Clinically significant events associated with metastatic castration-resistant prostate cancer (mCRPC) treatments.

Abstract

61 Background: We describe the association between clinically significant events (CSEs) and mCRPC treatments in US-insured patients using an administrative claims database. Methods: Adult men in a large administrative claims database from Jan 2008 to Mar 2019 with ≥1 claim for prostate cancer, codes for pharmacologic or surgical castration, and incident metastatic disease during the identification period were included in the study. Patients who had ≥6 months of continuous enrollment before and after the index date (first metastatic claim) were included. Patients were followed until death, end of study, or disenrollment. Claims-based algorithms were used to identify patients with mCRPC, lines of therapy (LOTs), and CSEs of interest. CSEs were assessed in the first LOT in which an mCRPC regimen was used. Time on treatment was used as a person-time denominator to assess rates of CSEs per 365 days (treatment year) to control for differing times on treatment regimens. Results: Overall, we identified 3690 patients with mCRPC, of which 3150 (85%) received ≥1 LOT, among whom 1680/3150 (53%) received a regimen indicated for mCRPC. Average follow-up time was 705 days. CSEs occurred in 664/1680 (40%) patients, an average of 1.15 CSE per treatment year (Table). Patients had an average of 2 CSEs. The most common CSEs were anemia (14%), fatigue (15%), and back pain (10%). CSE rates per treatment year were highest among patients who received a taxane (1.7 per treatment year), taxane + gonadotropin-releasing hormone (GnRH) modulator (1.6 per treatment year), and other chemotherapy (1.6 per treatment year). Conclusions: Among treatments for patients with mCRPC, chemotherapy-based regimens showed the highest CSE rates per treatment year. These data indicate the burden of treatment for patients and can inform treatment decisions. [Table: see text]