The present study retrospectively evaluated the efficacy and safety of enzalutamide in different lines of metastatic castration-resistant prostate cancer (mCRPC) treatment in a real-world setting.

The clinical records of patients with mCRPC treated with enzalutamide between August 2015 and October 2017 were retrieved from all 7 public oncology centers in Hong Kong and reviewed. The primary endpoint was progression-free survival (PFS) in first (1L), second (2L), and third or fourth lines (3L or 4L) of CRPC treatment. Secondary endpoints included overall survival (OS), prostate-specific antigen (PSA) response, and tolerance.

Among a total of 117 patients (median age of 73 years [range, 52-90 years]), 34 (29.1%), 57 (48.7%), and 26 (19.3%) patients had enzalutamide as their 1L (chemo-naive), 2L (post-docetaxel or -abiraterone), and 3L or above treatment options. The overall PSA response rates were 43.6%, and were 73.5%, 35.1%, and 19.2% for 1L, 2L, and 3L or 4L treatment, respectively. PFS and OS were significantly associated with the line of treatment in the univariate survival analysis (1L/2L/3L and 4L; PFS, 7.1/3.9/2.2 months; OS, not reached/15.8/7.4 months; both P = .0002) but not in the multivariate analysis. The observed incidence of any fatigue (grade 1 or 2, 54.7%; grade 3 or 4, 9.4%) was much higher than reported in the AFFIRM (A Study Evaluating the Efficacy and Safety of the Investigational Drug MDV3100 [ClinicalTrials.gov Identifier: NCT00974311]) (any grade, 34%) and PREVAIL (A Multinational Phase 3, Randomized, Double-blind, Placebo-controlled Efficacy And Safety Study Of Oral Mdv3100 In Chemotherapy-naïve Patients With Progressive Metastatic Prostate Cancer Who Have Failed Androgen Deprivation Therapy [ClinicalTrials.gov Identifier: NCT00974311]) (any grade, 36%) trials; as well, grade ≥ 2 fatigue was significantly associated with 3L or 4L treatment (P = .01 in both univariate and multivariate analyses).

In the real-life setting, there was a higher incidence of enzalutamide-related fatigue than reported in the trials. Earlier lines of enzalutamide treatment were associated with longer PFS and OS, more frequent PSA response, and less fatigue.

Clinical genitourinary cancer. 2018 Jul 21 [Epub]

Darren M C Poon, Kenneth C W Wong, T W Chan, Kitty Law, Kuen Chan, Eric K C Lee, Conrad Lee, Michelle Chan, Hong Kong Society of Uro-Oncology (HKSUO)

Department of Clinical Oncology, State Key Laboratory in Oncology in South China, Sir YK Pao Centre for Cancer, Hong Kong Cancer Institute and Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong. Electronic address: ., Department of Clinical Oncology, State Key Laboratory in Oncology in South China, Sir YK Pao Centre for Cancer, Hong Kong Cancer Institute and Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Oncology, Princess Margaret Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Clinical Oncology, United Christian Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong., Department of Clinical Oncology, Queen Mary Hospital, Hong Kong; Hong Kong Society of Uro-Oncology (HKSUO), Hong Kong.

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