The Future of Droplet Digital PCR and Blood-Based Assays: An Interview with Gary Pestano and Hestia Mellert
Posted 26th January 2018 by Kate Barlow
We caught up with Dr. Gary Pestano, VP, Development and Operations, Biodesix, and Dr. Hestia Mellert, Director, Development, Biodesix, at the 5th qPCR and Digital PCR Congress at 4Bio, where we discussed novel applications, single-cell technology, and the future of ddPCR and PCR.
Could you tell us a little bit more about the company?
Gary Pestano: Biodesix is a multi-omics development company, which also commercialises blood-based assays. Two of the platforms we have are droplet digital PCR. We use a Bio-Rad platform, and then mass spectrometry is our other test platform. We have commercial tests in both GeneStrat and VeriStrat, which are PCR and multi, respectively.
What is your current focus at Biodesix?
Gary Pestano: For myself, novel technologies and the ways in which people are approaching them. For example, we just sat through a talk from Adrian Briggs from Juno Therapeutics, on single-cell sequencing for immune transfers. I think there’s a lot of other examples of that kind of thing going on, and the meeting is very useful for bringing those technologies together.
Hestia Mellert: Single-cell technology is definitely something that piqued my interest as well.
Gary Pestano: One of the major focus areas for the company is the development of tests that may be of relevance to immuno-therapies, both on-market and in trials. This includes the use of our multi-omic platforms for discovery, development and commercialisation. Recently, we have provided updates to our multi-variate classifier approach and on our PD-L1 concept in development: “Development and Clinical Validation of Liquid ddPCR Tests for Actionable Somatic Mutations in NSCLC.” The latter is a blood-based test that could be of use for patients with lung cancer who do not have a tissue result available. Developing a liquid biopsy for PD-L1 is a complex development project, but there is a clear clinical need, as an objective measure of PD-L1 status is needed by physicians considering immunotherapies for their lung cancer patients.
Is single-cell technology something that you would like to look into further?
Hestia Mellert: Generally, our company is interested in picking novel technologies and then finding the clinical utility of them, so we can bring them into clinical laboratory. Watching how people in the research setting are starting to develop novel ways of looking, and especially in the oncology space because it’s exciting for bioscience right now, is great. It means we can get an early look at what might be coming next for their clinical use.
What are your thoughts on what’s happening in the ‘oncology space?’
Hestia Mellert: Liquid biopsies are becoming more and more accepted, particularly by community physicians seeking timely diagnostic test results to inform treatment decisions. The number of treatment options, especially in certain disease states, like lung cancer, are multiplying rapidly, and the demand for testing that can help physicians determine which patients are most likely to benefit from treatment is likely to follow.
Is there anything else that you picked out in terms of clinical applications?
Gary Pestano: We’re excited about looking at some of the NGS applications, and I think that’s the other track that we’ll be attending for the most part here. I think there are some applications in there, as well as some clinical experiences being related in the plenary sessions.
Hestia Mellert: One of the things with digital PCR in general, as it tries to compete with Next Generation Sequencing, is being able to look at more targets in one reaction, so it was interesting for me to see someone’s presentation about their multiplex format. Being able to look at additional targets within that technology is really beneficial, so that’s another interesting topic.
Gary Pestano: The ways in which new technologies are positioning themselves within niche places that are relevant for the clinic, whether it’s fast turnaround time or cost. I think that’s also something that we’re very interested in having.
Hestia Mellert: Could you elaborate on the competition between NGS and Digital PCR?
They both have their place in diagnostic testing. NGS is an ideal tool for physicians treating patients with advanced cancer who have failed first- and second-line treatments ie. in the discovery of treatment options; in this situation, NGS results are useful to help narrow down clinical trial options. However, for an easily accessible, fast and accurate method to look at a finite number of targets (such as those in the treatment guidelines), we think that digital PCR is a more practical choice to support treatment decisions at diagnosis. Digital PCR offers precise and specific measurement and in our experience can result in tests in as little as 48 to 72 hours. Further, digital PCR is ideal for testing from plasma, allowing testing when a tissue result is delayed or not possible.
Are there any new future projects for your company or any new applications you’re taking on recently?
Gary Pestano: The poster we had focused on for what we’re doing with PD-L1 expression in blood. In the US, that’s one of our most challenging assays to beat and for nucleic acid detection that we’re looking at. We also saw work presented from Biogazelle today on copy number and expression in blood. That’s very interesting, and that’s another company that we’ll be probably be looking into and talking about. Then, of course, we continue to look at immunotherapy applications as well, which we are looking forward to.
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