Measurable residual disease response in acute myeloid leukemia treated with venetoclax and azacitidine.

Abstract

7018 Background: In the phase 3 VIALE-A trial, rates of composite complete remission (CRc; complete remission [CR] + CR with incomplete hematologic recovery [CRi]) and measurable residual disease response (MRD<10-3) were higher in patients (pts) treated with venetoclax (Ven) + azacitidine (Aza) compared to Aza alone (23.4%/7.6%, p<0.001). There is limited evidence of the clinical significance of MRD monitoring in pts receiving low-intensity chemotherapy. Herein, we explored the outcomes of pts treated with Ven+Aza who achieved both CRc and MRD<10-3 in the VIALE-A trial (NCT02993523). Methods: Enrolled pts were ≥18 years and unfit for intensive chemotherapy. Pts received Ven 400 mg orally; days 1–28 and Aza 75 mg/m2; days 1-7/28-day cycle. Bone marrow aspirate samples for multiparametric flow cytometry assessments by integrated leukemia-associated immunophenotypes and different than normal procedures were collected for central analysis (Covance Central Laboratory Services) at baseline, end of cycle 1, and every 3 cycles thereafter. Assessments were performed independent of disease responses. MRD response was defined as <1 residual blast /1000 leukocytes (<10-3). CRc, DoR, OS, and EFS were assessed. Disease assessments were per modified International Working Group response criteria for AML. Results: 211/286 (74%) pts treated with Ven+Aza with at least one valid post-baseline MRD assessment were considered MRD evaluable; 78/211 (37%) achieved MRD<10-3 and 133/211 (63%) had MRD≥10-3. Median age (MRD<10-3/ MRD≥10-3) was 76 (range: 49-89)/77 (58-91) yrs. Pts (MRD<10-3/ MRD≥10-3) received median of 14.5 (range: 1-28) /7.0 (1-30) cycles of Ven+Aza. At median follow-up of 22.0 (range: 20.1-23.0)/20.8 (19.8-22.3) months (mos), CRc + MRD<10-3/ MRD≥10-3 was achieved by 67 (86%)/ 97 (73%); 20/67 (30%) achieved CRc + MRD<10-3 by end of cycle 1. Median DoR, OS, and EFS were not reached in pts with CRc + MRD<10-3 response (Table). The 12-mo estimates for DoR, OS, and EFS for pts with CRc + MRD<10-3response were 81.2%, 94.0%, and 83.2%, respectively. Adverse events ≥grade 3 (MRD<10-3/ MRD≥10-3) were febrile neutropenia (50%/43%), neutropenia (50%/35%), and thrombocytopenia (44%/44%), similar to the overall population. Conclusions: Pts with best response of CRc who achieved MRD<10-3 response with Ven+Aza treatment had longer DoR, OS, and EFS than pts who were CRc and MRD positive. Clinical trial information: NCT02993523. [Table: see text]