Outcome of STRIDE Pilot Study and Study Design of BMT CTN 1503

STRIDE Pilot study of HCT for Young Adults with SCD: Introduction EFS is ~90-95% after HLA-ID sibling HCT in pediatricSCD Toxicity observed after HCT in adults with SCD in early trials limited its therapeutic application HLA-ID sib HCT in adults with SCD using non-myeloablative conditioning effective, but alternate donor HCT will require higher intensity prep (Hsieh et al 2014) Bu+Flu+ATG conditioning effective in URD HCT for Thalassemia, AML Is HCT with Bu+Flu+ATG in adults with SCD safe and effective?

STRIDE Pilot Study Design Pilot Study of HCT for Adults with SCD Test safety and efficacy of conditioning regimen and plan larger multicenter dual arm trial to compare HCT and regular care Objective Determine if HCT in patients aged 16-40 years with severe SCD will result in 1-year disease-free survival ≥75% Primary endpoint: 1 year event free survival Events : Graft failure, Disease Recurrence, Death Secondary endpoints Donor Chimerism, Transplant related toxicities SCD related complications NHLBI 1R34-HL108761-01

Inclusion Criteria SCD (any genotype), Ages 16-40 years with 8/8 HLA-allele matched sib/unrelated donor Severe disease defined as having 1 or more of the following: Clinically significant neuro event or deficit lasting > 24 hrs ≥ 2 episodes ACS in last 2-yrs despite supportive care ≥ 3 severe VOCs/yr in last 2-yrs despite supportive care ≥ 8 RBC transfusion/year TRJ velocity ≥ 2.7 m/sec

Conditioning Regimen BMT Flu 35mg/m2/day Bu 3.2/kg/day rATG total 6 mg/kg -8 -7 -6 -5 -4 -3 -2 -1 0 1 3 6 11 100 180 Methotrexate Tacro or CsA

Patient Characteristics and Study Timeline Gender Female 13, Male 9 Median Age ( Range) in years 22( 18-36) Indication for HCT n VOC 17 Chronic transfusion 6 TRJ velocity>2.7 5 Single indication 11 more than 1 indication Donor Type Sibling 17, unrelated 5 Participating Institutions Children’s Healthcare of Atlanta, GA Children’s Hospital of Oakland, CA Children’s Hosp Pittsburgh, PA Children’s National Medical Center City of Hope, CA Duke University Medical Center Emory University, Atlanta, GA Virginia Commonwealth Univ Study Timeline 4 patients transplanted 6 months observation 1 year follow up 18 patients transplanted Jul ‘12-Apr ‘13 May ‘13-Oct’13 Nov ‘13-Jul ‘15 Jul ‘15-Jul ‘16

Survival and HCT Outcomes in 22 Patients OS and EFS (median follow up 13.6 months): 90 % N(%) Grade II-IV AGVHD: 4(18) Moderate CGVHD: 3(13) Severe CGVHD: 1(4) Deaths: 2 PRES/intracranial bleed( 1), GVHD(1) Bacteremia: 10 Viral reactivation: 10 Overall Survival Time (mos after BMT)

High RBC Chimerism Despite Partial Lymphoid Chimerism Mean Percentage Donor Chimerism d+28 d+100 d+180 d+360 Median Percentage Donor Chimerism ( Range) D +28 D +100 D+180 D+365 RBC 100 (89-100) n=22 (24-100) n=20 (93-100) n-14 91 (79-100) n=11 Lymphoid Chimerism 55.5 (12-100) n=21 80.5 (10-100) 88.5 (11-100) n-16 81.5 n=13

High RBC Chimerism Despite Partial Lymphoid Chimerism RBC chimerism assayed by pyrosequencing of the sickle cell mutation Quantifies relative levels of normal and sickle beta globin mRNA Mixed lymphoid chimerism despite myeloablative therapy ? Impact of rATG Lymphoid chimerism increases over time RBC chimerism remains high despite low lymphoid chimerism Hb Electrophoresis demonstrates complete donor erythropoiesis in all patients.

Conclusions Future Directions Bu/Flu/ATG conditioning is safe in eligible young adults with SCD No graft rejection and low rates of GVHD We observed 90% EFS after HLA-matched HCT No pain or SCD related events after 180 days Future Directions Conduct a larger trial of HCT with donor and no donors cohorts and compare survival Impact of donor erythropoiesis on SCD phenotype

Hematopoietic Cell Transplantation for Young Adults with Severe Sickle Cell Disease BMT CTN 1503 Drs. Krishnamurti, Walters, Sullivan, Neuberg, Mendizabal and Eapen for the Protocol Team

