Phase III clinical trial data of Cayston versus TIS in CF patients with P. aeruginosa presented at ECFC 2010

Gilead Sciences, Inc. (Nasdaq: GILD) today announced that its head-to-head Phase III clinical trial of Cayston^® (aztreonam for inhalation solution) versus tobramycin inhalation solution (TIS) in cystic fibrosis (CF) patients with Pseudomonas aeruginosa (P. aeruginosa) achieved one of its co-primary endpoints of non-inferiority for mean percent change in forced expiratory volume in one second (FEV₁) percent predicted after 28 days of treatment. Patients receiving Cayston had a mean increase in FEV₁ percent predicted from baseline to Day 28 of 8.35 percent compared to 0.55 percent for patients receiving TIS, which meets the statistical definition of superiority. Safety results were similar across both arms of the study, with lower incidence of cough in patients receiving Cayston. These data were presented during a late-breaker oral session today at the 33^rd European Cystic Fibrosis Conference (ECFC) in Valencia, Spain.

“Inhaled antibiotic therapy has become the standard of care for treatment of chronic pseudomonal infection in people living with cystic fibrosis”

In the study, 268 patients were randomized to receive Cayston or TIS over a 24-week treatment period. Approximately 85 percent of patients in the study had received at least three courses of inhaled tobramycin in the 12 months prior to randomization. Final six-month study results will become available for presentation at a scientific conference later this year.

"Inhaled antibiotic therapy has become the standard of care for treatment of chronic pseudomonal infection in people living with cystic fibrosis," said Tacjana Pressler, MD, DSc, Copenhagen Cystic Fibrosis Center, National University Hospital, Copenhagen, Denmark. "As new inhaled antibiotic treatment options such as Cayston emerge, it is important that we have head-to-head clinical trial data comparing different treatment approaches. Results from this study suggest that Cayston may represent an important advance in anti-pseudomonal therapy for cystic fibrosis patients."

Cayston was approved by the U.S. Food and Drug Administration (FDA) in February 2010 and by the Australian Therapeutic Goods Administration (TGA) in January 2010. Cayston received conditional marketing authorizations in the European Union (EU) and Canada in September 2009. These conditional approvals are contingent upon results from this Phase III study. Gilead plans to begin submitting data from this study to regulatory agencies later this year.

"Given the chronic nature of pseudomonal infection and the potential for antibiotic resistance, it is important that cystic fibrosis patients have multiple treatment options," said Norbert W. Bischofberger, PhD, Gilead's Executive Vice President, Research and Development and Chief Scientific Officer. "This head-to-head study, along with other pipeline programs such as our ongoing Phase IIIb study in cystic fibrosis patients with Burkholderia cepacia, underscores Gilead's commitment to developing new treatments for cystic fibrosis and other serious respiratory conditions representing significant unmet medical need."