Treatment (tx) patterns among men with metastatic castration resistant prostate cancer (mCRPC) in the United States (US).

52 Background: Novel hormonal therapies (NHTs) and docetaxel were initially approved for the tx of men with mCRPC. Over time, these agents moved earlier in the disease continuum and are now also used in metastatic castration sensitive prostate cancer (mCSPC). Little is known about first-line (1L) mCRPC tx patterns for men with prior taxane-based chemotherapy (CT) or NHT exposure. This study evaluated the impact of taxane CT or NHT use in mCSPC on recent 1L tx patterns among men with mCRPC in the US. Methods: Participating physicians collected information from medical charts for the next consecutive 4 adult men with mCRPC during January-August 2020. A subset of men had prior mCSPC tx information available. 1L mCRPC txs were described overall and stratified by previous tx with taxane CT or NHT during mCSPC. No statistical comparisons were performed. Results: 116 adult men with mCRPC and known mCSPC tx history were included. Mean age was 70 years; 15% had known family history of prostate cancer; 70% had bone metastases and 33% had visceral metastases at data collection. Overall, 10% (12/116) of men had been previously treated with taxane CT and 28% (32/116) were treated with NHT during mCSPC. 1L mCRPC tx was initiated on average 35 days after mCRPC diagnosis. NHT was the most common 1L mCRPC tx regardless of prior taxane CT or NHT use. Men pre-treated with taxane CT were more likely to initiate mCRPC tx with NHT than taxane naïve men. NHT pre-treated men were less likely to initiate 1L mCRPC tx with NHT and more likely to initiate tx with docetaxel than NHT naïve men. 53% of men with prior NHT tx were rechallenged with NHTs in 1L mCRPC. (Table). Conclusions: Findings from this US real-world study among men with mCRPC suggest physicians most commonly initiate 1L mCRPC life-prolonging tx with NHT regardless of prior taxane CT or NHT exposure. Additional studies with larger sample sizes are needed to confirm these findings and better understand optimal tx sequencing, especially as new tx options become available.[Table: see text]