Affimer

[17] Multimeric forms Affimers have been generated and shown to yield titres in the range of 200–400 mg/L under small-scale culture using bacterial host systems.

[2][18][19][20][21][22] Specific cysteine residues can be introduced to the protein to allow thiol chemistry to uniformly orient Affimers on a solid support eg ELISA plates.

As they are manufactured using recombinant bacterial production processes, the batch-to-batch consistency for Affimers is improved compared to polyclonal antibodies, overcoming some of the issues of reproducibility and security of supply.

This may represent advantages over antibodies in terms of tissue penetration, for example in solid tumours where Avacta are developing PD-L1 inhibitors as alternatives to Opdivo and Yervoy,[39] though requires half life modification to prevent rapid excretion through the kidney.

Examples include the production of multi-specific Affimer molecules to albumin binders to increase their half-life in vivo and for use as the targeting moiety in chimeric receptors or modified to carry a toxin in Affimer-drug conjugates.

[39][41][42][43] Early studies using ex vivo human samples showed low immunogenicity associated with the Affimer scaffold, at levels comparable to a marketed antibody therapeutic.