ALLOGENEIC TRANSPLANT IN PATIENTS ≥60 YEARS OF AGE WITH FIRST RELAPSED OR REFRACTORY ACUTE MYELOID LEUKEMIA AFTER TREATMENT WITH VOSAROXIN OR PLACEBO PLUS CYTARABINE: RESULTS FROM VALOR

Background: Increasing numbers of older patients with acute myeloid leukemia (AML) receive allogeneic hematopoietic cell transplant (HCT) due to wider donor availability and improvements in supportive care that reduce transplant‐ related morbidity/mortality. HCT in patients >60 y/o with first relapsed or refractory (R/R) AML were examined from VALOR, a large phase 3 adaptive design, randomized, double‐blind, placebo‐controlled trial evaluating vosaroxin plus cytarabine (vos/cyt) vs placebo plus cytarabine (pla/cyt) [NCT01191801]. Aims: The aim of this posthoc subgroup analysis was to assess outcomes of HCT in patients >60 y/o with R/R AML. Methods: Patients were randomized 1:1 to receive cyt (1 g/m2 IV over 2 hr, d 1‐5) plus either vos (90 mg/m2 IV over 10 min, d 1 and 4; 70 mg/m2 in subsequent cycles) or placebo. We assessed complete remission (CR) rates prior to HCT, posttreatment HCT rates, HCT outcomes, and overall survival (OS) by treatment arm in R/R AML patients >60 y/o. Results: Overall, 451 patients >60 y/o received vos/cyt (n=226) or pla/cyt (n=225). Posttreatment HCTs were performed in 47 (20.8%) patients on vos/cyt and 44 (19.6%) patients on pla/cyt. Of the 91 HCT patients, 27 had achieved CR after vos/cyt vs 16 after pla/cyt. An additional 7 patients (vos/cyt) and 6 patients (pla/cyt) received subsequent therapy and went on to achieve CR, resulting in totals of 34 vos/cyt vs 22 pla/cyt patients who achieved CR prior to transplant. Median OS for patients who underwent posttreatment HCT on the vos/cyt arm was 20.2 mo vs 12.2 mo on the pla/cyt arm (HR 0.699; one sided P=0.088). There were no clinically meaningful differences between treatment arms with respect to transplantation type, complications associated with HCT (including graft‐vs‐host and veno‐occlusive disease), 100‐day mortality, or achievement of engraftment. Summary and Conclusions: While HCT rates were comparable between treatment arms in this older R/R AML population, higher pretransplant CR rates in the vos/cyt arm enabled more patients >60 y/o to undergo transplant while in CR as compared to the pla/cyt arm. With median OS lengthened by 8 months, a trend toward an OS benefit was observed for vos/cyt‐treated patients. Additional follow‐up is being conducted to further assess the impact of vos/cyt treatment on posttreatment HCT.