BACKGROUND This phase 2, single-arm, multicenter study was designed to determine the treatment activity and safety of single-agent pazopanib in patients with unresectable or metastatic liposarcoma. METHODS Eligible patients had high-grade or intermediate-grade liposarcoma with measurable tumors that were unresectable or metastatic, documented disease progression, and had received any number of prior treatments, excluding previous treatment with a vascular endothelial growth factor inhibitor or a tyrosine kinase inhibitor. Patients received oral pazopanib 800 mg once daily for 28-day cycles. Tumor response was evaluated by local radiology assessments every 3 cycles. The primary endpoint was the progression-free rate (PFR) at 12 weeks (PFR12). RESULTS Forty-one patients were enrolled. The PFR12 was 68.3% (95% confidence interval [CI], 51.9%-81.9%), which was significantly greater than the null hypothesis value of 40% (P = .0002). At 24 weeks, 39% of patients (95% CI, 24.2%-55.5%) remained progression free, and 44% experienced tumor control (partial response or stable disease). The median progression-free survival was 4.4 months (95% CI, 3.2-6.5 months), and the median overall survival was 12.6 months (95% CI, 8.5-16.2 months). The most common adverse events overall were nausea (39%), hypertension (36.6%), diarrhea (34.1%), and fatigue (29.3%), which were typically less than grade 3. There were 5 deaths on study (12.2%), 3 of which were from possible complications of therapy. CONCLUSIONS The current study provides evidence of potential activity of pazopanib in the liposarcoma subset of patients with soft tissue sarcoma that was specifically excluded from the phase 3 PALETTE trial of other soft tissue sarcoma types. Cancer 2017. © 2017 American Cancer Society.