A Phase Ib to Investigate the CD123-targeted DART Flotetuzumab Following Allogeneic Transplant for Patients With CD123+ Acute Myeloid Leukemia
Phase: PHASE1
Conditions: Leukemia, Myeloid, Acute
Sponsor: Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

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Protocol Title:  A Phase Ib to Investigate the CD123-targeted DART Flotetuzumab 
Following Allogeneic Transplant for Patients with CD123+ Acute Myeloid Leukemia 
Sponsor: 
Johns Hopkins Bone Marrow Transplant P01 CA015396 
Principal Investigator: 
Jonathan A Webster, MD 
Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins 
Hospital 
1650 Orleans Street, CRB1 Rm 245 
Baltimore, MD 21287  
410-614-9106 (p)
410-614-7279 (f)
jwebst17@jhmi.edu
Statistician: 
Ravi Varadhan PhD 
Investigational Agent: 
Flotetuzumab, provided by MacroGenics 
IND#:  
146995 
Local Protocol#: 
J21134 (IRB00235421) 
Funding: 
This trial is funded through the Johns Hopkins BMT P01 
CA015396 
Protocol Type / Version # / Version Date: Version 3.0/JMay 15, 2023
NCT05506956
 

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Table of Contents 
1. Objectives ...................................................................................................................... 5 
1.1. Primary Objective................................................................................................................5 
1.2. Secondary Objective(s) ......................................................................................................5 
1.2.1. Response-related Objectives ................................................................................. 5 
1.2.2. Toxicity-related Objectives ..................................................................................... 5 
2. Background .................................................................................................................... 5 
2.1. Introduction .........................................................................................................................5 
2.2. Allogeneic Transplant in AML ...........................................................................................6 
2.3. MRD and Post-transplant Relapse Risk ...........................................................................6 
2.4. Other Risk Factors for Post-Transplant Relapse ............................................................7 
2.5. Peritransplant Maintenance Therapies ............................................................................8 
2.6. Prognosis and Treatment of Post-Transplant Relapse in AML .....................................9 
2.7. Leukemic Stem Cells in AML .............................................................................................9 
2.8. Flotetuzumab Pre-clinical Development ........................................................................ 11 
2.9. CD123-Targeted Therapies in Clinical Trials ................................................................. 12 
2.10. Rationale for the Proposed Study ................................................................................. 13 
3. Patient Selection and Enrollment ............................................................................. 14 
3.1. Inclusion Criteria ............................................................................................................... 14 
3.2. Exclusion Criteria.............................................................................................................. 14 
3.3. Inclusion of Women and Minorities ................................................................................ 15 
3.4. Informed Consent ............................................................................................................. 16 
4. Study Design and Schedule .................................................................................... 16 
4.1. Pre-Treatment Plan ........................................................................................................... 16 
4.2. Treatment Schedule .......................................................................................................... 16 
4.3 Flotetuzumab Dosing ......................................................................................................... 17 
4.4 Timing of Initiation and Criteria for Subsequent Treatment ......................................... 18 
4.5. Premedications and Prophylaxis .................................................................................... 18 
4.6. Study Parameters.............................................................................................................. 21 
4.7. Dosing Delays and Modification for Toxicity ................................................................ 24 
4.7.1. Management of Cytokine Release Syndrome (CRS)/Infusion-related reactions 
(IRR) ..................................................................................................................................24 
4.7.2. Neurotoxicity Monitoring .......................................................................................28 
4.7.3. Tumor Lysis Syndrome .........................................................................................28 
4.7.4. Other Clinically Relevant Adverse Events ............................................................29 
4.7.5. GVHD ......................................................................................................................29 
4.7.6. Immune-related Adverse Experiences ..................................................................29 
4.7.7. Capillary Leak Syndrome ......................................................................................29 
4.7.8. Epstein-Barr Virus Reactivation ............................................................................30 
4.8. Permitted Medications and Supportive Therapies ........................................................ 30 
4.9. Prohibited Therapies ........................................................................................................ 31 
4.10. Concurrent Antineoplastic Therapies .......................................................................... 31 

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4.11. Duration of Therapy ........................................................................................................ 31 
4.12. Duration of Follow-up ..................................................................................................... 32 
5. Disease Evaluations ................................................................................................... 32 
5.1. Disease Status Definitions ............................................................................................... 32 
5.2. Disease Status Monitoring ............................................................................................... 34 
6. Pharmaceutical Information ...................................................................................... 34 
6.1. Flotetuzumab ..................................................................................................................... 34 
6.2 Toxicity ................................................................................................................................ 37 
6.2.1. Definition of Dose-Limiting Toxicity .....................................................................37 
6.2.2. Infusion-related Reaction ......................................................................................38 
6.2.3. Other Toxicities ......................................................................................................39 
7. Correlative Studies ..................................................................................................... 40 
7.1. MRD Monitoring ................................................................................................................ 40 
7.2. Flow Cytometry Studies ................................................................................................... 41 
7.3.  Immune Profiling of the T cell repertoire ....................................................................... 41 
7.4. Cytokine Profiling ............................................................................................................. 42 
7.5. Operating Procedures for Specimen Collection ........................................................... 43 
8. Statistical Methods ..................................................................................................... 44 
8.1. Endpoints ........................................................................................................................... 44 
8.1.1. Primary Endpoints .................................................................................................44 
8.1.2. Secondary Endpoints ............................................................................................44 
8.2. Study Design ..................................................................................................................... 45 
8.3. Analysis of secondary endpoints ................................................................................... 45 
8.3.1. Response ................................................................................................................45 
9. Data Safety and Monitoring Plan .............................................................................. 46 
9.1. Data Reporting .................................................................................................................. 46 
9.2. Management of Safety Data ............................................................................................. 46 
9.3. Adverse Event Definition ................................................................................................. 47 
9.4. Serious Adverse Event (SAE) Definition ........................................................................ 48 
9.4.1. Hospitalization or prolongation of existing hospitalization following the 
completion of flotetuzumab ............................................................................................48 
9.4.2. Life-Threatening Conditions ..................................................................................49 
9.5. Unexpected (unlisted) Adverse Event/Reference Safety Information ........................ 49 
9.6. Adverse Drug Reaction and Toxicity Monitoring .......................................................... 49 
9.7. Toxicity Reporting............................................................................................................. 50 
9.7.1. Special Reporting Situations .................................................................................52 
9.8. Pregnancies ....................................................................................................................... 54 
9.9. Drug Relationship ............................................................................................................. 54 
9.10. Outcome ........................................................................................................................... 55 
9.11. Data Handling and Record Keeping ............................................................................. 55 
9.11.1. Maintenance of Safety Information .....................................................................55 

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9.11.2. Procedures for Reporting Safety Data and Product Quality Complaints (PQCs) 
for Macrogenics Medicinal Products to Macrogenics Scientific Affairs, LLC .............55 
9.11.3. Reporting Procedures for Reporting Safety Data and Product Quality 
Complaints (PQCs) for Non-Macrogenics Medicinal Products .....................................56 
9.11.4. Transmission Methods ........................................................................................56 
10. Ethics .......................................................................................................................... 56 
10.1. Institutional Review Board ............................................................................................. 56 
10.2. Ethical Conduct of the Study......................................................................................... 56 
10.3. Evaluation of Benefits and Risks/Discomforts ........................................................... 57 
10.3.1. Potential Benefits .................................................................................................57 
10.3.2. Measure for Minimizing Risk ...............................................................................57 
10.3.3. Risks/Benefits Analysis .......................................................................................57 
10.3.4. Patient Information and Consent ........................................................................57 
10.4. Financial Disclosure ....................................................................................................... 58 
11. 
References ............................................................................................................. 60 
12. Appendix .................................................................................................................... 66 
12.1. GVHD Staging and Grading ........................................................................................... 66 
12.1.1. Acute GVHD66 .......................................................................................................66 
12.1.2. Chronic GVHD67 ....................................................................................................67 
 

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1. Objectives 
1.1. Primary Objective   
 
Define the maximum tolerated dose (MTD) of flotetuzumab in patients with relapsed/refractory 
AML following alloHSCT. 
 
1.2. Secondary Objective(s) 
 
1.2.1. Response-related Objectives  
1) Assess response (CR, CRi, PR) to flotetuzumab in patients with relapsed AML 
following alloHSCT 
 
1.2.2. Toxicity-related Objectives 
2) Assess acute GVHD incidence  
3) Determine chronic GVHD incidence 
4) Measure non-relapse mortality 
 
2. Background 
2.1. Introduction 
Acute myeloid leukemia (AML) is a heterogeneous disease and treatment outcomes with initial 
intensive induction chemotherapy are dependent on a number of factors including patient age, 
performance status, cytogenetics, molecular markers, and a history of an antecedent 
hematologic disorder or prior chemotherapy.1-4 In younger patients, complete remission (CR) 
rates of 80% can be achieved with intensive chemotherapy, but 5-year overall survival is 
~40%.5 Complete remissions are less frequent with advancing age with <50% of those over age 
70 ever achieving a CR, and a concomitant decrease in 5-year overall survival to ~10% even 
among patients who are healthy enough for intensive chemotherapy.1,2 Thus, most patients with 
a new diagnosis of AML who undergo intensive induction chemotherapy are able to achieve a 
first remission, but long-term survival remains poor due to disease relapse and treatment-
related complications.  This has led to the development of a number of strategies for post-
remission therapy to prevent relapse including consolidation chemotherapy and allogeneic 
hematopoietic stem cell transplant (alloHSCT).5 The majority of new AML patients present with 
disease that is classified as intermediate or poor risk by cytogenetics, and multiple large studies 

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have shown that overall survival in these risk groups is improved by using alloHSCT as post-
remission therapy.1,6,7       
 
2.2. Allogeneic Transplant in AML 
While alloHSCT improves overall survival for the majority of patients with AML, mortality 
remains quite high due to both treatment-related mortality (TRM) and disease relapse.  The 
initial approach to alloHSCT for AML relied on myeloablative conditioning (MAC) and yielded 
relapse rates of 21-24%, but this intensive conditioning regimen was not appropriate for older 
patients and resulted in TRM as high as 43%.8-11 The high rates of TRM with MAC led to the 
development of alternative conditioning regimens that would allow allogeneic stem cell 
engraftment while reducing fatal complications.  The initial reduced-intensity conditioning (RIC) 
regimens led to a significant reduction in non-relapse mortality (NRM) to 6.5-17%, but a 
concomitant increase in relapse incidence ranging from 28.6% to as high as 51% in patients 
with poor risk cytogenetics.12-14 Further reductions in the intensity of conditioning have made 
alloHSCT available to older patients, but this nonmyeloablative (NMA) conditioning approach 
results in relapse rates of 42-54%.15-17 Thus there is a need to develop better strategies to 
identify which patients are at highest risk for post-transplant relapse, develop maintenance 
strategies to augment the graft-versus-leukemia (GVL) effect to reduce disease relapse, and 
develop treatment strategies for patients who relapse post-transplant. 
 
2.3. MRD and Post-transplant Relapse Risk 
The detection of minimal residual disease (MRD) in spite of a morphologic CR is a validated 
prognostic marker for relapse risk in acute lymphoblastic leukemia (ALL), and it has shown 
promise as a marker of relapse risk for AML patients undergoing alloHSCT.  In ALL, the 
detection of MRD prior to transplant is significantly associated with increased relapse risk and 
decreased survival, while the detection of MRD post-transplant has been used to guide pre-
emptive donor lymphocyte infusion (DLI) to stimulate the GVL effect because it is highly 
predictive of relapse.18-27 The ability to reliably detect MRD by both multiparameter flow 
cytometry (MFC) and PCR amplification of the Ig or TCR genes has allowed for extensive study 
of the prognostic significance of MRD in ALL, whereas the latter method is not applicable in 
AML, which has made it necessary to develop alternate markers of MRD.28 In AML, the 
presence of MRD by MFC is highly correlated with the expression of leukemia-specific fusion 
transcripts, and patients with persistent MRD prior to and following transplant have worse 
overall survival.29 For example, Zhou et al. found that patients with persistent MRD by MFC prior 

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to transplant had a three-year relapse-free survival (RFS) of just 17% as opposed to a three-
year RFS of 70% among patients who cleared their MRD prior to a myeloablative transplant, 
and outcomes were even worse for those with MRD post-transplant with a three-year RFS of 
just 13%.30 Subsequent studies have shown that the 3-year cumulative incidence of relapse is 
similar among patients with pre-transplant MRD by MFC who undergo myeloablative (63%) or 
nonmyeloablative conditioning (57%) with nearly all relapses occurring within the first year post-
transplant.31  As an alternative to MFC, the panleukemia marker WT1 is expressed in 90% of 
AML, and WT1 gene expression has been observed to increase prior to cytologic relapse in 
post-transplant patients with higher levels of expression correlating with increased risk of 
relapse.32-34 Goswami et al. analyzed pre-transplant peripheral blood specimens for 74 patients 
who underwent a MAC alloHSCT for AML at the National Institutes of Health, and showed that a 
five-gene RQ-PCR array including WT1 was 89% sensitive and 100% specific in predicting 
post-transplant relapse within one year of transplant.35 This five-gene RQ-PCR array as a 
measure of MRD has been tested exclusively in the setting of MAC alloHSCT where the relapse 
risk is lower than with NMA alloHSCT; thus this technique is likely less sensitive for predicting 
relapse after NMA alloHSCT but should retain its specificity. 
 
