Evaluation of Treatment Patterns and Costs in Patients with Prostate Cancer and Bone Metastases

There are a lack of guideline recommendations for patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing treatment progression and sequencing. Understanding treatment patterns and associated utilization and costs may help inform stakeholders and guide decision making.

To describe treatment patterns and health care costs in prostate cancer (PC) patients with bone metastases treated with agents approved by the FDA for mCRPC.

2 large integrated claims databases (MarketScan and PharMetrics) were used to identify males aged ≥ 18 years who were diagnosed and treated for PC (ICD-9-CM code 185.xx or 233.4) with bone metastases (ICD-9-CM code 198.5) from June 2013 to September 2014. Patients were required to be continuously enrolled for ≥ 6 months before and after initiation of treatment with abiraterone, cabazitaxel, docetaxel, enzalutamide, mitoxantrone, radium-223, sipuleucel-T, or other chemotherapy. Study endpoints included lines of therapy, health care resource utilization per patient per month (PPPM), PPPM costs, and mortality rate. Descriptive analysis was completed for the study sample, and survival function was calculated via Kaplan-Meier estimates.

There were 953 patients meeting all inclusion criteria in the MarketScan database and 565 patients in the PharMetrics database. The median follow-up time was 18 months (interquartile range [IQR] = 14-23) for MarketScan and 14 months (IQR = 11-18) for PharMetrics. Mean age (SD) was 71 (± 10.7) and 66 (± 9.3) years, respectively. Before mCRPC treatment initiation, patients received palliative radiation therapy and bone antiresorptive therapy. For MarketScan and PharMetrics, respectively, 14.0% and 18.2% of patients received radiation therapy, 36.1% and 40.0% received denosumab; 16.5% and 16.8% received zoledronic acid; and 0.2% and 0.8% received pamidronate. Across both databases, abiraterone was the most commonly received bone metastasis treatment agent across all lines of therapy, except fourth line. Radium-223, cabazitaxel, and mitoxantrone were the least utilized therapies. The median cost PPPM during the post-index period was $10,916 (IQR=$5,334-$13,457) in MarketScan and $10,292 (IQR = $7,245-$14,699) in PharMetrics. The cost PPPM during the 6-month pre-index period was $2,643 (IQR = $850-$4,357) in MarketScan and $2,742 (IQR = $1,484-$4,730) in PharMetrics.

Patients were treated mainly with abiraterone across most lines of care, with radium-223, cabazitaxel, and mitoxantrone as the least utilized therapies. Median costs PPPM increased by approximately $8,900 after initiation of FDA-approved agents for mCRPC, with the largest increase in cost stemming from oral medications.

Funding for this study was provided by Bayer HealthCare Pharmaceuticals. All authors were employees at Bayer HealthCare Pharmaceuticals at the time this study was conducted. This study was presented as a poster at the 2017 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium; February 16-18, 2017; Orlando, FL.