A Single-Arm Phase II Trial of Sitravatinib in Advanced Well-Differentiated/Dedifferentiated Liposarcoma

Purpose: To evaluate sitravatinib, an inhibitor of multiple recep-tor tyrosine kinases (RTK), for the treatment of well-differentiated/ dedifferentiated liposarcoma (WD/DD LPS). Patients and Methods: This multicenter, open-label, Phase II trial enrolled patients with advanced WD/DD LPS who had received at least one prior systemic regimen and had progression within 12 weeks of enrollment. Patients received sitravatinib 150 mg (later amended to 120 mg) orally daily. A Simon two-stage design was used to evaluate for an improvement in the primary endpoint, progression-free rate at 12 weeks (PFR12), from 20% to 40%. Secondary endpoints included antitumor activity and safety. A subset of patients under-went paired biopsies analyzed using reverse-phase protein array. Results: Twenty-nine patients enrolled. Median age was 62 years and 31% had received 3 or more prior lines. Most patients (93%) had DDLPS or mixed WD/DD LPS. Overall, 12 of 29 patients (41%) were alive and progression-free at 12 weeks and the study met the primary endpoint. There were no confirmed responses. Median progression-free survival was 11.7 weeks [95% confidence interval (CI): 5.9-35.9] and median overall survival was 31.7 weeks (95% CI: 18.1-90.1). The most common treatment-related adverse events were diarrhea (59%), hypertension (52%), hoarseness (41%), mucositis (31%), and nausea (31%). Baseline expression of phospho-RTKs was not significantly different between patients with and without clinical benefit from sitravatinib, but the number of samples was small. Conclusions: Sitravatinib provided a PFR12 of 41% and mean-ingful disease control in a subset of patients with advanced, pro-gressive WD/DD LPS.