A randomized phase II non-comparative study of pemetrexed carboplatin and gemcitabine vinorelbine in anthracycline- and taxane-pretreated advanced breast cancer patients

Pemetrexed-carboplatin and gemcitabine vinorelbine combination therapies were efficacious in phase II and phase III studies as first-line breast cancer treatment. Thus, Arm A and Arm B combinations were investigated in patients pretreated with anthracycline and taxanes. Women with advanced breast cancer, with ≥1 measurable lesion per RECIST, were stratified by line of treatment (1st, 2nd), visceral disease (yes/no), ECOG PS (0-1 vs. 2) and randomized 1:1 to Arm A (pemetrexed 600 mg/m², D1 i.v. q21; carboplatin, AUC 5, D1 i.v. q21) or Arm B (gemcitabine 1,200 mg/m² D1, D8 i.v. q21; vinorelbine 30 mg/m² D1, D8 i.v. q21). Treatment continued until progression. The primary endpoint was objective response rate (RR). Secondary endpoints were duration of response (DoR), time-to-response (TTR), time-to-progressive disease (TTPD), time-to-treatment failure (TTTF) and safety. A two-stage design was employed independently for each arm. Of 135 randomized patients, 125 (Arm A, n=64; Arm B, n=61) qualified for tumor-response analysis. The mean (standard deviation) number of cycles administered was 6.3 (4.13) in Arm A and 6.2 (4.39) in Arm B. Efficacy in Arm A and Arm B were: RR (95% CI), 26.6 (16.3-39.1) and 29.5 (18.5-42.6); time-to-events (months), DoR 7.7 and 7.5; TTPD, 5.1 and 5.6; TTR, 1.8 and 1.8; TTTF, 4.8 and 5.1; respectively. Most common grade 3/4 adverse events possibly related to study-drug were neutropenia, thrombocytopenia, anemia and leucopenia in Arm A and neutropenia, leucopenia and fatigue in Arm B. In this study, both combinations showed moderate activity as predefined RR was not reached and were well tolerated.