Making genuine progress against metastatic breast cancer

This review highlights the considerable complexity involved in assessing meaningful clinical benefit on the basis of current FDA criteria for assessing net benefit over harm. A significant impact on OS should remain the gold standard for drug approval in first-line MBC. A substantial increase in PFS with a strong trend or actual significant improvement in OSor reliable measures of quality of life providing an acceptable balance of efficacy and safety may also provide a reasonable measure of clinical benefit. The danger is not in setting the bar reasonably high but in not coming to agreement on what that bar is and what is required to cross it.