Lenalidomide is an important component of initial
therapy in newly diagnosed
multiple myeloma, either as maintenance
therapy post-autologous
stem cell transplantation (ASCT) or as first-line
therapy with
dexamethasone for patients' ineligible for ASCT (non-ASCT). This retrospective study investigated treatment patterns and outcomes for ASCT-eligible and -ineligible patients who relapsed after
lenalidomide as part of first-line
therapy, based on data from the Canadian Myeloma Research Group Database for patients treated between January 2007 and April 2019. Among 256 patients who progressed on
lenalidomide maintenance
therapy, 28.5% received further immunomodulatory derivative-based (IMiD-based)
therapy (
lenalidomide/
pomalidomide) without a
proteasome inhibitor (PI) (
bortezomib/
carfilzomib/
ixazomib), 26.2% received PI-based
therapy without an IMiD, 19.5% received both an IMiD plus PI, 13.5% received
daratumumab-based regimens, and 12.1% underwent salvage ASCT. Median progression-free survival (PFS) was longest for
daratumumab-based
therapy (22.7 months) and salvage ASCT (23.4 months) and ranged from 6.6 to 7.3 months for the other treatments (P < .0001). Median overall survival (OS) was also longest for
daratumumab and salvage ASCT. A total of 87 non-ASCT patients received subsequent
therapy, with 66.7% receiving
bortezomib-based
therapy and 13.8% receiving other PI-based
therapy. Median PFS was 15.4 and 24.8 months for
bortezomib-based and other PI-based
therapy, respectively (P = .404). During most of the study period,
daratumumab was not funded; in this setting, switching to a different therapeutic class following relapse on
lenalidomide produced the longest remissions for non-ASCT patients. Further prospective studies are warranted to determine optimum treatment following relapse on
lenalidomide, especially in the light of increased access to
daratumumab.