Randomized phase III trial of ixabepilone plus capecitabine versus capecitabine in patients with metastatic breast cancer previously treated with an anthracycline and a taxane.

Purpose: We sought to determine whether the combination of ixabepilone plus capecitabine improved overall survival (OS) compared with capecitabine alone in patients with metastatic breast cancer (MBC) previously treated with anthracyclines and taxanes.

Patients And Methods: A total of 1,221 patients with MBC previously treated with anthracycline and taxanes were randomly assigned to ixabepilone (40 mg/m(2) intravenously on day 1) plus capecitabine (2,000 mg/m(2) orally on days 1 through 14) or capecitabine alone (2,500 mg/m(2) on the same schedule) given every 21 days. The trial was powered to detect a 20% reduction in the hazard ratio (HR) for death.

Overall survival: still the gold standard: why overall survival remains the definitive end point in cancer clinical trials.

Overall survival (OS) is the gold standard primary end point to evaluate the outcome of any drug, biologic, intervention, or procedure that is assessed in oncologic clinical trials. OS is universally recognized as being unambiguous, unbiased, with a defined end point of paramount clinical relevance, and positive results provide confirmatory evidence that a given treatment extends the life of a patient. Clinical trialists relentlessly attempt to devise more easily measured, cost-effective, and readily available event-driven end points as predictive surrogates of a definitive outcome, such as OS, and reduce the time with which clinical trials deliver definitive results.