Some colorectal cancer patients may benefit from a drug approved this week by the Food and Drug Administration (FDA). Larotrectinib, to be sold under the name Vitrakvi, will treat a variety of solid tumors characterized by a unique biomarker, the NTRK-fusion gene.
Neurotrophic receptor tyrosine kinase (NTRK)-fusion genes are rare and are formed exclusively in cancer cells by genetic rearrangements. Biomarker testing can help patients and their medical teams discover the NTRK-fusion gene.
NTRK-fusion genes drive tumor growth. The new drug, larotrectinib, blocks NTRK fusions, making it effective in fighting cancer.
The FDA’s accelerated approval of larotrectinib was based on the long-term successful treatment of 55 adult and pediatric patients with NTRK-fusion-positive tumors in three clinical trials.
This is the second FDA-approved targeted therapy agnostic to a tumor’s tissue of origin. The therapy is a demonstration of precision medicine, the practice of individualizing medical treatment plans due to the presence of a specific biomarker.
The Colorectal Cancer Alliance welcomes this approval that could expand the use of new drugs beyond one disease and expedite market entry. This decision may also promote repurposing current drugs based on their genetic targets and benefit additional groups of patients.
While NTRK-gene fusions are rare among sporadic colorectal cancer patients (1 to 2 percent), this alteration is more common in tumors deficient in mismatch repair, dMMR, and tumors with high levels of microsatellite instability (MSI-H).
Patients who are MSI-H and with metastatic disease, and who do not have a known acquired resistance mutation, should ask their physician about testing for the NTRK-fusion biomarker. Initially, most patients are not offered tests for this biomarker.
Learn more about biomarkers here.