TRK-Fusion Differentiated Thyroid Cancer
Steven Waguespack, MD, of the University of Texas MD Anderson Cancer Center, Houston, shared updated efficacy and safety data from three phase 1/2 pooled clinical trials of the tropomyosin kinase receptor (TRK) inhibitor larotrectinib in thyroid cancer. These data updated results initially published in 2022.
“Larotrectinib continues to demonstrate rapid and durable responses, extended survival, and offers a favorable safety profile in patients with TRK fusion differentiated thyroid cancer, with limited activity in anaplastic thyroid cancer,” Waguespack said.
“Additionally, in a subset of patients, we identified some acquired on-target NTRK mutations and off-target GNAS and TP53 mutations that may give further insight into mechanisms of resistance.”
The primary endpoint was the investigator-assessed objective response rate (ORR); at 48 months, the ORR was 79% by independent review. The median PFS in patients with TRK fusion differentiated thyroid cancer was 44 months, while the median duration of response was 41 months. The 4-year overall survival rate was 86%.
Waguespack closed with a cautionary note to colleagues: “While circulating tumor DNA next-generation sequencing (NGS) analysis can be used to test for NTRK gene fusions, negative results should be followed up with tissue-based NGS,” he said.
Brito Campana and Goldberg disclosed no relevant financial relationships. Hadoux reported receiving honoraria for speaker engagements, advisory roles, or funding for CME from Eli Lilly, AAA, IPSEN, Roche, Pharma Mar, and EISAI, and research grants from Novartis, Sanofi, and Eli Lilly.
A version of this article appeared on Medscape.com.