In the dark on CF drug

Gilead Sciences Inc. and FDA aren't saying what was in the complete response letter for an NDA for an inhaled formulation of aztreonam lysine to treat patients with cystic fibrosis who have Pseudomonas aeruginosa lung infections. Whatever is holding up approval of aztreonam isn't obvious from the data that have been publicly disclosed.

Gilead spokesperson Amy Flood said the company did not want to jeopardize discussions with FDA, which asked the biotech to perform an additional clinical study prior to approval. Nor would she say when a trial might start or how many patients it would enroll. Flood did say the company will meet with FDA to determine whether it can respond using further analyses of existing data...