Study on the Safety and Effectiveness of Larotrectinib for Treating Tumors with NTRK Fusion in Children

Inclusion Criteria

• Children from birth to 21 years old with advanced or spreading solid tumors or primary brain tumors that have not responded to other treatments and have no other standard treatment options.
• Infants with a cancer diagnosis and a confirmed NTRK fusion that has not responded to other treatments.
• Children with locally advanced infantile fibrosarcoma who would need disfiguring surgery or limb amputation to remove the tumor completely.
• Patients with a confirmed NTRK gene fusion, except for those with infantile fibrosarcoma, congenital mesoblastic nephroma, or secretory breast cancer, unless they have specific genetic rearrangements.
• Patients with primary brain tumors or brain metastasis.
• A performance score of at least 50 on the Karnofsky scale (for those 16 and older) or Lansky scale (for those younger than 16).
• Adequate blood, liver, and kidney function.

Exclusion Criteria

• Major surgery within 14 days before starting the study.
• Significant heart disease or heart attack within the last 6 months, ongoing heart muscle disease, or prolonged heart rhythm interval.
• Active, uncontrolled infections.
• Current use of certain medications that affect liver enzymes, except for stable doses of specific anti-seizure drugs and dexamethasone for brain tumors.
• For Phase 2 only: Previous progression while on other TRK-targeting drugs, unless the drug was taken for less than 28 days and stopped due to intolerance.