Cost-Savings Analysis of AR-V7 Testing in Patients With Metastatic Castration-Resistant Prostate Cancer Eligible for Treatment With Abiraterone or Enzalutamide.

INTRODUCTION: Identification of cancer biomarkers that inform clinical decisions and reduce the use of ineffective therapies is a major goal of precision oncology. An abnormal splice variant of the androgen receptor, AR-V7, was recently found to confer resistance to novel hormonal therapies (abiraterone and enzalutamide) in men with metastatic castration-resistant prostate cancer (mCRPC), but did not negatively affect responses to taxane chemotherapies, suggesting that early use of chemotherapy may be a more effective option for AR-V7(+) patients.

METHODS: We calculated the cost savings of performing AR-V7 testing in mCRPC patients prior to starting abiraterone/enzalutamide (and avoiding these drugs in AR-V7(+) men) versus treating all mCRPC patients empirically with abiraterone/enzalutamide (without use of the biomarker).

RESULTS: We determined that AR-V7 testing would result in substantial cost savings as long as the true prevalence of AR-V7 was >5%. In our prior studies, we estimated that approximately 30% of mCRPC patients may have detectable AR-V7 in circulating tumor cells (CTCs). In this population, upfront testing of AR-V7 status (at a price of $1,000 per test) would result in a net cost savings of $150 Million in the United States per year.

CONCLUSIONS: AR-V7 testing in mCRPC patients would be cost-beneficial when considering the current price of treatment, and may reduce the ineffective use of abiraterone/enzalutamide, leading to a significant net cost savings to the healthcare system. Clinical-grade AR-V7 testing is currently available at our institution. Prostate 76:1484-1490, 2016. © 2016 Wiley Periodicals, Inc.