TRK Inhibitor Effective in TRK-Fusion Advanced Thyroid Cancer

The TRK inhibitor larotrectinib is well tolerated and had antitumor activity in patients with advanced TRK-fusion nonmedullary thyroid cancer (TC), according to an analysis presented at the 88th Annual Meeting of the American Thyroid Association in Washington, D.C.¹

NTRK fusion genes are oncogenic drivers and have been reported in TC. Larotrectinib is a selective TRK inhibitor that showed an objective response rate of 75% in a small study of patients with cancers harboring TRK fusions. The purpose of this analysis was to summarize the efficacy and safety of larotrectinib in patients with TRK-fusion TC.

The study treated 7 patients with previously treated TRK-fusion TC with the dose equivalent of 100 mg of larotrectinib twice daily on a continuous 28-day schedule. All patients had undergone thyroidectomy. Of the 7 patients, 5 had received a median of 3 prior lines of systemic therapy and 3 had received treatment with iodine-131. Measurable disease was present in 5 patients.

Larotrectinib treatment resulted in 1 complete response and 4 partial responses with a median time to first response of 1.8 months. There were 4 ongoing responses and the duration of response was 1.9 to 18.8 months. All patients remained on therapy at data cutoff.

Larotrectinib was well tolerated; most treatment-related adverse events were grade 1.

These data suggest that larotrectinib is effective against TRK-fusion TC. The authors concluded that “these results strongly support the inclusion of NTRK gene fusions as part of routine molecular testing for patients with advanced TC.”

Read more of Cancer Therapy Advisor‘s coverage of the ATA 2018 meeting by visiting the conference page.

Reference

1. Brose MS, Albert CM, Waguespack SG, et al. Activity of larotrectinib in patients with advanced TRK fusion thyroid cancer. Presented at: the 88th Annual Meeting of the American Thyroid Association; Washington, D.C.: October 3-7, 2018. Abstract clinical oral 10.