BACKGROUND: Cabazitaxel/prednisone has been shown to prolong survival versus mitoxantrone/prednisone in patients with metastatic castration-resistant prostate cancer (mCRPC) that has progressed during or after docetaxel. Subsequently, compassionate-use programmes (CUPs) and expanded-access programmes (EAPs) were established worldwide, allowing access to cabazitaxel before its commercial availability. Preliminary results of the European CUP/EAP, focusing on the elderly population (aged > or =70 years), are reported. PATIENTS AND METHODS: Enrolled patients with progressive mCRPC received cabazitaxel (25 mg/m2) plus 10mg oral prednisone/prednisolone every 3 weeks until disease progression, death, unacceptable toxicity or physician/patient decision. Safety was analysed by age group ( or =75 years). The influence of selected variables on grade > or =3 neutropenia and/or neutropenic complications was analysed in multivariate analysis. RESULTS: 746 men were enrolled ( or =75 years, n=145). Number of cabazitaxel cycles, dose reductions for any cause, dose delays possibly related to cabazitaxel adverse events, and tolerability were similar in the three age groups. Prophylactic granulocyte colony-stimulating factor (G-CSF) use was more common in men aged > or =0 years. In multivariate analysis, age > or =75 years, treatment cycle 1, and neutrophil count or =3 neutropenia and/or neutropenic complications. Prophylactic use of G-CSF at a given cycle significantly reduced this risk by 30% (odds ratio 0.70, p=0.04). CONCLUSION: The results suggest that cabazitaxel has a manageable safety profile in everyday clinical practice. Prophylactic use of G-CSF, especially at cycle 1 and in men aged > or =75 years, is important and improves tolerability in senior adults treated with cabazitaxel.