2.4. Other Risk Factors for Post-Transplant Relapse 
In addition to the presence of MRD in the peri-transplant period, a number of other factors are 
clearly associated with adverse outcomes following transplant for AML including: complex 
cytogenetics at diagnosis, an initial diagnosis of therapy-related myeloid neoplasm, AML arising 
from an antecedent myeloproliferative neoplasm (MPN) or myelodysplastic syndrome (MDS), 
and AML in 2nd remission or beyond.  A study by the Center for International Blood and Marrow 
Transplant (CIBMTR) of 821 adult patients who underwent alloHSCT demonstrated a 5-year 
overall survival of just 18% among patients with a complex karyotype as compared to 64% for 
those with a favorable karyotype and 50% for all other karyotypes.36 The majority of patients in 
this study underwent MAC alloHSCT, and the relapse-free survival (RFS) at 1-year among the 
patients with complex cytogenetics was <40%.  A study of 545 patients with therapy-related 
AML (t-AML) who underwent alloHSCT demonstrated a 1-year RFS of <50% with a relapse rate 
of <20% for those patients in CR at the time of transplant with more dismal outcomes for 
patients who did not achieve a CR prior to transplant.37 Since the majority of patients in this 
study also underwent a MAC alloHSCT, one might expect a relatively consistent RFS at 1-year 
with decreased TRM and increased relapse in patients who receive less intensive conditioning 
regimens prior to transplant.  Meanwhile, a recent retrospective study of 802 patients who 

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underwent alloHSCT for AML following an antecedent hematologic disorder (MDS or MPN) 
demonstrated a 2-year leukemia-free survival of 45% among patients who received a MAC 
alloHSCT and just 37% following RIC alloHSCT with the vast majority of failures due to relapse 
within the first year.38Thus 1-year RFS appears to be convincingly <50% among patients who 
undergo an alloHSCT for AML with complex cytogenetics, arising after prior chemotherapy, or 
arising from an antecedent MPN/MDS.  The 1-year RFS may be slightly better in patients who 
undergo alloHSCT in CR2 or greater, but the long-term RFS is just 44%.39 
 
2.5. Peritransplant Maintenance Therapies  
Post-transplant maintenance therapies have recently gained traction as a viable strategy for 
relapse prevention across a variety of diseases including AML.  In Ph-positive ALL, the addition 
of a tyrosine kinase inhibitor following transplant has led to improved leukemia-free and overall 
survival.40-42 In FLT3-mutated AML, the multi-kinase inhibitor sorafenib given to all patients after 
alloHSCT has led to a one-year progression-free survival of 95% for patients in CR1/CR2 at the 
time of transplant.43 These examples demonstrate the potential of post-transplant maintenance 
therapy for patients with known mutations, but many patients lack a targetable mutation.  This is 
often the case in non-Hodgkin lymphoma (NHL) where the addition of the CD20 monoclonal 
antibody rituximab in the peri-transplant setting has proven safe and may explain improved 
relapse-free survival in multiple trials.44-46 The introduction of monoclonal antibodies shortly after 
alloHSCT raises concern about how the nascent immune system will respond, but cellular 
immune reconstitution in patients treated with post-transplant cyclophosphamide as part of their 
GVHD prophylaxis is favorable for the early integration of immunological strategies to augment 
anti-tumor immunity.47 For patients with CD19+ ALL and NHL, bispecific antibody therapy with 
blinatumomab has proven to be very well tolerated with 91.7% of patients enrolled in a phase I 
trial completing one cycle of therapy,48 and 27 total patients now having been treated with 
excellent disease-specific outcomes and no non-relapse mortality.  Given limited experience, it 
is unclear if the promising safety and efficacy results with rituximab and blinatumomab will be 
generalizable to other antibodies in the post-transplant setting, but there is great enthusiasm for 
incorporating both monoclonal and bispecific antibodies due to their generally limited side effect 
profile.  Thus, post-transplant maintenance strategies have successfully incorporated 
molecularly targeted therapy and antibodies in a variety of different diseases to reduce relapse 
and prolong survival. 
 

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2.6. Prognosis and Treatment of Post-Transplant Relapse in AML 
When patients do relapse following alloHSCT, the prognosis is quite poor, but the non-tolerized 
allogeneic immune system may enhance the efficacy of treatment.  A study of 263 AML patients 
who relapsed following a RIC alloHSCT demonstrated a subsequent CR rate of just 32% with a 
2-year OS of 14% from the time of relapse.49 Notably, 2-year OS after relapse was particularly 
poor among patients who were treated with chemotherapy alone (4.4-6.8%), whereas a purely 
immunologic strategy using donor lymphocyte infusion (DLI) resulted in an improved CR rate of 
36% with a subsequently better 2-year OS of 25%, although some patients did go on to receive 
a second alloHSCT.  In relapsed FLT3-mutated AML, deeper and more durable responses have 
been achieved with TKIs in the post-transplant setting than in patients who have been treated 
with chemotherapy alone.50 The improved outcomes in post-transplant patients suggest that the 
non-tolerized allogeneic immune system augments the benefits of post-transplant therapies  
 
2.7. Leukemic Stem Cells in AML 
A potential target for post-transplant therapy in AML is the leukemia stem cell (LSC), which can 
be differentiated from normal hematopoietic stem cells (HSCs) by the robust expression of 
CD123.  The identity of LSCs as CD34+CD38- cells was first confirmed by Bonnet et al., who 
determined that human AML cells with this phenotype were capable of differentiation, 
proliferation, and self-renewal when transplanted into non-obese diabetic mice with severe 
combined immunodeficiency disease (NOD/SCID mice).51 However, normal HSCs share this 
CD34+CD38- phenotype as demonstrated by their ability to repopulate NOD/SCID mice.52 Thus 
exclusively targeting CD34+CD38- cells to eradicate AML stem cells is impractical because it 
would also ablate normal hematopoiesis, so the identification of markers that differentiate LSCs 
from HSCs is critical before treatment can be targeted at LSCs.  Recently, Jordan et al. 
determined that the interleukin-3 receptor alpha subunit (CD123) is expressed on >90% of 
CD34+CD38- LSCs in 16/18 AML patient samples, while <1% of CD34+CD38- HSCs express 
CD123 in 5 normal patient samples.  As additional evidence of the importance of this cell 
population, CD34+CD123+ cells from three separate AML specimens were transplanted into 
NOD/SCID mice and engrafted, corroborating that CD123 is expressed on the leukemia stem 
cell.53 The differential expression of CD123 on leukemia stem cells and normal bone marrow 
stem cells suggests that CD123 would be an appealing target for leukemia-directed therapy.  
 
Beyond their potential as therapeutic targets, LSCs also serve as robust markers of MRD.  This 
has been demonstrated using aldehyde dehydrogenase (ALDH) activity instead of CD123 to 

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define subpopulations of CD34+CD38- cells that can be isolated from the bone marrow of most 
AML patients.  In a study at Johns Hopkins, Gerber et al. demonstrated that cells with high 
ALDH activity (CD34+CD38-ALDHhigh) lacked leukemia-specific cytogenetic abnormalities, cells 
with low ALDH (CD34+CD38-ALDHlow) activity were unable to engraft NOD/SCID mice, and 
those with intermediate ALDH (CD34+CD38-ALDHint) activity were the only subpopulation 
capable of producing leukemic engraftment of NOD/SCID mice.54 Thus CD34+CD38-ALDHint 
cells represent LSCs.  Importantly, this CD34+CD38-ALDHint cell population is not present in 
normal bone marrow.  Analysis of serial bone marrow samples from 16 AML patients following 
induction or consolidation chemotherapy demonstrated detectable levels of CD34+CD38-ALDHint 
cells by MFC in 7 patients of whom 6 suffered a subsequent morphologic relapse, while the 
remaining 9 patients without detectable CD34+CD38-ALDHint cells remain in complete 
remission.54 These findings suggest that MFC to detect the presence of CD34+CD38-ALDHint 
cells identifies AML patients with persistent MRD who are at the highest risk of relapse.    
 
More recently, the Jones Laboratory at Johns 
Hopkins has found that LSCs are phenotypically 
heterogeneous, but the heterogeneity was 
consistent and correlated with risk groups and 
outcomes.55 About 40% exhibited an ALDHhigh 
phenotype indistinguishable from normal HSCs, 
and most (85%) harbored poor-risk cytogenetics or 
FLT3/ITD mutations.  No CD34+ AML cells could 
be detected in a quarter of patients, including 
14/21 patients with NPM1-mutations and 6/7 acute 
promyelocytic leukemia (APL) patients. The patients with 
CD34+CD38-ALDHhigh leukemia cells manifested a 
significantly lower CR rate, as well as poorer EFS and OS.  
Patients with no detectable CD34+ AML cells had the best 
EFS, and those with CD34+CD34-ALDHint AML cells an 
intermediate prognosis.  The strong clinical associations with the LSC phenotype validated the 
use of this definition for the clinical study of LSCs.  The heterogeneous LSC phenotypes 
appeared to be a function of where in hematopoietic differentiation the AML arose: unfavorable 
risk AMLs appear to arise from primitive LSCs with the same phenotype as HSCs (CD34+CD34-
ALDHhigh), intermediate risk from less mature LSCs (CD34+CD34-ALDHint), and favorable-risk 
Figure 1.  Expression of CD123 by primary HSCs 
and LSCs. Expression in 3-5 CD34+CD38-ALDHhigh 
HSCs from normals (1st column) and CBF AMLs 
(2nd column), CBF AML LSCs (CD34+CD38-
ALDHint, 3rd), NPM1 mutated LSCs (CD34-, 4th), and 
complex cytogenetic LSCs CD34+CD38-ALDHhigh, 
5th column). Line represents Ab control. * represent 
p values < 0.05 compared to HSCs from normal. 

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from LSCs with mature hematopoietic phenotypes (CD34+CD38- or CD34-). However, despite 
the heterogeneity in phenotype, our group found that all the LSCs expressed CD123 regardless 
of their phenotype, while HSCs from normals and AML patients did not (Figure 1).  
 
2.8. Flotetuzumab Pre-clinical Development 
The identification of CD123 as a marker of LSCs has led to the development of a number of 
therapies targeting CD123 including both monoclonal antibodies and a dual-affinity retargeting 
molecule (DART), flotetuzumab, generated from antibodies to CD3 and CD123, designed to 
redirect T cells against acute myeloid leukemia blasts.  Flotetuzumab has been shown to 
increase the association between CD3-expressing Jurkat cells and CD123-expressing 
malignancies by at least 17-fold compared to control DARTs or non-CD123-expressing 
malignancies.56  Furthermore, flotetuzumab leads to T cell activation with a dramatic increase in 
CD25 expression on CD4+ and CD8+ T cells in vitro upon incubation with CD123-expressing 
malignancies, and a marked T cell proliferation when CD4+ and CD8+ T cells are incubated with 
CD123-expressing malignancies.  The activation and proliferation of T cells by flotetuzumab in 
turn led to CD123-specific cytotoxicity in vitro that was dependent on both the dose of 
flotetuzumab and the effector T cell:target cell ratio.  These findings of DART-mediated T cell 
activation and cytotoxicity were subsequently replicated using primary AML blasts in vitro, and 
the activity of flotetuzumab was also demonstrated when such samples were cultured in the 
presence of stroma.56 Notably, these experiments also demonstrated an increase in TCR 
diversity when next generation sequencing was applied to T cells following exposure to 
flotetuzumab and primary AML blasts.  Ultimately, in vivo experiments using sublethally 
irradiated NSG mice bearing CD123-expressing tumor cells demonstrated that flotetuzumab 
reduced leukemic cell burden by 1415-fold compared to untreated mice.56 
 
To ascertain the safety and potential efficacy of flotetuzumab in primates, toxicology and 
pharmacodynamic studies were performed using cynomolgus macaques.  In this study, 
flotetuzumab was administered using step-wise intra-patient dose escalation to mitigate the 
anticipated cytokine release syndrome (CRS).  This dose escalation strategy proved effective 
with a minimal, transient, first dose effect that correlated with increased IL-6 levels.57  
Importantly, white blood cell count; neutrophils; and platelets remained within the normal range 
during treatment with flotetuzumab, except for one treatment group that had a transient decline 
in platelets just below the reference range.  There was a dose-dependent decrease in red cell 
mass, but this was reversible upon cessation of the drug.57 These findings demonstrate the 

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limited hematologic toxicity of flotetuzumab in primates, which might be expected from the 
differential expression of CD123 on leukemic stem cells and normal hematopoietic progenitors.  
In addition to the safety of flotetuzumab in an in vivo model, the macaque studies also 
demonstrated the extensive depletion of plasmacytoid dendritic cells, which are defined by their 
expression of CD123, by flotetuzumab with subsequent recovery when flotetuzumab was 
discontinued.57 Thus the enumeration of plasmacytoid dendritic cells can serve as an important 
pharmacodynamic marker to verify the on-target effects of flotetuzumab.     
    
2.9. CD123-Targeted Therapies in Clinical Trials 
The in vitro efficacy of CD123-targeted therapies led to multiple trials of these therapies in 
patients with relapsed, refractory, and high-risk AML that demonstrated the feasibility of this 
approach.  In a phase I trial of the monoclonal antibody CSL360, 40 patients with advanced 
AML received the study drug at five different dose levels weekly for twelve weeks without 
reaching a maximal tolerated dose.  Complete, sustained saturation of CD123 by CSL360 was 
seen at the two highest dose levels, but only 2/27 patients (7.4%) in these cohorts achieved a 
complete remission.58 This suggested that monoclonal antibodies directed against CD123 may 
be inadequate to overcome the significant disease burden in the study population.  However, it 
was notable that both patients who achieved a CR had undergone a prior alloHSCT, while only 
5 patients with a history of alloHSCT were treated in these cohorts.58 Thus there was a 40% 
response rate for patients with prior alloHSCT who were treated at an adequate dose level, 
which raises the possibility that the allogeneic immune system is critical for the efficacy of this 
treatment.  Overall, seven patients who had relapsed after alloHSCT were treated with CSL360 
without any evidence that CD123-targeted therapy exacerbates transplant-related toxicities.  
The drug-antibody conjugate tagraxofusp has also been studied in patients with blastic 
plasmacytoid dendritic cell neoplasm (BPDCN) with relapse following alloHSCT, and there has 
not been any evidence that treatment with this CD123-targeted therapy exacerbates transplant-
related toxicities. 59  A subsequent phase I/II study of the flotetuzumab in patients with 
relapsed/refractory AML or intermediate/high-risk MDS demonstrated manageable toxicities of 
this drug at a maximum tolerated dose schedule of 500 ng/kg/day.  In this study, 30% of 
patients treated at the recommended phase II dose (RP2D) achieved a morphologic response, 
and correlative studies demonstrated evidence of T cell activation.60,61 The most significant 
toxicity of flotetuzumab at the RP2D was cytokine release syndrome (CRS) with 81% of patients 
enrolled in the Phase I/II developing CRS or an infusion-related reaction (IRR), although only 
8% of patients treated at RP2D experienced grade 3 events without any grade 4/5 events.61 

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Notably, the severity of CRS with flotetuzumab correlates with the frequency of circulating CD4+ 
T cells,61 which are significantly reduced for at least a year post-transplant compared to patient’s 
pre-alloHSCT baseline and healthy controls.62 Given the demonstrated efficacy and limited 
toxicity of CD123-targeted therapies in relapsed and post-transplant AML patients, it seems 
logical to test CD123-directed therapies in post-transplant patients as a form of post-transplant 
maintenance and for the treatment of post-transplant relapse. 
 
