FDA Approval for Drug that Targets Mutation in Multiple Cancers

Dr. Laetsch and one of his successfully-treated patients, Briana Ayala (Courtesy of: UT Southwestern).

The FDA approved a treatment that targets a specific fused gene that is common in several types cancer cells, shifting the treatment from focusing on a certain type of cancer or organ to fighting a common mutation in a wide range of tumors. Dr. Theodore Laetsch of UT Southwestern and Children’s Health is leading the work with this new form of precision medicine.

The drug, called Larotrectinib, was found to be effective in 93 percent of patients tested at UT Southwestern’s Simmons Cancer Center. The mutation occurs when a TRK gene attaches to another gene, where the gene turns on and causes the cells to grow uncontrollably. This mutation occurs in many types of cancer, especially rare pediatric cancers. But the treatment blocks only the gene and not productive cell growth.

The Washington Post reports that even though the drug is expensive at $32,800 for a 30-day supply for adults and $11,000 for children, the manufacturer Loxo Oncology Inc. and its partner Bayer think most insurers will cover the drug. The companies say out of pocket costs should be $20 or less per patient. Bayer is offering payment assistance and a money back guarantee if the drug doesn’t provide a benefit in the first three months.

But the trial results have been overwhelmingly positive.

“Every patient with a TRK fusion-positive solid tumor treated on this study had their tumor shrink. The nearly universal response rate seen with larotrectinib is unprecedented,” Dr. Laetsch said via release.

Among the successful patients was Briana Ayala of El Paso, who had a tumor wrapped around her aorta. The cancer continued to grow after surgery was performed at Children’s Health in Dallas, but she enrolled in the trial for larotrectinib because her cancer had TKR fusion. After a few weeks, her abdomen’s swelling went down and the tumors shrunk significantly. It has been two years and Briana is doing well and is back in school.

“These are the kind of amazing responses we’ve seen with larotrectinib,” said Dr. Laetsch via release, “and this is why I’m so excited about it.”