Prediction of personalized therapeutic response in pediatric clivus chordoma: chemoresistance test.

Precision medicine has expanded therapeutic options for rare central nervous system tumors, yet actionable molecular targets remain limited in pediatric cases. Functional ex vivo drug-response assays may complement genomic approaches by identifying tumor-specific sensitivities. Clival chordoma is a rare, locally aggressive tumor generally considered chemotherapy-refractory, particularly in children. We report the prospective use of a functional drug-response platform (Bioverso Test) to guide treatment in a pediatric patient with recurrent metastatic clival chordoma. A four-year-old patient with intracranial and pulmonary disease underwent testing using three-dimensional tumor microspheroids. The assay demonstrated broad resistance, with relative sensitivity to irinotecan (CPT-11). Treatment with an irinotecan-based regimen (50 mg/m²/day, days 1-5) resulted in a marked clinical and radiological response after three cycles, with significant reduction of intracranial and pulmonary lesions and no severe toxicities. The response has been sustained for 14 months. This case illustrates the clinical utility of integrating functional drug-response data into real-time decision-making, supporting a role for functional precision oncology in rare and treatment-refractory pediatric tumors.