Antibody Alternative

In the last decade, antibody-based drugs have provided treatments for allergies, infectious diseases, cancers, and autoimmune diseases such as rheumatoid arthritis. But antibodies are large molecules, expensive to manufacture and tricky to maintain, requiring refrigerated storage. And extensive patent protections tie the hands of drug companies that want to expand their use.

Now researchers at biotech startup Avidia, in Mountain View, CA, have engineered a new class of proteins they call “avimers,” which the company says are easier to make and store – and require fewer lawyers to bring to market. Avidia scientists have shown that an avimer designed to inhibit human interleukin-6 (IL-6) – a protein implicated in rheumatoid arthritis and Crohn’s disease – works in mice. Avidia plans to move the avimer into human trials later this year.

Avimers derive from a related group of about 200 human-protein subunits. In the body, collections of these subunits fit together like Legos to form proteins that bind to small molecules and other proteins – exactly what any drug must do. Avidia scientists have varied the molecules’ building blocks to create a vast “library” of more than 100 million billion subunits. Linking together differing numbers and types of the variants “allows you to engineer proteins with a desired specificity for a target and to get very high affinities,” says George Georgiou, a protein engineer at the University of Texas at Austin.

Avidia scientists say they can design molecules to either inhibit or activate their targets and perhaps even bind to multiple targets simultaneously. Josh Silverman, an Avidia senior scientist, says the company’s initial sights are on drugs for cancers and autoimmune diseases.