Application of the ASCO Value Framework and ESMO Magnitude of Clinical Benefit Scale to Assess the Value of Abiraterone and Enzalutamide in Advanced Prostate Cancer

Abstract

PURPOSE: As novel hormonal therapies, such as abiraterone and enzalutamide, move into earlier stages of treatment of advanced prostate cancer, there are significant cost implications. We used the ASCO Value Framework (AVF) and European Society of Medical Oncology (ESMO) Magnitude of Clinical Benefit Scale (MCBS) to quantify and compare the incremental clinical benefit and costs of these agents in the metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC) settings. METHODS: We searched PubMed for randomized phase III trials of abiraterone and enzalutamide in mCRPC and mCSPC. Incremental clinical benefit was quantified using the AVF and ESMO-MCBS by 2 independent assessors. Incremental drug costs were calculated using average wholesale prices (AWPs) from the RED BOOK Online. RESULTS: In mCRPC, 2 abiraterone trials (COU-AA-301 and COU-AA-302) and 2 enzalutamide trials (AFFIRM and PREVAIL) met search criteria. AVF scores ranged from 46.3 to 66.6, suggesting clinical benefit; ESMO-MCBS scores ranged from 3 to 5, with lower clinical benefit in the mCRPC predocetaxel setting. The overall incremental AWP ranged from $83,460.94 to $205,128.85. In mCSPC, 4 trials met criteria (LATITUDE, STAMPEDE, ENZAMET, and ARCHES; AVF scores were 79.8, 33.3, 59, and 17, respectively). All of the studies showed benefit except ARCHES. By ESMO-MCBS, both LATITUDE and STAMPEDE showed benefit (score for 4 for both studies); ENZAMET and ARCHES were not evaluable. The overall cost of treatment was significantly higher in the mCSPC setting. CONCLUSION: The AVF and ESMO-MCBS frameworks generated slightly different results but suggested that abiraterone and enzalutamide show clinical benefit in both mCRPC and mCSPC but trended to lower clinical benefit and increased costs in earlier disease stages. Further refinement of the AVF and ESMO-MCBS is needed to facilitate their use and their ability to inform clinical practice in a rapidly changing treatment landscape.