title: CAST: A retrospective analysis of cabazitaxel and abiraterone acetate sequential treatment in patients with metastatic castrate-resistant prostate cancer previously treated with docetaxel.
abstract: Cabazitaxel and abiraterone have both received approval for treating metastatic castrate-resistant prostate cancer (mCRPC) patients after first-line docetaxel therapy. In the cabazitaxel and abiraterone sequential treatment (CAST) study, the clinical outcome of docetaxel-treated mCRPC patients treated sequentially with both cabazitaxel and abiraterone was studied. Data were collected retrospectively from mCRPC patients at 12 hospitals across the Netherlands who initiated cabazitaxel and/or abiraterone before December 2012. Primary outcome measure was overall survival (OS); secondary measures were progression-free survival (PFS), biochemical PFS, and best clinical and PSA response. Hospital admission data during treatment were collected, as well as toxicities resulting in treatment discontinuation or patient death. Sixty-three and 69 patients received Cab→Abi (cabazitaxel prior to abiraterone) and Abi→Cab before July 10th, 2013, respectively. Median OS was 19.1 months and 17.0 months in Cab→Abi and Abi→Cab treated patients, respectively (p = 0.369). Median PFS and biochemical PFS were significantly longer in Cab→Abi treated patients: 8.1 versus 6.5 (p = 0.050) and 9.5 versus 7.7 months (p = 0.024), respectively. Although partial responses to cabazitaxel occurred in both groups, Abi→Cab treated patients had a significantly decreased antitumor response from cabazitaxel than Cab→Abi treated patients (median PFS 5.0 versus 2.6 months, p < 0.001). Minor differences in toxicities were observed based on therapy sequence; generally, toxicity from cabazitaxel could be severe, while abiraterone toxicity was milder. This retrospective analysis indicates that primary progression on cabazitaxel or abiraterone did not preclude a response to the other agent in mCRPC patients. However, tumor response of both agents, particularly cabazitaxel, was lower when administered as higher-line therapy in the selected study population.
authors.affiliation: Department of Medical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Michel D
authors.initials: MD
authors.lastname: Wissing
authors.forename: Jules L L M
authors.initials: JL
authors.lastname: Coenen
authors.forename: Pieter
authors.initials: P
authors.lastname: van den Berg
authors.forename: Hans M
authors.initials: HM
authors.lastname: Westgeest
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: van den Eertwegh
authors.forename: Inge M
authors.initials: IM
authors.lastname: van Oort
authors.forename: Monique M
authors.initials: MM
authors.lastname: Bos
authors.forename: André M
authors.initials: AM
authors.lastname: Bergman
authors.forename: Paul
authors.initials: P
authors.lastname: Hamberg
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Ten Tije
authors.forename: Maartje
authors.initials: M
authors.lastname: Los
authors.forename: Martijn P J K
authors.initials: MP
authors.lastname: Lolkema
authors.forename: Ronald
authors.initials: R
authors.lastname: de Wit
authors.forename: Hans
authors.initials: H
authors.lastname: Gelderblom
mesh_terms: D000069501:Abiraterone Acetate; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000736:Androstenes / Q000008:administration & dosage / Q000009:adverse effects; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D018572:Disease-Free Survival; D000077143:Docetaxel; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D012189:Retrospective Studies; D043823:Taxoids / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000736:Androstenes; D043823:Taxoids; D000077143:Docetaxel; C552428:cabazitaxel; D000069501:Abiraterone Acetate
keywords: abiraterone; cabazitaxel; docetaxel; prostate cancer; sequential treatment