offered to patients who meet other eligibility criteria and who have any one of the following: o A high white blood cell count at diagnosis (pre-B cell phenotype > 30, pre-T cell phenotype > 100). o Failure to enter complete measurable residual disease negative remission within 28 days of starting induction chemotherapy. o Complex (>5 abnormalities), low hypodiploid (30-39 chromosomes) or near triploid (66-79 chromosomes) karyotypes. o Philadelphia chromosome (or BCR-Abl), t(8;14), KMT2A gene rearrangements or IKZF1 mutations. o Philadelphia-like disease. o Intolerance of post-induction chemotherapy such that less than 80% of scheduled chemotherapy is likely to be delivered.

# Philadelphia-positive Acute Lymphoblastic Leukemia
Twenty to forty percent of transplant-eligible adults with ALL will be found to have the Philadelphia chromosome as a sole or contributing cytogenetic abnormality. Patients with this abnormality tend to have other adverse prognostic features and have the lowest CR rate (< 65%) and shortest remission durations (median remission duration ~ 9 months) with conventional therapy. Overall survival is between 0 -16%. In single-institution, non-randomized studies, leukemia-free survival after allogeneic BCT for Philadelphia-positive ALL is 30-40%. 

# CAR-T Therapy
Tisagenlecleucel is indicated in Canada for the treatment of relapsed or refractory acute lymphoblastic leukemia in patients under the age of 26. This indication is based partly on the results of a single-cohort, multi-center phase II trial (ELIANA) conducted by Maude et al 54 . In this study, children and young adults with relapsed or refractory CD19+ B-cell ALL received a single infusion of tisagenlecleucel after lymphodepleting chemotherapy. The primary end point, the overall remission rate at 3 months, was 82%, with all responding patients negative for MRD by flow cytometry. Eventfree and overall survival were 50% and 76% at one year. Cytokine release syndrome occurred in 77% of patients, with tocilizumab required in 48%. Neurological events occurred in 40%. There were significant improvements in patient-reported outcomes (PedsQL and EQ-5D) three months after treatment 55 . Real world evidence in 255 patients with relapsed or refractory ALL further supports the use of tisagenlecleucel in this context. In this report twelve-month EFS and OS were 52.4% and 77.2% 56 .
Brexucabtagene autoleucel has been approved by the FDA for use in adults with relapsed or refractory ALL based on the ZUMA-3 phase II study. This showed that in patients aged 28-52 with a median followup of 16.4 months, 39 patients had complete remission or complete remission with incomplete haematological recovery, with 31 (56%) patients reaching complete remission. Median duration of remission was 128 months, median relapse-free survival was 116 months and median overall survival was 182 months. Among responders, the median overall survival was not reached, and 38 (97%) patients had MRD negativity 57 .
As yet there is no data to guide the sequencing of CAR-T cell therapy and transplantation in this setting. 

# Summary
- All patients should have risk stratification including calculation of the Revised International Prognostic Scoring System (R-IPSS) at diagnosis.
- Patients with high (>4.5 to 6 points) or very high (>6 points) R-IPSS should be offered HCT if they are transplant-eligible.
- Patients with intermediate (>3 to 4.5 points) R-IPSS with symptomatic cytopenias or evidence of disease progression, who are transplant-eligible, can be considered for allogeneic HCT; with consideration of patient values and discussion around risks of transplant compared to the underlying disease.
- Sibling typing should be initiated at the earliest opportunity for all transplant-eligible patients.
- Disease control as a bridge to transplant with induction chemotherapy (consider if blasts >10% and no TP53 mutation and/or adverse cytogenetic profile) or hypomethylating agents such as azacitidine should be considered for patients with higher risk disease or elevated blast counts at presentation. The optimal therapy in this setting is not clear.
- Consider minimizing iron overload pretransplant to minimize the adverse effects of iron overload on treatment-related mortality.
- Myeloablative conditioning is preferred over non-myeloblative conditioning in patients who are fit to improve patient outcomes. Our standard conditioning is myeloablative busulfan + fludarabine + 4Gy TBI (see Conditioning chapter).
- Patients under the age of 40 or with an appropriate family history should be screened for congenital causes of MDS (i.e. Fanconi, dyskeratosis congenita). Appropriate consideration of hereditary syndromes should be made during donor search and planning of conditioning.
- In very high-risk patients, i.e., complex karyotype and p53 mutation, alternatives to transplant should be considered.

# Background
Myelodysplastic syndromes are a heterogeneous group of related clonal stem cell disorders featuring dysplastic changes in one or more bone marrow cell lines, ineffective hematopoiesis, bone marrow failure, and often clonal evolution and/or transformation to acute leukemia. It is a disorder of the elderly, with a median age of 65-70 years at diagnosis. Allogeneic stem cell transplantation remains the only curative option; however the majority of patients are not eligible for transplantation due to age and/or comorbidity. For those who are eligible, the variable natural history of the disease and relative toxicity of transplant are important factors in the decision between supportive care, hypomethylating agents, lenalidomide, medical therapy including growth factors and allogeneic transplantation, and clinical trials. 

# Etiology
A history and physical exam should investigate for potential etiology of MDS:
- Ionizing radiation - Cytotoxic agents (i.e., alkylating agents, topoisomerase inhibitors)
- Occupational or environmental carcinogens (i.e., viruses, benzenes, heavy metals)
- Inherited disorders (i.e., Fanconi anemia) especially in consideration of related donors - Antecedent hematologic disorders (i.e. paroxysmal nocturnal hemoglobinuria, aplastic anemia).
Cytogenetic abnormalities are found in 40-70% of de novo MDS, and 95% of therapy-related MDS.    Incorporation of molecular data into the Revised IPSS score has been found to improve prognostication in MDS. Independent significant prognostic factors for survival include age, R-IPSS, EZH2, SF3B1 and TP53 3 . A linear predictive model was built which resulted in four prognostic groups (low, intermediate-1, intermediate-2 and high) with a median overall survival of 37.4, 23.2, 19.9 and 12.2 months, respectively, (P<0.001).

# Intensity of Treatment in Allogeneic Stem Cell Transplantation for MDS
Reduced intensity conditioning therapy is known to have a higher relapse rate in MDS but lower treatment-related mortality. In a retrospective study of 836 patients with MDS transplanted with an HLA matched sibling, the 3-year relapse rate was higher in patients given reduced intensity conditioning (HR 1.6, p=0.001) but a corresponding decrease in 3-year non-relapse mortality (NRM) resulted in similar progression-free survival (PFS, 33% vs. 39%) and overall survival (OS) rates (41% vs. 45%). 4 The role of treatment intensity was evaluated in a randomized multicenter phase III clinical trial comparing reduced intensity conditioning (RIC) including FluBu2 (2 days busulfan) to myeloablative conditioning regimens including our current conditioning fludarabine and busulfan without TBI. 5 The study was stopped early due to increased relapse rates with RIC 48% vs 13.5%) with a nonsignificant reduction in OS at 18 months (68% vs 78% for RIC and MAC, respectively) and a lower relapse-free survival with RIC (47% vs 68%). Notably, TRM was lower at 4.4% with RIC vs 15.8% with MAC. Outcomes with FLUBUP/TBI remain to be determined but compare favorably with these series. Local outcomes comparing the use of TBI in patients with MDS from 1999-2010 suggest improved 2-year DFS in patients given FLUBUP/TBI compared to FLUBUP alone (2-year DFS 67% vs. 41%) although with small numbers the difference is not statistically significant. The decision has been made to incorporate TBI in the transplant regimen of patients with MDS.

# Outcomes with Allogeneic Transplantation
An EBMT review of 1333 patients age >50 with high risk MDS or secondary AML who received allogeneic sibling (61%) or unrelated donor (39%) hematopoietic stem cell transplant with a myeloablative (38%) or reduced intensity conditioning (62%) regimen. 6 Of the 1333 patients, 449 (34%) were >60y of age. Four-year OS was 31%. Factors associated with higher risk of relapse include use of RIC (HR 1.44, P<0.01) and advanced disease stage at transplantation (HR, 1.51; P<0.01). Factors associated with increased non-relapse mortality include advanced disease stage at transplantation (HR, 1.43; 95% CI, 1.13 to 1.79; P = 0.01), use of an unrelated donor (P = 0.03), and RIC (HR, 0.79; 95% CI, 0.65 to 0.97; P =0 .03). The major factor associated with 4-year OS was disease stage at transplantation (HR, 1.55; P<0.01) and challenges remain in with both higher relapse rates posttransplant and higher treatment-related mortality with MDS compared to de novo AML.
A single-centre study at the University of Wisconsin describes the importance of pre-transplant disease burden (as reflected by the proportion of bone marrow blasts at transplant). Patients entering transplant with 5% blasts): relapse rates were similar for patients with >5% blasts, regardless of whether myeloablative or non-myeloablative conditioning was used (28% (CI 8-48%) vs. 50% (CI 18-82%), p=0.33).
As NGS studies become available and more information is available about disease prognostication with transplant. A Japanese study of 797 patients with MDS showed that in patients with cytogenetics and NGS testing, cox regression analysis showed approximately 70% of the hazard ratio of transplant was related to clinical factors ie performance status, comorbidities, transfusion history and 30% contributed by adverse genetic risk. 8 An especially high risk category of patients with both mutation TP53 and complex karyotype did very poorly with transplant with a median survival of 4.8 months; 38% died before day 100 and >80% within 2 years of transplant, largely due to early relapse in 60% of patients. A retrospective review of 1514 patients with MDS undergoing stem cell Bridge to HCT. The use of azacitidine provides further options for care and potentially for bridge to transplantation and cytoreduction. Several case series using azacitidine as bridge to transplantation shows this treatment is feasible; effect on transplant outcomes is being determined.  An EBMT retrospective review of 209 patients with higher risk MDS showed that outcomes at 3 years were not significantly different between patients treated with hypomethylating agents or chemotherapy prior to HCT with respect to OS (42% versus 35%), RFS (29% versus 31%), cumulative incidence of relapse (45% versus 40%), and NRM (26% versus 28%), despite younger age and a higher proportion of patients with primary refractory disease in the hypomethylating group arm. 15 In patients with very high blast counts >10% and a planned rapid progression to transplant, chemotherapy can provide a faster response and is more likely to result in a CR to help bridge to transplant, but has more toxicities. For patients with monosomy 7, del 7q, 3 chromosomal abnormalities, or mutation of TP53, hypomethylating agents are recommended over intensive chemotherapy or supportive care due to poor response rates to intensive chemotherapy in MDS patients with these features. For patients with high-risk disease, treatment is recommended as a bridge to curative therapy during transplant workup. First Line Therapy:
- First line therapy is with a tyrosine kinase inhibitor (TKI) (imatinib, dasatinib or nilotinib)
- Molecular monitoring with quantitative PCR (polymerase chain reaction) every 3 months o Cytogenetics and mutation analysis as per the chronic myeloid leukemia (CML) treatment guidelines o Assess milestones as per provincial CML treatment guidelines Subsequent Therapy:
- Adjust TKI therapy as per CML treatment guidelines for patients showing resistance or intolerance to first-line therapy, options include imatinib, dasatinib, nilotinib, bosutinib, ponatinib or asciminib - In patients on a second generation TKI showing warning signs, who experience a suboptimal response or failure and are otherwise transplant eligible, perform human leukocyte antigen (HLA) typing of patient and siblings followed by a search for a volunteer unrelated donor (VUD) if no suitable family member is identified - Transplantation should be undertaken for eligible patients who fail to meet the provincial treatment guideline milestones for response to two second generation TKIs and/or asciminib - Transplantation should be undertaken in eligible patients who are unable to tolerate tyrosine kinase inhibitors such that compliance becomes an issue - Patients found to carry the T315I mutation should receive ponatinib or asciminib during the donor search and workup periods

# Accelerated Phase
- HLA type patients and siblings and proceed with VUD search if no family match identified - Use tyrosine kinase inhibitors as a bridge to transplantation in eligible patients (may be sufficient in good prognosis groups such as clonal progression only) - Allogeneic stem cell transplantation preferred in eligible patients

# Blast Phase
- HLA type patients and siblings and proceed with VUD or alternate donor search if no family match identified - Attempt to induce CP2 prior to allogeneic stem cell transplantation with chemotherapy and TKIs - Transplantation is contraindicated in blast phase 

# Monitoring for Relapsed/Refractory CML Post Transplantation
- Quantitative peripheral blood PCR for brc/abl transcript every 3 months for 2 years then every 6 months to 5 years and then yearly to coincide with scheduled follow up appointments

# Treatment of Relapsed Disease Posttransplant
Molecular relapse or relapse in chronic phase:
- Minimize immunosuppression - Initiate therapy with a second generation TKI, preferably one not used pre-transplant if a positive PCR is detected at 6 months post-transplant or if the BCR/ABL ratio is rising prior to that - If no response toTKI a mutation analysis should be sent prior to proceeding to escalating doses of TKI Accelerated phase relapse:
- Minimize immunosuppression - Perform mutation analysis - Initiation of TKI therapy with a second generation TKI preferably one not used pre-transplant - If no response to TKI proceed to escalating doses of TKI - Consider TKI in conjunction with DLI - Consider a second transplant based on GVHD status, age, comorbidities and time from first transplant

# Blast phase relapse:
- Minimize immunosuppression - Perform mutation analysis - Re-induce chronic phase prior to a second transplant in eligible patient-overall prognosis poor; palliation is a reasonable choice Background Chronic myelogenous leukemia makes up 14% of new leukemias, with a median age of 67 years. It is associated with the Philadelphia chromosome t(9;22) and p190, p210 or p230 bcr/abl fusion proteins. The Philadelphia chromosome is found in multiple cell lineages including granulocyte, erythroid, megakaryocyte, and B lymphocyte lineages. Progression of disease is often associated with cytogenetic evolution with common additional abnormalities including +Ph, +8, i(17q) and +19. of 76% with the BuCy (busulfan + cyclophosphamide) protocol (p-value not significant). Transplantrelated mortality at 3 years was 0% compared to 24% with BuCy (p=0.03). Further data is being accrued.

# Allotransplants in the Post TKI Era
There is no evidence that transplant outcomes are worse in patients who have received prior tyrosine kinase inhibitors. A recent IBMTR analysis of 409 patients transplanted with prior imatinib exposure (9% imatinib intolerance, 37% imatinib failures, remainder planned transplants up front) and 900 patients without imatinib exposure revealed than in patients transplanted in first chronic phase, prior imatinib was associated with better overall survival, and no difference in transplant-related mortality, relapse, or leukemia-free survival. 9 This was confirmed in a matched pairs analysis. In patients with advanced CML, there was no difference between groups in transplant-related mortality, relapse, leukemia-free survival, and overall survival. No difference was seen in rates of acute GVHD. A single institution study of 12 patients receiving a second generation TKI after imatinib failure showed no negative impact on transplant engraftment, relapse rate of transplant-related toxicity when compared to historical controls. 10 A report by the Swedish CML registry 11 reviewed 118 patients transplanted between 2002 and 2017. 47.4% received an allo-HSCT in first CP. TKI resistance was the most common transplant indication (62.5%). For patients diagnosed with CML in CP at <65 years of age, the cumulative probability of undergoing allo-HSCT within 5 years was 9.7%. Overall 5-year survival was 96.2%, 70.1% and 36.9% when transplanted in first CP, second or later CP, and in accelerated phase or blast crisis, respectively. Non-relapse mortality for patients transplanted in CP was 11.6%.

# Timing of Transplantation
Multiple studies showed better outcomes in the pre-imatinib era if patients are transplanted in the first year after diagnosis. For example, in one study, patients transplanted within one year of diagnosis in chronic phase had a survival of 70% compared with 40% when transplanted beyond one year. 12 In the TKI era, early transplantation is no longer undertaken in patients meeting their milestones.

# Blood versus Marrow Stem Cell Source
Less relapse is seen in patients treated with peripheral blood stem cells (PCR positivity 44% with bone marrow versus 7% with peripheral blood at 4 years, p<0.009) but more chronic GVHD with peripheral blood. 12 Overall survival has been higher in peripheral blood transplants than bone marrow stem cell sources. In vivo T cell depletion with ATG decreases GVHD. The impact that ATG makes on altering relapse and GVHD outcomes between peripheral blood and bone marrow with the FLUBUP protocol is not fully understood.  

# Molecular Monitoring Post HCT for CML
A retrospective review of 346 patients followed with PCR every 3 months post-transplant found that while in the first 3 months post-transplant, PCR positivity did not correlate with worse outcome. At 6 months or later, it was highly correlated with relapse (42% PCR+ relapse versus 3% PCR-, p<0.0001; 4-year OS 74% versus 93%, p=0.002). 14 Between 6 and 12 months, the PCR+ patients had a relative risk of relapse of 26.0. However, at greater than 36 months, the short-term risk of relapse was much less; 15/59 were qualitative PCR+ but only 1 patient relapsed.
Quantitative PCR can be helpful in predicting relapse risk; at 3 to 5 months post-transplant, increasing PCR positivity is associated with increased risk of relapse. Relapse risk is 17% if PCR-, 43% if low level PCR+ (0.02%). 15 In a study of 379 patients alive at 18 months, 90 had at least 1 positive test at 18 months, but only 14% relapsed (median 40,000 copies/ug) compared to 1% of PCR-patients relapsing (69 had only 1 test positive with mean 24 copies/ug). 18 In a study of 98 patients, 69 had undetectable, decreasing, or low 50 copies/ug) titers (p<0.00001). 16 The correlation between blood and marrow PCR positivity is approximately 90%.
Based on this quantitative peripheral blood PCR for brc/abl transcript should be done every 3 months for 2 years then every 6 months to 5 years and then yearly to coincide with scheduled follow up appointments.

# Treatment of Relapsed Disease

# Treatment of Relapsed Disease Post-AlloHCT:
Imatinib is one therapy with moderate effectiveness in advanced relapsed disease post allogeneic HCT; in a review of 28 (5 chronic phase, 15 accelerated phase, 8 blast phase, 13  imatinib-naive patients who relapsed post-allotransplant, overall response to imatinib was 22/28, CCR 9/28 (35%), complete molecular response (CMR) 4/28. 17 All chronic phase patients attained CHR compared to 83% of the accelerated phase patients and 43% of the blast phase patients; one year overall survival was 74%. Five patients reactivated GVHD; three had grade III disease.
The second and third generation TKI's have not been systemically studied post transplantation but are presumed to be equally if not more efficacious than imatinib. One study published in abstract form only supports this. 19 DLI is also effective and can induce a complete molecular response in about 70% of patients. These can be durable, with a probability of 80-90% DFS at three years and improvement of OS from 53% without DLI to 95% with DLI at three years (p=0.0001). 7,15 There is an approximately 40% chance of GVHD greater than or equal to grade 2 and 30% chance of myelosuppression post-DLI. Responses are not generally durable in second chronic phase disease. The role of imatinib plus DLI is being investigated and a small number of patients have been reported with encouraging results. 20 A recent CIBMTR study retrospectively reviewed the outcomes of TKI vs. DLI vs. DLI + TKI in the setting of post-transplant relapse in the TKI era 21 . They found that patients who received a DLI alone had inferior survival compared with those who received a TKI with a DLI. Those who received a TKI alone had similar survival compared with those who received a TKI with a DLI supporting the use of a TKI alone following relapse. Therefore, initiation of TKI therapy with a second generation TKI, preferably one not used pre-transplant should be initiated if a positive PCR is detected 6 months posttransplant or if the BCR/ABL ratio is rising prior to that. If there is no response to TKI alone a mutation analysis should be sent. If there is no mutation proceed to escalating doses of TKI as per the relapse guideline section.
There is very little current data for more advanced phase relapses post-transplant. A mutation analysis should be sent. The next step is the minimization of immunosuppression as well as TKI therapy with-or without DLI should be considered in the accelerated phase potentially as a bridge to second transplant if the patient remains eligible. In the blast phase induction type chemotherapy in conjunction with TKI therapy should be undertaken prior to a second transplant if eligible. In this situation, the overall prognosis is poor and palliation is a reasonable choice. with refractory, transfusion-dependent anemia, peripheral blood blasts >2%, or adverse cytogenetics, and should have a donor search performed. 1 - All patients being considered for allotransplant should have mutation analysis by NGS and cytogenetics performed, if possible, to inform decision-making. - Patients in blast phase (>20% bone marrow blasts) should be given induction chemotherapy prior to proceeding with stem cell transplantation. - There is no convincing data to support the requirement for splenectomy or splenic radiation before transplantation. We do not recommend routine splenectomy or splenic irradiation pre-transplant. - Our standard conditioning is myeloablative busulfan + fludarabine + 4Gy TBI (see Conditioning chapter). - The use of JAK inhibitors pre-transplant is associated with improvement in constitutional symptoms and performance status, and decrease in spleen size, and can help improve clinical status prior to transplant. JAK inhibitors should be discontinued at the start of the conditioning for HSCT.

# Background
Myeloproliferative neoplasms (MPNs) originate from acquired mutations that target the hematopoietic stem cell and induce dysregulation of kinase signaling, clonal myeloproliferation, and abnormal cytokine expression. The JAK2 V617F mutation is most frequent. Other mutations include CALR, MPL, and other mutations including some with adverse prognostic implications such as ASXL1 (38%), EZH2 (7%), IDH1/2 (45), SFSF2 (14%) and U2AF1Q157 (8%) mutations 2,3,4 . Patients with triple negative disease status for JAK2, CALR and MPL are recognized to have adverse prognosis.
The 2016 WHO MPN classification is used to diagnose MPNs into categories including polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF), chronic neutrophilic leukemia, atypical CML, myeloid/lymphoid neoplasms associated with eosinophilia and rearrangements of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2, and overlap syndromes including chronic myelomonocytic leukemia and myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis. 5 abnormalities, autosomal trisomies (except +9), monosomal and complex non-monosomal karyotypes. High risk GPSS was also associated with higher blast transformation rate (HR 7.4, 95% CI 2. 1-26.3). In patients who had ambiguous prognosis based on differing scores by GPSS and by DIPSS-plus, those found to be higher risk on the GPSS were associated with poorer survival outcomes. 12 Secondary Myelofibrosis: None of the above prognostic tools were developed in patients who have secondary myelofibrosis after progression from polycythemia vera or essential thrombocytosis. In practice, the tools above are used but in a non-validated setting. There has been a model for prognosis developed in patients post-PV and post-ET: Myelofibrosis Secondary to PV and ET-Prognostic Model (MYSEC-PM), based on multivariate analysis of 685 patients with a median survival of 9.3 years. Secondary MF patients were divided into four risk categories based on: hemoglobin, circulating blasts, CALR status, platelet count and constitutional symptoms. Median survival according to risk group was: low (survival not reached), intermediate-1 (9.3 years), intermediate-2 (4.4 years), and high risk (2 years). 13 A calculator is available for the MYSEC-PM: / 

# Transplantation outcomes in myelofibrosis:
Allogeneic HCT is currently the only treatment option in myelofibrosis that is capable of inducing complete hematologic, cytogenetic, and molecular remissions. However, there are associated risks of treatment-related mortality, graft failure, and disease relapse.
A multicentre analysis of 100 consecutive transplants for myelofibrosis in patients treated with JAK inhibitors found that 2-year overall survival (OS) was 61%, but 91% for those who experienced clinical improvement pretransplant on JAK inhibitors, and 32% for those with leukemic transformation on JAK inhibitor therapy. 14 Age of the patients was 32-72 years (median 59). Response to JAK transformation increases with disease duration, affecting 3-10% in the first decade after diagnosis and 6-20% in the second decade. Progression to acute leukemia occurs in a small minority of patients, with incidences of 1-2.5% in the first decade after diagnosis, and 5-8% in the second decade, and continuing to increase thereafter. Similar patterns are seen with PV, with leukemic transformation reported as high as 20%. The use of cytoreductive therapy, including alkylating agents, is known to increase the rate of leukemic transformation, and thus the true rate of transformation is unknown. Very little literature exists of transplantation for these diseases, usually in the form of case reports. Prognosis with DIPSS-plus score is not validated in this population although it is commonly used. The problems and complications associated with myelofibrotic transformation of either ET or PV are similar to de novo PMF, thus therapy of post-ET MF or post-PV MF should be approached in the same manner.

# Use of JAK2 Inhibitors Prior to HSCT for Myelofibrosis
The JAK2V617F activating kinase mutation is seen in the many patients with BCR-ABL1 negative myeloproliferative patients, and Ruxolitinib, an oral JAK1/JAK2 inhibitor, is approved for the treatment of patients with symptomatic myelofibrosis, based on the data from two randomized phase 3 studies. Treatment is effective in patients without this specific mutation as other mutations in this pathway also cause symptoms. COMFORT-I and COMFORT-II compared ruxolitinib with placebo and bestavailable therapy (BAT), respectively, and found significant reductions in splenomegaly and improvement in constitutional symptoms. 20,21 Increased caloric intake and enhanced performance status as a result of improved constitutional symptoms and reduced splenomegaly could contribute to improved survival estimates for patients treated with ruxolitinib (71% vs. 54%, HR 0.48). 22,23 Longer follow-up will be needed.
It has been postulated that the anti-JAK2 mediated reduction in both cytokines and splenomegaly, as well as improvement in performance status, might improve outcome after allogeneic HSCT in patients with myelofibrosis. Some patients improve performance status and become transplant eligible. The down-regulation of inflammatory cytokines might have a beneficial impact on graft failure and has been seen to provide benefit in acute GVHD. The largest retrospective study examining transplant outcomes post ruxolitinib is outlined above and shows that pretransplant ruxolitinib therapy is feasible and patients responding to ruxolitinib have overall better transplant outcomes. 14 There were concerns that abrupt discontinuation of ruxolitinib in advance of transplant may result in cytokine storm reaction and severe inflammatory response. Preliminary reports from the JAK ALLO trial 24 of ruxolitinib prior to HSCT included ten patients who discontinued ruxolitinib, 7 of whom developed life-threatening events (including cardiogenic shock, tumor lysis syndrome, severe GVHD), with two deaths within 3 weeks of drug withdrawal. This pattern has not been seen in subsequent studies; the retrospective series of 100 patients above showed two with significant adverse events after they stopped drug more than 6 days pretransplant. 14 For this reason it is recommended to continue JAK1/2 inhibitors until the day before conditioning. 18 The average time to treatment failure with JAK 1/2 inhibitors in myelofibrosis is between two and three years. Ideally, patients should be referred for consideration of HSCT before they lose their response to these agents in order for them to undergo transplantation during a time of relatively good health. Several factors have been associated with a short (less than one year) time to treatment failure. These factors include "triple negative" myelofibrosis (negative for JAK2, MPL and CALR mutations) and ASXL-1 and EZH2 mutations, a high DIPSS-Plus score and those requiring transfusions at the time JAK 1/2 inhibitors are started. Patients with any of these risk factors should be referred at the time JAK1/2 inhibitors are started so that they can proceed to HSCT within one year or sooner. Patients with mutated CALR, 0-2 subclonal mutations without ASXL-1 or EZH2 mutations and those with mismatched donors should be followed closely and transplanted at the first sign of progression. 25 Fedratinib, another JAK2 inhibitor selective for JAK2 relative to other kinases has now been approved by Health Canada and funding recommendations made by CADTH for treatment of splenomegaly and/or disease-related symptoms in adult patients with intermediate-2 or high-risk primary myelofibrosis, post-polycythemia vera myelofibrosis, or post-essential thrombocythemia myelofibrosis, including patients who have been previously exposed to ruxolitinib. It is recommended for patients who are intolerant of ruxolitinib and not for patients with progressive symptoms after ruxolitinib therapy. Approval was made on the basis of the JAKARTA phase 3 randomized MF study for intermediate 2 and high risk disease with placebo and JAKARTA-2 in patients previously treated with ruxolitinib and who were refractory or intolerant. Reduction in spleen volume by 35% was seen in 30-40% of patients and there was improvement in Total Symptoms Score by 50% in one third of patients. Thiamine levels are required and supplementation is necessary, and monitoring for symptoms of encephalopathy is required. Other side effects include cytopenias and GI intolerance that should be proactively managed. Current data supports fedratinib's use post ruxolitinib failure if funding is available. For patients planned for allogeneic stem cell transplant, transplant should occur earlier in the course of disease prior to multidrug resistance and before second line therapy is required for refractory disease. If fedratinib is used frontline prior to stem cell transplant, there is no evidence around management of medication prior to BMT and we would discontinue medication as per ruxolitinib protocol.
www.ahs.ca/guru BMT Standard Practice Manual 

# Summary
- Factors favoring allogeneic stem transplantation over conventional therapy include higher disease risk (high risk cytogenetics, MRD positive, short duration of response, Richter transformation) and low transplant risk (younger age, lack of co-morbidities, well-matched donor) - Allogeneic stem cell transplantation may be offered to CLL patients with:
- Relapse after at least 1 prior novel agent (BTKi and/or BCL2 inhibitor), preferably responding to a second agent as salvage treatment o Richter transformation responding to treatment, particularly if high-risk features such as previously treated CLL, TP53 mutated or clonally related Richter transformation, relapsed disease, or failure to achieve complete response to R-CHOP - Autologous stem cell transplantation is not indicated to treat CLL but may be considered in selected patients with chemosensitive Richter transformation Background Chronic lymphocytic leukemia (CLL) represents one of the most common lymphoid malignancies of adults. With a median age at diagnosis of 70 years, many patients with this disease will die of other causes. For young patients however, this diagnosis represents a serious threat to life and aggressive management with high-dose therapy and blood stem cell transplantation (SCT) is a reasonable treatment option. This is particularly the case for patients whose CLL is associated with deletion chromosome 17p13.1 , which is observed in 5% of untreated CLL cases but in up to 30% of relapsed and refractory cases. CLL with del(17p) usually require therapy within 1 year of diagnosis and is now being treated with frontline BTK inhibitors such as ibrutinib. Even novel agents such as ibrutinib do not control del(17p)-associated CLL for long durations of time. A recent study by O'Brien and colleagues involving 144 patients with relapsed del(17p) CLL reported 2-year progression-free survival (PFS) rates of approximately 60% (mPFS of 30mo) and 24-month OS of 75% 1 .
For a review of the diagnosis, staging, prognosis, assessments of patient fitness and response, and current treatment recommendations of the Alberta Provincial Hematology Tumour Team, please refer to the CLL Clinical Practice Guideline (LYHE-007).

# Stem Cell Transplantation in CLL
Data from the Center for International Blood and Marrow Transplant Research (CIBMTR) suggests that CLL is an infrequent indication for transplant. The majority of transplants reported were allogeneic, many of which were carried out after reduced intensity or non-myeloablative conditioning.

# Allogeneic Stem Cell Transplantation in CLL
Long-term survival after allogeneic SCT for CLL of the largest series of patients (n=2589), who underwent transplant between 2000 and 2010, has been reported from the European Group for Blood and Marrow Transplantation (EBMT) 2 . In this series, long-term disease control was established for patients, but with longer follow-up both event-free and overall survival decreased over time (62% at 2 years vs. 35% at 10 years for OS; 49% at 2 years vs. 28% at 10 years for EFS). The incidence of relapse was 21% at 2 years vs. 32% at 10 years, and non-relapse mortality 30% at 2 years vs. 40% at 10 years. The presence or absence of del(17p)/TP53 mutation has not been shown to impact outcome of alloSCT 3,4 . Risk factors for relapse included active disease at time of transplant, T-cell depletion with alemtuzumab, prior autologous SCT, and use of mismatched donor, while absence of MRD at 12 months was highly prognostic for reduced relapse risk 2,3,4 .
In regards to donor selection, the EBMT analyzed 368 chronic lymphocytic leukemia patients who underwent allogeneic hematopoietic stem cell transplantation between 1995 and 2007 5 . There were 198 HLA-identical siblings; among unrelated transplants, 31 were well matched in high resolution ('well matched' unrelated donor, WMUD), and 139 were mismatched (MM), including 30 matched in low resolution; 266 patients (72%) received reduced-intensity conditioning and 102 (28%) received standard. There was no difference in OS at 5 years between HLA-identical siblings (55% (48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)) and WMUD (59% (41-84)), p=0.82. In contrast, OS was significantly worse for MM (37% (29-48) p=0.005) due to a significant excess of transplant-related mortality. HLA matching had no significant impact on relapse (siblings: 24% (21-27); WMUD: 35% (26-44), p=0.11 and MM: 21% (18-24), p=0.81); alemtuzumab T-cell depletion and stem cell source (peripheral blood) were associated with an increased risk. As the toxicity of haploidentical transplants have been greatly decreased with the use of post-transplant cyclophosphamide, donor availability for transplantation has increased. The EBMT has reported the outcome of 117 CLL patients who had received an allogeneic SCT with a haploidentical donor, with results appearing almost identical to those with HLA-matched donors; 5-yr OS 38%, PFS 31%, CI of relapse 26%, and NRM 44% 6 .
Myeloablative conditioning (MAC) is associated with improved overall survival in acute myeloid leukemia (AML), where the increased risks of NRM and acute and chronic GVHD associated with MAC were offset by the significant reduction in relapse 7 . It is unclear if these results can be extrapolated to patients with CLL, given that CLL is an indolent disease with high susceptibility to GVL which may not necessarily require intensive chemotherapy; patients with CLL may be at higher risk of NRM due to older age and underlying immune dysregulation; allotransplant recipients with CLL are heavily pre-treated which may confer greater resistance to MAC; and there may be more options to treat relapse after allotransplant in CLL, such as donor lymphocyte infusion and emerging therapies (e.g. non-covalent BTK inhibitors, CAR-T cells). Retrospective and transplant registry studies conclude that reduced intensity conditioning (RIC) is associated with lower risks of NRM, less acute and chronic GVHD, and similar or improved OS compared to MAC in CLL 8,9,10,11,12,13 . Indeed, intensive conditioning is not necessarily indicated since CLL has among the lowest relapse risk after non-myeloablative (NMA) conditioning of any hematologic malignancy 14 . An EBMT registry study also concluded that selected patients receiving NMA conditioning have similar relapse incidence, relapsefree survival (RFS), and overall survival as recipients of RIC in CLL 15 . As a result, the majority of allotransplants (75-80%) performed for CLL in North America and Europe employ RIC or NMA conditioning, and ASTCT guidelines recommend RIC or NMA conditioning for all patients undergoing allotransplant for CLL 2,16,17 . MAC with FluBu4 was utilized for most allotransplant recipients with CLL in Alberta until 2022, at which time a review of local outcomes revealed high rates of acute and chronic GVHD and low mod/severe chronic GVHD and RFS (cGRFS) despite the use of ATG (Table 3). As a result, in February 2023 RIC was adopted as the preferring conditioning regimen for patients with CLL to reduce their risks of acute and chronic GVHD as well as other acute toxicities and NRM.  The EBMT studied 44 patients with 17p-CLL who received allogeneic hematopoietic SCT between March 1995 and July 2006 from a matched sibling (n = 24) or an alternative donor (n = 20) 20 . Patients had received a median of 3 lines of chemotherapy before SCT, and at the time of transplantation, 53% of patients were in remission. RIC was applied in 89% of patients. Acute or extensive GVHD occurred in 43% and 53% of patients, respectively. Nineteen patients were alive at the last follow-up (median observation time 39 months), and no late relapse occurred in 9 patients with a follow-up longer than 4 years. The 3-year OS and PFS rates were 44% and 37%, respectively.
It is clear that with the approval of novel agents including BTK inhibitors (e.g. ibrutinib, acalabrutinib), PI3 kinase inhibitors (e.g. idelalisib), and the BCL2 inhibitor venetoclax, the number of transplants being performed for CLL continues to decline, particularly for those patients without high risk cytogenetics. In a study of 65 patients with prior novel agent exposure who underwent alloSCT, the 24 month PFS, OS, NRM, and relapse incidence was 63%, 81%, 13%, and 27%, respectively 12 . Poor-risk disease characteristics, prior NA exposure, complete vs. partial remission status, and transplant characteristics were not independently associated with PFS; 1 vs.  novel agents, or ibrutinib vs. venetoclax as the line of therapy immediately pre-alloHSCT had no impact on PFS or OS; only HCT-CI independently predicted for PFS. It remains to be seen whether combinations of these agents will alter the natural history of the disease, or whether they are just delaying the use of allogeneic SCT until later in the disease course. Allogeneic SCT will continue to have a role for patients who fail or are intolerant to these therapies.
Overall, allogeneic stem cell transplantation (HSCT) should be considered for fit patients who are younger than 65 years of age and have CLL that did not respond or have progressed after treatment with at least one novel agent (either BTKi and/or venetoclax). This is especially important in patients with higher disease risk, including complex karyotype, high risk cytogenetics (del17p/TP53), short duration of response, and MRD positive (on venetoclax).

# Richter Transformation:
Richter transformation (RT) of CLL into an aggressive DLBCL occurs in 1-5% of patients with CLL. RT is associated with a dismal prognosis with PFS <25% with CHOP-based chemoimmunotherapy and median survival 6-12 months 21,22,23,24 . Given these poor outcomes, consolidation with allogeneic HCT should be considered for eligible patients with responding disease who have relapsed RT or other high-risk features, such as previous therapy for CLL, failure to achieve a complete response to R-CHOP, TP53 aberrations, or clonally related RT 24,25,26,27 . Although <10% of all patients with RT will ever undergo allogeneic HCT, this may represent a curative therapy for selected cases with 3year PFS 43%, OS 52%, relapse incidence 30%, and NRM 27% in a CIBMTR study of 118 allogeneic HCT recipients 28 . Outcomes were best for patients in complete response (3-year PFS 66%) or partial response (3-year PFS 43%) at the time of HCT compared to those with resistant disease (3-year PFS 5%). The majority of patients with RT receive reduced intensity conditioning, which has been www.ahs.ca/guru BMT Standard Practice Manual Last Reviewed: February 1, 2023 Effective: February 3, 2023 associated with similar to improved outcomes in this setting compared to myeloablative conditioning 28,29,30,31 .
Importantly, patients with RT arising from treatment naive CLL appear to have comparatively better outcomes with R-CHOP and may not necessarily require allogeneic HCT 23,24 . In an Alberta study of 99 patients with RT, those with treatment naive CLL had higher response rates to first line chemoimmunotherapy (71% versus 40%) and superior 2-year OS (51% versus 28%) compared to those with previously treated CLL. Nevertheless, 2-year OS remained suboptimal at 53% for the 13 patients 70 years old with RT and treatment naive CLL, which suggests there may be a role to consider consolidation with autologous HCT for these patients, similarly as other high risk aggressive lymphomas. Although data is lacking on the outcomes of autologous HCT as part of first-line therapy for RT, a CIBMTR study of 53 patients undergoing autologous HCT for predominantly relapsed RT reported 3-year PFS 48%, OS 52%, and relapse incidence 37% 28 . In an EBMT study of 34 patients who underwent autologous HCT, only 11 of 17 relapses were related to RT (the remainder were due to CLL), suggesting autologous HCT may eradicate the RT component in many patients even though the underlying CLL may persist 29 . It should be noted that even if allogeneic HCT may not be required as a part of primary therapy for patients with lower-risk RT, a referral for transplant consultation and HLA typing is suggested at diagnosis in all patients who are eligible for allogenic HCT by age and/or comorbidities, given the significant risk of relapse/refractory disease with RT.
Less commonly, patients with CLL may develop a Hodgkin lymphoma variant of RT which is often clonally unrelated to the CLL. Available evidence suggests that Hodgkin-variant RT has similar outcomes with standard chemotherapy as de novo Hodgkin lymphoma in this age group 32,33 . As such, there is not an established role for consolidation with HCT in these cases 27 .

# Autologous Stem Cell Transplantation in CLL
Case series from a number of institutions report high overall survival (4-year OS 65-94%) with low TRM (4-10%) of autologous stem cell transplantation (ASCT) for CLL; however, to date, no randomized study has demonstrated an OS advantage for the use of ASCT in CLL. Despite a strong PFS advantage in the published studies of ASCT, ASCT is now rarely used for CLL  . This is because FCR (fludarabine, cyclophosphamide, and rituximab) is now used as front-line therapy for most young CLL patients, as it has been shown in a randomized, controlled trial, to provide an OS advantage. Published studies of ASCT in CLL predate the introduction of FCR chemotherapy so the role that ASCT could play in the era of FCR is unclear. Additionally, the use of 6 cycles of a fludarabine-containing regimen significantly impairs the subsequent ability to mobilize and collect autologous blood stem cells. With the emergence of novel agents for relapsed CLL, the role of ASCT is even more unclear. At present, there are no definite indications for ASCT for CLL.   An excisional lymph node biopsy of the largest regionally involved lymph node is the optimal specimen for initial diagnostic assessment. Similarly, a sizable biopsy from the organ of origin in extranodal lymphomas is also suitable. Occasionally, needle core biopsies may be adequate but this needs to be assessed on a case-by-case basis. Whenever possible, a reference lymphoma pathologist should confirm the diagnosis. The following histological sub classification of the malignant lymphomas is an adaptation of the World Health Organization (WHO) classification and is based on the light microscopic interpretation complemented by special stains, immunophenotyping, cytogenetics and other information as available. The specific lymphomas are divided into three major groups for treatment planning. All B-Cell lymphomas should be immunophenotyped to determine if they are positive for CD20. Abbreviations: aaIPI = age-adjusted international prognostic index; Alk P = alkaline phosphatase; ALT = alanine aminotransferase; ASCT = autologous stem cell transplant; BL = Burkitt lymphoma; CBC = complete blood count; CSF = cerebrospinal fluid; CT = computerized tomography; DLBCL = diffuse large B cell lymphoma; ECOG = Eastern Cooperative Oncology Group; HDCT = high-dose chemotherapy; LBL = lymphoblastic lymphoma; LDH = lactate dehydrogenase; LP = lumbar puncture; PA = posterior-anterior; PET = positron-emission tomography. Absence of any one of these factors does not constitute an absolute contraindication to HDCT/ASCT, and successful outcomes have been reported in a variety of poor prognosis settings, even HIV infection. 2,3 It is widely accepted, however, as the number of unmet eligibility criteria increases, the likelihood of a poor outcome from SCT also increases. feasible, but most disease-related outcomes are statistically inferior to younger patients. 4,5 For example, in multivariate analysis, while adjusting for patient-, disease-, and treatment-related variables, older patients with aggressive histologies were 1.86 times (95% CI 1.43-2.43, P < .001) more likely than younger patients to experience treatment-related mortality (TRM). 5 

# Staging System

# Autologous Stem Cell Transplantation Eligibility Criteria
A. Diffuse Large B-cell Lymphoma (DLBCL)

# Indications and Outcomes:
Diffuse Large B-cell Lymphoma (DLBCL) accounts for approximately 1/3 of all lymphomas, and represents the majority of patients treated in SCT studies for aggressive lymphoma. 6 HDCT/ASCT has been standard therapy for chemosensitve relapsed/refractory DLBCL ever since the results of the PARMA study were published more than a decade ago. 7 The PARMA study is the only randomized controlled trial (RCT) of high dose versus conventional dose salvage chemotherapy for relapsed, chemosensitive NHL, and demonstrated a significant failure-free (51% vs. 12%) and overall survival (OS) (53% vs. 32%) advantage for high dose BEAC (BCNU, etoposide, Ara-C, cyclophosphamide) and ASCT over standard-dose DHAP (dexamethasone, Ara-C, cisplatin). This was found despite the fact that not all patients allocated to the HDCT arm of the trial actually received HDCT, and many patients in the control arm eventually underwent HDCT/ASCT at the time of second disease progression.
The major prognostic factors for outcome of relapsed DLBCL include the time to relapse, IPI (international prognostic index) risk factors, and chemosensitivity. In the PARMA study, time to relapse <1 year was associated with a 40% response to DHAP, and only 13% 8 year OS. 8 Costa and colleagues reported mean OS of only 5 months for patients with both a time to relapse <18 months as well as IPI=3-5, suggesting that these poor prognosis patients should not be subjected to ASCT. 9 Hamlin and colleagues reported that the salvage aaIPI predicts outcome of relapsed DLBCL with PFS rates of approximately 69%, 46%, 25% for chemosensitive relapsed DLBCL patients with aaIPI scores of 0, 1, and 2-3, respectively. 10 More recently, in the first interim analysis of 200 patients treated in the CORAL study (R-ICE Versus R-DHAP in relapsed DLBCL patients, followed by ASCT +/-maintenance rituximab) reported by Gisselbrecht and colleagues, factors associated with response to salvage therapy were refractory or relapse <12 months (52% vs. 88%), sIPI (second-line International Prognostic Index) 2-3 (54% vs. 77%), and relapse after prior rituximab (54% vs. 82%). 11 (  13 For NHL, the 2-year FFS was 67%, 56%, 26%, and 12% for aaIPI 0, 1, 2, 3, respectively. The 2-year failure-free survival (FFS) by PET response to salvage DHAP-VIM was 72% for complete response (CR), 38% for partial response (PR) and 10% for no response (NR). The two factors were combined by assigning 0 points for CR, 1 point for PR, and 2 points for NR on PET imaging. The 2year FFS rates were 82%, 58%, 24% and 5% for patients with a combined risk score of 0-1, 2, 3, and 4-5 points, respectively. 13 Using evidence from the above studies, it is therefore probable that relapsed DLBCL patients can be appropriately excluded from ASCT if they have three, and possibly even two of the following adverse prognostic factors:
- time to relapse of <12months
- relapse aaIPI scores of 2-3
- chemoresistance as defined as lack of at least a PR to salvage chemotherapy
No RCT has been conducted to evaluate potential benefit of HDCT/ASCT for patients with chemoresistant relapsed/refractory large cell lymphoma (i.e. patients who do not respond to secondline chemotherapy) or for patients who have experienced failure of more than one prior chemotherapy regimen. Retrospective reports, however, suggest only low rates of long-term progression-free survival (PFS) following HDCT for these poor prognosis patients. As such, in many transplant centres, ASCT is not offered in these settings.
Conflicting results have been reported from RCTs evaluating first remission-consolidation with HDCT/ASCT for aggressive NHL. 14 Many studies were negative, while a few have shown significant PFS benefits from HDCT. Criticisms of these studies, however, are numerous. Many studies had inadequate statistical power, most did not use the aaIPI as an eligibility or stratification criterion, and overall they were extremely heterogeneous with respect to histological subtypes, choice of standard and HDCT regimens, and timing of HDCT relative to number of induction chemotherapy cycles. Some studies used a non-conventional, intensive chemotherapy "control arm". These studies reported that up to 40% of patients in the HDCT arm never received the assigned HDCT, often due to an inadequate response to abbreviated induction chemotherapy prior to planned HDCT/ASCT. The use of abbreviated induction therapy followed by a single HDCT/ASCT is not considered a viable strategy for future trials. Greb and colleagues performed a systematic meta-analysis searching the Cochrane Library, MEDLINE and other databases (1990 to 2005) for studies that evaluated the efficacy of frontline HDCT relative to conventional chemotherapy in aggressive NHL. 15 32). There was, however, improved OS in the subgroup of aaIPI=3 patients (82% vs. 64%). 17 Other approaches still worthy of study involve multiple cycles of high dose sequential induction chemotherapy as pioneered by groups in Italy, 18 or early identification of patients who are unlikely to be cured by standard induction therapy through the use of interim response PET/CT imaging after 2-4 cycles of chemotherapy, and then treating unfavorable responders with immediate salvage HDCT/ASCT. 19 HDCT/ASCT as Part of Initial Therapy for DLBCL: Secondary CNS Lymphoma:  Selected patients with CNS relapse/progression may be candidates for aggressive therapy. One of 3 induction regimens is recommended for transplant-eligible patients and one of two options for transplant in-eligible patients, based on presentation:
Randomized
1) Isolated CNS lymphoma: HDMTX-based induction then RDHAP for stem cell mobilization and collection, then R-TBuM/ASCT for transplant eligible or HDMTX/AraC then ifosfamide for transplant ineligible.
2) Early Systemic and CNS lymphoma (prior to completing RCHOP x6): RCHOP and HDMTX x4 cycles then RDHAP for stem cell mobilization and collection, then R-TBuM/ASCT for transplant eligible or RCHOP/MTX followed by AraC then ifosfamide in transplant ineligible.
3) Late relapse (prior RCHOP x6) with systemic and CNS lymphoma: HDMTX-ifosfamideetoposide x2 then RDHAP for stem cell mobilization and collection, then R-TBuM/ASCT for transplant eligible or palliation for transplant ineligible.
Unfortunately, most patients with secondary CNS lymphoma experience poor response to salvage therapy, including high dose methotrexate/cytarabine-based regimens. These patients who are unfit to receive or do not respond to high dose methotrexate/cytarabine-based therapy are best managed with palliative intent, including possible use of intrathecal chemotherapy or palliative cranial radiotherapy.
BMT Standard Practice Manual 

# Double hit lymphoma with MYC and BCL2 mutations/rearrangements by FISH.
The largest multicentre retrospective analysis of 311 double hit lymphoma patients reported an OS rate of 80% if IPI=0. 27 In addition, the OS rate was approximately 90% for 39 patients who achieve CR following induction chemotherapy and then underwent SCT compared to 60% for 112 patients who achieved CR but did not receive SCT. Although this numerical difference was not statistically significant (p=0.1), it was very clinically significant, indicating that the study was underpowered to draw any meaningful conclusions regarding the role of ASCT consolidation.
More recently, reported outcomes of 159 patients with double-hit lymphoma who achieve CR following induction therapy. 28 This study demonstrated that PFS and OS were superior with an intensive regimen relative to RCHOP, and that ASCT only improve outcomes for patients who initially received RCHOP, but not an intensive regimen. These studies suggest that DHL patients treated with RCHOP should be considered for ASCT consolidation, especially those with IPI=2-5 at diagnosis, however other patients who achieve CR after an intensive induction regimen (such as DA-EPOCH-R or R-CODOXM/IVAC) probably should not receive ASCT consolidation. Due to the lack of prospective randomized controlled studies, however, it is impossible to determine if the optimal approach involves RCHOP induction followed by ASCT or an intensive induction chemotherapy regimen.
Alberta recommendations for special DLBCL entities. 

# B. Primary CNS Lymphoma
Conventional therapy for primary central nervous system lymphoma (PCNSL) involves high dose methotrexate-based induction, potentially followed by cranial radiation, although long term outcomes are poor, especially for patients over age 50 years or with poor performance status at diagnosis. 29,30 In addition, high dose methotrexate followed by cranial radiation is associated with a high risk of dementia and neurotoxic death in patients over age 50-60 years. 31 If patients refuse radiotherapy because of the concern regarding radiation-induced dementia, and fulfill standard eligibility for ASCT, they should be considered for high dose thiotepa, busulfan-based chemotherapy and autologous stem cell transplantation as part of their initial treatment, or at the time of first relapse following initial therapy since reports suggest long term progression free survival rates of 40-50% with this approach. 32,33 Choice of Re-induction Therapy Prior to HDCT/SCT: Several salvage chemotherapy regimens exist for relapsed DLBCL, but RCTs have not been performed to determine whether one regimen is superior to another. 34 Most regimens involve prolonged intravenous administration and therefore, require hospitalization. The GDP regimen (gemcitabine 1g/m 2 IV days 1 and 8, dexamethasone 40mg p.o. days 1-4, cisplatin 75mg/m 2 IV day 1) can easily be administered on an outpatient basis, and has been reported by the NCIC CTG to give 49% response rate in 51 patients with the relapsed/refractory NHL. 35 This is similar to other salvage chemotherapy options such as ICE or DHAP. The NCIC CTG LY12 trial is currently evaluating RDHAP versus RGDP for relapsed/refractory aggressive NHL, with responding patients proceeding to HDCT/ASCT and then to a second randomization between observation and rituximab consolidation therapy every 2 months for one year. The other RCT examining salvage regimens for relapsed DLBCL, the CORAL study, thus far shows similar response rates and PFS rates for the RICE and RDHAP treatment arms. 11 There is some suggestion from phase II studies that intensive salvage therapy prior to HDCT/ASCT may improve OS rates, but this needs to be proven in well conducted RCT before wide adoption. 36,37 Finally, rituximab combined with salvage chemotherapy has been shown in a RCT and several historically controlled studies to improve post-ASCT outcomes relative to salvage chemotherapy alone.  The majority of this data involves patients who did not receive rituximab with their primary CHOP-like initial induction therapy prior to relapse. Nevertheless, rituximab is now commonly added to salvage therapy regimens, at least for patients who relapsed more than 6-12 months after completing initial RCHOP, or who never received rituximab with primary chemotherapy.
In 

# High Dose Therapy Regimen:
The most common HDCT regimens used for lymphoma include: cyclophosphamide, etoposide, carmustine (CEB or CBV), carmustine, etoposide, cytarabine, melphalan (BEAM), fractionated totalbody irradiation (fTBI) with cyclophosphamide (Cy) and possibly etoposide (VP-16) (CyTBI or VPCyTBI) and, melphalan, etoposide with or without TBI (MeVPTBI). RCTs comparing these regimens for lymphoma have not been conducted. Non-randomized retrospective studies suggest somewhat better efficacy and tolerability for BEAM over CBV or the TBI-containing regimens in the setting of aggressive lymphoma.  For example, Salar and colleagues investigated the impact of the preparative regimens on the outcome of 395 patients with diffuse large cell lymphoma, consecutively reported to the registry of the Spanish GEL/TAMO. 45 Conditioning consisted of chemotherapy-only in 348 patients (BEAM, n=164; BEAC, n=145; and CBV, n=39) and CyTBI in 47 patients. Median times to engraftment and discharge were significantly shorter in the chemotherapyonly group, and early TRM was significantly higher with CyTBI. Survival rates of patients conditioned with BEAM or BEAC (58%, 95% CI 50-66) was more favourable than with CBV (40%, 95% CI 24-56), and significantly better than with CY-TBI (31%, 95% CI 18-44), a finding that persisted in multivariate analysis. Other studies suggest that high TBI doses (>12Gy) or combinations of TBI and etoposide may increase the risk of secondary myelodysplasia/AML, and are to be discouraged. 46,47 Perhaps the use of targeted TBI though radioimmunoconjugates will improve the efficacy while reducing toxicity of TBI, however, this has yet to be proven in randomized studies. 48 Primary CNS Lymphoma requires chemotherapy agents that cross well through the blood brain barrier such as busulfan and thiotepa (eg. thiotepa 600mg/m 2 , busulfan 9.6 mg/kg) rather than agents that penetrate poorly such as melphalan and etoposide. 32 Post-ASCT Therapy: G-CSF 5g/kg/day is generally given to all ASCT patients starting day +7 post-SCT until ANC >1. hospital stay compared to no G-CSF, as well as trials showing no significant benefit of using higher doses of G-CSF or starting G-CSF earlier post-SCT.  

# C. Mantle Cell Lymphoma
Mantle-cell lymphoma (MCL) is characterized by poor prognosis with a median survival of only 3 to 5 years following conventional therapy, and little improvement in outcome when rituximab is added to conventional CHOP. 53,54 In 1996, the European MCL Network initiated a randomized trial comparing consolidation with CyTBI/ASCT (TBI 12 Gy, cyclophosphamide 120 mg/kg) to a conventional interferon maintenance (6x10 6 IE IFN- 3x weekly) for patients under 65 years of age who were in first remission after a CHOP-like induction regimen. 55 A total of 232 previously untreated patients with advanced stage MCL were randomized upfront. Only 173 (76%) of 228 evaluable patients responded to initial induction chemotherapy, and 151 of these (87%) proceeded to the assigned consolidation therapy. Baseline characteristics were comparable in the per-protocol and intent-to-treat cohorts. By intent-to-treat, and after a median follow-up of 6.1 years, patients in the ASCT study arm experienced a significantly longer median time to treatment failure of 2.6 versus 1.4 years (p=0.0001) as well as longer median OS of 7.5 versus 5.3 years (p = 0.031). 55 Accordingly, first-remission HDCT/ASCT represents the current therapeutic standard in younger MCL patients. The second Nordic MCL phase II trial in 160 patients suggests that HDCT/ASCT outcomes can possibly be improved upon by the addition of high dose Ara-C and rituximab, with projected 6-year overall, event-free, and progressionfree survival rates of 70, 56 and 66%, respectively, with no relapses occurring after 5 years. 56 Other single centre reports suggest R-HyperCVAD induction followed by HDCT/ASCT may also a reasonable strategy, but confirmatory RCTs are lacking. 57 Because virtually all MCL patients eventually relapse following autologous SCT, and relapse rates are known to be lower following allogeneic SCT, allogeneic SCT may be the preferred strategy for eligible patients in poor prognosis situations including first partial remission with several IPI risk factors or peripheral blood involvement at diagnosis, or patients in first relapse.  Robinson and colleagues recently reported a large retrospective EBMT study of reduced intensity SCT (RIST) in MCL. 61 Between 1998 and 2006 279 patients with MCL received RIST with 210 procedures performed after the year 2001. Patients had received a median of 3 lines (range 1-9) of prior therapy and 119 (43%) had undergone a previous autologous SCT. The median time from diagnosis to transplant was 30 months (range 3-161). Conditioning for RIST was achieved with fludarabine plus an alkylating agent in 66%, fludarabine plus TBI in 13%, and a variety of other reduced intensity regimens in 20%. The 100 day, 1 year and 3 year non-relapse mortality rates were 13, 32 and 41% respectively. The Kaplan-Meier estimate of the PFS at 1 and 3 years was 49% and 29% respectively. PFS was significantly worse for patients with refractory disease (response rate (RR)=2.2, p<0.001), poor PS (RR=2.6, p=0.005) or those transplanted prior to 2002 (RR=1.5, p=0.03).

# D. Peripheral T-Cell Lymphoma
In North America, peripheral T-cell lymphomas (PTCL) represent 5-10% of all lymphomas. 62  www.ahs.ca/guru 16 lymphoma (AITL) (16%). With the exception of CD30+ anaplastic large cell lymphoma (ALCL), PTCLs are associated with only 10-20% chance of long-term progression-free survival following conventional chemotherapy. Some small single-centre reports of HDCT/ASCT for relapsed/refractory PTCL suggest poor PFS rates of only 10-20%, 63,64 while other reports, including larger transplant registry series, suggest outcomes similar to those for relapsed DLBCL,  with uniformly superior outcomes for ALCLs compared to other PTCLs.
Nickelsen and colleagues reported a retrospective analysis on 424 patients with mature T-cell lymphoma who received HDCT/ASCT in EBMT centres between 2000 and 2005. 68 Histological subtypes were ALCL=98, PTCLu=176, AITL=120, unknown=30. Median time from diagnosis to ASCT was 9 months (range=4-99), and median follow up for surviving patients was 36 months (range=0. 17 patients who received their transplants in CR were 70% and 56%, compared to 42% and 30% for patients with chemotherapy-sensitive relapsed disease, and 23% at both time points for patients with chemotherapy-refractory disease. Available retrospective and phase II evidence, therefore, suggests that PTCL patients can benefit from HDCT/ASCT when used in the settings of chemosensitive relapse, or first remission consolidation. 74 RCTs evaluating treatments for these uncommon lymphomas are lacking, however.

# E. Lymphoblastic Lymphoma
Lymphoblastic lymphoma (LBL) is a rare, clinically aggressive neoplasm of the young that frequently involves the bone marrow and/or central nervous system. 75 These patients require aggressive combination chemotherapy (similar to acute lymphoblastic leukemia therapy) with induction, consolidation, prophylactic intrathecal chemotherapy and either maintenance therapy or first remission autologous stem cell transplantation. Sweetenham and colleagues reported a prospective RCT comparing a first remission HDCT/ASCT to conventional-dose consolidation and postremission maintenance chemotherapy in adults with lymphoblastic lymphoma. 76 77 Randomization was stratified based upon duration of remission, remission status, and prior cranial irradiation. A total of only 43 patients were enrolled. At a median follow-up of 43 months, event-free survival was 29% in the busulfan arm and 58% in the TBI arm (p=0.03). 77 Because LBL is similar to ALL, some centers prefer allogeneic hematopoietic SCT to autologous SCT. The IBMTR and ABMTR databases were retrospectively analyzed for outcomes of LBL patients who underwent autologous (auto, n=128) or HLA-identical sibling (allo, n=76) SCTs from 1989 to 1998. 78 Allogeneic SCT (alloSCT) recipients had higher TRM at 6 months (18% versus 3%, p=0.002), and this disadvantage persisted at 1 and 5 years. Significantly lower relapse rates were observed in alloSCT recipients at 1 and 5 years (32% versus 46%, p=0.05; and 34% versus 56%, p=0.004, respectively), but no differences were noted in 5 year lymphoma-free survival rates (36% versus 39%, p=0.82) or 5 year OS (44% versus 39%, p=0.47) between alloSCT and autoSCT. Multivariate analyses to account for confounding factors confirmed these results. In summary, alloSCT for LBL is associated with fewer relapses compared to autoSCT, but higher TRM offsets any potential survival benefit. Independent of SCT type, bone marrow involvement at the time of transplantation and disease status more advanced than first complete remission were associated with inferior outcomes. 

