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UK Dx Firm Avacta Readies High-Density 'Affimer' Protein Array Platform for 2014 Debut


British diagnostic tools provider Avacta plans to introduce a new high-density protein microarray platform for use in drug and biomarker discovery by the end of next year, CEO Alastair Smith told BioArray News this week.

High-density protein arrays of various stripes are currently commercially available or in development — Roche NimbleGen, for example, already provides some customers with 2.1-million-feature peptide arrays. Avacta's platform, however, is based on a new class of affinity reagents, called Affimers, that it claims are superior to other binding molecules. Avacta snatched up the technology and related IP when it acquired Leeds-based Aptuscan for £1.5 million ($2.2 million) last year, and as such has sole commercialization rights.

According to Smith, each Affimer consists of a small human protein that can be engineered to bind with high specificity and affinity to a wide range of protein targets. According to the firm, the reagents are based on the human protease inhibitor stefin A.

Avacta is positioning Affimers as a "biophysically and biochemically robust" alternative to antibodies, which are the go-to biomolecule of biopharmaceutical and diagnostics developers for testing and visualizing proteins. In a recent statement, Avacta claimed that Affimers' advantages over antibodies include "reduced manufacturing costs, shorter development times, and zero cross-reactivity."

One competitor will likely be SomaLogic, a Boulder, Colo.-based company. SomaLogic relies on so-called Somamers, chemically modified nucleic acid aptamers, to bind to target proteins. SomaLogic's assay then converts target protein concentration to specific Somamer concentration, which is then quantified with readily available DNA technologies, including microarrays (BAN 6/15/2010 ).

Smith said that Wethersby-based Avacta has set up a "high-throughput protein expression and purification suite" that is capable of producing around 2,000 Affimers a week in its current form and is being used to produce the company's forthcoming protein chips.

"A clean room microarray production facility is now in place with early prototype arrays being produced to allow the manufacturing process to be optimized," Smith said. The firm plans to eventually outsource array production to Roslin, UK-based Arrayjet, with whom Avacta is currently working to optimize manufacturing conditions, Smith said.

Prototype arrays containing 20,000 Affimers have already been made available to researchers at a number of UK institutes, including the UK National Institute for Health Research's Leeds Musculoskeletal Biomedical Research Unit and the University of Liverpool, Smith said, noting that "early data using tissue homogenates, cell culture lysates, and serum are encouraging." He added that pre-launch validation of the firm's Affimer arrays with clinical, academic, and commercial partners is a "key milestone" towards Avacta's goal of commercialization.

The company aims to make arrays containing about 50,000 Affimers available as a commercial product "by late 2014 if development progress is good," Smith added.

Revenue Generation

Spun out of the University of Leeds in 2004, Avacta became a public company in 2006 when its shares were listed on the London Stock Exchange's AIM market. Since that time, the company has maintained two business divisions: Avacta Analytical, which provides the Optim 2 instrument for protein analysis and characterization; and Avacta Animal Health, which will begin selling its AX-1 immunoassay system and accompanying Sensitest allergy testing menu this spring. In Avacta's most recent annual report, which was published in October 2012, the firm posted £3.1 million in revenues for the 12 months ended July 31, 2012, a 28 percent increase year over year; and a net loss of £1.6 million, roughly in line with the previous year's loss.

According to a company statement, Avacta's Affimer-derived products will be commercialized through its two existing business divisions. Though the products have yet to generate revenue, Smith said in the statement that Avacta "anticipates revenue generation" from the products, including Affimer arrays, next year, and that Avacta is "confident that the investment we are currently making into Affimers will develop high-value products with substantial market interest."

Paul Ko Ferrigno, the firm's director of advanced technologies, recently presented Affimer array data at the Annual Biomarker Congress held in Manchester, UK. According to a company statement, Ko Ferrigno demonstrated the use of the arrays to generate a list of proteins that are cleaved in apoptosis, and to identify candidate biomarkers of inflammatory and cardiovascular disease in human serum.

Given the different applications highlighted in Ferrigno's talk, Smith told BioArray News that Avacta could make multiple, custom arrays available to clients in the future.

"All the Affimers in such arrays are proprietary to Avacta and have completely unencumbered IP with no royalty stack," said Smith. "Avacta therefore anticipates that the use of its Affimer discovery arrays will lead to the demand for smaller custom arrays for development and validation purposes and license deals for the individual Affimers that prove to have clinical utility," he added.

Avacta has said previously that, beyond their use in arrays and as life science reagents, Affimers could be used as therapeutic agents. However, Smith said that drug development is "not a focus for Avacta Group" and that the company would instead pursue potential licensing partners for therapeutic applications of the Affimers.