Background: Pemetrexed and carboplatin have demonstrated activity in breast cancer. Their potential synergism in experimental models and the proven efficacy of pemetrexed/platinum in other indications make pemetrexed/carboplatin an attractive combination in breast cancer. Thus, this two-stage, sequential, open-label, multicenter, phase II study assessed the efficacy and safety of pemetrexed plus carboplatin as first-line therapy in patients with locally advanced breast cancer (LABC) or metastatic breast cancer (MBC).
Patients and methods: Patients >or= 18 years with a histologic/cytologic diagnosis and no prior chemotherapy for LABC or MBC received pemetrexed 600 mg/m(2) and carboplatin AUC 5.0 on day 1 every 21 days with folic acid and vitamin B(12) supplementation.
Results: From June 2003 to April 2005, 50 patients with stage IIIB (30.0%) and stage IV (70.0%) disease were enrolled at 3 study centers. Twenty-eight percent of patients previously received adjuvant chemotherapy, 46.0% had visceral metastases, and 36.0% had >or=3 organs involved. Partial responses (RECIST criteria) were achieved in 27 (54.0%) patients (ORR = 54.0%; 95% CI, 39.3-68.2%). The median response duration was 11.1 months (95% CI, 6.5-14.0 months) and the median time to disease progression was 10.3 months (95% CI, 8.3-14.6 months). CTC hematologic toxicities were grade 3/4 neutropenia (58.0%/28.0%) and grade 3 thrombocytopenia (10.0%) and anemia (18.0%). Two (4.0%) patients had febrile neutropenia, 1 of whom died. No grade 4 non-hematologic toxicities occurred. Grade 3 non-hematologic toxicities were ALT (4.0%) and AST elevation, and edema, fatigue, pruritus, rash/desquamation, and renal toxicity (2.0% each).
Conclusions: Results of this study suggest that the combination of pemetrexed and carboplatin has promising efficacy and an acceptable safety profile. Further assessment of this combination in a randomized trial of various breast cancer patient populations is warranted.