# F. Burkitt Lymphoma
True Burkitt lymphoma is rare, representing <1% of all lymphomas. 80 As such, treatments for this entity have not been evaluated in RCTs. Conventional primary induction therapy consists of intensive chemotherapy with CNS prophylaxis using regimens such as CODOX-M/IVAC. 81 SCT is generally reserved for recurrent disease or chemo-sensitive primary induction failures. There is very little data on SCT for Burkitt lymphoma, and no evidence that allogeneic SCT is superior to autologous SCT for this disease. Therefore, patients with relapsed/refractory Burkitt lymphoma who fulfill standard eligibility criteria for autologous SCT indicated above, are usually treated with this approach. The largest series of Burkitt lymphoma patients undergoing SCT was reported by the EBMT in 1996 by Sweetenham and colleagues. 82 This study of 117 patients included Burkitt and Burkitt-like lymphomas in first remission (n=70) or relapse/refractory states (n=47). The 3 year OS rate following SCT was 72% for patients in first remission, 37% in chemo-sensitive relapse, and 7% for chemo-resistant patients.
References: for commercial use by Health Canada. All three products target CD19, but the products differ in the co-stimulatory domains used, the viral vector used to engineer the products, and the lymphodepletion chemotherapy used prior to product infusion.
Information regarding the recommended lymphodepletion chemotherapy regimen for each product can be found in the product monographs. Information on the grading, prevention, and management of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity can be found in the dedicated chapter on these topics in the Alberta Bone Marrow and Blood Cell Transplant Program Standard Practice Manual.
The efficacy of tisa-cel in DLBCL was initially demonstrated in the JULIET trial. 1 This was a single-arm phase 2 trial in which 111 patients with relapsed or refractory DLBCL were treated with tisa-cel. The trial included patients with transformed follicular lymphoma as well as patients with double or triple hit lymphomas, but did not include patients with primary mediastinal B cell lymphoma. The most recent update showed a PFS of 31% and an OS of 36% at 36 months. 2 The median PFS and OS in patients who received tisa-cel were approximately 3 months and 12 months, respectively. 22% of patients had grade 3 or higher cytokine release syndrome, and 12% of patients had grade 3 or higher neurotoxicity. There were no reported deaths due to CRS or neurotoxicity.
The efficacy of axi-cel in DLBCL was initially demonstrated in the ZUMA-1 trial. 3 This was also a single-arm phase 2 trial, in which 101 patients with relapsed or refractory DLBCL were treated with axi-cel. The trial also included a small number of patients with primary mediastinal B-cell lymphoma. Unlike in JULIET, bridging therapy was not allowed. The OS at 48 months was 44%. PFS was not reported at the 48-month time point, but the median PFS in patients who received axi-cel was 5.9 months, and the median OS was 25.8 months.  13% of patients had grade 3 or higher CRS, with 1 associated death. 28% of patients had grade 3 or higher neurotoxicity. The EMBT and CIBMTR are both maintaining registries of patients treated with both tisa-cel and axicel. Real-world data has thus far demonstrated similar or better outcomes as compared to those seen in the pivotal trials.
The CIBMTR data for tisa-cel (n=152, median follow-up 11.9 months) demonstrated comparable ORR (62%), CR (40%), 6-month PFS (39%) and 6-month OS (71%) rates as compared to JULIET. 6 This was despite the real-world population being older (median age 65 years) and more heavily pre-treated (median 4 prior lines of therapy) than the trial population. Rates of grade 3 or higher CRS (4%) and grade 3 or higher neurotoxicity (5%) were also lower in the real-world patients. 6 Likewise, the CIBMTR data for axi-cel (n=295, median follow-up 6 months) showed comparable ORR (70%) and CR (52%) rates compared to the ZUMA-1 population. 7 Grade 3 or higher CRS was seen in 11% of patients. 61% of patients experienced a neurologic adverse event (grading not reported). 7 Two groups in the United States have also published their real-world axi-cel data. Jacobson et al reported an ORR of 70% and a CR of 50% in their population of patients treated with axi-cel (n=122, median follow-up 10.4 months). 8 63% of the patients in their study would not have been eligible for inclusion in ZUMA-1, with the majority (55%) of that subset being ineligible because they received bridging therapy. CRS and neurotoxicity rates were again comparable to ZUMA-1, with 13% of patients having grade 3 or higher CRS and 35% of patients having grade 3 or higher neurotoxicity. 8 In a second, similar study, Nastoupil et al reported an ORR of 82%, CR of 64%, 12-month PFS of 47% and 12-month OS of 68% in their axi-cel treated population (n=275, median follow-up 12.9 months). 9 Grade 3 or higher CRS (7%) and grade 3 or higher neurotoxicity (31%) were similar to ZUMA-1. 9 This BMT Standard Practice Manual population also included patients who would not have been eligible for ZUMA-1, with the most common reasons for ineligibility being a performance status of ECOG 2 or higher (58 of 275 total patients, 19%), platelets < 75 (11%), or DVT/PE within 6 months (10%). 9 Taken together, these two retrospective reviews, as well as the CIBMTR data, provide encouraging data that suggest that the results seen in JULIET and ZUMA-1 using tisa-cel and axi-cel are similar to those seen in the real world, despite the real-world patients generally being older, more heavily pretreated, and less fit than the trial patients.

# Special Populations:
Multiple retrospective analyses have suggested that outcomes in older patients treated with CAR-T cells are generally favourable. Neelapu et al performed a post hoc subgroup analysis of efficacy and safety in patients <65 vs 65 years of age in ZUMA-1, which demonstrated comparable or better overall response rates (81% in the <65 group, versus 92% in the 65 group), complete response rates (53% vs 75%) and 24-month OS rates (49% vs 54%) in the 65 cohort. 10 Nastoupil et al performed a univariate analysis on a wide range of patient characteristics in their retrospective axi-cel review, including age <60 vs 60. 9 The older subgroup had a statistically significantly improved CR rate compared to the younger group (55% vs 72%, p=0.002), and there were no significant differences in CRS  grade 3 (6% vs 8%, p=0.55), neurotoxicity  grade 3 (30% vs 32%, p=0.71), 12-month PFS (42% vs 51%, p=0.0550), and 12-month OS (66% vs 70%, p=0.52). Patients with an ECOG performance status of 2 or higher had worse outcomes in all metrics (in a univariate analysis), suggesting that fitness may be a more important predictor of outcome than age.
Pre-infusion tumor volume, as well as elevated LDH (above the upper limit of normal), have been associated with poorer response rates and earlier relapse in multiple studies. 9,11 It is not clear whether these factors influence rates of CRS or neurotoxicity.  Results were encouraging in patients with double-hit and double-expressor DLBCL. These patients were under-represented in ZUMA-1, but fortunately, there is ample data available from subsequent retrospective studies. Data with axi-cel from Nastoupil et al included 64 patients (23%) with double/triple-hit lymphoma, and 98 patients (37%) with double expressor DLBCL. 9 There was no significant difference in CR, 12-month PFS, 12-month OS, CRS grade 3, or neurotoxicity grade 3 in these patients as compared to patients without double/triple hit or double expression. 9 Other studies, including the CIBMTR data for tisa-cel, (which included 17 double/triple-hit patients), 6 and another small retrospective study of patients receiving either tisa-cel or axi-cel (which included 10 double-hit and 18 double-expressor patients), 12 both showed similar outcomes in double/triple-hit or doubleexpressor patients compared to patients without these features.
Tisa-cel is not Health Canada approved for the treatment of primary mediastinal B-cell lymphoma (PMBCL), as PMBCL patients were not enrolled in JULIET. Eligible PMBCL patients should therefore be treated with axi-cel. Outcomes in PMBCL patients using axi-cel were generally comparable to those seen in DLBCL patients. 3, Response rates and survival outcomes are difficult to directly compare between tisa-cel and axi-cel given that the key studies enrolled different populations and used different lymphodepletion and bridging strategies. There are no consensus guidelines that suggest using one product over another in a given situation, and at this time, the choice of using tisa-cel or axi-cel for an eligible patient should be left to the discretion of the treating physician. We intend to update these guidelines in the future as additional data becomes available. We also intend to review our own data once a sufficient number of patients have been treated locally in Alberta.
BMT Standard Practice Manual 

# Allogeneic Hematopoietic Stem Cell Transplantation for Aggressive Lymphomas

# Full Intensity (Myeloablative) Conditioning
As opposed to autologous SCT, randomized controlled trials have never been performed to evaluate the role of allogeneic SCT for aggressive lymphoma. Available retrospective data is very difficult to interpret due to alterations in lymphoma classification over the past 20 years and newly identified entities like mantle cell lymphoma were previously grouped with other NHL subtypes. In addition, most series have relatively low numbers of patients, who were very heterogeneous in terms of remission status, disease burden, amount and type of prior therapy. Finally, these patients have received a variety of conditioning and graft-versus-host-disease (GVHD) prophylactic regimens.
Retrospective studies that attempt to compare results of autologous and allogeneic SCT for lymphoma have identified that patients treated with allogeneic SCT tend to have more advanced, heavily pre-treated disease, and more marrow involvement. Despite this selection bias, allogeneic 
SCT seems to result in lower relapse rates than autologous SCT for lymphoma. 1 This may be due to infusion of a tumour-free graft, induction of a graft versus tumour effect, the use of different types of high dose conditioning, or to subtle differences in patient selection that may result in slower progressive types of disease. For example, it is uncommon that aggressive lymphoma patients in second or third relapse would be considered candidates for an allogeneic SCT, therefore, those patients who actually receive this form of late salvage therapy must maintain excellent performance status, and generally maintain chemosensitive, low tumour burden disease. Large transplant registry data demonstrate that high 20-40% TRM from allogeneic SCT, unfortunately offsets the lower relapse rate, and 5year overall survival rates of 35-40% are not superior to those of autologous SCT for aggressive lymphoma. 2 These results seem to be fairly similar regardless of lymphoma subtype, with a little less than one third of patients dying from non-relapse mortality and similar proportion experiencing disease relapse, and a little more than one third of patients achieving long-term diseasefree survival. Somewhat better results have occasionally been reported by single centres, studying small numbers of patients, but of course these reports are far less reliable. Results of allogeneic SCT for aggressive lymphoma after failure of prior autologous SCT are particularly poor; 5 year PFS rates of <10% have been reported. 3 

# Reduced Intensity (Non-Myeloablative) Conditioning
Reduced intensity conditioning (RIC) allogeneic SCT is associated with approximately 10-15% lower TRM, but higher relapse rates compared to traditional full myeloablative allogeneic SCT. 4 Since the beneficial treatment outcome of RIC allogeneic SCT relies upon an immunological graft versus tumour effect, this strategy is questionable for aggressive NHL, particularly for bulky, rapidly progressive disease situations. When these aggressive tumours are treated with RIC allogeneic SCT, the disease often progresses prior to the potential onset of GVDH. Although a few small series suggest brief responses of aggressive lymphoma to DLI or withdrawal of immune suppression post-alloSCT, a graft-versus-aggressive lymphoma effect has never clearly been demonstrated to confer long-term disease control. 5 Successful tumour debulking prior to allogeneic SCT seems to be far more important in aggressive lymphoma than in other histologies to create a favorable effector T-cell to target tumour cell ratio in patients with these fast growing lymphomas.
Despite theoretical concerns regarding RIC allogeneic SCT for aggressive lymphoma, available nonrandomized data suggests at least similar OS rates compared to myeloablative allogeneic SCT. Sorror and colleagues compared outcomes among patients with lymphoma or chronic lymphocytic leukemia given either nonmyeloablative (n=152) or myeloablative (n=68) conditioning. 6 Outcomes were stratified by the SCT-specific comorbidity index. Patients in the nonmyeloablative group were older, had more previous treatment and more comorbidities, more frequently had unrelated donors, and more often had malignancy in remission compared with patients in the myeloablative group. Patients with indolent versus aggressive malignancies were equally distributed among both cohorts. For patients without comorbidities, even after adjustment for pre-transplantation variables, no significant differences were observed between nonmyeloablative and myeloablative SCT cohorts with respect to NRM, PFS or OS. In contrast, patients with comorbidities experienced lower NRM Cesar Freytes and colleagues recently described results of non-myeloablative allogeneic SCT for 267 B-cell NHL patients relapsing after autologous HCT who were reported to the CIBMTR 1997-2006 (median follow-up 37 months). 7 Histological subtypes included DLBCL (56%), follicular (17%), mantle cell lymphoma (27%), and the time from first to second transplant was less than 1 year in 21% of patients, between 1 and 2 years in 30% of patients, and more than 2 years in 49% of patients. In total, 63% were chemosensitive, 31% chemoresistant, and 6% untreated. The graft source was peripheral blood in 78%, and 90% involved unrelated donors. Outcome at 3 years included TRM=42%, progression=36%, and PFS=22%. Causes of death were NHL (29%), infection (19%), MOF (19%), GVHD (14%).There was a lower risk of relapse and death in patients with a KPS90%, >2 years between transplants, use of TBI, and CR at time of SCT.
Most recently, The EBMT reviewed their results of 101 patients with DLBCL who received an allogeneic SCT after relapse from an autologous SCT (MAC=37, RIC=64). 8 The 3-year PFS was 42% and the OS rate was 54%. Non-relapse mortality was 41% for MAC versus 20% for RIC (p=0.05), but relapse rates were higher after RIC, particularly those patients who relapsed less than 1 year postautologous SCT and those who were chemo-resistant. No evidence for GVT effect was seen.
Overall, full and reduced intensity allogeneic SCT for aggressive lymphoma requires further evaluation in well-designed prospective RCTs before the true benefit and role can be fully understood. Only a few conclusions can be drawn based upon currently available data: 1. Relapse rates are lower after myeloablative allogeneic SCT than autologous SCT, although this difference is less than that reported for indolent lymphoma. 2. Treatment-related mortality rates are high, in the range of 20-40%. 3. Some patients who would otherwise have died from their lymphoma achieve long-term survival following allogeneic SCT, and therefore this treatment needs to be considered an option for motivated, well-informed, transplant-eligible patients who are well enough to tolerate this intensive treatment, have relapsed non-bulky chemosensitive disease, and are not candidates for autologous SCT. 4. Data do not demonstrate any improvement in 5-year survival rates with allogeneic over autologous SCT for lymphoma, with the exception of relapsed lymphoblastic and mantle cell lymphomas. 9,10 Patients with these subtypes who present with extensive blood/marrow disease should also be considered for allogeneic SCT in first remission. 11 Allogeneic SCT should also be considered in the situation when a patient is a candidate for an autologous SCT but an adequate autograft could not be collected for the patient. Occasionally, patients who relapse after a prior BMT Standard Practice Manual The role of first remission HDCT/ASCT remains investigational. Three frequently-cited randomized controlled trials have generally followed a similar design where patients either received CHOP-like induction therapy and interferon maintenance or CHOP-like induction followed by HDCT +/-TBI and ASCT. The trials were of modest size (169-401 patients) and allowed crossover HDCT/ASCT at relapse in the control arms. With median follow-up times between 4 and 5 years, one study has shown statistical improvement in overall survival (86 versus 74%) while the other two studies demonstrated improved progression-free survival (65 versus 33% and 59 versus 37%) for HDCT/ASCT over interferon. Because these studies have not consistently shown improved overall survival, involve a potentially toxic, expensive treatment that can be reserved for salvage therapy, and were conducted prior to the routine use of rituximab, HDCT/ASCT is not widely accepted as standard initial therapy for follicular lymphoma.
Treatment of Relapsed/Refractory Indolent Lymphoma  General principles: Generally accepted indications for therapy of indolent lymphoma include:
- Patient symptoms (e.g. fever, night sweats, weight loss, malaise, pain, nausea)
- Significant lymphadenopathy: >7 cm mass, >3 sites and >3 cm - Rapidly progressive, moderate-to-severe splenomegaly - Impending organ compromise (e.g. compression, pleural/pericardial effusions, ascites)
- Cytopenias secondary to bone marrow infiltration - Patient preference because of anxiety and poor quality of life without treatment Patients who do not have at least one of these factors could simply be observed.
Therapeutic recommendations for recurrent follicular lymphoma need to be individualized. No one recommendation is suitable for all patients. Numerous factors need to be taken into consideration before recommending therapy for recurrent follicular lymphoma. Some of these include:
- Patient factors: Age, co-morbidity, symptoms, short versus long-term goals, preservation of future options, reimbursement versus ability to pay for expensive treatments, acceptance of risks/toxicities of treatment option relative to potential benefit (relative risk, progression-free survival, overall survival)
- Disease factors: Sites, grade, transformation, prior therapy, response duration (disease-free interval)
For example, previously healthy patients younger than 65 years who relapsed within 1-2 years of initial chemotherapy have a life expectancy of only 2-4 years, and are probably best managed with HDCT/ASCT or even allogeneic SCT. HDCT/ASCT probably maximizes the length of disease control for all patients younger than 65 years, regardless of length of initial remission, and as such is a reasonable treatment option for those who accept potential risks/toxicities. Conversely, some patients The year of ASCT divided further into the 3 time periods of 1993-1999, 2000-2003, and 2004-2008, reflective of varying rituximab availability in our health region, also showed a significant association with 5 year EFS (38 vs. 56 vs. 64% respectively, p=0.038). Independent predictors of EFS and OS in multivariate analysis were rituximab therapy within 6 months of ASCT and FLIPI score 0-1.
Our results support those of previous publications concerning outcomes of ASCT for relapsed or refractory follicular lymphoma, which report 5-year EFS rates ranging from 44-59% and 5-year OS rates of 63-78%.  One of the largest historical series from the EBMT registry retrospectively analyzed 693 patients with follicular lymphoma treated with ASCT and reported a 10-year PFS rate of 31% with a plateau on the PFS curve. 13 Unfortunately, there are no large randomized trials evaluating ASCT for relapsed follicular lymphoma, however, several trials have demonstrated significantly better PFS for ASCT consolidation compared to interferon for follicular lymphoma patients in first remission. 20 The lack of OS benefit for upfront ASCT in these studies is possibly due to cross-over to ASCT at relapse in the control arms. Available non-randomized data for relapsed follicular lymphoma patients show significantly longer progression-free survival following HDCT/ASCT than from prior therapy within the same patients. A GELA trial reported a 5-year overall survival of 58% for relapsed follicular lymphoma patients treated with ASCT relative to 38% for concurrent controls (p=0.0005), and found that ASCT at first relapse was independently associated with overall survival in multivariate analysis. The only published randomized trial evaluating HDCT/ASCT for relapsed follicular lymphoma was stopped due to poor accrual after only 89 patients were randomized. With a median follow-up of 69 months, the 5-year PFS (55 versus 15%) and OS (70 versus 45%) rates significantly favoured HDCT/ASCT. These results support a role for HDCT/ASCT in the management of selected, relapsed, chemosensitive follicular lymphoma patients. Evidence is emerging that ASCT remains an effective salvage therapy for relapsed follicular lymphoma after rituximab-containing regimens, 20,21 and suggests that rituximab may be beneficial as part of HDT/ASCT salvage therapy. 22,23 Kang and colleagues compared follicular lymphoma patients who had received rituximab prior to ASCT to a group who were rituximab-naive, excluding patients who received rituximab as part of salvage therapy, and found no significant difference in relapse-free survival (RFS) or OS. 21 Ladetto and colleagues reported a study of 136 high risk patients with follicular lymphoma who were randomized to up-front therapy with 6 courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) or rituximab-supplemented high-dose sequential chemotherapy with autografting (R-HDS). 20 They noted a 4-year EFS favouring R-HDS over R-CHOP (61 versus 28%, p<0.001), however OS was similar because 71% of R-CHOP failures underwent salvage R-HDS and 85% achieved a complete remission and 68% achieved 3-year EFS, again demonstrating that HDT can salvage R-chemotherapy failures.
The curative potential of ASCT for follicular lymphoma remains controversial, in part because of a lack of consensus as to the definition of cure for this disease.  Oncologists frequently define cancer cure as a prolonged plateau on a RFS curve after therapy cessation. The plateaus on our EFS curve starting at 6 years and extending to 15 years post-ASCT indicate that a subset of patients may be cured. Several other studies of ASCT for follicular lymphoma have demonstrated similar long-term plateaus on EFS curves, suggesting that relapses are very unlikely to occur after 7-8 year remissions. 5,13,15,16,27,28 Clear evidence of cure post-ASCT for follicular lymphoma is challenging due to the indolent nature of the disease, which requires 5-10 year follow-up to detect late relapses. Many published studies are retrospective, report data on indolent lymphomas with histologies other than follicular lymphoma, include many patients who are heavily pre-treated having failed 3 or more regimens, and report inadequate median follow-up times of less than 5 years, with few patients followed for 10 or more years. If ASCT is to be used as a curative strategy, it should be included as a part of primary therapy or at first relapse. Indeed, Tarella and colleagues reported outcomes for 168 high risk patients with follicular lymphoma who received HDT/ASCT as part of primary therapy and demonstrated that 48% remained in complete remission at a 10 year median follow-up, with a plateau on the disease-free survival curve starting at approximately 8 years. 29 We found that an intermediate or high FLIPI score of 2-5 at the time of relapse/refractory status prior to ASCT was independently predictive of inferior EFS and OS. These results confirm those of Vose and colleagues who reported that a high risk FLIPI score (3)(4)(5) at the time of HDT was predictive of inferior outcome. 18 Two additional studies also reported that an age adjusted International Prognostic Index (aaIPI) of 2 at HDT correlated with poor outcome after ASCT for follicular lymphoma. 17,30,31 In contrast, two studies reported no correlation between FLIPI score and outcome after ASCT for follicular lymphoma, though both analyzed FLIPI at diagnosis rather than at ASCT. 5,28 In our analysis, an intermediate to high risk FLIPI score at diagnosis also had no predictive value for survival post-ASCT.
BMT Standard Practice Manual Retrospective studies have demonstrated that rituximab improves outcomes when used prior to HDT-ASCT for relapsed follicular lymphoma. 17,19,22,30 The only phase III trial to evaluate the role of rituximab in the setting of ASCT for follicular lymphoma is the EBMT LYM1 study, which investigated the value of in-vivo purging with rituximab 375 mg/m 2 weekly for 4 cycles prior to stem cell collection and the value of maintenance rituximab every 3 months for 2 years post-ASCT. 32 This study randomized 280 patients with follicular lymphoma in a 2x2 design, and showed no improvement in PFS with in-vivo purging (5-year PFS 54.3 versus 47.8%, p=0.20), but improvement in PFS with maintenance rituximab (58.8 versus 42.6%, p=0.02). We also found no evidence that rituximab-based mobilization improved EFS over chemotherapy alone; however, this result is confounded by the use of rituximab with re-induction therapy prior to mobilization for many patients. The benefit of rituximab pre-ASCT may be due to an in-vivo purging effect on the autograft. 17,19 Arcaini and colleagues demonstrated this purging effect by showing that none of their patients' stem cell harvests had detectable minimal residual disease using polymerase chain reaction (PCR) amplification of the Bcl-2/IgH rearrangement after receiving a rituximab-containing regimen. 19 Absence of minimal residual disease was demonstrated to lead to an improvement in PFS, a finding confirmed by several groups. 16,17,19,27 Our early treatment-related mortality rate of 2%, and secondary AML/MDS rate of 4% compare favourably with other reports of HDT/ASCT for follicular lymphoma, but are still of concern. These serious adverse events caution against using HDT/ASCT as a part of initial remission consolidation. Other series report rates of secondary malignancies as high as 16-21% at 10 years with about half being fatal; 5,28 though this rate may be lower with HDT regimens that exclude total body irradiation. 13,23 The patients in our cohort who developed secondary AML/MDS had all received prior fludarabine or chlorambucil, and total body irradiation in the HDT regimen. Avoidance of these exposures may decrease the incidence of secondary AML/MDS for this patient population.
BMT Standard Practice Manual 

# Allogeneic Transplantation for Follicular and Other Indolent Lymphomas
Despite prolonged OS from diagnosis, patients with indolent B-cell NHL are rarely cured by conventional chemotherapy. 1 Following relapse, most patients live with the presence of disease and intermittent toxicity from repeated courses of therapy until their death, often within 5 years of relapse. 2 As such, many otherwise healthy individuals prefer to maximize the chance of prolonged PFS with high dose therapy and HSCT;  a result possibly improved when rituximab is used with stem cell mobilization or transplantation. 8,9 It must be acknowledged, however, that most SCT data are retrospective, and subject to selection bias. Compared to autoSCT outcomes, CIBMTR data suggest that alloSCT is associated with significantly lower relapse rates but similar OS rates due to much higher TRM from GVHD and opportunistic infections. 10,11 Specifically, the CIBMTR reported results on 904 patients undergoing alloSCT (176), purged autoSCT (131), or unpurged autoSCT (597) for follicular lymphoma, showing that 5-year TRM rates were 30%, 14%, and 8%, 5-year relapse rates were 21%, 43%, and 58%, and 5-year OS were 51%, 62%, and 55%, respectively, with no association between GVHD and lymphoma relapse after alloSCT. 10 There are no data from large BMT Standard Practice Manual Data from the CIBMTR suggest that a second autoSCT is feasible and can confer long-term benefit in some patients, usually those who relapse more than one year after the prior autoSCT. 12 It is also possible to perform an alloSCT after prior autoSCT failure, although CIBMTR results suggest 3 and 5 year PFS rates of only 20 and 5%, respectively. 13 CIBMTR data showing significantly lower rates of grades III-IV acute GVHD and improved PFS for 179 patients who received rituximab within 6 months of alloSCT compared to 256 patients who did not receive prior rituximab. 14 TRM may potentially be further reduced with non-myeloablative conditioning (NST), also called reduced intensity conditioning (RIC), 15 however data derived from large numbers of patients receiving NST reported to the CIBMTR demonstrate 1 year TRM rates slightly over 20%, and higher relapse rates than myeloablative alloSCT. 16 Quality of life (QOL) studies in the SCT setting tend to report that early impairments in QOL largely return to pre-SCT levels by day 100, over half of patients report good to excellent QOL one year post-SCT, autoSCT patients tend to recover faster than alloSCT, and that reduced QOL and impaired functional status post-alloSCT is most strongly associated with the presence of chronic GVHD. 17,18 

# Autologous SCT for Hodgkin Lymphoma
Two randomized trials support the role of high-dose therapy (HDT) and ASCT over conventional dose salvage therapy with mini-BEAM (carmustine, etoposide, cytarabine, melphalan) or dexamethasone-BEAM in relapsed/refractory Hodgkin lymphoma, 3,4 although optimal re-induction and HDT regimens are unknown.  A commonly used salvage regimen for Hodgkin lymphoma in Canada is GDP (gemcitabine, dexamethasone, cisplatin). Kuruvilla and colleagues from Toronto retrospectively compared the outcomes of 68 Hodgkin lymphoma patients treated with either GDP or mini-BEAM as salvage therapy, followed by HDT/ASCT in responding patients. 14 The response rate to GDP prior to ASCT was similar to mini-BEAM at 62% and 68%, respectively, however, the PFS at 1.5 years was superior with GDP (74% vs. 35%). Moccia and colleagues from the British Columbia Cancer Agency recently presented results of salvage GDP for 83 Hodgkin lymphoma patients whose characteristics included 82% International Prognostic Score (IPS) 0-3, 88% first salvage, 36% refractory. Of the 67% patients who had response assessment available, 7% achieved CR/CRu, 64% PR, and 69 pts (83%) proceeded to HDT/ASCT. With a median follow-up of 30 months from starting GDP, 2-year PFS was 58%. 15 Recently, Josting and colleagues published the results of the HDR-2 randomized controlled trial in which patients responding after 2 cycles of DHAP (dexamethasone, cytarabine, cisplatin) were randomized to either standard BEAM-ASCT or sequential high dose therapy (SHDCT: cyclophosphamide, methotrexate, etoposide) before BEAM-ASCT. 16 Patients randomized in this study were chemosensitive and 60% had relapsed after an initial remission duration of over 1 year. Nevertheless, the 3-year freedom from treatment failure rate was only 62%, and was similar between the arms.
Calgary previously reported a 5-year event-free survival (EFS) rate of approximately 50% for 23 patients with relapsed/refractory Hodgkin lymphoma who were treated with single agent high-dose melphalan and ASCT. 17 This rate is similar to that reported for multi-agent high-dose chemotherapy regimens. 3,4,18,19  Results of DICEP compare favourably to reports of other salvage regimens, which tend to report ORR below 75% and 5 year PFS rates below 50%. The ORR with DICEP was 86% despite the fact that that response was assessed only 4-5 weeks after a single cycle of salvage therapy, and without the use of PET which may have upgraded some PRs to CRs. Perhaps the most encouraging results were seen for primary refractory disease patients. Prior reports of high dose therapy/ASCT for refractory Hodgkin lymphoma include a 3-year PFS rate of 38% from the Autologous Bone Marrow Transplant Registry, and 5-year freedom from second failure rate of 31% from the German Hodgkin Study Group. 20,21 Most studies suggest that the length of initial remission duration is associated with outcome of salvage high dose therapy/ASCT,  however, this is not a universal finding. 24 In our study, however, initial time to progression failed to impact either PFS or OS with a 5-year PFS rate of 57% for refractory Hodgkin lymphoma, suggesting that DICEP-high dose melphalan/ASCT overcomes relative chemo-resistance and provide superior outcomes in patients with primary refractory disease.

# Second Hematopoietic SCT for Hodgkin Lymphoma
Smith and colleagues from the CIBMTR reported a 5-year PFS rate of 30% for patients with either Hodgkin lymphoma (n = 21) or non-Hodgkin lymphoma (n=19) receiving a second ASCT after relapse following a prior ASCT, suggesting that a second ASCT can possibly induce long term disease control for some patients who are not cured by prior high dose therapy. 25 In another study, a 5-year OS rate of 46% was reported using tandem transplantation in poor prognosis relapsed or refractory Hodgkin lymphoma patients. 26 Clear evidence, however, must await randomized controlled trials, which have not evaluated this strategy of tandem high dose therapy for relapsed Hodgkin lymphoma.
Allogeneic SCT for Hodgkin lymphoma has been reported to confer a 5 year PFS in approximately 20-35% of patients. 27 Patients who achieve good outcomes generally have chemosensitive disease that relapsed more than 1 year post-autoSCT. Reduced intensity conditioning allogeneic SCT for Hodgkin lymphoma patients relapsing after autologous transplantation was reported by Sarina and colleagues from the GITMO group in 2008. 28 In this study of 132 patients with a median age of 30 years (range 17-62), 75 patients were found to have a SCT donor and 68 (90%) underwent an allogeneic SCT, including 36 matched related donors (52%), 23 matched unrelated donors (33%), and 6 haploidentical family donors (9%). The most common high dose chemotherapy regimen was thiotepa, cyclophosphamide, and fludarabine; GVHD prophylaxis consisted of methotrexate plus cyclosporine, except for haploidentical-SCT. Seven patients with donors did not receive allogeneic SCT because of progressive disease. The cohorts of donors versus no donors were well balanced, including relapsing less than 6 months from autologous SCT. The results are shown in the table The section on the stem cell graft has been removed from these guidelines and transferred to the section on "Donor Management, including Stem Cell Mobilization".

# Allogeneic Stem Cell Transplantation for Lymphoma
General Comments  Potential benefits of allogeneic over autologous SCT for lymphoma have not been evaluated by randomized controlled trials. As such it is difficult to determine when this more expensive and toxic treatment should be recommended. IBMTR and EBMT registry data do not demonstrate any improvement in 5 year survival rates with allogeneic over autologous SCT for lymphoma, with the exception of relapsed lymphoblastic and mantle cell lymphomas. Patients with these subtypes who presented with extensive blood/marrow disease should also be considered for allogeneic SCT in first remission. Allogeneic SCT should also be considered for multiply relapsed indolent lymphoma (2 nd or 3 rd relapse), or in the situation when a patient is a candidate for an autologous SCT but an adequate autograft could not be collected for the patient. Occasionally, patients who relapse after a prior autologous SCT could be considered for an allogeneic SCT, especially for mantle cell or indolent lymphomas, and occasionally for Hodgkin lymphoma.  In Calgary, we analyzed 115 patients with refractory/relapsed DLBC or large T-cell non-Hodgkin lymphoma who received DICEP salvage therapy. Of these patients, 104 (90%) proceeded to HDCT/ASCT. Initial time to relapse < 1yr, elevated LDH, ECOG 2-4, and aaIPI=3 were more common in the 11 patients who did not proceed to ASCT. For example, of the 25 patients with aaIPI=3, only 17 (68%) proceeded to ASCT compared with 87 of 90 patients (97%) with aaIPI=0-2. We also compared the results of the 104 patients who received DICEP then HDCT/ASCT with the other 44 Calgary patients who received HDCT/ASCT during the same time period (1995-2009) but did not receive DICEP. Clinical factors more common in DICEP than no DICEP groups included:
- age >60 13.5% vs. 40.9% (p=0.0002)
- TTP<1yr 72.1% vs. 47.7% (p=0.004)
- refractory 29.8% vs. 6.8% (p=0.002)
- bulk >10cm 24.3% vs. 9.1% (p=0.042)
Despite generally worse prognostic factors in the DICEP group, PFS rates were not significantly different between the groups (logrank p=0.11).     

# HDCT/ASCT for Relapsed/Refractory Aggressive Histology Non-Hodgkin

# Myeloma and Amyloidosis
Presented by: The Myeloma Group Summary 1. For symptomatic multiple myeloma, an autologous stem cell transplant (ASCT) should be offered to patients who are 65 years old, without significant co-morbidities, and have achieved at least partial response after induction chemotherapy.
- For individuals between ages 65 and 70 years, ASCT will be considered if the IMWG Frailty index is 70 years.
- We recommend an early referral (after 2 cycles of induction chemotherapy) to the transplant team for ASCT consideration 2. Collecting enough stem cells for 2 transplants (for salvage, tandem or boost) is recommended but will be discussed on a case by case basis - Adequate stem cells will be collected for 2 ASCT in patients 60 years. - Other considerations include 1) patient factors, 2) disease factors, 3) evolving myeloma therapies, and 3) local resource factors 3. The preferred conditioning chemotherapy for ASCT is Melphalan 200mg/m 2 - The use of Busulfan with melphalan conditioning is reasonable - Dose reductions of melphalan is reasonable in those with renal dysfunction and/or frailty. 4. The preference is to offer an upfront ASCT post-induction as opposed to an ASCT on relapse. 5. Offering a second ASCT on relapse is reasonable if the disease has been in control for at least 2 years (no maintenance) and at least 4 years (with maintenance). 6. Tandem ASCT is not recommended. However, for patients with high risk disease that may benefit from this approach, tandem ASCT will be considered on a case-by-case basis. 7. The use of consolidation therapy post-ASCT is recommended in patients with high risk disease and in patients who achieved 30 ml/min per 1.73 m2 unless on dialysis, - New York Heart Association class 45%, systolic blood pressure >90 mm Hg (standing), and - Lung CO diffusion capacity >50%. 11. Induction chemotherapy for patients with AL amyloidosis should be recommended for patients with >10% monoclonal plasma cells in the bone marrow at presentation. 12. A salvage ASCT for AL amyloidosis will be considered on a case-by-case basis.

# Symptomatic Myeloma

# Background
Multiple myeloma is a chemotherapy-responsive tumor that demonstrates significant dose-response effects. The availability of increased and superior therapeutic options has led to improvements in depth and duration of response. Ultimately, this translates to better Progression-Free Survival (PFS), Overall Survival (OS) and Health related Quality of Life (HRQOL). A more thorough discussion on myeloma care can be found within the AHS Myeloma Guidelines.
Hematopoietic stem cell transplantation involves the use of high-dose chemotherapy followed by an infusion of either autologous, allogeneic, or syngeneic stem cells. Data from the CIBMTR, suggests improvements in myeloma outcomes with autologous stem cell transplantation (ASCT) 1 . In historical randomized controlled trials (RCT), the use of high-dose chemotherapy with ASCT to standard induction protocols demonstrates improved PFS, OS and HRQOL (Table 1). 

# Rationale for use of autologus stem cell transplantation
Autologous stem cell transplantation (ASCT) represents a significant advancement in care for patients with myeloma, where the chemotherapeutic options were historically limited. Multiple randomized controlled trials (RCT) have demonstrated the superiority of ASCT over standard care/conventional cytotoxic chemotherapy -improved depth of response, PFS/EFS and OS (Table 1). A meta-analysis of these historic studies supports the use of ASCT with improvements in PFS, but not OS 8 . Additionally, one RCT demonstrates better HRQOL as evaluated by a composite endpoint of a longer period without symptoms, treatment, and treatment toxicity (TwisTT) 9 .
With the availability of newer chemotherapeutics such as proteasome inhibitors and immunomodulatory agents, they have been incorporated into myeloma care 10 . Such combinations have led to deeper and more durable responses either in induction, consolidation, and maintenance therapy 11,12 . Given these improved outcomes, many have challenged whether ASCT still has a role in myeloma care. Table 2 summarizes more recent Phase III RCTs performed in the current era of chemotherapeutics for induction. These studies have been variably subject to pooled analyses and meta-analyses demonstrating ACST's value 13,14 . More recently, the Determination study led by Richardson et al. compared 8 cycles of lenalidomide, bortezomib and dexamethasone (RVD) to 3 cycles of RVD, ASCT with 2 cycles of RVD consolidation. Subsequently, both groups received lenalidomide maintenance. With a median follow-up of 76 months, they demonstrate a median PFS that favors the ASCT group (46.2 vs. 67.5 months) affirming the continued role of ASCT. Collectively, these studies suggest that ASCT consistently improves responses, PFS and OS. ASCT continues to be a key intervention in the current era of chemotherapeutics.

# Timing of ASCT
The optimal timing of ASCT has been debated -should it be offered after successful induction therapy or on relapse? The only Phase III RCT was performed prior to the availability of novel agent, where it demonstrates similar survival, but patients undergoing early ASCT had superior HRQOL as measured by TwisTT 9 . In the current therapeutic era, there are several single institution observational studies compared early vs. delayed ASCT  and systematic reviews 14  cycles of RVD induction with ASCT vs. 8 x RVD. In the 8 x RVD group, 79% of symptomatic patients received a salvage (delayed) ASCT 18 . This study may allow an indirect comparison of early vs. delayed ASCT. Both PFS and HRQOL was favored in the patients receiving early ASCT in the IFM-DFCI study 18 . More recently, patients participating in phase III EMN02/HO95 study who were randomized to upfront ASCT were compared (not randomized) to those who received ASCT at the time of progression after primary randomization to VMP 24 . After a median follow-up of 85 months in the upfront auto-HSCT group with a median follow-up of 51 months in the delayed auto-HSCT group, the median PFS2 rate was 55% vs 32% (HR, 0.52; 95% CI, 0.40-0.66; p < 0.0001) respectively. Moreover, median OS was not reached in the upfront auto-HSCT group vs 81 months in the delayed auto-HSCT group, with OS rates of 69% vs 58% (HR, 0.68; 95% CI, 0.51-0.93; p = 0.0164). Taken together, it is ideal that ASCT be considered upfront in patients who are eligible. However, it is reasonable to delay ASCT due to personal and/or psychosocial reasons given similar OS. It must be recognized that by deferring an ASCT may mean that in the future, an ASCT may not be possible or warranted. This risk has been estimated to be around 10% from a single institution study 25 . Moreover, it may be preferable to strongly consider an upfront ASCT in individuals who are deemed high risk by disease presentation, cytogenetics, or gene expression profiling.

# Eligibility for ASCT Chronologic Age:
Given that most RCTs evaluate patients who are 65 years for ASCT, this constitutes the highest level of evidence for practice. However, there have been numerous observational studies that suggest that ASCT is feasible in patients > 65 years with careful selection  . In addition, there have been movements to consider physiologic age as opposed to chronologic age 31 . As such, it is reasonable to consider ASCT in patients >65 with careful attention to comorbidities and assessments of frailty. However, given the advancements in myeloma therapeutics, the relative value of ASCT in older patients will likely decrease. For instance, the use of Daratumumab/Lenalidomide and dexamethasone (DRd) can provide a 5-year PFS rate of 52.5% 32 . 

# Depth of Response:
In general depth of response pre-ASCT correlates with post-ASCT outcomes 33 . However, a historic registry study at IBMTR suggests deepening responses beyond partial response (PR) did not translate to better OS. More recent data from the CIBMTR suggest that patients achieving less than a PR to initial induction therapy, including with novel agent combinations, additional pre-ASCT salvage chemotherapy improved the depth of response and pre-ASCT disease status but was not associated with survival benefit 34 . Additionally, patients with refractory myeloma (<PR) might still derived benefit from ASCT. Notably, current induction therapies (e.g., CYBORD or RVD) do not generally include cytotoxic therapy -meaning that a less than responsive disease might still derived benefit from ASCT where high dose melphalan is used for conditioning 35 .
In the "novel therapy" era, the MRC XI 36 evaluated whether there is value in deepening responses prior to ASCT. They randomized patients who only achieved a MR or PR after immunomodulatory based triplet therapy to receive either no additional therapy or additional therapy with bortezomib, cyclophosphamide and dexamethasone (CYBORD). The additional therapy improved the pre-ASCT responses (PR improved to VGPR in 41% of evaluable cases) and translated to improved PFS (55 months vs. 30 months, P=0.0003), but no differences in OS.

# Stem cell mobilization See AHS BMT guidelines section: Donor Management, Mobilization
Should we be collecting enough stem cells for 2 ASCTs: Table 4 illustrates ASCTs performed in Calgary from 2010, including the proportion of 2 nd and 3 rd ASCT (planned tandem, delayed ASCT or stem cell boost).
Considerations for collection amount include: 1) patient factors such as age, co-morbidities, 2) disease factors such as high-risk disease, 3) evolving myeloma therapies, and 3) local resource factors. Taken together, collecting for 1 or 2 ASCT will discussed on a case-by-case basis.  
0 1 0 2 2 9 7 2 3 1 6 7 2 nd ASCT 3 0 1 1 5 6 6 5 7 3 2 5 65 years 3 0 1 1 4 5 5 3 4 2 1 4 >65 years 0 0 0 0 1 1 1 2 3 1 1 1 3 rd ASCT 0 0 0 0 2 0 0 1 0 0 1 0 65 years 0 0 0 0 2 0 0 1 0 0 0 0 >65 years 0 0 0 0 0 0 0 0 0 0 1 0

# Conditioning regimen
The current standard for conditioning is Melphalan 200mg/m 2 following a RCT demonstrating that Melphalan 200mg/m 2 (Mel200) was superior to Melphalan 140mg/m 2 (Mel140) with 8 Gy Total Body Irradiation 37 . A large database study from EBMT suggests that Mel200 may be preferable to Mel140 to patients who do not achieve a PR post-induction chemotherapy. In contrast, patients appear to do just as well with Mel140 in those with VGPR post-induction chemotherapy 38 .
More recently, Roussel et al. compared Mel200 with Mel200+Bortezomib. In this RCT carried out by the IFM, the combination of Mel200+Bortezomib did not result in superior depth of response, PFS or OS 39 . Additionally, Bashir et al. evaluated the combination of Mel140+Busulfan 130mg/m 2 vs. Mel200 in a RCT with the combination therapy associated with an improved PFS (65 months vs. 44 months) 40 . Interestingly, this trial showed an improvement in PFS with the Bu-Mel conditioning regimen in patients with newly diagnosed myeloma with HR cytogenetics, where the median PFS was 44.7 months and 25.7 months in the Bu-Mel and Mel arms, respectively (P = .044) 41 . A meta-analysis of 10 observation studies with a total of 2855 patients examined the use of Bu-Mel conditioning compared with Mel200 alone. Bu-Mel conditioning correlates with longer PFS (HR 0.77; p=0.0002) but similar OS (HR 1.08; p=0.35) 42 .
The dose of melphalan should be reduced to 140mg/m 2 in individuals with renal dysfunction or on dialysis  . Further, consideration could be given to a 140mg/m 2 melphalan dosing in those who >65 years with deemed frailty  . 

# Role of tandem ASCT Tandem ASCT with historic induction chemotherapy:
A tandem ASCT can be defined as a pre-planned second ASCT within 6 months of the first ASCT, where the goal is avail of additional high dose melphalan to achieve a deeper hematological response.
There has been several RCTs comparing tandem with single ASCTs prior modern induction chemotherapy 47, . These older studies demonstrate that tandem RCTs can improve either EFS or PFS with only one demonstrating OS advantage limited to the subgroup of patients not achieving VGPR after the 1 st ASCT 49 . Two meta-analyses would confirm these observations 52,53 .  

# Tandem ASCT with modern induction chemotherapy:
More recently, a post-hoc analyses using pooled data from 3 independent Phase III RCTs was performed to elucidate the potential value of tandem ASCT 54 . All 3 RCTs utilized bortezomib-based induction regimen. There was a significant improvement in the median PFS and 5-year OS in favor of tandem ASCT. This benefit was more apparent in patients with high-risk cytogenetics such as t(4;14) and/or deletion 17p who had not achieved a CR after induction therapy (70% vs. 17%). Additionally, these results were further affirmed with their 10 year follow-up data where patients with ISS stage II+III, high-risk cytogenetics and failure to achieve CR benefitted from a tandem ASCT approach 55 .
These findings were also echoed by the preliminary findings in the EMN02/HO95 MM study 17 , where there was a significant improvement in the 3-year PFS (73% vs. 64%) and 3-year OS (89% vs. 82%) in favor of tandem ASCT compared to single ASCT. The superiority of a tandem ASCT was again evident in patients with high-risk cytogenetics in both 3-year PFS and OS. In this study, most patients received bortezomib based induction (i.e., no lenalidomide).
In contrast, the BMT-CTN 0702 STAMINA study 56 did not demonstrate any difference between patients (after initial ASCT who either received a 1) tandem ASCT followed by maintenance lenalidomide, 2) 4 cycles of consolidation (lenalidomide, bortezomib and dexamethasone (RVD)) followed by maintenance lenalidomide, or 3) maintenance lenalidomide alone. Of note, most patients in this study received RVD induction therapy prior to initial ASCT. 

# Consolidation post-ASCT
The goal of consolidation therapy post-ASCT is to improve and augment responses -to suppress residual disease. There have several RCTs suggesting that consolidation can deepen responses and prolong PFS. However, its effect on OS is less clear. Indeed, the above mentioned BMT-CTN 0702 STAMINA study 56 did not demonstrate benefit of consolidation therapy. In contrast, preliminary data from the EMN02/HO95 MM study 57 suggest a PFS benefit with 2 cycles of lenalidomide, bortezomib and dexamethasone (VRD) consolidation (p=0.013) without OS benefit (p>0.05). 

# Maintenance post-ASCT
A typical maintenance therapy is low dose with limited toxicity administered over a prolonged period to deepen responses and/or maintain responses. Thalidomide was historically for maintenance therapy post-ASCT with improvements in depth of responses, PFS and possibly OS. This came at a cost of clinically significant peripheral neuropathy and therapy related fatigue. Interestingly, thalidomide maintenance therapy has been associated with worse outcomes in patients with high-risk cytogenetics.
Maintenance with lenalidomide has been considered standard of care following the publications by CALGB 59 and IFM 60 . Both studies demonstrate improvements in PFS but only the CALGB study demonstrates improvements with OS on lenalidomide maintenance. Both the GIMEMA 15 and Myeloma IX 36 study would confirm the benefit of maintenance lenalidomide on PFS. The results of these studies have been subject to systematic reviews/meta-analyses which confirms the efficacy of maintenance lenalidomide  .
The duration of maintenance therapy with lenalidomide has been subject to some discussion. In the IFM/DFCI2009 study 18   The effect of maintenance bortezomib post-ASCT has also been evaluated. The HOVON-65/GMMG-HD4 study suggest that patients with del 17p might benefit from a proteasome inhibitor maintenance 66,67 . More recently, the TOURMALINE MM3 study 68 evaluated ixazomib maintenance post-ASCT compared to placebo. After a median follow-up of 31 months with 54% of PFS events, there was a 28% reduction in the risk of progression/death, corresponding to a 39% improvement in PFS with ixazomib vs placebo (median 26.5 vs 21.3 months; hazard ratio  0.72; 95% CI: 0.582, 0.890; p=0.002). In a landmark analysis from ASCT, PFS was 30.7 vs 24.9 months (HR 0.684; 95% CI: 0.551, 0.848; p<0.001).  

# Role of second ASCT for salvage therapy
Given that most if not all patients will relapse, a second ASCT can be considered as salvage treatment. There has been 1 RCT that evaluates the use of 2 nd salvage ASCT vs. conventional care, demonstrating that a 2 nd salvage improves PFS but not OS 71 . In contrast, there have been numerous observational studies that support the use of a 2 nd salvage ASCT  . Given that the duration of response with a 2 nd ASCT will be shorter than the 1 st ASCT, an arbitrary cutoff of at least 2 years from the 1 st ASCT before 2 nd ASCT should be considered. However, the routine use of consolidation and maintenance may change this duration of response "cutoff". 

# Role of allogeneic transplant
Evidence for a graft-versus-myeloma effect has been weak. Allogeneic transplants (myeloablative) are associated with significant treatment related toxicity with unclear long-term benefits. Given these toxicities, reduced intensity conditioning (RIC) allogeneic transplants have been advocated to mitigate concerns surrounding transplant related mortality. There have been several RCTs and quasi-RCTs that have evaluated tandem ASCT vs. ASCT followed by RIC allogeneic transplants  . In general, there is a lack of meaningful benefit with an ASCT-RIC allogeneic transplant approach to myeloma care 85,86 . Allogeneic transplant in relapsed disease is poorly tolerated with marginal effectiveness over other available therapies 85,86 .  

# Systemic AL Amyloidosis
Background Systemic immunoglobulin light chain amyloidosis is a protein misfolding disease caused by the conversion of immunoglobulin light chains from their soluble functional states into highly organized amyloid fibrillar aggregates that lead to organ dysfunction 87 . Light-chain (AL) amyloidosis is the most common form of systemic amyloidosis, accounting for 70% of patients with amyloidosis 88 . AL amyloidosis (historically referred to as primary amyloidosis) is an uncommon disorder and its exact incidence is unknown. However, in the USA the incidence ranges from 9-14 cases per million person years 89 . AL amyloidosis is a disease of the elderly with a median age at diagnosis of 63 years 90 .
There is a male predominance, with men accounting for 55% of cases 91 . AL amyloidosis occurs in all races and geographic locations, but data are limited regarding the incidence of AL amyloidosis across different ethnic groups.
Patients with a new diagnosis of AL amyloidosis should be referred to a center with expertise in the treatment of this entity, especially if considering for autologous stem cell transplantation (ASCT).

# Autologous Stem Cell Transplantation (ASCT):
Most AL amyloidosis patients are not eligible for ASCT due to the presence of significant comorbidities. Early studies reported high mortality rates during ASCT for AL patients, however, due to improved supportive care and careful patient selection, the mortality in ASCT has decreased significantly 92 .
A recent report by the Mayo Clinic showed an early mortality rate (before day 100) of only 1.1% when Mayo stage III patients are excluded from transplant 93 . In addition, a recent long-term report on 20 years of experience with ASCT for AL amyloidosis at the Mayo Clinic Rochester highlighted the benefits of supportive care and patient selection in the setting of ASCT for AL Amyloidosis 94 . In brief,  ). The median age for the entire cohort was 59 years, with patients in cohort 3 being slightly older than those in the other two cohorts (60 v 58 v 54 years for cohorts 3, 2, and 1, respectively; P < .001). More patients received pre-transplantation therapy in cohort 3 compared with earlier time periods (49% v 38% v 42% for cohorts 3, 2, and 1, respectively; P = .02). Hematologic response was higher in cohort 3 (84% v 79% v 69% for cohorts 3, 2, and 1, respectively; P = .002). Median overall survival for the entire cohort was 122 months and improved over time (not reached v 120 months v 75 months for cohorts 3, 2, and 1, respectively; P < .001). Treatment-related mortality declined over time (2.4% v 8.6% v 14.5% for cohorts 3, 2, and 1, respectively; P < .001).
The improved survival and markedly reduced treatment-related mortality in eligible patients indicate that this will remain an important first-line option even in the era of treatment approaches Eligibility criteria ASCT was reported in 1996 as a form of treatment for AL amyloidosis 95 . High-dose dexamethasone was introduced later in 1997 96 . Since then, multiple advances in the treatment (novel agents) and supportive care have been developed. The first randomized clinical trial on AL amyloidosis led by the MAG and IFM group reported that the outcome of treatment of AL amyloidosis with high-dose melphalan plus ASCT was not superior to the outcome with standard-dose melphalan plus dexamethasone 97 . However, no cardiac biomarker selection was made on those patients and 29 centers were included for the study.
Requirements for safe ASCT currently include 92,93,98-100 :
- Age 30 ml/min per 1.73 m2 unless on dialysis, 5. New York Heart Association class 45%, systolic blood pressure >90 mm Hg (standing), and 6. Lung CO diffusion capacity >50%.
Non-transplant candidates can be offered melphalan-dexamethasone or cyclophosphamidebortezomib-dexamethasone. Daratumumab appears to be highly active in AL amyloidosis. Currently, a clinical trial incorporating daratumumab to CyBorD is ongoing. Antibodies designed to dissolve existing amyloid deposits are under study. So far, only one amyloid removal antibody trial is ongoing (CAEL 101). 

# Induction and stem cell collection
One of the first issues to consider for AL patients eligible for ASCT is the stem cell collection process 101 . Patients with AL commonly suffer from kidney and heart involvement and during the collection process often tend to accumulate fluids during filgrastim (granulocyte colony stimulating factor) mobilization 102 and thus, fluid balance should be meticulously followed and maintained.
The second issue in transplantation of AL amyloidosis patients is whether an induction before SCT improves outcomes. A single-center, prospective randomized trial reported on the role of induction (two cycles of bortezomib and dexamethasone) versus no induction in 56 AL amyloidosis patients. Overall hematologic (ORR) and organ response rates (OR) in the whole cohort after ASCT were 77% and 58%. The ORR and OR in the bortezomib pretreated group were 92% and 75% vs. 69% and 54% in the group that received no pretreatment. The median time to maximum hematologic response after ASCT was reduced in the group that received bortezomib induction (3 vs. 14 months). Overall cardiac response rate was 60%; 100% in patients pretreated with bortezomib and 43% in those without induction treatment. With a median follow-up of 2.9 years, the 3-year progression-free and overall survival rates in the entire cohort were 66% and 73% and in those with cardiac involvement, 73% and 80% 103 .
In a study from the MDACC the type of induction therapy and its impact on the outcome of autologous hematopoietic stem cell transplantation in AL was evaluated in 128 patients. The patients were divided into 3 groups: no induction (20 patients), conventional chemotherapy-based induction (melphalan and steroids; 25 patients), and IMiD/proteasome inhibitor (PI)-based induction (83 patients). Overall, the hematological response on day 100 was highest in the IMiD/PI group, and organ response at 1 year was highest in the conventional chemotherapy-based induction. The 2-year PFS rates were 67, 56, and 73% in the no induction, CC, and IMiD/PI groups, respectively, and OS rates at 2 years were 73, 76, and 87%, respectively 104 .
Among 415 AL patients, 35% had induction prior to ASCT at the Mayo Clinic 105 . Post-ASCT hematologic CR plus VGPR rates were significantly higher in those with baseline BMPC  10% compared to BMPC >10% (58% versus 40%, P = 0.0013). Significant risk factors for lack of attainment of CR included attenuated dose melphalan conditioning, baseline BMPC > 10%, no induction, and male gender. The 5-year OS for the entire group was 65%. Mayo Clinic patients eligible for ASCT that have bone marrow plasma cells lower that 10% are sent directly to ASCT.
We recommend induction therapy for those with >10% BMPC's as outcomes appear to be better.

# Conditioning
In immunoglobulin light-chain (AL) amyloidosis, the depth of hematologic response to treatment is associated with improved survival and organ responses. A recent clinical trial using bortezomib in induction and in conditioning with melphalan before ASCT for AL amyloidosis was reported by the Boston University (BU) group 106  77 months in 35 patients enrolled showed a hematologic complete response and very good partial response (VGPR) of 100% (27 of 27) of the evaluable patients at 6 months post-ASCT. Four patients (15%) had hematologic relapse at a median of 42 months, and 1 patient (3.7%) had organ progression despite maintaining a VGPR at 37 months. The median overall survival and progressionfree survival have not yet been reached at the time of the report. Renal and cardiac responses occurred in 65% and 88%, respectively, at 5 years post-ASCT. The median time to renal and cardiac response was 12 months and 6 months, respectively.
In conclusion, incorporating bortezomib into induction and conditioning yielded durable hematologic responses of AL amyloidosis, with corresponding organ responses and prolonged survival. At our center bortezomib and melphalan as well as melphalan are the recommended conditioning regimens for transplantation in AL amyloidosis. It should be noted that recent data from the IFM in MM showed that Bor-HDM did not improve clinical outcomes or degree of response 107 and thus this conditioning regimen has been discouraged in MM, no data is available in this regard for AL amyloidosis.

# Consolidation
It has been reported that bortezomib in combination with dexamethasone (BD) followed by ASCT can significantly improve both the hematological and organ response rates of AL amyloidosis patients compared to ASCT alone.
An initial phase II trial using bortezomib and dexamethasone (BD) as consolidation was reported by Landau et al. 107 . Forty untreated patients with renal (70%), cardiac (65%), liver/gastrointestinal (15%) or nervous system (13%) AL were assigned MEL 100, 140 or 200 mg/m 2 based on age, renal function, and cardiac involvement. Hematological response was assessed at 3 months post stem cell transplant (SCT); patients with less than complete hematological response (CR) received BD consolidation. Four patients with advanced cardiac AL died within 100 days of SCT (10% treatmentrelated mortality). Survival at 12-and 24-months post treatment start was 88 and 82% overall and was 81 and 72% in patients with cardiac AL. At 3 months post SCT, 45% had  partial response (PR) including 27% CR. Twenty-three patients received consolidation and in 86% response improved; all patients responded in one cycle. At 12 and 24 months, 79 and 60% had  PR, 58 and 40% CR. Organ responses occurred in 55 and 70% at 12 and 24 months. Eight patients relapsed/progressed. One patient with serologic progression had organ impairment at time of progression.
Based on this study, a small non-randomized trial has been recently conducted to evaluate the efficacy and safety of bortezomib in combination with ASCT in the induction, conditioning, and consolidation of patients with newly diagnosed AL amyloidosis 108 . The overall response (OR) rate after induction therapy of two cycles of BD was 57.1% and the CR rate was 28.5%. Eight (8/20, 40%) patients achieved hematologic CR after ASCT and 10 (10/20, 50%) after consolidation therapy. According to intention-to-treat (ITT) analysis, the CR rate was 47.6% ( 10 evaluable patients and 85.7% (18/21) according to ITT analysis. The hematologic response rate of CR and VGPR increased from 52.4% to 80% after ASCT treatment. The OR rate was similar after ASCT, and the CR rate increased from 40% to 50% after consolidation therapy.
Based the paucity of data, consolidation is not recommended as the standard treatment for patients with AL amyloidosis undergoing ASCT at our center.

# Deferred ASCT
Modern chemotherapy agents can induce hematologic and organ responses in AL, including those with cardiac involvement, but durability of response remains uncertain 109,110 . No study has demonstrated the prolonged progression-free survival (PFS) patients treated with non-transplant regimes akin to that achieved with ASCT.
It is now apparent that a proportion of patients with significant cardiac involvement will substantially improve after achieving a good response to chemotherapy. While studies have examined the role of bortezomib-based induction chemotherapy immediately prior to ASCT, no studies to date have specifically focused on the role of deferred ASCT in transplant-ineligible patients.
A recent study by Manwani et al. 111 reported on 22 AL patients who underwent deferred ASCT. All patients were transplant-ineligible at presentation, predominantly due to advanced cardiac involvement. All received bortezomib-based therapy, with 100% hematologic response (86% complete response (CR)/very good partial response (VGPR)), enabling reversal of ASCT exclusion criteria. Patients underwent deferred ASCT for hematologic progression (45%) or consolidation (55%). There was no transplant-related mortality. Hematologic responses post-ASCT: CR 50%, VGPR 27%, PR 18%, non-response 5%. In all, 85.7% achieved cardiac responses. Median overall survival (OS) was not reached, and median progression-free survival (PFS) was 54 months. This selected cohort achieved excellent hematologic responses, organ responses, PFS and OS with deferred ASCT.
If larger studies confirm these findings, this may widen the applicability of ASCT in AL Amyloidosis. immunosuppressive therapy given the propensity of this treatment to increase platelet requirements and induce platelet refractoriness. These patients should be considered for early HCT if an appropriate donor can be identified in a suitable timeframe. - A search for a MUD or a haploidentical donor should be initiated on patients without a matched sibling who show no response to immunosuppressive therapy after 3 months to allow a transplant to take place at 6 months.