2.10. Rationale for the Proposed Study 
Despite significant advances, the prognosis for patients with AML remains poor with 5-year 
overall survival of just ~40% in younger patients and much poorer long-term survival in older 
patients.1,2,5 AlloHSCT as post-remission therapy has led to improved overall survival when 
compared to consolidation chemotherapy for the vast majority of AML patients who have 
intermediate or poor risk cytogenetics.1,6,7 Due to significant TRM and poor outcomes in older 
patients with MAC transplantation, there have been many studies investigating the feasibility of 
less intensive conditioning regimens such as RIC and NMA, which have shown comparable 
overall survival with decreased TRM but an increased risk of relapse.12-17 As these less 
intensive conditioning strategies become more widely adopted, the need to focus on the 
identification and treatment of AML patients at risk for post-transplant relapse increases.  
Maintenance therapy with tyrosine kinase inhibitors and monoclonal antibodies have proven 
safe and effective across a range of diseases including AML, ALL, and NHL.40-46 LSCs are 
another potential target for post-transplant therapy, and the expression of CD123 readily 
discriminates AML LSCs from HSCs.53 The anti-CD123 monoclonal antibody CSL360 has 
previously demonstrated efficacy in post-transplant patients with relapsed disease, while 
flotetuzumab has demonstrated efficacy in relapsed and refractory patients.58,60 Given this 
preliminary data, we propose a trial of flotetuzumab as post-alloHSCT therapy for AML in 
patients with evidence of disease post-transplant including frank relapse.  We believe that 
treatment with flotetuzumab in this setting will be well tolerated and effective.  Flotetuzumab is 
not approved for use in people with AML.  Its use has not been specifically studied in patients 
with AML following a bone marrow transplant and therefore its use in this study is 
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3. Patient Selection and Enrollment 
3.1. Inclusion Criteria 
1) A confirmed prior diagnosis of AML and underwent an alloHSCT as a form of 
consolidation in a morphologic complete remission 
2) ECOG performance status 0-2 
3) Ability to give informed consent 
4) In agreement to use an effective barrier method of birth control to avoid pregnancy 
during the study and for a minimum of 30 days after study treatment, for all male and 
female patients who are fertile 
5) Age ≥18 years 
6) Prior treatment with a CD123-targeted therapy will be allowed assuming the patient 
did not have a grade 3 or 4 adverse reaction to prior use of this treatment 
7) Normal thyroid function (defined by either a TSH within the reference range, a TSH 
above the reference range with a free T4 within the reference range, or a TSH below the 
reference range with both a free T4 and total T3 within the reference range) or normal 
thyroid tests on supplementation or treatment (defined as a TSH within the reference 
range) 
 
 
8) Patients should be at least 30 days from transplant with morphologic evidence of 
disease progression on bone marrow biopsy 
9) A population of blasts with expression of CD123 is noted. 
10) Peripheral blast count ≤20,000/mm3 at time of initiation on Cycle 1 Day 1 
 
3.2. Exclusion Criteria 
1) No evidence of donor engraftment (100% patient DNA in bone marrow or peripheral 
blood after alloHSCT based on either an unsorted specimen or CD3 sorted). 
 
2) Active AML in CNS or testes 
3) Patients with active, uncontrolled infection.  If an infection is controlled and under 
treatment, then the patient may become eligible. 
4) Patients with active acute or chronic GVHD requiring GVHD therapy (mycophenolate 
mofetil, tacrolimus, sirolimus, or steroids) within 30 days 
5) Patients without active acute or chronic GVHD requiring prophylactic GVHD therapy 
(mycophenolate mofetil, tacrolimus, sirolimus, or steroids) within 30 days  
6) Inadequate end organ function defined as: 

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• 
Hepatic-AST, ALT, and alkaline phosphatase > 3.5X ULN, bilirubin >2.5X 
ULN 
• 
Renal-creatinine clearance <60 mL/min using the modified Cockcroft-Gault 
formula 
• 
Cardiac-Recent myocardial infarction within 6 months, Congestive Heart 
Failure with EF <50%, active pericarditis or myocarditis 
• 
Pulmonary-Need for supplemental oxygen to maintain oxygen saturation 
>92% 
• 
Adrenal-Adrenal insufficiency requiring physiologically-dosed steroids 
7) Women who are pregnant or lactating 
8) Previous or known hypersensitivity to biological agents or constituents of flotetuzumab 
or its source material 
9) Concurrent use of any other investigational drugs 
10) Uncontrolled infection with human immunodeficiency virus (HIV) or chronic infection 
with hepatitis B virus or hepatitis C virus (HCV) 
11)  Any active untreated autoimmune disorders (with the exception of vitiligo, resolved 
childhood atopic dermatitis, prior Grave’s disease now euthyroid clinically with stable 
supplementation) 
12) Previous treatment with radiotherapy or an immunotherapeutic agent in the 14 days 
prior to study drug administration (Cycle 1 Day 1) or 5 half-lifes, whichever is longer 
13) Requirement, at the time of study entry, for concurrent steroids > 10 mg/day of oral 
prednisone or equivalent, except steroid inhaler, nasal spray, or ophthalmic solution 
14) Use of granulocyte colony stimulating or granulocyte-macrophage colony stimulating 
factor in the 2 weeks prior to study drug administration 
15) Prior adverse event with CD123 therapy necessitating therapy discontinuation 
 
3.3. Inclusion of Women and Minorities 
The proposed study is open to both men and women and to all racial/ethnic subgroups.  There 
is no explicit mention of different treatment effects in male and female patients or in different 
racial/ethnic subgroups in the literature.  Therefore, this study will not have separate accrual 
targets for these groups. 
 

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3.4. Informed Consent 
All patients eligible for the study must be evaluated by one of the study investigators.  Informed 
consent must be obtained and the consent form signed.  An eligibility checklist will be completed 
following fulfillment of the on-study requirements for laboratory work and eligibility criteria.  For 
enrollment of non-English-speaking candidates, the policies and procedures mandated by the 
JHM IRB will be followed as listed on the following website:  
https://irb.jhmi.edu/Guidelines/nonenglishconsent.html 
4. Study Design and Schedule 
4.1. Pre-Treatment Plan 
A complete history and physical examination and list of medications will be documented for 
each patient within two weeks of enrollment.  A bone marrow aspirate or biopsy confirming a 
diagnosis of relapsed AML will be documented in the electronic medical record.  A bone marrow 
aspirate/biopsy documenting a CR (<5% blasts) must be performed prior to transplantation.  
Evaluations within 14 days of beginning therapy will include: 
1. A history including a list of active medications and physical exam including body 
height and weight  
2. Hematologic studies:  complete blood count with differential cell counts. 
3. Chemistry panel (including electrolytes, creatinine, uric acid, albumin, total protein, 
calcium and phosphate) 
4. Thyroid Stimulating Hormone 
5. Lactate Dehydrogenase 
6. Hepatic panel:  serum AST, ALT, alkaline phosphatase, total bilirubin, PT/PTT 
7. Urinalysis 
8. An ECG 
9. Pregnancy test (where appropriate) 
10. ECOG performance status 
11. A bone marrow biopsy and/or aspirate including chimerism testing 
 
4.2. Treatment Schedule 
All patients will undergo a bone marrow biopsy prior to enrollment to assess for relapse and 
must have gross morphologic evidence of relapsed leukemia (≥5% blasts) for enrollment in this 
group.  Patients may enroll at any time after day +30 post-transplant.  Patients enrolled on DL1 
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Table 1, and then 500 ng/kg/day on days 7-28.  After one cycle, all patients will undergo a bone 
marrow biopsy to assess response including assessment of MRD.  Patients who fail to achieve 
a CR, CRi, CRh, or MLFS may continue with subsequent induction cycles as a continuous 
infusion up to a total of five cycles.  If there is evidence of response (CR, CRi, CRh, or MLFS) 
and the toxicities of treatment are acceptable, patients will be eligible for two consolidation 
cycles as outlined in Table 1.  Additional bone marrow biopsies for response assessment will be 
performed after the second cycle.  Results will be censored should patients undergo a second 
alloHSCT.  If there is a need to de-escalate dosing based on toxicity, then patients will be 
enrolled on DL-1 using multi-step lead-in dosing as outlined in Table 1, and then 300 ng/kg/day 
on days 5-28 of the first cycle and days 1-28 of subsequent cycles. 
 
Table 1 
Dosing Schedule 
Cycle 
Week 
Days 
ng/kg/day 
Induction: Cycle 1 
 
 
 
DL1 
DL-1 
1 
1 
Day 1 
30 
30 
Day 2 
60 
60 
Day 3 
100 
100 
Day 4 
200 
200 
Day 5 
300 
300 
Day 6 
400 
300 
Day 7 
500 
300 
2 
Days 8-14 
500 
300 
3 
Days 15-21 
500 
300 
4 
Days 22-28 
500 
300 
Consolidation/Reinduction: Cycle 2 and beyond 
2 
1 
Days 1 – 28 
500 
300 
 
4.3 Flotetuzumab Dosing 
Flotetuzumab dosing in this trial will be based on maximum tolerated dose schedule as 
determined in the phase I trial and subsequently modified with multi-step lead-in dosing during 
the first week of treatment.60,61  During week 1 of treatment, patients will receive flotetuzumab 
via continuous infusion using multi-step lead-in dosing as described in table 1.  If they tolerate 
this lead-in dose, then they will be escalated to a dose of 500 ng/kg/day on days 7-28 for DL1 or 

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300 ng/kg/day on days 5-28 for DL-1.  Dosing in subsequent cycles will be as outlined above 
without multi-step lead-in dosing. 
 
4.4 Timing of Initiation and Criteria for Subsequent Treatment 
After HSCT the majority of acute GVHD occurs in the first 60 days.  To ensure patients are 
stable prior to initiating flotetuzumab therapy, the study will start no sooner than day 30 post-
transplant and must be off of immunosuppression for minimum of 30 days prior to initiating 
treatment.  Approximately half of relapses occur within the first year after SCT, with 80% 
occurring within the first two years.63  
 
Patients eligible for subsequent cycles of therapy as consolidation or continued induction, must 
meet the following criteria: 
• 
Peripheral blast count ≤20,000/mm3 
• 
Meeting criteria for end organ function as defined in exclusion criteria #6 
• 
Have had resolution to ≤ Grade 1 of any non-hematologic adverse event deemed to be 
possibly, probably, or definitely related to flotetuzumab 
 
4.5. Premedications and Prophylaxis 
Based on the clinical experience to date; similar findings from other bispecific molecules, such 
as blinatumomab; and reported clinical experience with CAR-T therapies, all patients treated with 
flotetuzumab will receive premedication to prevent or mitigate potential infusion-related reactions. 
Specific pre-treatment regimens are described below.  
Prior to the first dose (Week 1): 
All patients are to be treated as described in table 2. No steroids should be administered for 
infusion-related reaction prophylaxis except as indicated. Patients should receive adequate 
hydration during study therapy, and the addition of IV fluids to maintain intravascular volume 
(e.g., 50-100 mL/hr of normal saline) is recommended for at least 48 hours after the start of 
therapy. 
Prior to Week 2 dosing: 

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The premedication schedule should be followed as described below in table 2. In addition, these 
premedications should be considered in patients if they are resuming flotetuzumab treatment 
after a dose interruption lasting > 1 day in Cycle 1. 
Steroids should not be administered for infusion-related reaction prophylaxis except as indicated 
below, but may be used for the treatment of emerging symptoms as clinically appropriate. 
Patients should receive adequate hydration during study therapy, and the addition of IV fluids to 
maintain intravascular volume (e.g., 50-100 mL/hr of normal saline) is recommended for at least 
48 hours after the start of therapy in Week 2. 
Prior to subsequent doses (after Week 2): 
The premedication schedule should be followed as described below in table 2.  
For infusion-related reactions during the course of treatment, supportive care measures should 
be implemented as outlined in Section 4.7.1. 
IV fluids should be administered for inpatients in all schedules unless contraindicated and 
adequate oral hydration should be emphasized for patients treated as outpatients. 
Table 2 
 
Premedications/Prophylaxis for CRS/IRR 
Medication 
7-day Continuous Infusion Schedule (Induction: Cycle 1* 
Week 1 
Week 2 
Week 3 
Week 4 
Acetaminophen 
(1000 mg PO) 
Or 
Paracetamol 
(1000 mg PO) 
Or 
Ibuprofen 
(400 mg PO) 
Day 1: 30 minutes prior to dosing; 
Then q 8 hrs for 48 hours 
Day 7: 30 minutes prior to syringe 
change; 
Then q 8 hrs for 48 hrs 
None 
None 
None 

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Diphenhydramine 
(25-50 mg IV or 
PO) 
or equivalent 
Day 1:  30 minutes prior to dosing; 
Then q 8 hrs for 48 hrs 
Day 7: 30 minutes prior to syringe 
change; 
Then q 8 hrs for 48 hours 
None 
None 
None 
Famotidine 
(20 mg IV) or 
equivalent 
Day 1:  30 minutes prior to dosing; 
Then q 12 hrs for 48 hrs 
Day 7: 30 minutes prior to syringe 
change; 
Then q 12 hrs for 48 hours 
None 
None 
None 
Dexamethasone 
(or equivalent) 
Day 1:  10-20 mg IV up to 30 
minutes prior to dosing; 
Then 4 mg IV at 12 hours after 
dosing 
Day 7: 10 mg IV up to 30 minutes 
prior to syringe change; 
Then 4 mg 
12 hours later 
None 
None 
None 
7-day Continuous Infusion Schedule (Reinduction/Consolidation: Cycle 2 and Beyond)* 
Acetaminophen 
(1000 mg PO) 
Or 
Paracetamol 
(1000 mg PO) 
Or 
Ibuprofen 
Day 1: 30 minutes prior to dosing; 
Then q 8 hrs for 48 hours 
 
None 
None 
None 

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Diphenhydramine 
(25-50 mg IV or 
PO) 
or equivalent 
Day 1:  30 minutes prior to dosing; 
Then q 8 hrs for 48 hrs 
 
None 
None 
None 
Famotidine 
(20 mg IV) or 
equivalent 
Day 1:  30 minutes prior to dosing; 
Then q 12 hrs for 48 hrs 
 
None 
None 
None 
Dexamethasone (or 
equivalent) 
Day 1:  10-20 mg IV up to 30 
minutes prior to dosing; 
Then 4 mg IV at 12 hours after 
dosing 
 
None 
None 
None 
* If dosing is interrupted for >24 hours during continuous infusion, the premedication schedule for Week 
1 of the Reinduction/Consolidation:  Cycle 2 and Beyond schedule should be followed. 
4.6. Study Parameters 
The studies planned during patient evaluation and therapy are listed in Table 3.  This represents 
the basic follow-up plan and will change based on patient condition.  All attempts will be made 
to collect all correlative studies, however, due to laboratory constraints (weekends, holidays, 
laboratory emergencies or staffing difficulties) and patient constraints (related to intercurrent 
disease, transportation, or inadequate sample), some samples will not be collected or will not be 
suitable for evaluation.  A patient will be considered suitable for evaluation independent of the 
availability of correlative study material.  A variation of +/- 3 days for all study testing and visits 
is permitted. 

