Loxo Oncology Inc.'s cancer drug larotrectinib recorded a shrinkage in tumor size across three clinical trials for patients whose cancers have a specific genetic mutation.
The trials — a phase 1 adult trial, a phase 2 trial called Navigate and phase 1/2 pediatric trial called Scout — evaluated the drug in patients whose tumors harbor tropomyosin receptor kinase, or TRK, gene fusions. The trial comprised 55 patients, ranging from 4 months to 76 years of age, with 17 unique tumor types, including salivary gland, infantile fibrosarcoma, thyroid, colon, lung, melanoma, gastrointestinal stromal tumor and other cancers.
TRK fusions are chromosomal abnormalities that occur when one of the neurotropic tropomyosin receptor kinase, or NTRK, genes becomes abnormally connected to another unrelated gene. This abnormality results in uncontrolled TRK signaling that can lead to cancer.
Larotrectinib is an oral cancer treatment based on genetic traits of the tumor and not the organ where the cancer originated. It is designed to directly target TRK, turning off the signaling pathway that allows TRK fusion cancers to grow.
Based on the central assessment of the trial results, 75% of the patients saw a reduction in their tumor size, while the investigator assessment showed that 80% of patients saw decrease in tumor size.
As of the July 17, 2017 data cutoff, 86% of responding patients remained on treatment or had undergone surgery with curative intent.
No patients discontinued treatment due to drug-related side effects.
The U.S. Food and Drug Administration has granted larotrectinib breakthrough therapy designation that resulted in an expedited review.
In June 2017, the Stamford, Conn.-based drugmaker presented data showing 76% of the patients being treated by larotrectinib showed a reduction in tumor size, resulting in a rise of more than 40% in the company's stock price.
In November 2017, Loxo Oncology and Bayer AG entered into an exclusive global collaboration to develop and commercialize larotrectinib. Loxo Oncology leads the worldwide development and U.S. regulatory activities, while Bayer leads ex-U.S. regulatory activities and worldwide commercial activities. The companies will co-promote the drug in the U.S.
In December 2017, Loxo Oncology initiated the submission of a rolling new drug application to the U.S. Food and Drug Administration for larotrectinib. The rolling submission is expected to be complete in early 2018 and a marketing authorization application submission by Bayer in the EU is expected in 2018.