OBJECTIVES: This retrospective study describes healthcare resource utilization (HRU) and cost of care, by line of therapy (LOT), in Medicare Fee-for-Service (FFS) beneficiaries diagnosed with mCRPC initiating systemic treatment.

METHODS: A retrospective cohort study was conducted using the 100% sample of Medicare FFS medical, pharmacy, and enrollment data. Male beneficiaries with mCRPC were included if: a) initiated systemic therapy between January 1, 2015 and September 30, 2019 (index date: treatment start date), b) aged 66+ at the index, and c) continuously enrolled in Medicare for 12 months pre-index with prior exposure to androgen deprivation therapy and ≥3 months post index. A claims-based algorithm was used to identify up to four LOT. Direct all-cause and prostate-cancer (PC) related (based on primary diagnosis) Medicare payments and patient out of pocket (OOP) costs were evaluated during each LOT and adjusted to 2020 USD per patient per month (PPPM).

RESULTS: Among the 17,760 study patients who initiated 1LOT, 41.8% progressed to 2LOT; 17.9% progressed to 3LOT; and 7.4% progressed to 4LOT. Mean age at index: 77.5 (SD: 7.2) years. Mean (SD) all-cause Medicare payments PPPM and patient OOP payments PPPM by LOT were: 1LOT: $11,011 ($9,579) and $835 ($839), 2LOT: $14,383 ($25,848) and $1,024 ($1,715), 3LOT: $14,923 ($19,058) and $1,152 ($1,855), and 4LOT: $15,863 ($19,276) and $1,276 ($2,084). Mean (SD) Medicare payments PPPM for medical costs increased for each line from 1LOT $5,281 ($10,074) to 4LOT $13,285 ($19,197), and pharmacy costs decreased from 2LOT $6,310 ($9,801) to 4LOT $2,578 ($4,506). Prostate cancer-related costs comprised 75.7% of all-cause costs during 1LOT, 68.8% during 2LOT, 58.2% during 3LOT, and 50.8% during 4LOT.

CONCLUSION: Among male beneficiaries with mCRPC, medical cost of care increased with each subsequent LOT, while pharmacy costs decreased after the second line of therapy.