NEW YORK (GenomeWeb) – Aiming to take advantage of the growing interest in exosome-based diagnostics, Aethlon Medical subsidiary Exosome Sciences has begun production of its ELLSA (enzyme linked lectin specific assay) diagnostic platform.
The company said last week that it planned to begin making the platform available to collaborators conducting research on exosomal biomarkers with the ultimate aim of developing new exosome-based molecular tests.
Additionally, Exosome Sciences will pursue development of companion diagnostics on the platform to accompany Aethlon's exosome-based therapeutic offering, the Hemopurifier, which uses the same underlying exosome-capture technology to clear disease-related exosomes from patient blood. Aethlon is currently recruiting patients for a clinical study to assess the safety of the Hemopurifier device as well as its effectiveness in reducing viral load in hepatitis C patients. The US Food and Drug Administration has also approved a study investigating the device for treatment of Ebola patients.
Founded in 1998, San Diego-based Aethlon began looking into the diagnostic potential of its lectin-based exosome capture technology around 10 years ago, Jim Joyce, the company's founder, chairman and CEO, told GenomeWeb. However, exosomes were not broadly perceived as being diagnostically useful at that time, he said, and so progress moved relatively slowly.
More recently, interest has grown in exosomes as potential disease biomarkers, Joyce said. "I think we have now, in the last couple of years, seen companies start to translate [exosome] research into potentially functional products that can have true meaning in the diagnostic space."
Among the leaders in the field is Exosome Diagnostics, which has commercialized exosome-based tests for measuring EML4-ALK mutations in lung cancer patients and plans in the near future to bring to market additional lung cancer tests as well as a prostate cancer test.
Also notable is start-up Codiak BioSciences, which was founded in 2015 to commercialize exosome-based therapeutic and diagnostic technology licensed from the University of Texas MD Anderson Cancer Center and has raised a total of $92 million in funding since its launch.
On the proteomics side, diagnostics firm NX Prenatal is developing a protein biomarker test for predicting spontaneous preterm delivery using exosome-bound proteins.
Exosomes are membrane-bound particles that are released by cells and contain molecular content including proteins and nucleic acids. They are interesting from a diagnostic standpoint in that they could present a more concentrated source of molecular information than, for instance, disease-related plasma proteins or circulating genomic material. This being the case, researchers hope that exosome-based analyses could provide advantages in terms of sensitivity and specificity and perhaps give them access to markers that would be otherwise unavailable.
Key to exosome analysis is, of course, the ability to isolate these vesicles. In the case of Exosome Sciences, the company's lectin-binding approach binds mannose structures on the exterior of exosomes
"Exosome isolation has been quite challenging in the sense of how do you isolate them without damaging them so they become viable biomarkers, and how can you do it efficiently," Joyce said. "And because we were looking at this strategy of leveraging lectin affinity, we came to understand that [the approach] is very good at binding certain pathogenic targets that carry a very unique high mannose signature on their surface, but it is not very effective at binding naturally occurring human proteins."
"So that was really very helpful for isolation where you pull down exosomes for certain disease populations," he said.
While much research into exosome-based biomarkers has focused on analyzing the molecular content inside the vesicles, Joyce said Exosome Sciences is more interested in using exosome surface markers, which, he suggested, could simplify the diagnostic process.
For instance, if a set of exosomes were found to express a certain factor on their surface characteristic of a given disease, the company could with its platform pull down a population of exosomes from patient blood or urine and then overlap an immunoassay to detect that factor.
Joyce cited work the company recently did in collaboration with researchers at the Morehouse School of Medicine in which they used the ELLSA platform to isolate urinary exosomes and then followed that with an antibody-based assay to detect HIV-specific exosomes. According to Joyce, the test was able to distinguish between 111 HIV-infected individuals and 35 HIV-negative controls with accuracy of 99 percent.
The company is also developing exosomal tau as a blood-based biomarker for possible use in Alzheimer's disease and Chronic Traumatic Encephalophathy.
Exosome Sciences plans to pursue additional collaborations in various disease areas, Joyce said, noting that it believed this was a more feasible approach than developing tests entirely in-house, given the broad range of diseases the company believes its technology can be applied to.
"Based on the way the exosome market is unfolding, we think we are going to have a much more expansive opportunity if we collaborate versus trying to advance individual tests on our own," he said.
The firm is not pursuing a straightforward fee-for-service model, though, but aims to capture some of the intellectual property that emerges from the collaborations. It recently hired business development personnel that will identify promising collaborations for the technology, Joyce said. He noted that of particular interest would be collaborations targeting conditions that Aethlon hopes to address with its Hemopurifier therapeutic device.
"From a corporate perspective, it could be very beneficial to us to try to advance companion diagnostics that marry up to therapeutic indications we are targeting," he said, noting that the company could potentially use the ELLSA platform to measure levels of the disease-related exosomes targeted by a Hemopurifier treatment, enabling it to predict and track the therapy's effectiveness.
Currently, Exosome Sciences shares essentially all of its personnel with Aethlon, Joyce said. He added, though, that over the next year Exosome Sciences will build an independent management team. He also said the company would likely seek additional funding in the next several years to accelerate the work underway at Exosome Sciences.