Anlotinib plus toripalimab in patients with advanced bone and soft tissue sarcomas including ultra-rare sarcomas: A multicenter, single-arm, phase 2 trial.

BACKGROUND

Treatment options for advanced sarcomas, particularly ultra-rare sarcomas (URS), remain limited. This study evaluated the activity and safety of anlotinib combined with toripalimab in a histologically diverse sarcoma population.

METHODS

This single-arm, phase 2 clinical trial was conducted at four centers in China. Participants received anlotinib (12 mg on days 1-14) in combination with toripalimab (240 mg on day 1) every 3 weeks. The primary endpoint was objective response rate (ORR) by RECIST 1.1. Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Of 70 enrolled patients, 68 were evaluable for activity. The cohort included 34 (48.6%) patients with URS. At a median follow-up of 29.6 months, confirmed ORR was 29% (95% CI: 19-42%) and DCR was 90% (95% CI: 80-96%). Median PFS was 7.0 months and median OS was 27.0 months. In patients with soft-tissue URS (n = 31), ORR was 39% and median PFS was 11.0 months. Treatment-related grade ≥ 3 adverse events included hypertension (15.7%), hand-foot syndrome (12.9%), and hypertriglyceridemia (7.1%). Exploratory post-hoc analysis identified baseline monocyte count was independently associated with PFS and OS; responders had significantly lower baseline monocytes than non-responders.

CONCLUSIONS

These single-arm, exploratory findings demonstrate clinically promising anti-tumor activity for anlotinib plus toripalimab with manageable toxicity in heavily pretreated, histologically diverse advanced sarcomas, highlighting its potential in URS and identifying monocytes as a pragmatic, non-invasive biomarker worthy of further validation.