US Food and Drug Administration Approval Overview in Metastatic Breast Cancer

We reviewed trials that supported US Food and Drug Administration (FDA) approvals of drugs and biologics for the treatment of metastatic breast cancer (MBC) in the last two decades. This summary provides an overview of the basis for approval, including end points, trial design, major trial findings, and regulatory considerations. Approval of hormonal agents is excluded from this analysis. In the last two decades, 10 products with 14 MBC indications (four for first-line and 10 for second-to third-line treatment) were approved by the FDA. Approval decisions for these 14 indications were supported by a variety of end points that showed a favorable benefit-to-risk profile. Among these 14 indications, four were granted accelerated approval (AA), and 10 were given regular approval (RA). Of the four approved under AA, two have subsequently demonstrated clinical benefit resulting in conversion to RA. We conclude with current FDA thinking on the drug development challenges for the treatment of MBC and recommendations for future trial design.