Cabazitaxel in docetaxel-pretreated metastatic castration resistant prostate cancer (mCRPC): Canadian experience.

Abstract

e16082 Background: Cabazitaxel/prednisone (CbzP) improves survival in docetaxel resistant mCRPC. Canadian investigators collected safety, QoL and efficacy data in patients (pts) from a global Expanded Access Program. Methods: Following progression on or after docetaxel, all pts received cabazitaxel 25 mg/m² IV q3wkly and prednisone 10 mg daily. Safety and QoL were collected at baseline and at each cycle. Adverse events were graded according to NCI CTCAE v 4.0. Present pain intensity (PPI) and analgesic scores were assessed using the McGill-Melzack questionnaire. QoL was assessed using FACT-P and EQ 5D-3L. PSA was done at the investigator's discretion at each cycle and at the end of treatment. Results: 61 pts were enrolled at 9 centers. Median age was 65 (18% ≥ 75); 92% were ECOG 0/1; 89% had bone metastases and 21% had visceral metastases. Pts had a median of 9 cycles (median cumulative dose 675 mg/m2) of prior docetaxel, and 38% had progressed on or within 3 months of it. Notably 26 pts (43%) had also received and progressed on prior Abiraterone Acetate (AA) given before (5pts), or after docetaxel (21 pts). Half the patients (51%) received >6 cycles of CbzP. Median relative dose intensity was 99%. At cycle 1, 31% received prophylactic G-CSF. Main grade 3+ toxicities were anemia 9.8%, diarrhea 8.2%, fatigue 8.2% and febrile neutropenia 6.6%. Peripheral neuropathy was uncommon (4.9% ; no grade 3+). There was 1 treatment related death (1.6%) due to abdominal sepsis. Compared to baseline, PPI scores improved despite stable analgesic use and were significant at cycles 2, 4, 9 (p<0.05). The FACT-P prostate specific questions showed significant improvements in the first 4 cycles (p<0.05). On the EQ-5D-3L the percentage of patients reporting “no problem” for the pain domain by the last cycle increased. The PSA response rate (≥50% decrease) was 48.7% in 39 evaluable pts and was similar in AA pretreated and non-pretreated pts (47.1% and 50.0% respectively). Conclusions: In routine clinical practice, CbzP treatment was clinically manageable and toxicities were similar to the TROPIC study. PPI and QoL data support a palliative benefit of CbzP. PSA response rate was 48.7% and similar in AA pretreated and non-pretreated pts.