bone marrow transplantation vs standard of care in patients with severe sickle cell disease (bmt ctn 1503)

Conditions: Sickle Cell Disease

Summary: this is a clinical trial that will compare survival and sickle related outcomes in adolescents and young adults with severe sickle cell disease after bone marrow transplantation and standard of care. the primary outcome is 2-year overall survival.

this is a prospective phase ii multi-center trial of hematopoietic stem cell transplantation or standard of care based on availability of hla-matched related or unrelated donor after confirmation of clinical eligibility. in order to minimize bias assignment to either treatment arm, clinical eligibility to both treatment arms are similar and donor availability is not known at referral. hla typing and donor search is initiated upon confirmation of clinical eligibility for the study. additionally, all analyses of primary and secondary endpoints will follow the intent-to-treat principle to address potential bias introduced by participants with donors not proceeding to transplantation or those without a matched donor receiving transplantation with less well-matched donors. the primary outcome is 2-year overall survival. our hypothesis is that patients who receive bone marrow transplantation will experience early deaths but that this will plateau by 2 years after transplantation. patients who receive standard of care will not experience early death but will succumb to their disease at a rate much higher than the general population. therefore, the goal of the study is to establish that the difference in the proportion of patients surviving is not significantly more than 15% lower in the donor arm at 2-years after assignment to treatment arm. secondary endpoints will compare changes in sickle cell disease related events (pulmonary hypertension, cerebrovascular events, renal function, avascular necrosis, leg ulcer) and functional outcomes \[6-minute walk distance (6mwd), health-related quality of life, cardiac function, pulmonary function, and mean pain intensity as assessed by a multidimensional electronic pain diary\] from baseline to 2-years after assignment to treatment arms. additionally for patients assigned to the donor arm and expected to undergo transplantation, hematopoietic recovery, graft rejection, acute and chronic graft-versus-host disease, other significant transplant-related complications and disease-free survival will be reported.

Eligibility criteria:
inclusion criteria: 1. age ≥ 15 and \< 41 years 2. severe sickle cell disease \[hemoglobin ss (hb ss), hemoglobin sc (hb sc) or hemoglobin sbeta thalassemia (hb sβ) genotype\] with at least 1 of the following manifestations (a-e): 1. clinically significant neurologic event (stroke) or any neurological deficit lasting \> 24 hours; 2. history of two or more episodes of acute chest syndrome (acs) in the 2-year period preceding enrollment despite the institution of supportive care measures (i.e. asthma therapy); 3. an average of three or more pain crises per year in the 2-year period preceding enrollment (required intravenous pain management in the outpatient or inpatient hospital setting). clinical documentation of pain management in the inpatient or outpatient setting is required. 4. administration of regular rbc transfusion therapy, defined as receiving 8 or more transfusion events per year (in the 12 months before enrollment) to prevent vaso-occlusive clinical complications (i.e. pain, stroke, and acute chest syndrome) 5. an echocardiographic finding of tricuspid valve regurgitant jet (trj) velocity ≥ 2.7 m/sec. 6. ongoing high impact chronic pain on a majority of days per month for ≥ 6 months as defined as one or more of the following: chronic pain without contributory scd complications, or mixed pain type in which chronic pain is occurring at site(s) (arms, back, chest, or abdominal pain) unrelated to any sites associated with contributory scd complications (e.g. leg ulcers and/or avascular necrosis). i. high impact chronic pain is identified as those reporting "severe interference" with life activities or "usually or always" experiencing a limitation of their life or work activities including household chores. (see guidelines for identifying hicp in the bmt ctn 1503 manual of procedures) ii. contributory scd complications are defined as clinical signs (e.g. presence of leg ulcers) or clinical assessments (e.g. imaging confirmation of splenic infarct or avascular necrosis). chronic pain attributed solely to contributory scd complications is excluded. 3. adequate physical function as measured by all of the following: 1. karnofsky/lansky performance score ≥ 60 2. cardiac function: left ventricular ejection fraction (lvef) \> 40%; or lv shortening fraction \> 26% by cardiac echocardiogram or by multi gated acquisition scan (muga). 3. pulmonary function: a. pulse oximetry with a baseline o2 saturation of ≥ 85% b. diffusing capacity of the lung for carbon monoxide (dlco) \> 40% (corrected for hemoglobin) d. renal function: serum creatinine ≤ 1.5 x the upper limit of normal for age as per local laboratory and 24 hour urine creatinine clearance \>70 ml/min; or gfr \> 70 ml/min/1.73 m2 by radionuclide glomerular filtration rate (gfr). e. hepatic function: 1. serum conjugated (direct) bilirubin \ 2x the upper limit of normal for age as per local laboratory and: there is evidence of a hyperhemolytic reaction after a recent rbc transfusion, or there is evidence of moderate direct hyperbilirubinemia defined as direct serum bilirubin \< 5 times uln and not caused by underlying hepatic diseasepatients 2. alanine aminotransferase (alt) and aspartate aminotransferase (ast) \< 5 times upper limit of normal as per local laboratory. additional inclusion required for donor arm participants to proceed with transplant 1. liver mri (≤ 90 days prior to initiation of transplant conditioning) to document hepatic iron content is required for participants who are currently receiving ≥8 packed red blood cell transfusions for ≥1 year or have received ≥20 packed red blood cell transfusions (cumulative). participants who have hepatic iron content ≥7 mg fe/ g liver dry weight by liver mri must have a liver biopsy and histological examination/documentation of the absence of cirrhosis, bridging fibrosis and active hepatitis (≤ 90 days prior to initiation of transplant conditioning). 2. lack of clinical or radiologic evidence of a recent neurologic event (such as stroke or transient ischemic attack) by cerebral mri/mra within 30 days prior to initiating transplant conditioning. subjects with clinical or radiologic evidence of a recent neurologic event will be deferred for ≥ 6 months with repeat cerebral mri/mra to ensure stabilization of the neurologic event prior to proceeding to transplantation 3. documentation of participant's willingness to use approved contraception method until discontinuation of all immunosuppressive medications is to be documented in the medical record corresponding with the consent conference. exclusion criteria: 1. hla typing with a donor search prior to referral (consultation with hct physician). 1. if a subject has had hla typing and a related donor search that did not identify a suitably matched relative (i.e., sibling) at any time, and also did not have an unrelated donor search, the patient will be considered eligible. 2. if a subject has had hla typing and a related donor search that did not identify a suitably matched relative (i.e., sibling) at any time and had an unrelated donor search that did not identify a suitably matched unrelated donor ≥ 1 year prior to enrollment, the patient will be considered eligible. 3. if a subject has had hla typing with no related donor search and had an unrelated donor search that did not identify a suitably matched unrelated donor ≥ 1 year prior to enrollment, the patient will be considered eligible. 4. subjects with a known hla-identical sibling or hla-matched unrelated donor are excluded 2. uncontrolled bacterial, viral or fungal infection in the 6 weeks before enrollment. 3. seropositivity for hiv. 4. previous hct or solid organ transplant. 5. participation in a clinical trial in which the patient received an investigational drug or device must be discontinued at enrollment. 6. a history of substance abuse as defined by version iv of the diagnostic \& statistical manual of mental disorders (dsm iv). 7. demonstrated lack of compliance with prior medical care as determined by referring physician. 8. pregnant or breast feeding females. 9. inability to receive hct due to alloimmunization, defined as the inability to receive packed red blood cell (prbc) transfusion therapy.

Keywords: sickle cell disease young adults phase ii trial hematopoietic cell transplantation (hct) human leukocyte antigen (hla)