ASCO GU 2018: Indirect Treatment Comparison of Abiraterone Acetate Plus Prednisone and Docetaxel on Patient-reported Outcomes in Metastatic Castration-naïve Prostate Cancer (mCNPC)

San Francisco, CA (UroToday.com) Dr. Feyerabend presented results of their group’s indirect treatment comparison of abiraterone acetate plus prednisone and docetaxel on patient reported outcomes among men with mCNPC at today’s GU ASCO 2018 prostate cancer poster session. As was reported last year at ASCO 2017, abiraterone acetate plus prednisone added to androgen deprivation therapy (ADT) improved overall survival (OS) among newly diagnosed mCNPC patients with high-risk disease vs placebos + ADT in the phase III LATITUDE study. Although ADT with or without chemotherapy is recommended in clinical guidelines as the mainstay of management for mCNPC, adding docetaxel to ADT may not improve health-related quality of life (HRQoL). The objective of this study was to perform an indirect treatment comparison to understand the relative impact of abiraterone acetate plus prednisone vs docetaxel on patient reported outcomes for men with mCNPC.

For this study, the authors assessed patient reported outcomes using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) and Brief Pain Inventory (BPI). The mean change from baseline was based on differences in FACT-P and BPI scores between active vs control arms in LATITUDE [1] (intention-to-treat ITT population) and CHAARTED [2] (available data included mCNPC pts with high-volume disease and low-volume disease). Higher FACT-P score indicates better outcome/function and lower BPI score indicates better outcome/less pain. The probability of abiraterone acetate plus prednisone being superior to docetaxel at 3, 6, 9, and 12 months after treatment was based on fixed-effects Bayesian network meta-analysis. The benefit in patient reported outcomes with abiraterone acetate plus prednisone vs docetaxel were seen at 3 months and sustained for at least 1 year after treatment. This was consistent at each time point and for both FACT-P and BPI tools. The Bayesian probability of abiraterone acetate plus prednisone being the better treatment for patient reported outcomes ranged from 92.3% to 100%, with higher probabilities noted earlier in follow-up.

The authors summarized that results from a Bayesian indirect treatment comparison suggest that abiraterone acetate plus prednisone was superior to docetaxel in improving patient reported outcomes for at least one year after initiating treatment in men with mCNPC. Additionally, network meta-analysis studies comparing these two agents also suggest that abiraterone acetate plus prednisone has an 89% probability of being the preferred treatment when indirectly evaluating OS [3]. In the absence of head-to-head trials, these analyses can provide useful insights on the relative impact of treatment options on HRQoL in mCNPC patients.

Speaker: Susan Feyerabend, Studienpraxis Urologie, Nürtingen, Germany

Co-Authors: Fred Saad, Tracy Li, Tetsuro Ito, Joris Diels, Suzy Van Sanden, Peter De Porre, Seye Abogunrin, Maria Koufopoulou, Karim Fizazi

Written by: Zachary Klaassen, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Twitter:@zklaassen_md at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA

References:
1. Fizazi K, Tran N, Fein L, et al. Abiraterone plus Prednisone in Metastatic, Castration-Sensitive Prostate Cancer. N Engl J Med. 2017;377(4):352-360.
2. James ND, de Bono JS, Spears MR, et al. Abiraterone for Prostate Cancer Not Previously Treated with Hormone Therapy. N Engl J Med. 2017;377(4):338-351.
3. Wallis CJD, Klaassen Z, Bhindi B, et al. Comparison of abiraterone acetate and docetaxel with androgen deprivation therapy in high-risk and metastatic hormone-naïve prostate cancer: A systematic review and network meta-analysis. Eur Urol 2017 [Epub ahead of print].
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