What is larotinib/larlotinib?

Larotrectinib is an oral, selective tropomyosin receptor kinase (TRK) inhibitor indicated for the treatment of solid tumors containing NTRK fusion proteins. Research shows that the NTRK gene can abnormally fuse with other genes to produce TRK fusion proteins, which can lead to the development of solid tumors in various parts of the body. Examples of tumor types with NTRK fusions that currently respond to larotrectinib include soft tissue sarcoma, salivary gland cancer, infantile fibrosarcoma, thyroid cancer, and lung cancer.

The efficacy of larotrectinib was studied in three clinical trials that included55 pediatric and adult patients with solid tumors harboring identified NTRK gene fusions. The overall effectiveness of larotrectinib against different types of solid tumors was 75%. The responses were durable, with 73% lasting at least six months and 39% lasting a year or more. Larotrectinib received accelerated approval, which allows the U.S. Food and Drug Administration (FDA) to approve drugs for serious diseases that address unmet medical needs using clinical trial data that are thought to predict clinical benefit to patients. Further clinical trials are needed to confirm the clinical benefit of larotrectinib.

Larotrectinib is available in two forms: capsules (25mg, 100mg) and oral solutions (20mg/mL), which can be taken orally twice daily. In clinical trials, common side effects (≥20%) reported in patients receiving larotrectinib included fatigue, nausea, cough, constipation, diarrhea, dizziness, vomiting, and increased blood levels of hepatic aspartate aminotransferase (AST) and alanine aminotransferase (ALT).