The Food and Drug Administration, the U.S. agency responsible for overseeing and approving new medical treatments, designated LOXO-101, a selective inhibitor of tropomyosin receptor kinase, as “Breakthrough Therapy”. This means that the drug has shown significant health advantages to be fast-tracked and prioritized in development.
The clinical trials involved 41 patients with several types of cancer (including sarcoma, lung cancer, breast cancer, gastrointestinal stromal tumor, thyroid cancer) that were unresponsive to other forms of therapy. One or two dosed, ranging from 50mg to 150 mg, of LOXO-101 were administered orally for 28-day cycles.
Larotrectinib, or LOXO-101, revealed positive responses in the majority of the test subjects, and up to 21% tumor regression in some of the cases. The gene fusions were noticed with NTRK1 or NTRK3, but patients that had no NTRK, displayed not responses.
The most common side effects reported were fatigue (grade 1 or 2) in about 30 percent of the patients, followed by dizziness and nausea in nearly 20 percent of cases. Considerably fewer and lighter than what most other treatment courses induce.
Josh Bilenker, M.D and chief executive officer of Loxo Oncology mentioned in a press release that “data presented to date from the ongoing adult and pediatric studies of LOXO-101 have demonstrated durable anti-tumor activity across TRK fusion cancers, further validating LOXO-101’s potential to address the unmet medical need among patients with these genetically defined cancers”.
Plans for further research, including one relating to TRK fusions, are underway and look very promising. Additional clinical sites are also expected to be opened.