Larotrectinib, a tropomyosin receptor kinase (TRK) inhibitor in clinical development by Loxo Oncology, has demonstrated consistent and durable antitumor activity in TRK fusion cancers across a wide range of patient ages and tumor types and was well tolerated by patients, according to data from three clinical trials presented in June 2017 at the annual meeting of the American Society of Clinical Oncology in Chicago.
David Hyman, MD, chief of the Early Drug Development Service at Memorial Sloan Kettering Cancer Center in New York City and global principal investigator of the NAVIGATE trial testing the experimental drug, presented interim analyses from the ongoing trials. Fifty-five patients with TRK fusion cancers, ranging in age from four months to 76 years (43 adult and 12 pediatric patients), were enrolled in the trials. In total, 17 discrete tumor types were treated. The overall response rate of the patients evaluated thus far was 76%, and the longest responder still remains on the treatment after 25 months. At the time the data were analyzed, 93% of the responding patients remained on treatment or underwent surgery with curative intent, and because of this, the median duration of response could not yet be determined.
“TRK fusion-positive cancer may be among the first cancer types that is more appropriate to define on the basis of a shared genetic mutation than by the organ in which it arises,” said Dr. Hyman. “No other novel targeted therapy has demonstrated consistent benefit across all tumor types that test positive for a specific mutation.”
Additionally, he said this could be the first treatment developed and approved simultaneously for adult and pediatric patients.
The researchers will continue to follow the trial participants until a median duration is established. The most common treatment-related adverse side effects included fatigue, mild dizziness, and nausea.