Target-driven exploratory study of imatinib mesylate in children with solid malignancies by the Innovative Therapies...

Area of Science:

• Pediatric Oncology
• Pharmacology
• Molecular Targeted Therapy

Background:

• Refractory/relapsing solid tumors in children and adolescents often lack effective treatment options.
• Targeting receptor tyrosine kinases like KIT and PDGFR is a strategy for cancer therapy.
• Imatinib is a tyrosine kinase inhibitor with demonstrated efficacy in certain adult malignancies.

Purpose of the Study:

• To evaluate the efficacy and pharmacokinetics of imatinib in pediatric patients with refractory/relapsing solid tumors.
• To assess imatinib's activity in tumors expressing imatinib-sensitive receptor tyrosine kinases (KIT, PDGFR).

Main Methods:

• An exploratory study involving 36 pediatric patients with brain, mesenchymal/bone, or other solid tumors.
• Tumors were assessed for KIT, PDGFRA, and PDGFRB expression.
• Standard radiological response evaluation, pharmacokinetic analysis, gene mutation analysis, and positron emission tomography (PET) imaging were performed.

Main Results:

• Thirty-six patients received imatinib (340 mg/m²/d).
• Fifteen tumors expressed KIT, 19 PDGFRA, and 25 PDGFRB.
• Ten patients achieved stable disease; one chordoma showed a metabolic response. Pharmacokinetic data revealed high inter-patient variability.

Conclusions:

• Imatinib was generally well-tolerated in pediatric patients.
• The study did not demonstrate significant clinical efficacy of imatinib in pediatric solid tumors expressing KIT or PDGFR according to standard response criteria.