It's exciting to have an approval by the FDA for a targeted therapy in a tumor-agnostic manner. Also, this approval doesn't just impact lung cancer, it impacts all solid tumors because we see these fusions across solid tumors. They are uncommon events in most cancer types. In lung cancer the frequency is about 0.2%; that's not a lot of patients. Proportionally, however, there are a lot of patients with lung cancer as a general population. Therefore, numerically there are a fair number of people out there who could potentially benefit from this drug in the lung cancer community.
Looking at other cancer types, there's a variable incidence of NTRK
fusions. They can be quite common in some rare cancer types, such as infantile fibrosarcoma or mammary analogue secretory carcinoma. However, because they can occur in any cancer type, we need to be looking for NTRK gene fusions, regardless of the cancer tissue of origin. And, if these fusions are identified, then larotrectinib represents an exciting treatment option for patients.What other agents are showing promise for targeting NTRK fusions?
In lung cancer specifically, we're already routinely screening patients for gene alterations in EGFR, ALK, and ROS1. We should be [testing for] RET and making the case for BRAF, NRG1, and others. Adding NRTK to a gene fusion panel shouldn't be too much of a burden for people. We should be asking our molecular pathologists or our commercial vendors to be adding NTRK
to their panels if it's not already included. It's not practical to screen for NTRK
fusions only in this population, because those are such rare events. But, it is practical to screen for all of these events simultaneously using a multi-gene next-generation sequencing–based assay.What should oncologists take away from this presentation on the activity of larotrectinib in TRK fusion lung cancer?
In lung cancer, there are now a growing number of somatic alterations that are potentially treatable with highly active targeted therapies. These alterations include EGFR
, and BRAF
. All patients with advanced or metastatic NSCLC should undergo testing with broad multi-flexed testing to look at all of these mutations simultaneously at the time of diagnosis so that we can identify these patients early and direct them to the appropriate targeted therapy.<<< 2019 World Conference on Lung Cancer