# - Conditioning
- For matched sib HCT, fludarabine, cyclophosphamide and rabbit ATG. Additional GVHD prophylaxis will consist of methotrexate (day 1, 3, 6, 11), and cyclosporine for at least 6 months. o For matched unrelated donor and haploidentical HCT, rabbit ATG (day -9 to -7), fludarabine, low dose cyclophosphamide, and 2 Gy TBI (4 Gy if no previous immunosuppressive therapy). GVHD prophylaxis will consist of post-transplant cyclophosphamide (day 3 and 4), mycophenolate mofetil until day 35 and tacrolimus for at least 6 months. o See chapters on Conditioning and GVHD prophylaxis for details.
- Bone marrow will be the preferred source of stem cells in aplastic anemia. If considering an unrelated donor, choose one from a donor center that has a history of collecting consistently >2.5x10 8 NC/kg. - Patients with recurrence of SAA after stem HCT may be considered for repeat transplantation or immunosuppressive therapy.
Background  Severe aplastic anemia (SAA) is an uncommon condition with an annual incidence rate of approximately 2 per million. has been described in relation to medications (chloramphenicol, gold salts, anticonvulsants), infection (e.g. non-A, B, C hepatitis or HIV), immune diseases (thymoma, eosinophilic fasciitis, graft-versushost disease) and paroxysmal nocturnal hemoglobinuria (PNH). In children and young adults, hereditary conditions such as Fanconi anemia, dyskeratosis congenita and Schwachman-Diamond syndrome are important considerations and are frequently associated with non-hematological abnormalities. The manifestations of SAA occur as a result of damage to the hematopoietic stem cell compartment, making stem cell transplantation a natural treatment choice in this disease. For the purposes of these guidelines, SAA will be defined as follows:
- Bone marrow cellularity < 25% on an adequate biopsy and any two of the following:
- ANC (absolute neutrophil count) < 0.5 x 10 9 / L - Platelets < 20 x 10 9 /L - Reticulocyte index < 1.0
Results with Standard Treatment  Immunosuppressive treatment with the combination of antithymocyte globulin (ATG) and cyclosporine has become standard treatment in SAA. Recent trials outlined in the table below show response rates of 65 to 75% and survival rates of 75 to 80% using this approach. Responses are generally delayed, with 85% of responses occurring in the first 3 months after treatment. As a general rule, response rates at 3, 6 and 12 months are 67%, 71% and 78%, respectively. increased the rapidity of response and the number of complete and overall responses without increased toxicity, as reported by Peffault de Latour in 2022. The percentage of patients who had a complete response at 3 months increased to 22% from 10% and the percentage of overall response at 6 months increased to 68% from 41%. The median time to first response decreased to 3.0 months from 8.8 months. EFS increased to 46% from 34% but this is an early timepoint for this assessment as many events happen late.
Bone Marrow Transplantation in SAA  Matched sibling bone marrow transplantation is the treatment of choice for young patients with a suitable donor, as these patients enjoy excellent long-term survival with few relapses. Outcome of transplantation in this group of patients is limited by graft rejection (reported in 3 to 23% of recipients) and GVHD but overall survival is reported to be 63 to 93% in single institution reports. The CIBMTR reported results on 1699 recipients of allogeneic transplantation for this disease, with 5 year survival rates of 75%, 68% and 35% for patients aged 40, respectively.
Age at transplant has emerged as the major determinant of outcome and is used in most clinical algorithms to direct patients to the most appropriate treatment. Few quality of life studies have been carried out in this field; one such report found similar survival, event-free survival and quality-adjusted time without symptoms and toxicity (Q-TWiST) for bone marrow transplantation (BMT) and immunosuppression (IS), with BMT-treated patients enjoying longer periods free of symptoms and IStreated patients requiring closer medical care, transfusion support and medications. 24 The existing literature fails to distinguish outcomes for patients who undergo SCT as up-front treatment from those in whom it is used as second-line or salvage therapy. Small reports suggest that the outcome of SCT after failure of immunosuppressive therapy may approach that of first-line therapy, 6 while others have found a higher rate of graft rejection when transplant is undertaken in these circumstances. 25 The table below summarizes selected reports of outcome of BMT in SAA. more than two years after diagnosis have poor outcomes as shown below. It is essential that patients be taken to transplant as soon as possible (provided there are no contraindications) once patients are identified as being IST-refractory.

# Figure 1. Percent survival over time for patients with aplastic anemia
Experience has been developed in the area of haploidentical HCT for SAA. Previous experience with haploidentical donors for transplantation in other contexts has demonstrated a high rate of graft failure, infection and treatment-related mortality. In aplastic anemia experience is limited but the results appear promising. Two publications have described the outcome of SAA patients who have received non-myeloablative HCT followed by G-CSF (granulocyte colony stimulating factor) mobilized peripheral blood stem cell (PBSC) grafts. 31,32 GVHD prophylaxis was with post-transplant cyclophosphamide, tacrolimus, and mycophenolate mofetil. Informal meta-analysis of these two reports indicates that engraftment occurs in approximately 90% of cases, and that overall survival at 1-2 years is 70-80%. 33 Further improvement appears to have been achieved by including rabbit antithymocyte globulin into the conditioning. The Johns Hopkins (Baltimore) group reported on 20 patients with relapsed/refractory SAA, who received ATG, fludarabine, low dose cyclophosphamide, 200 cGy TBI, marrow graft, and posttransplant cyclophosphamide, MMF and tacrolimus for haploidentical translants 35 . Overall survival with a median follow-up of 32 months was 100%, and no graft failure or moderate to severe cGVHD occurred. They also report on 17 treatment naive patients treated with the same protocol with similar results, the exception being an increase in graft failure that was resolved by increasing the TBI to 400cGy. A BMT CTN study using this same protocol 36 in 31 patients for haploidentical transplants in relapsed/refractory patients produced a 1-year OS of 81%, with deaths due to disease and unsuccessful bone marrow transplant (mostly graft failure?). A similar protocol has been used in 42 published patients with hemoglobinopathies (no previous immunosuppression other than hydroxyurea). In this setting, it was found that a higher dose of TBI may be associated with a decreased incidence of graft failure (6/14 haploidentical HCT recipients developed GF after 200 cGy, 37 1/8 after 300 cGy, 38 and 1/17 after 400 cGy TBI 39 ). Given the encouraging results, we will offer haploidentical HCT to patients with relapsed/refractory SAA, using the Baltimore protocol with 200 cGy TBI. Despite we do not yet plan to routinely offer haploidentical HCT as primary treatment for SAA (without previous immunosuppressive therapy), if such a need arose, it would be prudent to use 400 instead of 200 cGy TBI.

# Transplant Details
In transplantation for malignant disease, the presence of graft-versus-host disease is associated with improved disease control and translates into superior disease-free survival. In aplastic anemia, graft-versus-host disease is deleterious to survival and has significant impact on patients' quality of life. Given the association between transplantation of stem cells from G-CSF mobilized peripheral blood and chronic GVHD (cGVHD), we will use bone marrow as the primary source of stem cells for transplantation in SAA. 30 Cyclosporine and short-course methotrexate will be used for GVHD prophylaxis given the results of randomized studies showing greater overall survival among patients treated in this way.
The conditioning regimen for patients undergoing stem cell transplantation for severe aplastic anemia has consisted of cyclophosphamide and ATG. With this approach it has been difficult to reduce the graft rejection rate below 10%, with consequent high transplant-related mortality (TRM) especially among older patients or those receiving transplants from mismatched or unrelated donors. The addition of fludarabine to Cy-ATG (FCA) has probably improved engraftment rates, and some series report engraftment rates of as much as 100% (see table below). 27 Retrospective comparisons of FCA with Cy-ATG show a trend to reduced rates of engraftment failure among those treated with FCA (0% vs. 11%, p=0.09). 28 We plan to use fludarabine 30 mg/m 2 daily x 4 days (days -5, -4, -3, -2), cyclophosphamide 60 mg/kg daily x 2 days (-3 and -2) and thymoglobulin 4.5 mg/kg (0.5 mg/kg day -2 followed by 2 mg/kg on day -1 and day 0) for patients receiving transplants from HLA-matched related donors
For matched unrelated donor and haploidentical transplants, we will use the Baltimore protocol. 34,39 Conditioning will consist of Thymoglobulin (0.5 mg/kg on day -9, 2 mg/kg on day -8, and 2 mg/kg on day -9), fludarabine (30 mg/m 2 /day on days -6 to -2), cyclophosphamide (14.5 mg/kg/day on days -6 and -5), and TBI 2 Gy on day -1 (4 Gy in a single fraction on day -1 if no previous immunosuppressive therapy). Marrow graft will be infused on day 0. Patients will receive cyclophosphamide 50 mg/kg/day on days +3 and +4, they will begin tacrolimus on day +5. Dosing will target trough level 10-15 mcg/L until 6 months and then taper it slowly to discontinue at 6 months.. They will also receive mycophenolate mofetil 15 mg/kg tid (max 1 g tid) from day +5 to day +35.
Evidence has repeatedly shown that cell dose is important in order to avoid graft failure in patients with SAA, including in the haploidentical setting using ATG, fludarabine, low dose cyclophosphamide, low dose TBI, and additional GVHD prophylaxis with PTCy, MMF, and tacrolimus 36 . If using an unrelated donor we will prioritize the use of donor centers with histories of collecting consistently >2.5x10e8 NC/kg.     

# Summary

# Sickle Cell Disease
- Referrals for allo-HCT for SCD (typically sickle cell anemia and sickle cell  0 thalassemia) will be accepted from the Northern and Southern Alberta Rare Blood Disorders programs.
- Requirements for allo-HCT include: o An HLA-matched sibling or a haploidentical relative without SCD (sickle cell trait is acceptable). o Demonstrated compliance with medications and follow-up. o KPS >70, GFR >30 mL/minute, LVEF >40% and DLCO >50% predicted. o No evidence of cirrhosis or active hepatitis. o RBC allo-antibodies directed towards donor RBC antigens (including major ABO incompatibility) can lead to prolonged transfusion requirement post-HCT but do not appear to be associated with graft failure. The decision to proceed with HCT in this setting should be individualized.
- Indications for allo-HCT include any one of the following: o SCD-related end-organ complication (previous cerebrovascular event, sickle nephropathy, hepatopathy, or pulmonary artery hypertension by right heart catheterization or echocardiogram (TRV >2.5 m/s). o Reversible SCD-related complication not ameliorated by hydroxyurea (>2 vasoocclusive crises/year requiring medical attention, >1 lifetime episode of acute chest syndrome, >1 episode of priapism/year requiring medical attention, proliferative retinopathy with visual impairment, >1 joint with avascular necrosis). o Red blood cell alloimmunization complicating chronic transfusion therapy. o Patients with combinations of clinical characteristics such as elevated WBC, elevated LDH, history of sepsis, age >35 and chronic transfusion who are at moderate-high risk of short-term mortality.
- Matched sibling donor HCT is performed according to the NIH protocol: o Conditioning is non-myeloablative and includes alemtuzumab (0.03 mg/kg D-7, 0.1 mg/kg D-6, 0.3 mg/kg D-5, -4, and -3) followed by TBI 3 Gy in a single fraction on D-2. o Grafts will be G-CSF mobilized PBSCs with a target of 10 x 10 6 CD34+ cells/kg recipient weight. o GVHD prophylaxis is in the form of sirolimus starting on D-1 with a trough serum level of 5-15 ng/mL. Sirolimus should be maintained for at least 1 year and should be tapered thereafter only when donor T-cell chimerism is >50% in the absence of GVHD. o In the setting of sirolimus toxicity, alternate immunosuppression with mycophenolate should be considered as posterior reversible encephalopathy syndrome has been reported with calcineurin inhibitor use in this setting. o Myeloid and T-cell chimerism should be measured at days 90, 180 and 365 post-HCT and yearly thereafter (however, if sirolimus is continued beyond 1 year, chimerism may be monitored more frequently, i.e. q. 3-6 months). RBC chimerism can also be monitored at these time points via Hb electrophoresis/HPLC.
- Haploidentical HCT is performed according to the Baltimore protocol: o Conditioning is non-myeloablative and includes Thymoglobulin (0.5 mg/kg on day -9, 2 mg/kg on day -8, 2 mg/kg on day -7), Fludarabine (30 mg/m 2 daily from day -6 to -2), Cyclophosphamide (14.5 mg/kg daily on day -6 and -5), and TBI (4 Gy in a single fraction on day -1). o Bone marrow graft. o GVHD prophylaxis consists of posttransplant cyclophosphamide (50 mg/kg daily on day +3 and +4), mycophenolate mofetil from day +5 to +35 (15 mg/kg/d tid, max 1 g tid), and sirolimus from day +5 to (target 5 to 15 ng/dL). Sirolimus should be maintained for at least 1 year and should be tapered thereafter only when donor T-cell chimerism is >50% in the absence of GVHD.
- Supportive care measures will be provided as outlined in the ABMTP standard practice guidelines, with the following modifications: o Patients should undergo exchange transfusion with a goal HbS <30% and Hb 90-100 g/L on D-10. Extended phenotype-matched RBC units (ABO, Rh D, C/c, E/e & Kell) should be used for exchange transfusion (the need for, on average, 7 units should be communicated to transfusion medicine in advance). o The transfusion target for Hb and platelets post-HCT should be 90-100 and 50, respectively. o If RBC allo-antibodies are identified it should be ensured that enough antigen negative units will be available for transfusion post-HCT (on average 6 units). o Hydroxyurea should be discontinued on 1 day before starting ATG or alemtuzumab. o G-CSF should be avoided altogether given the adverse outcomes associated with this medication in SCD. o Penicillin V prophylaxis should be provided until completion of pneumococcal vaccination, ie, 2 years posttransplant (in addition to trimethoprim-sulfamethoxazole until 3 mo after discontinuation of immunosuppression).

# Thalassemia
- At this time, allo-HCT for adults with thalassemia should not be offered outside of a clinical trial.

# Allo-HCT for Sickle Cell Disease
Background Sickle cell disease (SCD) is a severe monogenic autosomal recessive multisystem disease characterized by "sickled" erythrocytes. While SCD is an overarching term referring to all genotypes that cause this clinical syndrome, sickle cell anemia (SCA) refers to the most common form of the disease (70% of cases) resulting from homozygosity for the sickle cell allele (the majority of remaining cases result from hemoglobin SC and sickle cell/-thalassemia). 1 Sickled hemoglobin (Hb S) results from a point mutation in the -globin gene in which a single nucleotide of glutamic acid is replaced with valine. The consequence is a hydrophobic patch on the -globin molecule, which allows binding of -globin chains of two hemoglobin molecules when deoxygenated and thus polymerization of hemoglobin molecules. 1 Ultimately, the result is a distortion in the shape of the erythrocyte and a significant loss of its flexibility.
The underlying pathophysiology of SCD is complex. At the most basic level, sickled erythrocytes contribute to both chronic hemolysis and vaso-occlusion with resultant tissue hypoxia. Recent work has produced additional insights into SCD pathophysiology including the role of vasculopathy and endothelial cell dysfunction, dysregulated inflammatory responses and innate immunity, oxidant stress and iron dysregulation, and sensitization of the nervous system to pain stimuli. 2 The resultant clinical manifestations of SCD are summarized in table 1. hydroxyurea therapy; 3 have led to significant improvements in survival in children with SCD. 4 Hydroxyurea, the only approved disease-modifying pharmacotherapy for SCD, has been shown to reduce the incidence of vaso-occlusive pain crises, acute chest syndrome and red cell transfusion as well as improve survival in SCD. 3 Yet, over the last 30 years, there has been no improvement in the survival of adults with SCD. In a large American longitudinal study, mortality in adults with SCD appeared to increase by 1% in each year studied from 1979 to 2005 and the median age at death in 2005 was 42 and 38 years for females and males, respectively. 5 In another recent American prospective observational cohort, those with SCA had a median survival of 58 years. 6 In recent years, the most common cause of death in SCD is chronic cardiopulmonary disease, including chronic lung disease, pulmonary hypertension, congestive heart failure, myocardial ischemia and venous thromboembolic disease. 7,8 There is no convincing evidence to suggest that hydroxyurea alters the incidence or course of chronic SCD-related cardiopulmonary disease. 3,9 Thus, in adults, despite hydroxyurea and improvements in supportive care, SCD continues to reduce life expectancy.

# Allo-HCT for SCD
The recognition that those with SCD continue to suffer poor outcomes has led to growing interest in the development of disease-modifying and potentially curative therapy, including allogeneic hematopoietic cell transplantation (allo-HCT). In 1996, Walters et al demonstrated that allo-HCT from HLA-matched siblings with myeloablative conditioning (Bu/Cy/ATG) was feasible in children and resulted in sustained engraftment, elimination of vaso-occlusive episodes and stability in SCD-related end-organ damage present pre-transplant. 10 In children, experience with allo-HCT has rapidly expanded since that time; outcomes with a variety of conditioning strategies are excellent with CIBMTR (Center for International Blood and Marrow Transplant Research) and EBMT (European Group for Blood and Marrow Transplantation) registries reporting >90% 1 year survival and low rates of graft-versus-host-disease (GVHD) for those receiving HLA-matched sibling HCT. 11 In adults, there are fewer published reports of allo-HCT for SCD. However, encouraging early results with both myeloablative and non-myeloablative approaches have been reported (summarized in table 2). In the earliest attempt at myeloablative conditioning, the Chicago group reported on 2 patients receiving HLA-matched sibling peripheral blood stem cells (PBSC) after conditioning with Flu/Mel/ATG. Both patients engrafted and neither had SCD-related complications post-HCT, however, both died before 1 year from GVHD/infection. 12 A French group reported on 15 patients receiving HLA-matched sibling bone marrow after conditioning with Bu/Cy/ATG. All patients engrafted and one patient experienced early mortality due to cerebral hemorrhage in the setting of severe cerebral vasculopathy. At a median follow-up of 3.4 years: DFS was 93%, half of patients developed steroid-responsive grade 2-3 aGVHD, 2 patients developed moderate cGVHD, donor chimerism was sustained with all patients off immunosuppression, and all patients enjoy normal quality of life per the authors. 13 More recently, a multi-centre prospective American pilot study reported on 22 patients receiving HLA-matched sibling (17) or unrelated bone marrow (5 GVHD). One year OS and EFS were 91% and 86%. Four patients developed grades 2-3 acute GVHD, 3 developed moderate-severe chronic GVHD and one developed secondary graft failure and is alive after a second transplant. Significant improvements in health-related quality of life and pain were observed. 14 However, the most extensively reported experience in adults, and the approach to be used in the Alberta Bone Marrow Transplant Program (ABMTP), is with non-myeloablative conditioning from matched sibling donors. This approach aims to produce mixed chimerism to alleviate the SCD phenotype while maintaining low non-relapse mortality (NRM). The group at the NIH has reported results of a phase 1/2 trial involving 30 patients given alemtuzumab and low dose TBI conditioning followed by infusion of sibling HLA-matched PBSCs and sirolimus for GVHD/graft failure prophylaxis. 15 Patients were followed for a median of 3.4 years. All patients initially engrafted but 4 subsequently experienced graft failure with recurrence of SCD and one of these patients died from intracranial hemorrhage. In patients who had sustained engraftment, mean donor T-cell and myeloid chimerism were 48% and 86%, respectively. Chimerism was monitored frequently and withdrawal of sirolimus was considered at 1 year or more post-HCT if T-cell chimerism was >50% donor. Fifteen patients were able to discontinue immunosuppression at a median of 2.1 years and the remainder continue due to inadequate T-cell chimerism. NRM and GVHD were not observed. In those with sustained engraftment, specific SCD outcomes included reduction in tricuspid regurgitant velocity (TRV), no recurrent neurologic events, reduction in hospitalization rate and reduction in narcotic use. These findings have recently been replicated by the Chicago group in 13 patients. 16 At a median follow-up of 22 months; 1 patient experienced secondary graft failure (non-compliant with sirolimus) and the rest had stable mixed chimerism, 4 were able to discontinue sirolimus, quality of life scores improved at 1 year post-HCT and no TRM or GVHD were observed. There was significant improvement in cardiopulmonary parameters at 1 year. Of note, 2 patients were transplanted across major ABO incompatibility without engraftment concerns.

# Use of Alternative Donors
Most SCD patients will not have a suitable matched sibling donor available, thus, there is significant interest in the use of alternative donors. The use of unrelated donors remains investigational and should not be pursued outside of a clinical trial. The use of MUDs has predominantly been described in children with the largest series (29 patients) reporting a 28% treatment-related mortality after reduced-intensity conditioning with alemtuzumab, melphalan, and fludarabine, predominantly due to GVHD. 17 Haploidentical allo-HCT with post-transplant cyclophosphamide is promising. Initially, it was hampered by high rates of graft failure. 18,19 However, with the newest version of the Baltimore protocol (using pretransplant ATG and posttransplant cyclophosphamide), of 17 patients who underwent haploidentical HCT, all 17 survived, only one developed moderate-severe cGVHD, and only one developed graft failure. 37 Similar results were reported from Chicago. 36 We will use the Baltimore protocol, as outlined in the Summary, above. Novel approaches involving ex-vivo T-cell depletion, such as / T-cell depletion, have shown promise but are in their infancy. 20 The use of umbilical cord grafts has not been described in adult SCD patients. Patient Selection SCD results in phenotypic diversity. Recent efforts have focused on identifying specific clinical features that are associated with risk of mortality with standard SCD care. In a recent review of observational SCD studies: elevated TRV, leukocytosis and chronic transfusion were associated with 10% 2 year mortality, while elevated NT-proBNP, history of sepsis, elevated LDH (lactate dehydrogenase) and age >35 were associated with 5-9% 2 year mortality. Having a combination of two of these features led to 7-24% 2 year mortality. 21 Other end organ complications like sickle hepatopathy, sickle nephropathy, cerebrovascular events and acute chest syndrome are also associated with mortality. 22 In addition, recurrent vaso-occlusive crises, sickle retinopathy and osteonecrosis lead to significant morbidity. Given the low NRM, patients with over 5% 2 year mortality are likely to benefit from matched sibling HCT. In contrast, only patients with higher (>10%) estimated 2 year mortality are likely to benefit from higher risk grafts (MUD, haploidentical and umbilical cord). 21 Specific indications for allo-HCT in the SCD in the two non-myeloablative trials described above include: end-organ complication (previous cerebrovascular event, sickle nephropathy or hepatopathy, TRV >2.5 m/s), a reversible complication not ameliorated by hydroxyurea (>2 vaso-occlusive crises/year requiring medical attention, >1 lifetime episode of acute chest syndrome, >1 episode of priapism/year requiring medical attention, proliferative retinopathy with visual impairment or >1 joint with avascular necrosis) or red blood cell alloimmunization during chronic transfusion therapy. 15,18 RBC allo-antibodies directed towards donor RBC antigens (including major ABO incompatibility) can lead to prolonged transfusion requirement post-HCT but do not appear to be associated with graft failure. The decision to proceed with HCT in this setting should be individualized. Given the risk of secondary graft failure and infectious or toxic complications of allo-HCT, demonstrated compliance with medications and follow-up is crucial. Candidates for allo-HCT should be referred by an SCD expert after a comprehensive assessment of SCD status. Most patients who meet the above inclusion criteria will have an elevated HCT-CI (hematopoietic cell transplantation comorbidity index), making non-myeloablative conditioning an attractive option. Minimal functional status and organ function criteria, however, in the above trials has included: KPS >70, GFR >30 mL/minute, LVEF >40% and DLCO (diffuse capacity of lung for carbon monoxide) >50% predicted. Active hepatitis and a diagnosis of cirrhosis are exclusion criteria.

# SCD-Specific Supportive Care for Allo-HCT
Because of the unique physiological circumstances in SCD and the potentially toxic nature of allo-HCT, additional supportive care measures will apply to these patients in addition to standard allo-HCT care. 1. There is a risk of gonadal failure after low dose TBI. Patients should be counseled about fertility preservation options. Testicular shielding will be used during TBI treatment. Our center does not have the capacity to provide ovarian shielding. 2. Medication management: hydroxyurea should be discontinued the day before conditioning begins and G-CSF should be avoided given its association with severe SCD-related acute complications (vaso-occlusive events, acute chest syndrome, multi-organ failure and death). 23 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: May 18, 2021 Effective: May 18, 2021 3. Transfusion medicine: As per standard allo-HCT practice, transfused blood products should be irradiated. The target hemoglobin (Hb) in the peri-transplant period is 90-100 g/L. The need for extended phenotype-matched RBC units (ABO, Rh D, C, E & Kell) should be communicated to transfusion medicine. A median of 6 (range 0-15) units of RBCs transfused has been reported with the NIH non-myeloablative protocol. An RBC antibody screen should be performed during pre-HCT workup and if RBC allo-antibodies are identified, it should be ensured that enough antigen negative units will be available for transfusion post HCT. Given the physiologic stress (fever, infection, volume depletion etc.) likely to be encountered post-HCT and the associated risk of an SCD-related acute event, patients should undergo exchange transfusion with a goal HbS 50 and use of incentive spirometry when on the inpatient unit. 5. Infectious prophylaxis, including CMV monitoring and pre-emptive therapy, should be per current ABMTP practice guidelines, with the following modifications: a. Penicillin V prophylaxis should be provided until completion of pneumococcal vaccination, ie, 2 years posttransplant (in addition to trimethoprim-sulfamethoxazole until 3 mo after discontinuation of immunosuppression). b. While EBV viremia is expected to be uncommon, the approach should be individualized given the risk of secondary graft failure or GVHD with tapering immunosuppression, ie, use of rituximab only (without immunosuppression taper) should be considered.

# Allo-HCT for Thalassemia
There is very limited experience with allo-HCT for adults with -thalassemia major. Myeloablative approaches have resulted in high non-relapse mortality and outcomes are primarily determined by hepatic iron overload status. 24 There are no significant reports of reduced intensity or nonmyeloablative approaches in this patient population. At this time, allo-HCT for adults with thalassemia should not be routinely offered outside of a clinical trial. 

# Summary
- Eligibility for autologous hematopoietic stem cell transplantation (autoHCT) includes poorly controlled relapsing-remitting multiple sclerosis (RRMS) or apparent pseudo-progression in highly select group of patients - Relapsing-remitting patients will be eligible if they have failed a second disease modifying therapy (DMT), or are intolerant of multiple DMTs. In special cases, RRMS patients might be eligible having failed only one DMT (e.g, high risk of PML). - "Pseudo-progressive" patients will be eligible if they meet stringent criteria and consensus agreement by an MS neurologist experienced with the use of AHSCT in MS and a transplant physician - For transplant technique, we follow the Ottawa protocol, ie, mobilization with cyclophosphamide+GCSF, CD34 enrichment, conditioning with busulfan+cyclophosphamide+Thymoglobulin, and more intense infection prophylaxis than for patients with malignancies.

# Background
Multiple Sclerosis (MS) is the most common neurodegenerative disease of non-elderly adults in North America, with a prevalence of roughly 1/385 in Alberta, Canada 1,2 . It is characterized by central nervous system (CNS) demyelination and axonal loss/degeneration. Most patients present with the relapsing-remitting (RRMS) form of the disease, characterized by episodes of CNS dysfunction that typically last weeks with fair to good recovery 3 . The average patient is female, age 32, and while there is a small impact on life expectancy, it is typically in single digit years, thus patients will incur disability over decades and all the direct and indirect costs that entails 3 .

# First-Line Multiple Sclerosis Disease Modifying Treatment:
Since the mid 1990s, parenteral agents, interferon beta (Avonex, Rebif, Betaseron) and glatiramer acetate (Copaxone), to reduce relapse frequency in RRMS have been available  . While mildly to moderately effective, these agents reduce relapse rates by roughly 30%, and 30% or more of patients on these agents are considered treatment failures  . An additional subset of patients fails to tolerate these agents due to common adverse events of flu-like symptoms, leucopenia, transaminitis and a variety of skin manifestations  . In 2013, dimethyl fumarate (Tecfidera), an oral agent taken twice daily, was approved for RRMS, soon thereafter joining the approved first-line agents in Alberta. This agent has demonstrated roughly a 50% reduction relapse rate versus placebo and ~ 34% versus Copaxone .8,9 Tecfidera is associated with a small risk of lymphopenia, typically manifesting in the first 6-months of use, which typically persists, and if grade 3 or higher, requires discontinuation to avoid immunosuppressive complications. There have also been a small number of cases of PML, most of which have been linked to ongoing lymphopenia and ongoing use of Tecfidera. 10 Teriflunomide (Aubagio), a once daily oral agent approved in 2013, has also been added to the first-line arsenal. In the pivotal trials, Aubagio showed a 31-36% relative reduction in relapse activity, with adverse events that include hair thinning/loss and the risk of teratogenicity (based mostly on animal data). 11 A proportion of patients, approximately 4-14%, have what is considered to be aggressive multiple sclerosis, defined as reaching a high degree of disability within 5 years of disease onset or age 40, or transitioning to progressive MS within only 3 years of disease onset .12 Second Line-Escalation Disease Modifying Treatment:
In truth, escalation agents (typically classic immunosuppressants such as azathioprine and cyclophosphamide) have been used for decades, but those with randomized control trial evidence have only been available since 2000. Mitoxantrone (Novantrone) was approved for use in worsening RRMS and secondary progressive MS in 2000, although it's use has decreased considerably in the wake of relatively high rates of serious adverse events including cardiac dysfunction, leukemia and bone marrow damage. 13 In 2006, Natalizumab (Tysabri) was approved for use in RRMS in the context of marked failure on conventional agents. 14,15 Although highly effective, it has become evident that the risk of progressive multifocal leukoencephalopathy (PML) from JC virus entry into the CNS is as high as 1/30 patients based on risk factor stratification. 16,17 Ocrelizumab/ Ocrevus, approved in Canada in 2018 for both RRMS and PPMS, is a is a humanized anti-CD20 monoclonal antibody given by infusion every 6 months (similar to rituximab which is not approved as a DMT in Canada). In pivotal trials in RRMS, relapse rates were reduced by 46-47% vs Rebif, with a relatively tolerable adverse event profile. 18 There did appear to be a small increase in breast cancer cases in the Ocrelizumab group, but the numbers were small, and this is being evaluated in the post-marketing setting to determine if it is real or a statistical anomaly. This agent was approved by Alberta Blue Cross as a first-line agent in April 2019. In Alberta, all currently approved therapies not categorized as first-line therapy are considered second-line (i.e. there are no therapies solely categorized by Alberta and Blur Cross as third-line). These agents include:
Fingolimod/Gilenya: Gilenya was the first oral agent in RRMS was approved (for RRMS) in Canada. This agent has a novel mechanism of action characterized by activation of lymphocyte S1P1 via high-affinity receptor binding that subsequently induces S1P1 down-regulation, preventings lymphocyte egress from lymphoid tissues and thus reducing autoaggressive lymphocyte infiltration into the central nervous system (CNS). 19,20 In pivotal trials, there was a 54% relative reduction in relapses versus placebo (52% versus Avonex), as well as signigicant reductions in MRI lesion load, and markers of disability progression. 19,20  infectious (namely varicella zoster virus reactivation, i.e. shingles) and leads to an expected apparent lymphopenis due to its mechanism of action. 19,20 It, like all agents mentioned below is considered a second-line/escalation agent in Canada. 21 Since its approval, there have been upwards of 15 cases of PML associated with Gilenya use, with a cited risk of 3.12 per 100,000. 22 The only risk factor identified thus far is duration of use.
Alemtuzumab/Lemtrada: As well, Alemtuzumab, a very potent intravenous escalation agent with compelling results was approved in Canada in December 2013. 23 It is currently covered in the province of Alberta as a second-line treatment. Use of Alemtuzumab requires long-term monitoring of a minimum of four to five years of monthly blood and urine testing for potentially significant side effects (thyroid dysfunction, idiopathic thrombocytopenia purpura and Goodpasture syndrome). 23 More recently, additional risks including Acute acalculous cholecystitis and stroke during infusions have been reported. 24,25 Cladribine/Mavenclad: Cladribine, approved for use in RRMS in Canada in 2018, is a purine nucleoside analogue that selectively depletes peripheral lymphocytes without a major impact on cells of the innate immune system. It is given in oral form given as a weight-based dose in two relatively short courses over two annual cycles. Oral cladribine results in the peripheral depletion of lymphocytes that is gradual, occurring over several weeks, and is not associated with a cell lysis syndrome, has a greater impact on B cells than T cells, and is followed by gradual reconstitution of the peripheral lymphocyte counts over several months. 26 In pivotal trials, cladribine patients had a relative relapse reduction of 57% compared to placebo. Beyond typical mild adverse events, there is a risk of lymphopenia with cladribine, which may lead to a delay or cancellation of the second cycle of treatment if persistent. 27 The 2016, Atkins et al published the results of their landmark autoHCT trial using busulfan, revealing that no patient has had any evidence of inflammatory disease activity (relapse, gadolinium (gd) enhancing lesions) since transplant. 30 Unfortunately, no trial have not reliably shown a halting of or reversal of disability from neurodegeneration, hence conventional progressive patients are likely to incur all the toxicity and none of the benefit of such treatment. The role of mesenchymal stem cells in transplant is still under study.

# MS Treatment
First 

# Progression due to very active inflammatory disease (pseudoprogression):
- Rapid decline ( 5.0) with a cerebellar, brainstem, or pyramidal functional score of at least 3 points and impaired ambulation AND o MRI demonstrating two or more gadolinium enhancing lesions AND o Objective improvement in neurological exam with improvement in EDSS after trial of high dose steroids (as objectively determined by an MS neurologist)

# Exclusion criteria
- DMT failure in context of poor compliance/adherence (confirmation of dispensing by pharmacy is required) - >2 courses of cladribine is a relative contraindication (concern of poor stem cell mobilization) - Indwelling urinary catheter during the peri-transplant period (patients could make arrangements for intermittent catheterization during the high-risk period) - Pregnancy, inability or unwillingness to use appropriate contraception - Inability to provide informed consent for treatment - Previous malignancy with the exception of non-melanoma skin cancer or carcinoma in situ.
- Active infection or significant organ dysfunction.
- In patients at risk, CD4 T cell count <100/microliter (HIV infection per se is not an exclusion).
- History of congenital immune deficiency - Myelodysplasia/leukemia (marrow aspiration is required on all patients with CBC abnormality that could be due to myelodysplasia/leukemia and on all patients with history of myelotoxic drugs). - Absence of support/caregiver during 4 months peri-transplant - Inability to reside within the city of Calgary in the 30 days prior to and 100 days following transplant - Natalizumab or another anti-lymphocyte antibody should ideally be discontinued 2 months before stem cell mobilization chemotherapy.

# General note Re selection criteria
Patients most likely to benefit from autoHCT include those of relatively younger age, with relatively short disease duration, a relapsing form of MS (although cases of disease inactivity/stabilization after autoHCT in patients with progressive MS have been described, this appears rare and thus not proposed here), accumulating disability but still ambulatory, and ongoing disease activity despite DMT. 

# Autologous Hematopoietic Cell Transplant Details
Stem cell mobilization is achieved with cyclophosphamide, filgrastim and dexamethasone.
Cyclophosphamide, 2500 mg/m 2 IV over 1 h, is given in BMT clinic. Antiemetics and hydration are given per our standard practice; Mesna, 2500 mg/m 2 IV, should be given in two divided doses, the first one concurrently with cyclophosphamide and the second one 4 h later. Filgrastim is started on day 7 and continued until apheresis per our standard practice (see chapter "Donor Management, Including Mobilization"). Dexamethasone, 2 mg QID PO on the days of filgrastim administration, is used to enhance stem cell mobilization and to prevent filgrastim-induced flare of MS activity.

# Apheresis:
The target CD34 cell yield is 8x10 6 /kg (~5x10 6 /kg after CD34 cell enrichment). The minimum CD34 cell yield is 5x10 6 /kg (~3x10 6 /kg after CD34 cell enrichment). The target number of CD34 cells should be collected over one day to save apheresis/processing costs and ensure enrichment efficacy (see the chapter on Stem Cell Mobilization). Only if >2x10 6 CD34 cells/kg are available after CD34 cell enrichment, can the patient proceed into the autologous transplantation.
Graft processing: Both unmanipulated and CD34 cell-enriched grafts have been used. It is currently not known whether CD34 cell enrichment is necessary. We use CD34 cell enrichment as the Ottawa protocol, the results of which we wish to replicate, has used it. The mononuclear cells collected by apheresis are immunomagnetically enriched for CD34 cells. The CD34 rich fraction is cryopreserved and later used as the graft. The CD34 negative fraction is cryopreserved in one bag as backup for intractable viral infections.
Conditioning: Many different regimens have been used (Table 1). We use the Bu+Cy+ATG (Ottawa) conditioning (   Methyl-prednisolone X X X X X Stem cell infusion X GCSF ~0.5 ug/kg/d from d7 till ANC>1/nl X - Busulfan first dose is 2.4 mg/kg IV at a constant rate of 80 mg/hr (160 ml/hr for busulfan at 0.5 mg/ml concentration). Blood (4 ml green top (heparinized) tube) for busulfan PK is collected at the end of the infusion and at 1, 3 , 5 and 7 h after the end of the infusion. Subsequent doses are adjusted to target busulfan AUC >24 h interval between busulfan and cyclophosphamide infusions.
 Cyclophosphamide 50 mg/kg/day is given IV over 1 hour in 500 cc of normal saline. If actual weight is  ideal weight, cyclophosphamide is given as adjusted weight.
Adjusted weight = ideal weight + 0.25 x (actual weight minus ideal weight). Anti-emetics, as pre-medications for Cyclophosphamide, should be given per institutional policy and medical judgement. Hydration with Normal Saline, approximately 2 liters/m 2 /day, should be started on day -6, and at least 6 hours before cyclophosphamide and continued until 24 hours after the last cyclophosphamide dose.
* ATG (Thymoglobulin) 0.5 mg/kg is given IV on day -3 and 2.0 mg/kg IV on days -2 and -1 (no dose adjustment), over 4-6 hours each day. Pre-medicate with methylprednisolone 1.0 gram IV, acetaminophen 650 mg po and diphenhydramine 25 mg IV or PO 30 minutes before infusion. An in-line 0.22 um filter should be used for ATG administration.
 Methylprednisolone or prednisone is given to minimize the likelihood of fever (due to ATG, neutropenia or engraftment sydrome) and its negative effect on neurological status, according to the following schedule: Day -3 to -1, 1 g IV as premedication for ATG Day 0 to 3, 0. Infection prophylaxis posttransplant is more stringent than after autologous transplantation for hematologic malignancies. Anti-bacterial and fungal prophylaxis early posttransplant is given to avoid neutropenic fever, which could result in the worsening of neurological status. CMV and EBV monitoring and preemptive therapy is given because of severe lymphopenia produced by CD34 enrichment of the graft and by ATG. Specific measures:
- Valacyclovir 500 mg qd until VZV vaccination at 2 years posttransplant per our Standard Practice (see chapters "CMV/HSV/VZV/HHV6" and "Vaccination") - CMV and EBV PCR weekly from ~day 7 until 3 months posttransplant, and preemptive valganciclovir or rituximab per our Standard Practice (see chapters "CMV/HSV/VZV/HHV6" and "EBV/PTLD") - Levofloxacin 500 mg qd po or iv during neutropenia - Fluconazole 400 mg qd po or iv from day 0 until 1 month posttransplant - Pneumocystis/pneumococcal prophylaxis ideally with trimethoprim-sulfamethoxazole (  o Whether autoantibodies persist after autoHCT is controversial 7,8 - "GVHD" due to fetal T cells in skin of women with SSc post-pregnancy? 9 Incidence of SSc 
X X X X X X X X X X X X X X X X Physical Exam X X X X X X X X X X X X X X X X EDSS Exam- X X X X X X X X X X X CBC X X X X X X X X X X X X X X X X Chemistry panel X X X X X X X X X X X X X X X X PT/PTT X Pregnancy

# Prognosis without HCT
- Survival ~80% at 2 y, ~60% at 5 y, ~40% at 10 y per Altman et al 11 ; consistent with more recent studies 12,13 - Survival particularly low with o Diffuse scleroderma 14,15 o Heart, Lung, or Kidney involvement 11 o For diffuse scleroderma without or with only mild internal organ involvement, rapid Skin Thickness Progression Rate (STPR) 16  Onset of skin thickening defined as the first time the patient's fingers became swollen and never again returned to normal  STPR = mRSS / time interval between the onset of skin thickening and the documented mRSS in years  STPR >45 associated with survival of 76% at 2 y (comparted to ~86% with STPR 45 (p=.002)  Not validated for patients with >2 y interval between the onset of skin thickening and the documented mRSS Therapy Other than HCT
- Systemic immunosuppressive / antifibrotic / anticytokine agents -all studies retrospective or non-randomized prospective (thus dubious efficacy), except for cyclophosphamide, which was shown to have dubious efficacy in randomized studies, 17 and for MMF, which has efficacy similar to cyclophosphamide. 18 o Cyclophosphamide  In a randomized study of oral Cy vs placebo for 1 y, the Cy group had a smaller decline of FVC (1% vs 2.6% predicted, p<.03). 19 

# Autologous HCT
Multiple non-randomized and 3 randomized studies of autoHCT for SSc published (Table 1). From these studies it can be surmised that autoHCT is superior compared to pre-2015 conventional therapy (eg, oral or monthly IV cyclophosphamide) for the following indications: effusion). Efficacy appeared to be at least as good as with ASTIS/SCOT regimens as only 1 patient (4%) relapsed by one year, and trends toward improved mRSS and FVC were observed. We adopted this protocol in 2022 as an alternative for patients for whom the HCT would be relatively contraindicated by conventional criteria.
In Calgary, as of October 2022, we use primarily the modified ASTIS protocol:  2 dose dissolved in 500 mL D5W and infused over 2 h) with Mesna (500 mg/m 2 IV x 3, the first dose to be added into the Cy bag, the second and the third dose infused as IVPB at 4 and 8 h after starting Cy), hydration (500 mL NS over 1 h before each Cy infusion, and 500-1000 mL NS over 2-4 h after Cy infusion [500 mL over 2 h for 20 x 10e6/L. Target to collect 8 x 10e6/kg CD34 cells. Perform CD34 selection using CliniMACS. Target 5 x 10e6/kg CD34 cells for infusion. Cryopreserve.  2 dose dissolved in 500 mL D5W and infused over 2 h) with Mesna (500 mg/m 2 IV x 3, the first dose to be added into the Cy bag, the second and the third dose infused as IVPB at 4 and 8 h after starting Cy), hydration (500 mL NS over 1 h before each Cy infusion, and 500-1000 mL NS over 2-4 h after Cy infusion [500 mL over 2 h for 20 x 10e6/L. Target to collect 5 x 10e6/kg CD34 cells. No product manipulation (no CD34 cell selection). Cryopreserve. 

# Allogeneic HCT
- Case reports suggest efficacy.  - The only case series is a CIBMTR registry study of 12 cases with follow up of surviving patients of at least 1 year. 39 Of the 12 patients, 6 died, and 6 are alive at 13-60 months posttransplant. SSc status at last follow up was not given. Thus, this report is not informative Re efficacy, but suggests that mortality after alloHCT may be substantial. - AlloHCT should currently be considered only in patients with concurrent hematologic disease or under a clinical trial.
Pre-Transplant Tests/ Appointments (to be done within 3 months before stem cell mobilization)   

# Summary
- High-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) is indicated in second-or third line therapy (ie. as therapy for 1 st or 2 nd relapse) for patients with advanced germ cell tumor. Patients in first relapse who are likely to be cured with conventional dose chemotherapy (CDCT) alone such as TIP include those with gonadal or retroperitoneal primary site, who have achieved a CR or a marker-negative PR lasting >6 months prior to their first relapse. However, patients in first relapse who are unlikely to be cured with CDCT alone should be considered for HDCT/ASCT as part of initial salvage therapy. These patients include: o incomplete response to first-line cisplatin-based therapy o primary platinum refractory disease o relapse 6 months or less after achieving a marker-negative PR - For patients treated with CDCT in the initial salvage setting, HDCT remains an option in the third-line setting, should subsequent relapses occur.
- Patients do not benefit from HDCT/ASCT if they have: o a late relapse >2years after completing initial chemotherapy o relapsed/refractory primary mediastinal non-seminomatous GCT o very high risk disease ( 5 points) according to the International Prognostic Factor Study Group Score. - There is no role for HDCT in the first-line treatment of patients with germ cell tumor.
- Stem cell mobilization is planned with the second cycle of salvage chemotherapy, usually using TIP (paclitaxel 175 mg/m2 d1, ifosfamide 1.67g/m2 d1-3, cisplatin 33 mg/m2 d1-3), G-CSF 5-10mcg/kg/d starting day 9, and apheresis scheduled days 14-16. - Standard HDCT for GCT involves tandem transplants using 2 cycles of high-dose Carboplatin 700 mg/m2/d plus Etoposide 750 mg/m2/d, both given d-5,-4,-3 before ASCT. A minimum of 2 million CD34+ cells/kg is required for each cycle of HDCT. The second cycle of HDCT is given after recovery of granulocyte and platelet counts, unless there was a grade 4 nonhematologic toxic effect or no response to the first course. In general, the time between day 0 ASCT#1 and day 0 ASCT#2 is only 4-5 weeks.

# Background
Germ cell tumors (GCTs) account for less than 1% of all cancers; however, they represent the most common malignancy in young men between the ages of 15  etoposide and bleomycin (BEP). Patients who do not achieve long-term remission with initial chemotherapy are still curable with second-and even third-line treatment strategies. Options include cisplatin and ifosfamide with either paclitaxel (TIP) or vinblastine (VIP) with durable complete response (CR) rates of up to 63% in the Phase II setting in well-selected patients. Another salvage approach is the use of high-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT).

# Stem Cell Transplantation in GCT
In 2007, Indiana University published a large retrospective evaluation of their experience using high dose carboplatin and etoposide in 184 consecutive patients. Most patients (73%) were treated in the initial salvage setting. The high-dose regimen consisted of two cycles of 700 mg/m2 of carboplatin plus 750 mg/m2 of etoposide, both given intravenously 5, 4, and 3 days before ASCT. Patients with primary mediastinal nonseminomatous GCTs (NSGCTs) and late relapses were not included due to previously observed poor outcomes with HDCT in these subgroups. Four year PFS was 63% for the study cohort. Of the 184 patients, 116 had complete remission of disease without relapse during a median follow-up of 48 months (range, 14 to 118). Of the 135 patients who received the treatment as second-line therapy, 94 were disease-free during follow-up; 22 of 49 patients who received treatment as third-line or later therapy were disease-free. Of 40 patients with cancer that was refractory to standard-dose platinum, 18 were disease-free. A total of 98 of 144 patients who had platinumsensitive disease were disease-free, and 26 of 35 patients with seminoma and 90 of 149 patients with non-seminomatous germ-cell tumors were disease-free. Among the 184 patients, there were three drug-related deaths during therapy. Acute leukemia developed in three additional patients after therapy.  

# HDCT vs CDCT for relapsed GCT
The IT-94 randomized Phase III trial compared HDCT to conventional dose chemotherapy (CDCT) in the salvage setting. This multicenter international study was conducted in Europe between 1994 and 2001, and enrolled 280 patients from 43 institutions in 11 countries. The trial compared the efficacy of four cycles of CDCT using etoposide/ifosfamide/cisplatin (VIP)/VeIP versus three cycles of the same CDCT followed by one cycle of HDCT using carboplatin (200-550 mg/m2), etoposide (1800 mg/m2) and cyclophosphamide (200 mg/kg) followed by autologous stem cell rescue. Although no survival benefit was observed for HDCT:
- The majority of patients were treated during the initial salvage setting, unlike most HDCT Phase II trials; - Patients refractory to first-line platinum-containing chemotherapy were excluded;
- Only one cycle of HDCT was provided, using relative lower doses of carboplatin, while those studies which reported an advantage of HDCT over historical results with CDCT included two or more HDCT cycles.
Data from a large multicenter, international retrospective analysis of initial salvage chemotherapy in approximately 1600 subjects were reported in 2010. Approximately equal numbers of patients were treated with CDCT and HDCT respectively. Overall, PFS and OS were found to be superior for patients treated with HDCT as compared with CDCT. On multivariate analysis, important prognostic factors were identified that allowed patient stratification into five well-defined prognostic categories. These data have since been used to develop a new prognostic model for initial salvage therapy (see 

# Common Recommendation:
Patients with gonadal or retroperitoneal primary site, who have achieved a CR or a marker-negative PR lasting >6 months prior to their first relapse, could receive CDCT, usually with TIP. Patients with incomplete response to first-line cisplatin-based therapy, primary platinum refractory disease, or who relapse 6 months or less after achieving a marker-negative PR, are usually considered for salvage HDCT. For patients treated with CDCT in the initial salvage setting, HDCT remains an option in the third-line setting, should subsequent relapses occur.

# 2-3 Sequential HDCT Cycles vs Single HDCT/ASCT for GCT
German investigators reported the results of a randomized trial that was designed to answer the question of whether multiple sequential HDCT cycles are superior to a single HDCT cycle . Between November 1999 and November 2004, 211 patients with relapsed or refractory GCT were randomly assigned to treatment with either one cycle of conventional-dose cisplatin 20mg/m2, etoposide 75 mg/m2, and ifosfamide 1.2 g/m2 for 5 days (VIP) plus three additional cycles of highdose carboplatin 1,500 mg/m2 and etoposide 1,500 mg/m2 (CE) given in three divided doses over 3 days followed by reinfusion of autologous peripheral blood progenitor cells (PBPCs) 2 days later. Cycles were to be repeated at intervals of 21 days. Treatment in arm B involved three identical conventional dose cycles of VIP plus one additional cycle of high-dose carboplatin 2,200 mg/m2, etoposide 1,800 mg/m2, and cyclophosphamide 6,400 mg/m2 (CEC) given in four divided doses over 4 days followed by reinfusion of autologous PBPCs 2 days later. Patients with a creatinine clearance between 70 mL/min and 100 mL/min were scheduled to receive HDCT at a reduced dose of carboplatin 1,200 mg/m2 and etoposide 1,200 mg/m2 in arm A, and carboplatin 1,600 mg/m2, etoposide 1,600 mg/m2, and cyclophosphamide 1,300 mg/m2 in arm B. Patients with brain metastases received whole brain irradiation at a dose of 40 Gy immediately after random assignment in addition to their planned treatments.
Overall, 108 and 103 patients were randomly assigned to arms A and B, respectively. The study was stopped prematurely because of excess treatment-related mortality in arm B (14%) compared with that in arm A (4%; P= .01). As of December 2010, nine (5%) of 211 patients were lost to follow-up; 94 (45%) of 211 are alive and 88 (94%) of 94 patients are progression free. These investigators found no statistically significant differences in event-free survival (EFS), Progression-free survival (PFS) or OS between the two groups. Five-year PFS is 47% (95% CI, 37% to 56%) in arm A and 45% (95% CI, 35% to 55%) in arm B (HR, 1.16; P= .454). Five-year OS is 49% (95% CI, 40% to 59%) in arm A and 39% (95% CI, 30% to 49%) in arm B (HR, 1.42; P= .057). Toxicity was more severe within the single high-dose CECy arm with 16% treatment-related deaths as compared with 4% in the sequential highdose CE arm, which led to the premature closure of the trial and a nonsignificant trend toward improvement in OS for the sequential arm (80 vs 61%). The final conclusion of the study is that 2-3 www.ahs.ca/guru BMT Standard Practice Manual    

# Prognostic Models
Recently, Lorch and colleagues presented the results of a large retrospective international multicenter analysis conducted by the International Prognostic Factor Study Group to identify prognostic groups for initial salvage therapy independent of regimen intensity. Patients with salvage treatment administered as consolidation of first-line therapy without progression were excluded. This is the largest series ever reported and included approximately 2000 patients from 38 centers throughout 14 countries in Europe and North America. Seven factors were found to be significant for PFS on multivariate analysis including histology (seminoma vs nonseminoma); primary tumor site (mediastinal vs retroperitoneal vs gonadal); response to first-line chemotherapy (CR vs PR vs other); progression-free interval following first-line chemotherapy, -fetoprotein (AFP) level at salvage, HCG level at salvage and the presence of nonpulmonary visceral metastases. Each factor was assigned a point value and a sum score calculated for each patient. Scores were divided into five groups (very low risk, low risk, intermediate risk, high risk and very high risk) with distinct PFS and OS rates. The large, international and multicenter population of patients included in this study and the ability of the model to predict outcomes to both HDCT and CDCT initial salvage approaches will allow this model to be more widely applicable than the prior prognostic systems. Indeed, this is now widely considered the new standard predictive model in the relapsed/refractory setting.  
Calgary Results

# Introduction
High-dose chemotherapy +/-TBI is used in HCT to eliminate residual disease. In allogeneic HCT, pretransplant conditioning also induces an immunosuppressed state enabling engraftment.

# High-intensity/myeloablative conditioning (MAC)
with HCT has been shown to be superior to alternative treatments (e.g., consolidation chemotherapy for AML vs alloHCT, low-dose chemotherapy for lymphoma vs autoHCT). A multitude of MAC regimens have been studied and used. It is unlikely that, of commonly used MAC regimens, one is superior to others. It is prudent for centers to use regimens with which they have experience. In the 2010's and 2020's, regimens including fludarabine and an alkylator like busulfan have been increasingly used due to assumed lower toxicity and similar antileukemic activity compared to "conventional" MAC regiments like cyclophosphamide 120 mg/kg with TBI 12 Gy or cyclophosphamide 120 mg/kg with busulfan 12-16 mg/kg, 1 despite objective evidence for the assumption has been lacking.  In Alberta, fludarabine (250 mg/m2) + busulfan (~12.8 mg/kg, targeted to total busulfan AUC of 15000 uM.min) + TBI (4 Gy) has become the institutional standard for allogeneic HCT for hematologic malignancies in the 2000's/2010's. In combination with ATG-based GVHD prophylaxis, this regimen appears to result in better OS than CIBMTR average. 5 Reduced-intensity conditioning (RIC) with allogeneic HCT is an option for patients who are thought not to tolerate MAC due to comorbidities or advanced age. For younger patients without significant comorbidities, RIC is inferior to MAC due to the advantage of lower NRM being outweighed by the disadvantage of higher relapse leading to inferior OS, 6 though similar OS has been shown in some studies. 7,8 For the older patients or patients with comorbidities, it is clear that RIC is sufficient for durable stem cell engraftment and can lead to long-term relapse-free survival. However, whether RIC with alloHCT is superior to best available non-HCT treatment has not been documented in randomized studies. In Alberta, we prefer our MAC (Flu+Bu+TBI) to RIC, even in elderly patients, except for patients with significant hepatic or pulmonary comorbidities who are still thought to benefit from alloHCT. For the rare patients with significant comorbidities who are still thought to benefit from RIC-alloHCT, we will use fludarabine and treosulfan, because fludarabine + treosulfan (30 mg/m 2 ) was superior to fludarabine + busulfan (6.4 mg/kg) in a phase 3 study due to lower NRM and similar incidence of relapse. 9 In nonmalignant diseases like aplastic anemia, a lymphodepleting RIC (usually including cyclophosphamide, fludarabine, or low-dose TBI), is typically used. In addition, RIC is recommended for most patients with CLL (including Richter transformation) as of 2023 to reduce the risks of GVHD, toxicity, and NRM (see CLL chapter for more details).

# Drugs Used for Conditioning

# Busulfan
Busulfan is an alkylating agent believed to act through alkylation and cross-linking of DNA strands. Busulfan is cell-cycle non-specific and induces prolonged cytopenias when used alone or in combination with other agents. The liver converts busulfan to inactive metabolites, which are then excreted in the urine. Very little busulfan is excreted unchanged.
Busulfan is available as oral 2 mg tablets and as a 6 mg/mL solution for intravenous administration. When used in conditioning, the intravenous solution is preferred due to unpredictable absorption and metabolism of the oral form. When busulfan is administered for myeloablative conditioning within the ABMTP together with total body irradiation (TBI), an exposure (total AUC) of 15,000 uM.min is targeted due to the association of higher exposures with increased toxicity  . When busulfan is administered without TBI, an exposure of 18,000 uM.min is targeted 13 . Busulfan is administered at a constant rate of 80 mg/hour to facilitate PK modeling. The protocol for dosage adjustment is shown in Appendix B. If busulfan is used in a reduced intensity regimen, PK may be measured but dose adjustments are not made.
Common side effects of intravenous busulfan include nausea, vomiting, abdominal pain, anorexia, skin rash, hyperbilirubinemia (grade 3/4 in 30%), electrolyte disturbances, dizziness, headache and insomnia. Serious adverse reactions include hemorrhagic cystitis, male infertility, ovarian failure and venoocclusive disease of the liver. Seizures may also occur, and busulfan is always administered with anticonvulsant medications. The ABMTP uses lorazepam 1 mg po qid until 24 hours after the last dose of busulfan for seizure prophylaxis as other anticonvulsant medications show significant drug interactions.

# Treosulfan
Treosulfan is an alkylating agent that is structurally and pharmacodynamically similar to busulfan. However, treosulfan may be less toxic than busulfan despite similar antileukemic activity. This has been documented only in the RIC setting. In a randomized study of treosulfan+fludarabine vs busulfan+fludarabine in >50-y-old patients with comorbidities who had AML or MDS, treosulfan at 30 mg/m 2 resulted in a higher 2-y OS than busulfan at 6.4 mg/kg (71% vs 56%). 9 NRM was lower in the treosulfan arm, whereas relapse incidence was similar. In this study, busulfan was administered at 0.8 mg/kg i.v. every 6 hours x 8 doses. No PK-adjustment was done. Given the results of this study, we will adopt treosulfan for RIC. However, we will not adopt it for MAC, as it is unclear whether in combination with fludarabine and low-dose TBI, non-targeted treosulfan is superior to targeted busulfan given daily (not every 6 h as in the study). Also, the dose of treosulfan in the MAC setting is unknown. Of note, the above randomized study started with 42 mg/m 2 and was stopped due to "concerns about prolonged neutropenia and subsequent serious infectious complications in the treosulfan group". 9 On the other hand, the 42 mg/m 2 dose has been used with good results in some RIC regimens with fludarabine and 2Gy TBI. 14,15 Treosulfan is currently non-formulary, STEDT approval is needed.

# Fludarabine
Fludarabine phosphate (F-Ara-AMP) is a highly-immunosuppressive nucleoside analog with a profound impact on T-Lymphocytes. It is actively dephosphorylated to F-Ara-A in peripheral blood and rephosphorylated to F-Ara-ATP after intracellular transport. It inhibits DNA polymerase alpha, ribonucleotide reductase and DNA primase, thereby inhibiting DNA synthesis. It also interferes with RNA transcription and translation, and induces apoptosis.
Fludarabine is licensed for the treatment of chronic lymphocytic leukemia. Off-label indications include acute myelogenous leukemia, follicular lymphoma, certain T-cell lymphomas and membranous glomerulonephritis. Within the context of stem cell transplantation fludarabine is used for its immunosuppressive properties and is given in combination with high-dose busulfan or melphalan for myeloablation. Non-myeloablative regimens also feature fludarabine in combination with cyclophosphamide, TBI or lower-dose melphalan (70-90 mg/m2).
Side effects of fludarabine include nausea, vomiting, diarrhea and immune system dysfunction. The latter include incidents of autoimmune cytopenias, hemolysis, hemophagocytic syndrome and opportunistic infection (PJP, progressive multifocal leukoencephalopathy, cryptococcal infection). Herpes zoster, Cytomegalovirus and Epstein-Barr virus reactivations may occur. Overdosage may be associated with neurological effects, including blindness, coma, convulsions and death.
In the ABMTP the last dose of fludarabine is given at least 48 h prior to graft infusion, as the presence of residual fludarabine at the time of graft infusion is associated with a two-day difference in the time www.ahs.ca/guru BMT Standard Practice Manual Last Revised: Jan 31, 2023 Effective: Jan 31, 2023 to neutrophil engraftment 16 . Approximately 40% of fludarabine clearance is renal; dosage adjustments are recommended for patients with compromised renal function. Patients with normal renal function (creatinine clearance > 60 ml/minute) should receive full dose, while those with moderate renal impairment (creatinine clearance 45-60 ml/minute) should receive a 30% dose reduction. Patients with severely impaired renal function (creatinine clearance < 45 ml/minute) should receive a 70% dose reduction. This information is also contained in the BMT protocol data sheets maintained by pharmacy on Unit 57.