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Table 3:  Study Calendar 
Pre-Treatment 
Cycle 1 
Subsequent Cycles 
End of 
Treatment 
Post-
Treatment 
Follow-up 
Parameter 
Pre-
treatment 
Within 14 
days prior 
to Day 1 
Day 1 
 
Day 8, 
Day 15, 
Day 22 
Day 28 
Day 1 
Day 8, 
Day 15, 
Day 22 
Day 28 
 
 
Screening/Administrative 
 
Informed Consent 
X 
 
 
 
 
 
 
 
 
Pre-Treatment 
Cycle 1 
Subsequent Cycles 
End of 
Treatment 
Post-
Treatment 
Follow-up 
Parameter 
Pre-
treatment 
Within 14 
days prior 
to Day 1 
Day 1 
 
Day 8, 
Day 15, 
Day 22 
Day 28 
Day 1 
Day 8, 
Day 15, 
Day 22 
Day 28 
 
 
Demography/Medical 
History 
X 
 
 
 
 
 
 
 
 
Eligibility Criteria 
X 
 
 
 
 
 
 
 
 
Study Drug Administration 
Flotetuzumab 
 
X 
X 
 
X 
X 
 
 
 
Safety Assessments 
Physical 
Examination 
X 
X 
  
 
X 
 
 
X 
 
ECOG Performance 
Status 
X 
X 
 
 
X 
 
 
 
 
Vital Signs 
X 
X 
 
 
X 
 
 
 
 
Weight1 
X 
X 
 
 
X 
 
 
 
 
Height 
X 
 
 
 
 
 
 
 
 
ECG 
X 
 
 
 
 
 
 
 
 
Concomitant 
Medications 
Continuous from the time of signing of ICF until at least 30 days after the last dose of flotetuzumab 
Adverse Events 
Continuous from the time of signing of ICF until at least 30 days after the last dose of flotetuzumab 
Laboratory Assessments 
CBC with Differential 
X 
X 
X 
X 
X 
X 
X 
X 
 
PT, PTT 
X 
X 
 
 
X 
 
 
 
 

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CMP 
X 
X 
X 
X 
X 
X 
X 
X 
 
Magnesium 
X 
X 
 
 
X 
 
 
 
 
Phosphate 
X 
X 
 
 
X 
 
 
 
 
LDH 
X 
 
 
 
 
 
 
 
 
HBV surface antigen 
and hepatitis C 
(antibodies) 
X 
 
 
 
 
 
 
 
 
HIV Antibody 
X 
 
 
 
 
 
 
 
 
Serum HCG or urine 
pregnancy test for 
applicable women 
only 
X 
X 
 
 
X 
 
 
 
 
Pre-Treatment 
Cycle 1 
Subsequent Cycles 
End of 
Treatment 
Post-
Treatment 
Follow-up 
Parameter 
Pre-
treatment 
Within 14 
days prior 
to Day 1 
Day 1 
 
Day 8, 
Day 15, 
Day 22 
Day 28 
Day 1 
Day 8, 
Day 15, 
Day 22 
Day 28 
 
 
Peripheral Blood and 
Bone Marrow studies 
for MRD 
X 
 
 
X 
 
 
X 
 
 
Bone Marrow studies 
for chimerism 
X 
 
 
X 
 
 
X 
 
 
Peripheral Blood and 
Bone Marrow studies 
for immunologic 
correlates 
X 
 
X (Day 
15 
ONLY/P
B 
ONLY) 
X 
 
 
X 
(Cycle 
2 
ONLY) 
 
X (at 6 
and 12 
months 
post-
transplant 
and 
relapse)4 
Peripheral Blood 
serum samples for 
Cytokine 
Measurement  
X5 
X5 
X5 
 
 
 
 
 
 
Disease Evaluations 
Bone Marrow 
aspirate/biopsy 
X 
 
 
X 
 
 
X 
X 
 

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MRD Assessment 
via Peripheral Blood 
and Bone Marrow2  
X 
 
 
X 
 
 
X 
X 
 
Survival, subsequent 
therapy, other 
malignancies3 
 
 
 
 
 
 
 
 
X 
1 Must be assessed prior to dosing on Day 1 of each specified cycle, in case of weight loss of >10% within a cycle, the dose 
of study drug must be recalculated. 
2 See section 5.5.  MRD assessment will be performed on bone marrow using MFC as previously described by Gerber et al., 
where any detectable disease will be considered positive.35,54  Samples will be sent for standard-of-care MFC from the bone 
marrow aspirate, and if a bone marrow aspirate cannot be obtained, tben samples will be sent from the peripheral blood for 
standard-of-care MFC. 
3 This data will be obtained through standard-of-care provider visits that occur following alloHSCT. 
4 The correlative samples will be collected at the time of the patient’s standard of care bone marrow biopsies that are 
performed at 6 and 12 months after transplant.  There is considerable variability in the time at which these are performed. 
5 Samples will be collected pre-dose and once per infusion bag change. 
 
4.7. Dosing Delays and Modification for Toxicity 
4.7.1. Management of Cytokine Release Syndrome (CRS)/Infusion-related reactions (IRR) 
In the first weeks of treatment, patients are at risk for cytokine release syndrome (CRS) and 
infusion-related reactions (IRR). While these reactions occur in the majority of patients treated 
with flotetuzumab (81%), most events are either grade 1 or 2.  The severity of these events 
seems to correlate with the baseline absolute CD3+ T cell count and increasing cytokine levels, 
especially interleukin-6 (IL-6).  The risk of CRS was decreased with two-step lead-in dosing.64  
Due to the relationship between IL-6 levels and the severity of CRS, an early intervention 
strategy with the IL-6 receptor antagonist tocilizumab was used to mitigate toxicity in the phase I 
trial.  CRS/IRR should be graded according to the ASTCT CRS Consensus Grading System65    
 
    Table 4 
 
ASTCT CRS Consensus Grading65 

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    Table 5 
 
 
Definition of High Dose Vasopressor 
Pressor 
High Dose 
(doses less than these would be considered Low Dose) 
Norepinephrine monotherapy 
≥ 20 µg/min 
Dopamine monotherapy 
≥ 10 µg/kg/min 
Phenylephrine monotherapy 
≥ 200 µg/min 
Epinephrine monotherapy 
≥ 10 µg/min 
If on vasopressin 
Vasopressin + norepinephrine 
equivalent of ≥ 10 µg/min* 
If on combination vasopressors 
(not vasopressin) 
Norepinephrine equivalent of 
≥ 20 µg/min* 
 
The above grading scale should be used to grade all infusion reactions in this study, irrespective 
of the underlying mechanism of the reaction. Certain AEs may occur in temporal proximity to 
infusion of study drug and therefore, be considered “infusion-related” while not being considered 
an “infusion reaction;” such events may be graded separately according to CTCAE specific 
criteria version 5. 
 
IRR/CRS should be managed as described below. Every attempt should be made to continue 
the infusion during management of the reaction.  
 
Table 6                                            CRS Severity and Management 
CRS Severity 
Management 

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Non-life-threatening  
• 
Fever 
• 
Tachycardia 
• 
Nausea  
• 
Fatigue  
• 
Headache  
• 
Malaise 
• 
Myalgias 
o Slow the infusion rate by 10-20%. 
o Monitor the patient for worsening of condition. 
o Administer IV fluids, diphenhydramine 
hydrochloride (or institutional equivalent) 50 mg 
IV, acetaminophen 1000 mg PO or ibuprofen 
400 mg PO for fever, and oxygen and 
bronchodilators for mild bronchospasm, as 
appropriate; 
o Administer tocilizumab (4-8 mg/kg IV) if the 
above symptoms do not resolve within 2 hours 
with supportive therapy, or is associated with 
any of the following signs and symptoms: 
▪ 
Temperature > 101.5oF (38.6oC) 
▪ 
Signs of pending respiratory compromise 
as indicated by RR > 20/min  
▪ 
HR > 20 bpm above pre-treatment 
baseline 
▪ 
Note: isolated changes in hemodynamic 
parameters alone that do not require 
intervention without pulmonary 
compromise or fever should not prompt 
immediate use of tocilizumab. 
o Corticosteroids should not be used. 
o Continue infusion at reduced rate and slowly 
increase infusion rate to the original rate in 2 
steps after stabilization or resolution of 
symptoms every 4-6 hours, as tolerated. A more 
gradual increase in the rate of infusion may be 
undertaken after consultation with the Principal 
Investigator. 
 
Requiring mild intervention defined by  
• 
Decreases in BP requiring fluid boluses or 
low-dose vasopressors, requiring 
supplemental oxygen (≤6 L/min by 
supplemental oxygen) to maintain oxygen 
saturation >92%, or  
• 
Grade 2 organ toxicity 
o Slow the infusion rate by 25-50%. 
o Administer IV fluids, diphenhydramine 
hydrochloride 50 mg IV or institutional 
equivalent, acetaminophen 1000 mg PO or 
ibuprofen 400 mg PO for fever, and oxygen and 
bronchodilators for bronchospasm, as 
appropriate and if not administered previously; 
o Administer vasopressors (at doses < 20 ng/min 
of norepinephrine) as needed for circulatory 
support.  
o Tocilizumab (8 mg/kg IV) should be used for the 
above signs if they do not resolve with other 
measures within 2 hours, or that requires the 
use of supplemental oxygen > 4 L by nasal 
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o Corticosteroids may be used for patients that do 
not respond to other measures, including 
tocilizumab. 
o Continue infusion at reduced rate and slowly 
increase infusion rate to the original rate 
gradually by half-rate increments (i.e. if rate is 
reduced from 5 mL/hr to 2.5 mL/hr increase to 
~3.75 mL/hr, then 4.25 mL/hr, then 5 mL/hr) 
after stabilization or resolution of symptoms 
every 4-6 hours, as tolerated. A more gradual 
increase in the rate of infusion may be 
undertaken after consultation with the principal 
investigator. 
o Report the event as a serious adverse event 
(SAE), if appropriate. 
o Monitor for worsening condition; 
 
Life threatening defined by  
• 
Need for high-dose vasopressors, >6 L/min 
of oxygen by nasal cannula to maintain 
oxygen saturations >92%,  
• 
Grade 3 organ toxicity (except 
transaminitis), or  
• 
Grade 4 transaminitis infusion reactions and 
infusion-related events 
o Stop the infusion. 
o TO AVOID EXACERBATION OF INFUSION 
REACTION OR CRS: DO NOT FLUSH THE TUBING 
– ASPIRATE RESIDUAL DRUG FROM THE PORT 
LUMEN. 
o Administer IV fluids, diphenhydramine 
hydrochloride (or institutional equivalent) 50 mg 
IV, acetaminophen 1000 mg PO or ibuprofen 
400 mg PO for fever, and oxygen and 
bronchodilators for mild bronchospasm, as 
appropriate. 
o Provide appropriate circulatory support 
including vasopressors as medically indicated; 
o Administer tocilizumab if not administered 
previously. If administered previously, an 
additional dose may be used for prolonged or 
recurrent episodes. 
o Symptoms that are refractory to tocilizumab 
should be treated with any of the following: 
▪ 
Corticosteroids; doses of 
dexamethasone (or equivalent) of 
greater than 30 mg may be required 
▪ 
Etanercept (or equivalent anti-TNFa) 50 
mg IV, and/or daclizumab (anti-IL2 
receptor) 1 mg/kg IV (where approved); 
o Resume the infusion at previously tolerated 
dose once the infusion reaction has resolved or 
decreased to Grade 1. Increase dose rate to the 
original rate, as prescribed by protocol, e.g., 500 
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increments as tolerated after stabilization or 
resolution of symptoms every 4-6 hours. A more 
gradual increase in the rate of infusion may be 
undertaken after consultation with the Principal 
Investigator. 
o Report the event as a serious adverse event 
(SAE), if appropriate. 
o Discontinue the infusion if not resolved to Grade 
1 within 72 hours. 
Resulting in death 
o Notify the regulatory authorities. 
o Report the event as an SAE. 
 
 
4.7.2. Neurotoxicity Monitoring 
Neurotoxicity, including changes in mental status, has been reported with other T-cell directed 
therapies including chimeric-antigen receptor (CAR)-T cells and CD3xCD19 based bispecific 
antibodies such as blinatumomab and rarely with flotetuzumab. The exact mechanism of the 
toxicity is 
unknown. As a result, additional monitoring of patients receiving flotetuzumab is 
indicated. An alteration in mental status refers to general changes in brain function, such as 
confusion, 
amnesia, loss of alertness, disorientation, defects in judgment or thought, and 
disruption in perception and psychomotor skills. Patients should be monitored for changes in 
mental status or other potential neurotoxic events and should be evaluated for orientation to time, 
place and person at baseline prior to treatment with flotetuzumab and at regular intervals during 
therapy.Any suspected neurotoxic event should prompt full evaluation including imaging studies, 
lumbar puncture and neurological consultation as indicated to rule out other causes. The 
incidence of CNS involvement by AML is low and routine lumbar puncture is not generally 
considered indicated. Patients with known, active CNS leukemia are excluded from the study and 
those with suspected disease must be evaluated by lumbar puncture prior to enrollment. 
Patients need to be counseled during the consent process that they should NOT drive or operate 
heavy machinery while they are receiving flotetuzumab treatment and for 30 days after their last dose 
of flotetuzumab. 
4.7.3. Tumor Lysis Syndrome 
Prophylaxis for TLS should be administered for patients with active AML. Aggressive hydration, 
allopurinol, and oral phosphate binders should be implemented starting preferably 24 hours 
before flotetuzumab administration. Serum chemistries should be closely monitored during 
flotetuzumab administration in accordance with institutional standards for the treatment of acute 
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institutional standards. Patients who develop TLS should be monitored closely for abnormal 
serum chemistries or signs of end organ damage and treated appropriately. 
4.7.4. Other Clinically Relevant Adverse Events 
If a grade 3 non-hematological adverse event occurs that is deemed by the investigator to be 
possibly, probably or definitely related to the study drug, then flotetuzumab will be withheld until 
the toxicity resolves to no more than grade 1 (mild) after which flotetuzumab may be restarted at 
the previously tolerated dose.  If the toxicity persists for more than 14 days, then flotetuzumab will 
be permanently discontinued.  If a grade 4 non-hematological adverse event occurs that is 
deemed by the investigator to be possibly, probably or definitely related to the study drug, then 
flotetuzumab should be permanently discontinued.   
 
4.7.5. GVHD 
If a patient develops definitive evidence of acute GVHD66, flotetuzumab will be permanently 
discontinued.  Study therapy will be permanently discontinued should a patient develop definitive 
evidence of chronic GVHD.67 See appendix for specific GVHD assessment criteria. 
 
