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Cheng HH, Gulati R, Azad A, Nadal R, Twardowski P, Vaishampayan UN, Agarwal N, Heath EI, Pal SK, Rehman HT, Leiter A, Batten JA, Montgomery RB, Galsky MD, Antonarakis ES, Chi KN, Yu EY. Activity of enzalutamide in men with metastatic castration-resistant prostate cancer is affected by prior treatment with abiraterone and/or docetaxel. Prostate Cancer Prostatic Dis 2015; 18:122-7. [PMID: 25600186 PMCID: PMC4430366 DOI: 10.1038/pcan.2014.53] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/03/2014] [Accepted: 11/20/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Enzalutamide and abiraterone are new androgen-axis disrupting treatments for metastatic castration resistant prostate cancer (mCRPC). We examined response and outcomes of enzalutamide-treated mCRPC patients in the real-world context of prior treatments of abiraterone and/or docetaxel. METHODS We conducted a seven-institution retrospective study of mCRPC patients treated with enzalutamide between January 2009 and February 2014. We compared baseline characteristics, PSA declines, PSA progression-free survival (PSA-PFS), duration on enzalutamide, and overall survival (OS) across subgroups defined by prior abiraterone and/or docetaxel. RESULTS Of 310 patients who received enzalutamide, 36 (12%) received neither prior abiraterone nor prior docetaxel, 79 (25%) received prior abiraterone, 30 (10%) received prior docetaxel, and 165 (53%) received both prior abiraterone and prior docetaxel. Within these groups, respectively, ≥30% PSA decline was achieved among 67%, 28%, 43%, and 24% of patients; PSA-PFS was 5.5 (95% CI 4.2–9.1), 4.0 (3.2–4.8), 4.1 (2.9–5.4), and 2.8 (2.5–3.2) months; median duration of enzalutamide was 9.1 (7.3-not reached), 4.7 (3.7–7.7), 5.4 (3.8–8.4), and 3.9 (3.0–4.6) months. Median OS was reached only for patients who received both prior abiraterone and docetaxel and was 12.2 months (95% CI 10.7–16.5). 12-month OS was 78% (59%–100%), 64% (45%–90%), 77% (61%–97%), and 51% (41%–62%). Of 70 patients who failed to achieve any PSA decline on prior abiraterone, 19 (27%) achieved ≥30% PSA decline with subsequent enzalutamide. CONCLUSIONS The activity of enzalutamide is blunted after abiraterone, after docetaxel, and still more after both, suggesting subsets of overlapping and distinct mechanisms of resistance.
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Affiliation(s)
- H H Cheng
- 1] University of Washington, Seattle, WA, USA [2] Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - R Gulati
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - A Azad
- British Columbia Cancer Agency, Vancouver, BC, Canada
| | - R Nadal
- Sidney Kimmel Cancer Center/Johns Hopkins University, Baltimore, MA, USA
| | | | - U N Vaishampayan
- Karmanos Cancer Institute/Wayne State University, Detroit, MI, USA
| | - N Agarwal
- Huntsman Cancer Institute/University of Utah, Salt Lake City, UT, USA
| | - E I Heath
- Karmanos Cancer Institute/Wayne State University, Detroit, MI, USA
| | - S K Pal
- City of Hope Cancer Center, Duarte, CA, USA
| | - H-T Rehman
- Sidney Kimmel Cancer Center/Johns Hopkins University, Baltimore, MA, USA
| | - A Leiter
- Tisch Cancer Institute/Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J A Batten
- Huntsman Cancer Institute/University of Utah, Salt Lake City, UT, USA
| | - R B Montgomery
- 1] University of Washington, Seattle, WA, USA [2] Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - M D Galsky
- Tisch Cancer Institute/Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - E S Antonarakis
- Sidney Kimmel Cancer Center/Johns Hopkins University, Baltimore, MA, USA
| | - K N Chi
- British Columbia Cancer Agency, Vancouver, BC, Canada
| | - E Y Yu
- 1] University of Washington, Seattle, WA, USA [2] Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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