Isatuximab plus pomalidomide and dexamethasone (Isa-Pd) significantly prolongs progression-free survival (PFS) and improves overall response rate (ORR) compared with pomalidomide plus dexamethasone alone (Pd) in patients with relapsed or refractory multiple myeloma, according to a subgroup analysis of the phase III ICARIA-MM study.
These trends remain consistent among patients with soft-tissue plasmacytomas, researchers also found.
The ICARIA-MM trial demonstrated benefit with Isa-Pd compared with Pd alone in relapsed or refractory multiple myeloma. However, patients with soft-tissue plasmacytomas have a poor prognosis and newer therapies are needed.
The ICARIA-MM overall population included 154 patients treated with Isa-Pd (isatuximab administered intravenously 10 mg/kg weekly for 4 weeks, and every other week thereafter) and 153 patients treated with Pd. If soft-tissue plasmacytomas were present at study entry, researcher carried out a CT scan or an MRI at baseline and repeated every 12 weeks or when clinically indicated. Imaging results were analyzed by an independent review committee.
The primary objective of the analysis was to assess the impact of Isa-Pd on PFS compared with Pd. Safety information included treatment-emergent adverse events – assessed according to National Cancer Institute Common Toxicity Criteria for Adverse Events version 4.03.
Results of the analysis were presented by Meral Beksac, MD, department of hematology, Ankara University (Turkey), and colleagues at the European Hematology Association (EHA) Annual Meeting (June 11-21, 2020).
Researchers noted that at study entry, 7.8% (n = 24; 14 in the Isa-Pd arm, 10 in the Pd arm) of patients presented with soft-tissue plasmacytomas. PFS was improved in the Isa-Pd arm (HR, 0.22; 95% CI, 0.07-0.69); median PFS was 4.57 vs 1.56 months, respectively. The probability of PFS at 12 months was 0.31 vs 0.00, respectively.
Additionally, researchers found that ORR was improved in the Isa-Pd arm vs the Pd arm (50% vs 10%, respectively).
Grade 3 or higher treatment-emergent adverse events occurred in 85.7% and 70% of patients, respectively. While infusion reactions of any grade occurred in 42.9% of patients in the Isa-Pd arm, there were no reported grade 3 or higher infusion reactions.
“In patients with relapsed or refractory multiple myeloma and plasmacytomas, Isa-Pd treatment significantly prolonged PFS and improved ORR compared with Pd alone, with a manageable safety profile,” authors of the study concluded. “The trend in efficacy and safety of plasmacytoma patients treated with Isa-Pd are consistent with the ICARIA-MM overall population and other study subgroups.”—Zachary Bessette
