To evaluate the efficacy of enzalutamide (Enz) as fourth- or fifth-line treatment in men with metastasized castration-resistant prostate cancer (mCRPC), by analyzing a retrospective cohort of heavily pretreated patients.
We evaluated toxicity, overall survival (OS), progression-free survival (PFS) and time to prostate-specific antigen (PSA) progression data from 47 CRPC patients treated with fourth- or fifth-line Enz.
All patients were treated with docetaxel and abiraterone acetate and 42 patients (89%) with cabazitaxel. The median age of the patients was 69 years (IQR, 63-73.5), 79% had bone metastases, 55% had lymph node metastases, and 17% had visceral metastases. The median duration of Enz treatment was 12.0 weeks (IQR, 8.3-20.4), and 11 patients (23%) responded to Enz (maximum PSA decline ≥50%). In general, Enz was well tolerated, with the most frequently reported adverse events being fatigue and nausea. The median OS was 40.1 weeks (95% CI, 25.4-61.4), the median PFS was 12.1 weeks (95% CI, 9.9-14.0) and the median time to PSA progression was 15.7 weeks (95% CI, 14.0-28.7).
Analysis of this retrospective cohort suggests that Enz is well tolerated and that there is a 23% response rate in heavily pretreated CRPC patients, which is comparable with third-line treatment outcomes.
Oncology. 2016 Aug 20 [Epub ahead of print]
Sushil K Badrising, Vincent van der Noort, Paul Hamberg, Jules L L M Coenen, Maureen J Aarts, Inge M van Oort, Alfons J M van den Eertwegh, Maartje Los, H Pieter van den Berg, Hans Gelderblom, Suzan Vrijaldenhoven, Emile D Kerver, Theo van Voorthuizen, Igle J de Jong, John B Haanen, Andries M Bergman, Dutch Uro-Oncology Study Group (DUOS)
Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.