Biotech major Amgen is planning to buy fellow US company Avidia to get hold of a platform technology that promises to improve the targeting and efficacy of protein-based drugs.

Amgen will pay $290 million for privately-held Avidia, as well as up to $90 million in milestone payments, and the transaction is expected to close before the end of the year.

Avidia’s lead compound is an inhibitor of interleukin-6, C326, which is in Phase I trials and has potential in the treatment of inflammatory and autoimmune diseases, including Crohn’s disease. If successful in trials C326 could complement Amgen’s anti-inflammatory franchise, currently headed by anti-TNF drug Enbrel (etanercept) which is already sold for Crohn’s, rheumatoid arthritis and other indications.

But the main interest for Amgen comes in the broad potential of the platform technology, known as Avimer. This involves the creation of single protein chains, like beads on a string, which allow modular binding domains to be included in a single molecule.

As a result, protein drugs can be designed that deliver their payload more selectively to their target site, sparing healthy tissues and improving the safety of treatment, according to Avidia.

"The Avimer technology is among the most attractive protein-based technologies currently under development," Roger Perlmutter, Amgen's executive vice president for research and development, said in a statement.

Amgen has already snapped up one biotech this year, buying Abgenix for $2.7 billion in order to secure full rights to colorectal cancer drug Vectibix (panitumumab) which won US approval last week.