GlaxoSmithKline has exercised its option to develop an antibiotic from Anacor Pharmaceuticals which has shown potential in early-stage studies.

The drug, known as GSK '052 (formerly AN3365). is a novel, systemic antibiotic derived from Anacor's boron chemistry platform. In early-stage studies, it has shown robust activity against multi-resistant gram-negative bacteria with no cross resistance to existing classes of antibiotics.

GSK '052 will be developed as a potential treatment for complicated urinary tract infection, complicated intra-abdominal infections and hospital/ventilator-associated pneumonia. Under the terms of the agreement, Anacor will receive an option exercise fee of $15 million and is eligible for various development and commercialisation milestone payments, plus royalties. GSK will now assume full responsibility for the compound.

David Payne, vice president of GSK's anti-bacterial drug discovery unit, said the drug “has an entirely novel mechanism of action with the potential to be the first new class antibacterial to treat serious hospital gram-negative infections in 30 years”. GSK '052 targets the bacterial enzyme leucyl tRNA synthetase and preclinical studies suggest that it is a promising compound for the treatment of infections caused by a broad range of gram-negative bacteria, including E. coli and K. pneumoniae.

GSK and Anacor signed their alliance for the discovery and development of viral and bacterial diseases in October 2007 and the collaboration provides the UK drugs giant with access to Anacor's boron-based chemistry for use in four target-based project areas.