Schmidinger M, et al. - In a prospective, observational study (PRINCIPAL), researchers sought to validate real-world safety and efficacy of pazopanib in patients with advanced renal cell carcinoma (RCC). Eligibility criteria permitted inclusion of patients with clear cell advanced/metastatic RCC and a clinical decision to initiate pazopanib therapy within 30 days of enrollment; overall 657 patients were enrolled. These were given ≥1 dose of pazopanib. The estimated median progression-free survival (PFS) was 10.3 months and overall survival (OS) was 29.9 months. A 30.3% of objective response rate (ORR) was reported, as well as little or no deterioration of health-related quality of life (HRQoL) over time. A total of 64 (9.7%) patients suffered treatment-related serious adverse events (AEs) and 399 (60.7%) patients experienced AEs of special interest. More patients were classified non-clinical-trial-eligible (NCTE) than clinical-trial-eligible (CTE) (85.2% vs 14.8%). Both the groups demonstrated similar efficacy of pazopanib. In PRINCIPAL, pazopanib was confirmed as an effective and safe treatment option for advanced/metastatic RCC in a real-world clinical setting.