# Etoposide (VP-16)
Etoposide is a topoisomerase-II inhibitor which acts at the premitotic phase to inhibit DNA synthesis. It is cell-cycle specific with maximum activity in the S and G2 phases of cell division. Etoposide has been licensed by the US FDA for treatment of small cell lung and testicular cancers. A long list of offlabel uses includes acute myeloid and acute lymphoblastic leukemia and Hodgkin and non-Hodgkin lymphomas.
Etoposide is administered at concentrations no higher than 0.4 mg/mL as it may precipitate. It is given over 4 hours as hypotension may occur with more rapid infusions. Anaphylaxis should be treated with Solucortef 250 mg IV) +/-epinephrine 0.2-0.5 mg (0.2-0.5 mL of 1:1000 solution) subcutaneously or intramuscularly.
Common side effects of etoposide include nausea, vomiting, diarrhea and severe mucositis A rare but important side effect is anaphylaxis. Etoposide use in pretransplant conditioning is associated with severe cytopenias in 100% of treated patients.

# Melphalan
Melphalan is an alkylating agent that acts primarily through the alkylation and cross-linking of DNA. It is not cell cycle dependant. Melphalan is detoxified by chemical hydrolysis in plasma. The primary metabolites are inactive and dosage adjustment is not required in renal failure.
The FDA has licensed melphalan for palliative treatment of multiple myeloma and ovarian carcinoma. A black box warning indicates that severe myelosuppression may occur with melphalan. Its use has also been associated with development of chromosomal damage and leukemia, although this effect has been only rarely observed with the use of single-agent melphalan conditioning.
In addition to severe cytopenias, high-dose melphalan causes severe mucositis in transplant recipients. See guidelines on Head and Neck Complications (including mucositis) for guidelines on prevention and treatment of this complication.  

# Flu(250mg/m 2 ) + Bu(15000uM.min) + TBI(2Gy x2):
Fludarabine 50 mg/m2/day on days -6 to -2 Busulfan 3.2 mg/kg/day on days -5 to -2, adjusted based on pharmacokinetics in order to achieve total busulfan exposure of 15000 uM.min TBI 4 Gy delivered to midplane in two divided doses on day -1 or 0 (before graft infusion), at least 6 hours apart.

# Flu(250mg/m2) + Bu(18000uM.min):
Fludarabine 50 mg/m2/day on days -6 to -2 Busulfan 3.2 mg/kg/day on days -5 to -2, adjusted based on pharmacokinetics in order to achieve total busulfan exposure of 18000 molmin/L

# Cy(120mg/kg) + Bu(<24000uM.min):
Cyclophosphamide 60 mg/kg IV on days -8 and -7 Busulfan 3.2 mg/kg IV on days -5, -4, -3, -2. Avoid daily AUC >24,000 umol.min/L (avoid overall AUC >24,000 umol.min/L). The reason for using Cy+Bu instead of "conventional" Bu+Cy is a randomized study that showed borderline superiority of Cy+Bu due to lower hepatotoxicity and lower NRM. 17 This conditioning should be used only in case of fludarabine shortage. Bu+Cy has been found in two randomized studies to result in similar overall survival as Flu+Bu, 2,3 however, whether it is equivalent to Flu+Bu+4GyTBI is not known. Moreover, the busulfan toxic AUC of >24,000 uM.min has been determined in combination with fludarabine; it is not known whether it applies also to combination with cyclophosphamide. Moreover, in the randomized studies, daily busulfan dose was divided into two or four doses. We will use only one daily dose as an extrapolation from our Flu-Bu experience.

# Flu(120mg/m 2 ) + Mel(140mg/m 2 ) (RIC):
Fludarabine 30 mg/m2 days -5 to -2 Melphalan 140 mg/m2 day -1

# Flu(150mg/m2) + Treo(30g/m2) (RIC):
Fludarabine 30 mg/m2 on days -6 to -2 Treosulfan 10 mg/m2 on days -4 to -2

# Etoposide(60mg/kg) + TBI(5Gy x1):
Etoposide 60 mg/kg on day -4 TBI 500 cGy delivered to midplane in a single fraction on day 0 (before graft infusion) 

# Flu(250mg/m 2 ) + TBI(5Gy x1):
Fludarabine 50 mg/m2 on days -6 to -2 TBI 500 cGy to midplane on day -1 or 0 Flu(120mg/m 2 ) + Cy(120mg/kg): Fludarabine 30 mg/m2/day on days -6 to -3 Cyclophosphamide 60 mg/kg on days -4 and -3

# Flu(150mg/m 2 ) + Cy(29mg/kg) + TBI(2 or 4Gy x1) (Baltimore):
Fludarabine 30 mg/m2/day on days -6 to -2 Cyclophosphamide 14.5 mg/kg on days -6 and -5 TBI 2 or 4 Gy delivered to midplane in a single fraction on day -1 (2 Gy if previous immunosuppressive therapy, 4 Gy if no previous immunosuppressive therapy). Note: ATG is given as 0.5 mg/kg on day -9, 2 mg/kg on day -8, and 2 mg/kg on day -7

# TBI(3Gy x1) (NIH):
TBI 300 cGy delivered to midplane in a single fraction on day -2 Note: Alemtuzumab is given as 0.03 mg/kg on day -7, 0.1 mg/kg on day -6, and 0.3 mg/kg on days -5, -4, and -3..  

# Appendix B. Pharmacokinetic Adjustment of Busulfan
The routine use of pharmacokinetic (PK) monitoring for busulfan exposure has led to reduction in treatment-related mortality and is considered standard of care in this program. Drug exposure is estimated from the area under the plasma concentration-time curve (AUC), expressed in molmin. 1 The expected exposure is first determined from a test dose given prior to the start of the preparative regimen, and the first and second of 4 busulfan doses are adjusted accordingly. The exposure is also determined from the first dose (of the 4 doses), and the third and fourth doses are adjusted accordingly only if the estimated total AUC is >20% or <20% from the target total AUC. Dosage adjustments are made by comparing the AUC obtained from the test or first dose with the desired AUC according to the formula: Adjusted Dose (mg) = Actual Dose (mg) x ( Target AUC (uM.min) / Observed AUC (uM.min) )
Busulfan is infused at a constant dose of 80 mg/h. In the full intensity Flu+Bu preparative regimen pharmacokinetic testing is normally carried out on days -8 (test dose) and -5 (adjusted first full dose). The first dose (on day -5) and the second dose (on day -4) are adjusted based on the test dose PK. The third (day -3) and the fourth (day -2) doses are adjusted based on the first dose PK, but only if the estimated total AUC is >20% or <20% from target. Busulfan target AUC is 15000 M.min for patients receiving TBI as part of the preparative regimen. For patients not receiving TBI, the target is 18000 M.min. No PK determination / dose adjustment is done in the setting of reduced intensity conditioning. In case of Bu-Cy preparative regimen, the busulfan test dose is given on day -10, and busulfan treatment doses on days -8 to -5 are adjusted analogous to Flu-Bu, however, there is no target AUC. The goal is to not to exceed total AUC of 24000 uM.min. Appendix C. Results using our standard conditioning (Flu250 + Bu15000 + TBI4Gy) in combination with PBSC graft and ATG+CSA+MTX GVHD prophylaxis, using matched sib or 7-8/8 HLA matched unrelated donor Based on Ousia et al, 5 and additional unpublished analyses.Total patients AML patients Total patients AML patients    

# Background
Despite over 50 years of experience with allogeneic stem cell transplantation, aGVHD remains the main cause of death of patients in remission after this treatment, and cGVHD is associated with not only mortality, but mainly poor quality of life long-term. Risk factors may include HLA disparity, transplantation from an unrelated donor, female-to-male transplants, parity of female donor, recipient or donor age, peripheral blood stem cells (PBSC) vs marrow, or seropositivity for/reactivation of some herpes viruses. In Alberta, per analysis of HCT recipients from HLA matched sibling donors (MSD) or 7-8/8 HLA matched unrelated donors (URD) whose GVHD prophylaxis consisted of ATG, CSA, and MTX, the only risk factor for aGVHD was non-MSD and CMV D-R+ serostatus (donor negative, recipient positive), and the only possible risk factor for cGVHD was sex combination other than male donor with male recipient 1 .
The main target organs for aGVHD are the skin, the liver, and the gut. Clinical features range from localized erythematous skin rash to bullae and moist desquamation. Acute liver injury manifestation ranges from mildly abnormal liver enzymes (predominantly cholestatic) to severe hyperbilirubinemia. Gut injury manifestations range from nausea, vomiting, and diarrhea to severe abdominal pain and ileus. Chronic GVHD may involve virtually any organ, most frequently the skin, the gut, the liver, the eyes, the mouth, the lungs, and genitalia. Details on clinical manifestations are in Appendix 1. - The reason we prefer to combine CNI and antimetabolite with ATG in the MDS/URD setting is that with peripheral blood stem cell (PBSC) graft the addition of ATG results in lower incidences of aGVHD and cGVHD without negatively impacting relapse, which improves cGRFS (moderate-severe chronic GVHD-and relapse-free survival) and possibly also OS 3,4 . The reason we combine CNI and antimetabolite with PTCy in the haploidentical setting is that in the 1980's haploidentical HCT with CNI + antimetabolite had dismal outcomes and outcomes became acceptable only when PTCy was added, initially by the Johns Hopkins group and more recently by most centers in N.America and Europe. In China, ATG in combination with CNI + antimetabolite is frequently used for haploidentical HCT with good outcomes  . We might adopt it for haploidentical HCT in the future, if a randomized study shows superiority of the ATG-based vs the PTCy-based GVHD prophylaxis. - Re choice of CNI, there is no difference between CSA and tacrolimus in terms of OS. CSA may be associated with more grade 2-4 aGVHD but possibly less relapse and may be less nephrotoxic 9-12 . - Re choice of antimetabolite, there is no difference between MTX and MMF in terms of OS. MTX may be associated with less grade 2-4 or 3-4 aGVHD but greater toxicity (e.g., stomatitis)  . o Sirolimus + CNI + MTX or MMF  Has been evaluated only in the setting of nonmyeloablative HCT, where it was superior to CNI+MMF 17 . We do not use it as busulfan followed by sirolimus can result in a high incidence of liver venoocclusive disease/sinusoid obstruction syndrome 18 or microangiopathic hemolysis 19 . More studies are needed to determine whether this disadvantage is outweighed by the advantage of reducing aGVHD and cGVHD. o Naive T cell-depleted graft  Promising given low mortality due to infections and low incidence of cGVHD 21 , but more studies are needed to determine whether this advantage may be outweighed by increased incidence of relapse. o Alpha/beta T cell-depleted graft, with or without B cell depletion  Promising in pediatric HCT 22 , more studies are needed in adult HCT.
- PTCy + ATG + CNI  Promising in matched URD setting 23 , but more definitive studies are needed. 

# ATG + CSA + MTX details

# Methotrexate Administration and Adjustment Guidelines
The first dose of methotrexate is given on day +1, at least 24 hours following infusion of stem cell product. Dosage adjustments will be made for renal and hepatic function, and for patients with severe mucositis or known fluid collections (pleural effusions or ascites). Dosage reductions between categories are additive: The final dosage reduction is the sum of dosage reductions for renal or hepatic dysfunction, mucositis, and fluid collections (below). 

# Alternative if CNI, MTX, or MMF is not tolerated
Up until 2022, our guideline recommended to switch a patient not tolerating CSA to prednisone at the doses given below (next paragraph). A retrospective review of local data in 2022 showed that patients who prematurely discontinued CNI due to intolerance and were switched to corticosteroid prophylaxis had increased risks of grade II-IV and grade III-IV acute GVHD and GVHD-related NRM compared to those who received continuous CNI prophylaxis (Puckrin et al, submitted). Thus, in 2022 the guideline was changed to the following: CNI prophylaxis should be continued whenever possible -the medical team should tolerate mild/moderate renal dysfunction. A less favored option is to target lower cyclosporine trough levels. This option should ideally be avoided between day 15 and 28, as targeting 200-400 appears important between day 15 and 28 whereas lower target may be acceptable before day 15 or after day 28 24 . For those with severe toxicities which necessitate discontinuation of CNI, we now recommend combining MMF (1g BID until day +84) with corticosteroids according to the following schedule:
- Days 7-14 methylprednisolone 0. Patients planned to get CNI + MMF who cannot tolerate MMF may instead receive a corticosteroid until day 35 at 50% above doses in addition to continuing the CNI. Similar approach can be considered for patients for whom total MTX dose needs to be reduced to <50%.

# Therapeutic Monitoring and Dosing of CNI
Cyclosporine A (CSA) trough plasma level target for GVHD prophylaxis is 200-400 ug/L until day 56, then taper to zero by day 84, providing there is no evidence of GVHD. For non-malignant indications (e.g., aplastic anemia), CSA taper is initiated on day 180.
CSA Neoral  for oral use is available as a capsule (10mg, 25mg, 50mg, 100mg) and as an oral solution (100mg/ml). CSA Sandimmune  is for IV use. Initial dose is 2.5mg/kg IV q12h or 6.25mg/kg PO q12h if starting on day -1. This dosing typically results in levels higher than 400 ug/L, which requires subsequent dose reduction. If CSA is started later (eg, after day 84 for new onset grade 2-4 aGVHD or moderate-severe cGVHD), 2.0-2.5 mg/kg PO typically results within three days in the therapeutic level of 200-400 ug/L.
Conversion of IV to oral requires a 2.5 to 3-fold increase in dosage. The following algorithms can be utilized in guiding dose adjustment:
Inpatient, trough levels are drawn three times a week. If infused intravenously, CSA blood specimen should not be drawn from the same line used for administration. Outpatient, levels are drawn weekly, at a minimum. Consider repeating levels after 2-4 doses after a dose adjustment or the initiation/discontinuation of an interacting medication. For cGVHD, once maintenance dose is established for patients on long term CSA, frequency of trough level collection may be decreased to a monthly or as needed basis. In addition to monitoring drug levels, regular monitoring should also include blood pressure, CBC, serum electrolytes (Mg, K), renal function, hepatic function, and CMV and EBV PCR. Lower than the above recommended target levels may be used in case of renal or hepatic impairment, except for pure hyperbilirubinemia due to CSA.
CSA is a substrate and inhibitor of CYP3A4 and P-glycoprotein. Additional monitoring and dose adjustment may be required when starting or stopping drugs that inhibit or induce CYP3A4. Renal function should be closely monitored with co-administration of drugs that might exhibit additive/synergistic nephrotoxicity with CSA.
Patients are reminded to take CSA consistently with or without food to minimize variability. Capsules should be kept in the foil packaging until dose is ready to be taken. Patients are asked to leave capsules open to the air for no more than 15 minutes if needed to tolerate CSA's characteristic smell. Oral solution should be diluted in a glass container. Plastic and styrofoam containers should not be used. Orange juice and apple juice are recommended diluents by the manufacturer. Chocolate milk has also been used. Grapefruit and pomegranate juice should be avoided due to their interaction with the CYP450 system. The provided syringe can be wiped clean, but not washed as it may result in dose variation.
Tacrolimus trough plasma level target for GVHD prophylaxis/treatment is 5-15 ug/L. Routine taper (in the absence of GVHD) is the same as for CSA, i.e., from day 56 with the goal of reaching zero by day 84.
Tacrolimus (Prograf  ) is available for oral use as an immediate release capsule (0.5mg, 1mg or 5mg) and for IV use. A 1mg/ml oral suspension can also be compounded. HCT. This dosing typically results in levels higher than 15 ug/L, which requires subsequent dose reduction. If tacrolimus is started later (eg, after day 84 for new onset grade 2-4 aGVHD or moderatesevere cGVHD), 0.02 mg/kg IBW PO q12h typically results within three days in the therapeutic level of 5-15 ug/L.
Conversion of IV to oral requires a 2.5-4 fold increase in dosage.
The following algorithm can be utilized in guiding dose adjustment:
New dose = (current dose)(target whole blood level) (current whole blood level)
As for CSA, tacrolimus blood specimens should not be drawn from the same line used for tacrolimus administration. Levels are drawn three times a week inpatient and at least once weekly outpatient, less frequently after stable levels in case of cGVHD. Consider repeating levels after 2-4 doses after a dose adjustment or the initiation/discontinuation of an interacting medication. In addition to monitoring the levels, regular monitoring should also include blood pressure, blood glucose, CBC, serum electrolytes (Mg, K), renal and hepatic function, and CMV and EBV PCR. Lower than the above recommended target levels may be used in case of renal or hepatic impairment.
Tacrolimus is a substrate of CYP3A4 and p-glycoprotein. Additional monitoring and dose adjustment may be required when starting or stopping drugs that inhibit or induce CYP3A4. Renal function should be closely monitored with co-administration of drugs that might exhibit additive/synergistic nephrotoxicity with tacrolimus.
Patients are reminded to take tacrolimus consistently with or without food to minimize variability. Grapefruit and pomegranate should be avoided due to their interaction with the CYP450 system. 

# Grading of aGVHD
For aGVHD grading, we use the 1994 Consensus Conference grading system. 25 To determine the overall grade of aGVHD, organ stages need to be determined first: Grading ("Scoring") of cGVHD
For cGVHD scoring, we use the 2014 NIH scoring system 26 :
Organ Scores of cGVHD: 

# - Genital signs:
Female genitalia: 1) Mild (any of the following); erythema on vulvar mucosal surfaces, vulvar lichen-planus or vulvar lichensclerosus.
2) Moderate (any of the following); erosive inflammatory changes of the vulvar mucosa, fissures in vulvar folds.
3) Severe (any of the following); labial fusion, clitoral hood agglutination, fibrinous vaginal adhesions, circumferential fibrous vaginal banding, vaginal shortening, synechia, dense sclerotic changes, and complete vaginal stenosis. Male genitalia:
1) Mild: lichen planus-like feature;
2) Moderate: lichen sclerosus-like feature or moderate erythema; 3) Severe: phimosis or urethral/meatal scarring.

# Global Score of cGVHD:
Mild cGVHD:
- 2 organs involved with max organ score 1, plus lung score 0

# Moderate cGVHD:
- 3 organs involved with max score 1, or - 1 organ (not lung) with a score of 2, or - Lung score 1

# Severe cGVHD:
- 1 organ with a score of 3, or - Lung score 2 or 3
Frequency of cGVHD scoring: At initial diagnosis, at worsening, and at least every 3 months in the first year postHCT.

# Treatment of GVHD (initial)
For grade 1 aGVHD and mild cGVHD, we use a topical corticosteroid (e.g., betamethasone 0.1% cream bid). Observation-only is also reasonable. For a list of topical/ancillary therapies, see Appendix 2.
For grade 2-4 aGVHD and moderate-severe cGVHD, systemic corticosteroids remain the cornerstone of treatment. An exception may be sirolimus for aGVHD 27 , which should not be used in patients conditioned with busulfan 18,19 . Only 50% patients have a sustained complete or substantial partial response to a corticosteroid. Steroid-refractory or steroid-dependent patients usually have poor outcomes.
Dosing of systemic corticosteroids for initial therapy of grade 2-4 aGVHD and moderate-severe cGVHD has been derived from expert opinions. For aGVHD, we use 2.0-2.5 mg/kg/d prednisone (or equivalent), tapered over 2-3 months. For cGVHD, we use 1.0 mg/kg/d, tapered over 6-9 months. Attempts of lowering the initial dose of prednisone for grade 2-4 aGVHD have been associated with unexciting results. Per a randomized study of starting with 1 vs 2 mg/kg/d, the primary endpoint of lowering the cumulative prednisone dose by >33% was not reached as many patients who started with 1 mg/kg/d needed incrementation to 2 mg/kg/d 28 . However, this may not apply to grade 2a aGVHD.
Grade 2a aGVHD is defined as biopsy-confirmed UGI GVHD (nausea/vomiting/anorexia) with or without mild LGI GVHD (diarrhea <1 L/d), rash <50% BSA, and no hepatic involvement. It can be treated with 1 mg/kg/d prednisone + oral beclomethasone dipropionate 1 mg qid, with or without budesonide 3 mg bid (recommended if diarrhea) 29,30 . If no response in 10 days, increase prednisone to 2.0-2.5 mg/kg. If response in 10 days, taper prednisone over one week.
Adding an immunosuppressive drug to a steroid has been unsuccessful both for aGVHD and cGVHD  , except possibly for a CNI. The questionable benefit of adding a CNI to a steroid for first line treatment of cGVHD is based on expert opinions 36 and one randomized study of CSA+prednisone vs prednisone alone 37 which showed prednisone-sparing effect of the addition of CSA to prednisone, associated with a lower incidence of avascular necrosis, but no impact on cGVHD-related outcomes or OS. In a small study, tacrolimus had a 39% response rate in steroidrefractory patients 38 . In practice, many patients are already on CNI for prophylaxis. For the patients who are no longer on CNI, in Alberta we use the addition of CNI to prednisone optionally.
Next-Line Treatment of GVHD (Steroid-Refractory/Dependent)
Favorable outcomes following next-line (post-steroid) therapy have been infrequent with any therapy. Studies of next-line therapy suffer from small patient numbers, short-term follow up, lack of control arm, or cross-over design which makes the evaluation of impact on OS impossible. Thus, whether any additional treatment of steroid-refractory/dependent GVHD has a lasting benefit with acceptable toxicity has not been rigorously determined.
Only patients who failed systemic steroids should proceed to next-line therapy. Failure of systemic steroids has had multiple definitions. We use the EBMT-NIH-CIBMTR Task Force definition, 39 modified to a minor degree in REACH 2 and 3 trials 40,41 , i.e.,  For aGVHD, worsening after 3-5 days, no improvement after 5-7 days, incomplete response after >28 days, or inability to taper methylprednisolone to 0.5 mg/kg/d, or two failed attempts at prednisone taper necessitating prednisone dose increase to >0.25 mg/kg/d Ruxolitinib (Jak1/2 inhibitor) is our first-choice as it is the only post-steroid failure therapy clearly shown to be efficacious in randomized studies (REACH2 for aGVHD, REACH3 for cGVHD) 40,41 . However, the efficacy has been modest. Moreover, it is not known whether ruxolitinib improves OS, as both REACH1 and 2 had a cross-over design. In both studies, about one third of patients randomized to the control arm crossed over to ruxolitinib In REACH2, ruxolitinib, 10 mg bid orally, was superior to standard care (other IST) for steroidrefractory grade 2-4 aGVHD. In this trial, 309 patients 12 years old were randomly assigned (1:1) to ruxolitinib versus the investigator's choice of therapy (mostly ECP). At day 28, ruxolitinib achieved superior rates of overall response (PR+CR) (62% vs 39%) and CR (34% vs 19%). Superiority of ruxolitinib was maintained at day 56 (40% vs 22% overall response). Treatment was discontinued in 72% patients receiving ruxolitinib and in 85% of patients in the control group; most discontinuation was due to lack of efficacy. The most common grade 3 toxicity with ruxolitinib was thrombocytopenia, and anemia, and possibly infections, particularly CMV. Despite impact of ruxolitinib on OS could not be evaluated due to the cross-over design, it is notable that 18-month OS was only ~40% in both arms (Table S6 of the published study 40 ).
In REACH3, ruxolitinib, 10 mg bid orally, was superior to standard care (other IST) for steroidrefractory/dependent moderate-severe cGVHD. A total of 329 patients 12 years old were randomly assigned (1:1) to ruxolitinib versus the investigator's choice of therapy (mostly ECP). At 6 months, ruxolitinib achieved superior rates of overall response (50% vs 26%) and CR (7% vs 3%). Treatment was discontinued in 50% patients receiving ruxolitinib and in 74% of patients in the control group; most discontinuation was due to lack of efficacy. The most common grade 3 toxicity with ruxolitinib was thrombocytopenia, neutropenia, and anemia. Despite impact of ruxolitinib on OS could not be evaluated due to the cross-over design, it is notable that 12-month OS was 81% in the ruxolitinib arm and 84% in the control arm.
Dose reduction to 5 mg bid or 5 mg qd is required for cytopenias or renal or hepatic impairment.
For patients who have a response, ruxolitinib may be tapered gradually after 2 months (in aGVHD) or after 6 mo (in cGVHD). It is important that ruxolitinib is tapered gradually rather than discontinued abruptly or reduced rapidly, because a "withdrawal syndrome" that resembles systemic inflammatory response syndrome may be seen when ruxolitinib is discontinued in myelofibrosis.
Previous published experience (pre-REACH1/2) was limited to a retrospective study of 95 SR GvHD (acute or chronic) patients from 19 centres 42 . The dose in most patients was 5-10 mg bid, and the study showed an overall response rate of 81% with 46% complete remissions. Median time to response was 1.5 weeks. GVHD flared in only 7% of patients during steroid taper. The 6-month survival estimate was 79%, and the safety profile was favorable. Side effects included cytopenias and CMV reactivation. Our local experience with ruxolitinib for SR aGVHD in 2016-2020 includes 16 patients, with 5 CR, 6 PR/stable and 5 refractory (all GI). Local data for cGVHD has not been collected. Extracorporeal Photopheresis. For aGVHD, ECP has been evaluated only in retrospective studies. 43 In the largest one (n=128), 44 77% patients achieved PR or CR. A higher response rate was noted for grade 2 (compared to 3-4) aGVHD. The response rates appear to be the best for skin-only aGVHD. 43 In Alberta, we have not been able to reproduce the relatively high response rate in published studies.
For cGVHD, ECP has been evaluated in 3 prospective studies. In the largest one (n=83), 44% patients achieved PR or CR. In another prospective study, the response rate was only 31% for skin disease and variable for other organs. 45 In a randomized study of 100 patients that was focused on patients with skin cGVHD, cutaneous PR or CR at 3 months was achieved in 40% ECP patients vs 10% controls (p=.002) and extracutaneous PR or CR was noted in 30% ECP patients vs 7% controls (p=.04).
Toxicity is low, virtually only CVC-associated infections and thrombosis.
Because of the relatively low toxicity and because, apart from ruxolitinib, ECP is the only next line therapy with efficacy documented in a randomized, albeit small, study, ECP is a good choice treatment added to or used instead of ruxolitinib, except when precluded by logistics (eg, patient lives too far from Calgary). Recommended schedule is 3x a week, alternatively Monday through Friday (daily) every other week. If no clinical benefit within 3 months (for cGVHD, earlier for aGVHD), discontinue ECP. If clinical benefit, attempt to taper, unless tapering other drugs is a higher priority.

# Sirolimus.
For aGVHD, in a prospective phase 2 study in steroid-refractory (n=31) or intolerant (n=3) patients, PR+CR was achieved in 76% patients. 46 Similar response rate (86%) was described in a small retrospective study (n=22). 47 For cGVHD, 38 of 47 (81%) patients experienced PR or CR in a retrospective study. 48 Major side effects are hyperlipidemia, headache, poor wound healing, renal dysfunction, edema, cytopenias and hemolytic-uremic syndrome. Hemolytic-uremic syndrome is particularly problematic in patients treated concurrently with CNI. Sirolimus should not be used in the first 1-2 months after transplant if busulfan was used for conditioning and methotrexate was used for aGVHD prophylaxis, due to the high incidence of VOD/SOS and possibly also HUS. 18,19 Initial dosing is 1-2 mg/day. The initial dose of sirolimus must be significantly reduced in patients concomitantly treated with azole or macrolide antibiotics. Target therapeutic trough level is 5-15 ng/mL. The following algorithm can be utilized in guiding dose adjustment:
New dose = (current dose)(target whole blood level) (current whole blood level)
Sirolimus trough levels are initially drawn once weekly. Levels should be drawn 7 days after a dose adjustment or the initiation/discontinuation of an interacting medication. Once maintenance dose is established, frequency of trough level determination may decrease to a monthly or as needed basis.
In addition to monitoring drug levels, regular monitoring should also include blood pressure, lipid panel, CBC, and renal function.
Sirolimus is a substrate of CYP3A4 and p-glycoprotein. Additional monitoring and dose adjustment may be required when starting or stopping drugs that inhibit or induce CYP3A4. When starting an azole, sirolimus dose should be preemptively halved. Analogously, when stopping an azole, sirolimus dose should be preemptively doubled.
Patients are reminded to take sirolimus consistently with or without food to minimize variability. The oral solution should be diluted with 60 ml of water or orange juice in a glass or plastic cup. Grapefruit and pomegranate juice should be avoided due to their interaction with the CYP450 system.
An advantage of ECP and sirolimus for Albertan patients is that no special approval (eg, STEDT) is needed.
The agents listed below have shown some promise only for cGVHD (not aGVHD) and require a special approval (eg, STEDT).
Rituximab: Objective responses of cGVHD were initially reported in more than 70% of patients, mainly with cutaneous and musculoskeletal manifestations 43 . True response rate in steroiddependent/refractory patients is probably on the order of 50% (30% CR, 20% PR) 49 . Usual therapeutic scheme consist of 4 courses of rituximab at a dose of 375 mg/m 2 , but significantly lower doses may be equally effective 50 . Side effects include infusion reactions, mild hypogammaglobulinemia and late neutropenia.
Imatinib: Small prospective studies, using imatinib at a dose of 100-400 mg/day, indicate response rate at 6 months between 50% and 80% of patients with cutaneous, eye, lung, and gastrointestinal cGVHD 43,51 . Myelosuppression, fluid retention and dyspnea are the most common side effects. Ibrutinib: Ibrutinib, a BTK inhibitor, at 420 mg qd orally, was studied in 42 patients 52,53 . Five patients were not evaluable for response due to early discontinuation. Responses occurred in 29 (67%) of the 37 evaluable patients (9 CR, 19 PR), and were associated with meaningful steroid dose reduction. Sustained responses of >/=20, >/=32, and >/=44 weeks were seen in 20 (69%), 18 (62%), and 16 (55%) of the 29 responders, respectively. Death occurred in 9/42 (21%) patients, 2 due to relapse, 2 due to an infection, 3 due to GVHD, 2 unknown. Dose reductions were reported for 13 (31%) patients, mostly due to fatigue. Other side effects included nausea, diarrhea, muscle spasms, and bruising.

# Mycophenolate Mofetil (MMF):
In case series, the response rates to MMF is reported between 40% and 75% 43 . Side effects, including cytopenias, gastrointestinal discomfort and diarrhea, may require dose reduction or discontinuation. MMF can induce histopathologic changes of the GI tract mucosa which mimic intestinal GVHD 54 . A doubt on MMF efficacy has been shed by a randomized study of initial cGVHD with MMF+prednisone vs MMF alone, in which case MMF was not effective 35 .

# Infection Prophylaxis
Patients with chronic GVHD are immunosuppressed and their treatment with IST makes their immunosuppression even more severe. As these patients are at an increased risk of opportunistic infections, adequate surveillance and prophylaxis is necessary (see sections on infection prophylaxis).

# Prognosis of Chronic GVHD
The prognosis continues to be poor. In a FHCRC study of 250 patients with moderate-severe cGVHD with median follow up >5 years, at 5 years since cGVHD diagnosis about 1/3 patients were dead, 1/3 patients alive and on systemic immunosuppressive therapy (IST), and 2. FEV1 <75% predicted (even post salbutamol/albuterol), or 10% decline over less than 2 years (even post salbutamol)

# Absence of infection 4. Evidence of air trapping by CT or by PFT (RV >120% predicted). Small airway thickening or bronchiectasis by
CT is acceptable if no air trapping.

# Explanations of uncommon terms for mucocutaneous cGVHD
Lichen planus: A skin eruption characterized in its most typical form by pruritic polygonal purple papules. These small flat-topped papules may show a white lacy network on their surface, Wickham's striae. The oral changes are characteristically erythema with a reticulate lacy pattern on the buccal mucosa. Erosions may also be present. The entire oral cavity may be involved, as can the genitalia of men and women.
Poikiloderma: A dermatosis characterized by variegated cutaneous pigmentation, atrophy, and teleangiectasia. 
Morphea

# Summary

# CMV (cytomegalovirus) Disease Prevention
- Monitoring and preemptive therapy: Monitor plasma CMV by quantitative PCR weekly until day 100, then monthly until 1 year posttransplant. If >25,000 IU/mL plasma, treat preemptively with valganciclovir.
- Blood products: Use leukodepleted and irradiated blood products.
- Donor selection for HCT: Prefer a CMV serostatus-matched donor. This is of minor importance, except if ATG is used for GVHD prophylaxis in a seropositive patient undergoing alloHCT for a lymphoid malignancy -in this scenario choosing a seropositive donor is of major importance.

# VZV (Varicella Zoster Virus) and HSV (Herpes Simplex Virus) Disease Prevention
- Valacyclovir from start of conditioning until 1 day before VZV vaccination. o VZV vaccination should occur at 2 years posttransplant or later (later in patients on prolonged therapy with immunosuppressive drugs -wait until 3 mo after discontinuation of immunosuppressive therapy (systemic and topical) and no cGVHD activity). - In D+R+, 31% CMV reactivation needing preemptive Rx / 4% CMV disease 1 - In D-R+, 64% CMV reactivation needing preemptive Rx / 11% CMV disease 1 - Survival lower in D-R+ than D+R+ patients with lymphoid malignancies (Fig. 1), due at least in part to a higher grade 3-4 aGVHD incidence in D-R+ patients. 2 Lymphoid malignancies Myeloid malignancies Figure 1. Impact of CMV serostatus on overall survival in patients with lymphoid malignancies (A) and patients with myeloid malignancies (B). In multivariate analysis, the differences were significant in patients with lymphoid malignancies (p=.001) but not myeloid malignancies (p=.23).

# HHV6 (Human Herpes
- Autologous seropositive patient o 50% / 2%
- Syngeneic seropositive patient o 50% / 0% 

# Risk factors for CMV reactivation and disease:
- Seropositivity of recipient particularly if donor seronegative or cord blood - T cell depletion, particularly ex vivo - GVHD / immunosuppressive drugs

# Clinical manifestations of CMV disease:
- Frequent: Gastroenteritis, Pneumonia - Less frequent: Retinitis, Encephalitis, Hepatitis, Marrow suppression Prevention/ Prophylaxis of CMV Disease

# Transfusions and Hematopoietic Cell Donor Selection
- All blood products collected in Canada are leuko-depleted at the time of collection (CMV safe). Moreover, blood products for HCT recipients are irradiated prior to transfusion.
- CMV seronegative HCT donor is preferred for CMV seronegative recipient. 3 However, the difference in survival of seropositive patients receiving grafts from seropositive vs negative donors is minor, if any. 1,4 - CMV seropositive HCT donor is preferred for CMV seropositive recipient. 1,3,5,6 o Survival difference (between HCT from seropositive vs seronegative donors) in the setting of ATG-based GVHD prophylaxis is marked in patients with lymphoid malignancies (HR=3.1, p=0.001) whereas minor, if any, in patients with myeloid malignancies (HR=1.2, p=0.23) (Fig. 1). 2 o The survival difference is virtually zero in the setting of haploidentical HCT with posttransplant cyclophosphamide-based GVHD prophylaxis. 7 o In patients with lymphoid malignancies and ATG-based GVHD prophylaxis, if an HLA matched but CMV seronegative sibling donor is available and no HLA matched and CMV seropositive sibling donor is available, search for an HLA matched and CMV seropositive unrelated donor is recommended. 1
- Recipient CMV serostatus should ideally be determined before blood product transfusions, particularly platelet or plasma transfusions or IVIG. If CMV IgG is transferred from a CMV seropositive blood donor to a CMV seronegative recipient, the recipient may become falsely CMV seropositive. 8
Antiviral Drugs -Prophylaxis or Preemptive Therapy?
- Prophylaxis with val/ganciclovir, acyclovir, foscarnet, brincidofovir, or maribavir decreased the incidence of CMV disease modestly or not at all (if yes, then only during the period of taking the drug) and had no impact on OS due to poor risk:benefit ratio. - Prophylaxis with letermovir is safe but efficacy is limited (~halving of % patients with clinically significant CMV disease, i.e. CMV DNAemia requiring preemptive val/ganciclovir or CMV disease) 11,12 o Pros:  Potential reduction of incidence/duration of val/ganciclovir-induced toxicity like neutropenia (significant?)  Survival benefit?
- Shown only in a retrospective study, 13 not in a randomized study 12 - In Alberta (when using ATG-based GVHD prophylaxis), the only patients who might benefit are the D-R+ patients (as D+R+ and D+R-patient's survival is similar to the survival of D-R-patients) o Cons:
 Cost ($>20,000 for 3 months)
- Inpatients require STEDT approval - Outpatients are usually covered 70-80% by their insurance, but the 20-30% copayment may be too much  No impact on the incidence of CMV disease 12  CMV DNAemia monitoring with preemptive VGCV needed in addition to letermovir  Given only to high-risk patients (e.g., only seropositive patients or only D-R+), which may introduce a layer of complexity (letermovir + DNAemia monitoring in some pts, only DNAemia monitoring in other pts)  No activity against HSV and VZV, so val/acyclovir needed in addition to letermovir  CMV reactivation after end of prophylaxis 13,14 -extended weekly DNAemia monitoring may be needed (until 2-3 mo post letermovir discontinuation) - Prophylaxis with anti-CMV T cells o Efficacious and safe, but too costly o Cannot be used in D-R+ patients who would most benefit from the prophylaxis - Preemptive Therapy with val/ganciclovir o Never evaluated in a randomized study against no prophylaxis/no-preemptive Rx. Only one randomized study against prophylaxis.  In the randomized study of ganciclovir prophylaxis till d100 vs preemptive Rx, 15 CMV disease incidence was similar, toxicity was worse with preemptive Rx (fungal infections, neurotoxicity, no difference in neutropenia), OS was similar. o Nevertheless, preemptive Rx has become popular based on single-arm studies showing less CMV disease than expected with no prophylaxis, not more CMV disease than with prophylaxis, and improved safety compared to prophylaxis. 

# Preemptive strategy in Alberta:
- CMV DNA monitoring in plasma from day 0 to day 100 weekly, then monthly to one year posttransplant.
- Monitor all patients (including CMV seronegative patients with seronegative donors, as there is a small chance that the CMV IgG test result is falsely negative).
- If 5,000-25,000 IU/mL, repeat DNAemia in 3-7 days.
- If >25,000 IU/mL, start preemptive treatment with ganciclovir or valganciclovir (induction treatment, i.e., b.i.d.).
- In 1999-2007 we used a threshold of 10-20 pp65 antigen positive cells per slide (containing ~200,000 granulocytes) and found it to be satisfactory (~2.8% cumulative incidence of CMV disease and no CMV pneumonia in D+R+ patients (ATG-conditioned)). Between 2007 and 2012, we used a ProvLab in-house real time PCR assay and a threshold of 50,000 U/mL plasma, which corresponded to the previous pp65 antigenemia threshold. Since 2012, we have used commercial real time PCR assay (RealStar, Altona) and a threshold of 25,000 IU/mL plasma, which corresponded to the previous in-house real time PCR threshold.
- With this threshold, our incidence of CMV pneumonia has been <1%. 5 The incidence of CMV disease (mostly gastroenteritis) has been highest in D-R+ patients (11.2%), second highest in D+R+ patients (3.6%), and low in D+R-patients (0.8%) and D-R-patients (0%). 1
- Continue induction until a down-going trend of CMV PCR results, then switch to maintenance (q.d.). For example, if ganciclovir induction was started for 80,000 IU/mL, switch to maintenance after <80,000 IU/mL.
- Treat until <5,000 IU/mL at least twice, but treat for at least 3 weeks (e.g., at least one week of induction and at least 2 weeks of maintenance).
- Prolonged maintenance can be considered for patients at high risk of CMV disease (e.g., active GVHD, or recurrent CMV DNAemia requiring preemptive therapy).
- If preemptive treatment is given between 3 and 12 months post-transplant, check CMV DNAemia weekly. Resume monthly monitoring after DNAemia has been undetectable at least twice.
Ganciclovir/valganciclovir preemptive dosing, and management of toxicity.
- Induction with ganciclovir 5 mg/kg IV twice daily, or valganciclovir 900 mg p.o. twice daily, for 7 days.
- Longer induction is needed if after the 7-day induction CMV DNAemia has not dropped. In that case, continue induction until DNAemia has started to decline. - Maintenance with ganciclovir 5 mg/kg IV once daily or valganciclovir 900 mg p.o. once daily, for at least 2 weeks.
- Both ganciclovir and valganciclovir doses need to be adjusted in renal insufficiency.
- If ANC1.0/nL within 3 days, switch ganciclovir to foscarnet.

# Therapy of CMV Disease

# Diagnosis of CMV disease
- Diagnosis of CMV Enteritis requires histological or immunohistochemical evidence. PCR positivity alone is not sufficient for diagnosis. o Based on this data and the fact that pulmonary CMV shedding predisposes to CMV pneumonia, the diagnostic and therapeutic algorithm is as follows:  If CMV >10 3 IU/ml BAL, CMV pneumonia is possible/proven. Treat as CMV disease (below).  If CMV between 150 (detection limit) and 10 3 IU/ml BAL, CMV pneumonia is unlikely. Treat the CMV shedding with 1 week induction and 1-2 weeks maintenance.  If CMV undetectable, CMV pneumonia is ruled out.  If transbronchial lung biopsy was done at the time of the BAL and is positive for CMV pneumonia by histology or immunohistology, treat as proven CMV pneumonia.

# Therapy of CMV disease
- Induction with ganciclovir 5mg/kg IV twice daily, or Foscarnet 90 mg/kg IV twice daily, for 2-3 weeks. Followed by maintenance ganciclovir/valganciclovir/foscarnet for 3-4 weeks. - For CMV pneumonia, add IVIG 500 mg/kg every other day for 2 weeks. - ~70% adults infected - ~70% adult HCT recipients shed HSV post transplant (typically in the first month) and ~70% of the shedders developed HSV disease in pre-acyclovir era.
- <5% pts shed HSV and <<5% pts develop HSV disease post transplant since acyclovir prophylaxis VZV.
- >90% adults infected - 10-50% adult HCT recipients develop VZV disease (typically at 3-9 months post transplant) without acyclovir prophylaxis.
- Similar cumulative VZV disease incidence with acyclovir prophylaxis, however, the time of onset shifted to after acyclovir discontinuation.
Risk factors: Seropositivity of recipient, GVHD / immunosuppressive drugs (this may not be a risk factor for any VZV disease, but it probably is a risk factor for severe VZV disease 2 )
Clinical manifestations of HSV disease: Painful mucocutaneous lesions of oropharynx/genitalia, internal organs may be involved, (e.g., lungs, GI tract, liver, CNS).

# Clinical manifestations of VZV disease:
- Shingles (typically with reactivation)  neuralgia - Chickenpox (typically with primary infection)
- Internal organs may be involved, e.g. 

# VZV Prevention/Prophylaxis with Valacyclovir
- Use valacyclovir followed by VZV vaccination, as this strategy appears effective for eliminating post-herpetic neuralgia (Appendix A). 16 - Give valacyclovir until VZV vaccination, which should occur at 24 months posttransplant in patients free of active cGVHD and off of immunosuppressive therapy.
- For patients with longer duration of immunosuppressive therapy, continue valacyclovir until VZV vaccination, which should occur at 3 months after the discontinuation of immunosuppressive therapy (systemic and topical), when cGVHD is inactive.
- Valacyclovir should not be taken on the day of VZV vaccination or thereafter as it could minimize the immune response to the vaccine by killing the live vaccine. Take the last dose of valacyclovir on the day preceding the day of vaccination.
- Give valacyclovir to all adult patients. For pediatric patients or rare adults patients, who are HSV or VZV seronegative, refer to Table 1.
- Use valacyclovir 500 mg po once daily (preferred) or acyclovir 400 mg po twice daily (5mg/kg IV twice daily). For children <40 kg with oral intake, use acyclovir suspension 300 mg/m 2 po twice daily.
- If patient is on ganciclovir/valganciclovir/foscarnet/cidofovir, hold acyclovir/valacyclovir. - Instruct the patient to avoid skin contact with vaccinees who have developed a rash. Approximately 20% vaccinees develop a rash at 5-42 days post-vaccination.

# Post-exposure prophylaxis of VZV
- Important only for patients who are not on valacyclovir/acyclovir. Definition of exposure: residing in the same household, playmate (face-to-face), other face-to-face contact with an infectious person.
- If a seronegative patient has been exposed to a person with varicella or zoster, give varicella zoster immune globulin (or intravenous immunoglobulin) and/or treat with treatment dose of acyclovir/ valacyclovir for 3 weeks.
- If a seropositive patient has been exposed to a person with varicella or zoster, observe closely.

# Therapy of HSV and VZV Disease

# HSV Disease
- Valacyclovir 1000 mg twice daily or Acyclovir 400 mg po three times daily (5 mg/kg IV every 8 hours).
- Treat for 7 days or until resolution of lesions, whichever occurs later.

# VZV Disease
- Acyclovir 10-12 mg/kg every 8 hours for 1-3 days, then (if oral intake possible) switch to acyclovir 800 mg po 5x/d or valacyclovir 1000 mg po three times daily.
- Treat until 2 days after the last new lesion has crusted (generally 10-14 days).
- Hydrate patient to minimize acyclovir/valacyclovir nephrotoxicity.

# Resistance to Acyclovir/Valacyclovir
- HSV resistance is relatively common in immunocompromised persons (~5% Human Herpes Virus 6 (HHV6)
- >90% adults infected - ~40% adult HCT recipients have HHV6 detectable in blood, typically in the first 2 months - <10% adult HCT recipients develop HHV6 disease (encephalitis, ?rash, ?pneumonitis, ?bone marrow suppression/graft failure)
- Prevention: Insufficient data exist whether prophylaxis or preemptive therapy with ganciclovir or foscarnet is indicated. In Alberta, we use no prophylaxis or preemptive therapy.
- Therapy of HHV6 disease: Ganciclovir or foscarnet, same dose as for CMV disease. o Chemotherapy may be given while waiting for cellular therapy as a temporizing measure, if PTLD is aggressive.

# Background
Epstein -Barr virus  - EBV is a gamma-herpes virus infecting primarily pharyngeal epithelial cells and B cells.
- Over 90% of adults are infected (seropositive) 4 :
- EBV is detectable in blood by PCR at one time in 0-16% healthy donors.
- EBV is detectable in blood by PCR at one of multiple times in 14-83% monitored HCT recipients.
 In Alberta, with ATG-based GVHD prophylaxis, 82% HCT recipients reactivate EBV (have EBV detectable in blood by PCR) 5 .
-First reactivation on median day 33 (11 -318).
-Maximum EBV DNAemia: median ~50,000 IU/mL.
-Maximum EBV DNAemia reached on median day 55 (14 -398).
- Infected B cells are either quiescent (latent infection) or transformed to proliferate.
- Transformed B cells are eliminated by T cells in immunocompetent hosts.
- PTLD can develop in immunocompromised hosts.
- Reported incidence after HCT 0.2% -71%, in Alberta ~10% (using ATG).
- PTLD may be more frequent than clinically appreciated -of 31 retrospectively monitored patients with EBV DNAemia before death due to various causes, PTLD was detected on autopsy in 19/24 patients 6 . Therapy (given at diagnosis of PTLD in the absence of EBV monitoring) 2. Rituximab:

# Risk Factors for Developing EBV PTLD after HCT
- 50-100% efficacy (? -preponderance of single arm studies)  -see Table 1 - Toxicities/disadvantages of rituximab: 18 which may be clinically significant 19,20 o Vaccination onset needs to be moved to at least 6 months after the last rituximab dose
- Infusion reactions o Hypo-IgM/IgG o Neutropenia,

# Reduction of immunosuppressive drug(s) preemptively
- Efficacy and toxicity (GVHD?) in the setting of preemptive or prompt therapy not well studied - In the setting of Therapy, reduction of immunosuppression (RI) studied only in addition to rituximab 

# Alemtuzumab instead of ATG
- PTLD still occurs, though less than with ATG  - Alemtuzumab may be associated with more CMV disease and other non-EBV viral infections. 26 Moreover, impact of alemtuzumab on relapse has not been well studied whereas ATG with myeloablative conditioning has not been associated with increased relapse in 5 randomized studies. 27 In Alberta, since September 2015 we use preemptive therapy with rituximab plus taper of immunosuppression. We use the threshold of 300,000 IU/ml. This is a compromise between trying to minimize the number of deaths due to PTLD and to minimize the number of patients exposed to the risks of rituximab/taper of immunosuppression unnecessarily (Table 2 and 3). The addition of the taper of immunosuppression is an extrapolation from the study of Styczynski et al 21 showing overall www.ahs.ca/guru BMT Standard Practice Manual Last Revised: January 5, 2021 Effective: January 5, 2021 survival benefit in the setting of therapy (not preemptive therapy). The use of preemptive therapy in patients whose conditioning includes ATG is in line with EBMT guidelines. 28   

# Length of Interval between Rituximab Doses, and When to Stop Rituximab
- In the preemptive therapy setting and therapy setting, treatment has been reported once a week (375 mg/m 2 i.v.), until undetectable DNAemia, maximum 4 doses 14,17,21,29,30 . In Alberta, we adopt the weekly dosing given that o It is in line with EBMT guidelines 28 .
There is no evidence of benefit of more frequent dosing.
Weekly dosing saves rituximab, as most patients need only 2-3 doses to achieve undetectable DNAemia 14,30 .
One dose only may be sufficient (in preemptive setting) 15 .
- The only exception to the rule of weekly dosing is in a patient whose PTLD manifests with fever and the fever has not abated after 2-3 days following the first rituximab dose (and immunosuppression taper). In this instance twice weekly dosing is reasonable, so that failure of rituximab with immunosuppression taper can be pronounced early and second line therapy organized in 2 weeks after the first rituximab dose. Second Line Therapy 11,35 - To be used if no response to rituximab with immunosuppression taper in 2-4 weeks.
- If no GVHD and if donor is EBV seropositive, use DLI, starting with 10 5 T cells/kg.
- If active GVHD or if donor is EBV seronegative, use chemotherapy.
- Anti-EBV T cells can be manufactured in our Cellular Therapy Lab using IFNg-capture system. The main advantage over DLI or chemotherapy is no toxicity. However, this option should be discussed on a case-by-case basis as it is resource-intense and efficacy data are limited (12/16 responders using various donor sources). 13,36,37 Moreover, the efficacy is probably very low if patient is on immunosuppressive therapy for GVHD.
- Donor sources of anti-EBV T cells include:
- EBV specific T cells from the stem cell donor, manufactured from mononuclear cell apheresis product (10 9 WBCs) in 1-2 days. 13 To be used if the cell donor is EBVseropositive.
- EBV specific T cells from a 3 rd party haploidentical related, EBV-seropositive donor, manufactured from mononuclear cell apheresis product (10 9 WBCs) in 1-2 days.
www.ahs.ca/guru BMT Standard Practice Manual Last Revised: January 5, 2021 Effective: January 5, 2021 o EBV specific T cells from a partially HLA matched unrelated 3 rd party donor, off shelf. 38,39 This option is currently not available in Alberta due to logistics and high cost. Local manufacturing of EBV T cells is performed using Prodigy closed system, in which mononuclear cells are incubated overnight with EBV peptides in the presence of a cytokine capture reagent (a bispecific antibody for CD45 and IFNg) and then incubated with anti-IFNg conjugated to a magnetic bead. The magnetic (IFNg secreting, i.e., anti-EBV) T cells are then separated by a magnet.
Sustained remission of PTLD occurs in 70-100% cases after infusion of EBV T cells from the original stem cell donor, but in only 50-60% cases after infusion of EBV T cells from a 3 rd party, due in part to rejection of the 3 rd party cells.
- Chemotherapy may be given while waiting for cellular therapy as a temporizing measure, if PTLD is aggressive.
- Future options may include: 
- EBV

# Background
The literature on bacterial/Pneumocystis prophylaxis after HCT contains few randomized trials. Most of the randomized trials on bacterial prophylaxis are of limited value due to the emergence of bacterial resistance to the drug studied in the randomized trial after the follow-up period of the trial. Most of the trials on Pneumocystis prophylaxis were performed in HIV patients and recommendations were extrapolated to HCT patients. The literature has been well summarized in international guidelines. 1 These recommendations, including Calgary-specific deviations, are summarized below.
Recommendations for Peritransplant & Early Post-HCT (100) Period
- Pneumocystis jirovecii pneumonia (PJP) incidence in pre-prophylaxis era was 4% in the first 3 months, and 6% later after allogeneic HCT. 5 When PJP prophylaxis was used until approximately 6 months in allo HCT recipients not getting ATG (for GVHD prophylaxis), PJP incidence was 1%. However, with ATG, in Albertan patients using PJP prophylaxis until approximately 6 months, we have noted PJP incidence of 3%. 6 Specifically, in 278 patients without grade 2-4 aGVHD or moderate-severe cGVHD who discontinued PJP prophylaxis at 6 months or soon thereafter, no PJP occurred in the first 6 months, 8 PJPs occurred at 7-12 months, 2 PJPs occurred at 13-24 months, and no PJP at >24 months. As approximately 30% of patients with PJPs need to be treated in the ICU and approximately 15% were fatal, in 2018 we decided to extend PJP prophylaxis until 12 months, and to 24 months in patients with CD4 T cell counts < 200/microliter at 12 months. CD4 T cell count < 200/microliter is a well-recognized risk factor for PJP (reviewed by Messiaen PE et al, 7 consistent with Evernden C et al 6 ). Thus: - PJP prophylaxis in Alberta is routinely given to patients from engraftment until 12 months posttransplant. For patients with CD4 T cell count < 200/microliter at 12 months, prophylaxis is continued until 24 months. Patients treated with immunosuppressive drugs for chronic GVHD should continue PJP until 3 months after discontinuation of immunosuppressive therapy (systemic and topical), when cGVHD is inactive. o Sulfamethoxazole + trimethoprim (cotrimoxazole) is preferred to dapsone, atovaquone and inhaled pentamidine due to highest efficacy (see Tables) and broader antimicrobial spectrum (including S.pneumoniae, Toxoplasma, Nocardia). o Patients with documented allergy to cotrimoxazole may be desensitized (see Appendix).
Patients who experience non-allergic toxicity to cotrimoxazole (eg, cytopenia, increased ALT, increased creatinine), should be rechallenged with cotrimoxazole prior to being committed to long-term treatment with a second-line agent. o Multiple regimens of cotrimoxazole have been found near 100% efficacious for PJP prophylaxis (eg, 400/80 mg qd, 800/160 mg qd, 800/160 mg 3x a week) (see Tables). In Alberta, 400/80 mg qd is used due to simplicity. o For second-line prophylaxis, dapsone 50 mg qd is preferred. 6 Atovaquone as well as inhaled pentamidine have a high breakthrough PJP rate. 6,8 - Streptococcus pneumoniae disease incidence is significantly higher in allogeneic HCT recipients compared to general population (Figure 1). Peak incidence is at 3-24 months posttransplant. Risk factors include: o cGVHD (Fig. 1) o Splenectomy o Hypo-IgG, particularly IgG2 - Antibiotics covering S. pneumoniae are routinely given to all Albertan HCT recipients from engraftment until the end of PJP prophylaxis, as both cGVHD and low CD4 counts are risk factors for S. pneumoniae disease. In splenectomized patients, S. pneumoniae prophylaxis is continued indefinitely. - In autologous HCT recipients, both PJP and S. pneumoniae disease incidences are lower than after allogeneic HCT but higher than in the general population. For simplicity, we use the same PJP/ S.pneumoniae prophylaxis as for allogeneic HCT recipients. o Exception is for autologous HCT recipients who are cotrimoxazole-intolerant. In these patients it is acceptable to give only dapsone and omit penicillin. The rationale is that the incidence of pneumococcal infections after autoHCT is approximately 2-fold lower than after auto vs alloHCT (5 vs 12/1000 HCTs, 9 or 5 vs 9/1000 HCTs 10 ) so pneumococcal prophylaxis might be redundant. - In CAR T cell recipients, we use the same PJP and S. pneumoniae prophylaxis as for allogeneic HCT recipients. The reason is that per limited data available so far, reconstitution of CD4 T cell counts to >200/microliter appears to take 1 to 2 years, i.e., similar for ATGconditioned alloHCT recipients. 11,12 This approach is further supported by current guidelines of EBMT, ASCO, ASTCT, and CARTOX.  

# Comparison of prophylactic dosing schedules of Sulfamethoxazole + Trimethoprim and alternative anti-PJP drugs
Schneider MM et al: A controlled trial of aerosolized pentamidine or thrimethoprim-sulfamethoxazole as primary prophylaxis afainst Pneumocystis pneumonia in patient with HIV infection. 16  If no reaction occurs, patient can continue dosing at 1 single-strength tablet once daily. Allergic reaction can occur up to 30 days into this dosing, however, the reaction is usually mild so the doses do not have to be given in the clinic.

# Efficacy
If a mild allergic reaction occurs or if the desensitization process is interrupted for reasons other than allergic reaction, then give a test dose of half the last dose. If the patient tolerates this test dose, then restart dosing at the last dose.
If a severe allergic reaction occurs, administer epinephrine, 0.3-0.5 mL of 1:1000 dilution, subcutaneously every 10-20 min. If needed, follow by a corticosteroid (eg, 50 mg methylprednisolone IV q 6 h). If needed, follow by an antihistamine (eg, diphenhydramine 25-50 mg IV or IM or PO q 6 h) and normal saline IV. 

# Summary
- Primary prophylaxis with fluconazole 400 mg daily should be given to all allogeneic hematopoietic cell transplant recipients from days 1 to 28. Fluconazole prophylaxis is not routinely accompanied by galactomannan monitoring except in high risk patients. - Primary prophylaxis with Posaconazole 300 mg daily is given to patients with Grade 3-4 acute graft-versus-host disease (GVHD) for 90 days. - CAR-T cell therapy recipients should receive fluconazole prophylaxis during the neutropenic period (ANC 14 days, or prolonged corticosteroid use >3 days. - No primary prophylaxis or galactomannan screening should be applied to those who develop grade 1-2 acute GVHD, chronic GVHD (irrespective of severity), or to autologous transplant recipients.
- Secondary prophylaxis may be used. It requires consideration of the etiologic agent identified from the previous episode of invasive fungal disease, and of the previous response to antifungal therapy. - Empiric antifungal treatment is given to patients with persistent neutropenic fever not responsive to at least 4 days of appropriate antibacterial coverage. Micafungin or liposomal amphotericin B is used. The empiric antifungal treatment will be discontinued after 2 days of absolute neutrophil count (ANC)>0.5/nl for afebrile patients and after 4 days of ANC>0.5/nl for those who are persistently febrile.

