Long-term response to sunitinib treatment in metastatic renal cell carcinoma (mRCC).

598 Background: A subset of patients (pts) with mRCC treated with sunitinib achieves a long-term response. This study aimed to characterize the duration of treatment and clinical outcomes of pts with mRCC who were long-term responders (LTRs), defined as pts who had progression-free survival (PFS) > 2 years, while on sunitinib therapy. Methods: A retrospective analysis of data from 5714 pts with mRCC treated with sunitinib in 8 phase II or III clinical trials and pts treated in the expanded access program (EAP). Data on treatment duration and response to treatment were compared between LTRs and pts who had PFS ≤ 2 years (others). Results: A total of 529 (9.3%) pts achieved a long-term response, 5162 (90.3%) achieved other response, and data were missing for 23 (0.4%) pts. Overall, 309 (5.4%) pts achieved PFS between >2 and ≤3 years, 125 (2.2%) pts achieved PFS between >3 and ≤4 years, 62 (1.1%) pts achieved PFS between >4 and ≤5 years, and 33 (0.6%) pts achieved PFS between >5 and ≤6 years. The median (ran...