Loxo Oncology  announced in a press release that the FDA has granted breakthrough therapy designation to LOXO-101 for the treatment of unresectable or metastatic solid tumors with neurotrophic tyrosine receptor kinase gene fusions.

This designation applies to the use of LOXO-101 for adults and children who require systemic therapy and who either progressed after prior treatment or for whom no viable alternative treatment exists.

LOXO-101 is a selective inhibitor of tropomyosin receptor kinase that has demonstrated clinical activity in patients with solid tumors with neurotrophic receptor kinase (NTRK) gene fusions. The results of the study were presented at the American Association for Cancer Research annual meeting in April.

The study included 41 patients with tumors that were refractory to other available therapies. Patients in the study received LOXO-101 orally once or twice daily for continuous 28-day cycles.

Seven of the patients had gene fusions involving NTRK1 or NTRK3. Tumor types in this subset included gastrointestinal stromal tumor, non-small cell lung cancer, sarcoma, papillary thyroid cancer or mammary analog secretory carcinoma of the salivary glands.

At the point of data cutoff, six of these seven patients were evaluable, and all six demonstrated clinical response. Five had confirmed partial responses as defined by RECIST criteria. Researchers reported 21% tumor regression in the sixth patient.

A phase 2 basket trial is underway to evaluate LOXO-101 in adults with cancer whose tumors have TRK fusions.

“We’re pleased to have been granted breakthrough therapy designation for LOXO-101 and look forward to working more closely with the FDA to bring this therapy to patients with TRK fusion cancers,” Josh Bilenker, MD, CEO of Loxo Oncology stated in the press release. “Data presented 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.”

For more information, see the LRG’s previous article.