Pharmaceutical giant AstraZeneca said Phase III studies into investigative drug PT003 for chronic lung disease had delivered positive results.The two 24-week studies examined whether the drug, which the group acquired after buying Pearl Therapeutics two years ago, improved the conditions of patients suffering from lung disease.The drug combines a long-acting beta-2 agonist (LABA) and a long-acting muscarine antagonist (LAMA) and the FTSE 100 group said it plans to file PT003 for approval this year.In both studies, the treatment showed significant improvements in trough forced expiratory volume in one second when compared with each drug used individually and a placebo."The ability to deliver a unique LAMA/LABA formulation in a single pressurised metered dose device is important for helping some 30% of patients around the world who use an aerosol inhaler," said Briggs Morrison, executive vice president, global medicines development and chief medical officer at AstraZeneca.AstraZeneca shares were up 0.55% to 4,665.50p at 08:16 on Wednesday.