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

NCT06902792 | Enrolling By Invitation Phase 1

• 1 other identifier: SAHoWMU-CR2025-06-103
• Study Type: interventional
• Target: 6
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Histiocytosis, Langerhans-Cell

Outcome Measures

Primary Outcomes (1)

• Disease Activity Score

  The Disease Activity Score included the following parameters: bone pain, compression of other organs (orbits or spine), fever \>38.5°C, lung imaging findings (pneumothorax, interstitial lesions), lung function (mechanical ventilation, pulmonary function tests \[PFTs\], oxygenation status, cyanosis), percentage of skin area affected, maximum diameter of soft tissue tumors (cm), presence of nodules \>2 cm, liver location (below or above the umbilicus or no enlargement), spleen enlargement (assessed using the same criteria as the liver), hepatic enzymes \>10 times the upper limit of normal, gamma-glutamyl transpeptidase (GGT) \>10 times the upper limit of normal, serum albumin (g/L), platelet count, and hemoglobin (g/L).

  Before the 1st, 2nd, 3rd, 4th, 5th, and 6th cycles(each treatment cycle consists of four weeks), 1 week after discontinuation, 3 months, 6 months, 1 year, 2 years, 3 years

Study Arms (1)

Adebrelimab

EXPERIMENTAL

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.

Drug: treated group

Interventions

treated group DRUG

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.

Adebrelimab

Eligibility Criteria

• Age: Up to 18 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Diagnosis and Grouping Criteria for LCH: Pathological confirmation of LCH via lesion biopsy, with positive immunohistochemistry for CD1a and/or CD207 (Langerin). Diagnostic and grouping criteria adhere to the 2009 standards established by the International Organization Cell Association and the CCHG-LCH-2019 research protocol by the Chinese Children's Histiocyte Group (CCHG). Disease assessment and treatment efficacy are evaluated based on the criteria set by the Society of Tissue and Cell Biology and the CCHG-LCH-2019 protocol. Treatment efficacy is categorized as: (1) No Active Disease (NAD); (2) Active Disease Better (AD-B); (3) Active Disease Stable (AD-S); (4) Active Disease Intermedia (AD-I); (5) Active Disease Worse (AD-W); (6) Relapse: Recurrence of new lesions after achieving NAD, AD-B, or AD-S, following maintenance treatment for over 3 months; (7) Refractory Disease: For SS-LCH patients, if the evaluation after first-line treatment results in AD-I or AD-W, and second-line treatment with cladribine or clofarabine still yields AD-I or AD-W; or MS-LCH patients with AD-I or AD-W after first-line treatment.
• Treatment responses are classified into three categories: favorable response (NAD and AD-B), moderate response (AD-I and AD-S), and adverse response (disease progression or relapse). The overall response rate (ORR) is defined as the percentage of patients achieving a favorable response (NAD or AD-B) at the evaluation time point among all enrolled patients.
• Refractory or Recurrent LCH Criteria: Cases must meet at least one of the criteria for refractory or recurrent LCH.
• Age Criteria: Initially, patients aged 6-17 years were included; subsequently, the age range was expanded to 1-17 years.
• Informed Consent: All patients or their legal guardians must provide signed informed consent.
• Performance Status: ECOG Performance Status (PS) score of 0-1; alternatively, a Karnofsky/Lansky Performance Status Scale score ≥ 50%.
• Expected Survival: Minimum expected survival time of ≥ 6 months.
• Organ Function Requirements:
• Cardiac Function: Left ventricular ejection fraction ≥ 50% on echocardiography, with no significant abnormalities on electrocardiogram.
• Renal Function: Serum creatinine ≤ 2.0 × ULN.
• Hepatic Function: ALT and AST ≤ 5.0 × ULN; total bilirubin ≤ 2.5 × ULN (≤ 3.0 × ULN for Gilbert syndrome). For patients with histiocytosis-related liver disease, abnormal bilirubin, AST, ALT, and albumin levels are permissible.
• Bone Marrow Function: Absolute neutrophil count (ANC) ≥ 1.0 × 10\^9/L, hemoglobin ≥ 80 g/L (red blood cell transfusion allowed), and platelets ≥ 75 × 10\^9/L (transfusion-independent, defined as no platelet transfusion within 7 days prior to enrollment).
• Oxygenation Status: Blood oxygen saturation \> 91% in room air.

You may not qualify if:

• Prior use of monoclonal antibodies or targeted therapies similar to anti-PD-1 or anti-PD-L1 agents.
• Concurrent participation in other clinical trials.
• Persistent treatment-related toxicity \> Grade 1 (per CTCAE V5.0 criteria), excluding alopecia and neurotoxicity.
• Known hypersensitivity to the active ingredients or excipients of trametinib and/or Adebrelimab.
• History of autoimmune diseases, including but not limited to systemic lupus erythematosus, psoriasis, rheumatoid arthritis, inflammatory bowel disease, or Hashimoto's thyroiditis.
• History of or current active tuberculosis infection.
• Active infections requiring systemic treatment.
• Severe comorbid conditions, including but not limited to uncontrolled diabetes or active peptic ulcer disease.
• Positive serology for HIV, TP, HCV antibodies, HBV Ag, or HBV DNA copy number exceeding the upper limit of normal.
• Thyroid dysfunction (abnormal FT3, FT4, T3, or T4 levels).
• Administration of live or attenuated vaccines within 4 weeks prior to treatment initiation, during treatment, or within 5 months after the last dose.
• Any condition deemed by the investigator to render the patient unsuitable for the study.
• Inability or unwillingness to comply with the study protocol due to personal reasons.

Sponsors & Collaborators

• Second Affiliated Hospital of Wenzhou Medical University: lead

Study Sites (1)

Second Affiliated Hospital of Wenzhou Medical University

Wenzhou, Zhejiang, China

Location

MeSH Terms

Conditions

Histiocytosis, Langerhans-Cell

Condition Hierarchy (Ancestors)

Lung Diseases, Interstitial; Lung Diseases; Respiratory Tract Diseases; Histiocytosis; Lymphatic Diseases; Hemic and Lymphatic Diseases

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 10, 2025
• First Posted: March 30, 2025
• Study Start: February 6, 2025
• Primary Completion: August 6, 2025
• Study Completion: February 2, 2026
• Last Updated: March 30, 2025

Record last verified: 2025-03

Locations

CN (1)