Anna F. Farago, MD, PhD
Loxo Oncology completed a rolling new drug application (NDA) to the FDA in March 2018 for larotrectinib (LOXO-101), a pan-TRK inhibitor codeveloped by Bayer. If approved, larotrectinib would be available as a treatment for both adult and pediatric patients with locally advanced or metastatic solid tumors harboring an NTRK
in patients with locally advanced solid tumors.
OncLive: Can you provide some background on larotrectinib?
: There have been 3 trials with this drug. There was a phase I study with adult patients, a phase I/II trial for pediatric patients, and a phase II study for adolescents and adults. Those data were put together for a presentation at the 2017 ASCO Annual Meeting, and then in a recent publication in the New England Journal of Medicine
. We participated in the phase I adult study and in the phase II adolescent and adult study.
Biologically, from what we know about this drug being an inhibitor of TRK signaling and the configuration of these fusions that lead to constitutive activation of the TRK kinase domain, it makes sense to me that a drug that is an inhibitor of kinase signaling would be active in cancers in which that TRK signaling is acting as an oncogenic driver.
How would an FDA approval of larotrectinib impact the oncology field?
In some cancer types, TRK
fusions are very rare. I am primarily a thoracic oncologist and, in lung cancer, these fusions occur at a frequency of well under 1%. In less common cancer types, they are more common. For example, these are fusions that are commonly seen in pediatric fibrosarcoma. The total number of patients who may benefit is slightly difficult to predict at this point, but for patients whose cancer has a TRK
fusion, these drugs can be tremendously effective.
... to read the full story