Larotrectinib Products | Cleanchem - Larotrectinib is a highly selective tropomyosin receptor kinase (TRK) inhibitor approved for treating cancers with NTRK gene fusions, regardless of tumor site. It works by blocking TRK fusion proteins that drive cancer cell growth. Larotrectinib has shown durable responses in a variety of solid tumors. It is taken orally and generally well tolerated, with fatigue and dizziness being the most reported side effects.