Anlotinib plus TQB2450, a PD-L1 Antibody, in Patients with Advanced Alveolar Soft Part Sarcoma: A Single-Arm, Phase II Trial.

PURPOSE

Alveolar soft part sarcoma (ASPS) is an ultrarare soft-tissue sarcoma with a high rate of metastasis and no established treatment. This study aimed to explore the efficacy and safety of anlotinib (a tyrosine kinase inhibitor) and TQB2450 (a PD-L1 inhibitor) in patients with ASPS.

PATIENTS AND METHODS

This single-arm, phase II study evaluated the efficacy of TQB2450, an anti-PD-L1 agent, combined with anlotinib, a tyrosine kinase inhibitor, in adults with advanced ASPS. TQB2450 was given intravenously (1,200 mg) on day 1, and anlotinib (12 mg/day) was taken orally from day 1 to 14 every 3 weeks. The primary endpoint was overall response rate, with secondary endpoints including duration of response, progression-free survival, and overall survival. Lymphocyte infiltration and tertiary lymphoid structure (TLS) were also analyzed as potential prognostic biomarkers.

RESULTS

The study enrolled 29 patients, of whom 28 were evaluable (one withdrew because of acute pancreatitis). An objective response was achieved in 82.1% of patients, including 4 complete and 19 partial responses. The median time to response was 2.8 months, and the duration of response was not reached, with an estimated median progression-free survival of 35.2 months. Grade 3 to 4 treatment-related adverse events occurred in 44.8% of patients, with no study-related deaths. Responders had a higher proportion of TLS area, TLS density, and CD20-positive immune cells.

CONCLUSIONS

The combination of anlotinib and TQB2450 is effective and tolerable in patients with ASPS. TLS may serve as a prognostic biomarker, meriting further investigation.