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Precision Medicine: New Diagnostic Tool for Cancer Treatment

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Published on March 11, 2013

Transcript | Precision Medicine: New Diagnostic Tool for Cancer Treatment

Please remember the opinions expressed on Patient Power are not necessarily the views of Seattle Cancer Care Alliance, its medical staff or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

Andrew Schorr:

Hello and welcome to Patient Power, sponsored by the Seattle Cancer Care Alliance.  I’m Andrew Schorr. 

We’re in the age of precision medicine.  What does that mean?  Well, for you, if you’re the cancer patient or for a friend or family member, you want the most precise treatment, hit the cancer cells, and, if you can, limit side effects by not hitting healthy tissue.  And, so, something called next generation sequencing comes into play, understanding what the specific genetic situation of your cancer is. 

And the University of Washington and the Seattle Cancer Care Alliance (SCCA) is leading the way in this, and our guest today, Dr. Colin Pritchard, who is Associate Director of the Clinical Molecular Genetics Laboratory at the University of Washington (UW), is a true expert in this.  Dr. Pritchard, thank you so much for being with us. 

Dr. Pritchard:

Thank you for having me. 

Andrew Schorr:

Dr. Pritchard, you’ve led the way in developing something called UW-OncoPlex.  What is that? 

Dr. Pritchard:

UW-OncoPlex is a multiplex gene panel.  It’s a clinical diagnostic assay for cancer patients, that tests tumor tissue and looks for mutations in different genes that we would call actionable; that is, if there is a mutation in that gene in the patient’s tumor tissue there may be a drug that’s associated with response in that particular tumor subset.  It’s new technology, in that for the first time we’re able to simultaneously look at hundreds of genes and literally tens of thousands of possible mutations in one diagnostic test. 

It’s really exciting, because we can then kind of find that needle in a haystack.  So, even if a mutation is, say, only one in a thousand chance—let’s say, you’ve got lung cancer and you have a one in a thousand chance of having a certain mutation, well, if we can look at lots and lots of different genes we’ll be able to find more of those targets that may be associated with response or even lack of responses for drugs, which helps the oncologist make treatment decisions. 

Andrew Schorr:

Dr. Pritchard, let’s talk about that.  As I said, everybody wants the right cancer medicine for them, with the fewest side effects.  Is the idea here, that you can take a little sample of cancer tissue, let’s say, if they have a solid tumor maybe that was removed during surgery or a biopsy, or if they have a blood cancer, a blood test result, that goes to your special lab, goes through this next-generation sequencing, and then you can help the patient and their doctor know what approach might be right for them, and you can do it fairly expeditiously.  Did I get it right? 

Dr. Pritchard:

Yeah, that’s exactly the idea.  It’s both for blood cancers and for solid tumors, and usually the test is done on, if it’s a solid tumor, tissue that’s already been taken as part of a biopsy or maybe as a tumor resection that’s already banked, or if it’s a blood cancer from a blood sample or a marrow sample, and that’s exactly right.  It’s just sort of a test for mutations that will guide therapy, and as expeditiously as possible, of course. 

Andrew Schorr:

And the idea is to get the right medicine, which will hopefully have fewer side effects, right? 

Dr. Pritchard:

Yeah, that’s absolutely right. It can also be useful to know that you are not going to respond to a drug that may have been the first choice of your oncologist, because, obviously, every drug has some side effects.  If you know that you’re very unlikely to respond to a drug, that’s also very helpful, in that you won’t have those side effects. 

And then the converse of that, the more exciting thing, is that you may have mutations in your tumor that suggest you will respond well to certain targeted therapy.  And in general, targeted therapies, as opposed to traditional chemotherapies—in general, not always—do have a better or lower side effect profile. 

Andrew Schorr:

Dr. Pritchard, with your special next-generation sequencing, does it sometimes come up with a result that’s unexpected? 

