Real-world economic burden associated with disease progression from metastatic castration-sensitive to castration-resistant prostate cancer on treatment in the United States.

Background: The advent of next-generation imaging will likely reduce nonmetastatic prostate cancer (PC) prevalence and increase identification of metastatic prostate cancer cases, resulting in two predominant advanced stages in the metastatic setting. There is a need to characterize changes in health care resource utilization (HRU) and costs when metastatic castration-sensitive PC (mCSPC) progresses to metastatic castration-resistant PC (mCRPC) to identify value drivers from current and new treatments.

Objective: To describe treatment patterns, HRU, and total health care costs among patients with mCSPC, before and after progression to mCRPC.

Methods: Clinical data from the Flatiron Metastatic PC Core Registry (January 1, 2013, to December 1, 2021) and linked claims from Komodo Health (January 1, 2014, to December 1, 2021) were used to identify patients with progression from mCSPC to mCRPC (date of progression was the index date) and subsequently initiated first-line mCRPC therapy on/after January 1, 2017. Treatment patterns and all-cause/PC-related HRU and health care costs were described per-patient-per-month (PPPM), separately for no more than 12 months pre-index (mCSPC disease state) and post-index (mCRPC disease state). Costs (payer's perspective) included those for services/procedures from medical claims and costs from pharmacy claims. Continuous HRU and costs were compared between the mCSPC and mCRPC disease states using Wilcoxon signed rank tests.

Results: Among 296 patients with mCSPC progressing to mCRPC (median age 69.0 years, 60.5% White, 15.9% Black), use of systemic therapies with androgen deprivation therapy increased dramatically from 35.1% in the mCSPC disease state to 92.9% in the mCRPC disease state, and use of androgen deprivation therapy monotherapy decreased from 25.7% to 2.4%, respectively. Although 39.2% received none of these therapies in the mCSPC disease state, this proportion decreased to 4.7% after transition to mCRPC. The mean number of days with PC-related outpatient visits increased from 1.57 to 2.16 PPPM in the mCSPC and mCRPC disease states (P < 0.001). From the mCSPC to mCRPC disease states, mean all-cause total health care costs PPPM increased from $4,424 (medical costs: $2,846) to $9,717 (medical costs: $4,654), and mean PC-related total health care costs PPPM increased from $2,859 (medical costs: $1,626) to $8,012 (medical costs: $3,285; all P < 0.001).

Conclusions: In this real-world study of patients with disease progression from mCSPC to mCRPC in US clinical practice, nearly 2-in-3 patients did not receive treatment with additional systemic therapies before progression to castration resistance. Post-progression, mean PC-related total costs increased nearly 3-fold, with a more than 2-fold increase in PC-related medical costs. Use of additional systemic therapies may delay the time and cost associated with disease progression to castration resistance.