4.7.6. Immune-related Adverse Experiences 
Immune checkpoint blockade has been associated with several syndromes associated with the 
breaking of immunological tolerance (19). Although not observed in non-clinical studies to date, 
similar events might occur in patients treated with flotetuzumab. These syndromes include 
pneumonitis, colitis, autoimmune hepatitis, arthritis, glomerulonephritis, myocarditis and 
cardiomyopathy, hypophysitis, thyroiditis, or other autoimmune endocrinopathies. The 
occurrence of any of these syndromes is an AESI. Their occurrence dictates interruption, and 
potentially discontinuation, of study drug administration pending further evaluation. In the event 
of suspected immune-related adverse experiences, the investigator should promptly consult 
with the Sponsor and early consideration should be given to the prompt implementation of 
systemic immune suppression utilizing agents that may include, but are not limited to steroids, 
anti-TNF antibodies, and/or IL-6 receptor inhibitors. 
4.7.7. Capillary Leak Syndrome 
Risk of CLS has been associated with T-cell redirecting therapy, including chimeric antigen 
receptor (CAR)-T cell and CD3-engaging bispecific antibody-based molecules, and reported for 
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with frequency in patients treated with flotetuzumab, a detailed review of recent clinical data 
across all flotetuzumab studies identified 3 patients who received flotetuzumab monotherapy 
that, concomitant with CRS during multi-step lead-in dosing, exhibited rapid weight gain, 
decreased albumin, and systemic edema suggestive of CLS. Please be aware that CLS may or 
may not be associated with hemoconcentration in this patient population.  
Healthcare professionals should monitor for weight gain of greater than 2.0 kg compared to the 
previous day’s weight, fluid status, new onset or worsening edema, and decreased albumin. 
Patient’s fluid status should be managed as clinically indicated with IV fluids and vasopressors if 
hypotensive, and with diuretics if normotensive or hypertensive until the patient’s body weight 
normalizes. Flotetuzumab dose interruption should be considered. Further recommendations 
include administration of 10 mg dexamethasone or equivalent for patients with weight gain of 
greater than 2.0 kg, fluid overload, and edema, non-responsive to diuretics and/or fluid 
management. 
4.7.8. Epstein-Barr Virus Reactivation 
EBV belongs to the herpes virus family. After primary EBV infection, the virus quickly enters the 
latent phase and is characterized by a lifelong presence in B-cells. EBV-reactivation may occur 
in immune-compromised patients, and patients may experience signs or symptoms of 
mononucleosis, such as fatigue, weakness, fever, sore throat, and swollen lymph nodes. In 
immunosuppressed patients, including those who have received flotetuzumab, viral reactivation, 
specifically, EBV reactivation, has been reported. To date, on the CP-MGD006-01 study, four 
patients have experienced EBV reactivation. Reported symptoms included non-CRS related 
fever and fatigue. Rituximab (anti-CD20 antibody) is an effective treatment option in patients 
with EBV-reactivation and should be considered per institutional guidelines. 
   
4.8. Permitted Medications and Supportive Therapies 
 
All concomitant medications for medical conditions other than AML are permitted, as clinically 
indicated.  All supportive therapies, other than anticancer treatment needed for the management 
of subjects enrolled in this study, are permitted including transfusional support as per 
institutional standards. 
The following medications and supportive therapies are examples of supportive therapies that 
may be used during the study: 

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• 
Antibacterial, antifungal, or antiviral agents as prophylaxis and to treat active infections 
•   Antiemetics, antidiarrheals, anticholinergics, antispasmodics, antipyretics, 
antihistamines, analgesics, histamine receptor (H2) antagonists or proton pump 
inhibitors, and other medications intended to treat symptoms or signs of disease. 
•   Transfusions such as red blood cells and platelets are permitted to treat symptoms 
or signs of anemia or thrombocytopenia and should be documented on the 
concomitant medication form. 
 
4.9. Prohibited Therapies 
The following medications are prohibited during this study: 
• 
Concurrent systemic corticosteroids at doses >10 mg of prednisone daily (or equivalent) 
except for mandatory premedication 
• 
Any investigational agent 
• 
Any vaccination except annual inactivated influenza and SARS-CoV-2 vaccination 
4.10. Concurrent Antineoplastic Therapies 
Cytoreduction with hydroxyurea will be allowed for the purposes of achieving an initial peripheral 
blast count ≤20,000/mm3 but must stop at least 24 hours prior to the protocol therapy. However, 
hydroxyurea may be reinstituted at the discretion of the Investigator for the prevention or 
treatment of signs or symptoms of leukostasis during the time of study participation.  The use of 
the following antineoplastic therapies will be specifically disallowed across all groups: 
• 
Other cytotoxic chemotherapy 
• 
Donor Lymphocyte Infusion 
• 
Other monoclonal antibodies, antibody-drug conjugates, or bispecific T cell engager 
antibody constructs 
The institution of any of the above should occur in the context of disease relapse or treatment 
failure leading to the discontinuation of the study treatment. 
4.11. Duration of Therapy 
Treatment is planned for up to five induction cycles and two cycles of consolidation. Treatment 
will continue until one of the following occurs: 
1. Disease relapse after achieving a response 

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2. Serious illness that prevents further administration of treatment (i.e. progressive 
infection not responding to appropriate antibacterial and/or anti-fungal therapies) 
3. Unacceptable adverse event(s) 
4. Elective withdrawal of consent by the patient 
5. Determination by the physician that it is no longer in the patient’s best interest to 
continue the trial 
6. Inability to tolerate the study drug  
7. Initiation of breast feeding by the patient 
8. Patient pregnancy 
9. Delay of the study drug for more than 14 consecutive days due to unresolved 
toxicities 
10. Completion of two consolidation cycles OR five induction cycles 
11. No evidence of anti-leukemic activity (PR or better) after 2 successive cycles 
12. Evidence of progressive disease 
 
4.12. Duration of Follow-up 
Patients will be followed for relapse and death for two years from the first day of the first cycle of 
treatment.  Patients are routinely followed and monitored by JH physicians after alloHSCT or 
chemotherapy, and patients who complete the study and continue to receive their care at JH will 
have survival captured annually. 
5. Disease Evaluations 
5.1. Disease Status Definitions 
Assessment of disease status will be performed based on the following definitions that have 
been modified from Dohner et al:68  
 
Complete Remission (CR)   
1 
Absence of extramedullary disease 
2 
Bone marrow blasts <5% blasts and absence of blasts with Auer Rods 
3 
Absolute neutrophil count (ANC) >1,000/L 
4 
Platelets >100,000/L 
5 
Red cell transfusion independence 
 
CR with incomplete blood count recovery (CRi) 

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• 
Meets all criteria for CR except platelets and/or ANC 
 
CR with partial hematologic recovery (CRh) 
• 
Meets all criteria for CR except platelets (100,000/L BUT >50,000/L) AND/OR 
ANC (1,000/L BUT >500/L) 
 
Partial Remission (PR) 
• 
ANC >1,000/L AND platelets >100,000/L with a decrease of bone marrow 
blasts to 5-25% with at least a 50% reduction in bone marrow blasts from 
pretreatment levels 
 
Morphologic leukemia-free state (MLFS) 
• 
Bone marrow blasts <5%; absence of Auer rods; absence of extramedullary 
disease; no hematologic recovery required 
 
Refractory Disease 
• 
Failure to achieve CR after 1-2 cycles of treatment 
 
Progressive Disease (PD) 
• 
Increase of at least 25% in the absolute number of circulating or bone marrow 
blasts or development of extramedullary disease 
 
Relapsed Disease 
• 
Reappearance of blasts in the blood or bone marrow (≥5%) or in any 
extramedullary site after a CR 
 
Minimal Residual Disease (MRD) 
• 
MRD in AML refers to the presence of leukemic cells below the threshold of 
detection by conventional morphologic methods.  Patients who achieved a CR by 
morphologic assessment alone can potentially harbor a large number of leukemic 
cells in the bone marrow.  This will be assessed using conventional MFC, 
wherein any measurable level of leukemic cells will be considered positive.30 The 
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Onecha et al, and the 5-gene RQ-PCR assay developed by Goswami et al will 
also be used as exploratory correlative studies.54 
 
5.2. Disease Status Monitoring 
Disease status will be confirmed by a bone marrow biopsy within 14 days of study enrollment.  
Additional bone marrow biopsies will be performed at the end of all cycles of treatment, and at 6 
and 12 months post-transplant per the standard-of-care for all patients.  MRD status will be 
assessed concurrently with all bone marrow biopsies via peripheral blood and bone marrow 
samples.  If a bone marrow aspirate cannot be obtained, then MFC should be sent by peripheral 
blood for MRD monitoring. 
6. Pharmaceutical Information 
6.1. Flotetuzumab 
1. Other Names:  MGD006, S80880  
2. Classification:  Dual-affinity Re-targeting (DART) molecule 
3. Mechanism of Action:  The dual-affinity re-targeting (DART) molecule flotetuzumab has 
been shown to increase the interaction between CD123-expressing leukemia cells and T cells 
by 17-fold in vitro.56 This interaction has been shown to selectively promote CD4 and CD8 T-cell 
proliferation in a dose dependent manner, while also activating both CD4 and CD8 T-cells as 
evidenced by increased CD25 expression.  Furthermore, this interaction leads to cellular 
cytotoxicity in primary AML blasts in vitro in the absence and presence of stroma. Subsequently, 
flotetuzumab was shown to be effective in a murine AML model with a 1415-fold increase in 
photon flux from leukemic cells in untreated mice as opposed to those treated with 
flotetuzumab, while a control DART had no effect on tumor growth.56 
 
4. Pharmacokinetics:  The distribution and clearance of flotetuzumab has been investigated 
extensively in cynomolgus macaques.  The cynomolgus macaque is a reasonable model for 
humans, as the tissue distribution of CD3 and CD123 is comparable between the two species.  
The distribution half-life of flotetuzumab is short (~4 minutes) with a volume of distribution of ~1-
2 L/kg), which suggests rapid and extensive binding to target cells in tissues.  Flotetuzumab was 
rapidly cleared at the end of infusion with a mean residence time of 7-9 hours, as expected for a 
molecule of its size (59 kD) that is likely renally cleared.57 
 

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5. Pharmacodynamics:  As CD123 is also highly expressed on plasmacytoid dendritic cells, 
monocytes, and basophils in addition to leukemic stem cells, it is possible to measure levels of 
these cells types as a pharmacodynamics marker.56  In the cynomolgus macaque, a dose of 
100 ng/kg per day led to rapid and extensive depletion of CD123-positive cells with subsequent 
recovery following treatment discontinuation.57 
 
6. Drug Supply:  Flotetuzumab drug product (DP) is provided as a sterile aqueous solution with 
a protein concentration of 0.1 mg/mL in a buffer composed of 10 mM sodium phosphate at pH 
6.0, 150 mM sodium chloride and 0.1 mg/mL polysorbate 80. The concentration and function of 
each component in the DP are summarized below. 
Name of Ingredient 
Concentration 
(mg/mL) 
Nominal Amount 
per Vial (mg) a 
Function 
MGD006 drug substance (DS) 
0.1 
0.5 
Active ingredient 
Sodium phosphate monobasic 
monohydrate 
1.13 
5.65 
Buffer component 
Sodium phosphate dibasic 
0.26 
1.3 
Buffer component 
Sodium Chloride 
8.78 
43.9 
Tonicifier 
Polysorbate 80 
0.1 
0.5 
Surfactant 
 
Drug product is supplied as a sterile aqueous solution packaged in a USP and Ph. Eur. conforming 
Type I borosilicate, 5 cc clear glass vial with a 20 mm  4432/50 gray butyl rubber serum stopper. 
The vial is sealed with a 20 mm TruEdge aluminum closure with a plastic overseal. 
7. MGV002 IV Solution Stabilizer:  When administered by a single ambulatory pump or infusion 
pump configuration, flotetuzumab must be diluted into 0.9% Sodium Chloride Injection, USP (normal 
saline), containing custom MGV002 Flotetuzumab IV Solution Stabilizer. 
The MGV002 Flotetuzumab IV Solution Stabilizer is supplied as a sterile, colorless solution of 
0.9% sodium chloride solution with 0.1 mg/mL polysorbate 80.The MGV002 Flotetuzumab IV 
Solution Stabilizer is packaged in a USP and Ph. Eur. conforming Type I borosilicate, 50 cc clear 
glass vial with a 20 mm 4432/50 gray butyl rubber serum stopper and sealed with a 20 mm 
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8. Drug Dose Solution Preparation and Administration:  Flotetuzumab DP and MGV002 
Flotetuzumab IV Solution Stabilizer will be supplied by MacroGenics for use in this study as 
appropriate to accommodate the method of study drug administration. 
Recommended safety measures for handling and preparation include masks, protective clothing, 
gloves, and vertical laminar airflow safety cabinet. 
Flotetuzumab is administered to patients at exceedingly low doses. 
All doses employed in this study are described in units of 
ng/kg/day. Nanogram measurement is infrequently used in 
clinical practice. 
[A nanogram (ng) is 
1 billionth (1/109) of a gram (g), 
1 millionth (1/106) of a milligram (mg); 
and 1 thousandth (1/103) of a 
microgram (mg)] 
Errors in dilution could result in fatal Cytokine Release Syndrome (CRS). 
Every reasonable precaution should be exercised in the preparation, verification, 
and administration of the Flotetuzumab dose. 
Independent verification of patient weight and of the calculated dose must 
be carried out and documented by a second individual. 
Similarly, the administration pump settings should be independently 
reviewed and documented by a second individual before study drug 
administration commences. 
The method of drug administration is using a single ambulatory pump or infusion pump with 
flotetuzumab dose solution prepared with 0.9% Sodium Chloride Injection, USP (normal saline) and 
MGV002 IV Solution Stabilizer, which allows for intravenous infusion up to 7 days before an 
intravenous bag change is required based on treatment plan.  
9. IV Bag for single ambulatory pump infusion:  The flotetuzumab dose solution is prepared 
for administration using either 150 mL or 250 mL empty intravenous bag composed of either 
polyolefin or PVC.  
The method of drug administration is using a single ambulatory pump or infusion pump with 
flotetuzumab dose solution prepared with MGV002 IV Solution Stabilizer and normal saline 
which allows for intravenous infusion up to 7 days before an intravenous bag change is required 
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Before administration, the parenteral investigational medicinal products should be visually 
inspected. Drug should not be administered if discoloration or foreign particulates are 
observed in the solution. 
Prior to adding 0.9% Sodium Chloride Injection, USP (normal saline), MGV002 IV Solution Stabilizer, 
and flotetuzumab IMP to an empty IV bag as described below for dose preparation, the volume of 
normal saline needs to be calculated based on the predefined total target volume, the specified 
MGV002 IV Solution Stabilizer volume, and the flotetuzumab IMP volume calculated from the Dose 
Calculation Worksheet. 
• 
The dose solution preparation begins with the addition of calculated volume of normal 
saline to an empty IV bag, followed by the addition of a predefined volume of 
MGV002 IV Solution Stabilizer calculated using the Dose Calculation Worksheet. 
Normal Saline and MGV002 IV Solution Stabilizer must be added to the IV bag 
prior to adding flotetuzumab to prevent adsorption of flotetuzumab to the IV 
bag and administration set. 
• 
Add calculated amount of flotetuzumab IMP into the IV bag containing both normal 
saline and MGV002 IV Solution Stabilizer. The amount of flotetuzumab IMP calculated 
for dilution is based upon the patient’s weight and the assigned dosing cohort using 
the Dose Calculation Worksheet and the description in the pharmacy manual. 
• 
When diluted during dose preparation, final flotetuzumab concentrations must be 
within concentration range of 50 ng/mL and 4,167 ng/mL (concentration will vary per 
patient’s weight) to enable 24 hours or up to 168 hours of IV infusion of doses in the 
range of 30 ng/kg/day up to 500 ng/kg/day. 
 
