Background: Significant advances in multiple myeloma treatments have been made in recent years, but real-world data on outcomes with these newer agents in patients with relapsed/refractory disease are limited. We report treatment patterns and survival outcomes from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database for patients with multiple myeloma who have received 1–3 prior lines of therapy (LOT), including a proteasome inhibitor (PI) and immunomodulatory drug (IMiD), and are lenalidomide-refractory.
Methods: Data collected from January 2016 to December 2019 (last available data) were assessed. Adult multiple myeloma patients were included if they had received 1–3 prior LOT, were exposed to a PI and IMiD, and were lenalidomide-refractory. Time zero (T0) was defined as the start date of the first treatment post eligibility. Descriptive statistics were used to evaluate patient characteristics at baseline and treatment patterns, stratified by prior LOT. The Kaplan-Meier method was used to analyze survival outcomes, including overall survival and time to next treatment. Overall survival was defined as the time interval between T0 and all-cause mortality. Time to next treatment was defined as the time interval between T0 and start of subsequent treatment or death, whichever occurred first.
Results: From 70,262 multiple myeloma patients, 1,319 were identified (1 prior LOT: n=466; 2 prior LOT: n=641; 3 prior LOT: n=212), with a median time from multiple myeloma diagnosis to T0 of 25.1 months. The median age of patients was 75 years, 52.5% were male, 82.6% were White, and 10.9% were Black. The mean Charlson comorbidity index was 3. Overall, approximately 85 unique subsequent treatment regimens were identified. The most common regimens based on hierarchy were daratumumab- (24.2%), pomalidomide- (16.5%), and carfilzomib-based (13.0%). Doublet therapies were the most common regimen for patients with 1 prior LOT (36.7%) and 2 prior LOT (38.2%), whereas triplet therapies were the most common for those with 3 prior LOT (35.4%). Overall, the most common regimens were pomalidomide/dexamethasone (7.6%), daratumumab/pomalidomide/dexamethasone (6.5%), daratumumab/bortezomib/dexamethasone (6.4%), and bortezomib/pomalidomide/dexamethasone (5.6%). Median overall survival was 32.1 months for patients with 1 prior LOT, 17.7 months for patients with 2 prior LOT, and 10.8 months for patients with 3 prior LOT; median time to next treatment (serving as a proxy for progression-free survival) was 5.5, 5.7, and 4.5 months, respectively.
Conclusion: Patients with 1–3 prior LOT who are PI- and IMiD-exposed, and lenalidomide-refractory progress quickly through currently available treatments, and survival outcomes remain poor. This population-based analysis shows the absence of a clear standard of care for this difficult-to-treat, older, comorbid patient population, and highlights the need for new and effective treatment regimens, as well as multidisciplinary supportive care.