Safety and efficacy of 2-weekly cabazitaxel in metastatic castration-resistant prostate cancer

Objectives: To evaluate the safety and efficacy of a 2-weekly cabazitaxel schedule in patients with metastatic castration-resistant prostate cancer (mCRPC). Materials and methods: During the period October 2013 to February 2016, 43 patients with mCRPC were treated with cabazitaxel (16 mg/m², on days 1 and 15 of a 4-week cycle) together with prophylactic granulocyte colony-stimulating factor (G-CSF). The safety profile and efficacy (prostate-specific antigen [PSA] response; biological, clinical or radiological progression-free survival [PFS] and overall survival [OS]) of the treatment were analysed. Results: All patients had received prior docetaxel and 79.1% abiraterone acetate. At inclusion, 46.5% were aged >70 years and 27.9% had an Eastern Cooperative Oncology Group performance status ≥2. Six patients stopped treatment because of toxicity. Grade ≥3 toxicities were: asthenia (16.3%); neutropenia (11.6%); thrombocytopenia (9.3%); diarrhoea (7%), anaemia (4.7%), febrile neutropenia (4.7%) and haematuria (2.3%). In all, 52.4% achieved a ≥30% PSA response and 40.5% had a ≥50% PSA response. The median OS was 15.2 months. Conclusion: This prospective pilot study suggests that cabazitaxel 16 mg/m² given 2-weekly has a manageable toxicity profile in docetaxel- and abiraterone acetate-pretreated patients with mCRPC. A prospective phase III trial comparing this regimen with the standard cabazitaxel regimen is planned to confirm these results.