An Audit of the Use of Cabazitaxel for the Treatment of Metastatic Castrate Resistant Prostate Cancer (mCRPC) Compared with Previous Experience with ECarboF (Epirubicin, Carboplatin and 5-fluorouracil) in a Single Institution

Purpose: Cabazitaxel (CBZ) improves overall survival in patients withmCRPC previously treated with docetaxel chemotherapy. Prior to cancer drugs fund access of CBZ, patients at University College London Hospital were treated with ECarboF. We report our experiences of CBZ compared with ECarboF. Methods: A retrospective analysis comparing CBZ (10/2013-2/2015) and ECarboF (3/2007-10/2010) was performed. Patients were identified through an electronic prescribing system. Patients’ records were used to identify demographics, treatment responses and toxicities. Survival was estimated using the methods of KaplaneMeier and compared by Cox proportional hazards. Biochemical response rates (BRR; end of treatment PSA > 30% reduction from baseline) and toxicity were compared by chi-squared tests. Results: 23 and 35 patients were identified in the CBZ and ECarboF groups, respectively. CBZ patients were more heavily pre-treated than ECarboF patients (96% versus 0% received second generation hormone therapy). Treatment was generally well tolerated although therewas 1 neutropenic death in each group. Grade 3/4 haematological toxicity was comparable in both groups and grade 3/4 non-haematological toxicities were more frequent in those treated with CBZ. The BRR was similar in the CBZ and ECarboF groups (36% versus 38%, P 1⁄4 0.89). Median progression-free survival (PFS) was 2.7 months (95% CI 2.0e4.9) for CBZ versus 5.3 months (95% CI 2.6e8.0) for ECarboF. Median overall survival (OS) was 9.3 months (95% CI 6.1e17.6) for CBZ versus 13.1 months (95% CI 7.6e27.2) for ECarboF. Therewas a significant difference in PFS in the ECarboF group (HR 1⁄4 0.42; 95% CI 1⁄4 0.24e0.75; P 1⁄4 0.004), and a non-significant trend towards better OS (HR 1⁄4 0.58; 95% CI 1⁄4 0.29e1.14; P 1⁄4 0.114). Conclusion: Patients in the CBZ group were more heavily pre-treated than those in the ECarboF group, probably contributing to improved PFS and OS in ECarboF patients. However, both chemotherapy regimens have activity in the post-docetaxel setting.