Purpose: The objective of this study was to assess the efficacy and safety of pemetrexed in pretreated patients with advanced-stage breast cancer.
Patients and methods: Patients with advanced-stage or metastatic breast cancer, Eastern Cooperative Oncology Group performance status 0-2, and progressive or relapsed disease after treatment with regimens containing anthracyclines and taxanes were eligible. Pemetrexed 500 mg/m2 was administered as a 10-minute intravenous infusion on day 1 every 21 days.
Results: Seventy-nine women were enrolled. After protocol amendment, 43 patients received folic acid and vitamin B12 supplementation to control pemetrexed-related toxicity. A median of 4 cycles (range, 1-23 cycles) was administered. Overall response rate was 9% (95% confidence interval, 3.7%-17.6%), median duration of response was 5.5 months, median progression-free survival was 3.1 months, and median survival was 10.5 months. Major grade 3/4 toxicities were lymphopenia (53.3%), neutropenia (36.4%), leukopenia (26.9%), and anemia (7.7%). In general, the toxicities were less frequent in patients who received vitamin supplementation than in those who did not receive vitamin supplementation.
Conclusion: The response to pemetrexed salvage treatment was low in this study of heavily pretreated patients with breast cancer. Pemetrexed was generally well tolerated in patients with previously treated breast cancer. Vitamin supplementation appeared to ameliorate toxicity.