The FDA has rejected aztreonam lysine for inhalation, Gilead's investigational therapy for cystic fibrosis patients who have Pseudomonas aeruginosa. The agency stated that they cannot approve the application in its current form and an additional clinical study will be required. Gilead said that it will work with the FDA to determine if further analyses of the data could lead to approval, or if the company will need to conduct another study as stated in the letter. Release