Background: This phase II study evaluated the efficacy, safety, and health outcomes of pemetrexed treatment in heavily pretreated patients with advanced breast cancer.
Patients and methods: Women with metastatic breast cancer, Karnofsky performance status > or = 70, and previous treatment with > or = 3 regimens containing anthracyclines, taxanes, and capecitabine were eligible. Pemetrexed 500 mg/m2 intravenous infusion was administered on day 1 of a 21-day treatment cycle.
Results: Eighty patients were enrolled, and 60 received concurrent folic acid and vitamin B12 supplements per protocol amendment to minimize possible pemetrexed-related toxicity. The median numbers of cycles delivered were 3 for vitamin-supplemented patients and 2 for non-vitamin-supplemented patients. Regardless of vitamin supplementation, the overall response rate was 8% (95% CI, 3%-16.6%), stable disease was exhibited in 36% of patients, median time to disease progression was 2.9 months, and median survival was 8.2 months. Improvements in patient-reported symptoms ranged from 16.2% for pain intensity to 32.1% for nausea. Major grade 3/4 toxicities were hematologic, with grade 4 neutropenia in 10% of patients and grade 3 toxicities consisting primarily of neutropenia (29%) and leukopenia (21%). There were no clear trends of the effect of supplementation on toxicity.
Conclusion: Pemetrexed has modest antitumor activity and is well tolerated in heavily pretreated patients with breast cancer. Further evaluation of this multitargeted antifolate in advanced breast cancer is warranted.