Durvalumab and pazopanib in patients with advanced soft tissue sarcoma: A single-center, single-arm, phase 2 trial.

11551 Background: Based on the central role played by the vascular endothelial growth factor receptor (VEGFR) in immunosuppression, we assessed the activity and safety of VEGFR inhibitor pazopanib plus anti-PD-L1 blockade durvalumab in soft tissue sarcoma (STS). Methods: We did a single-arm, single-center, phase 2 study that enrolled patients with metastatic or locally advanced STS aged 19 years or older, ECOG PS 0-1, with at least one measurable lesion, and received at least one previous line of systemic therapy. Patient were given pazopanib 800 mg orally daily and durvalumab 1500 mg intravenously for 60 min every 3 weeks. The primary endpoint was investigator-assessed objective response. Results: Between September 2019 and October 2020, 47 participants were enrolled, of whom 46 (97.9%) were evaluable for the efficacy analyses. With a median follow up of 12.3 months, complete and partial response (PR) was achieved in 1 (2.2%) and 12 (26.1%) patients, resulting in 28.3 % of objective response rate. Median time to achieve PR was 1.4 months and median duration of response was 11.0 months. The most common treatment-related adverse events of any grade include fatigue (20 [42.6%]), anorexia (17 [36.2%]), diarrhea (17 [36.2%]), and AST elevation (16, [34.0%]). Thirty-one patients (67.3%) had progressive disease, and the median progression free survival was 8.6 months (95% CI 3.6-13.6). Conclusions: Durvalumab and pazopanib showed encouraging activity in patients with advanced STS. Molecular predictors with whole exome and RNA sequencing will be presented. Clinical trial information: NCT03798106.