LAUSR

683Background: Pazopanib, a highly lipophilic standard first-line therapy for metastatic RCC, is conventionally taken in a fasting state but has significant gastrointestinal toxicities and 96% of ingested drug is fecally excreted, with major financial implications. Single dose studies with fat meals suggested bioavailability is increased two-fold. We sought to evaluate toxicity/safety, bioavailability and anti-tumor efficacy of daily pazopanib taken with a low fat meal over 12 weeks. Methods: Enrolled pts had unresectable locally advanced or metastatic RCC with clear cell component, RECIST 1.1 measurable disease, ECOG PS ≤2, adequate organ function, and up to 3 prior therapies including VEGF(R) and checkpoint inhibitors. Subjects took pazopanib, starting dose of 400 mg, once daily with low-fat meal ( < 400 cal with < 20% fat/10 g of fat) in 2 wk cycles with MD discretion to dose-escalate q2wks up to 800 mg or irreversibly dose-reduce as low as 200 mg based on tolerance/toxicity for 12 wks. Baseline and en...