# Background
Despite the recent development of novel and extended spectrum antifungal antibiotics, invasive fungal infections remain a significant cause of morbidity and mortality in stem cell transplant recipients. Mortality with these infections remains extremely high. These antifungal standard practice recommendations derive primarily from:
- European Conference on Infections in Leukemia (ECIL 7 guidelines 2018) 1 ;
- 2016 Aspergillosis 2 and candidemia 3 treatment guidelines of the Infectious Diseases Society of America; - Analysis of the important supporting literature; and - Local considerations (fungal epidemiology, drug availability, ongoing construction projects)

# Primary Prophylaxis
Primary antifungal prophylaxis is indicated for populations at high risk of developing invasive fungal disease, those being leukemic patients receiving chemotherapy, and allogeneic hematopoietic stem cell transplant (HSCT) recipients. Conceptually, prophylactic recommendations for the allogeneic HSCT population have been divided into the early neutropenic and the GVHD phases 1 .
The risk of invasive candidiasis is greatest in the early post-transplant period (phase I) due to the presence of neutropenia, severe mucositis, and central venous catheter use. In the post-engraftment period (phase II and III), few HSCT recipients require prophylaxis against Candida species, unless gastrointestinal GVHD or a central venous catheter (CVC) (the main risk factors) are present. Dissemination of endogenous Candida species colonizing the gastrointestinal (GI) tract is the usual cause of invasive candidiasis, although more rarely, it may be spread on the hands of healthcare workers. Autologous hematopoietic cell transplant (HCT) recipients have minimal risk for invasive candidiasis once neutropenia and mucositis resolve.
The risk of mold infection, while higher during the GVHD phase, is also relevant during the initial neutropenic phase. During phase I, prolonged neutropenia, active leukemia and prevalence >8% are the main risk factor for mold infection, being higher in bone marrow and umbilical cord blood transplants, and lower in nonmyeloablative and peripheral blood transplants. In phase II and III, cellmediated immunodeficiency caused by GVHD and its treatment is the main risk factor, especially in those receiving unrelated donor, mismatched or haploidentical transplants.
For these reasons, even though fluconazole is highly recommended in the initial neutropenic phase in low risk populations, it should be used when combined with a mold-directed diagnostic approach (i.e. galactomannan or CT-based) or a mold-directed therapeutic approach (i.e. empiric antifungal therapy) in high risk populations. Of note, a number of prospective and retrospective studies (as cited below) have evaluated various mold-active antifungals versus fluconazole as primary prophylaxis in the neutropenic phase and have failed to demonstrate differences in overall survival.
Primary antifungal prophylaxis in the neutropenic phase at our center is with fluconazole for 28 days due to a low incidence of invasive mold infection (<4% in past 3yrs). It should start from the end of the conditioning regimen. In high risk patients (UCB, active leukemia, prolonged neutropenia, prolonged steroid exposure), serum galactomannan monitoring twice a week during neutropenia will be added or voriconazole prophylaxis can be considered. If galactomannan screening is positive (defined by optical density 0.5 on two consecutive occasions) it will be followed by CT imaging +/bronchoscopy, followed by anti-aspergillus therapy if proven or probable aspergillosis. Maertens et al. have demonstrated that such a fluconazole plus galactomannan monitoring approach can be highly successful. 46 Allogeneic HSCT Recipients, Initial Neutropenic Phase Table 1. ECIL recommendations on primary antifungal prophylaxis in adult allogenic HSCT recipients: re-engraftment period - Fluconazole should only be used when combined with a mould diagnostic approach in centers that do not have HEPA-filtered rooms or have a high baseline incidence of mould infection 5-8%.
Antifungal

# Allogeneic HSCT Recipients, GVHD Phase
While fluconazole, itraconazole and voriconazole have been studied through the initial neutropenic phase and into the GVHD phase, posaconazole and fluconazole are the only anti-fungals that have been studied specifically in the setting of significant GVHD (grade 2-4 acute or extensive chronic). This was in a head to head prospective, randomized, placebo-controlled trial which revealed reduced proven/probable invasive aspergillosis and fewer deaths from invasive fungal infection in the posaconazole group. Overall survival and treatment-related adverse effects were similar. 36 In the setting of grades 3-4 acute GVHD (aGVHD), a prophylactic posaconazole strategy can be justified on a number of levels:
- Patients with aGVHD continue to have risk factors for invasive candidiasis, i.e. central venous catheter, potential GI aGVHD involvement, recently healed/healing conditioning-related mucositis. - The recent large (1800 patients) Italian prospective observational study demonstrated that grade 2-4 aGVHD remains an independent significant risk factor for invasive fungal infection (IFI) (hazard ratio of 6), predominantly invasive aspergillosis. - In the two most recent trials of mold-active anti-fungal (posaconazole and voriconazole) vs fluconazole (+galactomannan monitoring) essentially performed equally well. In the voriconazole trial, there was no difference in fungal-free survival or overall survival and a majority of invasive aspergillus infections in the fluconazole arm were picked up by galactomannan screening. While the posaconazole trial demonstrated a reduction in death from fungal infection in the posaconazole arm. - This will be a relatively small number (19) high risk patient population.
In the setting of chronic GVHD (cGVHD) requiring immunosuppression there are little data to guide prophylaxis:
- In the posaconazole trial, the rate of IFI in those with cGVHD was low in both arms and there was no significant benefit of posaconazole (5% in the posaconazole arm vs. 6% in the fluconazole arm). Details of the cGVHD were not provided. - The prospective Italian study revealed a striking difference in the incidence of IFI in those with de novo cGVHD (3.2%) versus those with cGVHD preceded by acute GVHD (19.4%) - There are no studies evaluating a galactomannan screening approach in patients with cGVHD and this approach is impractical to apply as these patients do not routinely have weekly lab work/follow-up. - Patients with cGVHD are likely not at high risk of invasive candida infections and therefore there is likely limited benefit to fluconazole prophylaxis.

# Autologous HSCT recipients
There is no evidence for primary prophylaxis improving outcomes after autologous transplantation. Therefore, we do not use it routinely. Based upon expert opinion only, prophylaxis may be considered for autologous HCT recipients who have, or are expected to have, the following conditions:
- Prolonged neutropenia and mucosal damage from intense conditioning regimens or graft manipulation - Receipt of fludarabine or 2-CDA (2-chlorodeoxyadeno-sine) within 6 months of HCT

# CAR T-cell therapy recipients
Invasive fungal infections are rare after CAR-T cell therapy and typically occur in patients with other risk factors such as prolonged neutropenia or additional immunosuppression 62 . There is little evidence to choose between an anti-yeast or anti-mold prophylactic strategy in this population 63 . Consensus guidelines from EBMT, ASTCT, CARTOX, and other groups recommend fluconazole prophylaxis during the severe neutropenic period (ANC <0.5). Anti-mold prophylaxis is recommended in the following patients:
Recent 

# Secondary Prophylaxis
Patients who received treatment for suspected or proven invasive fungal infection earlier in their disease course are at high risk of recurrent infection during subsequent treatment. The goal of secondary prophylaxis is to prevent relapse of prior invasive fungal disease, or the occurrence of another invasive fungal disease during a new high risk period (prolonged neutropenia, or a period of severe immunosuppression). No randomized clinical trials exist to guide choice of secondary prophylaxis, and no standard approach exists. Small retrospective studies have been published using liposomal amphotericin B, voriconazole, and caspofungin.  Benefit from secondary antifungal prophylaxis has been suggested by two large retrospective studies of allogeneic HSCT receiptients 40,41 , and a prospective study of voriconazole in this population 42 . No randomized clinical trials have been conducted.
The choice of antifungal agent should be based on: 1) the etiologic agent identified from the previous episode of invasive fungal disease; and 2) the previous response to antifungal agents (ECIL 7) 1 .
Where ongoing antifungal therapy is considered prudent, clinicians must be mindful of drug interactions, especially between azoles, calcineurin inhibitors and QT intervals.

# Empiric Antifungal Therapy during Febrile Neutropenia
Early studies demonstrated that treatment of neutropenic patients with persistent or recurrent fever (variously defined as fever after 4 -7 days of broad-spectrum antibacterial therapy) with amphotericin B reduced the incidence of documented invasive fungal infection and improved survival. 44 This has led to a strategy of empiric antifungal therapy for patients with persistent fever in neutropenia, and over time the agent of choice has moved away from amphotericin B deoxycholate to less toxic alternatives.
Several principles guide the choice of initial empiric antifungal therapy: - Liposomal amphotericin B (L ampho B) is as effective as amphotericin B deoxycholate (AMBd), with fewer breakthrough infections at completion of therapy. There are also fewer infusion-related adverse events (IRAEs) and less nephrotoxicity. 45 AMBd receives a D1 grading in the presence of risk factors for renal toxicity and should be avoided. 1 - Caspofungin is as effective as L ampho B in empiric treatment of suspected invasive fungal infections  - Voriconazole actually failed the 10% non-inferiority cut-off when compared with L ampho B for empiric therapy and did not receive FDA approval for this indication. It is included in the table below because it is superior to AMBd for the treatment of IA, 52 effective therapy for candidiasis, and efficacious for prevention of break through invasive fungal disease. 53 - Fluconazole has no activity against Aspergillus species or other molds, and is not approved by the FDA for this indication.
- Only amphotericin B preparations, posaconazole and isavuconazole would be expected to have activity against Mucorales species.
The caveat is that empiric antifungal therapy has never been directly compared with placebo or other antifungal strategies. Less desirable aspects of this strategy include over-treatment of patients without invasive fungal disease, with the associated side effects and costs. The strategy is also limited by the fact that fever is a non-specific marker of fungal infection and will miss invasive fungal disease not associated with fever (estimated to be approximately 7% from the preemptive strategy literature 46 ). For patients with prolonged antibiotic resistant fever in neutropenia (3-5 days of fever despite appropriate antibacterial coverage and no clinical or radiographic focus of infection) empiric antifungal therapy with L ampho B or Caspofungin/Micafungin will be added. Axial imaging studies (equivalent to HRCT of chest, and ultrasound/CT abdomen and pelvis) will be carried out for patients who remain febrile after 72-96 hours of empiric antifungal therapy. If these studies fail to demonstrate a clinical focus, treatment with G-CSF will also be instituted.
Empiric antifungal coverage should be discontinued in afebrile patients once ANC > 0.5 for two days.
In patients with persistent fever and no clinical or radiographic focus of infection, empiric treatment with antifungal antibiotics should be discontinued once ANC > 0.5 for four days. Alternative causes including CVC infection, drug fever and GVHD should also be considered. 

# Summary
Graft Failure due to Rejection - Early recognition of graft rejection is essential to avoid unnecessary delays in retransplantation. The diagnosis requires the following: o Severe pancytopenia (ANC < 0.5, reticulocytes < 1%, platelets < 20) for more than two weeks beyond day +14. o Bone marrow biopsy showing severely hypocellular bone marrow without evidence of recurrent malignancy. <5% donor T cells and myeloid cells, or clearly decreasing trend.
- Successful treatment requires close communication between treating physicians, workup and, where necessary, donor registries. - Continue supportive care until repeat transplant can be carried out. The choice of donor for a second transplant depends on availability of the initial or backup donor, outcome of the first marrow harvest or stem cell collection and timing of repeat collection.

# Poor Graft Function
- Poor graft function should be distinguished from rejection, as repeat conditioning is not a prerequisite for successful cellular therapy. The criteria for poor graft function are: o Two to three lineage cytopenias with transfusion requirement sustained for more than two weeks beyond day +14. o Bone marrow biopsy showing severely hypocellular bone marrow without evidence of recurrent malignancy. o Absence of severe GVHD. o Complete donor chimerism in T-cell and myeloid compartments.
- A CD34-enriched stem cell boost may improve peripheral blood counts in patients with poor graft function. - Although the optimal dose for stem cell boosts has not been determined, there does not seem to be an advantage to administering more than 3.25 x 10 6 CD34+ cells per kg. We request collection of 5-7 x 10 6 CD34+ cells per kg in a single apheresis session to ensure that after the CD34 cell enrichment, there will be at least 3 x 10 6 CD34+ cells per kg for infusion. - The use of cryopreserved HPC-A for preparation of CD34-selected boost products is associated with low yield and viability and we recommend the use of fresh products for this procedure. Background Engraftment Engraftment is a complex process involving homing of hematopoietic stem cells to the stem cell niche, interaction with bone marrow stroma and cytokines, differentiation into maturing and lineage-committed precursors and production of mature blood elements. In addition to the potency of the stem cell product, engraftment is affected by the following factors:
Use of growth factor support 2.
Graft source (marrow, peripheral blood or umbilical cord blood)
Graft composition (CD34 cell dose, CD34 subsets and CD8 cell dose 4.
Bone marrow microenvironment 5.
Preformed host antibodies against disparate HLA antigens 6.
Donor/host HLA mismatch Engraftment Failure
Failure of sustained allogeneic engraftment is an uncommon but serious complication of myeloablative stem cell transplantation. The term primary engraftment failure is used to describe a situation in which engraftment fails to occur, usually in relation to a preset timeframe. Secondary engraftment failure describes a situation in which engraftment has occurred but subsequently is lost. Clinically, persistence or recurrence of pancytopenia is noted without evidence of relapse of the underlying malignancy. The diagnosis of engraftment failure requires the following:
- Severe pancytopenia (ANC < 0.5, reticulocytes < 1%, platelets < 20) for at least 2 weeks after day +14. 2. Bone marrow biopsy showing severely hypocellular bone marrow without evidence of recurrent malignancy 3. Reemergence of host T-cells and loss of donor myeloid cells Most cases of engraftment failure are believed to be immune-mediated, although certain viruses (parvovirus B-19, human herpes virus-6 (HHV-6), cytomegalovirus and Epstein-Barr virus) and medications (ganciclovir, Septra) are also believed to contribute on occasion. Rates of graft failure vary with stem cell source, with engraftment failure (primary and secondary) occurring in 14% of transplants using unrelated bone marrow and 8-21% engraftment failure in adults receiving umbilical cord blood transplants. Mortality rates range between 40-50%, with infection as the primary cause of death in the majority of cases. Poor Graft Function Engraftment failure should be distinguished from poor graft function, in which a recipient with complete donor T-cell chimerism shows persistently low blood counts in the absence of severe GVHD and relapse. The mechanism underlying poor graft function is unclear but, like engraftment failure, it may be primary (peripheral blood counts do not recover after conditioning-related nadir) or secondary (occurring at some time after engraftment).
Criteria for the diagnosis of poor graft function includes the following:
- Two to three lineage cytopenias with transfusion requirement 2. Sustained for at least two weeks beyond day +14 3. Hypoplastic or aplastic bone marrow 4. Complete donor chimerism 5. Absence of severe GVHD and relapse

# Management of Graft Failure
Due to the high mortality of sustained pancytopenia and the inevitable delays in procuring new stem cell products for repeat transplantation, early diagnosis of engraftment failure is essential. This requires a high degree of suspicion in patients at higher than average risk of graft failure combined with early diagnostic testing in suspected cases. In the case of primary engraftment failure a bone marrow biopsy and peripheral blood chimerism (sorted to test T-cells and disease phenotype cells separately) should be carried out on day +28 in the case of transplant from adult donors and day +42 in the case of umbilical cord blood transplants. The same investigations should be carried out if unexplained pancytopenia persists for more than two weeks in a previously engrafted patient.
Early management of patients with engraftment failure includes supportive care with blood transfusions and treatment of infection. Definitive management requires repeat conditioning and stem cell infusion. The choice of donor for a repeat transplant in engraftment failure depends on the availability of the initial or backup donor, the outcome of the first marrow harvest or blood stem cell collection and the timing of repeat collection.  In general the administration of CD34-selected stem cell boosts appears to be safe and is associated with improved peripheral blood counts (Table 1). The only toxicity noted with infusion of these products appears to be graft-versus-host disease, which is clinically mild (grade I-II acute GVHD) in the majority of cases. The time to peak response appears to be 1-3 months, although responses have been reported as early as 10 days after the infusion. 5 Where it has been examined, the total dose of CD34+ cells administered in a stem cell boost has not been associated with response. 3,4,6 The overall response (the difference between the absolute neutrophil counts at 8 weeks and prior to the infusion) appears to plateau at a threshold CD34 cell dose of 3.25x10 6 CD34+ cells/kg. 3 It is recommended that G-CSF mobilized peripheral blood stem cells (HPC-A) be collected fresh for CD34 selection as the use of cryopreserved HPC-A has been associated with low yield and viability of CD34 cells after processing. 8 1 www.ahs.ca/guru BMT Standard Practice Manual 

# Summary
- Patients who relapse after stem cell transplant have poor prognosis. It is doubtful that repeat transplantation improves this. - Patients with acute leukemia relapsed after transplant should be considered for donor lymphocyte infusion, palliative chemotherapy, clinical trials or palliative care. It is possible that highly selected patients with relapsed acute leukemia may benefit from a repeat transplant. These patients will typically be: o Young (age  1 year after first transplant - Recent non-comparative trials have demonstrated that DLI following azacitidine is feasible and may result in disease control in relapsed AML or MDS. Toxicity appears to be minimal. For patients without a history of grade 3-4 acute or moderate to severe chronic GVHD, this is our preferred strategy for highly motivated patients and is described in detail in the body of these guidelines and in the referenced publications. It is recommended that screening for targetable mutations be repeated at relapse for all relapsed myeloid malignancies. Patients with mutant FLT3 may be eligible for treatment with gilteritinib.
- Young (age < 26), fit patients with relapsed B-acute lymphoblastic leukemia should be considered for CD19 CAR T-cell therapy. 1,2 - Options for patients with relapsed MPN (with < 5% blasts), CML or CLL include novel therapies (later-generation TKIs, B-cell receptor antagonists, BCL-2 inhibitors) if the patient has not previously been exposed to them. Other options include DLI or palliative/supportive care. Second allogeneic transplants will be rare in this population. represents optimal care. This review attempts to outline areas in which a second transplant should be considered for individual patients who relapse.

# Acute Leukemia
The natural history of acute leukemia that has relapsed following allogeneic bone marrow transplantation has been described in two reports. A report by Mortimer et al. described the outcome of 95 patients treated at a single center. 3 Fewer than half of these patients received intensive chemotherapy for the purpose of reinduction of remission, and this was successful in only 15/44 patients treated. Two patients who entered remission survived for longer than 18 months. A larger report by the EBMT describes the outcome of 117 patients with acute leukemia who relapsed following allogeneic transplant. Only 32/77 patients treated with chemotherapy entered a complete remission. Patients who entered remission experienced median survival of 1 year, while those who failed reinduction survived a median of only 4.5 months. Second transplants had a negligible impact on overall survival in this cohort, as 8/9 second transplant recipients died of complications. 4 Aside from conventional chemotherapy, as described above, non-transplant options for acute leukemia patients who relapse after allogeneic transplant include cellular therapy in the form of donor lymphocyte infusion (DLI). While AML is of intermediate sensitivity to DLI (reported response rates vary from 0 -60%), most patients treated in this way do not experience prolonged survival due to graft-versus-host disease, infection and relapse. Despite the sensitivity of ALL to graft-versusleukemia effects, responses to DLI in this disease are almost never seen and tend to be short-lived.
More recently, novel therapies have been identified with activity in relapsed/refractory acute leukemia. Clofarabine, a second-generation nucleoside analogue, has shown activity in this setting. The combination of clofarabine and high-dose cytarabine shows overall response rate of 47% vs. 23% (p<0.0001) for high-dose cytarabine alone. Included in this response rate are complete responses of 12% vs. 5% (p=0.0005). 5 While event-free survival appeared superior with the combination of clofarabine and cytarabine, overall survival was still poor and identical between the two arms of this phase III study. Azacytidine, a DNA demethylating agent with activity in MDS and AML can be safely given after stem cell transplant and survival may be prolonged in a subset of patients with "indolent" progression of AML when azacitidine is used in combination with DLI. The multikinase inhibitor sorafenib or FLT3 inhibitors such as gilteritinib show activity in certain cases of relapsed AML. 1,2 Second allogeneic transplants have been offered to highly selected patients with acute leukemia that has relapsed after a prior transplant. Overall survival following a second allogeneic transplant is limited by high TRM (30-36%) and frequent relapses (44-70%). Most reports describe EFS between 14-31%.  While second transplants may be of benefit to some patients who relapse, it is clear that they are only offered to a minority. For instance, in a review of second transplants carried out for the CIBMTR by Eapen et al., only 6% of acute leukemia patients reported to the registry who relapsed received a second transplant. 11 This report clearly demonstrates that the outcome of a second transplant depends strongly on disease status at the time of second transplant, the duration of remission after the initial transplant and the age of the patient. While several reports have described the negative effect of rapid relapse after allogeneic transplant, none has been able to clearly define a true cutpoint that separates good from poor outcomes. 5,7,11,12 Results from our program, shown in the figure below, suggest that patients retransplanted within one year of an allogeneic transplant experience poor outcomes. It is reasonable to take this as a cutoff.

# Figure 1.
Outcome of second allogeneic transplants performed in Calgary for patients with AML who have relapsed following a prior allogeneic transplant. Eligible patients (top line) are those who remained in remission for > 1 year following their initial transplant.
Most reports describing the outcome of second allogeneic transplants have identified an effect of age on TRM and overall survival. None of these studies was designed to define a cut-point, and the ideal age cutoff remains unclear. The majority of these studies, however, report better outcomes for patients younger than 16 -34. 6,7,11,13 When examined in multivariate models, age usually remained a significant predictor of increased TRM and often of overall survival. Results from our program support the idea that age influences the outcome of second allogeneic transplant, with survivors of second transplants being significantly younger than those who do not survive (25.4 years vs. 40.4 years, p=0.017). In our program only 3/27 patients receiving more than one allogeneic transplant for AML experienced prolonged survival. These patients were aged 19.9, 23.8 and 31.6 years at the time of their second transplant. Within our program it would be reasonable to limit second transplants to patients below the age of 40.
Other unresolved areas include the use of reduced-intensity conditioning for patients undergoing repeat transplants. While such conditioning may result in lower conditioning-related mortality, late effects due to GVHD and infection are largely unchanged and relapse rates are higher. RIC transplants for patients with prior relapse are associated with relapse rates of between 45-70%. 12,13 Use of RIC conditioning has been associated with unfavourable outcome of second transplants in registry studies.  

# Use of Azacitidine and Donor Lymphocyte Infusions to Control Relapsed Leukemia
The impact of donor lymphocyte infusions (DLI) on relapsed leukemia was first described by Kolb and coworkers in 1990. 15 They demonstrated that patients with cytogenetic or hematological relapse of CML could achieve a second disease-free state after the infusion of lymphocytes from their original stem cell donor. Graft-versus-host disease was observed in most responders. While DLI appeared to induce durable remissions in CML, responses in acute leukemia are uncommon. Augmenting DLI with chemotherapy increases response rates but also adds toxicity, without substantially prolonging survival. One exception may be combining DLI with azacitidine, a low-toxicity alternative to higher dose chemotherapy. Two reports have been published in sufficient detail to understand the outcome of this strategy:
- The German Cooperative Transplant Study Group describe the results of a multicenter retrospective study of azacitidine plus planned DLI in 154 patients with myeloid disorders (AML (n=124), MDS (n=28) or MPN (n=2)). 16 Patients received azacitidine in a five-day 100 mg/m2 or seven-day 75 mg/m2 schedule, after which DLI was administered to 105 patients. Reasons for not administering DLI included progressive disease, coexisting GVHD, non-availability of the donor or achievement of CR with azacitidine alone. The overall response rate was 33% (27% CR, 6% PR) and two-year OS 29%. Factors associated with higher likelihood of survival include early relapse (molecular relapse only or fewer than 13% blasts at time of relapse) and a diagnosis of MDS. GVHD occurred in 31%. Given that some patients received the azacitidine+DLI for molecular relapse only and thus some of them may have been cured ever without the azacitidine+DLI, it is unclear whether this therapy has a meaningful clinical efficacy. However, given the relatively low toxicity and the possibility of meaningful clinical efficacy, we are willing to offer this option to highly motivated patients. - A subset of 30 patients in the above publication were described in a previous report. 17 These patients received azacitidine 100 mg/m2/day for five days every four weeks with escalating DLI after every second cycle. Twenty-two patients received DLI and seven (23%) achieved CR and two (7%) PR. Patients with MDS, AML with MDS-related change, early relapse and high-risk cytogenetics were more likely to show response.
We will use the following schedule:
- This protocol was adopted by the Alberta Blood and Marrow Transplant Program for treatment of relapsed AML and MDS in 2017. Since that time we have treated 13 patients with mixed results. Median follow-up of surviving patients is 720 days, range 102-1202 days. Median overall survival for the entire cohort is 185 days with 43% of patients alive at one year. Three-year overall survival is 16%. It is notable that none of the patients in this series was positive for FLT3 mutations.

# Indolent Diseases: Chronic Myelogenous Leukemia (CML) and Chronic Lymphocytic Leukemia (CLL)
In the case of CML and CLL, the risk of recurrence is related to the status of the disease at the time of transplantation. Outcomes of transplantation for CML beyond first chronic phase or for CLL that has transformed to aggressive lymphoma remain inferior to those of less advanced disease. Outcomes of transplantation for CLL with adverse cytogenetics (17p-, 11q-), advanced stage at diagnosis or that is fludarabine-refractory are inferior to those of patients without these features. 18 Lu 18 The management of relapsed CML and CLL after transplant should take into account prior therapies the patient has received and the existence of newer therapies that the patient may not have been exposed to prior to undergoing transplant. In CML, later-generation tyrosine kinase inhibitors (dasatinib, nilotinib, bosutinib and ponatinib) may not have been available to the patient prior to transplant. Similarly, in CLL, patients may not have received B-cell receptor antagonists (ibrutinib or idelalesib) or a BCL-2 inhibitor (venetoclax). It is reasonable to use these agents in the posttransplant relapse setting if the patient has not previously been exposed.
The existence of an immunological graft-versus-leukemia effect in these diseases is well described. In both diseases relapses are more common using T-cell depleted grafts, relapses are less common once chronic GVHD develops, responses are delayed and tend to deepen over time. Donor lymphocyte infusions (DLI) are a practical way of exploiting this graft-versus-leukemia effect, although they are not without significant toxicities of their own. The majority of patients who respond to DLI develop some degree of acute or chronic GVHD and 8% of patients treated with DLI develop aplasia and may require retransplantation.
The table below summarizes the response of relapsed CML to DLI. While responses are seen in the majority of patients with early relapse, responses in accelerated phase disease are more the exception than the rule. Similar results are observed in CLL, although large series have not been published to date. The existing literature suggests that 44 -86% of patients with relapsed CLL will respond to DLI, and this response may be enhanced by the addition of rituximab. 19,20  CML, the addition of TKI's or interferon may enhance response to DLI, while in CLL chlorambucil or rituximab may be used to delay progression of disease until a graft-versus-leukemia effect occurs. 21 Fludarabine should not be given within 48 hours of DLI as it may abrogate the allogeneic T-cell responses necessary for a graft-versus-leukemia effect to take place.  19 The literature is surprisingly silent on the topic of repeat transplantation for relapsed CML or CLL. While such transplants have no doubt taken place they are likely restricted to the small number of patients whose disease fails to respond to DLI and whose performance status, comorbidities and disease status permits. It remains uncertain what additional benefit is to be derived from retransplantation in the setting of disease that fails to respond to the graft-versus-leukemia effect engendered by DLI. - If blood cultures negative but persisting fever or patient clinically unwell, continue antibacterials until ANC 0.5/nl for 2 consecutive days.
- If blood culture negative, afebrile, and clinically well after 72 hours, discontinue antibacterials.
- Empirical anti-fungal therapy should be considered in patients who have persistent or recurrent fever after 4-7 days of treatment with broad spectrum antibacterials. (See chapter on Fungal prophylaxis).

# Definitions
Fever: single core temperature of  38.5C (or oral > 38.3), or a core temperature of  38.3C (or oral>38.0) sustained over a 1 hour period.
Neutropenia: an absolute neutrophil count of <0.5/nl, or an ANC that is expected to decrease to <0.5/nl during the next 48 hours.

# Investigations
In addition to a focused history, review of systems and physical examination, all patients with fever in neutropenia should be investigated as follows:
Last Revised: December 14, 2021 Effective: December 14, 2021
- Culture specimens from other sites of suspected infection should be obtained if clinically indicated 4. If fevers persist then repeat blood cultures should be drawn every 48 hours from central line only.

# Empiric Therapy
Both ASCO (American Society of Clinical Oncology) and Surviving Sepsis campaigns recommend TTA (time to antibiotic) of < 60minutes.

# Stable Patients
- Piperacillin/tazobactam at 4.5 grams every 6 hours 2. Ceftazidime/Cefepime 2 grams q8h is given to patients who may have allergy to penicillin, recognizing that 5% of patients may still cross react. 

# Unstable Patients
Severe sepsis is a syndrome defined by evidence for SIRS (systemic inflammatory response syndrome) (defined by  two of the following criteria):
- body temperature > 38C or < 36C,
- heart rate > 90 beats/minute,
- respiratory rate > 20/minute, - Pa CO2 < 32 mmHg,
- an alteration in the total leukocyte count to > 12  10 9 /L or 10% band neutrophils in the leukocyte differential - PLUS evidence of infection and end-organ dysfunction (altered mental status, hypotension (systolic blood pressure  40 mmHg,) elevated serum lactate >4 mmol/L, oliguria (urine output <0.5 mL/kg/hour), and/or hypoxia.
Patients with sepsis or pneumonia with bacteremia have mortality >50% despite prompt antibiotics. Aggressive fluid resuscitation, oxygen and early physiological goal directed therapy, including ICU support, is critical. - There is no proven advantage to adding vancomycin empirically in the setting of persistent or recrudescent fever and neutropenia in an otherwise asymptomatic hemodynamically stable patient. If vancomycin was added empirically at the outset of therapy for neutropenic fever, it should be stopped if blood cultures have incubated for 48 hours and demonstrated no pathogenic gram-positive organisms.

# Re-Assessment
Patients are reassessed for response to treatment daily. Antibacterial coverage is adjusted to ensure coverage of organisms grown in culture, preferably based on in vitro sensitivity testing.

# De-Escalation
Aguilar-Guisado and colleagues performed an open-label randomized trial to evaluate outcomes of deescalation of empiric antibacterial therapy in neutropenic patients with fevers. 11 In this study, adult febrile neutropenic patients with hematologic malignancies or HCT with no identified microbiologic source of fever were randomized to receive antipseudomonal therapy until the ANC was >0.5/nl versus early discontinuation of antipseudomonal therapy after 72 hours or more of being afebrile with clinical improvement, despite ANC <0.5/nl.
Patients in the early discontinuation group had fewer days of empiric antimicrobial therapy administration and no significant increase in mortality or days of fever compared with the standard-ofcare group. Although patients in the early discontinuation group experienced more adverse events, a majority were mild to moderate and included mucositis, diarrhea, nausea, and vomiting.
This study provides data that neutropenia with no documented bacterial infection and no fever for 48 hours or more can be discontinued or stepped down from anti-pseudomonal therapy. Limitations of the study in relation to our situation are that only ~10% patients were HCT recipients (~5% auto and ~5% allo) and that the median number of days before neutropenia onset was only ~2 days (range, 1-7 days).   - The recommended catheter for patients undergoing apheresis is the medCOMP 12.5F double lumen silicone Hemo-Cath catheter, and is to remain in place until after autologous transplant.
- If apheresis is not necessary, a flexible triple-lumen catheter as recommended for allogeneic transplant is acceptable, or a silicone double lumen groshong peripherally inserted central catheter (PICC)
Allogeneic Transplant Recipients:
- The recommended catheter used for allogeneic transplantation is the Bard 12.5Fr triple-lumen Hickman silicone tunneled catheter (Product Code: #0600650 -lumen diameter red 1.5mm, blue 1.0mm, white 1.0mm).
- Non-rigid 12.5F catheters are preferred for patient comfort.

# Healthy Donors:
- Peripheral venous access is preferred for collection from healthy donors. Two large-bore antecubital lines will be inserted just prior to apheresis.
- If large bore antecubital lines cannot be inserted a double-lumen Quinton Mahurkars (8 French diameter, length 15 cm) will be inserted under image guidance and removed prior to the patient leaving the hospital.

# Chimeric antigen receptor T-cells (CAR T-cells) recipients:
- A flexible triple-lumen catheter as recommended for allogeneic transplant is acceptable

# Prevention of CVAD Infections
- The central venous catheter care clinical bundle (including hand hygiene, maximal barrier precautions, and chlorhexidine skin antisepsis) will be used for placement and maintenance of all CVADs.
- Rigorous attention to hand hygiene and aseptic technique is essential before inserting, removing, or manipulating the CVAD.
- Prepare clean skin with a >0.5% chlorhexidine preparation with alcohol before CVAD insertion and during dressing changes.
- Use sterile gauze or sterile, transparent, semi permeable dressing on CVAD insertion site. For tunneled CVADs, dressings may be removed as per unit policy and procedure.
- Promptly remove CVAD lines that are no longer being used. - Insert CVAD on right side. Avoid femoral vein.
- Remove CVAD if not used or used infrequently.

# Treatment of CVAD Infections Empiric Treatment:
- Collect bacterial cultures from CVAD entrance/exit site and blood (central and peripheral) prior to initiating treatment.
- Vancomycin to cover Staphylococcus aureus, coagulase negative Staphylococcus and Enterococcus sp. (MRSA circulates rarely on our BMT unit).
- In severely ill patients, cover also Gram-negative bacilli including Pseudomonas (Tazocin, ceftazidime or meropenem).

# Treatment of Proven or Complicated Infection:
- Treat according to IDSA guidelines as described in main text below.

# Treatment of Line Occlusion (Thrombotic or Mechanical)
- Thrombotic occlusion will be treated with r-tPA.
- Unless mechanical occlusion is suspected radiographic imaging is not necessary prior to r-tPA instillation.
- If a mechanical issue is suspected or signs of tip malposition an x-ray and/or dye study will be carried out.
- For chemical occlusion consult Advanced Venous Access Service (AVAS) for assessment.

# Treatment of Line Related Venous Thrombosis
- There is insufficient evidence to recommend routine removal of clinically-necessary, functioning and non-infected CVAD's in the setting of catheter-related thrombosis. If anticoagulation is not feasible then line removal is indicated.
- Anticoagulation should be continued at least for the duration of line placement if removal is not feasible.
- Anticoagulation duration is controversial and CVAD catheter-related thrombosis should be treated as per established guidelines for DVT.
- Catheter-related thrombosis should be treated as a provoked thrombosis and treated with anticoagulation for 3 months.
- Patients whose lines have been removed and who experience bleeding complications while on anticoagulation may be taken off of anticoagulation before completing 3 months of treatment provided symptoms of catheter-related thrombosis have resolved. They should be reimaged in 10-14 days to exclude propagation of venous thrombus if anticoagulation is discontinued early.
- Patients with active malignancy should receive anticoagulation with low molecular weight heparin until complete remission has been achieved.
Last Revised: April 13, 2021 Effective: April 13, 2021
- Tinzaparin 175 IU/kg once daily may provide easier and more reliable anticoagulation compared with warfarin in patients taking multiple interacting medications, antibiotics and/or with unpredictable dietary intake. Caution should be exercised when using low molecular weight heparins in individuals with impaired renal function. Caution should also be used with direct oral anticoagulants (DOAC) due to drug interactions.

# Background
Multi-lumen catheters are placed prior to transplant to facilitate transfusions, blood draws and medication administration and are preferably tunneled to decrease infection risk.

# Line Type Preferences
Autologous Transplant Recipients:
- For autologous transplantation, a rigid line is needed for apheresis/stem cell collection. The current recommended catheter used prior to apheresis is the medCOMP 12.5F double lumen silicone Hemo-Cath catheter, and is to remain in place until after autologous transplant.
- 4% sodium citrate is instilled in all lumens of the CVAD four to six days prior to autologous stem cell collection
- If a patient has had a previously installed implanted vascular access device (IVAD), it need not be removed prior to transplant but another catheter may also be placed.
- If apheresis is not necessary a flexible double or triple (preferred) lumen catheter is acceptable for transplant (same as for allogeneic transplantation).
- If a peripherally inserted central catheter (PICC) line will be used for transplant instead of a tunneled central line a Bard Groshong silicone PICC line should be used instead of a polyurethane PICC (e.g. Power PICC SOLO). ABMTP (Alberta Bone Marrow Transplant Program) has experience infusing dimethyl sulfoxide through a silicone line but not a polyurethane line.

# Allogeneic Transplant Recipients:
- In allogeneic transplantation, a large bore, triple lumen catheter is preferred for transfusions and medication administration.
- The current recommended catheter used for allogeneic transplantation is the Bard 12.5Fr Triple Lumen Hickman silicone tunneled catheter (Product Code: #0600650 -lumen diameter red 1.5mm, blue 1.0mm, white 1.0mm).
- Non-rigid 12.5F catheters are preferred for patient comfort (i.e. Raff, Bard)
- If a PICC line needs to be inserted pre transplant or while a patient is on IVPB cyclosporine a Bard Groshong silicone line should be used instead of a Power PICC Solo polyurethane catheter. ABMTP has experience infusing DMSO, busulfan, cyclosporine through a silicone line but not a polyurethane line.
Last Revised: April 13, 2021 Effective: April 13, 2021
Healthy Donors:
- Two large bore antecubital lines are to be inserted.
- If large bore antecubital line insertion is not possible or donor is unwilling a double lumen Quinton Mahurkars (8 French diameter), length 15 cm, is inserted the day of collection to facilitate apheresis and then removed post apheresis.

# Chimeric antigen receptor T-cells (CAR T-cells) recipients:
- A flexible triple-lumen catheter as recommended for allogeneic transplant is acceptable

# Complications Associated with Central Venous Catheters
Bleeding Following Insertion
- The bleeding risk associated with insertion of a tunneled central line is variable and depends on coagulative function as well as operator experience and skill.
- To minimize bleeding risk for line insertion, ensure platelets >50 and INR <1.4 prior to line insertion, or as specified by radiologist.
- Avoid high dose heparin.
- Bleeding can be managed with local pressure to site, hemostatic dressing, reversal of anticoagulation (i.e. heparin from line, PT and PTT must be checked), clotting factors if necessary, tranexamic acid.
- Rarely, surgical intervention may be required to repair site.
Abbreviations: INR = international normalized ratio; PT = prothrombin time; PTT = partial thromboplastin time.

# Catheter-Related Infections
Catheter-related infections are important causes of morbidity, mortality and health care costs, with an infection rate of approximately 5 per 1000 catheter days in the critical care population. In a metaanalysis of 2573 catheter-related blood infections, case-mortality rate was 14% with 19% of deaths due to catheter-related infection. 1 Mortality was the highest with Staph. aureus at 8.2% and lowest with coagulase negative Staph. at 0.7%. 1 Skin organisms predominate in the first few weeks as they migrate into the catheter tract and cause tip infections. In long term catheters, hub infections become a more common source. Line infections can also result from hematogenous seeding from other sites.
- Peripheral IV -0. Catheters made of Teflon, silicone elastomer, or polyurethane are less likely to cause infection than catheters of polyvinyl chloride or polyethylene. 2,3 Surface irregularities enhance the microbial adherence of some organisms (i.e. coagulase negative Staph., Acinetobacter calcoaceticus, Pseudomonas aeruginosa). Some catheters are also more thrombogenic, which can contribute to subsequent infections. Host factors can be important; for example Staph. aureus adheres to proteins such as fibronectin that are commonly present on catheters and this can make infection difficult to clear. In addition, coagulase negative Staph. adheres well to polymer surfaces and can produce an extra cellular polymer "slime" which allows it to withstand host defences by killing neutrophils and acting as a barrier to antibiotics and phagocytes. Candida can also produce slime in presence of glucose-containing fluids, which may contribute to increased fungal infections in people on total parenteral nutrition. The most common organisms cultured from patients with central line infections are as follows: 4 - Coagulase negative Staphylococcus (50%)
- Gram negative organisms (20%)
- Increasing third generation cephalosporin resistance in E.coli and Klebsiella, increasing imipenem and ceftazidime resistance among pseudomonas aeruginosa
- Staphylococcus aureus (30%) o Rare MRSA

# History Suggesting Catheter-Related Infection:
Components of the patient history supporting the presence of a catheter-related infection include continuous or persistent bacteremia, sepsis after infusing through a line, blood cultures of organisms known to colonize/infect lines, catheter thrombosis, clinical improvement with catheter removal, and the lack of another clinical source of infection. Physical exam findings are unreliable but can include fever, shock or inflammation/purulence at the exit, entrance or tunnel site.

# Diagnostic Tests:
If a catheter-related infection is suspected, the following tests should be ordered:
- Gram stain and culture of exudate if present - Culture of line tip if removed (best if plated at bedside) 5 o Positive result when >15 colony-forming units present on tip - Central and peripheral blood cultures drawn prior to antibiotics (min 10 mL/bottle, yield increases 3% per additional mL blood up to 20 mL) o A difference in the time to positivity of 120 minutes between centrally-and peripherallydrawn blood cultures is 91% sensitive, and 94% specific for catheter infection - If the infection occurred within 48 hours after insertion initiate "FMC DI/IP&C/BMT/Hematology Cluster Investigation Form for CVAD Insertion Related Infections".
Prevention of CVAD Infections (Adapted from IDSA Guidelines) 2
- Rigorous attention to hand hygiene and aseptic technique is essential before inserting, removing, or manipulating the CVAD.
- Prepare clean skin with a >0.5% chlorhexidine preparation with alcohol before CVAD insertion and during dressing changes.
- Evaluate the catheter site daily by palpation through the dressing for tenderness and by inspection if transparent dressing; if opaque dressing this does not need to be removed.
- Consider removal of CVAD if intraluminal catheter thrombosis cannot be corrected - Promptly remove CVAD lines that are no longer being used, non-functional or bulging.

# Treatment of CVAD Infections
Definite indications for tunneled catheter removal are as follows: 7
- Complicated infections (septic thrombosis, endocarditis, osteomyelitis, possible metastatic seeding).
- Tunneled catheter pocket infections or port abscess.
- Persistently positive cultures or persistent fever (>72 hours) while on treatment for a known line infection
- Relapse after antibiotics are discontinued.
- Fungal catheter-related blood infection, candida, mycobacteria, Pseudomonas aeruginosa, Staph. Aureus.
There should be a low threshold for catheter removal with catheter related blood stream infections including Burkholderia cepacia, Actinobacter baumannii, Stenotrophomonas species, Bacillus species, and Corynebacterium species. For coagulase negative Staph. bacteremia, recurrence by 12 weeks was seen in 20% of patients with line salvage versus 3% with line removal; another study found Staph. aureus patients were 6.5 times more likely to relapse or die of infection without line removal (studies were done without antibiotic lock therapy). 7,8 Reinsertion of central lines should be postponed until after serial negative blood cultures are obtained; although not always practical, this is ideally done after negative blood cultures are obtained 5-10 days after completion of antibiotics.
There are limited prospective randomized controlled trials examining the optimal treatment choices and duration of therapy for CVAD infections. Based largely on published guidelines, the following empiric therapy is suggested 7 :
- Vancomycin in hospitals/areas with MRSA; if resistance to vancomycin is seen, daptomycin is the alternative and linezolid is not indicated as empiric therapy for CRBSI (catheter-related bloodstream infection) is not feasible. Ethanol locks have also been associated with decreased primary catheter related bloodstream infections.

# Specific Management Challenges

# Staphylococcus aureus:
- Staph. aureus bacteremia is associated with a high risk of metastatic infections and provides a management challenge (25% -32% occult endocarditis in patient with staph aureus bacteremia), hematogenous complications in 25-30%.
- Beta-lactam drugs (cloxacillin or cefazolin) are preferred therapy if the Staph. aureus is sensitive.
- If the bacteremia is not cleared by 72 hours after antibiotics, long-term therapy is required (minimum 4 weeks). 5
- Non-tunneled catheters should be removed.
- Tunneled catheters should be removed, and must be removed in the presence of abscess or tunnel site infection.
- Search for metastatic infection is indicated, starting with a TTE (transthoracic echocardiography) if there are no contraindications, and clinical monitoring for osteomyelitis, septic arthritis, and other sites of infection.
- ID consultation will likely be needed.

# Enterococcus:
- Ampicillin is treatment of choice +/-gentamicin; vancomycin in cases of ampicillin resistance.
- Daptomycin in cases of VRE (vancomycin-resistant Enterococcus) based on susceptibility.
- Line removal is preferred. Lines should be removed in the case of vancomycin resistant species.

# Fungal infections:
- If there is documented catheter-related fungal infection, the CVAD should be removed. 7,10 - Antifungal therapy should continue until 14 days after last positive blood cultures and signs/symptoms resolved.

# Septic thrombophlebitis:
- The most common organisms implicated in septic thrombophlebitis are Staph. aureus, Candida species and gram negative bacilli; the presence of thrombus greatly increases the risk of CVADrelated infections.
- In the presence of septic thrombophlebitis, the catheter should be removed.
- Surgical consultation is indicated in the case of suppurative thrombophlebitis, infection persists on antibiotics or there is pseudo aneurysm formation.
- Routine anticoagulation of patients with septic thrombophlebitis is not recommended. It can be considered for selected patients, such as those who are highly symptomatic of their thrombosis.
- Thrombolysis is not indicated. Infectious disease consultation is suggested. 

# Catheter-Related Thrombosis or Mechanical Occlusion

# Line Occlusion

# Thrombotic occlusions:
- Occluded CVADs should be treated with r-tPA.
- Unless mechanical occlusion is suspected radiographic imaging is not necessary prior to tPA instillation.
- 2 mg alteplase (Cathflo) is reconstituted with 2.2mL sterile water by a certified RN. As much as possible up to 2mg is instilled into the blocked CVAD lumen and as per nursing procedure.
- Place r-tPA into lumen for 2-24 hours then aspirate. R-tPA can be aspirated after 30 minutes if line access is urgent.
- Can be repeated x1 if unsuccessful; tPA can be left in situ overnight. 

# Mechanical occlusions:
- If line patency is not restored, consider consulting interventional radiology (line stripping, TPA drip in IR). If this is unsuccessful the line is to be removed as soon as safe to do so.

# Catheter-Related Venous Thrombosis
The incidence of symptomatic catheter-related deep vein thrombosis (DVT) in patients with malignancies is approximately 3-4%, although ultrasound surveillance documents clots in about 12% of patients. 11 A small series in bone marrow transplant patients showed an incidence as high as 50% although the majority were asymptomatic. 12 Risk factors include malplacement of the catheter, >1 insertion attempt, a previous CVAD, placement of the catheter on the left-hand side and malignancy. Symptoms that suggest an upper extremity DVT include erythema and swelling (which may be exercise-dependent or gravity-dependent), and pain or tenderness at the base of the neck, superclavicular fossa, arm or shoulder. Collateral blood flow often develops and vessels may be visible. Embolization is the major cause of morbidity and mortality, and pulmonary embolism (PE) occurs in up to 20% of patients with symptomatic thrombosis. The following tests may confirm the diagnosis:
- Ultrasound or venogram of extremity - If symptoms of respiratory compromise/pulmonary embolism, workup requires a PE protocol CT scan or V:Q scan; rarely pulmonary angiogram is indicated

# Prophylaxis of CVAD-related Thrombosis and Deep Venous Thrombosis
- DVT prophylaxis should be carried out as per established guidelines for the medical patient in the absence of significant bleeding, coagulopathy or thrombocytopenia (platelets < 50). 12 Options for thromboprophylaxis include low-dose unfractionated heparin, low molecular weight heparin or mechanical prophylaxis.
- Mobilization should be encouraged - Use of anticoagulation for routine prophylaxis of catheter-related thrombosis is not recommended.  

# Treatment of CVAD-related Thrombosis and Deep Venous Thrombosis
- There is insufficient evidence to recommend routine removal of clinically-necessary, functional and non-infected central lines in the setting of catheter-related thrombosis.
- Anticoagulation should be continued for the duration of line placement if removal is not feasible.
- Anticoagulation duration is controversial and catheter-related thrombosis should be treated as per established guidelines for provoked DVT. 12, o Catheter-related thrombosis should be treated as a provoked thrombosis and treated with anticoagulation for a total of 3 months. o Patients whose lines have been removed and who experience bleeding complications while on anticoagulation may be taken off of anticoagulation before completing 3 months of treatment provided symptoms of catheter-related thrombosis have resolved. They should be reimaged in 10-14 days to exclude propagation of venous thrombus if anticoagulation is discontinued early. o Patients with active malignancy should receive anticoagulation with low molecular weight heparin until complete remission has been achieved. o Tinzaparin 175 IU/kg once daily may provide easier and more reliable anticoagulation compared with warfarin in patients taking multiple interacting medications, antibiotics and/or with unpredictable dietary intake. Caution should be exercised when using low molecular weight heparins in individuals with impaired renal function. 

# Summary
- Established cirrhosis is associated with high risk of severe veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS), multiorgan failure, and death in recipients of HDCT/BCT. Myeloablative stem cell transplantation will not be offered to this group of patients. Potential options for reduced intensity conditioning may be explored.

# Viral Hepatitis
- All recipients and donors will be screened for hepatitis B and C, with further viral load/nucleic acid testing (NAT) required for those with a positive screening test.
- Hepatology referral for assessment and peri-transplant management is required for patients with chronic active hepatitis B or positive hepatitis C serology, and donors who are HBV NAT positive.
- Recipients with past hepatitis B infection (surface antigen negative, core antibody positive) should receive prophylactic antiviral therapy and undergo regular viral load testing as directed by Hepatology
- Use of mycophenolate mofetil (MMF) has been linked to developing fibrosing cholestatic hepatitis and should not be used in HCV-infected patients.
- Long-term risks of developing cirrhosis and HCC appear to be similar to non-HSCT population with HBV.
- HCV infection in HSCT population is associated with increased risk of morbidity (e.g. early cirrhosis, GVHD, VOD/SOS) and mortality (e.g. fatal VOD/SOS, excess bacterial infection, fibrosing hepatitis) compared to non-HSCT population.

# Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome (VOD/SOS)
- Ursodiol 15-20 mg/kg/day will be given for the first 80 days post-transplant for prophylaxis of VOD/SOS in allogeneic HCT recipients.
- SOSVOD should be suspected clinically in the patient with weight gain, hyperbilirubinemia, hepatomegaly, +/-ascites early post transplant. The diagnosis should be confirmed by ultrasound, liver biopsy or measurement of hepatic vein wedge pressure gradient if possible.
- Standard treatment of SOS/VOD is supportive, with careful attention to fluid balance and renal perfusion and elimination of hepatotoxic medications. 

# Background
Prior to universal screening of blood products, viral hepatitis was very common among BMT recipients. In one Italian program, Locasciulli et al. reported that 30 of 145 (21%) consecutive BMT recipients were positive for HBsAg. 1 A high risk of hepatitis C from unscreened blood products has also been reported by Strasser et al., with a risk of hepatitis C of 17% prior to transplant and 32% by day 100. 2 Universal screening of blood products in recent years has reduced the risk of hepatitis B transmission to 1 in 1.7 million and the risk of hepatitis C transmission to 1 in 13 million per screened unit. Currently, the majority of viral hepatitis in BMT recipients is likely acquired from other sources.

# Hepatitis C
The hepatitis C virus is a single-stranded RNA virus. Transmission is most effective by direct bloodto-blood inoculation. The incubation period is 6 -12 weeks, followed by a generally mild, self-limiting hepatitis. 85% develop chronic infection, and of these 20% will develop cirrhosis and 5% will die of liver failure or hepatocellular carcinoma (HCC).
The course of hepatitis C after BMT appears to be generally mild. While some reports suggest an increased rate of severe veno-occlusive disease (VOD) in BMT recipients who are positive for the hepatitis C virus (HCV), most suggest that the risk is not substantially higher than in HCV-negative recipients. Strasser et al. reported the results of BMT in patients who were HCV-positive at the time of transplant, and they found the risk of severe VOD in HCV-positive patients was 48%, compared with 14% in HCV-negative control patients. 2 The risk of VOD was only increased in this report if patients had elevations of ALT at the time of BMT. Most other reports suggest that the rate of VOD in patients with HCV is approximately 8%, roughly that seen in HCV-negative recipients. 3 Over the long term, patients with hepatitis C do show features of mild, chronic hepatitis after BMT. AST levels are generally higher for 5 to 10 years, although the risk of fulminant hepatic failure (FHF) is not increased. There does not appear to be excessive mortality in long-term (> 3 years) survivors who are HCV+.
Patients with hepatitis C who undergo BMT do appear to be at higher risk of developing cirrhosis than similar patients who do not undergo BMT. As shown in the figure below, in one series measuring time to progression to cirrhosis (from time of infection with HCV), the median time to cirrhosis was 18 years in BMT recipients versus 40 years in non-transplant patients. 4 The cumulative incidence of cirrhosis in transplanted patients was 24% at 20 years.
A recent European prospective trial of 195 patients who had undergone stem cell transplant (134 allogenic, 61 autologous hematopoietic HCT) demonstrated an overall survival probability of 82% and 6.1% death rate due to liver disease. The rate of decompensated liver disease and death was 12% at 20 years post transplant. HCV infection was associated with increased risk of morbidity and mortality while treatment was associated with improved outcomes. 5 

# Hepatitis B
Worldwide, over 350 million people are hepatitis B virus (HBV) carriers. In general, hepatitis B runs a more aggressive course than hepatitis C. Risk of cirrhosis in patients with hepatitis B is between 12 and 23%, and the risk of decompensation or HCC is between 6 and 15%. As shown in the figure below, Hepatitis B proceeds in a two-stage process: first infection/replication, then immune reaction. It is the immune reaction that is responsible for many of the clinical features of acute infection.

# Figure 2. Hepatitis B and BMT
Hepatitis B does not appear to increase the incidence of VOD after transplant. VOD is reported to occur in approximately 8% HBV-exposed recipients. The incidence of serious liver disease is increased in HBV carriers after BMT. Chen et al. reported that 81% of hepatitis B carriers developed impaired liver function after a median follow-up of 68 months from alloBMT. 6 In addition, 12% developed FHF (median day+170) post BMT. The risk of chronic hepatitis (19.5% versus 0.3%, p<.001) and cirrhosis (9.8% versus 0%, p<.001) are also higher in these patients. 7 The risk of cirrhosis is comparable with untransplanted patients with HBV. Sustained clearance has been reported in HBsAg+ recipients receiving transplants from donors with natural immunity to HBV. 7,8 Last Revised: May 11, 2021 Effective: May 11, 2021 

# Transient Elastograpy (i.e. FibroScanTM)
Transient elastography is a non-invasive test of liver stiffness which uses a vibrating ultrasound probe to transmit a sheer wave into the liver. The rate at which the vibrating pulse returns to the probe from the liver is directly proportional to the stiffness of the liver; stiffness in this context correlates to the degree of fibrosis. A liver stiffness of less than 11 kPa makes cirrhosis unlikely. 10 Transient elastography is of limited utility in morbidly obese patients and patients with ascites. Liver biopsy may still be required to clarify the degree of fibrosis.

# Treatment of Viral Hepatitis
Treatment of chronic viral hepatitis has improved significantly over the past decade. Newer antiviral agents, as well as novel preparations of old agents, have significantly improved the management of these diseases. Management of patients with chronic active hepatitis is best done under the guidance of an experienced Hepatologist.
Lamivudine, a nucleoside analogue antiviral medication originally described as treatment for HIV infection, has shown considerable activity in hepatitis B. Lai et al. reported that among non-transplant patients, treatment with lamivudine was associated with normalization of ALT in 72% and a 98% reduction in HBV DNA after 1 year. 11 In the non BMT population, lamivudine is not favoured given its high rate of resistance approaching 70% at 4 years. Higher success rates of viral clearance are seen with the use of tenofovir or entecavir with DNA levels dropping by 6-7 log after 1 year of treatment. 12 In BMT, lamivudine has been reportedly used in three Japanese autologous peripheral blood stem cell transplant recipients. 14 No effects on engraftment or stem cell collection were noted and HBV DNA remained negative. Lamivudine has also been reported in combination with recipient vaccination in 29 recipients of HBsAg+ marrow (comparison group of 25 historical controls). Rates of HBV hepatitis (48% versus 6.9%, p=.002) and HBV FHF (24% versus 0%, p=.01) were substantially reduced by treatment with lamivudine. The role of passive immunization with hepatitis B immunoglobulin is unclear, but this strategy is not likely to result in sustained benefit.
Newer antiviral agents of use in hepatitis B include tenofovir and entecavir. These agents rapidly suppress viral replication and so result in rapid suppression of the hepatitis B viral load. limited data on the use of these newer agents in patients undergoing stem cell transplantation although small case series have demonstrated good outcomes. 15,16 The interferons are a group of cytokines that exhibit a broad range of antiviral and immunomodulatory activities. Pegylated interferon, in combination with ribavirin, results in sustained clearance of hepatitis C and serum ALT responses in 50-75% of immunocompetent patients depending on the genotype Because of concern over the use of immunomodulatory and myelosuppressive agents in the BMT population, there are relatively few reports of interferon therapy for hepatitis C in BMT recipients. One case series, reporting results in 11 patients with thalassemia who underwent BMT, suggests that this treatment is safe and of similar efficacy compared with non-BMT patients (negative HCV viral DNA in 5/11) after 6 to 12 months of treatment. 17 Treatment was delayed 2 to 5 years after BMT to allow for reestablishment of marrow reserve. Treatment of 4 HCV-positive allogeneic BMT recipients with single-agent ribavirin has also been described by Ljungman et al. 18 In this series, 1 patient died early while 2 showed clearance of HCV DNA. There were no adverse effects attributable to ribavirin in this small report.
Over the past 5 years, treatment of chronic HCV infection in patients with hematologic malignancies has evolved rapidly as safe and effective direct-acting antivirals (DAAs) have become the standardof-care treatment. The American Society of Blood and Marrow Transplantation (ASBMT) recommends a complete course of therapy with DAAs prior to transplantation, if clinically feasible 19 . If DAA treatment cannot be completed until after HSCT, DAA therapy can be deferred until after immune reconstitution except in patients who develop fibrosing cholestatic hepatitis C and cases of severe HCV reactivation post transplant. Due to drug-drug interactions (e.g. calcineurin inhibitors), deferring until 6 months after HSCT to start DAA therapy may be considered. Preliminary data show that DAAs are safe and effective, with sustained virologic response (SVR) rate of 85% in HCVinfected HSCT recipients 20 . In this study, patients who received antiviral treatment (AVT) had fewer relapses of HCV-associated non-Hodgkin lymphoma (20% vs. 86%, p=0.015), higher 5-year survival rate (75% vs. 39%, p=0.02, and a trend toward lower rate of progression to cirrhosis (5% vs. 21%, p=0.06). AVT discontinuation post-HCT was 71% in those receiving interferon-containing regimens and 0% in those receiving DAAs (p<0.01). AVT was effective in 12/37 (32%) and 11/13 (85%) of patients receiving interferon-based and DAA regimens, respectively (p=0.003). The timing and choice of DAA regimen needs to be individualized, taking into account urgency of transplant, treatmentlimiting co-morbidities, HCV genotype and degree of liver disease, and potential for hematologic toxic effects and drug-drug interactions. The website  provides continuously updated guidelines for DAA treatment of patients with HCV infection. In both the liver transplant and HCT settings, use of mycophenolate mofetil has been linked to development of fibrosing cholestatic hepatitis C, thus this drug should not be used in HCV-infected patients 21 .
Veno-Occlusive Disease/ Sinusoidal Obstruction Syndrome (VOD/SOS) Hepatic veno-occlusive disease (VOD), increasingly referred to as sinusoidal obstruction syndrome (SOS), is a well-recognized complication of all stem cell transplantations, irrespective of the stem cell source, type of conditioning therapy, or underlying disease. Although the incidence has decreased in recent years, it is still between 5 and 15% for myeloablative transplants and up to 5% after RIC alloHCT. The table below describes the patient, disease, and transplant factors associated with SOS. The diagnosis of SOS has traditionally used either the Seattle Criteria 22 or the Baltimore Criteria 23 (see Appendix 1).The Baltimore criteria is more specific and less discrepant when corroborated with histopathology and hemodynamic studies, particularly for classic SOS/VOD (onset 11.1 gm/l). The use of transvenous liver biopsy has been shown to confirm diagnosis or reveal an alternate diagnosis in the majority of cases of early posttransplant liver disease. Shulman et al. reviewed 60 BMT patients with liver dysfunction who underwent transvenous liver biopsy and measurement of the hepatic venous pressure gradient 25 .The wedged hepatic venous pressure gradient > 10 mmHg correlated with a histologic diagnosis of SOS (p =0.001), and this gradient value provided 91% specificity and 86% positive predictive value. Bleeding complications were reported in 11 cases, and there were 3 procedure-related deaths.
Prior to assuming SOS however, it is important to consider and rule out: congestive heart failure, fungal or viral liver infections, sepsis-or drug-induced cholestasis, and tumour infiltration of the liver.
In order to promote earlier therapeutic intervention, the EBMT also proposed criteria for severity of grading of SOS/VOD once the diagnosis was made 24 (Table 4). Four stages of severity (mild, moderate, severe, and very severe) are based on five parameters: time since first clinical manifestation of SOS/VOD, bilirubin level and kinetics, transaminase level, weight gain, and renal function. Importantly, in the presence of two or more risk factors, patients are classified in the upper grade. These criteria were validated in a study of 203 patients with SOS/VOD 26 : 5.9% were mild, 12.8% moderate, 18.2% severe, and 63.1% very severe; the day 100 OS of these groups were 83.3%, 84.3%, 94.6%, and 58.6%, respectively. The day 100 TRM was significantly higher in very severe SOS/VOD at 36.7%, compared to 8.3% in mild, 8.0% in moderate, and 2.7% in severe (p<0.0001) 26 . Treatment of VOD/SOS Defibrotide (DF) is the only agent with proven efficacy for the treatment of severe/very sever SOS/VOD. Defibrotide is a single-stranded polydeoxyribonucleotide that has anti-inflammatory and antithrombotic properties. Richardson et al. reported on the use of defibrotide in 88 patients who developed severe SOS and multisystem organ failure after stem cell transplantation 27 . The patients ranged in age from 8 to 62 years (mean 35 years), and were assessed according to the Baltimore Criteria. Defibrotide was administered IV in doses ranging from 5 to 60 mg/kg per day for a median of 15 days. Complete resolution of SOS was reported in 32 patients (36%), with 35% survival at day +100. There was no worsening of clinical bleeding or attributable grade III or IV toxicity noted in the patients. Grade I/II toxicities included hypotension, fever, abdominal cramping, and hot 75 patients on 40 mg/kg/day of defibrotide. The 141 evaluable patients ranged in age from 0.5 to 63 years (mean 36 years), and 99% of patients were in multisystem organ failure. Complete resolution of SOS was reported in 65 patients (46%), with an overall survival rate of 42% at day +100. There was no difference in response rates between the 2 doses, but the higher dose was associated with more grade III and IV toxicities, as well as a greater risk of bleeding. Early stabilization or lower bilirubin was associated with better outcome 29 . The final results from a defribotide treatment-IND study for 1000 patients with hepatic VOD/SOS demonstrated Day +100 survival was 58.9% overall; 67.9% in pediatric patients and 47.1% in adult patients, and higher in the subgroup of patients without multiorgan dysfunction (MOD) 29 . Similarly, a systematic review of 17 defibrotide studies in the treatment of VOD/SOS demonstrated that among those treated with 25 mg/kg/day dosing the Day+100 survival rate was 56%, higher in patients without MOD at 71% vs. 44% with MOD 30 .
Given the mortality associated with severe and very severe SOS/VOD, it is mandatory to treat these patients promptly, with initiation of DF as soon as possible. Standard dosing for defibrotide is 25 mg/kg/day with recommended duration of at least 21 days and until resolution of all SOS/VOD symptoms. No dose adjustments are required with renal failure, while in obese patients corrected body weight should be used for dose calculation. In patients where such resolution happens before 21 days, it is possible to stop DF earlier (e.g. to facilitate patient discharge) with close monitoring for the rare possibility of recurrence.
The indication of DF treatment in patients with mild or moderate SOS/VOD is more questionable. In expanded/compassionate access treatment protocols, an earlier treatment initiation after SOS/VOD diagnosis was associated with higher day +100 OS (p<0.001) 31 . Up to 32% mortality was seen despite treatment, which while favorable compared to severe/very severe SOS/VOD, it remains significant. The EBMT recommends that patients who fulfill the diagnosis criteria and whose severity grading is moderate should be considered for preemptive DF and closely followed. In patients with mild SOS/VOD, supportive care should be intensified and severity criteria monitoring should be strictly applied to allow immediate DF initiation in case of deterioration. 

