Second- and third-line treatment strategies in multiple myeloma: a referral-center experience

The treatment landscape for relapsed multiple myeloma (MM) has increased. In this study, we aimed to characterize 2nd (n = 1439) and 3rd (n = 1104) line regimens and compare the results between subgroups based on the year of treatment initiation (2nd line: 2003-2008, 2009-2015, 2016-2021; 3rd line: 2004-2009, 2010-2015, and 2016-2021). In both the second- and third- lines, we observed increasing use of novel agents (from 78 to 95% and from 77 to 95%, respectively) and triplet regimens (from 15 to 69% and from 21 to 71%, respectively). The most frequently used regimens in the last studied periods included lenalidomide-dexamethasone (RD; 14%), carfilzomib-RD (12%), and daratumumab-RD (10%) for the second-line, and daratumumab-pomalidomide-dexamethasone (11%) and daratumumab-RD (10%) for the third-line. The median time to the next treatment from second-line therapy has improved from 10.4 months (95% CI: 8.4-12.4) to 16.6 months (95% CI: 13.3-20.3; p < 0.001). The median overall survival from the first relapse increased from 30.9 months (95% CI: 26.8-183.0) to 65.8 months (95% CI: 50.7-72.8; p < 0.001). Over the last two decades, more patients were treated with newer agents and triplets for relapsed MM. The landscape of regimens has become more diverse, and survival after the first relapse is continually improving.