Severe neutropenia is a dose-limiting factor that occurs in up to 82% of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with cabazitaxel. This study evaluated the effectiveness of granulocyte colony-stimulating factor (G-CSF) plus ciprofloxacin as prophylaxis in post-docetaxel patients with mCRPC treated with cabazitaxel and at high risk for neutropenia.