Subgroup analysis of ICARIA‐MM study in relapsed/refractory multiple myeloma patients with high‐risk cytogenetics

Treatment benefit in multiple myeloma (MM) patients with high‐risk cytogenetics remains suboptimal. The phase 3 ICARIA‐MM trial (NCT02990338) showed that isatuximab plus pomalidomide–dexamethasone prolongs median progression‐free survival (mPFS) in patients with relapsed/refractory MM (RRMM). This subgroup analysis of ICARIA‐MM compared the benefit of isatuximab in high‐risk [defined by the presence of del(17p), t(4;14) or t(14;16)] versus standard‐risk patients. The efficacy of isatuximab in patients with gain(1q21) abnormality was also assessed in a retrospective subgroup analysis. In ICARIA‐MM, 307 patients received isatuximab–pomalidomide–dexamethasone (n = 154) or pomalidomide–dexamethasone (n = 153). Isatuximab (10 mg/kg intravenously) was given weekly in the first 28‐day cycle, and every other week thereafter. Standard pomalidomide–dexamethasone doses were given. Isatuximab–pomalidomide–dexamethasone improved mPFS (7·5 vs 3·7 months; HR, 0·66; 95% CI, 0·33–1·28) and overall response rate (ORR, 50·0% vs 16·7%) in high‐risk patients. In patients with isolated gain(1q21), isatuximab addition improved mPFS (11·2 vs 4·6 months; HR, 0·50; 95% CI, 0·28–0·88) and ORR (53·6% vs 27·6%). More grade ≥3 adverse events occurred in high‐risk patients receiving isatuximab (95·7%) versus the control group (67·6%); however, isatuximab did not increase events leading to discontinuation or treatment‐related mortality. Isatuximab–pomalidomide–dexamethasone provides a consistent benefit over pomalidomide–dexamethasone treatment in RRMM patients regardless of cytogenetic risk.