FDA approval advances ‘precision medicine’

WASHINGTON — The Food and Drug Administration approved a drug Monday for a wide range of cancers based on a shared mutation rather than the tumors’ locations.

It’s an advance for the sometimes-controversial field of “precision medicine.”

The medication, called Vitrakvi, is the second treatment to receive FDA clearance based on a common biomarker found in an array of cancers. The drug, also called larotrectinib, was approved simultaneously for both adults and children. Typically, oncology drugs are considered much later for children.

Last year, the agency, for the first time, approved an immunotherapy drug for tumors with a specific genetic signature, regardless of where they originated in the body. But that treatment already had been cleared for several cancers, including advanced melanoma.

The drug approved Monday is for patients with advanced solid tumors containing what’s called an NTRK gene fusion, a hybrid of two genes that can promote uncontrolled cell growth. Cancers of the thyroid, lung and head and neck, among others, can be caused by the defect. The drug is for patients whose cancer has spread or who would experience severe complications by undergoing surgery and have no satisfactory alternatives.

The drug’s manufacturer, Loxo Oncology, Inc., now faces a huge challenge: finding patients who might benefit. Only an estimated 2,000 to 3,000 people a year in the United States develop NTRK-related cancers. The mutation occurs in less than 1 percent of most solid tumor types, but it is common in malignancies such as adult salivary cancer and infantile fibrosarcoma.