Adebrelimab Combined With Trametinib in the Treatment of Refractory Recurrent Langerhans Cell Histiocytosis in Children and Adolescents

Phase 1, 1 case in total Subject 1: This study marks the first application of Adebrelimab in pediatric patients with Langerhans Cell Histiocytosis (LCH). The initial dose is 20 mg/kg, delivered via a 60-minute intravenous infusion. If no Dose-Limiting Toxicity (DLT) occurs, the second dose of 20 mg/kg will be administered in the second cycle. Treatment cycles consist of dosing every 4 weeks, up to a maximum of 6 cycles. Phase 2, 2-5 cases in total Subjects 2 and 3: If the first subject exhibits no DLT, the second and third subjects will be enrolled and receive 20 mg/kg of Adebrelimab on day 1. Treatment cycles will last 4 weeks, with dosing administered every 4 weeks, for up to 6 cycles. Subjects 4-6: If one DLT occurs among the first three subjects, three additional subjects will be enrolled and given 20 mg/kg of Adebrelimab. If two or more DLTs occur among the first three subjects, three additional subjects will be enrolled and administered a reduced dose of 10 mg/kg. Following the successful completion of these phases, a subsequent phase will commence to further assess the efficacy and safety of Adebrelimab and fulfill the biological research objectives.