A randomized, double-blind, placebo-controlled, Phase III study of pazopanib in patients with soft tissue sarcoma: results from the Japanese subgroup

Objective: This analysis of the Japanese subpopulation of the PALETTE Phase III, randomized, placebo-controlled study investigated efficacy and safety of pazopanib in patients with metastatic soft tissue sarcoma after failure of standard chemotherapy.

Methods: Patients were randomly assigned in a 2:1 ratio to receive either pazopanib 800 mg once daily or placebo, with no subsequent cross-over. Primary endpoint was progression-free survival. Secondary endpoints included overall survival and overall response rate. Efficacy analysis was by intent-to-treat. Safety was also investigated.

Results: Forty-seven patients received either pazopanib (n = 31) or placebo (n = 16). Median progression-free survival was 7.0 weeks (95% confidence interval: 4.0-11.7) for placebo and 24.7 weeks (95% confidence interval: 8.6-28.1) for pazopanib (hazard ratio = 0.41 [95% confidence interval: 0.19-0.90]; P = 0.002). Median overall survival was 14.9 months (95% confidence interval: 6.8-not calculable) for placebo and 15.4 months (95% confidence interval: 7.9-28.8) for pazopanib (hazard ratio = 0.87 [95% confidence interval: 0.41-1.83]; P = 0.687). More patients receiving pazopanib experienced best response of stable disease versus placebo. Adverse events were similar to the global population; those leading to dose reduction were more common and mean daily dose was lower in the Japanese population versus the global population (45 vs. 32% and 624.4 vs. 700.4 mg, respectively).

Conclusions: The efficacy and safety of pazopanib observed in the Japanese subpopulation of PALETTE were similar to those in the global population. Pazopanib is a new treatment option for Japanese patients with metastatic non-adipocytic soft tissue sarcoma after chemotherapy.

Clinical trial registration number: NCT00753688; GSK study ID: VEG110727; http://www.gsk-clinicalstudyregister.com/study/VEG110727#ps.