AstraZeneca starts final-stage tests on severe asthma drug

LONDON (Reuters) - AstraZeneca said on Thursday it was starting final-stage Phase III clinical trials for its experimental drug tralokinumab as a treatment for severe asthma. The drug, which showed promising results in mid-stage trials in May, was among those highlighted by AstraZeneca as part of its defense against an abortive $118 billion takeover bid by Pfizer. Like many of AstraZeneca's biggest new drug hopes, the medicine was developed by MedImmune, the U.S.-based biotech company acquired by AstraZeneca in 2007. Several firms are racing to develop injectable biotech asthma drugs for patients with severe disease who do not respond well to traditional inhalers, in pursuit of a new market worth a possible $7.5 billion a year. (Reporting by Ben Hirschler, Editing by Paul Sandle)