Dr. Lassen Discusses TRK Fusions in Pediatric Patients

Ulrik Lassen, MD, PhD, head of the Phase I Unit at Rigshospitalet, discusses TRK fusions in pediatric patients with cancer.

TRK fusions are seen quite rarely in common adult cancers, Lassen says, which makes clinical trial enrollment solely for adults a challenge. Although pediatric cancers are less common compared to adult cancers, TRK fusions are commonly seen in pediatric cancer. For example, Lassen states that more than 75% of patients with infantile sarcoma harbor TRK fusions. Therefore, pediatric patients were included in the study of larotrectinib (LOXO-101).

Pooled results from 3 trials of larotrectinib across adult and pediatric tumors showed that the TRK inhibitor was associated with an objective response rate of 80%. Follow-up data presented at the 2018 ESMO Congress showed complete responses in 10 of 55 patients and partial responses in 34.

A priority review to a new drug application for larotrectinib was granted by the FDA in May 2018. If approved, it will be indicated for the treatment of adult and pediatric patients with locally advanced or metastatic solid tumors with an NTRK gene fusion.