Objective To evaluate the efficacy and safety of a combination therapy regimen comprising stereotactic body radiation therapy (SBRT) combined with liposomal irinotecan, camrelizumab, and anti-angiogenic therapy (CAP) in patients with advanced bone and soft tissue sarcomas.

Methods This study is a prospective subgroup analysis of the multicenter, open-label, single-arm phase Ⅱ CAP trial (NCT04569916), which enrolled 60 patients with advanced solid tumors who had progressed after standard therapy between November 2020 and February 2023, including 11 patients with advanced bone and soft tissue sarcomas. All patients received sequential liposomal irinotecan within 48 hours after stereotactic body radiotherapy (SBRT), followed by maintenance therapy with camrelizumab and an anti-angiogenic agent until disease progression or intolerable toxicity. The primary efficacy endpoint was objective response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety.

Results In the bone and soft tissue sarcoma subgroup (n=11), three patients achieved partial response (PR), five had stable disease (SD), and three experienced disease progression (PD). ORR was 27.3%, and DCR was 72.7%. mPFS was 5.8 months (95%CI: 2.2-10.3), and mOS not reached. Regarding safety, adverse reactions primarily included bone marrow suppression, fatigue, and gastrointestinal reactions, indicating overall manageable toxicity.

Conclusion As a subgroup analysis of the CAP study, this research suggests that radiotherapy combined with liposomal irinotecan, camrelizumab, and anti-angiogenic therapy demonstrates certain efficacy in advanced bone and soft tissue sarcomas that have failed multiple lines of treatment, with overall manageable adverse reactions. Future studies should expand the sample size.