FDA Approves Letrozole for Treatment of Early-Stage
The FDA last week approved letrozole (Femara) for extended adjuvant treatment of early-stage breast cancer in postmenopausal women treated with tamoxifen for 5 years. The FDA gave the okay for letrozole under an "accelerated approval," requiring the drug's manufacturer, Novartis, to conduct and provide data to the FDA on long-term outcomes.
The approval was based on results from the MA-17 trial, a double-blind, multicenter, international clinical study involving nearly 5,200 postmenopausal women with hormone receptor-positive, early-stage breast cancer who had received 5 years of adjuvant tamoxifen therapy. All of the participants were within 3 months of completion of adjuvant therapy with tamoxifen and were randomly assigned to receive 5 years of letrozole or placebo. The Canadian Cancer Society funded MA-17, which was coordinated by the National Cancer Institute of Canada in partnership with the NCI Clinical Trials Cooperative Groups.
An updated analysis of data from MA-17 - originally published in November 2003 - was presented at ASCO's annual meeting in June. With a median follow-up of 2.5 years, letrozole reduced local and distant recurrences of cancer and new breast cancers, regardless of a patient's node-positive or -negative status at diagnosis. Distant metastases were reduced by about 40 percent compared with placebo, while overall survival was improved by 39 percent for node-positive patients.