Pomalidomide plus low-dose dexamethasone in multiple myeloma with deletion 17p and/or translocation (4;14): IFM 2010-02 trial results

Abstract

The combination of pomalidomide and low-dose dexamethasone (Pom-Dex) can be safely administered to patients with end-stage relapsed/refractory multiple myeloma (RRMM). However, we observed a shorter median progression-free survival (PFS) and overall survival (OS) in these patients when characterized with adverse cytogenetics (deletion 17p and translocation [4;14]) in the Intergroupe Francophone Myélome (IFM) 2009-02 trial. We then sought to determine whether MM with adverse cytogenetics would benefit more from Pom-Dex if exposed earlier in the multicenter IFM 2010-02 trial. The intention-to-treat population included 50 patients, with a median age of 63 years (38% were ≥65 years). Interestingly, there was a striking difference in time to progression (TTP), duration of response, and overall response rate (ORR) according to the presence of del(17p) compared with t(4;14) (TTP, 7.3 vs 2.8 months; duration of response, 8.3 vs 2.4 months; and ORR, 32% vs 15%). OS was prolonged after Pom-Dex, particularly in t(4;14), given the short TTP, suggesting that patients were rescued at relapse with further lines of therapy. Pom-Dex, a doublet immunomodulatory drug-based regimen, is active and well tolerated in adverse cytogenetic patients with early RRMM, particularly in those with del(17p), who are characterized by a high and rapid development of a refractoriness state and known for their poor prognosis. Future studies will determine the underlying mechanisms of Pom-Dex activity in del(17p).