Background: Cbz + P demonstrated an overall survival benefit vs mitoxantrone + P in pts with mCRPC in the Phase III TROPIC trial. The CUP (CABAZ_C_05005) and EAP (NCT01254279) (both funded by Sanofi) were established to allow access to Cbz ahead of commercial availability. The programs are also evaluating Cbz safety in a real-world population. Data analyzed by age group (≤75 and >75 years) are presented here. Methods: Expected enrolment across both programs is 1,450 pts from 236 centres worldwide. Pts received Cbz 25 mg/m² IV Q3W + P 10 mg QD until disease progression, death, unacceptable toxicity or physician/pt decision. G-CSF is administered as per ASCO guidelines. Results: As of May 30, 2012, 1,301 pts have enrolled (≤75 years: 1,061 pts [81.6%]; >75 years: 240 pts [18.4%]). Eastern Cooperative Oncology Group performance status and incidence of visceral metastases were generally balanced between treatment groups. The most frequent reasons for discontinuation were disease progression (46.8%) followed by adverse events (AEs; 24.4%) in pts ≤75 years, and AEs (36.4%) followed by disease progression (31.1%) in pts >75 years. Time from initial diagnosis to inclusion was greater in pts >75 years (median 79.66 months) than in pts ≤75 years (median 53.94 months), but time from mCRPC diagnosis to inclusion was approximately equivalent (>75 years: median 22.6 months; ≤75 years: median 20.94 months). G-CSF use was more frequent in pts >75 years (cycle 1: 62.9% of pts) compared with pts ≤75 years (cycle 1: 52.2% of pts). AEs of clinical concern were more frequent in the older age group (Grade ≥3 AEs: >75 years 64.2%; ≤75 years 54.8%). Grade ≥3 neutropenia was observed in 25.8% of pts >75 years and in 17.0% of pts ≤75 years. Conclusions: We observed several differences between age groups in baseline and on-treatment parameters, suggesting differences in the natural history of mCRPC (faster disease progression in pts ≤75 years than in pts >75 years) and secondary to treatment (AEs more frequent in pts >75 years compared with pts ≤75 years). Clinical trial information: NCT01254279.