Real-world utilization patterns and survival in men with metastatic prostate cancer treated with Radium-223 in the United States.

Background: The treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) has evolved since radium-223 (Ra-223) was approved in the United States (2013). We examined treatment patterns and real-world overall survival (rwOS) of men with mCRPC treated with Ra-223 in the modern treatment era.

Methods: A retrospective cohort of men treated with Ra-223 was derived using private insurance data from the Komodo Health dataset from January 1, 2017 to June 30, 2022. Cox-regression analyses examined associations between Ra-223 use and rwOS with adjustment for covariates.

Results: Of 1376 men, the median age was 68 years, 51% were White, and 89% had bone-only metastases. Overall, 17%, 35%, and 25% of men received Ra-223 as first-line, second-line, or third-line treatment for mCRPC, respectively. Thirty-six percent received Ra-223 as combination/layered therapy, mainly with enzalutamide, and 46% completed ≥5 cycles. Overall, median rwOS was 22.9 months. Median rwOS was longer in men who completed ≥5 Ra-223 cycles versus 1-4 cycles (30.3 versus 15.3 months) and combination/layered therapy versus monotherapy (26.6 versus 20.5 months). Combination/layered therapy and completion of ≥5 Ra-223 cycles were associated with 22% and 55% reductions in risk of death in adjusted analyses, respectively. Limitations include some clinical information not captured by claims databases.

Conclusions: Significant rwOS benefits were identified in men who received Ra-223 as an earlier line of therapy, received Ra-223 in combination with another therapy, and completed ≥5 Ra-223 cycles, underscoring the importance of Ra-223 in the current treatment landscape.