SUO 2017: Contemporary Trends in Abiraterone and Enzalutamide Prescription by Provider Specialty

Washington, DC ( Dr. Pucheril and colleagues discussed trends in abiraterone and enzalutamide prescription by provider and analysis of Medicare Part D 2013-15. For more than 70 years, androgen deprivation therapy (ADT) with LHRH-agonists and anti-androgens, is established in the management of prostate cancer and is administered by urologists, medical oncologists, and radiation oncologists. However, newer agents for ADT, abiraterone acetate and enzalutamide, were approved by the FDA in 2011 and 2012, respectively, for the management of metastatic castrate resistant prostate cancer (mCRPC) after failing chemotherapy. The objective of this study was to evaluate the contemporary economic burden of abiraterone and enzalutamide and their utilization by provider specialty.

The authors utilized Medicare Part D data from 2013-2015, considering that the majority of men with mCRPC are >65 years of age. The specific outcome variables of interest included the aggregate reimbursement and total number of prescriptions for abiraterone and enzalutamide, by provider specialty. Descriptive statistics and trend analysis were performed. From 2013-2015, the total number of prescriptions rose from 52,457 to 81,058 for abiraterone and from 17,141 to 69,181 for enzalutamide.

Though medical oncologists prescribed more than 75% of abiraterone/enzalutamide prescriptions each year, the proportion of prescriptions written by urologists increased annually: the greatest increase in the percentage of prescriptions from urologists occurred from 2013-2014 for abiraterone (3.96%  8.62%) and from 2014-2015 for enzalutamide (5.42%  15.64%). Interestingly, prescription use by radiation oncologists were negligible throughout the study. Overall, this represents considerable cost, considering that by 2015, the aggregate reimbursement of Part D claims for enzalutamide and abiraterone was $790 million each. 

In summary, while medical oncologists account for the vast majority of abiraterone and enzalutamide prescriptions, the utilization by urologists is increasing. Furthermore, enzalutamide and abiraterone are among the costliest medications covered by Medicare. As indications for the use of these medications increase and now include castrate-sensitive patients, further study should be directed at determining optimal timing and indication for prescription.

Presented by: Daniel T. Pucheril, MD, MBA¹

Co-Authors: Ye Wang PhD², Dimitar Zlatev MD¹, Paul Nguyen MD³, Adam Kibel MD¹ and Steven Chang MD, MS⁴

Affiliation: ¹Division of Urology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; ²Center for Surgery and Public Health, Harvard Medical School, Boston, MA; ³Radiation Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA; ⁴Division of Urology, Brigham and Women's Hospital, Center for Surgery and Public Health, Harvard Medical School, Boston, MA

Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC