TRK Inhibitors: A Tumor Agnostic Targeted Therapy - Episode 12
David S. Hong, MD:I think you have to be wise. Obviously, there are not unlimited resources in this country at this time. I think of mistesting. If I was a community doctor, when would I order this? Well, if you’re not already ordering next-generation sequencing [NGS] assays already for your nonsmall cell lung cancer patients who, as I shared, tend to be younger and who don’t fit your typical profile of a patientfor example, a nonsmoker—it may be worth ordering that drug, or for papillary thyroid cancer patients who are iodine-refractory who have no other alterations or sarcoma patients. Not all of the vendors carry fusion testing. For example, Oncomine, I think there’s a separate panel. FoundationOne, for example, is a DNA NGS panel that coversNTRK1/2andNTRK3ETV6, but you really have to order Foundation Heme which is an RNA sequence panel to cover all of the different possible partners forNTRK3.
Shubham Pant, MD:So what you are saying is that for theNTRK3, you need to order more, but essentially in the one test. So you need to know what test you are looking for. Because the other thing is there are so many vendors out there now. And so even as an oncologist practicing in the community, you’ve got to look at and ask, “Am I getting all the genes that can be picked up in this patient?” Is that accurate?
David S. Hong, MD:Yes, yes. I can’t really speak to this data wise, but at least the vast majority of patients who we see that come from the outside have FoundationOne testing. And, as I shared, FoundationOne testing does cover 1, 2, andETV6 NTRK3fusion partner, which should cover a fair number of NTRK patients. But, to really be comprehensive, you’d really have to orderI think there’s a way to order—Foundation Heme for a solid tumor patient. My understanding is that FoundationOne is considering, since this new approval, incorporating these furtherNTRKfusion patients. The other vendors include Caris, which has, can incorporate the Archer fusion assay, which covers everything. Those are probably the 2 biggest vendors out there. There are other vendors like we use in our institution. We use an Oncomine platform with a fusion assay that has been incorporated.
Shubham Pant, MD:So, essentially, what you’re saying is there are different assays out there, there are different products out there, there are different companies out there that are producing these. But as an oncologist, you just have to make sure you are getting all the genes that you’re looking for.
David S. Hong, MD:Correct.
Shubham Pant, MD:Especially you have to be aware of what it is,NTRK1,2,3. You’ve got to be aware of all the fusions, so that you can ask that question, saying, “Hey, are you testing forNTRK1,2, and3, all 3 of them?”
David S. Hong, MD:Right, exactly. There’s a number, and I’m sure there are, as we speak, additional vendors who are coming onboard. But I think it’s important to just ask if there is a fusion assay if you really want to test forNTRKand to ask specifically what genes are being tested.
Transcript edited for clarity.