Larotrectinib response best with NTRK fusion mutations
medwireNews: Solid tumor patients with NTRK fusion mutations experience “robust and durable responses” to treatment with larotrectinib, but those with other types of NTRK alterations derive “limited benefit” from the selective TRK inhibitor, investigators say.
David Hong, from The University of Texas MD Anderson Cancer Center in Houston, USA, and team collated data from three clinical trials of adult, adolescent, and pediatric patients undergoing treatment for a broad range of tumors including soft tissue sarcoma, and cancers of the thyroid, salivary gland, lung, colon, and breast.
Speaking at the 2020 AACR Virtual Annual Meeting I, Hong reported that 79% of the 159 patients with a NTRK fusion mutation achieved an objective response to larotrectinib and 12% had stable disease. This compared with rates of 1% and 23%, respectively, among the 73 patients with NTRK point mutations, amplifications, and other non-fusion alterations.
NTRK fusion patients had a better prognosis than their non-fusion counterparts in terms of both overall survival (median 44.4 vs 10.7 months) and progression-free survival (median 28.3 vs 1.8 months).
Noting that adverse events associated with larotrectinib treatment were mainly grade 1 or 2 in severity, Hong concluded that the findings “strongly support the clinical importance of testing for NTRK gene fusions in order to identify patients who would benefit from larotrectinib treatment.”
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