Erschienen in:
01.10.2014 | Original Article
Is there an anti-androgen withdrawal syndrome for enzalutamide?
verfasst von:
Christoph A. J. von Klot, Mario W. Kramer, Alena Böker, Thomas R. W. Herrmann, Inga Peters, Markus A. Kuczyk, Uwe Ligges, Jürgen E. Gschwend, Margitta Retz, Sebastian C. Schmid, Arnulf Stenzl, Christian Schwentner, Tilmann Todenhöfer, Michael Stöckle, Carsten-Henning Ohlmann, Ines Azone, René Mager, Georg Bartsch, Axel Haferkamp, Axel Heidenreich, Charlotte Piper, Axel S. Merseburger
Erschienen in:
World Journal of Urology
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Ausgabe 5/2014
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Abstract
Background
The anti-androgen withdrawal syndrome (AAWS) can be seen in one-third of patients after discontinuation of first-generation non-steroidal anti-androgen therapy. With the introduction of new agents for anti-androgen therapy as well as alternate mechanisms of action, new therapeutic options before and after docetaxel chemotherapy have arisen (Ohlmann et al. in World J Urol 30(4):495–503,
2012). The question regarding the occurrence of an enzalutamide withdrawal syndrome (EWS) has not been evaluated yet. In this study, we assess prostate-specific antigen (PSA) response after discontinuation of enzalutamide.
Methods
In total 31 patients with metastatic castration-resistant prostate cancer (mCRPC) underwent an enzalutamide withdrawal and were evaluated. Data were gathered from 6 centres in Germany. Patients with continuous oral administration of enzalutamide with rising serum PSA levels were evaluated, starting from enzalutamide withdrawal until subsequent therapy was initiated, follow-up ended or death of the patient occurred. Statistical evaluation was performed applying one-sided binomial testing using R-statistical software, version 3.0.1.
Results
Mean withdrawal follow-up was 6.5 weeks (range 1–26.1 weeks). None of the 31 patients showed a PSA decline. Mean relative PSA rise over all patients was 73.9 % (range 0.5–440.7 %) with a median of 44.9 %.
Conclusions
If existent, an AAWS is at least very rare for enzalutamide in patients with mCRPC after taxane-based chemotherapy and does not play a clinical role in this setting. This may be attributed to the different pharmacodynamics of enzalutamide. Longer duration of therapy or a longer withdrawal interval may reveal a rare EWS in the future.