# Supportive Care Measures
- Careful management of fluid and sodium balance to limit third-space fluid and maintain renal perfusion.
- Limit hepatotoxic medications; wherever possible, antifungal azoles should be substituted for echniochandins
- Transjugular intrahepatic portosystemic shunt (TIPS) may improve fluid balance and symptom control with no benefit on survival.
- While on DF, discontinue any other agents that may increase risk of bleeding.
- Nutritional support is also important, and enteral nutrition should be favored to prevent patient's malnutrition; parental nutrition is associated with fluid overload, infectious complications, and hepatotoxicity and should be avoided

# Preventative Therapy
Results of a randomized controlled trial of ursodiol for SOS prophylaxis were reported by Essell et al. 32 The patients were 67 consecutive recipients of allogeneic BMT, and they all received a busulfan plus cyclophosphamide conditioning regimen. Patients were randomly assigned to receive ursodiol, 300 mg twice daily (or 300 mg in the morning and 600 mg in the evening if body weight was > 90 kg), or placebo until day +80. The incidence of SOS was 40% (13 of 32 patients) in placebo recipients and 15% (5 of 34 patients) in ursodiol recipients (p =.03). The authors concluded that ursodiol prophylaxis seemed to decrease the incidence of hepatic complications after allogeneic BMT. A larger randomized controlled trial involving 242 patients reported no significant impact of ursodiol on the incidence of SOS, but did report significantly lower incidences of grades III and IV acute GVHD, stage II and IV liver and intestinal GVHD, and stage III and IV skin GVHD 33 . In addition, among the patients given ursodiol, the survival at 1 year was significantly better, (71% versus 55%, p=.02), and the nonrelapse mortality rate was lower (19% versus 34%, p=.01), when compared to the control group. A systematic review of three RCTs, including the two mentioned above, of ursodiol as compared to placebo demonstrated a reduced risk of SOS on ursodiol; RR 0.34, 95% CI 0.17-0.66 although no significant difference in survival 34 .
Potentially there may be a role for defibrotide as prophylaxis for SOS; a systematic review of 1230 patients from one RCT, 4 cohort studies and 8 case series studies showed an incidence of about 5% with defibrotide versus controls (14%) with a relative risk of 0.46 (95% CI 0.31-0.73) 35 . British guidelines suggest giving defibrotide at 6.25 mg/kg IV q.i.d. for prophylaxis in adults undergoing allogenic stem cell transplant with a history of pre-existing liver disease, second myeloablative transplant, allogenic transplant for leukemia beyond second relapse, conditioning with busulfan-based regimens, past treatment with gemtuzumab or inotuzumab ozogamicin, diagnosis of primary hemophagocytic lymphohistiocytosis, adrenoleucodystrophy or osteopetrosis 36 . The HARMONY clinical trial (NCT02851407) to compare efficacy and safety of defibrotide versus best supportive care in the prevention of VOD/SOS in pediatric and adult patients is continuing to recruit patients. Given that current studies in this area are limited, as well as the considerable cost and lack of access of defibrotide, further research is needed and routine use of defibrotide is not routinely recommended.

# Summary of Recommendations for Treatment of SOS
- The diagnosis of SOS should be made based on established criteria with support of ultrasound or liver biopsy if possible
- Ursodeoxycholic acid prophylaxis should be given for the first 80  Neurological Syndrome) are common after immune effector cell therapy. They should be considered in the case of fever, hypotension, organ dysfunction and unexplained neurological symptoms within 2-3 weeks of such therapies. - The ASTCT Consensus Grading system will be used to determine severity of CRS based on changes in vital signs (temperature, blood pressure and need for supplemental O2 or ventilator support). The ASTCT Consensus Grading system will be used to determine the severity of ICANS based on changes in ICE score, level of consciousness, seizure, motor findings, elevated intracranial pressure, or cerebral edema. - Management of CRS consists of antipyretics, intravenous fluids, supplemental oxygen, tocilizumab, corticosteroids, and treatment of concurrent infection. Corticosteroid prophylaxis may be considered for patients at high risk of CRS. Patients in the Intensive Care Unit will be managed concurrently by the ICU team and the Bone Marrow Transplant service.
- Management of ICANS consists of supportive care and corticosteroids. Tocilizumab may be given if there is concurrent CRS. Careful evaluation for possible metabolic, medication-associated, and infectious causes is essential, including neuroimaging and CSF evaluation when appropriate. Antiepileptic drug prophylaxis should be given to all patients with ICANS and considered from the time of CAR-T cell infusion for those at increased risk of ICANS.

# Background
A range of unique toxicities has been observed in patients treated with CAR T-cell therapy, including cytopenias, infections, and on-target, off-tumor effects such as persistent B-cell aplasia in patients treated with CD19-directed CAR T-cells. Foreign protein expressed as part of the CAR construct may on rare occasions elicit allergic reactions 1 . The most commonly observed serious toxicities of CAR Tcell therapy are Cytokine Release Syndrome (CRS) and Neurotoxicity (NT), which has also been called Immune Effector Cell-Associated Neurological Syndrome (ICANS). Although these toxicities are relatively common, when they are severe they may be life-threatening, especially if not recognized promptly and managed effectively.  Axi-cel 93% 13% 64% 28% JULIET 3 Tisa-cel 58% 23% 20% 11% TRANSCEND 4 Liso-cel 42% 2% 30% 10% ZUMA-7 5 Axi-cel 92% 6% 60% 21% BELINDA 6 Tisa-cel 61% 5% 10% 3% TRANSFORM 7 Liso-cel 49% 1% 12% 4% Mantle cell ZUMA-2 8 Brexu-cel 91% 15% 63% 31% Follicular lymphoma ZUMA-5 9 Axi-cel 82% 7% 59% 19% ELARA 10 Tisa-cel 49% 0% 37% 4% B-ALL ELIANA 11 Tisa-cel 77% 47% ICU 40% 13% ZUMA-3 12 Brexu-cel 89% 24% 60% 25% Multiple myeloma KaRMMA 13 Ide-cel 84% 6% 18% 3% CARTITUDE-1 14 Cilta-cel 95% 5% 21% 9% may be observed in this population. This may remain occult until the patient receives fluid challenges for hypotension. Pulmonary edema may occur in the context of cardiomyopathy but non-cardiogenic pulmonary edema may also occur. Hypoxia, cough and pneumonitis may also develop. Grade 3-4 hypoxia is noted in 6-15% of patients and BiPAP or mechanical ventilation may be required. Renal impairment is almost always due to hypoperfusion in the context of shock or low cardiac output. Electrolyte abnormalities are not uncommon. Tumor lysis syndrome may occur in patients with significant tumor burden at the time of treatment. Elevated liver enzymes and bilirubin may be seen in patients who develop CRS. Patients may develop nausea, vomiting, diarrhea and abdominal pain.
Cytopenias are also common after CRS. These may persist for weeks or months after treatment and should be treated supportively with transfusion and close monitoring for fever in neutropenia. It has been suggested that G-CSF should be avoided early after CAR-T cell infusion due to the potential risk of exacerbating CRS, but it can be given >14 days after CAR-T cell infusion once CRS has resolved 16 . Patients may also develop coagulopathy similar to DIC. It can often be difficult to distinguish fever from infection in this context and it is recommended that patients with CRS and clinical features of infection, including hypotension, should undergo careful screening for infection and receive treatment with antibiotics appropriate to their clinical presentation.

# General Care of the CAR T-Cell Recipient
Frequent and careful evaluation by physician and nursing staff of CAR T-cell recipients is the cornerstone of safe management of these patients. The majority of patients destined to develop CRS will do so within the first two weeks after treatment. In Calgary we plan to administer CAR T-cells in hospital. Patients will remain in hospital at the discretion of the treating physician. Grading Cytokine Release Syndrome Several CRS grading systems have been used in the clinical management of CAR T-cell recipients. The ASTCT grading system described by Lee et al 17 (Table 2) appears to be most suitable, and is gradually becoming the industry standard. Legacy grading systems are largely of historical interest but are still being used in some active clinical trials. These systems are compared in Appendix B. managed according to grade as described in Table 3, which is a harmonized summary of the management guidelines proposed by EBMT, ASCO, CARTOX groups and ZUMA-1 safety cohorts 4 and 6 16,18,19,20,21 .
Principles of CRS management include the following:
- The onset of CRS corresponds to the period of most rapid expansion of the CAR T-cell population.
During this time, high levels of cytokines are elaborated leading to the clinical manifestations of the syndrome. Importantly, IL6 levels correlate with the severity of CRS and the anti-IL6 receptor antibody tocilizumab has been shown to rapidly reverse the course of CRS.
- Hypotension that persists after 1-2 liters of 0.9% normal saline is unlikely to respond to further fluid resuscitation. The reasons for this are unclear but include the presence of vascular leak, vasoplegia and occult stress cardiomyopathy. Hypotension that fails to respond to two fluid challenges and tocilizumab should be treated with vasopressors.
- Although we recommend corticosteroids for patients with severe CRS, the use of these agents for reasons beyond the management of CRS, for instance as premedication prior to blood transfusion or for minor allergic symptoms, should be avoided.
- In general CRS that develops shortly (< 72 hours) after CAR T-cell infusion has a more aggressive course and requires more intensive treatment than that arising more gradually (72 hours after infusion). In addition, patients with comorbid medical conditions may experience a more complicated course with CRS and so early initiation of anticytokine therapy is justifiable in this population.
- In general the use of tocilizumab and steroids have moved earlier in the course of CRS treatment.
Recent evidence suggests that the use of tocilizumab and steroids do not impact important outcomes of CAR T-cell therapy such as progression-free and overall survival 19,20,22,23 . However, high-dose or prolonged corticosteroid use has been associated with poor outcomes in some studies 24 , hence corticosteroids should be rapidly tapered upon improvement and discontinued upon resolution of CRS.
- The results of ZUMA-1 safety cohort 6 showed that low-dose corticosteroid prophylaxis may reduce the risk of severe CRS and severe ICANS compared to historical controls 20 . However, interpretation of this study is limited by its small sample size, single-arm design, and baseline differences in tumor burden and inflammatory state.   The ICE tool is reproducible and prognostic, and has been integrated into a comprehensive ASTCT ICANS grading system (Table 4). ICANS management according to grade is outlined in Table 5. The mainstay of treatment is supportive care along with corticosteroids. Tociluzumab does not appear to have a significant role in the treatment of ICANS but can be considered if there is concurrent CRS. 2. We recommend the provision of 1 unit of red cells based on daily CBC demonstrating a hemoglobin <70g/L (15 mL/kg to a maximum of 1 unit for pediatrics). The use of a higher red cell transfusion threshold would be at the discretion of the clinician based on clinical judgement such as symptoms of anemia.
- We recommend the provision of 1 unit of pooled platelets based on daily CBC demonstrating platelets < 10 x 10 9 /L (10 mL/kg, maximum of 1 unit for pediatrics). The use of a higher platelet transfusion threshold would be at the discretion of the clinician based on clinical judgement such as active bleeding.
- We do NOT recommend the routine use of therapeutic platelet transfusions or prophylactic tranexamic acid instead of prophylactic platelets. It may be reasonable to consider their use in exceptional circumstances e.g., Jehovah's Witness.
- We do NOT recommend choosing blood products based on duration of storage.
- We recommend the routine use of G-CSF post-autologous HCT starting on Day 7 until ANC>0.5.
- We do NOT recommend the routine use of G-CSF post-allogeneic HCT (excepting nonmalignant pediatric disorders).
- We do NOT recommend the routine use of erythropoietin post-HCT. It may be reasonable to consider its use in exceptional circumstances e.g., Jehovah's Witness. 

# Background
High dose chemotherapy with or without radiation followed by hematopoietic stem cell (HSC) rescue, typically suppress the production of blood cells by the bone marrow for 7 to 14 days. This results in aplasia, during which the patient is likely to require prophylactic or therapeutic transfusions of red cells and platelets. This is particularly salient in the allogeneic setting where longer periods of transfusion support may be required, when recovery is complicated by delayed engraftment, acute graft-versus-host disease (GvHD) or severe sepsis.
There is a paucity of randomized controlled trial data to guide transfusion practice in the HCT setting 1 . Indeed, guidelines for transfusion support are often extended to the hematopoietic cell transplant (HCT) setting from general oncology/medicine despite the lack of strong clinical trial evidence (insert guidelines) 2-6 .

# Transfusion Utilization
It has been estimated that up to 39% of the total blood transfused in the USA in 2017 was used by inpatient medicine (including hematology/oncology) patients 7 , while an estimate of 27.1% in hematology/oncology was noted in the UK in 2014 8 . The frequency of transfusion support is the highest post-conditioning chemoradiotherapy and decreases significantly after the 1 st 30 days consistent with the timing of stem cell engraftment. For instance, Xenocostas et al. reported that the mean number of red cell units transfused per patient from 0 to 60 days was 6.8 +/-6.4; 61 to 120 days, 3.2 +/-5.5; and 121 to 180 days, 2.0 +/-4.6 9 . Factors that are associated with avoidance of transfusion after HCT include male sex (p = 0.0013), diagnosis, specifically plasma cell dyscrasias (p < 0.0001), early-stage disease (p = 0.006), and higher baseline hemoglobin (Hb) at time of transplant (p < 0.0001) 10 . The following  

# Association with post-HCT Outcomes
While confounded by indication, lower hemoglobin levels and/or transfusion support have been associated with various negative post-HCT outcomes. However, it remains unclear if such "risk factors" are modifiable and whether they would lead to improved post-HCT outcomes.
For instance, Xenoscosta et al. in a retrospective study of 519 consecutive patients receiving allogeneic HCT between January 1995 and March 2000 demonstrates an increased mortality during the 6-month period after HCT was associated with lower pre-HCT hemoglobin levels. Similar findings have been reported in the cord blood HCT setting where RBC transfusion >/=18 units by day 30 was significantly associated with higher overall mortality (hazard ratio, 1.86; P = 0.018) 11 . A more recent retrospective study by Hosoba et al. of 322 consecutive patients receiving an allogeneic bone marrow or granulocyte colony-stimulating factor-mobilized blood stem cell graft for a hematologic malignancy 12 . This study demonstrated that transfusion of more than the median number of RBC units (HR, 2.1; 95% CI, 1.1 to 3.7; P = .02) were independently associated with greater risk of grade III-IV acute GVHD in a multivariable analysis model and transfusion of more than the median number (5 units within 27 days) of RBC units (HR, 1.4; 95% CI, 1.0 to 2.0; P = .054) was associated with inferior overall survival. 

# Blood Products
The Alberta Bone Marrow and Blood Cell Transplant Program relies on the Canadian Blood Services for transfusion products. The collection, testing, processing, contents and distribution of these blood products will follow the Canadian Blood Services procedures 15 . Blood products are issued by Transfusion Medicine, Alberta Precision Laboratories.

# Red Cell Transfusion
Threshold: Different strategies have been developed for RBC transfusions. A restrictive transfusion strategy seeks to maintain a lower hemoglobin level (usually between 70 g/L to 90 g/L) with a trigger for transfusion when the hemoglobin drops below 70 g/L), whereas a liberal transfusion strategy aims to maintain a higher hemoglobin (usually between 100 g/L to 120 g/L, with a threshold for transfusion when hemoglobin drops below 100 g/L). There are very few randomized studies examining red cell transfusion thresholds in the oncology setting as summarized by a recent Cochrane review in 2017 16 .
The review suggests that a restrictive RBC transfusion policy has little or no effect on mortality at 30 to 100 days, bleeding, or hospital stay. However, there is absence of data on health-related quality of life, arterial or venous thromboembolic events, length of intensive care admission or readmission to hospital. .0004). After adjusting for transfusion type and baseline FACT-BMT score, the restrictive-strategy group had a higher FACT-BMT score at day 100 (difference of 1.6 points; 95% CI, 2.5 to 5.6 points), which was noninferior compared with that of the liberal-strategy group. Additionally, there were no significant differences in clinical outcomes between the transfusion strategies. Another Canadian Blood and Marrow Transplant Group trial compared red blood cell transfusion thresholds of 120 g/L in the experimental arm and 70 g/L in the control arm. The study was stopped early due to excess sinusoidal obstructive syndrome in the experimental group 18 .

# Number of Red Cell Units per Transfusion:
With the advent of the Choosing Wisely initiatives 19 , many clinicians are using one-unit transfusions as opposed to using two units at a time. Observational studies support this safe strategy with decreases in the use of red cell units  although the results are inconsistent 23 . Moreover, it remains unclear if a one-unit transfusion leads to better patient satisfaction or improved health care utilization beyond the number of units transfused.

# Duration of Storage of Red Cell Products:
Laboratory evidence coupled with early clinical observational studies suggest that there might be concerns of using older red cell products, i.e., storage lesion 24 . However, numerous randomized studies in a varied clinical setting, summarized by systematic reviews have found no convincing evidence that the age of red blood cells have an adverse effect on patient outcomes  . Moreover, retrospective reviews in the general cancer 30 and HCT 31 settings would further affirm this absence of association.

# Red Cell Transfusion-Summary:
Taken together, the clinical evidence supports the use of a restrictive red cell transfusion threshold in patients undergoing HCT. However, it is reasonable to consider an individualized higher red cell threshold depending on clinical judgement such as the presence of symptoms of anemia. There is no evidence to support preference for "younger" red cell units over "older" units. It is reasonable and practical to provide 1-unit red cell unit per transfusion.

# Platelet Transfusion
Thresholds: Clinically significant bleeding related to thrombocytopenia occurs in nearly 50% of all patients undergoing HCT. Over the last 2 decades, there have been randomized controlled trials examining platelet transfusion thresholds (where the primary endpoint is WHO grade 2 or higher bleeding), summarized by the following  The results from these studies have informed the care of patients with hematologic malignancies receiving high dose chemotherapy, where the current standard practice is to transfuse platelets prophylactically when the daily platelet count is < 10 x 10 9 /L to prevent bleeding 3,6, .

# Platelet Dose:
Additionally, there have been 5 RCTs evaluating the efficacy of different platelet doses  summarized by a Cochrane review 44 . For instance, the more recent and adequately powered study by Slichter et al. randomized (n=1,272) patients undergoing hematopoietic stem-cell transplantation or chemotherapy for hematologic cancers or solid tumors to receive prophylactic platelet transfusions at a low dose, a standard dose, or a high dose (1.110 11 , 2.210 11 , or 4.410 11 ) platelets per square meter of body-surface area, respectively 43 . They demonstrate that low doses of platelets administered as a prophylactic transfusion led to fewer platelets transfused per patient, but an increased number of www.ahs.ca/guru BMT Standard Practice Manual Last Revised: August 3, 2023 Effective: June 27, 2023 transfusions given. At doses between 1.110 11 and 4.410 11 platelets per square meter, the number of platelets in the prophylactic transfusion had no effect on the incidence of bleeding.
Taken together, there is no evidence to suggest that a low-dose platelet transfusion policy is associated with an increased bleeding risk compared to a standard-dose or high-dose policy, or that a high-dose platelet transfusion policy is associated with a decreased risk of bleeding when compared to a standard-dose policy 44 . However, a low-dose platelet transfusion strategy leads to an increased number of transfusion episodes compared to a standard-dose strategy. A high-dose platelet transfusion strategy does not decrease the number of transfusion episodes per participant compared to a standard-dose regimen, and it may increase the number of transfusion-related adverse events.

# Duration of Storage of Platelets:
Platelets are usually stored for up to 5 days prior to transfusion, although in some blood services the storage period is extended to 7 days. During storage, changes occur in both platelets and storage medium, which may lead to platelet activation and dysfunction. There have been several observational studies, mostly in the critical care setting that evaluated the potential impact of platelet storage and clinical outcomes. A recent systematic review of such studies suggests that storage time does not appear to be associated with clinical outcomes, including bleeding, sepsis or mortality 27 . However, the freshest PLTs (less than 3 days) were associated with a better CCI, although there was no impact on bleeding events. Taken together, the duration of storage of transfused platelets likely has no appreciable impact on post-HCT outcomes.

# Platelet Transfusion Alternatives:
However, the true benefit of prophylactic platelet transfusions in the autologous HCT setting is unclear; subgroup analyses from 2 recent studies suggest that a therapeutic strategy (transfusing platelets only to treat bleeding) may be as effective as a prophylactic transfusion strategy 45,46 . There has been interest in the use of prophylactic TXA to prevent bleeding in patients with chemotherapyrelated hypoproliferative thrombocytopenia 47,48 . Gernshiemer et al. in the a-TREAT Trial evaluated the effects of prophylactic TXA in addition to routine transfusion therapy on bleeding and transfusion requirements in a multicenter, double-blind placebo controlled randomized clinical trial in patients undergoing treatment for hematologic malignancy. 330 patients were activated and evaluable; 327 received at least one dose of study drug. The adjusted odds ratio of grade 2+ bleeding was 0.86 (95% CI: 0.52, 1.38; p-value=0.74). The difference in mean number of transfusions was 0.1 (95% CI: -1.9, 2.0; p-value=0.94), while the average difference in days alive without grade 2+ bleeding was 0.1 (95% CI: -1.4, 1.5; p-value=0.94). As such, the authors conclude that Prophylactic TXA has no effect on the incidence of WHO Grade 2+ bleeding when given in addition to routine plt transfusions to severely thrombocytopenic patients undergoing therapy for hematologic malignancy 114 .
Additionally, there are 2 ongoing RCTs, with another examining the addition of prophylactic TXA to prophylactic platelet transfusions in patients with in patients with hematological malignancies with severe thrombocytopenia 49 and another examining prophylactic tranexamic acid instead of prophylactic platelets in patients undergoing autologous HCT 118 .

# Platelet Transfusion-Summary:
Taken together, the clinical evidence supports the use of < 10 x 10 9 /L as a platelet transfusion threshold. However, it is reasonable to consider an individualized higher platelet threshold and/or dose, depending on clinical judgement such as the presence of persistent bleeding. There is a paucity of high-quality evidence to routinely use therapeutic over prophylactic platelet transfusions. There is no evidence to support preference for "younger" platelet units over "older" units.

# Platelet Refractoriness:
Platelet transfusion refractoriness is defined as the repeated failure to achieve satisfactory responses to platelet transfusions from random donor 51 . There have been various formulae that have been proposed to determine platelet refractoriness 52 . However, it is argued that such calculations are not clinically useful. Instead, a pragmatic definition of failure of the immediate post-transfusion (10 to 60 minutes) platelet increment to exceed the transfusion trigger or a rise of less than 1010 9 /L 20 to 24 hours after transfusion with unsatisfactory responses to two or more transfusions 53 . The following table summarizes some potential causes for platelet refractoriness: The following are additional considerations:
- It is reasonable to provide both prophylactic standard daily prophylactic non-HLA matched platelets and tranexamic acid measures in the absence of a satisfactory response with HLA matched platelets or if HLA matched platelets are not available. 2. In cases where the risk of bleeding is deemed low, it is reasonable to solely provide prophylactic tranexamic acid. 3. There are advocates for platelet cross-matching, but it is not routinely available in Canada and not recommended over HLA matched platelets. 4. Intravenous immunoglobulin is not effective in the management of platelet refractoriness.

# Prevention of Transfusion-Associated GVHD
While recipient anti-donor responses are usually able to eliminate donor leukocytes, settings in which the recipient anti-donor responses are impaired permits unabated donor anti-recipient responses (which can occur in the HCT setting), resulting in transfusion-associated graft-versus-host disease (TA-GVHD) 55 . There are 2 standard complimentary approaches to reduce the risk of TA-GVHD: 1) Leukoreduction, and 2) Irradiation of the blood product.
The ability to deplete leukocytes from the blood product reduces the incidence of TA-GVHD 56,57 . Blood products from the Canadian Blood Services are universally leukodepleted, a practice that is supported by randomized trial data 54,58,59 . However, leukodepletion may not be fully protective 60 . The results of in vitro studies led to the adoption of a dose of 25-30 Gy -irradiation as a standard for the inactivation of T lymphocytes in blood products 61,62 . This led to routine irradiation of blood products, especially in settings in where patients are at risk for developing TA-GVHD. Reports from Japan (population at higher risk of TA-GVHD) indicate that no further cases of TA-GVHD were detected once universal irradiation was implemented 63,64 .
It should be kept in mind that prolonged storage of pre-irradiated red blood cells has been associated with high potassium levels, in vitro hemolysis and decreased post-transfusion recovery 65 . Irradiation of red blood cell products should occur as near as possible to the time of transfusion, and no longer than 14 days prior to transfusion. This is particularly important in infants, where life threatening hyperkalemia can occur following transfusion of irradiated RBC. In patients at risk of hyperkalemia, it is recommended red cells be transfused within 24 hours of irradiation. If freshly irradiated RBC are not available, the product should undergo centrifugation and supernatant plasma removal prior to transfusion.
There are other laboratory techniques such as psoralen/UVA light treatment (primary purpose of pathogen reduction) that can inactivate T cells in blood products and potentially reduce the risk of transfusion-associated graft-versus-host disease (TA-GVHD), but this has not been routinely adopted by Canadian Blood Services. Importantly, pathogen reduced platelets increase the risk of platelet refractoriness and the platelet transfusion requirement 66 

# Prevention of CMV Transmission
Cytomegalovirus (CMV) infection continues to be a serious complication following HSCT 67,68 . Most CMV infections may be due to a reactivation of the virus from a previous infection rather than due to the acquisition of a new strain 69 . However, CMV antibody-negative persons are at risk for developing a transfusion-transmitted de novo CMV infection. There are 2 standard complimentary approaches to reduce this risk: 1) Use of CMV-antibody negative blood, and 2) leukoreduced components.
As discussed, blood products from the Canadian Blood Services undergo universal leukoreduction. This practice is further supported by studies demonstrating that leukoreduced components are as effective as antibody-negative components in the prevention of transfusion-transmitted CMV infection  . However, early consensus guidelines supported the use of both leukoreduction and provision of CMV-antibody negative blood in at risk population (belt and suspenders approach) 74,75 . However, this practice has been challenged 71,76 . For instance, a single Canadian HCT institution before-after study reviewed 186 patients who were CMV negative and received an allogeneic HCT from a CMV-negative donor between October 1, 1999 and June 30, 2012 77 . Of these, 89 patients received an HCT before January 2007, during the time when patients received leukoreduced and CMV-negative blood products. Seventy-seven patients received an HCT after this time, receiving only leukoreduced blood products. CMV viremia was detected in 3 patients who received CMV-negative leukoreduced blood products (3.37%) and in 1 patient who received only leukoreduced blood products (1.30%, P = .6244). Of the patients who developed CMV viremia, 2 developed suspected CMV disease. Both of these patients were transfused with CMV-negative blood products. This suggests that in the era of universal leukoreduction of blood products, that testing for CMVnegative blood products is not needed for HCT recipients. Indeed, the Canadian National Advisory Committee on Blood and Blood Products (NAC) subcommittee has deemed that CMV-safe leukoreduced cellular blood products are equivalent in safety to CMV-seronegative and leukoreduced blood products for transfusion in all patient populations except for intrauterine transfusion.

# Transfusion in ABO-or RhD-Incompatible HCT
Please refer to Chapter entitled ABO Incompatible Graft and Recipient in the Alberta Bone Marrow and Blood Cell Transplant Program: BMT Standard Practice Manual.

# Growth Factor Support

# Granulocyte colony-stimulating factor:
The use of G-CSFs post-HCT is supported by decreased time to engraftment ranging between 1-6 days, with some studies demonstrating savings in duration of hospitalization, infections and survival 78 . The timing of administration of G-CSF has been the subject of investigation -early or delayed approaches. Such studies have not demonstrated any clear disadvantage of delaying G-CSF for up to 10 days post-HCT in the autologous setting   but there is theoretical concern that T cell reconstitution may be impaired by G-CSF, and GVHD may be induced or worsen with its use. Although G-CSF is often administered post-HCT to accelerate neutrophil recovery, there appears to be no long-term benefit or disadvantage of giving G-CSF after HCT to promote hematopoietic recovery 93 .
Taken together, it is reasonable to provide routine post-autologous HCT G-CSF starting on Day 7 (until ANC >0.5) to accelerate neutrophil recovery which in principle may improve infectious complications and assist with earlier hospital discharge. We do not recommend the routine use of G-CSF in the allogeneic setting. This recommendation does not apply to most pediatric non-malignant conditions.

# Erythropoiesis-stimulating agents:
The use of erythropoiesis-stimulating agents to manage anemia raises hemoglobin levels, reduces the need for RBC transfusions, but increases the risk of thromboembolic events 94 . In the setting of HCT, there have been 6 randomized studies addressing the utility of erythropoietin. The most recent study, which might inform current practice, was conducted by Jaspers et. al in 2014 95 . The authors randomized 131 patients between no treatment (control arm) or erythropoietin at 500 U/kg per week. They demonstrate that erythropoietin results in a higher proportion (63.1%) of hemoglobin 13 g/dL before Day 126 as compared with 8.1% in the control arm. Additionally, Hb levels were higher and transfusion requirements decreased in the erythropoietin arm. There was no difference in rates of thromboembolic events or other complications between the 2 arms. There was no impact on long term survival 96 .  Taken together, the use of erythropoietin post-HCT can improve hemoglobin levels and assist with red cell utilization. However, the absence of quality of life data from the available trials tempers its use. Moreover, enthusiasm for the use of erythropoietin in the HCT setting has waned, especially with the recognition of serious adverse events in several patient populations 97,98 .

# Thrombopoietin receptor agonists:
Prolonged thrombocytopenia after HCT is a strong risk factor for transplantation-related mortality, and efforts to improve platelets may lead to improve post-HCT outcomes and decrease platelet utilization 99,100 . The literature categorizes these patients into 2 types-prolonged isolated thrombocytopenia (PIT) and secondary failure of platelet recovery (SFPR)-according to the timeline of presentation.
Prolonged isolated thrombocytopenia (PIT) can be attributed to: g/dL for at least 3 consecutive days by 28 days after HSCT, with transfusion dependence associated with hypoplastic-aplastic bone marrow and complete donor chimerism without concurrent GVHD or disease relapse.
Secondary failure of platelet recovery (SFPR) refers to thrombocytopenia that develops after initial platelet engraftment and is not due to graft rejection or relapse. SFPR is defined as a decline in platelet count of <20  10 9 /L for 7 consecutive days or requiring transfusion support after achieving a sustained platelet count 50  10 9 /L without transfusion for 7 consecutive days after HCT 101 .
Thrombopoietin receptor agonists (TPOs) are novel treatments for patients with chronic ITP aimed at increasing platelet production through interactions with the TPO receptor on megakaryocytes 102 . Beyond potential improvements in platelet counts, there is laboratory and clinical evidence to support the use of TPO to overcome depletion of HSCs and progenitor cells in aplastic anemia 103 . Invariably, these observations and experiences have led to the use of TPOs in patients with either persistent thrombocytopenia or general hypoplasia post-HCT 104,105 .
A recent systematic review comprising of 25 reports (case series and reports) suggests that patients with prolonged post-HCT thrombocytopenia may respond to both eltrombopag (overall response rate , 70%) and romiplostim (ORR, 82%), with no evidence of serious adverse effects 106 . The authors note that most of the studies reported initiating treatment at a lower dosage range and escalating the dosage based on the response to treatment. Patients were treated for variable durations, ranging from 2 weeks to 1 year, depending on the severity of thrombocytopenia and the response to treatment.   100.4 o F in the midst of chemotherapy-induced grade 4 neutropenia received a first course of IV antibiotics in hospital. Taken from National Cancer Institute Common terminology Criteria for Adverse Events (NCI CTCAE, version 3.0). LLN, lower limit of normal.

# Prediction of Cytopenias after CAR-T
Rejeski et al. created the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (eg, platelet count, hemoglobin, and ANC) and baseline inflammation (eg, Creactive protein and ferritin) 115 . A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs 5.5 days; P < .001) and a higher incidence of severe thrombocytopenia (87% vs 34%; P < .001) and anemia (96% vs 40%; P < .001). Additionally, high CAR-HEMATOTOX score patients more frequently developed severe infections (40% vs 8%, p<0.0001)-particularly severe bacterial infections (27% vs 0.9%, p<0.0001). Further, they experienced worse median progressionfree (3.4 vs 12.6 months) and overall survival (9.1 months vs not-reached), and were hospitalized longer (median 20 vs 16 days) 116 . When psychosocial factors severely impair functioning and/or adherence to treatment plan, or place the patient at immediate safety risk (e.g., actively psychotic, suicidal, substance dependent, extreme poverty, high degree of family conflict), HSCT may be deferred in order to prioritize stabilization of psychosocial concerns. 6. The ultimate decision to proceed to HCT is an interdisciplinary team-based decision paying attention to recipient characteristics and their perceived "trade-offs" with disease and donor characteristics. 7. Eligibility for chimeric antigen receptor T-cell therapy (CAR-T) will follow the same principals for assessment as in standard HCT.  The relative contributions of these characteristics (potentially overlapping) to HCT success is not and unlikely to be clearly defined. In part, evaluations of individual characteristics within observational studies variably consider other pertinent characteristics. Moreover, secular trends in HCT technology and supportive care would suggest the relative contributions would be "fluid". The ultimate decision to proceed to HCT is an interdisciplinary team-based decision paying attention to these characteristics and their perceived "trade-offs".
While it is important to acknowledge that patient characteristics are associated with post-HCT outcomes, there is no clear and/or consistent evidence that modification of these characteristics clearly attenuates post-HCT outcomes -modifiable risk factor(s). This review focuses on Patient characteristics and draws attention to assessments and variables that might influence the decision to proceed with HCT.

# Physical Assessment(s)
A detailed history, physical examination complemented with investigative diagnostics is a crucial 1 st step in documenting and assessing comorbidities  . The rationale is presented in the following sections:

# Age
An ideal HCT candidate should be in excellent physical and physiologic health at the time of HCT.
There is a movement to consider physiologic age over chronologic age in the determination of HCT eligibility. However, the chronologic age could be considered a simple variable that embraces a multitude of patient characteristics.
In the autologous setting, data on the impact of age on outcomes post HCT is predominantly in myeloma setting. Data from randomized controlled trials would support autologous HCT up to a biologic age of 65 years. In contrast, there is no randomized controlled trial data sup-porting autologous HCT in patients aged >65 years with multiple myeloma. However, there are indeed observational studies that suggest that autologous HCT can be safely performed in older patients in myeloma  . There are fewer studies examining its impact in the lymphoma setting  . The paucity of data would suggest that biologic age should not be sole criteria used to determine eligibility for Last Revised: August 24, 2021 Effective: August 24, 2021 autologous HCT. Rather, one may need to consider attenuating the dosing of the conditioning regimen to compensate for age among other factors as discussed.
In the allogeneic setting, CIBMTR registry data suggests that the median age of HCT has increased to up to 75 years over the last few decades 12 . Indeed, a retrospective study from EBMT suggests that there is no significant association between age and relapse or non-relapse mortality in a cohort of 1333 patients (age 50-74 years) 13 . Further, a similar analysis from CIBMTR in 1080 patients (>40 years) receiving a reduced intensity conditioning found that chronologic age did not impact rates of non-relapse mortality, relapse or GVHD 14 . Finally, a review of 372 patients aged 60-75 enrolled in prospective clinical trials of a reduced intensity conditioning determined that age did not appear to influence GVHD, PFS or OS but older individuals had increased bacterial infections and hospitalization 15 .
Given potential and inherent biases in the assessment of physiologic age, there is increasing interest in utilizing biomarkers of physiologic age 16 . Indeed, there are numerous candidate markers including: p16 INK4A , Leukocyte telomere length, DNA methylation, miRNA, Immunosenescence, SASP, Anemia, IL-6, CRP, NT-proBNP, Albumin, D-dimer, TNF and sICAM-1. Further, various geriatric assessment scales have also been used 17,18 . Among these, it appears that p16 INK4A may be a leading biomarker candidate -a molecular maker of cellular senescence  .
Observational health outcomes research evaluating age is inherently confounded by indication that might suggest a more conservative approach in utilizing age in determining HCT eligibility. Taken together, it is reasonable to consider using a cautious and extensive evaluation for older (e.g. >65years) or frailer patients.

# Performance Status
With respect to performance status assessment, we prefer the Karnofsky Performance Score (KPS) score over Eastern Cooperative Oncology Group (ECOG) score as it allows a more "granular" range to base one's assessment. Moreover, the assessment of performance status is subjective and a wider scoring range may improve the quality of the assessment. Given concerns that performance status is clinician assigned with overestimation 22 , a geriatric assessment (GA) has its proponents in older patients 23,24 . See section on Geriatric assessments.
We suggest that it is reasonable to proceed with HCT if the KPS score >60 and consider utilizing CGA in individuals who are >65 years of age to better guide decision making. In those with a KPS of <60, a more extensive evaluation would be warranted. Further, we suggest that HCT be not offered in the presence of a HCT-CI score of 3 and one abnormal ADL. 

# Pulmonary Evaluation
Post-HCT pulmonary complications such as therapy related lung toxicity, pulmonary GVHD and its variants, TRALI and infectious complications can occur. Pre-existing lung disease as measured by pulmonary function tests (PFTs) can increase the risk and morbidity of post-HCT pulmonary complications with up to 3% and 24% of autologous and allogeneic HCT patients developing severe pulmonary complications requiring mechanical ventilation 25 . Indeed, an abnormal PFT pre-HCT is associated with poorer post-transplant outcomes  . Further, smoking pre-HCT is independently associated with poor outcomes 30 .
The proposed cutoff for eligibility in HCT in clinical trials is typically a corrected DLCO >50% although a true cutoff is unknown. This cutoff which may be dependent on the planned conditioning chemotherapy 31 . In the allogeneic setting, a higher threshold of DLCO>60% has been used. Moreover, the PAM score (described later) uses a DLCO cutoff of 60% 32 . The correlation between FEV1 and DLCO pre-HCT is poor, with pre-HCT FEV1 independently predictive of early respiratory failure 33,34 .
Taken together, it is optimal to consider HCT in an individual with a DLCO >60% and a FEV1>60%. In all other scenarios, the case should be discussed at an individual basis.

# Cardiac Evaluation
In general, individuals with poor cardiac reserve with a LVEF <40%, uncontrolled arrhythmia or coronary artery should not proceed with HCT 35 . Overall, the rate of major or life threatening cardiac events post-HCT has been estimated to be <1% 36 .
Cardiac injury can occur post-HCT, and it is assumed to be more serious in individuals with less cardiac reserve. A higher LVEF threshold maybe warranted when cardiotoxic conditioning (e.g., cyclophosphamide or TBI) is contemplated. However, it may be reasonable to accept a LVEF of >45% in most circumstances 37,38 . Separately, there is also an association between prolonged QT and QT dispersion noted on routine EKG with post-HCT morbidity from heart failure 39,40 . Further, it would be important to optimize cardiac risk factors prior to HCT 41 .
Taken together, it is optimal to consider HCT in an individual with a LVEF>45% with a normal EKG. In all other scenarios, the case should be discussed at an individual basis.

# Hepatic Evaluation
Baseline elevations of serum transaminases and alkaline phosphatase are associated with an increased risk of sinusoidal obstruction syndrome (SOS) post-HCT in the allogeneic setting 42 . Serum hyperferritinemia is also associated with increased risk of SOS, disease free and overall survival  . Given these associations, it may be reasonable to consider chelation therapy for iron www.ahs.ca/guru BMT Standard Practice Manual Last Revised: August 24, 2021 Effective: August 24, 2021 autologous HCT setting for myeloma, where impairments in geriatric domains are common even among those considered to have a good performance states 108 and can identify patients who are at a greater risk for morbidity 109 . Such studies suggest and emphasize that CGA is strongly associated with post-HCT outcomes and has a higher HR, even when other traditional patient and disease variables are factored in.
The concepts that encompass frailty has been recently summarized by an excellent review article 110 . The authors suggest that the historic use of chronologic age, comorbidities and performance may be too simplistic to capture a full sense of vitality. They and others have suggest that the regular incorporation of frailty measurements such as CGA may be useful in evaluating fitness for HCT 111 .

# Patient Eligibility for chimeric antigen receptor T-cell therapy (CAR-T)
The eligibility for CAR-T cells will be predominantly assessed on disease based factors (see appropriate chapters for discussion). The principals as described in the preceding paragraphs for standard allogeneic and autologous HCT would apply. Recognizing there is a paucity of evidence, there is a sense that lower thresholds for eligibility from the perspective of patient factors may apply given that there is no high-dose therapy.
There are areas of uncertainty on whether a history of malignancy, allogeneic HCT, prior treatment with BiTE antibodies or CNS involvement represented an exclusion criteria 112 . The following table is summarizes the eligibility criteria from large RCTs and the recommendations from EBMT/JACIE 113  recommend proceeding with allogeneic HCT. In six vignettes, at least 64% indicated do not proceed: suicidal ideation (86.8%) uses addictive illicit drugs (81.7%), history of noncompliance (80.5%), no lay caregiver (69.3%), alcoholic (64.8%), and mild dementia/Alzheimer's (64.4%). In 10 vignettes, at least 73% indicated proceed. On four vignettes, professional subgroups differed in their recommendation on whether or not to proceed with allogeneic BMT 115 .
Interestingly, a follow-up survey of 62 chairpersons of the hospital ethics committees (HEC) with an accredited HCT program elicited whether they would recommend HCT in the 6 scenarios (as above) where the majority HCT clinicians would not. Opinions regarding transplant differed in one case only, in a patient with mild dementia; 27% of HEC chairpersons recommended not proceeding with BMT, which was significantly lower than that of nurses (68%, P<0.001), physicians (63.5%, P<0.001) and social workers (51.9%, P=0.05) 116 .

# Psychosocial pre-HSCT Assessment Tools
Although a Gestalt approach to assessment is feasible, a formal validated tool is preferred. Indeed, there are numerous general screening tools including distress screening tools  , but may not be specific to the HCT population.
Garcia et al. developed a psychosocial structured interview to assess candidates for HCT with the interview averaging 50 minutes to complete 120 . In the absence of a comprehensive and validated tool, we suggest using this structured interview tool to ensure consistent history taking. The elements garnered from this structured inter-view could potentially be utilized to subsequently populate other scales and questionnaires.

# Psychosocial assessment of candidates for transplantation (PACT)
This scale captures information in four domains (social support, psychological health, lifestyle factors, and patients understanding of the transplant process) with eight subscales, each rated on a 5-point scale 121 . This scale was originally developed for clinical decision-making in psychosocial screening of organ transplant (heart and liver) candidates 122  . There was no association between final PACT rating and neutrophil or platelet engraftment, acute or chronic GVHD, or relapse 123 . In contrast, data from Japan suggests that lower PACT scores in the domain of compliance with medications and medical advice were significantly associated with poorer OS (HR = 1.75, P = 0.03) 124 .

# Patient Health Questionnaire (PHQ)
In a small randomized study 125 , the Patient Health Questionnaire (PHQ) was used to assess for depressive disorders, anxiety, substance abuse, and problems in occupational or interpersonal functioning (functional disruption) and was provided to patients before meeting with their medical provider (n = 50; experimental group) or afterwards (n = 51; control group). The prevalence of Last Revised: August 24, 2021 Effective: August 24, 2021 clinically significant depression (21%), anxiety (14%), or suicidal ideation (8%) did not differ between the 2 groups. Patients in the experimental group were likely to have discussion of psychological symptoms than the control group (68% versus 49%, P = .05). Medical providers were significantly more satisfied with the management of psychological issues for the experimental group (P < .001).
Patients with depression or anxiety were significantly more likely to prefer the PHQ be used at future visits (P = .02 and P = .001, respectively).

# The Transplant Evaluation Rating Scale (TERS)
The TERS score is a compilation of scores on 10 weighted factors: psychiatric history of Axis I disorder, psychiatric history of Axis II disorder, substance abuse, health behaviors, compliance, quality of family/social support, history of coping, coping with disease and treatment, quality of affect, and mental status. The TERS was prospectively used at a single institution 126 ; where patients in the high-risk TERS group had significantly longer hospital stays during the first 180 days and 1 year post-allogeneic HSCT compared with the low-risk group (16 vs 13 and 21 vs 16 days; P = .05 and .02, respectively). In their multivariable analysis, intermediate-and high-risk TERS scores predicted for inferior OS, similar DFS, and higher NRM compared with low-risk TERS score. In a subset analysis of patients with low/intermediate risk per Disease Risk Index, multivariable analysis showed that high-and intermediate-risk TERS scores predicted for significantly worse OS, worse DFS, higher NRM, and similar relapse rates compared with low-risk TERS score. Additionally, poor TERS scores have also been associated with higher readmission rates 109 .

# Distress
Distress is a complex term that is utilized to embrace multiple aspects mental health states. This broad concept has been evaluated in the context of HCT using different scales (validated and unvalidated). Consequently, it is challenging to given firm conclusions on its association with post-HCT outcomes.
Cancer and treatment specific distress pre-allogeneic HCT is associated with Post-traumatic Stress Disorder (PTSD). Specifically, uncertainty, appearance and sexuality as well as health burden were concepts associated with PTSD 127 . It has been estimated that PTSD occurs in 3.3% of HCT recipients; interestingly PTSD in HCT recipient caregivers is estimated at 6.6% (p=0.02) 128 . Pre-HCT psychological distress as measured with an unvalidated Likert-like scale was unrelated to survival in a single centered study 129 .
Taken together, the presence of pre-transplant patient distress may have psychologic consequences post-transplant, but does not clearly influence survival. Moreover, the management of distress of peri-HCT is not well-defined with a recent systematic review suggesting psychological interventions (cognitive behavioral or emotional processing methods) may provide some benefit in alleviating distress in HCT but conclusions remain tentative in light of methodological limitations and risk of bias in their included studies 130 . Interestingly, a recent RCT randomly assigning 160 patients undergoing HCT to receive inpatient palliative care integrated with transplant care (n = 81) or transplant care alone (n=79) suggest that intervention participants reported lower depression symptoms, lower PTSD symptoms but no difference in HRQOL or anxiety 131 . The intervention was composed of a palliative care clinician reviewing care at least twice a week broadly addressing topics of nausea, pain and mucositis, fatigue, insomnia, bowel problems, and psychological distress.

# Anxiety and Depression
A recent prospective observational study in six German allogeneic HCT centers evaluated the prevalence of depression and anxiety using the Hospital Anxiety and Depression Scale (HADS), comparing it to gender-matched controls (reference). They demonstrate that the rates of HADSdefined depression increased from 12% before HCT to up to 30% at 5 years after HCT, while anxiety was highest before HCT and settles to control baseline after HCT.
Pre-HCT clinical depression is associated with lower overall survival and higher acute GVHD among allogeneic transplant recipients 132 . Further, it is associated with fewer days alive and out of hospital within the 1 st 100 days after autologous and allogeneic setting. This could suggest routine screening for depression and providing pre-emptive pharmacologic and/or psychologic therapies to mitigate this risk factor.

# Non-Compliance
Compliance has been defined as the extent to which a person's behavior (in terms of medication, following diets, or executing lifestyle changes) coincides with medical or health advice 133 . The prevalence on non-compliance is unknown in the HCT population 134 . Rate of adherence to oral medications ranged from 33% to 94.7% 135,136 where it has been associated with increased risk of infections in the pediatric HCT setting 137 . Overall, there is a paucity of research that evaluates the consequences of noncompliance in adult HCT patients, nor the predictive value of pre-transplant compliance in determining post-transplant behavior. Further, the impact of compliance on therapeutic outcomes and the interventions that effectively increase compliance are all unknown.
Mumby et al. in a study of 151 autologous HCT patients suggests 80% of patients were deemed noncompliant with an aspect of the transplant on 1 day 138 . Non-compliance was defined as refusal of oral hygiene, prescribed exercise programs, oral nutrition and/or prescribed medications. In a multivariate analysis, the predictors of non-compliance in their cohort of patients were 1) gendermen, 2) presence of depression, 3) global distress and 4) nausea and vomiting severity. Interestingly, a small and older study of 92 HCT patients did not identify compliance as predictive of post-HCT outcomes 139 .
More recently, a single centre study from Japan retrospectively assigning the PACT scale to 119 HCT recipients demonstrate that lower PACT scores in the domain of compliance with medications and medical advice were significantly associated with poorer OS (HR = 1.75, P = 0.03) 124 .Similarly, the Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) scale was able to predict nonadherence defined as at least 1 life-threatening nonadherence event in the first 6 months posttransplant 140 .
It has been suggested that the following considerations may improve compliance 134 : 1) Provision of clear and consistent information with specific information on why consistent compliance is beneficial, 2) simplify treatment, 3) prioritize environmental precautions and health behaviors, 4) suggest ways to assist with forgetfulness, and 5) tailor the regimen as much as possible to the lifestyle of the patient.
Due to the paucity of data, non-compliance should not be an absolute contraindication to HCT.

# Substance Abuse
Lifetime substance abuse appears to be associated with adverse outcomes post-HCT 141 . In a single center case -control study, Chang et al. identified 17 individuals with lifetime substance abuse where with alcohol (71%), marijuana (30%), and opiates (30%) were identified as the principal substances of abuse. They identified controls, matching for disease and stage, type of transplant, pre-HCT conditioning regimen, and age. Survival analysis demonstrated reduced survival times for patients with substance abuse (p = .0022) 142 with 15 of 17 patients dying within the first year. Interestingly, a follow-up study did show this association 143 . Graf et al. suggest that a history of alcohol use disorder was associated with nonrelapse mortality (HR 2.17; p=0.004) in an analysis of 754 patients undergoing autologous HCT for lymphoma at a single centre 144 .
Due to the paucity of data, substance abuse should not be an absolute contraindication to HCT.

# Other Psychological Functioning and Coping Styles
Data on aspects of psychological functioning/coping style is sparse. However, a recent study evaluating 332 recipients of HCT using measures of illness perceptions (beliefs about cancer consequences and course, personal and treatment control over cancer, and understanding of one's cancer) suggest that greater personal and treatment control was associated with a healthier diet and reported greater well-being. Further, a better understanding of their cancer also was associated with a healthier diet, less depression, less anxiety, and greater well-being 145 . In addition, greater personal resilience (composite variable of self-esteem, mastery, and optimism) may promote better psychologic adjustment via improvements in depressive symptoms with decreased use of maladaptive meaning-making (searching for a reason for one's illness) was associated with less PTSD symptoms 146 . Similar findings were noted by Barata 

# Financial/Socioeconomic Status
The socioeconomic status (SES) of the recipient is associated with poor HCT outcomes due to multiple interrelated factors 148,149 . Specifically, lower attained education was associated with increased distress (P = .002), lower income was related to worse physical functioning (P = .005) and increased distress (P = .008), lack of employment before transplantation was associated with worse physical functioning (P < .01) 150 .
Further, low SES is also associated with higher risks of all-cause mortality (hazard ratio (HR) 1.98, P=0.012) and non-relapse mortality (NRM) (HR 2.22, P=0.028), but similar risks of relapse mortality (HR 1.01, P=0.97) compared with high SES patients. A trend toward better survival and lower NRM for high SES patients with no chronic GVHD was observed; low SES patients without GVHD had similar survival as patients with chronic GVHD 151 . Similar results were noted by Silla et al 152 . In contrast, Hamilton et al. suggest that SES was not associated with chronic GVHD outcomes 153 . Interestingly, Knight et al. suggests that low SES effects are modulated through upregulation of conserved transcriptional response to adversity (CTRA) 154 . From a psychologic perspective, it has been suggested that the effects of "objective" SES is modulated through the individual's "subjective" SES 155 .
The influence of SES is less clear in the autologous setting 156,157 and it is likely that other patient and/or disease factors are more important in this setting.

# Caregiver Considerations
There is an increasing reliance on caregivers as HCT programs shift towards an outpatient setting. In general, outpatient HCT are performed when there is a consistent caregiver. This invariably shifts the burden of care on to the caregiver. Indeed, caregivers are emotionally vulnerable than patients before HCT where cancer-related distress was the strongest correlate of anxiety and depression in both patients and caregivers 158 . Acknowledging, understanding and supporting the caregiving role would be prudent from the perspective of the HCT program.
The consistent presence of a caregiver is independently associated with superior post-allogeneic HCT overall survival 121,139,159 . The optimal caregiver(s) and the qualities of the caregiver remains unclear, however there is evidence to suggest the quality of the caregiver may matter more than caregiver consistent presence 160 . Caregivers commonly report elevated distress pre-HCT and both patient and caregiver distress was associated with patient HRQOL, with patients' physical well-being a significant contributor to caregiver well-being 161 . Interestingly, patient's perception of over-benefiting within a dyadic relationship was associated with patient distress, but not the patient's self-perceived burden 162 . Separately, there is evidence to suggest that unmarried status is associated with worse sleep in the allogeneic setting 150 .Overall, there is a paucity of evidence to guide practice as summarized by a systematic review 163 

# Summary

# Autologous Stem Cell Collections
- For autologous stem cell collection, mobilization options include growth factors alone (for patients who have not had prior chemo-or radio-therapy) or combined chemotherapy and growth factor mobilization (for those who have had prior chemo-or radio-therapy).
- Filgrastim is the pharmaceutical analog of G-CSF used for stem cell mobilization. Biosimilars may be used for autologous stem cell collection.
- Plerixafor is indicated for patients who are at risk for poor mobilization, those who have failed a previous mobilization attempt, and for salvage during a suboptimal mobilization attempt.
- Peripheral blood is the recommended source of stem cells for autologous transplantation. Bone marrow harvests are not recommended.
- Ex-vivo purging of autologous stem cell products is not recommended.
- For CD34 enriched products, CD34 collection targets will be set at 8 x 10 6 /kg and collected in a single full day apheresis. Plerixafor may be required if a sufficient peripheral blood CD34 count is not achieved with GCSF alone.

# Allogeneic Stem Cell Collections
- Allogeneic donors undergoing mobilization will receive G-CSF daily for five days. Additional dose(s) should be given on day 5 and/or day 6 if fewer than 3 x 10 6 CD34+ cells/kg are collected and a second day of collection should be arranged.
- Neupogen is the only brand of filgrastim approved by the World Marrow Donor Association (WMDA) for use in allogeneic donors; biosimilars are not to be used at this time.
- Related allogeneic donors who mobilize poorly with G-CSF alone (blood CD34 count 5-10 per microliter) will be offered off-label plerixafor. Those refusing plerixafor will undergo surgical bone marrow harvest on day +6 of G-CSF. Those who fail mobilization (CD34 count < 5) will undergo surgical marrow harvest on day +6.
- The Canadian Blood Services Stem Cell Donor Registry has indicated that plerixafor should not be given to unrelated donors who fail to mobilize with G-CSF. In the case of unrelated donors who are not mobilizing as expected, early communication to OneMatch is essential. The transplant center should be contacted in order to confirm that bone marrow would be acceptable prior to arranging a bone marrow harvest in these cases.
Autologous Stem Cell Mobilization Options.
The preferred stem cell source for autologous SCT is mobilized peripheral blood stem cells collected by apheresis. This is based upon small RCTs that demonstrated improved quality of life, shorter engraftment times, decreased blood and platelet transfusions, decreased hospital stays, and reduced 

# Summary
- Chimerism of blood T cells (CD3+) and blood malignancy lineage cells (eg, CD13/33+ cells in case of myeloid leukemia or CD19+ cells in case of B cell malignancy) is routinely determined in all allotransplant recipients at 3 months. This is to document engraftment, to assess risk for relapse, and to generate baseline values for potential later chimerism testing (when rejection or relapse is suspected). Results are interpreted as shown in Table 2. No anti-relapse therapy should be given based on only the chimerism result, as the chimerism has limited positive and negative predictive values for relapse. - Chimerism of marrow cells enriched for malignancy lineage/phenotype cells is useful for distinguishing relapse from increased percentage of marrow blasts due to "regeneration". This should be ordered by a hematopathologist.

# Techniques for Chimerism Determination
Chimerism (% cells of donor versus recipient origin) 1 can be determined using one of the techniques described in the table below (courtesy of F. Khan). The reasons are the very high quantitation accuracy, which facilitates comparison of current result to previous result(s), high informativeness (which means that chimerism can be reliably determined in >99% donor-recipient pairs), acceptable sensitivity (no data exist suggesting that sensitivity below 1-5% is clinically valuable), and applicability to all donor-recipient pairs (irrespective of sex matching).
The principle of the assay is explained using the following example: in a short tandem repeat segment of genome, the donor has 3 tetranucleotide repeats (GCTG GCTG GCTG) on both paternal and maternal chromosomes whereas the recipient has 4 tetranucleotide repeats (GCTG GCTG GCTG GCTG) on both paternal and maternal chromosomes (simple scenario, as in reality most persons are heterozygous). In a post-transplant patient specimen, the segment of genome is amplified by PCR, using primers for conserved sequences flanking the segment. The PCR product is subjected to electrophoresis, which separates the 3 tetranucleotide repeat amplicons from the 4 tetranucleotide repeat amplicons (the former amplicons move faster). As the amplicons are fluorescent dye-labeled, the ratio of donor to recipient chimerism is determined as the ratio of fluorescence of the donor (3 repeat) amplicons to the fluorescence of the recipient (4 repeat) amplicons.

# Clinical Utility
Chimerism of blood cells can be used for:

# Diagnosis of graft rejection
- Rejection is defined as <5% donor cells among T cells and myeloid cells in the absence of relapse.

# Risk assessment for relapse
- In Alberta, we routinely determine chimerism of sorted blood malignancy lineage cells and T cells at 3 months post-transplant (baseline). Subsequent chimerism determination can be done when/if rejection or relapse is suspected. Low % donor cells is only a risk factor for relapse, it is not diagnostic of relapse. Per preliminary analysis of patients undergoing first allo-HCT in Alberta between 2010 and 2020, most of whom received Flu+Bu+ATG+4GyTBI conditioning, PBSCs, and additional GVHD prophylaxis with MTX+CSA, the predictive utility was as follows (as of May 2021, Khanolkar/Storek, unpublished): - At 3 mo posttransplant, patients with 3 mo posttransplant, patients with 5% drop of donor leukemia lineage cells from 3 mo had ~4-fold higher risk of relapse than patients with <5% drop (irrespective of T cell chimerism). o The 5% drop of donor leukemia lineage cells predicted relapse with PPV=79% and NPV=81%. Chimerism results are interpreted as shown in Table 2. 

# Summary
- Transplant recipients should be immunized according to the Guidelines of Community and Population Health Division ("Public Health"), Alberta Health and Wellness, posted at #toc-4 . For an abbreviated version of the adult schedule, see Appendix 1.

