Real-world treatment patterns and clinical outcomes among patients with relapsed/refractory multiple myeloma initiating their second, third, and fourth lines of treatment: data from the US Flatiron database

This study assessed real-world treatment patterns and clinical outcomes among patients with relapsed/refractory multiple myeloma (RRMM) who received second- (2 L), third- (3 L), and fourth-line (4 L) treatments. Among 3910 patients who received 2 L treatment, 42.6% and 20.4% went on to receive 3 L and 4 L treatment, respectively. Median age of patients who received 2 L treatment was 70 years. Before 2 L treatment, most patients had exposure to bortezomib (77.0%) and lenalidomide (70.0%). The most common 2 L regimens (±dexamethasone) were daratumumab + pomalidomide (7.7%), daratumumab + lenalidomide (7.6%), and daratumumab + bortezomib (6.0%); daratumumab + pomalidomide was most common in 3 L (11.3%) and 4 L (8.3%). Median progression-free survival was 13.8, 8.1, and 7.0 months and median overall survival was 61.3, 39.9, and 30.7 months in 2 L, 3 L, and 4 L, respectively. By multivariable Cox regression, worse-outcome predictors included higher International Staging System stage, frailty, high cytogenetic risk, and triple-class refractoriness. Overall, real-world treatment patterns for RRMM were heterogeneous, and new therapies are needed.