Phase III randomized trial of sunitinib malate (SU11248) versus interferon-alfa (IFN-α) as first-line systemic therapy for patients with metastatic renal cell carcinoma (mRCC)

Abstract

LBA3 Background: Two multicenter phase II trials of 2nd line monotherapy with sunitinib (SU11248) in patients (pts) with mRCC showed a response rate of approximately 40% (JCO 2006;24:16–24; Proc ASCO 23, 380s). This international, randomized phase III trial compared the efficacy and safety of sunitinib to IFN-α in treatment naïve pts with mRCC. Methods: Untreated pts with clear-cell mRCC were randomized 1:1 to receive sunitinib (6-week cycles: 50 mg orally once daily for 4 weeks, followed by 2 weeks off) or IFN-α (6-week cycles: subcutaneous injection 9 MU given three times weekly). The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate, overall survival, and adverse events. Based on a planned sample size of 690 patients, the trial was designed to have 90% power to detect a 35% improvement in median PFS from 20 weeks to 27 weeks (4.6 months to 6.2 months; 2-sided unstratified log-rank test; significance level 0.05). Results of a planned analysis on the primary endpoint, PFS, are presented in this report. Results: From Aug 2004 to Oct 2005, 750 patients were randomized: 375 to sunitinib, 375 to IFN-α. Baseline characteristics were well balanced, and included pooled median age = 60 and prior nephrectomy = 90%. Median PFS assessed by third-party independent review was 47.3 weeks (95% CI 40.9, not yet reached) for sunitinib vs. 24.9 weeks (95% CI 21.9, 37.1) for IFN-α [hazard ratio 0.394 (95% CI 0.297, 0.521) (p < 0.000001)]. The objective response rate by third-party independent review was 24.8% (95% CI 19.7, 30.5) for sunitinib vs. 4.9% (95% CI 2.7, 8.1) for IFN-α (p < 0.000001). The objective response rate by investigator assessment was 35.7% (95% CI 30.9, 40.8) for sunitinib vs. 8.8% (95% CI 6.1, 12.1) for IFN-α (p < 0.000001). 632 pts (85%) are alive, with 49 deaths on sunitinib arm and 65 deaths on IFN-α arm. 8% withdrew from the study due to adverse event on sunitinib arm vs. 13% on IFN-α arm. Conclusions: These results demonstrate a statistically significant improvement in PFS and objective response rate for sunitinib over IFN-α in first-line treatment of pts with mRCC. [Table: see text]