criteria; immunomodulatory drugs; multiple myeloma; proteasome inhibitors; real-world analysis; real-world data; relapsed and refractory

We confirmed the benefit of addition of ixazomib to lenalidomide and dexamethasone in patients with relapsed and refractory multiple myeloma (RRMM) in unselected real-world population. We report the final analysis for overall survival (OS), second progression free survival (PFS-2), and the subanalysis of the outcomes in lenalidomide (LEN) pretreated and LEN refractory patients. Methods: We assessed 344 patients with RRMM, treated with IRD (N = 127) or RD (N = 217). The data were acquired from the Czech Registry of Monoclonal Gammopathies (RMG). With prolonged follow-up (median 28.5 months), we determined the new primary endpoints OS, PFS and PFS-2. Secondary endpoints included the next therapeutic approach and the survival measures in LEN pretreated and LEN refractory patients. Results: The final overall response rate (ORR) was 73.0% in the IRD cohort and 66.8% in the RD cohort. The difference in patients reaching VGPR remained significant (38.1% vs. 26.3%, p = 0.028). Median PFS maintained significant improvement in the IRD cohort (17.5 vs. 12.5 months, p = 0.013) with better outcomes in patients with 1–3 prior relapses (22.3 vs. 12.7 months p = 0.003). In the whole cohort, median OS was for IRD vs. RD patients 40.9 vs. 27.1 months (p = 0.001), with further improvement within relapse 1-3 (51.7 vs. 27.8 months, p < 0.001).