Safety and efficacy of sintilimab versus pembrolizumab in the treatment of advanced or recurrent pediatric malignancies: A real-world study in China.

e22010 Background: PD-1 inhibitors have shown durable response and mild adverse events in adult malignancies. Studies of a direct comparison of distinct PD-1 inhibitors in the pediatric tumor setting is lacking.This study compared the safety and efficacy of Sintilimab versus Pembrolizumab in advanced or recurrent pediatric malignancies. Methods: We performed a retrospective analysis on pediatric patients with advanced or recurrent malignancies who received either Sintilimab or Pembrolizumab. The endpoints comprised treatment-related adverse events (TRAEs) and objective response rate (ORR), progression free survival (PFS) and overall survival (OS). Toxicity was evaluated according to the National Cancer Institute's Common Terminology Criteria for Adverse Events, version 5.0. Results: Between April 2017 and August 2024, 75 pediatric patients with advanced or recurrent malignancies treated with Sintilimab (n=53) or Pembrolizumab (n=22) were analysed. The median ages were 8.0 years (range:1-17) for Sintilimab group versus 8.0 years (range:3-17) for Pembrolizumab group. TRAEs following PD-1 inhibitor therapy were shown in table 1.39.7% (29/73) experienced Grade 3-4 hematological TRAEs, mainly including granulocytopenia and anemia. No Grade 3 or higher non-hematological TRAEs were observed. The most common grade 1/2 non-hematologic TRAEs included anorexia (39.7%), increased ALT/AST levels (31.5%), pneumonia (28.8%). Safety profiles were similar between the Sintilimab group and Pembrolizumab group, with all P values >0.05.For those diagnosed with lymphoma (n=13), the ORR were 88.9% (8/9) and 75.0% (3/4) for Sintilimab group and Pembrolizumab group, respectively. The median PFS and OS remained not reached for both Sintilimab group and Pembrolizumab group.For those diagnosed with non-lymphoma malignancies (n=53), the ORR were 40.5% (15/37) and 25.0% (4/16) for Sintilimab group and Pembrolizumab group.In patients with ≤2 treatment lines, PFS and OS were similar between Sintilimab and Pembrolizumab group, with P value of 0.15 versus 0.08.In patients with >2 treatment lines,PFS and OS were also similar between Sintilimab and Pembrolizumab group, with P value of 0.31 versus 0.28. Conclusions: Sintilimab demonstrated favorable tolerability and efficacy in pediatric patients with malignancies, exhibiting a safety and efficacy profile comparable to that of Pembrolizumab. Treatment-related adverse effects following PD-1 inhibitor therapy. Adverse events (Grade 1–2)* Sintilimab groupN (%,N=53) Pembrolizumab group N (%,N=20) P value Hypothyroidism 2(3.8%) 5(25.0%) 0.02 Hyperthyroidism 12(22.8%) 4(20.0%) 1.00 Myositis 1(1.9%) 0 - Pneumonia 18(34.0%) 3(15.0%) 0.11 Increased ALT/AST 15(28.3%) 8(40.0%) 0.34 Gastroenteritis 2(3.8%) 3(15.0%) 0.12 Rash 2(3.8%) 1(5.0%) 1.00 Cardiovascular Adverse Events 14(26.0%) 8(40.0%) 0.26