# Highlights of the Schedule:
- 6 mo posttransplant, start non-live vaccines (given at 6, 7, 8, 12, 14 and 24 mo)
- 24 mo posttransplant, start live vaccines (given at 24 and 27 mo) -contraindicated in patients with relapse or active cGVHD -wait until 3 mo after discontinuation of immunosuppressive therapy (systemic and topical) and no cGVHD activity. Discontinue valacyclovir 1 day before first VZV vaccine dose. - 36 mo posttransplant, check antibody levels to tetanus, hepatitis B, measles and rubella, and order boosters if needed.

# Background
The Albertan Guidelines were developed based on international guidelines, 1 keeping simplicity in mind. For example, the same schedule was developed for autologous and allogeneic transplant recipients, and similar schedule was developed for children and adults. The reason for simplicity is to minimize confusion that could arise from the fact that many parties are involved in the vaccination process, including the transplant physician, the hematologist/oncologist to whom an autologous transplant recipient is referred after autologous transplantation, the Public Health vaccination clinic administering the vaccines and, in special scenarios, Infectious Disease specialist, Public Health specialist ("Medical Officer of Health") or Travel Clinic physician.

# Practical Considerations
- Antibody levels to vaccine-preventable diseases decline during 1-10 years posttransplant if the recipient is not revaccinated. o The decline is more substantial in allogeneic compared to autologous HCT recipients. Therefore, and because influenza, pneumococcal disease and shingles are less frequent after autologous than allogeneic HCT, vaccination is less important after autologous than allogeneic HCT. Why Vaccinate?
-  If no relapse  If no active GVHD  Off of immunosuppressive drugs for at least 3 mo  Off of IVIG for 7 months (efficacy of live vaccines is decreased with IVIG; wash-out of 3 months is probably sufficient; however, Public Health official recommendation is to wait 7-11 months) o Probably safe as early as 1 year posttransplant, so could be used during outbreak - GVHD status consideration o Patients with active GVHD and/or treated with systemic immunosuppressive drugs mount lower antibody responses to vaccines than patients without GVHD/off of immunosuppressive drugs. However, even the low response is thought to protect at least some patients from influenza, Covid-19, or pneumococcal disease. Given that protection against influenza, Covid-19, and pneumococcus is more important in these patients (compared to patients without GVHD/off of immunosuppressive drugs), immunization with non-live vaccines should not be delayed due to GVHD/immunosuppressive therapy. 

# Summary
- For children, cord blood as a stem cell source might be as useful as bone marrow for some conditions - For adults, data supports cord blood as a stem cell source when no HLA-matched or haploidentical donor is available. - Total nucleated dose and degree of HLA-matching are the most important factors when selecting units for cord blood transplantation - For single umbilical cord blood transplantation in malignant conditions:
- TNC at freezing must be 2.5 x10 7 /kg o In comparing available units with TNC  3.0 x10 7 /kg, prioritize highest degree of HLA match. Increased TNC dose beyond this threshold is not associated with improved outcomes o In comparing smaller dose units (TNC < 3.0 x10 7 /kg) prioritize dosing over HLA match o HLA matches must be 4/6, 5/6, or 6/6 at HLA-A/B/DRB1 allele level matching o Where possible, higher TNC doses (ie  3.5 x 10 7 /kg) are preferred for units with 4/6 HLA disparity o HLA-A or -B mismatch is preferable over DRB1 mismatch o Donor specific antibodies are preferred to be absent o Other factors to consider if multiple units available (see text)
 Quality of unit based on collection centre characteristics  High-resolution allele-level HLA-matching  Availability of RBC-depleted units  Unit CD34+ count - For non-malignant conditions o higher TNC doses are required (5.0 X 10 7 /kg) o wherever possible a high degree of HLA matching is preferred o Absence of HLA-antibodies likely has greater importance than in transplant for malignant disease - Double unit cord blood transplantation is feasible if no adequate single unit is available. Selection of DUCBT units involves o selection of two best available cord blood units, each with minimum TNC  1.5 x10 7 /kg (preferred  2.0 x 10 7 /kg) and best HLA match to recipient o unit-unit HLA match should not be considered in selection of double unit graft since there is no association with sustained engraftment or speed of neutrophil engraftment - Conditioning for adult UCBT is myeloablative and uses our centre's preferred regimen (Flu/Bu/low dose TBI). This and many other myeloablative regimens have been reported without clear superiority of one regimen over another. - Conditioning for pediatric UCBT generally involves higher dose TBI in addition to cyclophosphamide and fludarabine to optimize engraftment (standard North American practice) - GVHD prophylaxis after UCBT is with mycophenolate mofetil (~15 mg/kg bid) to day 35 and cyclosporine to day 84 and. Methotrexate is not used as it has been associated with delayed engraftment/graft failure. ATG is not used as it has been associated with prohibitively high rates of posttransplant infection. - Red blood cell replete units will be thawed and washed to remove cellular debris prior to infusion.
Buffy coat and red blood cell depleted units will be thawed and diluted. DMSO content for thawed and diluted products will not exceed 5 mL/kg of 20% DMSO solution per day.

# Background
The first successful umbilical cord blood transplantation was performed in 1998, on a 5-year old male with severe Fanconi's anemia who received cord blood stem cells from an HLA-identical sibling 1 . Decades later his graft remains durable with no evidence of disease. Since that time, umbilical cord blood stem cells have become a well-established source of hematopoietic stem cells for allogeneic stem cell transplantation. More than 40,000 patients have undergone UCBT for malignant and nonmalignant conditions. In Canada, in the year 2007, 68% of all unrelated pediatric stem cell transplants, and 9% of unrelated adult stem cell transplants were performed with umbilical cord blood stem cells. Umbilical cord blood transplant use is declining in Canada and in most centres across world the owing in part to increased experience with, improved outcomes, and cost efficacy reported with the use of haploidentical donors.
When selecting a donor source for hematopoietic stem cell transplantation, we consider the impact of the donor source on transplant outcomes, including engraftment, graft-versus-host disease (GVHD), treatment-related or non-realpse mortality (TRM and NRM), relapse incidence and relapse free survival (RFS), and overall survival (OS). Urgency of transplantation and timely availability of donor stem cells is also an important consideration. A 10/10 human leukocyte antigen (HLA)-matched unrelated donor graft is first choice for the 70% of patients who must look outside their families for donors. Unfortunately, unrelated volunteer registries are limited in ability to provide a prompt source of hematopoietic stem cells for many patients, particularly for ethnic minorities: 60% of Caucasians and only 20-25% of ethnic minorities will be matched to an unrelated donor on a registry. Haploidentical related donors and mismatched unrelated donors are feasible options for those without matched related or unrelated donors, as outlined in the AHS BMT Standard Practice Manual chapter on Donor Selection. In cases where a search for matched related, unrelated, or haploidentical donors is or is suspected to be unfruitful a simultaneous cord blood search should be performed, especially if transplantation is urgent. Advantages of umbilical cord blood transplantation include:
- Rapid availability -median 25-36 days sooner than unrelated volunteer marrow/blood stem cells - Larger donor pool -tolerance of 1-2/6 HLA mismatches (i.e. 4-6/6 HLA-A, -B antigen, and DRB1 allele) - Lower incidence and severity of acute graft-versus-host-disease (GVHD) - Lower incidence of chronic GVHD - Lower risk of viral transmission (e.g. CMV, EBV) - Lack of donor attrition - Lack of risk to donor Disadvantages of umbilical cord blood transplantation include:
- Lower number of progenitor cells and stem cells -higher risk of graft failure, delayed engraftment - Delayed immune reconstitution -increased risk of infection leading to death - Not possible to obtain more cells for future treatment (e.g. donor lymphocyte infusion, second transplant) - Genetic history of donor unknown

# Umbilical Cord Blood Transplantation vs Transplantation Using Other Grafts
There is little randomized clinical trial data comparing transplantation of umbilical cord blood (UCB) vs. related or unrelated marrow or peripheral blood stem cell donors. The best data available comes from retrospective single centre and registry data available for both children and adults.
Umbilical cord blood transplantation using related donors is performed almost exclusively in children. A Eurocord and IBMTR (International Bone Marrow Transplant Registry) joint study compared children who received umbilical cord blood from HLA-identical siblings (n=113) to children who received marrow from HLA-identical siblings (n=2052) 2 . Umbilical cord blood recipients had slower engraftment and lower risk of GVHD compared to those who received marrow, and there was no difference in relapse-related deaths, 100-day mortality, and overall survival (3-yr overall survival (OS) 86% vs. 84% for non-malignant conditions, 46% vs. 53% for malignant). Factors influencing outcomes after related HLA-identical UCBT in children were found to be cell dose, GVHD prophylaxis not including methotrexate, and disease status at transplantation 3 . When UCBT was compared to unrelated marrow donors in children with acute leukemia, there were lower rates of acute GVHD in the HLA-matched umbilical cord blood group compared to HLA-matched bone marrow (RR 0.45, p=0.0387), similar survival outcomes between bone marrow and 1-2 antigen mismatched cord blood, and improved survival with HLA-matched cord blood compared to bone marrow 4 . Thus, it appears that umbilical cord blood as a stem cell source is as useful as bone marrow for children requiring allogeneic hematopoietic stem cell transplantation. In adults, the large retrospective EBMT/CIBMTR (European Group for Blood and Marrow Transplantation / Center for International Blood and Marrow Transplant Research) study compared leukemia-free survival for umbilical cord blood, peripheral blood progenitor cell, and marrow transplantation in 1525 patients aged 16 or older. 5 When compared to 7-8/8 allele-matched peripheral blood or marrow (matched unrelated  and mismatched unrelated donor ) transplantation, UCB transplantation had comparable leukemia-free survival, higher transplant-related mortality, and lower rates of graft-vs-host disease. The authors concluded that data support UCB transplantation (UCBT) for adults with acute leukemia when no HLA-matched donor is available for urgent transplants. Similarly a large 2020 Japanese registry study including 4150 adult patients comparing 7/8 MMUD (n = 488) to UCB (n= 3662) acute myeloid leukemia (AML) transplant recipients from 2008 to 2017 reported comparable OS (46 v 54 %; HR 1.01; p= 0.89), NRM (HR 1.16; p=0.16), and relapse rates (HR 0.85; p = 0.08) in both groups, and decreased grade II-IV aGVHD (HR 0.76; p<0.001) cGVHD (HR 0.77, p = 0.002) in UCBT patients. 27 Other comparisons have reported advantages of MMUD transplant over UCBT. A 2019 retrospective EBMT registry study including 2963 total MUD, MMUD, and UCB transplant recipients recently reported lower relapse incidence (HR = 0.8, P = 0.02) lower NRM (HR = 0.7, P = 0.008), improved GRFS (HR = 0.8, P = 0.01), and improved OS (HR = 0.7, P < 0.001) in 9/10 MMUD (n=677) compared to UCB recipients (n=285). 28 Given the absence of consistent data favoring MMUD over UCB transplant, selection between these donor sources be should done a case by case basis factoring in donor, disease, and patient characteristics.
Retrospective comparisons, meta-analyses, and small prospective trials have recently reported data supporting improved transplant outcomes with haploidentical (haplo) donor hematopoietic cell transplant (HCT) when compared to UCBT.  In two meta-analyses from 2020 29 and 2019 32 with overlapping study inclusion reporting on 2,793 (1,432 haplo; 1,361 UCB) and 3,434 (1,759 haplo, and 1,675 UCB) mostly adult transplant recipients for hematologic malignancies, haplo HCT was associated with decreased rates of acute GVHD, increased rates of chronic GHVD, decreased nonrelapse mortality, improved relapse-free survival, and improved overall survival.
Umbilical cord allotransplantation at our centre is thus considered in cases where a suitable matched related, unrelated, or haploidentical donor is not available. Mismatched unrelated donors are preferred over cord blood sources, but this selection should nonetheless be reviewed on a case by case basis.

# Selection of Cord Blood Unit for Single Unit Cord Blood Transplantation

# Cell Dose & HLA Match
Both the total nucleated cell dose and degree of HLA-match of the umbilical cord blood unit in single cord blood transplantation have a strong impact on survival via effect on transplant-related mortality. In a large 2010 retrospective single centre analysis of 1061 predominantly pediatric recipients of single-unit myeloblative UCBT for the treatment of hematological malignancies from 1993 to 2006, the best transplantation outcomes were in recipients of 6/6 units regardless total nucleated cell (TNC) dose, though median dose was notably 4.0x10 7 /kg. 6 Recipients of 4/6 HLA-matched units required a TNC 5.0x10 7 /kg to achieve comparable TRM and RFS to that of recipients of 5/6 units with a TNC of 2.5x10 7 /kg. This study may suggest that that the greater the degree of HLA disparity, the higher the required TNC dose to ensure transplantation survival 6 .
More recent reports have suggested that beyond a minumum TNC threshold, HLA disparity may not have adverse impact of NRM or other transplant outcomes. A 2019 Japanese registry study of 1,355 adults receiving UCB allogeneic HCT (alloHCT) between 2003 and 2016, including only those with minimum TNC dose of 2 x 10 7 /kg compared pairings above or below the median TNC dose (2.68 x 10 7 /kg) and with either 1 or 2 mismatches. 34 No advantage was seen in those with the least degree of mismatch and higher cell dose when compared to other pairings with greater mismatch, smaller cell dose, or both. TNC in the highest quartile was associated with improved ANC engraftment rates when compared to the lowest quartile, but higher TNC dose quartiles were otherwise not associated with improved engraftment, relapse, or survival outcomes, suggesting against benefit of increased TNC dosing beyond a given minimum threshold. In the large 2014 EBMT and Eurocord study addressing the impact of allele-level matching on outcomes, in multivariate analysis, the effect of a TNC count 3 x 10 7 kg on NRM was independent of HLA disparity, and held true when patients were analyzed as pediatric and adult subcohorts. 35 In a phase 3, 320-patient multicenter randomized controlled trial (RCT) comparing single UCB (SUCB) to double UCB (DUCB) alloHCT, single units were eligible if above a TNC of 2.5  x 10 7 /kg regardless of HLA mismatch, included 39% 4/6 mismatches, and demonstrated similar outcomes with respect to neutrophil engraftment, relapse, PFS, and OS when compared to DUCBTs. 36 The 2019 NMDP/CIBMTR Guidelines on cord unit selection suggest a minimum 2.5 x 10 7 /kg minimum dose per single unit and do not specify higher minimum doses for differing degrees of HLA disparity. 37 Other studies  consistently demonstrate cell dose to be the most important factor on survival outcomes, and the EBMT and NMDP/CIBMTR guidelines have recommended using 2.5-3x10 7 total nucleated cells/kg at collection for patients with malignant disease and 5.0x10 7 nucleated cells/kg for those with non-malignant disease. 7,37 An increasing number of HLA mismatches is associated with delayed engraftment, higher treatmentrelated mortality, higher rates of chronic GVHD, and in malignant diseases, decreased relapse rates. 7 As greater HLA disparity is not associated with improved relapse outcomes in nonmalignant diseases, optimal HLA matching is important in these cases. When choosing between multiple cord units that meet the minimum cell dose requirement, optimal HLA matching should be prioritized. Memorial Sloan-Kettering Cancer Center (MSKCC) guidelines for single UCBT suggest a minimum nucleated cell dose of 2.5 x 10 7 /kg with 1 or 2 mismatches at the HLA-A, -B antigen, or -DRB1 allele. 13 There is no data to guide dosing of TNC by actual versus ideal or adjusted body weight, thus the dose should be based on the patient's actual weight at time of transplantation. Based on the above data, at our centre selection of a single umbilical cord blood transplantation in malignant conditions requires a minimum TNC at freezing of 2.5 x 10 7 /kg. When comparing available units with TNC 3.0 x10 7 /kg, the highest degree of HLA match should be prioritized, as increasing TNC dose beyond this threshold is not associated with improved outcomes. In comparing smaller dose units (TNC < 3.0 x10 7 /kg) we prioritize dosing over HLA match. Where possible higher TNC doses (ie  3.5 x 10 7 ) are preferred for units with greater (ie 4/6) HLA disparity.
HLA matching in UCBT is based on HLA antigen typing for -A and -B, and allelic typing for HLA-DRB1. A single institution retrospective analysis of 79 adults with AML who received single unit UCBT was analyzed for the impact of directional donor-recipient HLA disparity using allele-typing at HLA-A, -B, -C, and DRBI. 14 With the extended high-resolution typing, the donor-recipient compatibility ranged from 2/8 to 8/8, but this did not have a negative impact on non-relapse mortality, GVHD or engraftment. The 5-year cumulative incidence of relapse was 44% vs. 22% for patients receiving UCB units matched 6/8 or <6/8, respectively (p=0.01). On multivariate analysis higher HLA-disparity in the GVH direction and first complete remission at time of transplantation were the only variables significantly associated with an improved DFS. The effect of allele-level matching on non-relapse mortality in 1568 single umbilical cord blood transplantations for hematological malignancy was published in 2014. 15 Only 7% of donor-recipient pairs were matched at HLA-A, -B, -C, and DRB1; 15% were mismatched at one, 26% at two, 30% at three, 16% at four, and 5% at five alleles. Only 54% of units matched at HLA-A, -B, and -DRB1 were actually matched at the allele-level at all loci. Non-relapse mortality was higher with units mismatched at one (26%), two (26%), three (34%), four (37%), or five alleles (41%) compared to HLA-matched units (9%). Cell dose <3.0 x10 7 /kg was associated with higher NRM independent of HLA-match. Neutrophil recovery was lower with mismatches at 3-5 alleles but not at 1 or 2 alleles. These data support allele-level HLA-matching in the selection of single UCB units whenever possible.

# Donor Specific Antibodies (DSA)
Since most UCBT are performed with HLA-mismatched UCB units, the presence of anti-HLA donorspecific antibodies in the patients against the UCB can result in failure or delay of engraftment. Anti-HLA antibodies before transplant may occur due to alloimmunization to HLA through blood transfusions, pregnancy, and also in some unexposed individuals. In the UCBT setting, few studies with controversial results are available on the impact of DSA on outcomes. One analysis showed an increased risk of graft failure and lower survival for patients with positive DSA undergoing single (n=386) or double (n=73) UCBT. 16 Another report showed no association between the presence of DSA and transplant outcomes in 126 double UCBT recipients. 17 Presence of DSA was found to be associated with higher 1-year TRM (46 v 32%; p=0.06) and lower engraftment (44% vs. 81%, p=0.006) in patients with or without antibodies, respectively. 18 Based on these data, whenever possible, it is important to avoid selecting a unit when the patient has donor specific anti-HLA antibodies. Other factors to consider in selecting cord blood units: - Unit quality, measured by practices of the bank with from which it originates, is associated with increased unit potency including post-thaw CD34+ cell recovery and viability. Where possible it is desirable to obtain cord blood units that were more recently cryopreserved, from banks that are FACT-accredited, that store RBC-depleted cord units, at adequate volume (25 cc thawed volume per unit), and that are closer in location. 37 - CD34+ cell count can be considered when choosing between multiple cord units that are otherwise similar from the same bank. NMDP/CIBMTR guidelines suggest a minimum CD34 + count of  1.5 x 10 5 kg. 37 Given variation in and non-standardization of CD34 + count and viability measurements, interpretation of reported CD34 + count should be done cautiously, particularly if it appears discrepant from TNC dose. 37,38 - Red blood cell (RBC) content of the unit. Buffy coat enriched and RBC depleted units should be considered over RBC replete units. RBC replete units contain red cell debris and free hemoglobin, which can be associated with infusion reaction and washing of these RBC replete units can result in progenitor cell loss. - Natural killer cell immunoglobulin-like receptor mismatch, non-inherited maternal antigens and inherited paternal antigens may influence decisions about which units to select in the future

# Double Unit Umbilical Cord Blood Transplantation
The use of single unit UCBT, while more common for pediatric recipients, is limited for older recipients since many adults do not have access to a single cord blood unit with the recommended TNC dose. Strategies for ex-vivo expansion of UCB units are being actively explored in the literature with some early phase I/II trials showing promise.  These strategies have yet to be standardized or widely adopted and warrant further exploration.
Double unit UCBT as a strategy to augment cell dose of the graft has been successful with improved sustained donor engraftment and post-transplantation survival compared with historic SUCBT controls. 19 Sustained hematopoiesis is accounted for by only one of the two units, with demonstration of dominance as early as Day +21 post-transplant. Higher CD3 + cell dose and percentage of CD34 + cell viability was associated with unit dominance. 19 The exact biological mechanism responsible for single-donor predominance after double unit CBT remain incompletely understood. Accumulating reports support the use of DUCBT to overcome the cell dose barrier in adults. In one study with 177 patients who underwent myeloablative UCBT, DUCBT recipients experienced lower relapse rates (19 vs 34% at 5-years), higher rates of GVHD (acute GVHD 48 vs 29%; chronic GVHD 18 vs 10%), and higher RFS (51 vs 40%) when compared to SUCBT recipients. 20 Given that either unit may engraft after a double unit UCBT, each unit of a double-unit graft is equally important and the same unit selection principles should apply to both units. Optimal strategies for balancing cell dose against HLA match are not well established. Of note there is no relationship between unit-unit HLA match and the likelihood of sustained donor engraftment. 19  HLA-A or -B antigen or -DRB1 allele mismatches or 10/10 HLA-allele matches in 84 recipients of double unit UCBT, there was no association between unit-unit HLA match and sustained engraftment, speed of neutrophil engraftment, or unit dominance. 19 Thus, unit-unit HLA match should not be considered in the selection of a double-unit graft, particularly at the expense of available grafts with higher cell doses. MSKCC guidelines recommend each DUCBT have a minimum TNC of 2.0x10 7 /kg, with preference for HLA matching above this TNC threshold, and unit-unit HLA match is not considered. 13 NMDP/CIBMTR guidelines and most DUCBT studies in adult and pediatric populations recommend or require a minimum TNC dose of  1.5 x 10 7 /kg for DUCBT, suggesting a less stringent TNC threshold may be safe and effective. 37,43 Whether DUCBT is preferable SUCBT when the cell dose in one unit is acceptable is unknown in the adult setting. In The Blood and Marrow Transplant Clinical Trials Network randomized trial (BMT CTN 0501) was a phase III trial that randomized patients to receive a single (n=113) or double (n=111) UCBT, with median pre-cryopreserved TNC dose of 4.8 and 8.9 x10 7 /kg, respectively. 21 The results of this study showed no survival advantage after DUCBT compared to SUCBT in children with hematological malignancies (1 year OS 65% vs. 71%, p=0.13). Except for a higher risk of grade III-IV acute GVHD in recipients of a double UCBT, all outcomes were similar between the two groups. Similar findings were reported in a large 2019 systematic review comparing DUCBT to SUCBT that included the above RCT and 24 additional retrospective and prospective reports. A total of 6571 total patients were included, with 12 of 25 studies enrolling adults exclusively. 43 DUCBT was associated with higher incidence of acute and extensive cGVHD but with lower relapse incidence, and outcomes were ultimately similar between DUCBT and SUCBT for NRM, RFS, and OS. Authors suggested the increased GVH and presumed GVL effect reported here may suggest that DUCBT could be considered in patients with higher risk disease, but this possibility has yet to be explored in a prospective randomized fashion. 

# Schema for Unrelated Cord Blood Unit Selection
Step 1
Step 2
Step 3
Step 4

# Infusion of Cord Blood Units
Cord blood units are processed and infused according to established standard operating procedures. Processing requirements for Cord Blood Units are determined by transplant physician, in consultation with the Cellular Therapy Laboratory (CTL), prior to planned infusion. For pediatric patients, please reference document BMTS20015. - For double cord blood transplants, the first unit must be thawed, processed and administered safely prior to thaw and processing of the second unit.
Evaluate search reports for units 4-6/6 HLA-matched with TNC 2.5 x 10 7 /kg.
Review information and bank of origin for each unit.
Obtain missing unit information.
Prepare cord blood search summary report.
For units with TNC  3.0 1 Rank units according to HLA-A, -B antigen, -DRB1 allele match. 2 List highest to lowest TNC within each HLAmatch grade.
If suitable cord unit available, proceed with single unit UCBT.
For units with TNC<3.0 1 Rank units according highest TNC first 2 List highest to lowest with comparable TNC by HLA-A, -B antigen, -DRB1 allele match 

# Conditioning
Non-relapse mortality has historically been an important contributor to adverse outcomes in UCBT.
In the aim of reducing NRM, many studies have explored reduced intensity conditioning regimens. The largest and most recent comparison of conditioning approaches was reported in a 2016 EBMT Eurocord registry study involving adults transplanted for AML with SUCBT or DUCBT from 2004 to 2013. 44 A total 894 adults who underwent myeloablative (MAC, n = 479) or reduced intensity conditioning (RIC, n = 415) were included. MAC regimens were varied and included 40 (8%) patients receiving Flu/Bu based ablative conditioning. Compared to MAC UCBMT recipients, RIC recipients had similar neutrophil engraftment and rates of acute and chronic GVHD. RIC recipients also had a higher incidence of disease relapse, but lower NRM, ultimately resulting in comparable PFS, GRFS, and OS between both groups. MAC regimens were not compared amongst each other.
Given these findings, in adult patients, our centre prefers a myeloablative Flu/Bu/low dose TBI conditioning platform, the same regimen as that used for MRD, MUD, MMUD and haploidentical alloHCT at our centre, and a regimen with which we have extensive experience. Pediatric patients generally receive 1200 cGy TBI with cyclophosphamide and fludarabine to optimize engraftment, as per common North American practice.

# GVHD Prophylaxis
Use of ATG has been associated with decreased survival primarily due to infections.  Use of methotrexate has been associated with delayed engraftment and graft failure. 26 Some evidence suggests that delayed or failed engraftment is lower with a mycophenlate mofetil/calcineurin inhibitor (MMF/CNI) based regimen than with methotrexate. 45 Exploration of reduced-dose methotrexate, often less than half the standard dose, has in some reports been also associated with lower NRM, infectious complications, and improved engraftment 45,46 and in one retrospective three arm study, comparable engraftment to that seen with MMF/CNI based prophylaxis. 47 Further comparative and prospective studies are required to establish the optimal GVHD prophylaxis regimen in UCBT.
The most frequent GVHD prophylaxis reported in UCBT (including in the US BMT CTN study 1101) remains MMF/Cyclosporine (CSA), which in the absence of clear evidence pointing to an optimal regimen, is the prophylaxis regimen we prefer at our centre (MMF to day 35 and CSA to day 84 in adults, variable duration in children).

# Calgary Results
Among 23 adult pts who received UCB between 2004 and 2020 and were followed for >100 days (if survived), 8 patients are alive at >5 y posttransplant. Of the 15 patients who died, 4 died due to an infection (not associated with GVHD), 4 due to GVHD, 3 due to relapse and 4 due to other (typically multi-organ failure). 

# Summary
- Donor/recipient pairs of different blood groups may exhibit major ABO incompatibility (the recipient has pre-formed hemagglutinin antibodies reactive against donor red blood cells), minor ABO incompatibility (the donor has pre-formed hemagglutinin antibodies reactive against recipient red blood cells), or bidirectional (the donor and recipient both have hemagglutinin antibodies reactive against the other). - There is no consistent evidence that ABO incompatibility unduly influences clinically relevant outcomes (e.g., survival, GVHD). - An ABO compatible donor is preferred over an ABO incompatible donor to minimize the risk of non-lethal complications like hemolytic anemia or pure red cell aplasia. - Major ABO incompatibility, including bidirectional incompatibility:
- For adult recipients, if the red cell volume is >30mL, the product is split into aliquots with no greater than 30mL red cells per unit. If the initial incompatible red cell volume is <30mL, no further action is taken. No more than 30mL of incompatible red blood cells should be infused in a 6-hour period. o For pediatric recipients, the accepted range for ABO incompatible blood volume transfused is 0.2 to 0.5 mL/kg. The transplant physician will be contacted with the volume of incompatible red blood cells and will direct Cellular Therapy Lab (CTL) on desired final red blood cell content per infusion bag. CTL will aliquot and/or red cell reduce product as necessary for infusion into the patient. o For products with very large volumes of red cells, where dividing into several aliquots is not practical, red cell reduction by centrifugation or Hespan can be considered.

# - Minor ABO incompatibility:
- No action is taken as local validation data at CTL has indicated no adverse reactions associated with minor ABO incompatibilities.

# Background
Up to 50% of related and 50% of unrelated donor transplants involve an ABO incompatible donor and recipient, not including differences between minor red cell antigens 1, 2, 3 . Donor-recipient pairs with the same ABO blood type are said to be compatible. Minor incompatibility occurs when the donor has antibodies against recipient ABO antigens, and major incompatibility occurs when the recipient carries antibodies against donor red cells. When both occur in the same donor-recipient pair, a bidirectional incompatibility is present, as shown in Table 1 below 3,4 . Major incompatibility can result in acute hemolytic transfusion reaction at the time of stem cell infusion and delayed red cell engraftment. Minor incompatibility rarely causes at the time of transplant hemolysis from infusion of incompatible donor plasma, but can result in delayed transfusion reaction 7-14 days post-transplant www.ahs.ca/guru BMT Standard Practice Manual Last Revised: September 14, 2021 Effective: September 14, 2021 Background Survival after hematopoietic cell transplant (HCT) has improved. 3 Survivors, however, face significant health challenges that contribute to morbidity and mortality even late after transplant. Among HCT survivors, the 15 year cumulative incidence of a severe or life threatening chronic health condition, such as stroke, myocardial infarction, diabetes and subsequent neoplasm, is approximately 40%: the cumulative incidence does not differ significantly between recipients of autologous (auto) and allogeneic (allo) HCT. 4 As a result, the risk of death after both allogeneic and autologous HCT, remains significantly higher than that of the general population even many years post HCT. 5,6 Therefore, it is imperative to have a structured long-term follow-up plan for survivors of HCT. This document will summarize the current literature with respect to late effects after HCT and will provide guidelines for clinical practice. The following important aspects of post-HCT survivorship care have already been reviewed in detail elsewhere in the ABMTP standard practice manual and can be found in their respective chapters:
- Diagnosis and management of chronic graft-versus-host disease (cGVHD)
- Management of post-HCT relapse - Infection prophylaxis and vaccination

# Frequency of Follow-up
Due to the potential for onset of cGVHD, the recommended follow-up interval for allo-HCT recipients between day 80 and 1 year post-HCT is every 4-6 weeks. Those suffering from GVHD, infection, relapse or other toxicity may need to be evaluated more frequently. Follow-up of allo-HCT recipients beyond 1 year post-HCT and of auto-HCT recipients may be individualized. However, long-term follow-up visits for allo-HCT recipients should be at least annually.

# Transitioning from Pediatric to Adult Post-HCT Care
In Alberta, transition from the pediatric to adult HCT centre for follow-up care is not typically required. Survivors of pediatric HCT are typically followed into adulthood and indefinitely in the Alberta Children's Hospital long-term follow-up/survivorship clinic.

# Cardiovascular Disease
Cardiovascular disease is a major cause of late non-relapse mortality in survivors of HCT. Compared to the general population, HCT survivors have a significantly increased cumulative incidence of cardiovascular death (incidence rate difference 3.6 per 1000 person years) and a significantly higher incidence of cardiovascular risk factors, such as diabetes and hypertension, when compared to age and sex matched controls. 7 Cardiovascular disease after HCT can be conceptualized as arterial disease (cerebrovascular, peripheral arterial and coronary artery disease) and cardiac disease (particularly congestive heart failure but also constrictive pericarditis and valvular disease) with 6 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: September 14, 2021 Effective: September 14, 2021 allogeneic HCT survivors being at higher risk of the former and autologous HCT survivors being at higher risk of the latter. 8 The cumulative incidence of arterial events among allo-HCT recipients is in excess of 20% at 20 years and the median age at first myocardial infarction is approximately 53 years, which is at least a decade earlier than that of the general population. 8 In a large single centre study, the cumulative incidence of 2 cardiovascular risk factors (of hypertension, dyslipidemia and diabetes) at 10 years after HCT was ~40% for allo-HCT survivors and 26% for auto-HCT survivors. 9 Older age and obesity at HCT, TBI (>2 Gy) and grades 2-4 aGVHD were risk factors for acquisition of cardiovascular risk factors post-HCT. In keeping with these findings, the prevalence of the metabolic syndrome in alloand auto-HCT recipients is double that of the age-matched general population. 10 Risk factors for occurrence of cardiovascular disease after HCT encompass both traditional risk factors in addition to chest irradiation, GVHD, and exposure to anthracycline chemotherapy. 8,9 Healthy lifestyle choices such as physical activity and fruit/vegetable intake are associated with a lower risk of cardiovascular disease after HCT. 11 Current Canadian guidelines for the general population recommend measurement of a lipid panel and glucose in women and men  age 40 every 5 years. 12 In a large single centre review, the cumulative incidence of late congestive heart failure (CHF) in auto-HCT survivors was approximately 10% at 15 years post-HCT-a 4.5 fold increased risk over that of the general population. 13 Pre-HCT anthracycline exposure, particularly cumulative dose  250 mg/m 2 is the primary driver of CHF risk, although significant modifiers that increase this risk further include younger age at anthracycline exposure, female sex, chest radiation, hypertension and diabetes. 4,8 Recommendations:
- All patients should be counselled with respect to lifestyle modifications that reduce the risk of cardiac events, such as tobacco avoidance, adequate physical activity, maintaining a healthy weight and a healthy diet. - For all other auto-HCT recipients: screening and management per the general population guidelines. - Lipid and glucose screening may begin earlier than age 30 for those with one or more risk factors for cardiovascular disease including obesity, smoking, family history of early cardiovascular disease, diabetes, chest radiation or history of GVHD requiring systemic immunosuppression. - Those with a history of cumulative dose of anthracycline  250 mg/m 2 should have yearly history and physical exam for signs/symptoms of CHF and aggressive management of cardiovascular risk factors as outlined above. Echocardiograms at yearly intervals for 5 years post-HCT may be considered for those at highest risk of CHF (i.e. those with one or more risk factors in addition to anthracycline exposure, including younger age at anthracycline exposure, female sex, chest radiation, hypertension or diabetes).

# Bone Health
Loss of bone density after HCT is well described and typically occurs in the first 6-12 months posttransplant. 12 Beyond one year post-HCT, recovery of bone mineral density (BMD) to a variable degree may occur if patients do not experience additional risk factors for bone loss. Additional risk factors for osteoporosis include prolonged exposure to corticosteroids and calcineurin inhibitors (i.e. ongoing treatment of cGVHD), major weight loss, malnutrition, older age at HCT and female gender. 14,15 In a recent study, the prevalence of osteoporosis and osteopenia in patients experiencing moderate-severe cGVHD was 17% and 60%, respectively. 16 The estimates in the literature of the incidence of osteoporosis and osteopenia after HCT in those without cGVHD vary widely; however, both auto and allo-HCT recipients, particularly females and older males, have a marked increase in risk of fracture compared to that of the general population. 15 At least two studies have revealed a higher risk of fracture after auto-HCT versus allo-HCT. 15,17 Finally, degree of bone loss after HCT does not seem to directly correlate with risk of fracture, 18 highlighting the potential importance of using clinical assessment tools for fracture risk (such as FRAX) which take into account BMD and clinical factors. The Alberta Toward Optimized Practice (TOP) guidelines for osteoporosis provide recommendations for therapy and follow-up DXA based on the 10 year probability of fracture as calculated by FRAX. While FRAX takes into account corticosteroid exposure in general, it may underestimate the fracture risk for those who are receiving long courses of moderate to high doses of corticosteroids (i.e. cGVHD) and those who have more severe bone loss at the spine versus the hip (as it does not take into account BMD at the lumbar spine). There are, however, no universally agreed upon adjustments to fracture risk estimates for these variables. The recommendations for those with cGVHD below are generally in agreement with the 2017 American College of Rheumatology guidelines for the management of corticosteroid-induced osteoporosis. 19 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: September 14, 2021 Effective: September 14, 2021
- Referral to a nephrologist should be considered when estimated GFR is <30 mL/min, for management of CKD with proteinuria or for workup of CKD of unknown etiology.

# Pulmonary Disease
HCT recipients are at risk of both late infectious and non-infectious pulmonary diseases. Late infectious pulmonary complications include recurrent sinopulmonary infections, Pneumocystis and fungal infections. The approach to late pulmonary infections is addressed elsewhere in these guidelines (bacterial/pneumocystis prophylaxis, fungal prophylaxis and vaccination chapters). Late onset non-infectious pulmonary complications (LONIPCs) mainly affect allo-HCT recipients. LONIPCs are very rare after autologous-HCT-the vast majority of non-infectious pulmonary complications after auto-HCT occur in the peri-engraftment period. 33 The most common LONIPCs are summarized in Table 2 and include bronchiolitis obliterans syndrome (BOS) (a manifestation of cGVHD) and interstitial lung disease (the best defined being organizing pneumonia (OP), but diffuse alveolar damage, non-specific interstitial pneumonia and lymphoid interstitial pneumonia have also been described).  Idiopathic pneumonia syndrome, diffuse alveolar haemorrhage and pulmonary venoocclusive disease most often occur early (day 0-30) post-HCT, but rarely occur as a late toxicity. 37 In a recent prospective study, all LONIPCs were associated with cGVHD and were found to occur predominantly in the first 2 years after allo-HCT with a cumulative incidence of 20% at 3 years. 38 The LONIPCs consisted of BOS (40%), interstitial lung disease (22%), venous thromboembolic disease (16%) and restrictive lung disease with no interstitial lung or pleural disease (including cGVHD with cutaneous sclerosis) (15%). Those who experienced a LONIPC were at increased risk of death (HR 2.2); the main causes of death included relapse followed by respiratory causes and GVHD. Importantly, lower respiratory tract infection in the first 100 days after HCT, pre-HCT chest irradiation and low FEF25-75% at day 100 were risk factors for the development of a LONIPC. Evaluation of risk factors for BOS after allo-HCT have variably found older age, sex-mismatched HCT, history of aGVHD, busulfan-based conditioning, unrelated donor and peripheral blood stem cell graft to be associated with the development of BOS, while T-cell depletion is protective. 36 Finally, it should be noted that several chemotherapeutic agents (such as BCNU, bleomycin, busulfan and methotrexate) may contribute to or cause pulmonary toxicity. 22 
. Cumulative incidence of post-herpetic neuralgia (PHN) in patients treated with valacyclovir till 2 years followed by vaccination (New Strategy), patients treated with valacyclovir till approximately 1 year without subsequent vaccination (Old Strategy), and patients who continued valacyclovir till the end of follow up (Never off Antivirals). The difference between the New Strategy and the Old Strategy patients was significant (p=0.02). From Jamani et al. 16 Last Revised: April 13, 2021 Effective: April 13, 2021 Catheter Care Patients should be educated about their own catheter care in preparation for outpatient therapy. Written instructions for catheter care should be given to patients prior to discharge as per nursing policy and procedures.
Catheter Removal With all central line removals, informed consent shall be obtained and sterile technique maintained. Central line removals should be done in the supine position during exhalation to minimize air embolus risk.
All patients shall have their central lines removed once they are no longer using it regularly. All patients shall have line removed if they are eating/drinking well and not requiring transfusions or IV medications. A new line should be inserted if it is again needed (i.e. second transplant).
Prior to line removal, platelets should ideally be >50 and INR <1. 4. Send catheter for review if mechanical issue/infection potential suspected during line removal.

# Appendix 1.
Comparison of Seattle and Baltimore Diagnostic Criteria for SOS Seattle Criteria 22 Baltimore Criteria 23 Development of 2 of the following within 20 days of transplant: Hyperbilirubinemia (> 34 micromolar) within 21 days of transplant and 2 of the following:
- Hyperbilirubinemia (> 34 micromolar)
- Ascites - Tender hepatomegaly
- Hepatomegaly (may be painful) - Weight gain (> 2%)
- Weight gain (> 5%)  

# Prophylaxis
- Consider dexamethasone 10mg on morning of infusion and on days +1 and +2 if high risk for severe CRS or ICANS (e.g. 2 risk factors: axi-cel or brexu-cel, age >65, int/high modified EASIX, high tumor burden) - Consider levetiracetam 500mg BID prophylaxis from day 0 to +14 for patients receiving axi-cel or brexu-cel or who have other risk factors for ICANS. Duration of levetiracetam should be extended for patients who develop seizures or have ongoing ICANS, in conjunction with the neurology service. Grade 1 - Aspiration precautions, intravenous hydration - Withhold oral intake of food, medicines, and fluids and assess swallowing - Convert all medications and nutrition to IV if swallowing is impaired - Avoid sedating medications - Low-dose lorazepam (0.25-0.5 mg IV q8h) or haloperidol (0.5 mg IV q6h) for agitated patients - Neurology consultation - Fundoscopic exam for papilledema - MRI of the brain with and without contrast, MRI spine if focal neurological deficits - Consider diagnostic LP if other causes of encephalitis suspected - Consider tocilizumab 8 mg/kg IV if ICANS occurs in setting of CRS - Dexamethasone 10 mg IV x 1 dose and reassess in 6 hours - Start levetiracetam 500 mg bid prophylaxis if not already given Grade 2 - Workup and supportive care as described above - Tocilizumab 8 mg/kg IV if ICANS occurs in setting of CRS - Dexamethasone 10 mg IV q6-12h. Once ICANS improves to grade 1 or less taper and/or discontinue steroids if clinically appropriate - Consider ICU transfer if associated with grade > 2 CRS - Start levetiracetam 500 mg bid prophylaxis if not already given Grade 3 - Workup and supportive care as described above - ICU transfer - Tocilizumab 8 mg/kg IV if ICANS occurs in setting of CRS, if not administered previously - Dexamethasone 10-20 mg IV q6h for most patients. Consider treating focal brain edema with methylprednisolone 1 gm IV daily x 1-3 days - Increased intracranial pressure should be treated according to standard guidelines with acetazolamide 1000 mg IV followed by 250-1000 mg q12h (based on renal function and acid/base balance), elevate HOB. - Diagnostic LP if no improvement with treatment or if other causes of encephalitis suspected - Consider repeat neuroimaging every 2-3 days - Antiepileptic drugs as prescribed by neurology (avoid phenytoin and lacosamide due to cardiotoxicity) Grade 4
- Supportive care and workup as described above - ICU monitoring and mechanical ventilation for airway protection - Tocilizumab 8 mg/kg IV if ICANS occurs in setting of CRS, if not administered previously - Treat with methylprednisolone 1 to 2 g IV daily x 3 days followed by rapid taper - Consider anakinra, intrathecal hydrocortisone/methotrexate, or siltuximab if steroid refractory. Cyclophosphamide or ATG may be considered as treatments of last resort. - For convulsive status epilepticus treat according to established guidelines - Cerebral edema should be treated as per established guidelines, including hyperventilation, hyperosmolar therapy, frequent metabolic profiling and neurosurgical or anesthesia consultation for burst-suppression pattern EEG - Antiepileptic drugs as prescribed by neurology (avoid phenytoin and lacosamide due to cardiotoxicity) Considerations -Early Cytopenias (<30 days) 117 1. Mechanism -presumed LD chemotherapy related. 2. Supportive Transfusion as per standard transplant practice (see above).
- Evaluation and management of infections including viral and fungal. 4. Consider G-CSF if ANC not recovered by Day 7-10 a. Data inconclusive if G-CSF worsens CRS and ICANS b. Avoid in the presence of active CRS.
Considerations -Prolonged Cytopenias (>30 and <90 days) 117 1. overload prior to HCT, in particular patients with multiple red cell transfusion supports; however, whether the chelation improves outcomes has not been reported.
Taken together, it is reasonable to proceed with HCT if the liver function tests as measured by (Bilirubin, AST, ALT or ALP) are < 2 times upper limit of the normal reference range.
Seropositivity for Hepatitis B, C or HIV should not preclude HCT, recognizing that it affects peritransplant care, where viral prophylaxis or optimization of anti-viral therapy would be required. Unsurprisingly, viral hepatitis is associated with increased risk of reactivation, SOS, liver disease post-HCT and non-relapse mortality  . The use of Transient Elastography (Fibroscan) is suggested if there is clinical concern of cirrhosis 51 .
In general, it is reasonable to exclude patients with frank cirrhosis from HCT.

# Nutritional Evaluation
There is a paucity of evidence to suggest a specific nutritional state that would preclude HCT. However, is notable that patients that medically obese have similar post-autologous HCT outcomes as patients with a normal BMI  . Interestingly, obesity is associated with higher non-relapse mortality 56 but a lower relapse rate, resulting in similar overall survival in the allogeneic setting 57 and low BMI is associated with poor HCT outcome 56,58 . In contrast, a Chinese study would suggest that overweight and obese patients had a superior overall survival when compared with underweight and normal-weight patients (HR=0.60; 95% CI: 0.38-0.95) 59 .
Consequently, it may be reasonable to attempt to increase BMI before HCT, but it has not been reported whether this intervention improves outcome.

# Renal Function Evaluation
Renal dysfunction is associated with a higher morbidity and mortality in patients undergoing autologous HCT for myeloma  . Importantly, the value of autologous transplants studied in a randomized fashion only included patients with good renal function. In contrast, there is a paucity of data in the autologous setting in lymphoma given that traditional conditioning chemotherapy was not administered in patients with a serum creatinine >177micromol/L.
A similar argument applies in the allogeneic setting and maybe more pertinent given that acute renal injury can occur 15-18% of patients receiving allogeneic HCT 63 . Further, there is some evidence to support an increased risk of non-relapsed mortality in patients with renal impairment pre-HCT 64 . Indeed, long-term follow-up data suggests that the more severe the acute renal injury peri-HCT, the higher the likelihood of chronic kidney disease 65 . Interestingly, the risk of acute renal injury could be anticipated using the HCT-CI (see discussion later) 66 . Overall, it is reasonable to proceed with HCT where the Creatinine is < 177micromol/L and are < 2 times upper limit of the normal reference range. All other scenarios should be individualized.

# Dental Evaluation
The goal of pre-HCT dental assessments is to identify potential sources of infection during the peri-HCT period 67,68 . This appears to be good practice but there has been no clear evidence to support an association between radiographic periodontal disease and infections/mortality post-HCT 69,70 .

# Active Infections
It appears to be good practice that HSCT should be deferred if there is active infection or infection(s) that are not responding to therapy to decrease the odds of morbidity and mortality peri-HSCT.

# Comorbidity Indices
There are multiple standardized co-morbidity indices in clinical use that aims to aid pre-HCT assessments 71 . The purpose would be to incorporate and assign differing weights to characteristics considered in the above sections. However, it is important to note that not all characteristics are considered or considered in the same fashion in the derivation studies.

# Kaplan-Feinstein Scale
The Kaplan-Feinstein Scale (KFS) was originally developed to evaluate the impact of survival in patients with diabetes based on comorbid conditions and involves assigning Grades (range 1-3) to 12 comorbid conditions 72 . Artz et al. evaluated 105 consecutively enrolled patients who underwent HCT, receiving reduced intensity conditioning with fludarabine, melphalan, and alemtuzumab. A simple scale combining the Kaplan-Feinstein Scale (KFS) and Eastern Cooperative Oncology Group Performance Status (PS) scale PS enabled separation of high-from low-risk patients, with 6month cumulative incidences 50% and 15%, respectively for transplant-related mortality (P = .001) 73 .

# Pretransplant Assessment of Mortality Score -PAM Score
This risk score was developed at the Fred Hutchinson center and incorporates 8 pre-transplantation clinical variables: patient age, donor type, disease risk, conditioning regimen, FEV1, carbon monoxide diffusion capacity, serum creatinine level, and serum alanine aminotransferase concentration 32 . This score is useful for predicting the risk for death within the first 2 years after HCT.
The authors re-evaluated the PAM score using a contemporary cohort (2003)(2004)(2005)(2006)(2007)(2008)(2009) to update and recalibrate its predictive capability 74 and the score was also validated in non-Caucasians 75 . Importantly, the score was modified where carbon monoxide diffusing capacity, serum alanine aminotransferase, and serum creatinine concentrations were no longer significantly associated with 2-year mortality, whereas patient and donor cytomegalovirus serology was associated with mortality. However, there is also literature to support an assertion that the PAM score may not be useful in all 7 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: August 24, 2021 Effective: August 24, 2021 allogeneic 76,77 or autologous 78 settings. The following is a link to an online calculator: / EBMT Score This risk score was developed at the Fred Hutchinson center and incorporates 8 pre-transplantation clinical variables: patient age, donor type, disease risk, conditioning regimen, FEV1, carbon monoxide diffusion capacity, serum creatinine level, and serum alanine aminotransferase concentration 32 . This score is useful for predicting the risk for death within the first 2 years after HCT.
The authors re-evaluated the PAM score using a contemporary cohort (2003)(2004)(2005)(2006)(2007)(2008)(2009) to update and recalibrate its predictive capability 74 and the score was also validated in non-Caucasians 75 . Importantly, the score was modified where carbon monoxide diffusing capacity, serum alanine aminotransferase, and serum creatinine concentrations were no longer significantly associated with 2-year mortality, whereas patient and donor cytomegalovirus serology was associated with mortality. However, there is also literature to support an assertion that the PAM score may not be useful in all allogeneic 76,77 or autologous 78 settings. The following is a link to an online calculator: /

# Hematopoietic Cell Transplantation Specific Comorbidity Index (HCT-CI)
Using the Charlson Comorbidity Index 82 as a template, Sorror et al. re-developed this tool as a prognostic tool to better gauge post-allogeneic transplant survival outcomes -HCT-CI 83 . This index embraces the variables discussed in Section 2. This index has been validated and is independent of disease characteristics. Importantly, the variables that were considered in this model are predominantly physical with little to no evaluation of mental or psychosocial variables. The use of the HCT-CI allows an estimation of the transplant-related mortality (see appendix 1). The following is web link to facilitate score calculations: 

# HCT-CI in Clinical Settings and Comparisons with Other Scoring Systems
The HCT-CI has been evaluated and deemed prognostically useful in a variety of allogeneic transplant settings with modifications to incorporate combinations of age, remission status and performance status  . Further, modifications of the HCT-CI have been used in the autologous setting  . On reviewing our local data on 700 patients who received allogeneic HCT, HCT-CI did not appear to be associated with post-HCT outcomes 94 .
Others have attempted to compare the accuracy of EBMT Score and the HCT-CI. For instance, Michaelis et al., in a single centre retrospective analysis using regression modeling suggest that a modified Pre-Transplant EBMT Risk Score is superior to the HCT-CI Score in predicting overall survival and non-relapse mortality after allogeneic HCT in patients with acute myeloid leukemia 95  patients with ALL within a single European center and suggests that the EBMT risk score may be preferable over the HCT-CI 96 .
The PAM score was compared with the HCT CI at a single institution and suggests the HCT-CI was more predictive of overall survival 93 but the conclusions are inconsistent 97 .
Taken together, there is no clear co-morbidity index that clearly embraces all aspects of recipient and/or disease variables. Moreover, the accuracy of prediction tools is likely dependent on local variables that are either known or unknown. However, it is reasonable to adopt the HCT-CI as the default index as it is the most widely used tool for pre-HCT comorbidity assessment. The routine use of this tool would allow within-center and cross-center outcome comparisons. Moreover, it has been adopted by the CIBMTR.

# Geriatric (Frailty) Assessments
In patients  65 years receiving chemotherapy, geriatric assessment (GA) should be used to identify vulnerabilities that are not routinely captured in oncology assessments. There are many variants of GAs with different domains. In principle, it would include domains of functional status, physical performance and falls, comorbid medical conditions, depression, social activity/support, nutritional status, and cognition.
The comprehensive geriatric assessment (CGA) include domains of functional status, cognitive function, comorbidities & geriatric syndromes, polypharmacy, psychological status, social support and nutritional status and is suggested in the practice guidelines developed by the National Comprehensive Cancer Network 98 as well as ASCO 99 . The use such of such tools are able to predict adverse outcomes (including chemotherapy toxicity and mortality), which can help inform shared discussion making with the patient. The ASCO guidelines 99 

# Integrating Psychosocial Factors
Due to lack of definitive evidence, none of the psychosocial factors discussed above represent absolute contraindications to HCT. However, it needs to be recognized that there is also a lack of safety data for patients who exhibit severe psychiatric illness (e.g. major depression, suicidal ideation/planning, psychotic illness with delusions/hallucinations, etc.), active abuse of alcohol or street drugs, or those who demonstrate profound degrees of non-compliance. Prior to accepting that such patients are eligible to proceed with HCT, they require early referral (ideally at diagnosis of malignancy) to psychology, social work, or psychiatry as appropriate. If the patient does not demonstrate engagement and compliance with psychosocial services, or if psychosocial concerns are not stabilized, transplant may be deferred in order to prioritize patient safety. This would be considered especially when psychosocial factors severely impair functioning and/or adherence to treatment plans, or place the patient at immediate safety risk (e.g., actively psychotic, suicidal, substance dependent, extreme poverty, high degree of family conflict).  Linkage disequilibrium exists and therefore some gene combinations are found together more frequently than is explained by chance alone; some combinations of genes are found together more frequently in populations with different ethnic origins. This can greatly increase or decrease the likelihood of finding a full allelic match. In addition, minor histocompatibility antigens are found outside of the MHC complex that may impact engraftment and graft-versus-host disease (GVHD).
In the past, serologic typing defined antigen groups on lymphocytes using antisera to different antigens in the presence of complement to induce cell death. More recently, DNA technology has changed the face of HLA typing, with >1000 alleles detected. Difficulties arise in knowing which antigens/alleles mediate graft rejection and GVHD, and as testing becomes more specific, the pool of available donors for each patient becomes smaller.
HLA typing in Calgary is now routinely performed by next generation sequencing. 

# Nomenclature
Terminology is standardized through the WHO nomenclature committee: 1 The identifier starts with a hyphen, followed by the name of the gene (for example, A, B, C), an asterisk and at least a four sets of digits separated by colons (i.e. HLA-A*XX:XX:XX:XX). The first set of digits corresponds to the allele group and the second set of digits defines a specific HLA protein. Thus, HLA alleles that differ in these first four digits will differ in the amino acid sequence of the HLA protein. The third set of digits corresponds to differences in the coding sequence that do not lead to a different amino acid sequence (i.e., a synonymous substitution in the coding sequence). The fourth set of digits corresponds to differences in non-coding regions.
Low resolution typing uses probes or a primer that detect all the alleles of an HLA gene to identify a gene group. Intermediate resolution typing identifies multiple but limited alleles, and high resolution provides accurate typing at the allele level.
If the recipient and donor are homozygous at a mismatched locus, this is considered a two-locus mismatch. In addition, if a recipient is homozygous at a locus and the donor is mismatched at that locus, this is considered a mismatch in the rejection direction.

# Selecting an Allogenic Donor: Guiding Concepts
- Donor characteristics associated with improved overall survival are prioritized.
- When available, local data is incorporated into the selection algorithm.
- For patients with high risk disease, time to transplant may influence physician choice of donor.
The donor selection algorithms presented in this chapter are mostly consistent with recently published CIBMTR/NMDP guidelines for selection of unrelated donors, 2 with differences related to local data with respect to CMV matching. - Mismatch at HLA-A, -B, -C or -DR was associated with increased risk of death, grades 2-4 and grades 3-4 aGVHD, cGVHD and treatment-related mortality. - HLA DQB1 and DPB1 mismatches: among 8/8 matched cases, DQB1 mismatches were only associated with grades 2-4 aGVHD (RR1.2) and DPB1 mismatches were associated with grades 2-4 aGVHD (RR 1.4), grades 3-4 aGVHD (RR 1.5), and decreased relapse (RR 0.71). Importantly, DPB1 non-permissive mismatches were associated with a higher risk of death as compared to DPB1 permissive mismatches. There was no difference in survival between those receiving DPB1 permissive mismatch versus those receiving DPB1 matched donors, however DPB1 permissive mismatched donors were associated with an increased risk of grades 2-4 (RR 1.3) and 3-4 aGVHD (RR 1.4) and a lower risk of relapse (RR 0.7) as compared to DPB1 matched donors. These findings with respect to DPB1 replicated those of an earlier study in a less recent cohort of patients receiving primarily bone marrow grafts after conditioning with predominantly TBI-based myeloablative conditioning with only 16% receiving in-vivo T-cell depletion. 3 - In contrast, regarding HLA-DPB1 matching, local data did not demonstrate significant differences in relapse and GVHD outcomes among donor-recipient pairs matched or permissive/non-permissive mismatched at HLA-DPB1 in a small cohort without multivariable adjustment. 4 The local data requires further follow-up in a larger cohort with multivariable modelling.

# HLA-Mismatched Donors

# Unrelated
Importantly, ABMTP data suggests that 7/8 unrelated donor HCT in Alberta is associated with similar overall survival as compared to 8/8 unrelated donor HCT, thus 7/8 unrelated donors are acceptable alternative donor sources when a matched sibling or 8/8 unrelated donor are unavailable. 5 Alternatively, haploidentical related donors are widely and quickly available and excellent outcomes have been reported in the literature using the post-transplant cyclophosphamide platform. Umbilical cord HCT has not been a typical choice for alternative donor HCT for adults in Alberta. Nevertheless, umbilical cord HCT may be pursued in circumstances where proceeding to allo-HCT is felt to be critically important and 7/8 unrelated or haploidentical donors are unavailable.
In both 7/8 unrelated donor HCT and haploidentical HCT, it is critical to identify donor-specific antibodies (DSAs) against the locus/loci of mismatch. DSAs have been strongly associated with graft failure, poor graft function and reduced overall survival. 6  - When comparing locus of HLA mismatch, there were no large differences in outcomes.
- The exception to this was mismatch at HLA-C 03:03/03:04, which was associated with similar survival to 8/8 matched transplants, a finding that replicated that of a previous study. 7 - Among 7/8 donors, no significant effect of mismatch at DQB1 or DPB1 mismatch were observed. This stands in contrast to findings of other studies, i.e. the literature does not provide clear guidance with respect to matching DQB1 and DPB1 in 7/8 matched donors. However, an as of yet unreplicated single study suggests that >2 mismatches of low expression HLA loci (HLA-DP, -DQ, -DRB3/4/5) in 7/8 transplants is associated with increased mortality (HR 1.45), predominantly in the form of treatment-related mortality (HR 1.68). 8

# Haploidentical
Selection of donors for haploidentical HCT has been reviewed by the EBMT along with the publication of consensus recommendations. 9 Overall, the literature regarding haploidentical donor selection with the PTCy platform is sparse as compared to the literature regarding unrelated donor selection. The following haplo HCT donor characteristics have been associated with improved survival in >1 published study: 9 - Younger donor age (particularly less than 40 y.o.).
- Sibling or offspring donor as opposed to parent donor (however, this was not replicated in the large CIBMTR study discussed below). - Avoid major ABO incompatibility only in bone marrow transplantation (no effect of ABO mismatch in peripheral blood stem cell transplant). The following donor characteristics may be associated with improved recipient outcomes but require further verification. These characteristics may be considered if the above donor criteria are met and there remains >1 suitable haploidentical donor choice: 9 - Male donor for male recipient.
- If using a parent donor, father donor preferred over mother. The following donor characteristics have not consistently been shown to affect recipient outcome in haploidentical HCT: 9 - Degree of HLA mismatch. A recent CIBMTR study examined the largest cohort to date (>1400) of haploidentical HCTs transplanted with a PTCy platform and provided significant insight with respect to haploidentical HCT donor selection, particularly with respect to the role of HLA matching. 10 Major findings included:
- Improvement in overall survival was associated with younger donor (particularly age 1 potential donors under age 40, the above calculator may be used to select the donor that will result in the best disease-free survival. If there are no potential donors under age 40 but >1 over age 40, the calculator may be used to select the donor that may result in the best disease-free survival.

# Donor-Specific Anbodies (DSA)
For recipients with potential HLA-mismatched unrelated donors and haploidentical donors, HLA antibody screening will be performed. If HLA antibody screening is positive then Single Antigen Bead analysis will be performed to assess the presence of donor-specific HLA antibodies (HLA-DSA). In recipients positive for HLA-DSA, a T and B cell flow crossmatch will be performed using donor lymphocytes and recipient serum.

