Sintilimab (PD-1 antibody) plus gemcitabine and docetaxel (GT) as first-line or later-line therapy in patients with advanced epithelioid sarcoma: A prospective, multicenter, single-arm, phase II clinical study.

11574 Background: Advanced epithelioid sarcoma (ES) responds poorly to conventional chemotherapy, with an objective response rate (ORR) of 15-27% and a median progression-free survival (mPFS) of only 4-6 months, highlighting the urgent need for new therapeutic strategies. This study aims to evaluate the efficacy and safety of Sintilimab (An approved PD-1 antibody) plus the gemcitabine and docetaxel (GT) in patients with advanced ES that has not been treated by chemotherapy. Methods: This is a single-arm, prospective phase II study conducted in China (ChiCTR2500095527). Patients received Sintilimab (200mg, d1, q3w) combined with gemcitabine (1000mg/m², d1,8, q3w) and docetaxel (70mg/m², d8, q3w) for up to 6 cycles, followed by Sintilimab maintenance for up to 2 years or until disease progression, intolerable adverse reactions or death. The primary endpoint was ORR, and secondary endpoints included PFS, overall survival (OS), and safety. Additionally, tumor tissue and/or blood samples were collected from patients before treatment and at the time of progression for exploratory biomarker analysis. Results: Between October 2024 and January 2026, Of the 19 planned patients, 16 eligible patients were enrolled. The median age was 36 years (range: 22-61), with 5 males and 11 females. All patients had metastatic or unresectable locally advanced disease (ECOG performance status 0: 12.5%; stage IV: 75.0%). With the cutoff date of January 15, 2026, 14 patients were evaluated, the median follow-up time was 8.6 months (range, 2.9 to 14.6 months), the objective response rate (ORR) was 35.71% (5/14), all of them were partial responses (PR), and the disease control rate (DCR) was 100% (14/14). The median PFS and OS were not reached. Treatment-related adverse events (TRAEs) occurred in all patients, with grade ≥3 TRAEs observed in 4 (28.57%) patients, included two case of neutropenia, and one case each of thrombocytopenia and transaminase elevation. Conclusions: The combination of Sintilimab and GT demonstrated promising efficacy in chemotherapy-naïve patients with advanced ES, achieving an ORR of 35.71% and a remarkably high DCR. Despite limited follow-up, the preliminary PFS data suggest a potential benefit from PD-1 immunotherapy. The combination showed a manageable safety profile with no new safety signals identified. Clinical trial information: ChiCTR2500095527.