Dr. Pritchard:

Yeah.  We’ve seen that there are targets that are unexpected, that strongly suggest a drug that may be an FDA approved drug for a different kind of cancer, that then may be appropriate for the cancer that’s being tested, that’s something that never would have, in the oncologist’s wildest dreams, been considered as an appropriate therapy.  And, we’re already seeing early evidence that that approach is associated with patient benefit, so, that’s very exciting in that it’s expanding the repertoire of possible drugs for a certain cancer type. 

Andrew Schorr:

Now, what cancer types are you currently using this testing for?

Dr. Pritchard:

We’ve been offering this test since August of 2012.  We’ve done about 150 cases now, and we’ve been mostly looking at lung cancer and colon cancer, I think, as the two largest areas.  We’ve also, in terms of just absolute numbers, we’re looking at melanoma, acute myeloid leukemia.  We’ve done esophageal cancer cases, gastric cancers, pancreatic cancers, just to name a few.  So, we’ve done quite a few different kinds of cancers, but for the time being, lung cancer and colon cancer, and to some extent, acute myeloid leukemia, have been the three, sort of, top numbers, in terms of just numerically, the numbers of cancers that we’ve tested. 

And that’s not an accident.  The reason for that is that, especially in lung cancer, there are a lot of different targeted therapies out there, and there’s a lot known about a lot of different genes that target those therapies, so it’s no accident that oncologists are using this test in patients with lung cancer, in particular.  And the same could be said for colon cancer.  There are more targeted therapies emerging there. 

But, I should emphasize that these targeted therapies are not limited to just colon cancer, lung cancer, or acute myeloid leukemia.  They’re being developed for pretty much every cancer out there, to varying degrees.  So, I think that this kind of testing will have utility in a very wide of cancers, and we’ve already done a limited number of cases in probably a dozen or more different cancer types. 

Andrew Schorr:

Dr. Pritchard, you’re a modest man.  I want to let you toot your own horn for a minute, you and your team at the University of Washington.  I know it’s been recognized nationally, and internationally, your leadership in UW-OncoPlex.  Tell us about how unique it is, what you’re doing now. 

Dr. Pritchard:

Well, I mean, this is certainly an area that a lot of major academic medical centers are getting into. I think that we are, the UW and SCCA really are, leading the way in terms of what I would call true clinical.  So, there are certainly more comprehensive genomic testing strategies out there for cancer patients, but they’re primarily limited to research protocols, whereas this is something that an oncologist can just order.  You see your oncologist in clinic, fills out a requisition, and order a test. 

In terms of true clinical testing, I think this is really leading the country, and not just in terms of the sort of comprehensiveness of the number of genes that we’re testing, but, I think, also in the analysis methods.  We’ve put a lot of work into what we call the bioinformatics, which is—so you do sequencing of the tumor and you look for mutations, but you need complex methods to detect certain kinds of mutations, and we’ve focused a lot of our efforts on that, and I think we—not to toot my own horn too much—but I think we really are leading the country in terms of the bioinformatics and the analysis approaches that we’re taking to be able to detect things like, for example, ALK rearrangements in lung cancer by sequencing.  That’s something that not very many places are doing as a true clinical assay, because it’s challenging in terms of the analysis methods.  So, that’s just one example.  I think that we, the UW and SCCA, really are at the leading edge of precision medicine with UW-OncoPlex. 

Andrew Schorr:

Dr. Colin Pritchard, thank you so much for being with us today and all you do at the University of Washington and Seattle Cancer Care Alliance. 

Dr. Pritchard:

Thank you, Andrew.  I appreciate it. 

Andrew Schorr:

There you have it, the latest in testing for cancer patients and their specific cancer genetics, so, they can get actionable information to get the treatment that’s right for them. 

Thank you for joining us.  I’m Andrew Schorr.  Remember, knowledge can be the best medicine of all.

Please remember the opinions expressed on Patient Power are not necessarily the views of Seattle Cancer Care Alliance, its medical staff or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

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