Upon completing the dose preparation steps, gently invert the prepared IV bag to mix the dose 
solution. THE BAG MUST NOT BE SHAKEN. Each intravenous bag contains dose-
formulated flotetuzumab that is intended to be used for no more than 7-days of intravenous 
infusion. Flotetuzumab is stable for 192 hours after dilution in MGV002-stabilized normal 
saline. The dose-formulated flotetuzumab is stable for up to 24 hours of storage after 
preparation prior to 7-days of administration. During the time of the infusion, the infusion bag 
and extension set can be exposed to room temperature. However, if administration does not 
immediately begin, the bag should be stored refrigerated at 2-8ºC (36−46ºF) until 
administration can begin, with the time of administration adjusted to account for the maximum 
of 192 hours of dose-formulated flotetuzumab stability. DO NOT FREEZE the prepared dose 
solution. 
 
6.2 Toxicity 
 
6.2.1. Definition of Dose-Limiting Toxicity 
DLT will be defined employing the National Cancer Institute Common Terminology Criteria 
for Adverse Events, Version 5.0 (CTCAE v5.0), except IRR/CRS which will be defined by 
the modified criteria proposed by ASCT and described in section 4.7.1 and in Table 4. 
DLT is defined as: 

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• 
Grade 4 neutropenia lasting ≥ 42 days from start of cycle in 
absence of evidence of active AML (< 5% blasts). 
• 
The development of acute or chronic graft-versus-host disease during treatment  
• 
Grade 3−5 nonhematologic toxicity that is possibly, probably or definitely related 
to the study drug 
EXCEPT: 
o Grade 3 fatigue, asthenia, fever, anorexia, or constipation 
o Grade 3 nausea, vomiting or diarrhea not requiring tube feeding, total 
parenteral nutrition, or requiring or prolonging hospitalization; 
o Infection, bleeding, or other expected direct complication of cytopenias 
due to active underlying disease; 
o Grade 3 or 4 tumor lysis syndrome (TLS) or disseminated intravascular 
coagulopathy (DIC) if it is successfully managed clinically and resolves 
within 7 days without end-organ damage; 
o Grade 3 or 4 isolated electrolyte abnormalities (i.e., those occurring 
without clinical consequence) that resolve, with or without intervention, to 
Grade 2 levels in < 72 hours will not be considered DLT. 
o Grade 3 CRS/IRR that is successfully managed and resolves within 72 
hours, as this is an expected event that does not require permanent 
treatment discontinuation 
• 
Any non-leukemia-related death occurring within 90 days of treatment initiation 
Treatment discontinuation for adverse events prior to the completion of one cycle will be 
considered a DLT unless the adverse event is disease progression, which necessitates 
alternative therapy, or the adverse event is not possibly, probably, or definitely due to the study 
treatment.  Patients who discontinue treatment prior to the completion of one cycle for 
progressive disease or due to an event that is not possibly, probably, or definitely due to the 
study treatment a will be replaced. 
6.2.2. Infusion-related Reaction 
Infusion-related reaction including cytokine release syndrome (CRS), which may be life-
threatening or fatal, occurred in 81% of patients receiving flotetuzumab. The majority of these 
reactions were mild to moderate in severity, whereas 8% of patients treated at the RP2D 
experienced at least one severe (Grade 3) event. None of these events have been life 
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CRS.  This typically occurs during the initial 48 hours of the first infusion of flotetuzumab. 
Symptoms of infusion-related reactions including CRS may include chills, fever, headache, 
fatigue, flushing, nausea, bronchospasm, and hypotension. Patients should be closely 
monitored for signs or symptoms of these events.  For all patients receiving inpatient 
flotetuzumab infusion, vital signs should be monitored according to the inpatient standard-of-
care.  Management of these events may require either temporary interruption or discontinuation 
of flotetuzumab as described in Section 4.5.1. 
 
6.2.3. Other Toxicities 
In addition to CRS/infusion reactions, a number of adverse events that were felt to have 
possible, probable, or definite relationship to flotetuzumab were observed in ≥10% of patients 
enrolled in the phase I study.  The most common such events included pyrexia in 27.3% of 
patients (Gr ≥3 in 3.5%); nausea in 22.7%; decreased lymphocyte count, decreased platelet 
count, diarrhea, and vomiting in 13.6%; and chills, fatigue, decreased white blood cell count, 
and hypocalcemia in 12.1%; and increased alanine aminotransferase, hypomagnesemia, and 
anemia in 10.6%.  The following grade 3/4/5 treatment-related adverse events have been 
reported:   
• 
Grade 3: infusion-related reaction (12/66, 18.2%); anemia (7/66, 10.6%); febrile 
neutropenia (5/66, 7.6%); and pyrexia, white blood cell count decreased, C-
reactive protein increased, hypocalcemia, hypophosphatemia, pulmonary 
edema, hypotension, hypertension, and delirium (2/66, 3.0% each); and 
lymphocyte count decreased, alanine aminotransferase increased, weight 
increased, urine output decreased, diarrhea, syncope, hypofibrinogenemia, 
thrombocytopenia, arthralgia, musculoskeletal pain, joint range of motion 
decreased, dyspnea, laryngeal inflammation, mental status changes, 
hyperbilirubinemia, and infection (1/66, 1.5% each). 
• 
Grade 4: lymphocyte count decreased and platelet count decreased (8/66, 
12.1% each); white blood cell count decreased (5/66, 7.6%); neutrophil count 
decreased (4/66, 6.1%); and alanine aminotransferase increased, aspartate 
aminotransferase increased, and respiratory failure (1/66, 1.5% each). 
• 
Grade 5: none. 
 

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7. Correlative Studies 
The correlative laboratory studies will be attempted on all patients. However, they are not a 
requirement for participation, and are not formal study endpoints. The overarching goals of the 
correlative studies are to: 
1.  Explore the impact of MRD as measured by conventional multi-color flow 
cytometry (MFC), RNA/DNA-based approaches, and our group’s MFC LSC 
assay54,55, and their impact on RFS in AML patients who receive flotetuzumab 
following transplant. 
2. Characterize the effect of flotetuzumab on allogeneic T-cells, particularly on their 
re-distribution, in vivo expansion, activation, and effector differentiation after 
treatment using MFC. 
3. Characterize the effect of flotetuzumab on T cell receptor diversity. 
4. Characterize the effect of flotetuzumab on T cell gene expression using MFC and 
RNA sequencing. 
5. Characterize gene expression in the tumor microenvironment (TME) using the 
NanoString PanCancer IO360 assay, and assess the impact of TME gene 
expression patterns on response to therapy.69 
6. Characterize T-cell infiltration of the bone marrow using multiplex 
immunohistochemistry (IHC).70 
 
7.1. MRD Monitoring 
The high relapse rate seen in adult AML following alloHSCT indicates the lack of eradication of 
MRD despite morphologic remission.  In AML, the presence of MRD by conventional MFC is 
highly correlated with the expression of leukemia-specific fusion transcripts, and patients with 
persistent MRD prior to and following transplant have worse overall survival.29 Correlative 
specimens will be banked to allow exploration of novel MRD assays in addition to conventional 
MFC.  One such novel assay is a 5-gene RQ-PCR assay developed by Goswami et al. that can 
be run on peripheral blood samples.71 The RQ-PCR assay has previously been used to assess 
MRD in AML patients who underwent a MAC alloHSCT, and demonstrated 89% sensitivity and 
100% specificity in predicting post-transplant relapse within one year of transplant based on the 
presence of MRD pre-transplant.35 The RQ-PCR assay can be performed on peripheral blood 
samples, and it would be more convenient to use in future trials, assuming its performance is 
comparable to a conventional MFC assay for MRD.  An additional advantage of this approach is 
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this patient population.  Another approach will use next generation sequencing (NGS) with a 
panel of 32 genes that are commonly mutated in AML as well as qPCR for NPM1, which cover 
approximately 82% of all AML at a sensitivity of 10-4 for single nucleotide variants and 10-5 for 
insertions/deletions.72 This DNA-based next generation sequencing (NGS) has shown a 71% 
concordance rate with conventional MFC, and pre-transplant MRD by NGS and MFC show a 
similar association with post-transplant relapse and survival.73 Notably, the simultaneous 
presence of MRD by NGS and MFC seems to confer the greatest risk of relapse, so it will be 
particularly helpful to assess both simultaneously.  One limitation of this approach will be the 
need for diagnostic samples, which may be not be available for all enrolled patient.  In addition 
to conventional MFC, we will also use our group’s MFC assay to detect LSCs from bone marrow 
samples.35,54 Our group’s MFC LSC assay has been shown to be more sensitive for MRD than 
conventional MFC assays; this probably results from the fact that LSCs in a large fraction of 
patients do not express the same antigen aberrancy as more differentiated progeny.54,55,74     
 
7.2. Flow Cytometry Studies 
We will perform multi-color flow cytometry on PB and BM specimens before and after 
flotetuzumab using three pre-determined panels of mAbs including but not limited to those 
specific for CD3, CD4, CD8, PD-1, CD45RA, CCR7, CD25, CD27, CD28, CD69, Ki-67, T-bet, 
CD127, FoxP3, HLD-DR, CTLA-4, TNFRII, TIM3, LAG-3, CD160, 2B4, BTLA, KLRG-1, CD16, 
and CD56.  This multi-color approach allows the examination of different CD4+ and CD8+ T cell 
subpopulations (expressing CD45RA, CCR7, CD27, and CD28), phenotypic separation of 
human CD4+FOXP3+ T cells into three distinct subpopulations, and assessment of their 
proliferative status (% Ki-67 cells).75,76  The expression of CD69, HLA-DR and TNFRII will be 
measured to characterize T cell activation status and the expression of co-inhibitory molecules 
(PD-1, TIM3, LAG-3, CD160, 2B4, BTLA, and KLRG-1) will be studied.  Natural killer cells (NK), 
NK-T cells will be enumerated using CD16 and CD56 (NK/NK-T cells). 
 
7.3.  Immune Profiling of the T cell repertoire 
The studies proposed will evaluate the T cell receptor (TCR) diversity in T cells isolated from PB 
and BM from patients before and after treatment with flotetuzumab.  We will determine TCR 
diversity and clonal composition using a molecular and computational approach based on high-
throughput DNA sequencing of rearranged TCR CDR3 regions from T cell genomic DNA.  This 
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arbitrarily complex population of T cells and also permits quantitative description of the clonal 
composition of the population.77  The Luznik laboratory in collaboration with the E. Warren 
laboratory from the Fred Hutchinson Cancer Research Center (FHCRC) has performed 
extensive monitoring and tracking of the TCR repertoires in patients undergoing alloHSCT 
(manuscript in preparation).  We are utilizing an established multiplex PCR strategy to amplify 
the CDR3 region of the TCR, spanning the variable region formed by the junction of the V, D, 
and J segments and their associated non-template insertions followed by Illumina-based 
sequencing methodology, a well-characterized methodology developed by Adaptive Technology 
(http://www.adaptivebiotech.com/technology/).  Sequencing is followed by comprehensive 
bioinformatics analyses focused on determining the diversity of the T cell and B cell repertoires 
as well as the entropy and clonality of each repertoire consistent with previous studies.  Through 
these ongoing studies we have developed substantial experience not only in using and 
analyzing DNA retrieved from unsorted PBMCs but also from sorted T cell subpopulations 
(naïve vs. memory vs. regulatory), paired PB and BM samples as well as DNA retrieved from 
FFPE archived tissues. 
 
We hypothesize that a primary action of flotetuzumab will be to re-direct allogeneic T cells 
toward the CD123+ cells resulting in increased TCR diversity and the emergence of unique 
TCR clonotypes that may be relevant in allogeneic post-transplant anti-tumor immunity.  The 
long-term goal of this correlative work is to uncover biomarkers that predict which patients will 
respond to flotetuzumab.  This correlative work will also provide deeper insight into allogeneic 
anti-tumor immunity, effects of anti-CD123/CD3 mAbs on GVHD, and mechanisms of failure to 
eradicate anti-CD123+ malignancies after flotetuzumab treatment. Exploratory studies to 
characterize T cell transcriptional signature before and after treatment using Human Prime View 
Gene Expression Array (http://www.affymetrix.com) will be also considered to gain further 
insight into T cell function in patients with AML before and after treatment.  While analysis will 
focus on CD8+ T cells, as part of T cell isolation we are routinely sorting CD8+, CD4+, B cells, NK 
cells and tumor cells; these other populations will be stored for future analysis if of interest.  
7.4. Cytokine Profiling 
As a part of PB and BM collection and mononuclear cell isolation we will collect plasma that will 
be used for the measurement of defined cytokines (IL-2, IL-6, IL-10, IFN-γ, TNF-α) to assess 
flotetuzumab and checkpoint inhibitors-induced global T-cell activation.  We will examine the 
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7.5. Operating Procedures for Specimen Collection 
Peripheral blood and bone marrow specimen collection will be performed as delineated in the 
study calendar (Section 4.3) and shown in Figure 2.  Correlative studies will only be collected at 
the times when peripheral blood and bone marrow collections are performed for clinical care.  
All enrolled patients will have bone marrow and peripheral blood samples collected prior to 
treatment with flotetuzumab (day -14-0), following treatment with flotetuzumab (day 28), at days 
180 and 365 post-transplant, and at the time of relapse as illustrated in Figure 2.  An additional 
peripheral blood sample will be collected during the first cycle of treatment with flotetuzumab on 
day 14. 
 
 
Figure 2:  Sample Collection for post-transplant flotetuzumab 
 
Bone marrow: 5 x 8mL will be collected in green top ACD tubes (~40 mL). Re-adjustment of the 
direction of bone marrow aspirate needle should take a place after each 10 cc is collected to 
prevent hemodilution. At the time of collection, green top tubes must be thoroughly mixed to 
prevent clotting. 
Peripheral blood: 5x8mL ACD green top tubes of blood (~40mLs) will be collected at each time 
point. 
Specimens should be labeled with the patient’s study number (given at the time of registration), 
study protocol number, sample collection date and time, and sample source (PB or BM).  Thus, 
the samples will be de-identified, but the principal investigator and relevant study staff will have 
access to the study numbers to allow clinical correlation.  Sample collection date and time, and 
sample source (PB or BM) will be recorded.  All data should be kept in the laboratory log.  At 
each sampling time, BM and PB mononuclear cells (PBMC) will be processed via Ficoll density 
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cryopreserved using a controlled-rate freezer with transfer to the vapor phase of liquid nitrogen 
for long-term storage. 
 
