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Cost-benefit analysis of AR-V7 testing in patients (Pts) with metastatic castration resistant prostate cancer (mCRPC) eligible for abiraterone (Abi) or enzalutamide (Enza).
Background: The rising cost of oncology care in the US is an ongoing societal challenge, and identifying biomarkers that inform clinical decisions and reduce the use of ineffective therapies remains elusive. A splice variant of the androgen receptor, AR-V7, was found to confer resistance to Abi and Enza in men with mCRPC, but did not negatively affect responses to taxanes, suggesting that early use of chemotherapy may be a more effective option for AR-V7(+) pts. With the recent development of a CLIA-certified clinical assay for AR-V7 at Johns Hopkins, we hypothesized that AR-V7 testing in mCRPC pts may result in cost savings by avoiding futile treatment with Abi/Enza in men with AR-V7(+) disease. Methods: We calculated the cost savings of performing AR-V7 testing in mCRPC pts prior to starting Abi/Enza (and avoiding these drugs in AR-V7(+) men) versus treating all mCRPC pts with Abi/Enza (without use of the biomarker). We have set the cost of the AR-V7 assay at $1000. The cost of 3 months of Abi/Enza (the minimum time it would take to determine resistance, clinically) was approximated at $20,000. We estimated that 30,000 mCRPC pts per year are eligible for Abi/Enza in the US. Results: In our prior studies, about 30% of mCRPC pts previously treated with Abi/Enza had detectable AR-V7 in CTCs. Assuming an AR-V7 prevalence of 30%, about 9,000 AR-V7(+) mCRPC pts per year would receive ineffective treatment with Abi/Enza, at an estimated cost of $180 Million. The upfront cost of testing all mCRPC pts who are Abi/Enza-eligible for AR-V7 is $30 Million, resulting in a net cost savings of $150 Million. When performing a continuous cost-benefit analysis after assuming other prevalences of AR-V7 (ranging from 4% to 50%) and a range of costs for Abi/Enza ($2000 to $24,000 per 3 months), we determined that AR-V7 testing would result in a cost savings as long as the prevalence of AR-V7 is > 5% (if the cost of 3 months of Abi/Enza remains at $20,000). Conclusions: AR-V7 testing in mCRPC pts (at $1000/test) is cost-beneficial when considering the current price of Abi/Enza, and may reduce the ineffective use of Abi/Enza leading to a net cost savings to the healthcare system.
Abstracts by Mark Christopher Markowski:
Clinical utility of CLIA-grade AR-V7 testing in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC).Meeting: 2017 Genitourinary Cancers Symposium | Abstract No: 183
- Meeting: 2015 ASCO Annual Meeting | Abstract No: e16105