Plasma androgen receptor (AR) gain identifies metastatic castration-resistant prostate cancer (mCRPC) patients with worse outcome on abiraterone/enzalutamide, but its relevance in the context of taxane chemotherapy is unknown. We aimed to evaluate whether docetaxel is active regardless of plasma AR and to perform an exploratory analysis to compare docetaxel with abiraterone/enzalutamide. This multi-institutional study was a pooled analysis of AR status, determined by droplet digital polymerase chain reaction, on pretreatment plasma samples. We evaluated associations between plasma AR and overall/progression-free survival (OS/PFS) and prostate-specific antigen (PSA) response rate in 163 docetaxel-treated patients. OS was significantly shorter in case of AR gain (hazard ratio [HR]=1.61, 95% confidence interval [CI]=1.08-2.39, p=0.018), but not PFS (HR=1.04, 95% CI 0.74-1.46, p=0.8) or PSA response (odds ratio=1.14, 95% CI=0.65-1.99, p=0.7). We investigated the interaction between plasma AR and treatment type after incorporating updated data from our prior study of 73 chemotherapy-naïve, abiraterone/enzalutamide-treated patients, with data from 115 first-line docetaxel patients. In an exploratory analysis of mCRPC patients receiving first-line therapies, a significant interaction was observed between plasma AR and docetaxel versus abiraterone/enzalutamide for OS (HR=0.16, 95% CI=0.06-0.46, p<0.001) and PFS (HR=0.31, 95% CI=0.12-0.80, p=0.02). Specifically, we reported a significant difference for OS favoring abiraterone/enzalutamide for AR-normal patients (HR=1.93, 95% CI=1.19-3.12, p=0.008) and a suggestion favoring docetaxel for AR-gained patients (HR=0.53, 95% CI=0.24-1.16, p=0.11). These data suggest that AR-normal patients should receive abiraterone/enzalutamide and AR-gained could benefit from docetaxel. This treatment selection merits prospective evaluation in a randomized trial. PATIENT SUMMARY: We investigated whether plasma androgen receptor (AR) predicted outcome in metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel, and we performed an exploratory analysis in patients treated with docetaxel or AR-directed drugs as first-line mCRPC therapy. We showed that plasma AR normal favored hormonal treatment, whilst plasma AR-gained patients may have had a longer response to docetaxel, suggesting that plasma AR status could be a useful treatment selection biomarker.
European urology. 2018 Oct 26 [Epub]
Vincenza Conteduca, Anuradha Jayaram, Nuria Romero-Laorden, Daniel Wetterskog, Samanta Salvi, Giorgia Gurioli, Emanuela Scarpi, Elena Castro, Mercedes Marin-Aguilera, Cristian Lolli, Giuseppe Schepisi, Antonio Maugeri, Anna Wingate, Alberto Farolfi, Valentina Casadio, Ana Medina, Javier Puente, Mª José Méndez Vidal, Rafael Morales-Barrera, Jose C Villa-Guzmán, Susana Hernando, Alejo Rodriguez-Vida, Aránzazu González-Del-Alba, Begoña Mellado, Enrique Gonzalez-Billalabeitia, David Olmos, Gerhardt Attard, Ugo De Giorgi
Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy; Centre for Evolution and Cancer, The Institute of Cancer Research, London, UK. Electronic address: ., Centre for Evolution and Cancer, The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK; University College London Cancer Institute, London, UK., Prostate Cancer Clinical Research Unit, Spanish National Cancer Research Centre, Madrid, Spain; Hospital Universitario La Princesa, Madrid, Spain., Centre for Evolution and Cancer, The Institute of Cancer Research, London, UK; University College London Cancer Institute, London, UK., Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy., Prostate Cancer Clinical Research Unit, Spanish National Cancer Research Centre, Madrid, Spain; Hospital Universitario Quirón, Madrid, Spain., Department of Medical Oncology, IDIBAPS, Hospital Clínico y Provincial, Barcelona, Spain., Centro Oncológico de Galicia, A Coruña, Spain., Medical Oncology Department, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), CIBERONC, Madrid, Spain., Hospital Reina Sofía, Córdoba, Spain., Vall d'Hebron Institute of Oncology, Vall d' Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain., Hospital General Universitario de Ciudad Real, Ciudad Real, Spain., Fundación Hospital Alcorcón, Alcorcón, Spain., Hospital del Mar, Barcelona, Spain., Hospital Universitario Son Espases, Palma de Mallorca, Spain., Department of Hematology & Medical Oncology, Hospital Universitario Morales Meseguer, IMIB-Universidad de Murcia, Murcia, Spain; Universidad Católica San Antonio de Murcia-UCAM, Murcia, Spain., Prostate Cancer Clinical Research Unit, Spanish National Cancer Research Centre, Madrid, Spain; CNIO-IBIMA Genitourinary Cancer Research Unit, Hospitales Universitario, virgen de la Victoria y regional de Málaga, Spain., Centre for Evolution and Cancer, The Institute of Cancer Research, London, UK; The Royal Marsden NHS Foundation Trust, London, UK; University College London Cancer Institute, London, UK. Electronic address: .