The XRP6258 Plus Prednisone Compared to Mitoxantrone Plus Prednisone in Hormone Refractory Metastatic Prostate Cancer [TROPIC; NCT00417079] trial showed that treatment with cabazitaxel (CbzP) produced statistically significant improvement in overall survival versus mitoxantrone plus prednisone in patients with metastatic, castration-resistant prostate cancer (mCRPC) previously treated with a docetaxel-containing regimen (HR, 0.70; p<0.0001). Sevil E. Bavbek, MD, Istanbul University Oncology Institute, Istanbul, Turkey, presented interim results from a cohort compassionate-use program (CUP) with CbzP plus prednisone for patients with mCRPC [EAP; NCT01254279; Bavbek SE et al. J Clin Oncol (suppl; asbtr e15112) 2012].

Results from the TROPIC trial supported the establishment of a CUP and an early access program (EAP). The aims of this Phase 3, single-arm, open-label trial are to provide access to CbzP prior to commercial availability to mCRPC patients who may benefit from it, and to further assess the agent's safety profile. Estimated enrollment is 1600 patients from 250 centers globally. Eligible patients received CbzP in combination with oral prednisone until disease progression, death, unacceptable toxicity, or physician/patient decision.

Baseline characteristics and safety data are available for the first 399 patients. The median age is 68 years (range, 43 to 89); 90.2% of patients had ECOG Performance Status scale 0 to 1. The median cumulative dose of prior docetaxel was 675 mg/m²; previous therapy with mitoxantrone plus prednisone was allowed.

The median time from the last dose of docetaxel to progression was 4 months; 53.3% of patients experienced disease progression either during or <3 months after docetaxel therapy; 61% had =2 metastatic sites, most commonly bone (93.2%) and regional lymph nodes (34.4%). At the time of analysis, a median of four cycles of CbzP had been administered; four patients received =10 cycles.

Median relative dose intensity was 99.2% (range, 80.1 to 104.9). Granulocyte colony-stimulating factor was administered to 34.3% of patients in Cycle 1 (6.3% therapeutic, 26.6% prophylactic). Overall, 71.4% of patients had adverse events (AEs). The most common grade 3 to 4 AEs were neutropenia (11.3%), febrile neutropenia (6.3%), anemia (2.8%), fatigue (2%), neutropenic sepsis (1.8%), vomiting (1.3%), and diarrhea (1%). Eight (2%) treatment-related deaths were reported.

The investigators concluded that CUP/EAP provides additional safety data for CbzP in a routine clinical practice patient population with heavily pretreated mCRPC. Treatment was tolerable, with a predictable and manageable toxicity profile consistent with data reported for TROPIC and product labeling.