NEW YORK (GenomeWeb) – Diamir, a developer of microRNA-based diagnostics, released new data suggesting that the expression signatures of a handful of the non-coding RNAs can be used to detect Parkinson's disease (PD), as well as differentiate it from Alzheimer's disease (AD).
The findings come as Diamir looks to expand upon a more-developed effort to develop a miRNA-based test for the early detection of mild cognitive impairment (MCI), which the company's top executive said is still on track for a potential market launch next year. The new data also come on the heels of the issuance of the firm's first US patent covering aspects of the method used in these tests.
Since its founding in 2009, Diamir has generated a body of data suggesting that levels of certain brain-enriched miRNAs can be used to differentiate MCI sufferers from age-matched healthy controls when used in combination with normalizer miRNAs obtained from areas of the brain unaffected by the condition.
For example, in 2012 the company reported in Aging that the miR-132 family and miR-134 miRNA families, paired with miR-491-5p and miR-370, respectively, could be used to identify MCI patients one to five years before clinical diagnosis with sensitivity of around 79 percent and specificity of up to 100 percent.
A follow-on validation study in larger independent sets of patients showed that expression of miR-132 family members could differentiate between MCI and age-matched controls with 84 to 94 percent sensitivity and 96 to 98 percent specificity. The miR-134 biomarkers, meantime, offered 74 to 88 percent sensitivity and 80 to 92 percent specificity.
According to Diamir CEO and co-founder Kira Sheinerman, the firm employed a similar approach for its PD and AD efforts, focusing on miRNA biomarker candidates from ones enriched in the midbrain/frontal cortex and hippocampus, respectively.
Once the candidates were identified, the company used a qRT-PCR approach to analyze plasma and serum samples of patients with either PD or AD, as well as age-matched controls, obtained from collaborators at the Roskamp Institute.
Diamir pinpointed 18 undisclosed miRNA biomarkers that could be used to differentiate PD patients from controls with an overall accuracy of 90 to 100 percent, sensitivity of 80 to 100 percent, and specificity of 95 to 100 percent.
PD patients could also be differentiated from AD patients and controls, the company said.
The findings were presented at this year's Biomarkers & Diagnostics World Congress in Philadelphia.
Sheinerman stressed that the AD/PD data are still preliminary, and that Diamir is continuing to validate the biomarkers in retrospective and prospective studies in larger cohorts of patients, including asymptomatic ones. At the same time, the company is expanding into other neurodegenerative diseases and expects to report new data throughout this year.
Meanwhile, Diamir is pushing ahead with its MCI-detection test, further refining it in anticipation of making it available to clinicians through a CLIA lab partner. The company sees utility for such a product ahead of neuroimaging and cerebrospinal fluid analyses, which can be costly and invasive, and as a way of identifying asymptomatic individuals who will go on to develop cognitive impairment so that they could be treated early.
While technical setbacks or funding issues could change Diamir's timeline, Sheinerman said that she anticipates the product becoming available in the first half of 2015.
Encouragingly, Diamir has also received a US patent — No. 8,648,017 — on its miRNA detection and analysis approach. Entitled "Methods of Using Small RNA from Bodily Fluids for Diagnosis and Monitoring of Neurodegenerative Diseases," the intellectual property claims the "detection of neuronal pathologies using quantitative analysis in bodily fluids of synapse and/or neurite small RNAs." It also covers the application of such methods for the "early diagnosis and monitoring of neurodegenerative diseases and other neurological disorders."
Sheinerman had previously noted that the US Supreme Court's ruling that human genes cannot be patented raises questions about the enforceability of patents covering specific miRNAs, adding that having IP protection around its analytical processes is expected to give Diamir a solid foundation for its upcoming products.