Elotuzumab in combination with pomalidomide, bortezomib, and dexamethasone in relapsed and refractory multiple myeloma.

Abstract: Elotuzumab is a monoclonal antibody targeting signaling lymphocyte activation molecule F7 on plasma and natural killer cells, which enhances the activity of lenalidomide, pomalidomide, and bortezomib in multiple myeloma (MM). The OPTIMISMM study showed improved outcomes with the combination of pomalidomide, bortezomib, and dexamethasone (PVd) in relapsed/refractory MM. Therefore, we studied adding elotuzumab to PVd (elo-PVd) in relapsed/refractory MM in a multicenter phase 2 trial. The primary objective was to determine the overall response rate (ORR). Patients with relapsed/refractory disease and ≥1 prior line of treatment (including lenalidomide and a proteasome inhibitor) were eligible. For each 28-day cycle, elotuzumab was weekly for the first 2 cycles and then every other week; pomalidomide on days 1 to 21; bortezomib on days 1, 8, and 15; and dexamethasone weekly. The trial enrolled 48 patients with a median 3 prior lines (range, 1-9). Prior therapies included pomalidomide (33%), daratumumab (25%), and isatuximab (4%). The ORR was 56.3%, and the median progression-free survival (PFS) was 10 months. In patients with 1 prior line of therapy, ORR was 73.7%; median PFS was 23.4 months. Common grade ≥3 adverse events were neutropenia (33%); infections, any (33%); lung infection (27%); hypophosphatemia (19%); and thrombocytopenia (15%). Elo-PVd is, to our knowledge, one of the first trials of a quadruplet regimen in relapsed/refractory MM incorporating a monoclonal antibody to show efficacy across diverse prior treatments, including triple-class exposed patients with prior anti-CD38 monoclonal antibody. This trial was registered at ClinicalTrials.gov as #NCT02718833.