Isatuximab plus carfilzomib and dexamethasone in patients with early <i>versus</i> late relapsed multiple myeloma: IKEMA subgroup analysis

Abstract

Patients with multiple myeloma (MM) who experience early relapse within 12 months of therapy initiation are considered functional high-risk and represent an unmet need, needing better therapies to improve outcomes. The final IKEMA (NCT03275285) progression-free survival (PFS) analysis confirmed the significant PFS improvement reported at interim analysis with isatuximab (Isa) plus carfilzomib and dexamethasone (Kd; Isa-Kd) versus Kd in patients with relapsed MM (updated median PFS: 35.7 vs. 19.2 months; HR=0.58 [95.4% CI: 0.42–0.79]). This IKEMA subgroup analysis examined efficacy and safety of Isa-Kd versus Kd in patients who experienced early (n=61 [Isa-Kd], n=46 [Kd]) versus late relapse (n=104 [Isa-Kd], n=72 [Kd]). As expected, more aggressive features in baseline characteristics were observed in early relapse patients. Consistent with IKEMA overall population results, median PFS (early relapse: 24.7 vs. 17.2 months, HR=0.662 [95% CI: 0.407–1.077]); late relapse: 42.7 vs. 21.9 months, HR=0.542 [95% CI: 0.355–0.826]), minimal residual disease negativity (MRD–) (early relapse: 24.6% vs. 15.2%; late relapse: 37.5% vs. 16.7%), and MRD– complete response (≥CR) rates (early relapse: 18.0% vs. 10.9%; late relapse: 30.8% vs. 13.9%) were higher with Isa-Kd versus Kd, respectively, in both early and late relapse patients. Grade ≥3, serious treatment-emergent adverse events (TEAEs), and death rates were higher in late relapse Isa-Kd arm. However, the numbers of deaths were low and treatment exposure was significantly longer in Isa-Kd versus Kd late relapse patients. These results support the addition of Isa to Kd as standard-of-care therapy for relapsed and/or refractory MM regardless of relapse timing.