Amrad lands US asthma patent

The US Patent Office has granted Melbourne biopharma Amrad (ASX:AML) a patent on therapeutic antibodies that recognise for a sub-unit of the interleukin-13 (IL-13) receptor implicated in asthma.

Amrad and big pharma partner Merck, Sharpe and Dohme, are collaborating to develop monoclonal antibody therapies for asthma and other inflammatory respiratory disorders, that will target the IL-13 alpha-2 receptor subunit.

Amrad's interim CEO, Dr Andrew Nash, said the company had been involved in an "intensive process" of generating candidate monoclonal antibodies, and had selected one for preclinical trials.

Nash said the IL-13 receptor is assembled from protein sub-units, encoded by two different genes -- the alpha-2 subunit is shared with the IL-4 receptor, which has already been explored as a target for anti-inflammatory drugs for asthma, with little success.

Researchers from the Walter and Eliza Hall Medical Research Institute cloned the alpha-2 sub-unit gene, and Amrad acquired the IP through its association with the former CRC for Cellular Growth Factors.

Nash said several polymorphisms of the alpha-2 sub-unit have been linked to susceptibility to asthma and other inflammatory disorders.

The new antibody is designed to prevent or stop asthma by selectively blocking the IL-13 receptor through its action on the alpha-2 sub-unit, but with minimal effect on IL-4 receptor.

Preclinical trials will involve several animal models of asthma.

Nash described the US patent as an important commercial milestone for Amrad and Merck. "It protects our IP and provides market exclusivity in the world's most important pharmaceutical market."

Approximately 300 million people worldwide suffer from asthma, making it one of the most common of all inflammatory diseases. Nash said despite improved therapeutic agents, the death rate in some countries continues to increase, so new therapies are required.

The partnership deal with Merck, signed in June 2003, is potentially worth US$112 million in access payments, plus royalties on product sales. Amrad has already received milestone payments totalling AUD$15 million.