Abiraterone Acetate (AA) is approved for the treatment of mCRPC after failure of androgen deprivation therapy in whom chemotherapy is not yet clinically indicated and for treatment of mCRPC progressed during or after docetaxel-based chemotherapy regimen. The aim of this study is to evaluate the role of early PSA decline for detection of therapy success or failure in mCRPC patients treated with AA in post chemotherapy setting.
We retrospectively evaluated 87 patients with mCRPC treated with AA. Serum PSA levels were evaluated after 15, 90 days and then monthly. The PSA flare phenomenon was evaluated, according to a confirmation value at least 1 week apart. The primary endpoint was to demonstrate that an early PSA decline correlates with a longer progression free survival (PFS) and overall survival (OS). The secondary endpoind was to demonstrate a correlation between better outcome and demographic and clinical patient characteristics.
We have collected data of 87 patients between Sep 2011 and Sep 2014. Early PSA response (≥50% from baseline at 15 days) was found in 56% evaluated patients and confirmed in 29 patients after 90 days. The median PFS was 5.5 months (4.6-6.5) and the median OS was 17.1 months (8.8-25.2). In early responders patients (PSA RR ≥ 50% at 15 days), we found a significant statistical advantage in terms of PFS at 1 year, HR 0.28, 95%CI 0.12-0.65, p = 0.003, and OS, HR 0.21 95% CI 0.06-0.72, p = 0.01. The results in PFS at 1 years and OS reached statistical significance also in the evaluation at 90 days.
A significant proportion (78.6%) of patients achieved a rapid response in terms of PSA decline. Early PSA RR (≥50% at 15 days after start of AA) can provide clinically meaningful information and can be considered a surrogate of longer PFS and OS.
Frontiers in pharmacology. 2016 May 18*** epublish ***
Gaetano Facchini, Orazio Caffo, Cinzia Ortega, Carmine D'Aniello, Marilena Di Napoli, Sabrina C Cecere, Chiara Della Pepa, Anna Crispo, Francesca Maines, Fiorella Ruatta, Gelsomina Iovane, Salvatore Pisconti, Maurizio Montella, Massimiliano Berretta, Sandro Pignata, Carla Cavaliere
Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Department of Medical Oncology, Santa Chiara Hospital Trento, Italy., Medical Oncology Department, Institute for Cancer Research and Treatment Candiolo, Italy., Department of Onco-Ematology Medical Oncology, S.G. Moscati Hospital of Taranto Taranto, Italy., Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Unit of Epidemiology, Struttura Complessa di Statistica Medica, Biometria e Bioinformatica, Fondazione IRCCS Istituto Nazionale Tumori Naples, Italy., Department of Medical Oncology, Santa Chiara Hospital Trento, Italy., Medical Oncology Department, Institute for Cancer Research and Treatment Candiolo, Italy., Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Department of Onco-Ematology Medical Oncology, S.G. Moscati Hospital of Taranto Taranto, Italy., Unit of Epidemiology, Struttura Complessa di Statistica Medica, Biometria e Bioinformatica, Fondazione IRCCS Istituto Nazionale Tumori Naples, Italy., Department of Medical Oncology, National Cancer Institute Aviano, Italy., Division of Medical Oncology, Department of Uro-Gynaecological Oncology, Istituto Nazionale Tumori "Fondazione G. Pascale" - IRCCS Naples, Italy., Department of Onco-Ematology Medical Oncology, S.G. Moscati Hospital of Taranto Taranto, Italy.