# Non-HLA Factors
A retrospective review by the NMDP of 6978 unrelated bone marrow transplants from 1987 to 1999 assessed the impact of donor age, sex, parity, CMV status, ABO incompatibility, and ethnicity on transplant outcomes. 12 Only increasing donor age was associated with decreasing 5-year overall survival, and increased acute grade 3 and chronic GVHD. Overall survival at 5 years was 33% with donors 18-30 years old, 29% with donors 31-45 years old, and 25% if donors were >45 years old (p=0.0002). Multiparous female donors were associated with a higher likelihood of GVHD than male donors (54 versus 44%, p<0.0001) but there was no impact on overall survival.
Two modern studies have confirmed that age is indeed the only non-HLA donor factor that is consistently associated with recipient survival. The first study examined two cohorts of several thousand patients each with the intention of producing a donor selection score: three donor characteristics predicted recipient mortality in the first cohort: CMV mismatch (negative impact for D-R+, HR 1.14), non-permissive DPB1 mismatch (negative impact, HR 1.13) and older donor age (negative impact, HR 1.07 per decade increase in age). In the second cohort, only donor age predicted recipient survival (negative impact, HR 1.11 per decade increase in age). In absolute terms, choosing a donor 2 years older was associated with a 1% decrease in 2 year survival, 5 years older a 2% decrease, 10 years older a 3% decrease and 20 years older a 7% decrease. 13 In a second large study, donor age was the only non-HLA donor factor that was associated with survival. As in the former study, donor age was continuously associated with recipient survival: for every 10 year increment in donor age, there was a 5.5% increase in hazard ratio for overall mortality. 14 CMV serostatus. Selecting a CMV seronegative donor for a CMV seronegative recipient is a commonly accepted practice based on multiple reports of worse survival of seronegative recipients receiving grafts from seropositive donors, 15,16 but this is generally based on studies in which GVHD prophylaxis did not include rabbit ATG (anti-thymocyte globulin). Kalra et al. published the outcomes in 928 Alberta patients who underwent myeloblative HSCT in hematological malignancies between 1999 and 2014 who received ATG as part of the conditioning regimen, and focused on the impact of donor and recipient CMV serostatus on transplant outcomes. 17 In this study, donor CMV serostatus had no impact on recipients who were CMV sero-negative, whereas there was a substantially lower survival in the D -R + patient group versus D + R + (41% vs. 59% at five years, p=0.001). Survival rates were also lower in D -R + HLA-matched sibling transplant recipients compared with D + R + HLA matched unrelated donor transplant recipients (44% vs. 66%) at 5 years, p=0.009). The differences in survival were being attributed to higher non-relapse mortality. The conclusion from this study was that, when using ATG for patients with malignancies, choosing a CMV seropositive donor for a CMV seropositive recipient is important, even if this requires an unrelated graft. In an updated analysis, the difference in survival between the the D -R + group versus D + R + group appeared to be limited to those with lymphoid malignancies. 5 Thus, CMV matching for R + recipients need only be considered for those undergoing allo-HCT for lymphoid malignancies.
Thus after matching for factors that influence recipient survival: HLA-A, -B, -C and -DR matching, CMV serostatus in those with lymphoid malignancies, younger age of donor, avoidance of HLA-DPB1 non-permissive mismatching, and other less important factors (eg, gender, ABO compatibility, donor size, in no particular order) can be considered.

# Syngeneic Donors
There is no need for GVHD prophylaxis. These transplants are associated with a higher relapse rate compared to matched sibling transplants in malignancies where a graft-versus-leukemia effect is important; such as acute myeloid leukemia (AML) (52 versus 16%), CML (40 versus 7%), and acute lymphoblastic leukemia (ALL) (36 versus 26% at 3 years). 11 No graft-versus-lymphoma effect has been seen in non-Hodgkin lymphoma syngeneic versus allogeneic registry data, and syngeneic transplant may be a good option for lymphomas or benign disorders.

# Donor Eligibility and Suitability
According to the Health Canada lymphohematopoetic cells for transplant standards manual, the following donors are not suitable for peripheral blood stem cell or bone marrow donation: -persons with prion-related disease -persons with a potentially transmittable neurological disease of an unestablished etiology -persons with active encephalitis or meningitis of infectious or unknown etiology -persons with rabies or persons who, within the past 6 months, were bitten by an animal and treated as if the animal was rabid -persons with a history of infection with HIV, clinically active HCV or HBV -persons with a family hx of Creutzfeldt-Jakob disease -persons who have received human-derived pituitary growth hormone -persons who have received dura matter -persons with HTLV-I or HTLV-II, active WNV, or syphilis -persons who have known or suspected sepsis at the time of donation -persons previously diagnosed with a hematologic malignancy or with melanoma -persons previously diagnosed with other types of cancer, unless they have been evaluated and deemed suitable to donate by a physician Further, the WMDA Donor Medical Suitability Wiki can be used as a resource regarding further suitability issues, particularly with respect to donor medical conditions. This can be found on WMDA's website at +Donor+Medical+Suitability+Recommendations+Main + page Finally, potential donors may screen positive on the ABMTP Donor Personal History Questionnaire (for example, related to travel, habits, sexual history etc.). In the case of a positive screen, donor clearance will be at the donor physician's discretion. If a clinically relevant risk of disease transmission is identified, an exceptional release may be requested by the donor physician in case of urgent medical need. Further guidance with respect to positive screens on the ABMTP Donor Personal History Questionnaire and their implications are found in the Donor Personal History Questionnaire Guidance Document found here: costs relative to traditional bone marrow harvests  . Chemotherapy (a salvage regimen or cyclophosphamide 2-4g/m 2 ) plus G-CSF 5-10 mcg/kg/day is an acceptable standard method of stem cell mobilization  . Predictors of poor mobilization include: advancing age, prior treatment with chlorambucil, fludarabine, melphalan, radiotherapy to >25% of bone marrow, or repeated cycles of chemotherapy plus G-CSF within the past 6 months, as well as those with low blood platelet counts prior to mobilization treatment, or those who have experienced prior failure of stem cell mobilization.
Registry (CIBMTR and EBMT) data suggest there may be a role for purging based on the extremely low relapse rates following syngeneic SCT, followed by higher relapse rates with purged autologous SCT and then significantly higher relapse rates with unpurged autologous SCT 20 . This data, however, is potentially biased, and randomized controlled trials evaluating ex-vivo autograft tumor purging techniques have not been reported in the setting of autologous transplantation for lymphoma. In addition, autograft purging results in stem cell loss and delays hematopoietic and immunological engraftment  . Because of these facts, routine ex-vivo autograft purging is not recommended.

# Option 1. Granulocyte Colony Stimulating Factor (G-CSF) Only
Indications:
- Mobilization of peripheral blood stem cells for autologous stem cell transplant patients who have not had prior chemotherapy or radiotherapy.

# G-CSF dosing -autologous donor:
- G-CSF 5-10 g/kg/day for 4 days, rounded to nearest vial size and fewest injections (see Table 1).

# Option 2. Combined Chemotherapy and G-CSF Stem Cell Mobilization
Indications:
- Mobilization of peripheral blood stem cells for autologous stem cell transplant patients who have had prior chemotherapy or radiotherapy.

# Standard intensity regimen indications:
- Myeloma - Germ cell tumours - Lymphoma with largest tumour mass less than 5 cm and negative marrow biopsies 

# High intensity regimen indications:
- Lymphoma with mass greater than 5 cm, bone marrow involvement, or refractory disease

# High intensity regimen example:

# G-CSF dosing:
- Patients without risk factors for poor mobilization should receive G-CSF 5-10 g/kg/day, rounded to nearest vial size and fewest injections, beginning on the day indicated in the protocol and continuing until completion of apheresis (see Table 1) Plerixafor use should be considered in the following settings:
- Preemptively for patients predicted to mobilize poorly based on the risk factors above. It should be used in combination with G-CSF with or without chemotherapy. 2. For salvage immediately prior to apheresis for patients with suboptimal mobilization. Plerixafor should be given if the post nadir WBC count is >5 x 10 9 /L and CD34 count is >5 but <20 x 10 6 /L or if <50% of the target CD34 yield was achieved on the first day of apheresis. 3. Re-mobilization for patients with a prior failed attempt at mobilization with G-CSF with or without chemotherapy.

# Plerixafor dosing:
- The recommended dose of Plerixafor is 0.24 mg/kg body weight (0.16 mg/kg for creatinine clearance <50 mL/min) by subcutaneous injection, injection with the dose capped at 24mg, given the day before apheresis is planned, and then daily until apheresis is complete.

# Apheresis:

# Mobilization and Collection for CD34 Enriched Autologous Transplants
For patients requiring CD34 enriched autologous stem cell products, such as those undergoing ASCT for autoimmune disease, CD34 collection targets will be higher in order to compensate for losses during processing and to obtain a final product containing 5 x 10 6 CD34 cells. This target is to be collected on a single day of apheresis to avoid needing more than one day of CD34 selection. Based on these requirements, the following collection parameters are recommended:
- Requested CD34 cell dose for collection will be set at 8  

# Additional doses of G-CSF for allogeneic donors:
- Order additional doses of G-CSF to be administered after collection and the following morning if fewer than 3 x 10 6 CD34+ cells/kg were collected in the first apheresis session.

# Apheresis:
- Plan large volume apheresis (3 blood volumes) on day 5 using peripheral venous access. A second collection day may be required if the minimum dose is not reached on one day of apheresis. - Minimum of 8L apheresis - Target CD34+ Collection: 5 -10 x 10 6 /kg recipient weight - Minimum target: 3 x 10 6 CD34+ cells/kg recipient weight

# Failed Mobilization of an Allogeneic Donor
Failure to collect a sufficient number of stem cells to transplant an allogeneic recipient has very significant implications for that recipient. Options for the transplant center include approaching a backup donor or approaching an alternative family member for haploidentical donation; in most cases, however, the recipient has already been conditioned and approaching a second donor may 6 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: July 7, 2021 Effective: April 26, 2021 result in significant delays and prolonged aplasia. In Alberta, if a related donor mobilizes poorly (blood CD34 count 5-10 per microliter) after five days of G-CSF they will be offered a dose of plerixafor off label and will undergo collection by apheresis on day 6 if CD34 count increases to > 15. Donors who decline to receive plerixafor or whose blood CD34 count is < 5 per microliter on the fifth day of G-CSF will be asked to undergo surgical bone marrow harvest urgently on day 6. In the case of unrelated donors, early notification of the transplant center is essential; the CBS Stem Cell Registry has advised that plerixafor should not be administered to unrelated donors.

# Cytokine-Stimulated Bone Marrow
The use of G-CSF stimulated bone marrow for hematopoietic cell transplantation was proposed as a way of providing a product with the rapid engraftment potential of G-CSF mobilized peripheral blood grafts but with the low risk of GVHD associated with bone marrow. Studies have shown that GVHD rates are lower with bone marrow (including G-CSF stimulated marrow) but no consistent advantage of G-CSF stimulated marrow over unstimulated marrow has been demonstrated either in terms of overall-or progression-free survival 24 . The ABMTP will not routinely administer G-CSF to bone marrow donors.

# Donors from Vulnerable Groups
Minor Donors: <18 years of age may be selected if:
a. There is no equivalent histocompatible adult donor who is willing and readily available for donation b. It is deemed the recipient will benefit from transplantation c. The clinical, emotional and psychological risks to the donor are minimized and are reasonable in relation to the benefits expected to the donor and the recipient as outlined in the pediatric donor eligibility and suitability evaluation SOP (BMTS20005) d. Following a psychological evaluation, the staff has deemed that there is a strong personal and emotionally positive relationship between the donor and recipient as outlined in the Pediatric Donor Eligibility and Suitability Evaluation SOP (BMTS20005) e. Parental permission/consent and child assent will be obtained as per Pediatric Blood and Marrow Transplant Consent Procedure (BMTS20009) f.
A donor advocate trained in pediatrics will be assigned as outlined in the Pediatric Donor Eligibility and Suitability Evaluation SOP (BMTS20005) g. The donor must weigh a sufficient amount to safely undergo collection  Resources will be provided for disabilities, including the visual or hearing impairments g. Donors may access a third party advocate as they feel appropriate as per "Interaction Between Alberta Health Services and Third Party Advocates PRR-04"

# Repeat Donations
The Alberta BMT Program permits donors to donate on more than one occasion, provided the risk of donating is justified by the condition of the recipient. Donors will only be permitted to donate stem cells (bone marrow and/or G-CSF stimulated peripheral blood stem cells) twice, although the program will not limit the number of donations of non-mobilized cells such as donor lymphocyte infusions.

# Weekend Apheresis
If a Weekend Apheresis Collection is probable or confirmed, the most responsible physician shall contact personnel in Flow Cytometry, Apheresis and Cellular Therapy Laboratory by Friday at noon. 

# Use of G-CSF Biosimilars
Biosimilars are approved biologics with comparable quality, safety, and efficacy to a reference product for which patent protection has expired. Biosmilar regulatory approval is provided on the basis of a robust comparability exercise demonstrating similarity with the original product, rather than on the need to show a positive risk-benefit assessment, which it is assumed has already been proven. The degree of clinical similarity required to achieve biosimilar status is considered on a case-by case basis by the regulatory authorities.
Biosimilars of G-CSF, based on the original filgrastim product Neupogen, have been available for a number of years and are now widely used, often exceeding the use of the original product. For the currently approved biosimilar G-CSFs (e.g. Grastofil), extrapolation to all indications of the reference product has been granted, given the comparable receptor site kinetics and mode of action. This includes mobilization of peripheral blood stem cells in patients undergoing autologous stem cell transplantation as well as for stem cell mobilization in patients and healthy donors.
For autologous stem cell mobilization, the overall effectiveness of biosimilar G-CSF has been evaluated in several open-label studies, some of which have include the reference product as a comparator. All of these studies have shown no significant differences in efficacy (e.g. collected, number of G-CSF injections required, apheresis days, etc.), and safety, with similar incidence and severity of common adverse events such as bone or muscles pain and headache, and no severe or unexpected AEs  . There are a few reports of biosimilar G-CSF use for PBSC mobilization in healthy donors that suggest these agents are effective and well tolerated, with similar mobilization outcomes in comparison to Neupogen, with no clinically significant differences between groups  .
There is an ongoing long-term safety study over 10 years, which will contribute data for up to 2000 person-years and add to the cumulative assessment of the long-term safety of G-CSF as a mobilizing agent 31 .
The safety considerations for healthy donors differ from those for patients, since donors do not benefit from the treatment. The safety threshold for donors is therefore extremely low, and until more efficacy and safety data have been collected, OneMatch has recommended against the use of biosimilar G-CSFs in healthy donors at this time. 

# COVID-19 Vaccines and HCT Recipients
Both allo-and auto-HCT recipients experience poor outcomes after COVID-19 infection. 7 COVID-19 vaccines are now licensed and available in Canada. Existing COVID-19 vaccines are non-live and utilize either an mRNA or a replication-incompetent adenovirus vector platform. Although there are few studies on COVID-19 vaccination in HCT recipients, the benefits of vaccination are likely to outweigh the potential harms in HCT recipients. Accordingly, national and international HCT groups have endorsed COVID-19 vaccination for auto-and allo-HCT recipients. Thus:
- In Alberta, HCT recipients will be vaccinated for COVID-19 when criteria for other non-live vaccinations, as outlined above, are met. Additionally, because a single dose of a COVID-19 vaccine appears to be poorly immunogenic in those with immune deficiency and because a second dose at a 3 to 4-week interval appears to markedly improve immunogenicity in these individuals, vaccination at intervals specified by the manufacturer/label (i.e. 3-4 weeks for 2 dose vaccines) should be pursued for HCT recipients rather than the extended intervals being used in the Alberta general population. 8,9 A third dose 8 weeks after dose #2 will complete the primary vaccine series for COVID-19 and a booster (fourth) dose will be given at 5 months after the third dose. 

# Vaccination after CAR-T Cell Therapies
Developing recommendations for vaccination after CAR-T therapies is challenging because:
- There are no studies detailing the immunogenicity, efficacy or safety of vaccination after CAR-T therapy. - There are a lack of consensus guidelines and limited expert opinion.
- Patients have received varying pre-CAR-T therapies that will affect post-CAR-T risk of infection as well as immunogenicity, efficacy and safety of vaccines (i.e. allogeneic-HCT vs. autologous-HCT vs no HCT before CAR-T cell therapy). - Patients will receive varying post-CAR-T therapies that will affect risk of infection as well as immunogenicity, efficacy and safety of vaccines (i.e. no therapy vs. allogeneic-HCT). - Varying CAR-T cell constructs/targets (i.e. CD19 vs. BCMA vs. others) will lead to varying quantity/quality of immunodeficiency and varying paces of immune reconstitution. Relevant but limited data are available for CD19 CAR-T therapies and no data are available for other constructs/targets. - Specifically after CD19 CAR-T therapy, nearly all responding patients will rapidly develop Bcell aplasia which may persist >1 year post-therapy. However, ~50% of recipients will experience B-cell recovery beginning at 6-12 months post-therapy. 10 - Despite B-cell aplasia, pre-existing humoral immunity to vaccine-related antigens may be preserved in CD19 CAR-T recipients due to the persistence of CD19 negative plasma cells. 11 Thus, recognizing the major limitations as outlined above, recommendations for CAR-T recipients in Alberta include:
- For those who received allo or auto HCT prior to CAR-T cell therapy and post-HCT vaccinations were not initiated or were interrupted, the standard post-HCT vaccination series will be restarted from the beginning. - For all others, vaccination against Influenza and COVID-19 beginning at 6 months post CAR-T therapy (these vaccines may begin at 3 months post CAR-T at physician discretion) post as per non-live vaccine clearance criteria for HCT recipients. - Measure tetanus antibody, Hep B surface antibody, rubella antibody and measles antibody at 6 months and 24 months post CAR-T cells to monitor immune reconstitution, with no action required for abnormal results. - No further recommendations for vaccination can be made. These guidelines will be updated as the post-CAR-T cell vaccination literature grows. from production of isohemagglutinins by lymphocytes infused with the graft. ABO antigens are the primary concern in graft compatibility, though non-ABO antigens such as Rh and Kidd have been reported to cause post-transplant hemolysis 5,6 . 

# Consequences of ABO Incompatible Transplant
The relative importance and discordant consequences of ABO incompatible transplants (as described below) is dependent on the era of transplants, underlying disease, type of transplants (Haploidentical, Cord), graft source (marrow, PBSC etc.), conditioning (e.g. reduced intensity) as well as the availability of superior supportive measures.
Historically, there have been a number of single center reports as well as four large registry reports 2,7-9 describing the impact of ABO incompatibility on transplant outcomes. Overall, the results are inconsistent though some show a negative effect on neutrophil engraftment 2,7 , acute graft versus host disease 2,7 , non-relapse mortality 2,8 , and overall survival 2,8 . Moreover, an individual patient data-based meta-analysis conducted in 2009 suggests that there is no adverse association between any ABO mismatching and survival 10 . 

# Acute Hemolytic Reaction
Acute hemolytic reactions occur in 15% of transplants with major ABO incompatibility 11 , and in almost half of those receiving a high volume (>50mL) of incompatible red cells 12 resulting in renal failure and even death in some patients. Transplants with minor ABO compatibility will rarely cause acute hemolysis from the transfusion of donor isoagglutinins against recipient red cells.
Delayed Red Cell Engraftment and Pure Red Cell Aplasia (PRCA) Recipient antibodies directed against donor red cells (isoagglutinins) are usually cleared rapidly following transplant, with the only consequence being a slight increase in transfusion requirements compared to ABO compatible grafts 13 . Isoagglutinins disappear more rapidly following unrelated donor compared to related donor transplants 1,14 , and in those with graft versus host disease 1,15 , and more slowly following non-myeloablative transplant 16 . Persistent anti-donor red cell isoagglutinins can cause delayed red cell engraftment that may persist for months or even years following transplant. In some cases, bone marrow biopsy will show normal erythroid precursors up to the point of expression of the incompatible antigen, with absence of precursors beyond that point reflecting the expression of ABO antigens at different stages of red cell development 17 . There is an increase in transfusion requirements contributing to iron overload.

# Delayed Transfusion Reaction
Infusion of grafts with minor ABO incompatibility has rarely resulted in a delayed transfusion reaction, thought to be due to production of anti-host red cell antibodies by donor B-cells infused with the graft. These have mostly occurred 7-10 days after the transplant in red cell group A recipients of group O grafts 18 . Almost all patients had GVHD prophylaxis consisting of cyclosporine without methotrexate.

# Neutrophil and Platelet Engraftment
It is not clear if ABO incompatibility can affect neutrophil and platelet engraftment, or contribute to graft failure. Major incompatibility was associated with delayed neutrophil engraftment in 3 registry studies 2,7,19 . but was not observed in several other studies, including a recent large CIBMTR/NMDP evaluation of donor characteristics 8,9, . Even if there is a difference, a median 1-2-day delay in engraftment is not likely to be clinically relevant. One registry study suggests delayed platelet recovery with major incompatible grafts 2 . Some single center studies have reported both platelet and neutrophil engraftment issues, but the majority of studies find no impact of incompatibility 18 . A significantly higher rate of graft failure was reported in major or bidirectional incompatible transplants (6/83 vs 0/141 compatible transplants) 24 , though one or more HLA mismatches was also present in 3 of the 6 cases. Two small series also suggested a risk of graft failure that was not seen in a number of other reports 18 

# Graft Versus Host Disease (GVHD)
Red blood cell membranes are rich in proteins of great structural diversity. Polymorphisms of these antigens, incompatible ABO antigens, and allelic variations of ABO antigens could serve as minor histocompatibility antigens influencing rates of GVHD. Expression of similar antigens on endothelial and epithelial tissues could serve targets for the donor immune system, inciting a GVH response.

# Acute GVHD
Increased rates of grade II-IV aGVHD were reported in two cohort studies 25,26 as well as two registry studies 2, 7 , but were not seen in most other reports 18,23, .
Interesting, bi-directional mismatching (but not major mismatch) was associated with increased risk of grade II-IV acute graft-versus-host disease in a recent EBMT registry study evaluating leukemia patients undergoing haplo-identical transplants with a HR 2.387; 95% CI: 1.22-4.66; P=0.01 19 . However, the same authors note that patients with minor mismatching transplanted with bone marrow grafts experienced increased grade II-IV acute graft-versus-host disease rates (HR 2.03; 95% CI: 1.00-4.10; P=0.04) 19 . In contrast, the effect of ABO mismatch on transplant outcomes and transfusion requirements in 594 patients undergoing reduced-intensity conditioned (RIC) HSCT with alemtuzumab was evaluated in three UK transplant centres and did not demonstrate any association with aGVHD risk 31 . Further, a registry study from CIBMTR evaluating 1,013 AML patients who underwent MMURD transplantation between 2005 and 2014 suggest that the incidence of grade II-IV acute graft versus host disease was marginally lower in patients with major ABO mismatching (HR 0.7, 95% CI, 0.5-1; P = .049) 21 . In the absence of clear biologic plausibility and conflicting evidence, such positive associations maybe due to chance.

# Chronic GVHD
There are minimal studies that link chronic GVHD with ABO incompatibility. In the before mentioned UK study, the incidence of extensive chronic GVHD was higher in patients with minor and major mismatch compared with those who were ABO matched (hazard ratio (HR) 1.74, P=0.032 for minor, HR 1.69 P=0.0036 for major mismatch) 31 .

# Relapse, Non-Relapse Mortality, and Survival
There is little evidence to suggest an influence of ABO incompatibility on relapse. None of the four registry studies found this association. One case series reported a decrease in relapse when minor or bidirectional incompatible grafts were used compared to major incompatible or ABO matched grafts on univariate analysis, but this association was not significant on multivariate analysis 32 . By contrast, cohort and registry studies have found an increase in NRM and decrease in overall survival 2,8,18,33,34 , though these findings were not confirmed by other studies 7, 20-23, 27-29, 31, 35 .
More recently, Kollman et al 20 . re-examined the association of donor characteristics associated with post-HSCT outcomes in the modern HSCT era using data from CIBMTR/NMDP. where the mortality risks associated with minor and major ABO mismatched transplants were HR, 1.09 (95%CI, 0.98-1.23) and HR 1.09 (95% CI, 0.91-1.21) respectively. They also considered the effect of ABO match separately for bone marrow and peripheral grafts and did not see a significant effect of ABO mismatching on overall mortality. Further, ABO compatibility was not associated with NRM, Relapse Mortality, acute or chronic GVHD.
Similarly, the EBMT evaluated the influence of ABO compatibility in 837 patients who underwent haploidentical transplantation and did demonstrate differences in Non-relapse mortality, relapse incidence, leukemia-free survival, overall survival, and chronic graft-versus-host disease rates between ABO-matched and -mismatched patients. However, patients with major ABO mismatching and bone marrow grafts had decreased survival (HR=1.82; CI 95%: 1.048 -3.18; P=0.033). This finding was not observed in a CIBMTR study evaluating the impact of ABO mismatch on transplant outcomes with various graft types 22 .
In contrast, the Chinese developed a risk score utilizing data from 1199 consecutive subjects receiving transplants from an HLA-haplotype-matched relative using granulocyte colony-stimulating factor and anti-thymocyte globulin (n=685) or an HLA-identical sibling (n=514). They suggest that ABO mismatch was 1 of 3 (others were older donor/recipient age, female-to-male transplants) independent risk factors that conferred risk of TRM and LFS 36 .

# Summary
An ABO compatible donor is preferred over ABO incompatible donor, but priority is given to HLA matching, donor age. The relative importance of ABO compatibility over CMV status and female gender/parity is less clear with respect to post-HSCT outcomes 37 .

# Management
The red cell content of graft is partially depending on whether the graft is from bone marrow or peripheral blood collection by apheresis. In the later, the red cell content is normally <10ml per collection while is higher and more variable with bone marrow.
The safe volume of transfused incompatible red cells has not been established in large studies. In one case series, sixteen of 36 patients receiving over 50 mL of incompatible red cells experienced signs or symptoms of an acute hemolytic reaction, 10 had renal failure, and 6 died, compared to no deaths, no renal failure, and only 3 hemolytic reactions in 12 patients transfused less than 50 mLs 12  minimal toxicity. The risk of acute hemolytic reactions can be reduced by decreasing the 1) red cell content of the graft, or 2) the isoagglutinin titers of the recipient.
Red cell depletion of the HPC product can reduce the total nucleated cell count 38 . It has been suggested that this may be of importance if the HPC content is low or if additional cells are not readily available, as with cord blood units or volunteer unrelated donor grafts 39 . In addition, because unrelated donor HPC products can come from anywhere in the world, and prolonged intervals between collection and infusion into the recipient are associated with decreased likelihood of engraftment and increased mortality 40 , further product manipulation in these circumstances could be undesirable.
An alternative approach to red cell depletion is to consider isohemagglutinin reduction by plasma exchange for major ABO-incompatible bone marrow grafts. Sheppard et. al report their single centre experience suggests that engraftment times, transfusion requirements, incidence and severity of graft-versus-host disease, and 100-day treatment-related mortality did not differ between the patients with a major ABO donor mismatch and those with an ABO-compatible donor. Further, no hemolytic transfusion reactions were observed during product infusion. 41 This approach has been counter-challenged 42 as antibody titering is a laboratory technique shown to be difficult to standardize across institutions 43,44 . Therefore, it may be difficult to determine whether a concentration of incompatible antibody can be universally considered to be protective against a hemolytic reaction.

# The Calgary Approach
In Calgary, the Alberta Bone Marrow Transplant Program (ABMTP) work-up obtains donor and recipient blood type information prior to selection of suitable donor for transplant. The transplant physician reviews the donor and recipient blood type information and is responsible for determining compatibility and indicating on the order for stem cell collection the compatibility status of the donor product. Compatibility is determined based on Table 25-1 in AABB Technical Manual (Table 1 above). The Cellular Therapy Laboratory will determine the product compatibility at the time of receipt of a cellular therapy product. If there is major incompatibility, the red cell volume is then determined (SOP: CTL.725 Preparing Cellular Therapy Products for Infusion or Processing).
- For pediatric recipients, the accepted range for ABO incompatible blood volume transfused is 0.2 -0.5 mL/kg. The transplant physician will be contacted with the volume and will direct CTL on desired final RBC content per infusion bag (based on hydration status and renal function of the recipient). CTL will aliquot and/or red cell reduce product as necessary. 2. For adult recipients, less than or equal to 30 mL +/-1 mL of incompatible red cells will be allowed per infusion bag of apheresis product (HPC(A)). If product contains greater than 31 mL of incompatible red cells the product will be split into aliquots. HPC(M) will be red cell reduced to achieve < 30 mL/infusion aliquot. If the initial incompatible red cell volume is < 30mL, no further action is taken.
- For products with very large volumes of red cells, where dividing into aliquots is not practical, red cell reduction by centrifugation, Hespan, or apheresis can be considered.
- For plasma incompatible transplants (minor incompatibility), no action is taken for any recipient as it has been determined by CTL validation studies that there is no association with adverse infusion reactions and minor incompatibility of products.
Following transplants with minor ABO incompatible grafts, the appropriate red cell type to be transfused cannot be determined by the usual blood bank techniques. Blood bank is notified about these transplants in order to provide appropriate blood product support (see Table 2). 3 There is little evidence to guide the management of pure red cell aplasia (PRCA) beyond transfusion support until red cell engraftment occurs. There have been case reports of improvement following administration of erythropoietin  , though this was unsuccessful in other reports 16,48 . There are also case reports of successful treatment of PRCA with rituximab 49,50 , plasma exchange 48,49 , anti-thymocyte globulin  , bortezomib 54 and donor lymphocyte infusion 55,56 . There is insufficient evidence to support the routine use of these treatments for PRCA following ABO incompatible transplant.
There is a suggestion that methotrexate based GVHD prophylactic regimens will result in fewer cases of delayed transfusion reactions. However, given that this is so rare, its clinical impact is negligible compared to that of GVHD. The choice of GVHD regimen should therefore reflect optimal management/prevention of graft versus host disease.  

# Summary

# Frequency of Follow-Up
- The recommended follow-up interval for allo-HCT recipients between day 80 and 1 year post-HCT is every 4-6 weeks. - Long-term follow-up visits for allo-HCT recipients should be at least annually.

# Cardiovascular Disease
- All patients should be counselled with respect to lifestyle modifications that reduce the risk of cardiac events, such as tobacco avoidance, adequate physical activity, maintaining a healthy weight and a healthy diet. factors in addition to anthracycline exposure, including younger age at anthracycline exposure, female sex, chest radiation, hypertension or diabetes).

# Bone Health
- All patients should be counselled regarding lifestyle modifications for bone health including calcium intake 1200 mg/day from all sources, vitamin D 1000 IU/day, smoking cessation, limiting alcohol use & regular weight-bearing exercise. - At 1 year post-HCT or at the onset of cGVHD requiring systemic therapy (whichever occurs earlier), patients should have an assessment of BMD by dual X-ray absorptiometry (DXA) and subsequently a 10 year probability of fracture calculated with the FRAX clinical assessment tool (/) (except patients with multiple myeloma who are already being treated with bisphosphonates). - For those who are no longer on immunosuppression at 1 year post-HCT, the Alberta Toward Optimized Practice (TOP) guidelines for osteoporosis () should be followed. - For those who remain on immunosuppression at 1 year post-HCT, therapy should be offered to: 1) those with established osteoporosis (BMD T-score  -2.5) or history of fragility fracture, and 2) those with a moderate to high probability of fracture by FRAX as outlined by the Alberta TOP guidelines (>10% probability). - In those who remain on chronic glucocorticoid therapy (prednisone equivalent dose >5mg/day) beyond 1 year post-HCT and who do not initiate therapy, annual DXA measurement should be considered. - For those who initiate therapy, repeat DXA should be obtained at 3-5 years on therapy.
- First line therapy is typically with oral bisphosphonates. If identified, treatment of hypogonadism also could be considered in men and pre-menopausal women (after evaluation and discussion of risks/benefits of hormone replacement). Referral to an endocrinologist may be considered for alternate or second-line therapy options. - The need for ongoing bisphosphonate therapy should be reassessed at the end of immunosuppressive therapy and/or at 5 years on therapy. - In those with osteoporosis, a workup for secondary or contributing causes should be undertaken (for example, hypogonadism, hyperthyroidism & hyperparathyroidism).

# Subsequent Malignancy Screening
- All patients should be counselled regarding smoking cessation and cutaneous solar protection.
- All patients should have a yearly history and physical exam that includes oral cavity, thyroid, genitals, breast exam for females, and a complete skin exam. - All patients should visit their dentist for oral/dental examination and cleaning; at least yearly for most patients and every 6 months for those with oral chronic GVHD. after radiation exposure, whichever occurs later but no later than age 40.
- HCT recipients who have received radiation within a particular field, for example chest and those with familial cancer syndromes will require an individualized plan for malignancy screening. - There are no proven screening measures for t-MN after auto-HCT; yearly CBC with early workup of cytopenias for up to 10 years post-transplant may be considered.

# Renal Disease
- All HCT recipients should have at least yearly monitoring of creatinine.
- Allo-HCT recipients should a spot urine albumin/creatinine ratio yearly.
- All patients should have at least yearly blood pressure evaluation and treatment per Canadian (CHEP) guidelines (essentially target BP <140/90 for most patients). - Basic medical management of CKD includes initiation of an ACE inhibitor or ARB for proteinuria, tight glycemic control for diabetics, aggressive management of cardiovascular risk factors and avoidance of nephrotoxins.
- Referral to a nephrologist should be considered when estimated GFR is <30 mL/min, for management of CKD with proteinuria or for workup of CKD of unknown etiology.

# Pulmonary Disease
- The approach to prevention of late pulmonary infections are outlined in the bacterial/pneumocystis prophylaxis, fungal prophylaxis and vaccination chapters of these guidelines. - For autologous-HCT recipients: PFT at 6 weeks post-HCT for those who received potentially pulmonary toxic conditioning. For all, at least yearly history and physical exam for signs and symptoms of pulmonary disease is recommended. - For allogeneic-HCT recipients: routine PFTs for all patients every 3 months for the first year post-HCT followed by yearly PFTs until 5 years post-HCT. For those with active cGVHD beyond 1 year post-HCT, continued every 3 month PFTs should be strongly considered. History and physical exam should accompany PFTs. - Abnormal PFTs or new respiratory symptoms should be worked up promptly with CXR +/-NP swab and sputum culture. For clinical presentations that are not consistent with upper respiratory tract infection or community-acquired pneumonia, CT chest and referral to the BMT pulmonary clinic are suggested.

# Endocrine Disease
- Yearly thyroid examination and TSH measurement for all HCT recipients. - A slow terminal taper of corticosteroids is required for those receiving prolonged courses (>3 weeks) for treatment of GVHD. - A high index of clinical suspicion for adrenal insufficiency should be maintained when tapering patients from prolonged courses of corticosteroids. - Management of diabetes and hyperlipidemia within the context of global cardiovascular risk as outlined in the "Cardiovascular disease" section. - Workup and management of gonadal dysfunction and infertility as published 1,2 .

# Chronic Pain
- HCT recipients with chronic pain should be managed within a multi-disciplinary team that includes HCT providers, pharmacists and the psychosocial team within the Alberta Blood and Marrow Transplant Program with low threshold for referral to the palliative care team at the Tom Baker Cancer Centre.

# Transfusion
- Red cell and platelet transfusion thresholds should be individualized based on clinical circumstances. - The appropriate blood-group products for transfusion after ABO-incompatible allo-HCT per the "ABO Incompatibility" chapter. - For allo-HCT recipients: irradiated blood products should be used from start of conditioning until the later of: 1 year post-HCT, end/"burn out" of chronic GVHD or discontinuation of immunosuppression. - For auto-HCT recipients: irradiated blood products for 7 days prior to stem cell collection and from start of conditioning until 3 months post-HCT, or 6 months post-HCT if TBI was part of conditioning. - All auto-and allo-HCT recipients should receive standard leukoreduced ("CMV safe") blood products. - Transitioning from Pediatric to Adult Post-HCT Care - Survivors of pediatric HCT are typically followed into adulthood and indefinitely in the Alberta Children's Hospital long-term follow-up/survivorship clinic.

# Mental Health
- Long-term follow up visits should include screening for mental health concerns. If concerns are identified, patients should be referred to mental health providers and/or community resources as appropriate.
Last Revised: September 14, 2021 Effective: September 14, 2021
Recommendations:
- All patients should be counselled regarding lifestyle modifications for bone health including calcium intake 1200 mg/day from all sources, vitamin D 1000 IU/day, smoking cessation, limiting alcohol use & regular weight-bearing exercise. - At 1 year post-HCT or at the onset of cGVHD requiring systemic therapy (whichever occurs earlier), patients should have an assessment of BMD by dual X-ray absorptiometry (DXA) and subsequently a 10 year probability of fracture calculated with the FRAX clinical assessment tool (/) (except patients with multiple myeloma who are already being treated with bisphosphonates). - For those who are no longer on immunosuppression at 1 year post-HCT, the Alberta Toward Optimized Practice (TOP) guidelines for osteoporosis () should be followed. - For those who remain on immunosuppression at 1 year post-HCT, therapy should be offered to: o those with established osteoporosis (BMD T-score  -2.5) or history of fragility fracture, and o those with a moderate to high probability of fracture by FRAX as outlined by the Alberta TOP guidelines (>10% probability). - In those who remain on chronic glucocorticoid therapy (prednisone equivalent dose >5mg/day) beyond 1 year post-HCT and who do not initiate therapy, annual DXA measurement should be considered. - For those who initiate therapy, repeat DXA should be obtained at 3-5 years on therapy.
- First line therapy is typically with oral bisphosphonates. If identified, treatment of hypogonadism also be could be considered in men and pre-menopausal women (after evaluation and discussion of risks/benefits of hormone replacement). Referral to an endocrinologist may be considered for alternate or second-line therapy options. - The need for ongoing bisphosphonate therapy should be reassessed at the end of immunosuppressive therapy and/or at 5 years on therapy. - In those with osteoporosis, a workup for secondary or contributing causes should be undertaken (for example, hypogonadism, hyperthyroidism & hyperparathyroidism).

# Subsequent Malignancy Screening
Both auto-and allo-HCT recipients are at increased risk of secondary solid tumours. The risk of secondary solid tumours increases over time post-HCT with a cumulative incidence of about 15% at 25 years post-HCT-a two to three fold increased risk versus age and sex matched controls. 20,21 HCT recipients are particularly at risk (standardized incidence ratio >1) of the following malignancies: all skin including melanoma, thyroid, oropharyngeal, esophageal, liver, bone, central nervous system and connective tissue. 22 Chronic GVHD and duration of immunosuppression > 2 years are major risk factors for skin, oropharyngeal, cervical and esophageal cancers, while conditioning with total body 9 www.ahs.ca/guru BMT Standard Practice Manual Last Revised: September 14, 2021 Effective: September 14, 2021 irradiation (TBI), particularly myeloablative TBI, is a risk factor for skin, thyroid, liver and breast cancers. 22 There is little data to guide second malignancy screening practices in HCT survivors: expert recommendations generally suggest screening similar to the general population with some additions as will be described below. 22,23 Those who have received radiation within specific fields, such as chest or cranial, or those with a cancer predisposition syndrome (ex. Fanconi anemia) may require individualized enhanced screening measures.
Survivors of autologous-HCT are at risk of therapy-related myeloid neoplasms (t-MN) (predominantly myelodysplatic syndrome and AML). The cumulative incidence of t-MN is about 7% at 15 years post auto-HCT. 20 Major risk factors for t-MN are alkylator therapy (5-7 year latency from HCT) and topoisomerase II inhibitor therapy (6 month-5 year latency from HCT). 20 Unfortunately, outcomes of those who develop t-MN is poor. 24 

# Recommendations:
- All patients should be counselled regarding smoking cessation and cutaneous solar protection.
- All patients should have a yearly history and physical exam that includes oral cavity, thyroid, genitals, breast exam for females, and a complete skin exam. - All patients should visit their dentist for oral/dental examination and cleaning; at least yearly for most patients and every 6 months for those with oral chronic GVHD. - Screening for breast (in women who have not received TBI), cervical, colorectal and prostate cancer should follow established Albertan/Canadian guidelines (www.screeningforlife.ca & for prostate cancer www.canadiantaskforce.ca). - For women who have received TBI: screening mammography starting at age 25 or 8 years after radiation exposure, whichever occurs later but no later than age 40.
- HCT recipients who have received radiation within a particular field, for example chest and those with familial cancer syndromes will require an individualized plan for malignancy screening. - There are no proven screening measures for t-MN after auto-HCT; yearly CBC with early workup of cytopenias for up to 10 years post-transplant may be considered.

# Renal Disease
The definition of chronic kidney disease (CKD) encompasses both decreased kidney function (glomerular filtration rate (GFR) <60 mL/minute) and kidney damage other than decreased GFR (ex. albuminuria) with duration  3 months. 25 Estimates of the cumulative incidence of CKD in the months and years after HCT vary widely at 7 to 48%. 26 In one report, 4% of long-term survivors of allo-HCT (19% of the long-term survivors who had developed CKD) developed end-stage renal disease. 27 In both the general population 28 and the post-HCT population, 29 CKD is independently associated with increased mortality, particularly cardiovascular mortality. Risk factors for CKD after HCT include history of acute kidney injury (AKI), occurrence of acute & chronic GVHD, age 45 at HCT, pre-HCT baseline GFR <90 mL/minute, hypertension and exposure to high dose total body irradiation. 26 While CKD may arise from a number of clinicopathologic entities after HCT; the best described being thrombotic microangiopathy, viral nephropathies and nephrotic syndrome; it is most commonly idiopathic or as a result of incomplete recovery from acute kidney injury early post-HCT. 30 These pathologies have been recently reviewed and are summarized from these sources in Table 1. 26,30,31 Table 1. Etiologies of chronic kidney disease after hematopoietic cell transplant Proteinuria, even microalbuminuria, particularly after allo-HCT, is increasingly recognized as a prognostic marker. Specifically: 1) those with albuminuria at day 100 post-HCT have a significantly higher risk of non-relapse mortality by one year post-HCT (predominantly due to GVHD and infection), and 2) those with albuminuria at any point between day 100 and one year post-HCT have an increased risk of developing CKD. 24,30 Recommendations:
- All HCT recipients should have at least yearly monitoring of creatinine.
- Allo-HCT recipients should a spot urine albumin/creatinine ratio yearly.
- All patients should have at least yearly blood pressure evaluation and treatment per Canadian (CHEP) guidelines (essentially target BP <140/90 for most patients). - Basic medical management of CKD includes initiation of an ACE inhibitor or ARB for proteinuria, tight glycemic control for diabetics, aggressive management of cardiovascular risk factors and avoidance of nephrotoxins.  Because the onset of LONIPCs is often insidious, particularly for BOS, with the potential for significant loss of lung function before symptoms develop, post-HCT screening pulmonary function tests (PFTs) are essential. The approach to abnormal PFTs begins with history and physical exam to elucidate recent or current infections. The investigation is guided by history, physical exam, and pattern of abnormal PFT, but generally begins with chest x-ray (CXR) and non-invasive infectious workup such as nasopharyngeal (NP) swab for respiratory viruses and sputum culture. If no clear etiology is found or empiric therapy fails, the next steps are guided by acuity of the presentation but generally include obtaining a CT chest and referral to the BMT pulmonary clinic with consideration of bronchoscopy with bronchoalveolar lavage +/-lung biopsy.

# Recommendations:
- The approach to prevention of late pulmonary infections are outlined in the bacterial/pneumocystis prophylaxis, fungal prophylaxis and vaccination chapters of these guidelines. - For autologous-HCT recipients: PFT at 6 weeks post-HCT for those who received potentially pulmonary toxic conditioning. For all, at least yearly history and physical exam for signs and symptoms of pulmonary disease is recommended. - For allogeneic-HCT recipients: routine PFTs for all patients every 3 months for the first year post-HCT followed by yearly PFTs until 5 years post-HCT. For those with active cGVHD beyond 1 year post-HCT, continued every 3 month PFTs should be strongly considered. History and physical exam should accompany PFTs. - Abnormal PFTs or new respiratory symptoms should be worked up promptly with CXR +/-NP swab and sputum culture. For clinical presentations that are not consistent with upper respiratory tract infection or community-acquired pneumonia, CT chest and referral to the BMT pulmonary clinic are suggested. 

# Endocrine Disease
Thyroid Function: Hypothyroidism is relatively common after HCT, occurring in up to 30% of long-term survivors. 40 Risk factors include younger age at HCT, radiation (neck, mediastinal or total body) and exposure to busulfan and cyclophosphamide. 20,40 Symptoms of hypothyroidism are non-specific and include fatigue, cold intolerance, weight gain, constipation and dry skin. Hypothyroidism is also a secondary cause/contributor to hyperlipidemia.

# Hyperlipidemia and Diabetes:
As discussed in the cardiovascular disease section above, both autologous and allogeneic HCT recipients acquire cardiovascular risk factors such as hyperlipidemia and diabetes faster and more frequently than the general population. While GVHD & immunosuppressive therapy are well known risk factors for hyperglycemia and hyperlipidemia, 41 it should be noted that HCT survivors at least five years post-transplant without active GVHD and not on immunosuppressive therapy had double the risk of developing metabolic syndrome versus the age-matched population and this risk was independent of allo-versus auto-HCT. 10 As discussed in the cardiovascular disease section above, management of diabetes should follow standard practice for that of the general population and management of hyperlipidemia should be guided by global cardiovascular risk.

# Adrenal Insufficiency:
A single centre study found that the cumulative incidence of adrenal insufficiency after allo-HCT was 13%, while it was 1% after auto-HCT. 42 Those who are treated with long courses of corticosteroids for GVHD are particularly at risk. An ACTH stimulation test may be used to confirm the diagnosis of adrenal insufficiency. Management of adrenal insufficiency includes initiation of physiologic corticosteroid dosing followed by a very slow taper. Weak data and expert opinion suggest that an alternate day tapering regimen may reduce the risk of adrenal insufficiency. 40 Additionally, a medical alert bracelet or information card should be worn or carried and patients should be alerted to seek immediate medical attention if they develop signs or symptoms of adrenal insufficiency (ex. nausea/vomiting/abdominal pain/postural hypotension).

# Gonadal Dysfunction and Fertility:
Gonadal dysfunction and infertility are reviewed elsewhere 1,2 .

# Recommendations:
- Yearly thyroid examination and TSH measurement for all HCT recipients. - A slow terminal taper of corticosteroids is required for those receiving prolonged courses (>3 weeks) for treatment of GVHD. - A high index of clinical suspicion for adrenal insufficiency should be maintained when tapering patients from prolonged courses of corticosteroids. - Management of diabetes and hyperlipidemia within the context of global cardiovascular risk as outlined in the "Cardiovascular disease" section. - Workup and management of gonadal dysfunction and infertility as published 1,2 .

# Management of Chronic Pain
Survivors of HCT may experience chronic pain related to a number of treatment-related complications such as GVHD, peripheral neuropathy and non-specific cramping/muscle spasm among others. Management of chronic pain requires a multi-disciplinary approach that includes HCT providers, palliative care providers, pharmacists, and psychosocial providers.

# Recommendations:
- HCT recipients with chronic pain should be managed within a multi-disciplinary team that includes HCT providers, pharmacists and the psychosocial team within the Alberta Blood and Marrow Transplant Program with low threshold for referral to the palliative care team at the Tom Baker Cancer Centre.

# Transfusion
In general, most HCT recipients do not require transfusion in the post-engraftment period. However, if transfusion is required, thresholds for transfusion of red cells and platelets should be individualized based on the specific clinical circumstances (ex. symptoms, co-morbidities, underlying disease etc.). Product attributes for transfusion as recommended below (i.e. irradiation and CMV status) are in agreement with established Canadian guidelines. 43,44 Appropriate blood-group products for ABOincompatible allo-HCT are reviewed in the "ABO Incompatibility" chapter of these guidelines.

# Recommendations:
- Red cell and platelet transfusion thresholds should be individualized based on clinical circumstances. - The appropriate blood-group products for transfusion after ABO-incompatible allo-HCT per the "ABO incompatibility" chapter. - For allo-HCT recipients: irradiated blood products should be used from start of conditioning until the later of: 1 year post-HCT, end/"burn out" of chronic GVHD or discontinuation of immunosuppression. - For auto-HCT recipients: irradiated blood products for 7 days prior to stem cell collection and from start of conditioning until 3 months post-HCT, or 6 months post-HCT if TBI was part of conditioning. - All auto-and allo-HCT recipients should receive standard leukoreduced ("CMV safe") blood products. Mental Health A significant minority of HCT survivors will experience persistent anxiety, depression and/or posttraumatic stress disorder in the years after transplant. 45 

# Recommendations:
- Long-term follow up visits should include screening for mental health concerns. If concerns are identified, patients should be referred to mental health providers and/or community resources as appropriate. 

# Summary
Upon notification of a potentially or confirmed microbially-contaminated or otherwise nonconforming cellular therapy product the recipient's transplant physician will:
- Notify the recipient of the non-conformance and ensure the recipient receives follow up care/treatment to reduce risks associated with the non-conforming product. This will be documented in the recipient's medical record. - Notify the donor transplant physician.
- Notify the Program Quality Manager.
- Notify Cellular Therapy Lab (if not yet notified). CTL will initiate non-conforming product investigation according to applicable SOP's. - In the case that the donor is an unrelated donor the physician will contact the Canadian Blood Services Stem Cell Registry Case Manager on call at 613-296-6147. Registry personnel must notify the transplant centre of the non-conformance.
Upon notification of a potentially or confirmed microbially-contaminated or otherwise nonconforming cellular therapy product the donor's transplant physician will:
- Notify the donor of the positive microbial result. Ensure the donor receives follow up care if applicable. This discussion shall be documented in the donor's medical record and the donor's regular physician should be advised.

# Background
Despite rigorous quality control and adherence to good manufacturing practices, cellular therapy products (CTPs) may occasionally fail to meet the high standards set for cellular therapy. These products may still be suitable for use, and in most cases are the most appropriate products for the patient. The purpose of these guidelines is to ensure notification and appropriate follow-up of the donor and recipient of these products, notification of the donor and recipient physicians and to ensure notification of regulatory agencies. These guidelines are also intended to standardize the management of patients receiving non-conforming products, in accordance with the foundation for accreditation of cellular therapy (FACT) standards. The identification of any of the above situations will require the following protocol(s) to be followed:
- For cellular therapy products with potential or proven microbial contamination: a. A non-conforming product investigation will be initiated by the Cellular Therapy Laboratory. b. The recipient and donor transplant physicians shall be informed of the positive culture result or a potentially contaminated product, and this discussion shall be documented in the medical record. c. In the case of allogeneic cellular therapy products with positive microbial cultures, the donor physician shall be advised of the positive result in order that he or she can arrange appropriate follow-up of the donor. d. All products will have aerobic, anaerobic and fungal cultures drawn and kept in culture for 5-14 days to allow isolation of fastidious organisms. This should be indicated on the requisition. e. Patients should receive a dose of Vancomycin before infusion of the product, with further doses based upon results of repeat cultures, likelihood of falsely positive cultures and the patient's clinical status. f. Daily blood cultures will be drawn from the patient for a minimum of 3 days after infusion of the cellular therapy product. g. Fevers should be managed according to appropriate guidelines, with repeat blood cultures drawn according to guidelines for management of febrile neutropenia or based on advice of the infectious disease consultant. h. The potential for infusion of a microbially-or endotoxin-contaminated cellular therapy product should be considered in patients with flushing, high fever (> 2 degree C rise from baseline), rigors, confusion or circulatory collapse shortly after infusion and appropriate management instituted. Appropriate antibiotic treatment should be initiated and an infectious disease consult called as needed. i. Canadian Blood Services Stem Cell Registry must be informed immediately of positive microbial test results on products collected for distribution outside the ABMTP. They can be reached by calling the Registry On Call Case Manager at 613-296-6147.

# For cellular therapy products with increased potential for infusion-related adverse events:
a. A non-conforming product investigation should be initiated by CTL for products that fail to meet release criteria or when a deficiency or error occurs during processing. b. The patient should be advised of the product variance and of any action to mitigate risk (such as increased premedication or monitoring post-infusion). This should be documented in the patient's medical record. - Malnutrition risk may be mitigated through initiation of nutrition support, preferably through the use of enteral nutrition (tube feeding).
- Nutrition support should be initiated for hematopoietic cell transplant patients if: inadequate intake (less than 60% of requirements) for 5 days or likely to remain inadequate for >5 days, or weight loss in a euvolemic patient of >5% in one month or >2% in one month if BMI <20kg/m 2 , except for those patients meeting these criteria during the expected period of stomatitis and for 7-10 days after resolution of stomatitis.
Background/Rationale (for doing things the way you propose)
Patients undergoing hematopoietic cell transplant (HCT) are at risk of malnutrition due to the gastrointestinal (GI) side effects of the treatment, which impede oral intake, including but not limited to: mucositis, anorexia, dysguesia, nausea, vomiting, and diarrhea 1,2 . As a result, patients often are unable to consume enough food to adequately meet their nutritional needs during transplant, with some consuming less than 60% of their estimated requirements for one to two weeks  which, is the defined criteria in the literature for inadequate oral intake among cancer patients. Decreased oral intake can lead to subsequent weight loss, which is associated with non-relapse mortality among HCT patients 6 . Body mass index (less than 18.5kg/m 2 , underweight 7 ) and weight loss were historically used to identify malnutrition, but are no longer considered effective markers on their own 5 . Assessment and diagnosis of malnutrition is not always straightforward and requires dietitian involvement early in the transplant process. Malnutrition can be divided into categories of mild, moderate and severe. Individuals who have more than two of the following are considered severely malnourished: obvious muscle wasting, loss of subcutaneous fat, decreased functional status, weight loss of > 2% in 1 week, 5% in 1 month, or 7.5% in 3 months 8 or consume less than 60% of recommended nutritional intake for 2 weeks or more  . Muscle loss comprises a large proportion of short-term weight loss, wherein immobile or bedridden hospitalized patients can lose up to 0.5% of total body muscle mass per day 9 , with considerable muscle loss occurring during a prolonged hospital stay 10 . Malnutrition is associated with lower health-related quality of life 11,12 , impaired functional ability 12,13 , higher rates of infection 14 , impaired wound healing 15 , longer hospital length of stay 16,17 , increased health care costs 16 , and higher mortality 18,19 .
Both enteral and parenteral nutrition can be utilized to provide nutrition support to HCT patients who are at risk of malnutrition and whose oral intake is impeded by the gastrointestinal side effects of treatment. Parenteral nutrition may be indicated when a patient has a non-functional gastrointestinal tract (i.e. bowel obstruction or paralytic ileus) or in the presence of high gastrointestinal losses (diarrhea, vomiting, short bowel syndrome) 20 . Total parenteral nutrition (TPN) requires central venous access such as a percutaneous non-tunneled central catheter, a tunneled cuffed catheter, a peripherally inserted central catheter (PICC) or an implanted port prior to initiation 21 . Complications of parenteral nutrition may include refeeding syndrome, infection, thromboembolic events, hyperglycemia, cholestasis, hypertriglyceridemia, metabolic bone disease 21,22 and acalculous cholecystitis 23 .
Enteral nutrition can be delivered via nasogastric or nasoduodenal/nasojejunal tubes (short term, ideally less than 4 weeks) or via endoscopically, surgically or radiologically placed percutaneous gastric/jejunal tubes (long term) 24 . Naso-enteric feeding tubes can contribute to both physical and psychological discomfort for the patient, due to the constant presence of the tube in the nose and throat, potential to cause irritation from friction and possibly more serious complications of nasopharyngeal lesions, sinusitis or reflux esophagitis, tube dislocation and/or movement within the nares and throat, and the tube presence being a reminder of illness 25 . Additionally, clinicians may be concerned about risk of bleeding during naso-enteric feeding tube insertion. Prophylactic platelet infusion (i.e. transfuse if platelet count <30x10 9 ) pre-insertion may help to mitigate this risk, with one study demonstrating no association between thrombocytopenia and increased risk of bleeding after feeding tube insertion among critically ill oncology patients 26 .
Nasogastric tubes may be advantageous over nasoduodenal/nasojejunal tubes due to: (1) decreased cost, as they can be inserted at the bedside by a nurse, rather than by a physician in fluoroscopy, (2) ability to infuse either intermittent (bolus) or continuous tube feeds and (3) more physiological for motility and hormones 27 and medication administration 28 . Nasoduodenal/nasojejunal feeds require a pump for continuous infusion and may be preferred over nasogastric tubes in settings of intractable vomiting and to reduce risk of aspiration, although this risk is not entirely eliminated 27 . However, a continuous tube feed may impact patient quality of life as it can limit activity when a patient is connected to the pump all day 28 . Bolus feeding (gastric feeds only) may contribute to increased risk of aspiration and to increased incidence of diarrhea, depending on rate of formula infusion 28 .
Although parenteral nutrition may be delivered more consistently than enteral nutrition due to interruptions related to gastrointestinal intolerance of the enteral formula, enteral nutrition is advantageous for a number of reasons including prevention of bacterial translocation from the GI lumen to the rest of the body 27 , maintenance of gastrointestinal function and mucosal integrity, fewer infections, decreased length of stay and decreased financial cost 29,30 . Nasogastric feeding tubes are associated with a lower risk of infection, but are associated with a higher risk of tube dislodgment and a poorer quality of life than percutaneous feeding tubes 31 . Enteral nutrition may be discontinued for a number of reasons including nausea, vomiting, diarrhea, psychological intolerance, tube blockage or displacement 32  Both the American Society of Parenteral and Enteral Nutrition (A.S.P.E.N.) and the European Society for Clinical Nutrition and Metabolism (E.S.P.E.N.) recommend enteral nutrition over parenteral nutrition for nutrition support among HCT patients 33,34 . A.S.P.E.N. recommends enteral nutrition in HCT patients with a functioning gastrointestinal tract, and nutrition support in malnourished patients anticipated to be unable to ingest and/or absorb adequate nutrients for a prolonged period of time 33 . E.S.P.E.N. recommends initiation of enteral nutrition except in situations of severe mucositis, intractable vomiting, ileus, severe malabsorption, protracted diarrhea or symptomatic gastrointestinal graft versus host disease (GVHD), when parenteral nutrition could be provided instead 34 .
A paucity of recent studies demonstrated benefits of enteral nutrition over parenteral nutrition among allogeneic HCT patients, although the evidence is mostly from lower-quality observational studies. In a larger randomized controlled trial, Andersen et al. 32 compared enteral nutrition to standard of care among patients receiving allogeneic stem cell transplants (~1/3 myeloablative conditioning chemotherapy, ~2/3 reduced intensity conditioning chemotherapy) and found that 43% of patients receiving myeloablative chemotherapy tolerated enteral nutrition for a median of 8 days and received a median of 73% of goal enteral nutrition calories and protein. The authors suggest that because patients tolerate enteral nutrition, it could be used in place of parenteral nutrition more frequently to the benefit of decreased costs and parenteral nutrition-related complications 32 .
A large retrospective cohort study 35 compared enteral nutrition, parenteral nutrition and inadequate nutrition among allogeneic HCT patients and found an that enteral nutrition was associated with reduced non-relapse mortality and lower incidence of acute GVHD GI tract compared to the other two groups. Another retrospective cohort study 36 that compared enteral and parenteral nutrition among allogeneic stem cell transplant patients showed a decreased risk of infection among those receiving enteral nutrition. A separate prospective cohort study 37 compared enteral and parenteral nutrition among allogeneic stem cell transplant patients receiving myeloablative conditioning treatment found an association between enteral nutrition and improved neutrophil and platelet engraftment, protection from grade 3-4 acute graft versus host disease and improved overall survival. In contrast, parenteral nutrition was associated with increased early mortality and delayed platelet engraftment 37 . A systematic review 38 included the two aforementioned cohort studies 36,37 and concluded that enteral nutrition may be superior to parenteral nutrition based on their results. A second systematic review 39 included these same two observational cohort studies 36,37 , as well as a pilot study 40 , and a randomized study that ended prematurely 41 . They also concluded that enteral nutrition, in conjunction with medications to improve tolerance (antiemetics, antidiarrheals, analgesia), may be associated with a decreased risk of infectious complications and prevention of GVHD compared to parenteral nutrition. 

# Details of Standard Practice in Alberta
There are currently no standardized practice guidelines for the use of nutrition support in adult HCT patients in Alberta. In the pediatric population at the Alberta Children's Hospital, approximately 80% of HCT patients receive a nasogastric feeding tube for nutrition support during transplant. Of these, approximately 50% -75% of the high intensity HCTs will also require parenteral nutrition as a supplement and/or as a bridge until the nasogastric tube can be reinserted and/or enteral nutrition reinitiated if the feeding tube remains insitu. Many of the pediatric HCT patients are discharged home on the Home Enteral Nutrition Program and patients unable to tolerate or those who refuse nasogastric feeds have longer hospital admissions.
Additional randomized controlled trials comparing enteral nutrition to oral and/or parenteral nutrition are unlikely to be conducted in this population. Given the possible beneficial effects of enteral nutrition noted in both the literature and practice at the Alberta Children's Hospital, we propose an algorithm to guide the initiation of nutrition support among adult HCT patients in Alberta (Figure 1). We propose a trial of one year. The nutrition support algorithm should be discussed during the pretransplant interview so that patients are aware of possible nutrition support during transplant. After one year of standard practice implementation, we will compare the following to the previous year: