Adjuvant Maintenance Larotrectinib Therapy in 2 Children With NTRK Fusion-positive High-grade Cancers

Area of Science:

• Pediatric Oncology
• Molecular Oncology
• Cancer Therapeutics

Background:

• Treatment-related morbidity necessitates research into targetable lesions in pediatric cancers.
• Neurotrophic tropomyosin receptor kinase (NTRK) alterations are found in approximately 1% of pediatric solid tumors.
• Early trials of NTRK inhibitors for progressive NTRK-mutated cancers in children show encouraging outcomes.

Observation:

• This study details the use of adjuvant maintenance larotrectinib following surgical resection in two toddlers with NTRK fusion-positive malignancies.
• The cases involved an ETV6-NTRK3 fusion-positive undifferentiated embryonal sarcoma of the kidney and a NACC2-NTRK2 fusion-positive anaplastic astrocytoma.

Findings:

• Both pediatric patients remain alive and in remission 15 months post-treatment.
• Patients are developing normally and tolerating larotrectinib well.
• The treatment regimen demonstrated efficacy in managing aggressive pediatric cancers with high recurrence rates.

Implications:

• This case series expands the therapeutic applications of NTRK inhibitors.
• Adjuvant maintenance larotrectinib represents a potential strategy for improving outcomes in pediatric NTRK fusion-positive cancers.
• Further investigation into this treatment approach is warranted for similar pediatric malignancies.