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NTRK Fusions in Cancer: Detection Strategies and Targeted TRK Inhibitor Therapy

This review covered the biology, detection, and treatment of NTRK fusion-positive cancers, which respond to TRK inhibitors with response rates exceeding 75% regardless of tumour histology. Detection methods including tumour DNA/RNA sequencing and plasma cfDNA profiling were evaluated, making this a key reference for laboratories implementing histology-agnostic biomarker testing strategies.

The original study

NTRK fusion-positive cancers and TRK inhibitor therapy.

Authors
Cocco E, Scaltriti M, Drilon A
Journal
Nature reviews. Clinical oncology
Type
Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Review
PMID
30333516
Read the original study →

Original abstract

NTRK gene fusions involving either NTRK1, NTRK2 or NTRK3 (encoding the neurotrophin receptors TRKA, TRKB and TRKC, respectively) are oncogenic drivers of various adult and paediatric tumour types. These fusions can be detected in the clinic using a variety of methods, including tumour DNA and RNA sequencing and plasma cell-free DNA profiling. The treatment of patients with NTRK fusion-positive cancers with a first-generation TRK inhibitor, such as larotrectinib or entrectinib, is associated with high response rates (>75%), regardless of tumour histology. First-generation TRK inhibitors are well tolerated by most patients, with toxicity profiles characterized by occasional off-tumour, on-target adverse events (attributable to TRK inhibition in non-malignant tissues). Despite durable disease control in many patients, advanced-stage NTRK fusion-positive cancers eventually become refractory to TRK inhibition; resistance can be mediated by the acquisition of NTRK kinase domain mutations. Fortunately, certain resistance mutations can be overcome by second-generation TRK inhibitors, including LOXO-195 and TPX-0005 that are being explored in clinical trials. In this Review, we discuss the biology of NTRK fusions, strategies to target these drivers in the treatment-naive and acquired-resistance disease settings, and the unique safety profile of TRK inhibitors.