Randomized phase II multicenter study of the efficacy and safety of sunitinib on the 4/2 versus continuous dosing schedule as first-line therapy of metastatic renal cell carcinoma: Renal EFFECT Trial.

LBA308 Background: In a randomized phase III trial, sunitinib 50 mg/d on Schedule 4/2 (4 wk on treatment [Tx], 2 wk off) showed superior progression-free survival (primary endpoint) to IFN-α (11 vs. 5 mo; p 2 yr (Motzer 2009). Continuous dosing of sunitinib 37.5 mg has demonstrated antitumor activity with a manageable safety profile in first- and second-line mRCC (Barrios; Escudier, 2009). Methods: This randomized phase II trial compared sunitinib 50 mg/d on Schedule 4/2 (Arm A) vs. 37.5 mg continuous once-daily dosing (Arm B) in first-line mRCC. Eligible patients (pts) had clear cell locally recurrent or mRCC; measurable disease; and Karnofsky performance status ≥70%. Randomization (1:1) was stratified by MSKCC risk groups. Sunitinib was continued until progression, unacceptable toxicity, or up to 2 yr. The primary endpoint was time to tumor progression (TTP) by Kaplan-Meier estimate. Secondary end...