A single-center retrospective cohort analysis of venetoclax in post-transplant, relapsed/refractory multiple myeloma.

Abstract

e19514 Background: Despite recent advances, treatment of relapsed multiple myeloma (MM) remains a challenge. Pre-clinical studies suggest that bcl-2 inhibition can lead to MM cell death and may synergize with bortezomib. Methods: We performed a single-center, retrospective chart review of patients with relapsed MM following autologous stem cell transplantation (auto-HCT) who were treated with venetoclax, a bcl-2 inhibitor, with bortezomib. Results: 11 patients were identified. Median number of lines of prior therapy was 9 (range 5-13). 1 patient had documented high risk cytogenetics, defined as the presence of a 17p deletion, t(14;16), or t(14;20). In the 8 patients with cytogenetics/FISH available, no patients had t(11,14). 9/11 patients were refractory to bortezomib. 11/11 patients had progressed after carfilzomib, 9/11 after pomalidomide, and 11/11 after anti-CD38 antibody therapy. In all cases, patients were treated with venetoclax in combination with bortezomib. Patients were started at 400 mg daily for 7 days then increased to the median dose of 800mg daily. Overall patients received a median of 14.24 weeks of treatment (range 3-25.5). IMWG criteria were utilized to assess responses, including: 0/11 CR, 1/11 VGPR and 3/11 PR for an overall response rate of 36% (4/11). 1/11 had a minor response (light chain decrease by greater than 25% but less than 50%), 1/11 achieved stable disease, 5/11 had progressive disease. Median time to best response was 35 days (range 21-37) and median duration of response was 45 days (with several patients remaining on drug). All patients who responded had bortezomib-refractory disease. With median follow-up of 57 days, 4/11 patients have not progressed and 9/11 remain alive. The most common adverse effect was GI upset (bloating, nausea, vomiting, diarrhea) in 4/11 patients with no patients discontinuing due to side effects. There was no evidence of tumor lysis and there were no treatment-related deaths. Conclusions: Venetoclax is an active agent in relapsed multiple myeloma. Further efforts to study this therapy include prospective phase II trials and combination therapy with proteasome inhibitors and steroids.