PHASE-II STUDY OF WEEKLY EDATREXATE AS 1ST-LINE CHEMOTHERAPY FOR METASTATIC BREAST-CANCER - A NATIONAL-CANCER-INSTITUTE OF CANADA CLINICAL-TRIALS GROUP-STUDY

Purpose: The National Cancer Institute of Canada (NCIC) Clinical Trials Group conducted a phase II study to assess the efficacy and toxicity of edatrexate, a folate antagonist, in 35 patients with metastatic breast cancer. Patients and Methods: The planned dose of edatrexate was 80 mg/m2/wk administered intravenously as first-line therapy. Prior adjuvant chemotherapy was allowed provided at least 12 months had elapsed from the completion of treatment to the development of recurrence. Results: Mucositis was the dose- limiting toxicity in 34 assessable patients, resulting in a mean delivered dose-intensity of 57 mg/m2/wk. Other toxicities included myelosuppression, rash, pneumonitis, and increased AST. Side effects were generally mild to moderate. The complete plus partial remission rate (13 patients; 41%) was impressive. Conclusion: Edatrexate is an active agent against metastatic breast cancer, with acceptable toxicity. A lower than planned delivered dose- intensity was mainly due to mucositis.