Larotrectinib Efficacy Highlights Importance of Genomic Testing in Thyroid Cancer

Marcia Brose, MD, PhD, director of the Center for Rare Cancers and Personalized Therapy, director of the Thyroid Cancer Therapeutics Program, associate professor of Otorhinolaryngology: Head and Neck Surgery at the Hospital of the University of Pennsylvania, and associate professor of Medicine at Penn Medicine, discusses how the thyroid cancer treatment landscape will be impacted by the positive findings regarding larotrectinib (Vitrakvi) in the presence of a TRK fusion.

Targeted therapies have been successful as treatment of patients with thyroid cancer, and there have been 2 particular agents available for the last 4 or 5 years now, Brose says. These include sorafenib (Nexavar) and lenvatinib (Lenvima), which are both approved, while a third drug, cabozantinib (Cabometyx) is under evaluation in clinical trials for FDA approval for differentiated thyroid cancer.

TRK fusions appear most commonly in differentiated thyroid cancer, and they don’t tend to be in regular thyroid cancers, Brose notes. However, while these agents are very well tolerated and can be administered for many years in patients, they do come with side effects. Larotrectinib is a striking alternative because it seems to be even less toxic, which means physicians are obligated to get genetic testing done on patients with thyroid cancer prior to starting systemic therapy.

Larotrectinib would be a less toxic alternative as treatment of patients with thyroid cancer with the presence of a TRK fusion compared with the FDA-approved treatments that are currently available.

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