Safety and efficacy of Pazopanib in advanced soft tissue sarcoma: PALETTE (EORTC 62072) subgroup analyses

Background: PALETTE is a phase 3 trial that demonstrated single-agent activity of pazopanib in advanced soft tissue sarcomas (aSTS). We performed retrospective subgroup analyses to explore potential relationships between patient characteristics, prior lines of therapy, dose intensity, and dose modifications on safety and efficacy of pazopanib in aSTS. Methods: PALETTE compared pazopanib with placebo in patients with aSTS (age ≥ 18 years) whose disease had progressed during or following prior chemotherapy. In these subgroup analyses, median progression-free survival (mPFS) among patients receiving pazopanib was the efficacy outcome of interest. Adverse events (AEs) were also compared within subgroups. All analyses were descriptive and exploratory. Results: A total of 246 patients received pazopanib in the PALETTE study. The mPFS was longer in patients who had only 1 prior line versus 2+ prior lines of therapy (24.7 vs 18.9 weeks, respectively); AE rates were similar regardless of number of prior lines of therapy. The mPFS was similar in patients aged < 65 and ≥ 65 y (20.0 and 20.1 weeks, respectively). Although AEs leading to study discontinuation were higher in older patients (≥65 y, 30%; < 65 y, 17%), rates of dose reductions, dose interruptions, and serious AEs were similar between the 2 age groups. No reduction in mPFS was noted in patients requiring dose reductions or dose interruptions to manage toxicities. Conclusions: Longer mPFS was observed in patients receiving pazopanib following only 1 line of therapy. Additionally, mPFS with pazopanib was maintained regardless of patient age or dose modifications used to manage toxicity. Trial registration: NCT00753688, first posted September 16, 2008 (registered prospectively).