Gilead Sciences (NASDAQ: GILD) said today its inhalable antibiotic for cystic fibrosis beat a rival drug in a head-to-head clinical trial. The Gilead treatment, aztreonam lysine, was compared with Novartis’ inhalable antibiotic, tobramycin (Tobi), in 273 patients, most of whom had already gotten three cycles of the Novartis drug in the year before they entered the study. Researchers found that the Gilead treatment offered an 8.35 percent improvement on FEV1 scores, a measurement of how forcefully patients can blow air out of their lungs in one second. That was a statistically significant benefit when compared to patients who got another round of the competing drug, Gilead said. The Gilead drug won FDA approval in February.