Efficacy and safety of anlotinib plus TQB2450 in patients with advanced soft tissue sarcoma: A multicenter, single armed, phase 1b trial.

11547 Background: Anlotinib, a multitargeted tyrosine kinase inhibitor, had been prove to be effective for the treatment of advanced or metastatic soft tissue sarcoma(STS) faild anthracycline chemotherapy. With the lack of prospective data of combination of PDL-1 inhibitor and antiangiogenic agent, we designed a phase 1b study to investigated the efficacy and safety of anlotinib plus TQB2450 in patients with STS. Methods: Eligible patients (age 18-70, ECOG 0-1, with histopathologically confirmed advanced STS, at least one measurable lesion according to RECIST 1.1, and previously received front-line anthracycline chemotherapy) were included and received anlotinib (12mg qd, D1-14, 21d/cycle) plus TQB2450 (1200 mg, IV, D1, 21d/cycle) until disease progression or intolerable toxicities.The primary endpoint was objective response rate (ORR), secondary endpoints included safety, overall survival (OS), progression-free survival (PFS), disease control rate (DCR). Results: From January 2019 to January 2021, 30 pts were enrolled1, 12 alveolar soft part sarcoma and 18 others (7 synovial sarcoma, 4 leiomyosarcoma, 5 undifferentiated pleomorphic sarcoma, 1 fibrosarcoma and 1 epithelioid sarcoma). ORR by RECIST was 36.7%, DCR was 83.3%, 11/30 pts had PR, 14/30 (46.7%) had SD, 5/30 (16.7%) PD. Median PFS was 9.6 m in all pts and 4.9m. in non-ASPS, respectively. Median OS in non-ASPS was 10.27m, while mOS in all pts and both mPFS and mOS in ASPS had not been reached. Notably, to ASPS pts, ORR was 75%, and DCR was 100%. The most common 1-2 grade treatment-related adverse reaction (TRAE) was hypothyroidism (19/30,63.3%)，hypercholesterolemia (16/30, 53.3%) and hypertriglyceridemia (16/30, 53.3%), the most common ≥3 grade TRAEs were hypertriglyceridemia (3/30, 10%). 6 SAE (20%) occurred, including 2 pneumothorax, 1 Immune associated hapatic injury, 1 hypotension, 1 Immune myocarditis and 1 diabetic ketoacidosis. Conclusions: The combination of anlotinib and TQB2450 showed promising activity in second-line treatment of advanced STS, especially in ASPS, with well tolerance and acceptable toxicity.