Avacta Life Sciences is investing £10m in the launch of Affimers, the engineered alternative to antibodies.

Affimers are small single domain proteins derived from a lysosomal protease inhibitor that are engineered to solve several significant problems faced by commercial and academic researchers using antibodies.

Whereas custom antibodies typically take seven to 10 months to produce and have a high failure rate, screening against a library of 10¹³ Affimers takes seven weeks and has a 90% success rate. Affimers are direct replacements for antibodies at comparable cost, requiring no change to lab workflow.

Affimers are produced in vitro, meaning that their generation does not rely on an animal’s immune system, which opens up areas of research where antibodies cannot be generated by traditional methods.

Avacta Life Sciences illustrate the potential for Affimers by pointing to the area of ubiquitylation, where in the 10 years since the Nobel prize was awarded in this field only two antibodies have been identified.  Avacta has produced four Affimers in a matter of months and more are in the pipeline.

Specificity can be controlled and Affimers are robust and stable with consistent batch to batch reproducibility. Another significant benefit is that Affimers are direct replacements for antibodies and do not require the end user to change their workflow or processes.

Fluorescent dyes or other tags can be attached to Affimers to enable them to be used in a wide range of applications.

Affimers differ significantly from nucleic acid aptamers in that they use a protein scaffold to present the interaction surface yielding high affinity, specific binders.  Affimers require no special assay conditions unlike aptamers the core scaffold doesn’t bind to proteins in human samples such as , serum or plasma and they are biologically and biophysically stable.

The Affimer IP is unencumbered making licensing as straightforward as possible, in contrast to aptamers were there is uncertainty over the IP position.

Avacta Life Sciences offers both custom Affimer development as well as a simple e-commerce site where customers can choose from a catalogue.

In the custom Affimer service offering, once the target antigen is received the company performs an in vitro selection against very large Affimer libraries, a 10¹⁰ phage display library and a 10¹³cis-display library. When the screening is complete, candidate binders are expressed and their performance assessed in house. A selection of the best binders is moved forward to affinity purification and then exogenous and endogenous western blots are performed and the best candidates sent to the customer.

From this selection the customer can test which is their preferred Affimer and they then receive the plasmid for this Affimer and a license for its use for R&D.

The initial research behind Affimers was conducted over 12 years at the MRC Cancer Centre in Cambridge and developed at the University of Leeds Institute for Molecular Medicine.

The patents for this work were acquired by Avacta Life Sciences in 2012 and the company has raised £10m via a share placing by its AIM listed parent Avacta Group to scale up its production facilities and its commercial capabilities in anticipation of a launch to the market. The company recently expanded its senior management team by appointing Dr Matt Johnson who was formerly Head of R&D at Abcam to head up R&D and operations.

The company has just launched a new website which allows customers to buy from the catalogue in a simple e-commerce platform.

“Our patented technology offers reliable and easy to adopt solutions to some really widespread and difficult problems in a global market worth billions and we have the resources and backing to scale up rapidly as demand grows” says Alastair Smith, CEO of Avacta.

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