A retrospective analysis of the phase III PROTECT study evaluated the relationship between pazopanib exposure in the adjuvant setting and clinical outcomes in renal cell carcinoma. Multivariate analyses revealed that high early (week 3 or 5) or late (week 16 or 20) pazopanib trough concentrations (Ctrough) were significantly associated with improved disease-free survival (P = 0.000758 and P = 0.000496, respectively). Notably, the proportion of adverse event (AE)-related discontinuations or grade 3 or 4 AEs (except hypertension) did not correlate with Ctrough.