The specimens should be delivered to the Jones Laboratory at the Sidney Kimmel 
Comprehensive Cancer Center immediately after collection.  Members of the Jones Laboratory 
will have access to the de-identified samples for the purposes of the studies outlined herein.    
Analysis of the results including correlation with clinical information will be performed at the 
Sidney Kimmel Comprehensive Cancer Center.  Upon completion of the research protocol (i.e. 
two years from the end of treatment of the final patient), all specimens will be destroyed or 
transferred to the Johns Hopkins Biospecimen and Genomic Data Bank in the Department of 
Pathology based on the patients’ agreement.    
 
8. Statistical Methods 
This is a pilot study of flotetuzumab in patients with AML as post-alloHSCT therapy among 
patients in remission and those with relapsed disease.   
 
 
8.1. Endpoints  
8.1.1. Primary Endpoints 
1. Adverse events and toxicities will be tabulated and reported by type and grade and the 
proportions reported with exact 95% binomial confidence intervals. 
2. The maximum tolerated dose (MTD) of flotetuzumab in patients with relapsed/refractory 
AML following alloHSCT will be determined. 
 
8.1.2. Secondary Endpoints 
 
8.1.2.1. Response-related Endpoints 
1) Report the complete response (CR + CRi) rate in relapsed AML to flotetuzumab 
following alloHSCT. 
 
8.1.2.2. Toxicity-related Endpoints 
2) Report the incidence of acute GVHD  
3) Report the incidence of chronic GVHD 
4) Report cumulative incidence of non-leukemia mortality  
 

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8.2. Study Design 
This study proposal will be a phase 1 trial of flotetuzumab in patients with relapsed/refractory 
AML following alloHSCT.  The first part of the study will be a dose escalation following a 3+3 
design for post-transplant flotetuzumab.  The study will start with the recommended dose of 
flotetuzumab in relapsed/refractory ALL (DL1).  The first three patients will be enrolled and 
monitored for the first cycle of treatment for DLTs through the full DLT period (90 days) before 
enrolling additional patients.  If less than 2 patients experience a DLT, an additional 3 patients 
will be enrolled.  If 0 or 1 out of 6 patients have a DLT, then the dose will be deemed safe and 
considered the MTD of flotetuzumab in the post-transplant setting.  If 2 or more of the first 3 or 6 
patients experience a DLT, then the trial will proceed to enroll patients at DL-1 starting with 3 
patients.  The first three patients on DL-1 will be enrolled and monitored in the first cycle of 
treatment for DLTs through the full DLT period (90 days) before enrolling additional patients.  If 
less than 2 patients experience a DLT at DL-1, an additional 3 patients will be enrolled at DL-1.  
If 0 or 1 out of 6 patients have a DLT at DL-1, then the dose will deemed safe and the MTD.  If 2 
or more of the first 3 or 6 patients experience a DLT, then the trial will be stopped.  An 
expansion cohort of 4 subjects will be also pursued at MTD for flotetuzumab to further 
characterize safety, tolerability and any preliminary signs of biological or clinical activity in this 
cohort.  DLT monitoring will continue in this expansion cohort, and the trial will be stopped if two 
additional subjects experience a DLT.  Any patient who discontinues treatment prior to the 
completion of one cycle of flotetuzumab for disease progression or for an adverse event that is 
not possibly, probably, or definitely due to the study treatment will be replaced. 
 
8.3. Analysis of secondary endpoints 
8.3.1. Response 
Due to practical considerations, our sample size will be limited to a maximum of 16 patients. CR 
rate will be reported as a proportion for the endpoint, along with the exact 90% confidence 
intervals for binomial proportion.  
 
Prior reports indicate that the CR rate in this population of patients is around 30%.49 In Table 7, 
we report the precision and compute the exact 90% confidence intervals for the CR rate 
assuming a range of reasonably anticipated values for the flotetuzumab treatment.   
 
Table 7. CR rates and 90% exact binomial confidence intervals for maximum enrollment at a 
single dose level (N=10) 

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CR rate 
20 
30 
40 
50 
60 
Exact 90% CI 
0-41 
6-54 
15-65 
24-76 
35-85 
 
 
8.3.2. Toxicity-related Endpoints 
The cumulative incidence of acute (grade I-IV, grade III-IV) and chronic GVHD (overall, and by 
extent) will be estimated through competing-risk analysis, wherein death is a competing risk for 
GVHD.   
9. Data Safety and Monitoring Plan 
The study PI will be responsible for the conduction of the study, including the monitoring of the 
study’s safety and oversight of the data collection.  The PI will follow the Data Safety and 
Monitoring plan outlined in the Sidney Kimmel Comprehensive Cancer Center’s DSMP Policy.   
 
9.1. Data Reporting 
 The SKCCC Compliance Monitoring Program will provide external monitoring for JHU-affiliated 
sites in accordance with SKCCC DSMP (Version 6.0, 02/21/2019). The SMC Subcommittee will 
determine the level of patient safety risk and level/frequency of monitoring. 
The PI is responsible for monitoring the study.  Data must be reviewed to assure the validity of 
the data, as well as the safety of the subjects.  The PI will also monitor the progress of the trial, 
review safety reports, and clinical trial efficacy endpoints and to confirm that the safety 
outcomes favor continuation of the study.  The PI will be responsible for maintaining the clinical 
protocol, reporting adverse events, assuring that consent is obtained and documented, reporting 
of unexpected outcomes, and reporting the status of the trial in the continuing renewal report 
submitted to the IRB and to the monitoring review group. The report should be submitted in a 
timely manner according to the schedule defined by the Johns Hopkins Medicine Institutional 
Review Board. 
 
9.2. Management of Safety Data 
This Study has been designated as an interventional study.  As such, all adverse events/product 
quality complaints for study drug (flotetuzumab) regardless of causality and special situations 
will be reported from the time a subject has signed an Informed Consent Form (ICF) until 30 
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Serious adverse events will be reported for 30 days after the last dose of study drug. 
 
9.3. Adverse Event Definition 
An adverse event is any untoward medical occurrence in a clinical study subject administered a 
medicinal (investigational or non-investigational) product. An adverse event does not necessarily 
have a causal relationship with the treatment. An adverse event can therefore be any unfavorable 
and unintended sign (including an abnormal finding), symptom, or disease temporally associated with 
the use of a medicinal (investigational or non- investigational) product, whether or not related to that 
medicinal (investigational or non-investigational) product. (Definition per International Conference on 
Harmonisation [ICH]) 
This includes any occurrence that is new in onset or increased in severity or frequency from the 
baseline condition, or abnormal results of diagnostic procedures, including laboratory test 
abnormalities (except Grade 1 and 2 hematologic and metabolic abnormalities) that are deemed 
clinically significant by the principal investigator.  
 
This study will utilize the Common Terminology Criteria for Adverse Events (CTCAE) version 
5.0 for adverse event reporting, except for IRR/CRS, which has been defined in Table 4.  In 
cases where CTCAE version 5.0 cannot be applied to the toxic event, the investigator will 
quantify the toxicity based on the intensity as defined: 
 
1. Mild: The subject is aware of the signs or symptoms but they are easily tolerated; 
usually does not require additional therapy or discontinuation of study drugs. 
2. Moderate:  The signs and symptoms are sufficient to restrict but do not prevent usual 
activity; possibly requires additional therapy but usually does not require discontinuation 
of the study drug. 
3. Severe:  The subject is unable to perform usual activities and usually requires 
discontinuation of the study drug. 
 
Patients are to be followed for adverse events for 30 days after the last dose of the study drug 
and any adverse event occurring in a patient up to 30 days after stopping the study drug or until 
the start of a subsequent systemic anticancer therapy, if earlier, must be reported.  The 
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suspicion that the drug has not yet been eliminated or if the nature of a particular event may 
suggest long-term effects from the investigational drug, as assessed by the investigator. 
 
9.4. Serious Adverse Event (SAE) Definition 
A serious adverse event based on ICH and EU Guidelines on Pharmacovigilance for Medicinal 
Products for Human Use is any untoward medical occurrence that at any dose: 
 
• 
Results in death 
• 
Is life-threatening (The subject was at risk of death at the time of the event. It does not 
refer to an event that hypothetically might have caused death if it were more severe.) 
• 
Requires inpatient hospitalization or prolongation of existing hospitalization 
• 
Results in persistent or significant disability/incapacity 
• 
Is a congenital anomaly/birth defect 
• 
Is a suspected transmission of any infectious agent via study drug 
• 
Is medically important determined by the investigator(s)* 
 
*The investigator should exercise medical and scientific judgment in deciding whether expedited 
reporting is also appropriate in other situations, such as important medical events that may not 
be immediately life threatening or result in death or hospitalization but may jeopardize the 
subject or may require intervention to prevent one of the other outcomes listed in the definition 
above. These should usually be considered serious. 
 
NOTE: DEATH FOR ANY REASON SHOULD BE REPORTED AS A SERIOUS ADVERSE 
EVENT. 
 
9.4.1. Hospitalization or prolongation of existing hospitalization following the completion of 
flotetuzumab 
For reports of hospitalization, it is the sign, symptom or diagnosis which led to the hospitalization that 
is the serious event for which details must be provided. In the event of prolongation of an already 
existing hospitalization, the event that triggered the increased hospital stay will be considered as 
SAE.  
Any event requiring hospitalization or prolongation of hospitalization that occurs during the study 
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• 
Hospitalizations not intended to treat an acute illness or adverse event (e.g., social reasons 
such as pending placement in long-term care facility) 
• 
Surgery or procedure planned before entry into the study. [Note: Hospitalizations that 
were planned before the start of data collection and where the underlying condition for 
which the hospitalization was planned has not worsened will not be considered serious 
adverse events. Any adverse event that results in a prolongation of the originally 
planned hospitalization is to be reported as a new serious adverse event.] 
• 
The investigator will be required to hospitalize the subject for the duration of the 
treatment period.  
9.4.2. Life-Threatening Conditions 
An AE or SAE is considered “life-threatening” if, in the view of the Investigator, its occurrence 
places the subject at immediate risk of death. It does not include an AE or SAE that, had it 
occurred in a more severe form, might have caused death. 
Disease progression should not be recorded as an adverse event or serious adverse event 
term; instead, signs and symptoms of clinical sequelae resulting from disease progression/lack 
of efficacy will be reported if they fulfill the serious adverse event definition. 
9.5. Unexpected (unlisted) Adverse Event/Reference Safety Information 
An adverse event is considered unexpected if the nature or severity is not consistent with the 
applicable product reference safety information. For a medicinal product(s) with a marketing 
authorization, the expectedness of an adverse event will be determined by whether or not it is 
listed in the applicable product information.  
 
For flotetuzumab, the expectedness of an adverse event will be determined by whether or not it 
is listed in the Investigator’s Brochure.  Any unexpected clinical event, regardless of grade 
requires expedited reporting to the regulatory authorities.  
 
9.6. Adverse Drug Reaction and Toxicity Monitoring 
The study team (research nurse, study coordinator or attending) will assign toxicity scores using 
the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, weekly through 
the first cycle of therapy and at least every cycle thereafter.  A copy of the CTCAE version 5.0 is 
available at 
(https://ctep.cancer.gov/protocoldevelopment/electronic_applications/docs/ctcae_v5_quick_refer

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ence_5x7.pdf).  If unexpected and serious toxicity occurs that would result in patients being 
subjected to unacceptable risk, the trial will be placed on hold while the toxicity is investigated. 
 
9.7. Toxicity Reporting 
The Principal Investigator is responsible for ongoing safety evaluation of the study. The 
Principal Investigator is required to notify his/her Institutional Review Board (IRB) of a serious 
adverse event according to institutional policy. The requirements for IRB Protocol Problem 
Reporting at Johns Hopkins are can be found at this website: 
http://www.hopkinsmedicine.org/institutional_review_board/guidelines_policies/guidelines/ 
 
FDA reporting requirements 
7 Calendar-Day IND Safety Report 
Fatal or life threatening SAEs that meet the criteria for reporting to the FDA must be reported to 
the FDA within 7 calendar days after awareness of the event. Serious adverse events (SAEs) 
that are unexpected, and at least possibly associated to the study drugs, as assessed by the 
Investigator, should be reported promptly to the Food and Drug Administration (FDA).  
 
15 Calendar-Day Written IND Safety Report 
The Investigator is required to notify the FDA, and all participating investigators in a written IND 
Safety Report, of any serious, unexpected adverse event considered by the Investigator to be 
possibly related to the use of study drugs within 15 calendar-days of first learning of the event. If 
applicable, the Investigator must also notify the FDA, and all participating investigators, of any 
finding from tests in laboratory animals that suggests a significant risk for human subjects 
including reports of mutagenicity, teratogenicity, or carcinogenicity within 15 calendar-days of 
first learning of the event. 
 
All other SAEs that meet the criteria for reporting to the FDA must be reported to the FDA 
within 15 calendar days after awareness of the event. A clear description of the suspected 
reaction should be provided along with an assessment as to whether the event is drug or 
disease related. 
 
All IND safety reports must be submitted to the FDA on Form 3500A and be accompanied by 
Form 1571. The report must be submitted to an appropriate Review division that has the 
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safety reports are recommended to be submitted electronically. Other means of rapid 
communication to the respective review divisions Regulatory Project Manager (e.g., telephone, 
facsimile transmission, email) may also be used.  
 
 
Reporting Protocol Deviations to the JHM IRB  
There are several types of deviations from protocol procedures recognized by the JHM IRB, and 
each type has a different IRB reporting requirement: 
A. Protocol deviations that constitute unanticipated problems involving risks require prompt 
reporting to the JHM IRB: A protocol deviation that constitutes an “unanticipated problem 
involving risks to subjects or to others” (Policy No. 103.6(b) for the definition of an unanticipated 
problem) must be reported promptly to the IRB, as follows: 
1. Emergency deviations: When a deviation occurs in an emergency situation, such as 
when a departure from the protocol is required to protect the life or physical well-being of 
a participant. The Sponsor (JHU Principal Investigator) and the reviewing IRB must be 
notified as soon as possible, but not later than 5 days after the emergency situation 
occurred (21 CFR 812.150(a)(4)).  
2. Major, non-emergent deviations without prior approval: A planned deviation that is 
non-emergent and represents a major change in the protocol as approved by the IRB. 
The Principal Investigator and the IRB must approve the request before the proposed 
change is implemented. If a major, non-emergent deviation occurs without prior IRB 
approval the event is considered non-compliance. Noncompliance must be reported to 
the IRB promptly. 
B. Protocol deviations that are only minor or administrative: At JHM, minor or administrative 
protocol deviations are defined as those which do not “affect the scientific soundness of the 
research plan or the rights, safety, or welfare of human subjects.” If a protocol deviation occurs 
which meets this definition, the deviation should be reported to the JHM IRB at the time the 
continuing review application is submitted. Examples of minor or administrative deviations 
could include: follow up visits that occurred outside the protocol required time frame 
because of the participant’s schedule, or blood samples obtained at times close to but not 
precisely at the time points specified in the protocol. 
 
