Researchers at the Singapore Eye Research Institute have identified six peptide biomarkers linked to dry eye syndrome, which they plan to validate in a 400-patient trial done in collaboration with ocular pharmaceutical company Allergan using AB Sciex's TripleTOF 5600 mass spectrometer.
According to Roger Beuerman, SERI's senior scientific director and head of its Proteomics Research Group, the institute has developed a four-peptide panel that detected dry eye syndrome with 96 percent accuracy in an initial 130-subject study and has identified two additional markers capable of distinguishing between mild, moderate, and severe cases of the condition.
The SERI scientists used an Applied Biosystems Q-Star machine for the discovery phase of the study, but will be using the TripleTOF 5600 for the validation work. The facility purchased the instrument in December and expects that its speed will make it a good validation platform, Beuerman told ProteoMonitor.
"The [5600's] throughput is very fast, and now that we're dealing with hundreds of samples, it's got to be done in very rapid fashion," he said, noting that the researchers would be developing MRM assays for validation and could run roughly four samples on the machine every two hours.
He added that while his team hasn't done a direct comparison of the 5600's MRM capabilities compared to a standard triple-quadrupole, the instrument's sensitivity for such assays "is quite good" and its run times are shorter.
SERI has also been using the 5600 for a metabolomics study investigating the effects of contact lens wear that Beuerman's group has just submitted for publication.
Allergan's Restasis — the only drug on the market to treat dry eye syndrome — has been approved for use in the US and Canada, but the company has been unable to obtain regulatory approval in Europe in part because of the difficulty of defining an endpoint for the condition. As such, one aspect of SERI's biomarker work is aimed at establishing such a measurable endpoint, Beuerman said.
Dry eye diagnostic tests currently comprise a series of measurements including fluorescein staining and tear-breakup times, he said. "One problem is you do them in one clinic and another clinic doesn't quite agree with the same end point, so they're very subjective and it's affected drug development because the lack of a quantifiable endpoint makes it very hard to get drugs through [the regulatory process]."
The lack of quantifiable endpoints also makes it difficult to establish what the cutoff levels for SERI's biomarkers should be, Beuerman acknowledged. He suggested, though, that the establishment of peptide biomarker assays could help move the field toward an accepted endpoint.
"You're stuck with the clinical standard, so we have to base everything on the initial clinical standard," he said, "but as we move along we may be able to move away from that and replace the clinical point of view with objective biomarkers."
The researchers plan to start the validation trial by the end of this year and expect it to take roughly a year to a year and half including data analysis.
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