Specific Aims – BMT CTN 1503 Specific Aim 1 Determine the tolerability and efficacy of HCT in adolescents and young adults with severe SCD The difference in 2 year overall survival between HCT recipients and those receiving standard of care should not exceed 15% (i.e., the donor vs. no-donor arms of the proposed trial) Specific Aim 2 Measure the benefit of donor hematopoiesis on sickle-related events, organ function (pulmonary, renal), health related quality of life and pain assessments (via e-diary)

Eligibility Criteria – BMT CTN 1503 Age 15 – 40 years CNS event: stroke or deficit lasting >24 hours ≥ 2 episodes of acute chest syndrome (ACS) in preceding 2 years despite adequate supportive care measures ≥ 3 episodes of pain crisis (VOC) in preceding 2 years despite adequate supportive care measures ≥ 8 transfusions per year for ≥ 1 year to prevent SCD-related complications (VOC, ACS, stroke) Tricuspid valve regurgitant jet (TRJ) ≥ 2.7 m/sec

Study Design: Intent-to-Treat Analysis Consultation with HCT physician Not Eligible ERC: Confirm Clinical Eligibility HLA typing Re-register in AdvantageEDCSM for Biologic Assignment Off study Donor No Donor HCT Comparison Cohort HCT not Performed Clinically Eligible; Consent Register in AdvantageEDCSM vs. ITT Analysis *

Study Design Donor arm (N=60); No donor arm (N=140) Patients with ERC confirmed eligibility will be HLA typed and donor search initiated HLA typing with donor search before referral = INELIGIBLE for BMT CTN 1503 Biologic assignment occurs 60 +/- 30 days after re-registration to AdvantageEDC Start time: Biologic Assignment Follow up: 3 years from Biologic Assignment (3rd year follow-up by CIBMTR)

Donor/Graft Selection – BMT CTN 1503 Bone marrow grafts ONLY Target TNC 2-4 x 108/kg patient weight Donors Sibling: HLA-matched Unrelated adult donor matched to patient at the allele-level at HLA-A, -B, -C, -DRB1 All donors will be screened for sickle cell / thalassemia – trait acceptable Screen for donor specific HLA-antibodies

Conditioning Regimen – BMT CTN 1503 Day Regimen -8 IV busulfan 3.2 mg/kg -7 IV busulfan 3.2 mg/kg, fludarabine 35 mg/m2 -6 IV busulfan 3.2 mg/kg, fludarabine 35 mg/m2, thymoglobulin 0.5 mg/kg -5 IV busulfan 3.2 mg/kg, fludarabine 35 mg/m2, thymoglobulin 1 mg/kg -4 IV fludarabine 35 mg/m2, thymoglobulin 1.5 mg/kg -3 -2 IV thymoglobulin 1.5 mg/kg -1 Rest Infuse bone marrow graft

GVHD prophylaxis – BMT CTN 1503 Day Regimen -3 tacrolimus through day +180; taper per institutional standards; may use cyclosporine if unable to tolerate tacrolimus Bone marrow infusion +1 IV methotrexate 15 mg/m2 +3 IV methotrexate 10 mg/m2 +6 IV methotrexate 10 mg/m2 +11

Endpoints Primary endpoint: estimate of overall survival at 2-years after biologic assignment with the goal of establishing that the difference in the proportion surviving is no more than 0.15 lower in the donor arm Analyze according to assigned treatment groups (ITT) Secondary endpoints: Sickle-related events, organ function (pulmonary, renal), 6 MWD test, HRQoL and pain assessments (via e-diary) Measured at baseline and 2-years at same institution Exception: HRQoL, pain and 6 MWD test measured at baseline, 1- and 2-years All participants will be monitored every 3 mos

Guidelines for Safety Monitoring Truncated SPRT for each rule Consult DSMB if cross upper boundary 100-day overall mortality: 15% vs 30% 1-year overall mortality Related donors: 15% vs 30% Unrelated donors: 15% vs 30% 100-day graft rejection Related donors: 10% vs 20%

Study Activation Benchmarks Protocol review committee – reviewed on 9/22/15 with second review of modified protocol on 12/15/15, approved 12/21/15. Data Safety Monitoring Board – reviewed on 1/19/16 Second DSMB review on March 23, 2016

Accrual Plan – BMT CTN 1503 Funding period: 5 years Accrue 200 patients over 3 years; Begin enrollment: 06/2016 End enrollment: 06/2019 Two-years follow-up from biologic assignment N = 27 centers have received contracts and 12 are fully executed; 13 of 15 awaiting final protocol/IRB approval to execute the contract N=13 additional sites indicate interest to participate Contact Lauren Zahra (lzahra@emmes.com)

Extended Follow up – BMT CTN 1503 Survival status on all participants will be followed annually through 10 years from biologic assignment Donor arm: followed through CIBMTR No donor arm: direct contact with hematologists at participating sites Those lost to follow up will be tracked annually searching the National Death Index Planned 10-year OS estimates/comparison incorporated into statistical plan Appropriate language in ICFs