Real-world evidence of efficacy and safety of pomalidomide and dexamethasone in relapsed/refractory multiple myeloma patients: Czech registry data

We assessed the outcomes of pomalidomide and dexamethasone treatment in relapsed/refractory multiple myeloma (RRMM) patients with ≥1 prior line of therapy. We analyzed the data of all RRMM patients treated with pomalidomide and dexamethasone at nine Czech centers between 2013 and 2018. The source of the data was the Registry of Monoclonal Gammopathies of the Czech Republic. Primary endpoints included response rates based on International Myeloma Working Group criteria and survival measures, including progression-free survival (PFS) and overall survival (OS). Secondary endpoints were toxicities and previous treatment patterns, including refractory to lenalidomide, and their impact on final outcomes. The overall response rate was 51.8% and the clinical benefit rate (including patients with minimal response) was 67.1%, with 0.6% of complete responses, 8.5% of very good partial responses, and 42.1% of partial responses (PR). Overall, 16.5% of patients had a minimal response, and 32.3% had stable disease /progression. Median PFS was 8.8 months and the median OS was 14.2 months. In patients who achieved ≥PR, the median PFS and OS were significantly longer compared to non-responders (median PFS (12.1 vs. 4.5 months, p≤0.001 respectively), median OS (22.1 vs. 7.7 months, p≤0.001, respectively). The most frequent adverse events (AEs) were neutropenia (29.9%) and anemia (18.9%), non-hematological AEs included infections (14.6%) and fatigue (7.3%). Our analysis confirmed the effectiveness of pomalidomide and dexamethasone in a real-world setting. This therapy achieved reasonable outcomes comparable to the data from clinical trials even though this was an unbiased cohort of patients.