Objective To explored the feasibility and efficacy of a rapid ramp-up, 2-week maximum regimen of venetoclax (VEN) plus low-dose cytarabine (LDAC) for treating relapsed/refractory acute myeloid leukemia (R/R AML).

Methods We retrospectively analyzed patients with venetoclax-naïve R/R AML treated with VEN+LDAC between October 2018 and November 2023. On the first day, patients received 200 mg of VEN, and the dose was quickly increased to 400 mg for the rest of the treatment; cytarabine was administered subcutaneously at a low dose of 20 mg/m²/day. The treatment duration was 10 or 14 days, depending on the condition of bone marrow hyperplasia determined on the 8th day of treatment. No patients received venetoclax monotherapy. All patients responding to salvage therapy received VEN+LDAC until disease progression or transplantation.

Results Among the patients, the median follow-up duration was 27.5 months. No clinical manifestations of tumor lysis syndrome (TLS) occurred during the treatment. The overall response rate (ORR) was 68.75%, including four complete responses (CR), one complete remission with incomplete hematologic recovery (CRi), and six partial responses (PR). The median number of best treatment result cycles was one cycle. The median overall survival (OS) in the whole cohort was 5.8 (0.5-47.2) months; the median progression-free survival (PFS) was 22.2 (7.3-42.9) months. The major adverse events were grade 3-4 hematologic adverse events and infections.

Conclusions The 8th-day myelosuppression-adjusted VEN+LDAC regimen is a feasible salvage option with a reasonable safety profile in patients with venetoclax-naïve R/R AML. Most patients tolerated the 14-day treatment; the response was generally rapid in the responding patients.