Progression-free survival as a surrogate endpoint of overall survival in patients with metastatic renal cell carcinoma

Abstract

BACKGROUND The current study was conducted to investigate the dependence between progression-free survival (PFS) and overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) and to explore whether PFS can be used as an intermediate endpoint of OS in this patient population. METHODS A total of 1381 patients from 2 prospective phase 3 trials (Cancer and Leukemia Group B [CALGB] 90206 and AVOREN) of interferon-alpha with or without bevacizumab were analyzed. Both trials recruited previously untreated patients with clear cell mRCC with an Eastern Cooperative Oncology Group performance status of 0 to 2; adequate bone marrow, hepatic, cardiac, and renal function; and controlled blood pressure. The CALGB study served as the training data set, and the AVOREN study served as the testing data set. The dependence between PFS and OS was investigated using the Kendall tau for bivariate time-to-event endpoints. RESULTS In the training data set, the median OS times among patients who experienced progressive disease at 3 months or 6 months were 6 months and 8 months, respectively, compared with 25 months and 30 months, respectively, (P