 

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9.7.1. Special Reporting Situations 
Safety events of interest for a Macrogenics medicinal product that require expediting reporting 
and/or safety evaluation include, but are not limited to: 
• 
Drug exposure during pregnancy (maternal and paternal) 
• 
Overdose of a Macrogenics medicinal product  
• 
Exposure to a Macrogenics medicinal product from breastfeeding  
• 
Suspected abuse/misuse of a Macrogenics medicinal product 
• 
Inadvertent or accidental exposure to a Macrogenics medicinal product  
• 
Any failure of expected pharmacological action (i.e., lack of effect) of a Macrogenics 
medicinal product 
• 
Medication error involving a Macrogenics medicinal product (with or without patient 
exposure to the Macrogenics medicinal product, e.g., name confusion) 
• 
Suspected transmission of any infectious agent via administration of a medicinal product 
• 
Unexpected therapeutic or clinical benefit from use of a Macrogenics medicinal product 
 
These safety events may not meet the definition of an adverse event; however, from a 
Macrogenics Scientific Affairs, LLC perspective, they are treated in the same manner as 
adverse events. Special situations should be recorded on the Adverse Event page of the CRF. 
 
Any special situation that meets the criteria of a serious adverse event should be recorded on a 
Serious Adverse Event Report Form and be reported to Macrogenics Scientific Affairs, LLC 
within 24 hours of the submission to regulatory authorities. 
 
9.7.2. SAEs  
All serious adverse events that have not resolved by the end of the study, or that have not 
resolved upon discontinuation of the subject's participation in the study, must be followed until 
any of the following occurs: 
• 
The event resolves 
• 
The event stabilizes 
• 
The event returns to baseline, if a baseline value/status is available 
• 
The event can be attributed to agents other than the study drug or to factors unrelated to 
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• 
It becomes unlikely that any additional information can be obtained (subject or health care 
practitioner refusal to provide additional information, lost to follow-up after demonstration of 
due diligence with follow-up efforts) 
 
The principal investigator will transmit all SAEs and special situations following exposure to a 
Macrogenics product under study in a form provided by Macrogenics Scientific Affairs, LLC in 
accordance with Section 9.11.4 Transmission Methods, in English within 24-hours of the 
submission to regulatory authorities. 
 
All follow-up information for serious adverse events that are not resolved at the end of the study 
or by the time of patient withdrawal must be reported directly by the principal investigator, 
within 24 hours of the submission to regulatory authorities, to Macrogenics Scientific 
Affairs, LLC using the Macrogenics Scientific Affairs, LLC Serious Adverse Event Report. 
 
All available clinical information relevant to the evaluation of a related SAE, serious ADR or special 
situation is required. 
 
• 
The principal investigator is responsible for ensuring that these cases are complete and if not are 
promptly followed-up. A safety report is not considered complete until all clinical details needed to 
interpret the case are received. Reporting of follow-up information should follow the same 
timeline as initial reports. 
 
• 
Copies of any and all relevant correspondences with regulatory authorities and ethics committees 
regarding any and all serious adverse events, irrespective of association with the Macrogenics 
Product under study, are to be provided to Macrogenics Scientific Affairs, LLC using a 
transmission method in Section 9.11.4. 
 
9.7.3 Non-Serious AEs 
All non-serious adverse events should be reported to Macrogenics Scientific Affairs, LLC 
according to the timeframe agreed between all involved parties. 
 

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9.8. Pregnancies 
All initial reports of pregnancy must be reported to Macrogenics Scientific Affairs, LLC by the 
principal investigator within 24 hours of the submission to regulatory authorities using the 
Serious Adverse Event Form. Abnormal pregnancy outcomes (e.g. spontaneous abortion, fetal 
death, stillbirth, congenital anomaly, ectopic pregnancy) are considered serious adverse events 
and must be reported using the Serious Adverse Event Form.  
Any subject who becomes pregnant during the study must be promptly withdrawn from the 
study and discontinue further study treatment. 
 
Because the effect of the Macrogenics medicinal product on sperm is unknown, pregnancies in 
partners of male subjects exposed to a Macrogenics medicinal product will be reported by the 
principal investigator within 24 hours of the submission to regulatory authorities using the 
Serious Adverse Event Form.   
Follow-up information regarding the outcome of the pregnancy and any postnatal sequelae in 
the infant will be required. 
 
9.9. Drug Relationship 
The investigator will classify the study product relationship of an adverse event to the 
investigational product according to the following definition: 
1. None:  The time course between the administration of the study product and the 
occurrence or worsening of the adverse event rules out a causal relationship and or 
another cause is confirmed and no indication of involvement of the study product in the 
occurrence/worsening of the adverse event exists. 
2. Unlikely:  the time course between the administration of the study product and the 
occurrence or worsening of the AE makes a causal relationship unlikely; the known 
product effects of the study product or of the substance class provide no indication of 
involvement in the AE and another cause adequately explains the AE; regarding the AE, 
a plausible causal chain may be deduced from the known side effects of the study 
product or the substance class but another cause is much more probably; or another 
cause is confirmed and involvement of the study product in the AE is unlikely. 
3. Possible:  Regarding the AE, a plausible causal chain may be deduced from the 
pharmacological properties of the study product or the substance class, but another 
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properties of the study product or the substance class provide no indication of 
involvement in the AE, no other cause gives adequate explanation. 
4. Probable:  the pharmacological properties of the study product or of the substance 
class and/or the course of the AE suggest involvement of the study product in the AE, 
although another cause cannot be ruled out. 
5. Definite:  the pharmacological properties of the study product or of the substance 
class and the course of the AE indicate involvement of the study product in the AE and 
no indication of other causes exists. 
6. Unclassifiable:  only used for SAE:  the available information is not sufficient for 
causality assessment. 
9.10. Outcome 
The investigator will record the outcome of the AE choosing one of the following categories: 
1. Recovered/resolved 
2. Recovering/resolving 
3. Not recovered/not resolved 
4. Recovered/resolved with residual effects as specified 
5. Fatal 
6. Unknown 
 
9.11. Data Handling and Record Keeping 
9.11.1. Maintenance of Safety Information 
All safety data should be maintained in a clinical database in a retrievable format. The principal 
investigator shall provide all adverse events, both serious and non-serious, in report format. 
However, in certain circumstances more frequent provision of safety data may be necessary, e.g. to 
fulfill a regulatory request, and as such the data shall be made available within a reasonable 
timeframe at Macrogenics Scientific Affairs, LLC request. 
 
9.11.2. Procedures for Reporting Safety Data and Product Quality Complaints (PQCs) for 
Macrogenics Medicinal Products to Macrogenics Scientific Affairs, LLC 
All adverse events and special situations, whether serious or non-serious, related or not related, 
following exposure to a Flotetuzumab are to be documented by the investigator and recorded in 
the CRF and in the subject’s source records. Investigators must record in the CRF their opinion 
concerning the relationship of the adverse event to Flotetuzumab.  

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All (serious and non-serious) adverse events reported for Flotetuzumab should be followed-up 
in accordance with clinical practice. 
 
9.11.3. Reporting Procedures for Reporting Safety Data and Product Quality Complaints 
(PQCs) for Non-Macrogenics Medicinal Products 
For SAEs, special reporting situations and PQCs following exposure to a non-Macrogenics 
medicinal product under study, the principal investigator should notify the appropriate 
regulatory/competent authority or the manufacturer of that medicinal product (in the absence of 
appropriate local legislation) as soon as possible. 
9.11.4. Transmission Methods 
The following methods are acceptable for transmission of safety information to Macrogenics Scientific 
Affairs, LLC: 
• 
Electronically via Macrogenics SECURE Email service (preferred), For business continuity 
purposes, if SECURE Email is non-functional: 
o 
Facsimile (fax), receipt of which is evidenced in a successful fax transmission report, to  
• 
Telephone (if fax is non-functional). 
 
Please use the contact information and process information provided by Macrogenics Scientific 
Affairs, LLC. The report will be submitted to MacroGenics Product Safety via: 
Fax: 301.354.3800 OR 
Email: saereports@MacroGenics.com 
10. Ethics 
10.1. Institutional Review Board 
The study protocol and any amendment that is not solely of an administrative nature must be 
approved by an Institutional Review Board (IRB). 
 
10.2. Ethical Conduct of the Study 
The study will be conducted in accordance with the ethical principles of the Declaration of 
Helsinki. 
 

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10.3. Evaluation of Benefits and Risks/Discomforts 
10.3.1. Potential Benefits 
Patients will receive evaluation and treatment of their malignancy as a result of participating in 
this trial.  The trial will provide information on the safety of administering flotetuzumab to 
patients following alloHSCT but may or may not help a specific patient personally.  This 
treatment may enhance relapse free survival compared to alloHSCT alone.  Alternative 
approaches to entering this trial, including standard supportive care only, will also be discussed 
before the verbal and written consent is obtained regarding the risks, benefits, and the treatment 
requirements for this trial. 
 
10.3.2. Measure for Minimizing Risk 
Administering flotetuzumab to patients may involve risks that are currently unforeseeable.  Side 
effects can be unpredictable in nature and severity, although all care will be taken to minimize 
them.  If patients suffer any physical injury as a result of participating in this study, immediate 
medical treatment is available at the treatment center.  Frequent blood work will be taken to 
monitor side effects.  Although no compensation is available, any injury will be evaluated and 
treated in keeping with benefits of care to which patients are entitled under applicable 
regulations.  Patients may experience significant treatment-related morbidity, and/or progression 
of their disease. 
 
10.3.3. Risks/Benefits Analysis 
Data gathered from both clinical and laboratory evaluations in this trial will be analyzed 
frequently to ensure safety of the patients.  Any new or significant finding(s) found during the 
course of the research will be shared and explained to each participant since that may affect a 
patient’s willingness to participate further.  Patient’s anonymity will be protected to the maximum 
extent in all publications and presentations that result from research. 
 
10.3.4. Patient Information and Consent 
The investigator or consent designee will explain the nature of the study, its purpose and 
associated procedures, the expected duration, and the potential benefits and risks of 
participation to each patient prior to his/her entry into the study (i.e. before examinations and 
procedures associated with selection for the study are performed).  Each patient will have ample 
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any time without any disadvantage and without having to provide reasons for this decision.  
Following this informative discussion, a patient will be asked if he/she is willing to sign and 
personally date a statement of informed consent.  Only if the patient voluntarily agrees to sign 
the informed consent statement and has done so, may he/she enter the study.  The patient will 
receive a copy of the signed and dated informed consent form.  The signed informed consent 
statement is to remain in the investigator’s files.  The informed consent form and any other 
written information provided to the patients will be revised whenever important new information 
becomes available that may be relevant to the patient’s consent, or there is an amendment to 
the protocol which necessitates a change to the content of the written informed consent form.  
The investigator will inform the patient of changes as per IRB recommendations in a timely 
manner and will ask the patient confirm continuation of his/her participation in the study by 
his/her signature on the revised informed consent form.  Any revised written informed consent 
form must receive the IRB’s approval/favorable opinion in advance of use. 
 
10.4. Financial Disclosure 
Each investigator (including the principal investigator and any sub-investigators) who is directly 
involved in the treatment or evaluation of research subjects must disclose certain financial 
arrangements.  A financial disclosure statement must be provided for each investigator 
(including each sub-investigator in IND studies identified on FDA Form 1572) at a study site. 
 
The following arrangements with, and interests of, investigators (including the spouse and 
dependent children) should be disclosed to the FDA: 
1. Compensation made to the investigator in which the value of compensation could be 
affected by study outcome (e.g. higher compensation for favorable outcome than for 
an unfavorable outcome, or a royalty interest related to product sales). 
2. A proprietary interest by the investigator in the tested product, including, but not 
limited to, a patent, trademark, copyright or licensing agreement 
3. Any equity interest in the study supporter, Macrogenics Scientific Affairs, LLC (i.e. 
any ownership interest, stock options, or other financial interest whose value cannot 
be readily determined through reference to public prices, or any equity interest in a 
publicly held company that exceeds $50,000 in value held during the time the 
investigator is carrying out the study and for 1 year following completion of the study) 
4. Significant payments of other sorts, i.e., payments that have a cumulative monetary 
value of $25,000 or more, made by the study supporter (Macrogenics Medical 

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Affairs, LLC) of a covered study to the investigator or the investigator’s institution to 
support activities of the investigator exclusive of the costs of conducting the clinical 
study or other clinical studies (e.g., a grant to fund ongoing research, compensation 
in the form of equipment or retainers for ongoing consultation or honoraria) during 
the time the investigator is carrying out the study and for 1 year following completion 
of the study 
5. In this context “investigator” is defined as all individuals listed on FDA form 1572 – or 
for non-IND studies performed outside the U.S. listed in the signature list. 
6. This shall also apply to the spouse and each dependent child of the investigator.  
 
 
 

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29. Miyazaki T, Fujita H, Fujimaki K, et al. Clinical significance of minimal residual disease 
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37. Litzow MR, Tarima S, Perez WS, et al. Allogeneic transplantation for therapy-related 
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38. Sengsayadeth S, Gatwood KS, Boumendil A, et al. Conditioning intensity in secondary AML 
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39. Burnett AK, Goldstone A, Hills RK, et al. Curability of patients with acute myeloid leukemia 
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hematopoietic cell transplantation for the treatment of high-risk acute lymphoblastic leukemia. 
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42. Brissot E, Labopin M, Beckers MM, et al. Tyrosine kinase inhibitors improve long-term 
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43. Chen YB, Li S, Lane AA, et al. Phase I trial of maintenance sorafenib after allogeneic 
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acute myeloid leukemia. Biol Blood Marrow Transplant. 2014;20(12):2042-2048. 

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44. Khouri IF, McLaughlin P, Saliba RM, et al. Eight-year experience with allogeneic stem cell 
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46. LaPort GG, Wu J, Logan BR, et al. Reduced intensity conditioning (RIC) with rituximab 
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2015;21(12):2115-2122. 
 
 
 

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12. Appendix 
12.1. GVHD Staging and Grading 
 
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Mild chronic GVHD 
1 or 2 Organs involved with no more than score 1 plus 
Lung score 0 
 
Moderate chronic GVHD 
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OR 
At least 1 organ (not lung) with a score of 2 
OR 
Lung score 1 
 
Severe chronic GVHD 
At least 1 organ with a score of 3 
OR 
Lung score of 2 or 3 
 
Key points: 
In skin: higher of the 2 scores to be used for calculating global severity. 
In lung: FEV1 is used instead of clinical score for calculating global severity. 
If the entire abnormality in an organ is noted to be unequivocally explained by a non-
GVHD documented cause, that organ is not included for calculation of the global 
severity. 
If the abnormality in an organ is attributed to multifactorial causes (GVHD plus other 
causes) the scored organ will be used for calculation of the global severity regardless of 
the contributing causes (no downgrading of organ severity score).