Imperial College London and its spinout company DNA Electronics have developed the prototype for a handheld device that physicians can use to determine on the spot which patients are genetically predisposed to have an adverse reaction to certain drugs.
The so-called SNP Dr. is being developed under a £1.2 million ($1.7 million) project, involving Imperial College London, DNA Electronics, and Pfizer. Under the terms of the collaboration, which is partially funded by the UK government, Imperial College and DNA Electronics will run clinical trials and develop the device. For its part, Pfizer will provide the clinical samples for the trials together with "access to its distribution network in the pharmaceutical sector and feedback as a potential end user of the product," according to an ICL statement issued last week.
Because the project is at such an early stage, many of the details surrounding it are confidential, Leila Shepherd, DNA Electronics' chief technology officer, told Pharmacogenomics Reporter this week.
According to DNA Electronics' website, SNP Dr. is based on the firm's real-time Genalysis platform, which tests for target nucleic-acid sequences. The device relies on microfluidics, disposable lab-on-chip cartridges with biochemical reagents, and low-power silicon biosensors to detect genetic mutations.
It was not immediately clear which specific SNPs the device would look for, or for which diseases SNP Dr. would gauge pateints' risk for adverse events. Imperial College describes it as "a test to identify people likely to react badly to prescribed medication such as antidepressants or drugs to lower cholesterol," and as a device that "could enable doctors to tailor dosages and drugs" to individual patients.
On its website, DNA Electronics highlights the compact size and portability of the SNP Dr. to emphasize it can be used eventually for infectious disease screening and personalized medicine in the clinic, in hospitals, and at home.
"Genalysis cartridges can be tailored to any sequence of interest, human or microbial, making this a customizable platform technology amenable to a wide variety of applications and markets," DNA Electronics states on its website.
According to a statement by Shepherd, the introduction of the SNP Dr. into a general practitioners' office could lead to the development of new genetically targeted drugs.
Although big pharma often characterizes pharmacogenomics as an emerging science not ready for prime time, Pfizer, the world's largest drug maker by revenue, is investing in developing companion diagnostics.
For instance, Pfizer helped commercialize Monogram Biosciences' Trofile assay, which was designed to determine the tropism status of patients prior to administering Pfizer's HIV drug Selzentry [see PGx Reporter 12-06-2006].
In another deal with Genomic Health, Pfizer is developing a genomic test to gauge the risk of post-operative kidney cancer recurrence based on Genomic Health's Oncotype DX platform. The test may be a companion diagnostic to Pfizer's Sutent, a kinase inhibitor indicated for advanced renal-cell carcinoma [see PGx Reporter 01-09-2008].
Although Pfizer is providing the clinical samples meant to help DNA Electronics develop the SNP Dr. device, and could potentially be an end user of the product, it is not immediately clear whether SNP Dr. would correspond with drugs currently marketed or being developed by the pharma giant.
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Given the high cost of treatment, limited efficacy, and severity of adverse reactions associated current cancer treatments, oncology may be one market in which SNP Dr. might be immediately useful.
"At the moment, some cancer drugs are deemed uneconomical because they only work for a certain subset of patients," DNA Electronics' Shepherd said in a statement. "If doctors had a method of screening patients to see whether these drugs work, then suddenly these therapies would be more cost effective to use."
In the oncology market, there are several clinical diagnostic tests for detecting which breast cancer patients would benefit from treatment with Genentech's Herceptin by gauging HER2 and HER2 homodimer levels [see PGx Reporter 05-21-2008].
In addition, diagnostic tests are available to interrogate KRAS mutations in colorectal cancer patients prior to treatment with anti-EGFR monoclonal antibodies such as Bristol-Myers Squibb's Erbitux and Amgen's Vectibix [see PGx Reporter 02-04-2009].
SNP Dr. could also be potentially useful in reducing adverse reactions to highly variable drugs, such as the anticoagulant warfarin. Approximately 2 million people are initiated on warfarin therapy each year to prevent blood clots, heart attacks, and stroke. According to the US Food and Drug Administration's adverse events reporting database, complications from warfarin are the second-most common reason for emergency room visits, behind adverse reactions from insulin.
One concern with currently available genetic warfarin-dosing tests is the amount of time it sometimes takes for laboratories to analyze patient samples and return the results to doctors [see PGx Reporter 05-07-2008]. An "on-the-spot" device like SNP Dr. could very well eliminate such delays, which could lead to costly adverse reactions
"In some applications, a real-time answer at the point of care would save time, money and lives," DNA Electronics states on its website.
DNA Electronics did not say whether it plans to clear SNP Dr. through the FDA.