Tumors of varied types of genetically defined cancer were significantly reduced by the drug LOXO-101, according to phase 1 study results presented at the American Association for Cancer Research 2016 Annual Meeting.1

The study followed patients with proteins called tropomyosin receptor kinase fusions (TRKs).

“We saw efficacy with significant tumor regression in all 6 TRK fusion patients enrolled in the study,” said David Hong, MD, associate professor of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center. “We were surprised by the fact that the study demonstrated efficacy in every one of the TRK fusion-positive patients.”

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The study enrolled 43 patients, 6 of whom had TRK gene fusions in tumors representing cancers such as sarcoma, thyroid, salivary gland, gastrointestinal, and non-small cell lung. Among the 6 patients with TRK gene fusions, 5 had partial responses to LOXO-101 and the sixth patient had a 17% tumor regression. All 6 patients remain on the study, the longest for more than 1.5 years.

“We are currently enrolling all solid tumor types with TRK fusions for a phase II trial,” said Hong. “Over time, we anticipate that the list of tumor types will continue to grow. In published literature, TRK fusions have been found in nearly every tumor type. The phase II study is important not only for generating additional data about LOXO-101 in patients with TRK fusion cancer, but we anticipate it will further broaden the range of tumor types that we’ve tested thus far.”

The phase 1 study found LOXO-101 to be well tolerated, with fatigue, constipation, and dizziness being the most common side effects. The planned phase 2 trial will only include patients who test positive for the TRK gene fusions and will use a dosage of 100 mg twice daily.


1. Hong DS, Farago AF, Brose MS, et al. Clinical safety and activity from a phase I study of LOXO-101, a selective TRKA/B/C inhibitor, in solid-tumor patients with NTRK gene fusions. Presentation at: American Association for Cancer Research 2016 Annual Meeting; April 16-20, 2016; New Orleans, LA. Abstract CT0008.