Venetoclax and donor lymphocyte infusion for early relapsed acute myeloid leukemia after allogeneic hematopoietic cell transplantation. A retrospective multicenter trial.

Prognosis in patients with post allogeneic HCT-early relapse of acute myeloid leukemia (<6 months post HCT) is dismal and response to salvage treatment is < 20%. In addition, majority of patients at this early point are unable to withstand intensive salvage chemotherapy. We hypothesized that the combination of donor lymphocyte infusion (DLI) and venetoclax may result in increased response in this difficult to treat patient group. We retrospectively analyzed 22 patients from February 2017-December 2019, who were given the Venetoclax/DLI combination. Median age was 65 (43-75) years. There were no cases of tumor lysis syndrome. Microbiology documented infections occurred in 8 patients (36%). Majority were able to tolerate the protocol without admissions. Acute GVHD was observed in 4 (18%) patients and cGVHD was observed in 6 (27%) patients. Overall response was observed in 11 (50%) patients (CR, n = 4; CRi, n = 1; CRp, n = 4; MLFS n = 2). Median time to response was 28 (18-67) days and median cycles of venetoclax 2 [1-8] and duration of response were 135 (31-564) days. Median survival was 6.1 months (95% CI .73-11.4). Cox regression model for survival showed decreased WBC at relapse, GVHD and better performance status were associated with better survival. These results may endorse the hypothesis that enhancing alloreactivity combined with venetoclax is safe and efficacious and should be further investigated in prospective trials.