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With Gains in Platform Performance, Thermal Gradient Poised to Expand Beyond HIV Viral Load Assay


By Molika Ashford

MDx startup Thermal Gradient said this week that achievements in the performance and cost of its disposable PCR cartridge technology and success in its HIV assay development project have spurred the company to begin seeking out private investment as well as additional molecular diagnostics partnerships.

The company earlier this month announced improvements in the sensitivity of its disposable test cartridges for PCR assays and claimed advances in production yields and cost reduction.

President and CEO Joel Grover told PCR Insider this week that Thermal Gradient has also had success in its effort to integrate sample preparation into the HIV viral load assay it has been developing with researchers at the University of Massachusetts Medical School under a grant from the National Institute of Allergy and Infectious Diseases.

Grover could not provide details on the results of experiments with a full sample-to-answer system, but explained that the achievements have been robust enough that Thermal Gradient feels it is time to seek out new private investment and to look for partners to develop additional MDx assays beyond the HIV viral load test.

"Right now, we're still talking about the PCR but there is good news we're going to be putting out there on the sample preparation side as well" in coming weeks, he said.

Thermal Gradient's core technology is based on a concept known as continuous flow PCR, in which a sample and PCR reaction components flow through a lab-on-a-chip device with different temperature zones to achieve rapid amplification. The company's system involves a flow path folded into a layered structure that doesn't require valves, pumps, or other moving components, thereby reducing the complexity and cost of the technique.

As of 2011, Thermal Gradient cited performance of 8.5 to 9 logs of amplification (greater than 300 million times) in approximately eight minutes for its PCR technology (PCR Insider 2/10/2011).

In a recent statement it amended that, saying "eleven or more logs of amplification are going to be routinely possible in less than ten minutes" with the detection of PCR products in real time possible "at one nanomolar concentration."

The company also said that it is ready to tailor end-point PCR devices for customers in molecular diagnostics and molecular biology and will be ready "very soon" to produce custom real-time versions. Thermal Gradient is now at a point where it believes it can produce its disposable PCR cartridges in large quantity and with low cost, according to Grover.

"We don't want to put a number in at this stage because we don't want to go on record saying we can make them for 'X' amount, [but] I think we're going to be extremely competitive with anybody trying to do high-speed PCR," he said.

"The main point here is that we're in production on the end-point device. We can make these in large quantities and yields are very high," Grover added. "We're looking at a system where a handful of copies in a reaction are going to be able to amplify up and be detected."

As a result, "if we put this into systems where we want to have extreme levels of sensitivity [like molecular diagnostics,] we're going to be able to do that," he added.

For the HIV viral load testing application in particular, Grover said this high sensitivity is a boon for the company.

"If you look at what commercial assays can do, they call for a good deal of amplification and we've now established that we can achieve the kind of amplification that commercial FDA-approved systems are able to achieve," he said.

For point-of-care applications, he explained, "while the kinds of amplification that the big clinical systems can do are probably not necessary most of the time … nevertheless from what we've seen, at least as far as the PCR part [of our technology] is concerned, there isn’t an obstacle to that," he said.

Moreover, "as far as readout is concerned, we've [also] shown that the real-time version of the chip will be able to have satisfactory detection capability."

He said the company will soon present more details about both the real-time PCR achievements and the sample prep component being integrated in the developing HIV assay, although he didn't elaborate.

Thermal Gradient's HIV assay effort began as a way for the company to move back to its original molecular diagnostics aspirations after starting life as a biodefense company in 2004. The end goal of the project is a system that can perform a sample-to-answer HIV test in about 30 minutes, Grover said last year.

Though details about the company's achievements with the HIV assay are still under wraps, Grover said that Thermal Gradient is now at the cusp of seeking partnerships to develop additional MDx assays.

"Now that we have something ready to go into production that has fully demonstrated performance and cost advantages, we're ready to partner up and get this to the market," he said.

Drug-resistant tuberculosis testing could be a "possible next step" and a "logical companion to the box we're developing under the NIH grant," he said. "We don't have any active research going on, but we're in contact with people who are very interested in that area and we're going to be exploring it," he added.

Other possible markets include testing for healthcare-associated or sexually transmitted infections, as well as genetic testing in the oncology area.

Grover said last year that the company hoped to demonstrate the HIV viral load test by the end of 2011, and do a pilot study by the end of 2012.

This week he said the company expects to release information about the performance of a sample-prep-integrated device in coming weeks, implying that the results so far have been positive.

Have topics you'd like to see covered in PCR Insider? Contact the editor at mashford [at] genomeweb [.] com.

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