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VolitionRx Bets on Canine Cancer Screening Test as Nucleosome Tech Development Continues


NEW YORK – Epigenetics diagnostics firm VolitionRx is expanding its veterinary business while developing tests to diagnose cancer and other diseases in humans, all based on information contained in nucleosomes.

In March, the Austin, Texas-based firm signed a $28 million exclusive global supply and licensing agreement with Heska to sell its Nu.Q Vet Cancer Screening Test for companion animals at the point of care, consisting of a $10 million upfront payment and $18 million based on the achievement of certain milestones. In addition, last month, Volition appointed Sage Healthcare as its distributor for the test in Singapore.

Nu.Q, short for nucleosome quantification, is the company's core technology. It consists of an ELISA assay targeting histone H3.1 to extract free nucleosomes, segments of DNA wound around histones that can be found at elevated levels in the blood of cancer patients.

According to the firm, circulating nucleosomes and nucleosome modifications are known cancer biomarkers but relatively few diagnostic tools target them.

Mainstream thinking, asserted Jake Micallef, Volition's CSO, holds that chromatin and its related proteins can be excluded from patient samples, in favor of things such as circulating tumor DNA, which can be sequenced.

"Our philosophy," he continued, "is that this stuff isn't junk; it actually contains a huge amount of information. And not only is it not junk, but it can be accessed more quickly and more cheaply."

Dying cells release nucleosomes into the bloodstream following apoptosis, where they remain fairly stable and can be detected via ELISA. Increased cell death during cancer and other biological processes such as inflammation leads to a higher nucleosome concentration in the blood.

Volition had already been developing nucleosome capture and quantification assays for human cancers, but encountered challenges in bringing human assays to market, largely due to the costs of running an adequately powered clinical trial. 

In 2018, Volition reached out to Heather Wilson-Robles, a professor of veterinary oncology at Texas A&M and the chief medical officer of Volition Veterinary Diagnostics Development, the company's veterinary subsidiary, regarding the possibility of adapting the company's technology for canines. According to Micallef, the regulatory market surrounding pet diagnostics is more relaxed than that for humans, enabling a quicker route to market, and revenue generated by sales of a canine test could help advance the company's other lines of research.

"The nucleosome compartment had never been characterized in the dog before, so we didn't know what was the best sample, when you should pull it, how you should process it, all those things," said Wilson-Robles.

Hematological cancers are more common among dogs than humans, but nothing had to be altered in adapting the company's tests to a canine population.

"There are really almost no differences between different mammalian histones and nucleosomes, so what works in humans also works in horses and dogs and cats," Micallef said.

The Nu.Q Vet test coexists with a handful of other canine cancer products. PetDx, for example, launched its own cancer screening assay, called OncoK9, last year, and One Health Company launched its canine cancer diagnostic platform, FidoCure, in 2019.

Where Nu.Q Vet screens for signs of cancer with a simple ELISA test, the other canine cancer-focused companies employ next-generation sequencing methods to go beyond simply detecting cancer. FidoCure also says that it looks for cancer mutations shared between humans and dogs for which targeted treatments might be available.

"NGS-based liquid biopsy has the capability to establish if a cancer signal is detected, and due to the depth of high-quality data generated for each sample, it additionally has the potential to discriminate among different cancer types based on the unique genomic signature within that individual sample," Daniel Grosu, founder and CEO of PetDx, said via email.

He added that "single biomarker testing using much older ELISA-based technology does not have the capability to identify the origin of the cancer."

Louise Batchelor, Volition's chief of marketing and communications, commented that the company is positioning Nu.Q Vet as part of an overall wellness test.

"The test, as it is today, is for animals that are otherwise healthy," she said. "It's basically to say, hey, there's something going on here, you need to look further."

"I think it probably makes sense that we would be a frontline test and that on a positive test, [NGS assays] would probably be able to give more information," Micallef added.

At issue is that other biological processes such as inflammation and obesity also lead to higher nucleosome concentrations in the blood, potentially confounding an attempt to screen specifically for cancer.

Wilson-Robles led a study evaluating the Nu.Q technology in dogs that was published last year in BMC Veterinary Research. While this case-control study demonstrated a clear ability to distinguish between healthy dogs and those with cancer, it did not rule out the real-world possibility of a positive finding being unrelated to cancer.

To provide more detailed diagnostic information in the future, Volition is investigating the follow-on use of assays such as sequencing and mass spectrometry to derive more information from nucleosomes, such as cancer subtype and specific mutations, which could impact treatment decisions. 

"We're looking at using [nucleosome enrichment] in conjunction with mass spectrometry to aid biomarker discovery," Batchelor said.

The firm has published some of its findings with mass spectrometry, and Batchelor said that papers focusing on sequencing are forthcoming.

Micallef suggested that Nu.Q Vet is sufficiently low-cost and rapid that it can serve as an early diagnostic before more expensive NGS-based assays.

Nu.Q Vet costs approximately $50 and has a turnaround time of three to five business days, for example, compared to a five to 10-day turnaround for OncoK9. This time may fall to minutes once Heska begins selling Nu.Q Vet on its Element i+ bioanalyzer device later this year. The Element i+ is a cartridge-based benchtop device that veterinarians can operate at the clinic.

In the meantime, Volition has continued to develop its human nucleosome assays. For example, it is currently co-sponsoring a study on colorectal cancer biomarkers run by the National Cancer Institute's Early Detection Research Network.

While Volition continues to expand the commercial reach of Nu.Q Vet, the company is also focusing on adapting its core technology to capturing and analyzing neutrophil extracellular traps (NETs).

NETs form when neutrophils extrude their chromatin during an immune reaction, using it to trap things such as foreign bodies and cancer cells. Some recent research has suggested that the level of NETs an individual with cancer has correlates with their likelihood of developing metastasis.

Volition is funded by a combination of capital raises, at-the-market stock offerings, milestone payments, and, going forward, revenue from products and services.

As of March 31, the firm had cash and cash equivalents of $23.7 million. Batchelor commented that slightly over $13 million of that comes from non-diluted funding, mainly from the Walloon government in Belgium, where the firm's lab is located and the majority of its R&D takes place.