Long-term response in metastatic renal cell carcinoma patients receiving first-line therapy with VEGF TKIs.

436 Background: A subset of metatstatic renal cell carcincoma (mRCC) patients (pts) on first-line (1st) vascular endothelial growth factor inhibitors (VEGF TKIs) will have a long-term response (LTR) defined as a progression free survival (PFS) of >18 months (mos) on continuous therapy, and may be candidates for intermittent VEGF TKI therapy. Methods: From our institutional dataset of mRCC pts, we identified pts receiving 1st VEGF TKIs and who achieved a LTR. Data on clinical characteristics and survival outcomes were compared between those with LTRs and rest of the patients (control). Continuous and categorical variables were assessed by Wilcoxon rank sum and chi-square, respectively; and survival outcomes were compared by log-rank tests. Results: Of 89 pts, 24 (33%) had LTRs, of whom 5 pts have discontinued treatment (range 1-5 years) without subsequent disease progression, and 4 pts took treatment breaks for 3-9 mos. Baseline pts or disease characteristics were not predictive of LTRs (Table). Conclusion...