British life sciences firm Avacta Group has begun commercialization of its affimer protein affinity reagents with the aim of launching by the end of this year a high-content microarray product and custom reagent services based on the molecules.
The company also this week announced a collaboration with Liverpool University researcher Rob Beynon on combining the affimer technology with mass spectrometry for biomarker and drug target discovery.
Launched in 2004 as a spinout of Leeds University, Avacta went public in 2006, listing its shares on the London Stock Exchange's AIM market. The company houses three business units – Avacta Analytical, Avacta Animal Health, and Avacta Life Sciences, the third of which was recently launched to house its affimer commercialization efforts.
The company as a whole posted 2013 revenues of £2.7 million ($4.4 million), though its Life Sciences division has only recently begun to generate sales CEO Alastair Smith told ProteoMonitor.
Potential alternatives to antibodies, affimers are based on the protein stefin A and can be engineered to bind to a wide range of protein targets. The reagents, Smith said, offer comparable sensitivity and specificity to antibodies while having a shorter development time of five to seven weeks compared to months or even a year for a monoclonal antibody of similar quality.
The reagents are also less expensive to produce, Smith noted, though he said that the company plans to price them roughly the same as quality antibodies.
Avacta is taking several different tacks to commercializing the reagents. Currently, the company offers researchers customer affirmer development to their targets of interest, a business for which, Smith said, it recently secured its first customers.
It is also working on developing a catalog of affimers to protein research targets for which there are either no antibodies or where existing antibodies perform poorly. The company aims by the end of the year to have an initial catalog offering in the range of the "high tens to 100" targeted affirmers, Smith said, adding that he expected expansion of this catalog to accelerate in the following year. He noted, however, that while in principle the company would be able to produce hundreds of new reagents per year, the time required for optimization and validation of those reagents would likely prove to be the bottleneck in terms of adding content to its catalog.
Avacta is also planning this year to launch high-content arrays of what Smith called "naive" affimers – reagents not targeted to any specific molecule. In this, the company is pursuing an approach somewhat similar to companies like Opko Health and Arizona State University spin-out HealthTell, which uses high-content peptide arrays for protein biomarker discovery.
"While each affimer has an unknown target, we know from the work we have done to date that a few percent of those affimers in the array will bind specifically to a target in serum, cell lysate, tissue lysate," Smith said. "So we know that with an array of 50,000 or so affimers we are likely to see several hundred of those specific interactions, which [makes for] a really interesting unbiased discovery tool."
Avacta has established a facility for high-throughput production of these naive affimers and is currently making around 2,000 per week, Smith said. It aims by the end of this year to produce arrays containing on the order of 50,000 affimers aimed at the biomarker discovery market.
"We're now in the position where we can produce those [affimers] and print them and are at the point of doing the final QC on some prototype arrays," he said. The company has partnered with Arrayjet for commercial production of the arrays.
The company's recently announced collaboration with Liverpool's Beynon concerns the next step in the process – how to follow up on the hits identified by the high-content naive arrays.
"You can imagine that when an end user of our array does that initial discovery experiment on a very large array and gets, say, 1,000 interesting hits, there has to be some decisions made about the workflow from that point," Smith said.
One option, he noted, would be to identify the affimers in the array that scored the hits, and generate new versions of those reagents to pull out the observed targets from samples of interest so they could be subjected to mass spec analysis.
"So it's that whole workflow … and we are working with Beydon's group to finesse that and figure out what the customer is going to want to do," Smith said. Waters is also participating in the project but as a collaborator with Beydon, not Avacta, he noted.
Looking beyond this year, Avacta has longer term plans to develop smaller, specialized arrays targeted to specific research interests as well as smaller custom arrays that researchers can use to follow up on hits identified in discovery work using the larger arrays.
It also plans to use the reagents for internal diagnostic and therapeutic research, though, Smith said, the company has no ambition of becoming a diagnostics or therapeutics firm. Instead, he said, it would seek to license out any discoveries that emerged from this work.