A Retrospective Database Analysis of Treatment Pathways in US Medicare Patients with Multiple Myeloma Following Sequential Treatment with Lenalidomide and a Proteasome Inhibitor

Introduction: Although multiple myeloma (MM) is currently incurable, the survival rate has improved over the past decade. Despite advances in treatment, most patients will become refractory to treatment. Lenalidomide and proteasome inhibitors (PI) are frequently used in early MM treatment regimens; however, there is a need to further understand how follow-up treatments affect patient outcomes. The aim of this retrospective database analysis was to examine the demographics, clinical characteristics, treatment sequencing, and overall survival in US Medicare patients with MM who initiated any MM treatment after observed treatment with lenalidomide and a PI.

Methods: Claims data from the Centers for Medicare and Medicaid Services (CMS) were assessed during the study period of January 1, 2016, through December 31, 2018. Medicare patients who were diagnosed with MM and had any MM therapy at least 28 days following treatment with lenalidomide and PI were eligible. The index date (ID) was the date of the first observed claim for any MM therapy as a next line of therapy (LOT) following treatment with lenalidomide and a PI. Patients were required to have ≥6 months of continuous enrollment prior to ID (baseline period). Patient data were assessed until health plan disenrollment, death, or end of study period (whichever occurred first).

Results: This study identified a cohort of 6590 eligible Medicare patients with MM exposed to lenalidomide and a PI. The mean age (standard deviation) was 72 (8.0) years, and 53.0% of patients were male. The Southern United States showed the largest representation of patients in this population (37.0%). The top baseline comorbidities included osteoarthritis (83.0%), hypertension (76.9%), anemia (76.7%), and respiratory infections (75.7%). PIs used in the lenalidomide/PI combination in the baseline period included bortezomib (67%), carfilzomib (30%), and ixazomib (29%). A patient could have received one or more of these PIs.

Of the 6590 patients who received index therapy, 51% had triplet therapy, 35% had doublet therapy, 10% had monotherapy, 3% had quad therapy, and <1% had another combination.

Among the 78% patients with a post-index LOT, 37% had triplet therapy, 37% had doublet therapy, 22% had monotherapy, 4% had quad therapy, and <1% had another combination. The most common therapies during the follow-up were dexamethasone (88%), lenalidomide (73%), bortezomib (45%), pomalidomide (31%), and daratumumab (31%). Patients could have received one or more of these therapies in the follow-up period. Overall, 4,788 (73%) patients were retreated with lenalidomide and 5,613 (85%) patients were retreated with a PI during the follow-up period.

Between the ID and the end of study period, 24.4% of patients died. The median (range) time to death was 211 (1─890) days from ID.

Conclusions: This study showed there was wide variation in subsequent treatment strategies following lenalidomide/PI exposure. After exposure, patients were most often treated with triplet therapies, and there was frequent re-treatment with previously used agents and/or classes. These results highlight the need for novel treatments/classes of therapy and sequencing strategies that may improve outcomes in patients with MM.

Funding: GSK (Study 213462)