Gilead Sciences Submits Marketing Authorisation Application for Aztreonam Lysine 75 mg Powder for Nebuliser Solution

Gilead Sciences Submits Marketing Authorisation Application for Aztreonam Lysine 75 mg Powder for Nebuliser Solution, a Potential New Treatment for Cystic Fibrosis, to European Medicines Agency

FOSTER CITY, Calif. -- Gilead Sciences, Inc. (Nasdaq:GILD) today announced the submission of a Marketing Authorisation Application (MAA) for marketing approval of aztreonam lysine 75 mg powder for nebuliser solution (aztreonam lysine) in the European Union. The MAA will be reviewed by the Committee for Medicinal Products for Human Use (CHMP), subject to validation by the European Medicines Agency (EMEA). Review of the MAA will be conducted by the EMEA under the centralized licensing procedure, which, when finalized, provides one marketing authorization in all member states of the European Union. Aztreonam lysine is an investigational therapy in development for people with cystic fibrosis (CF) who have pulmonary Pseudomonas aeruginosa (P. aeruginosa) infection. Aztreonam lysine 75 mg powder for nebuliser solution is administered using an eFlow® Nebuliser (PARI GmbH).

The MAA is supported by data from two Phase III clinical studies (AIR-CF1 and AIR-CF2) and interim data from an ongoing open-label extension study (AIR-CF3) of patients who participated in AIR-CF1 or AIR-CF2.

“Chronic pseudomonal airway infection represents the single greatest cause of morbidity and mortality for people with cystic fibrosis, and with a limited number of inhaled antibiotics, there remains a significant unmet medical need,” said A. Bruce Montgomery, MD, Senior Vice President, Head of Respiratory Therapeutics, Gilead Sciences. “The submission of this MAA in the European Union further underscores Gilead’s commitment to advancing therapies for patients with this life-threatening disease.”

Aztreonam lysine 75 mg powder for nebuliser solution is an investigational therapy and has not yet been determined safe or efficacious in humans.

About Aztreonam Lysine 75 mg Powder for Nebuliser Solution

Aztreonam lysine 75 mg powder for nebuliser solution is an antibiotic candidate currently being studied in an ongoing Phase III open label trial for people with cystic fibrosis who have pulmonary P. aeruginosa. Aztreonam has potent activity against Gram-negative bacteria such as P. aeruginosa. Aztreonam formulated with arginine is a U.S. Food and Drug Administration (FDA)-approved agent for intravenous administration. Aztreonam lysine is a proprietary formulation of aztreonam developed specifically for inhalation and has been designated with orphan drug status in the United States and Europe.

In the United States, the investigational product is referred to as aztreonam lysine for inhalation. Gilead submitted its U.S. New Drug Application for aztreonam lysine for inhalation to the FDA on November 16, 2007. The FDA has established a target review date, under the Prescription Drug User Fee Act, of September 16, 2008. Gilead submitted its application in Australia on November 30, 2007.

About the AIR-CF Phase III Program

The Phase III AIR-CF clinical program was designed to determine the safety and efficacy of aztreonam lysine for use in people with cystic fibrosis who have pulmonary P. aeruginosa. In each of these studies, aztreonam lysine was administered by the PARI eFlow Electronic Nebulizer.

AIR-CF1 was a double-blind, randomized, placebo-controlled study designed to assess the safety and efficacy of a 28-day treatment course of aztreonam lysine in people with cystic fibrosis who have pulmonary P. aeruginosa. The primary endpoint was the change at day 28 from baseline in respiratory symptoms as assessed by the Cystic Fibrosis Questionnaire-Revised (CFQ-R). This study enrolled 164 patients who were randomized to receive 28 days of treatment with aztreonam lysine or volume-matched placebo administered three times daily. Results from this study were presented at the 21st Annual North American Cystic Fibrosis Conference (NACFC) in Anaheim, California on October 4, 2007.

AIR-CF2 was a randomized, double-blind, placebo-controlled study designed to assess the safety and efficacy of a 28-day treatment course with aztreonam lysine following a 28-day treatment course of tobramycin inhalation solution in people with cystic fibrosis who have pulmonary P. aeruginosa. Patients were randomized to receive 28 days of treatment with 75 mg of aztreonam lysine or volume-matched placebo each administered two times or three times daily. Patients were followed for an overall study period of 126 days, with 56 days of observation after receiving aztreonam lysine therapy or placebo. Results from this study were presented at the Cystic Fibrosis Therapeutics Development Network conference in Seattle, Washington on April 19, 2007 and at the European Cystic Fibrosis Society (ECFS) Conference in Belek, Turkey on June 14, 2007.

AIR-CF3 is an open-label, multi-center study of patients who participated in the AIR-CF1 or AIR-CF2 studies. The primary objective of the study is to evaluate the safety of repeated exposure to aztreonam lysine in people with cystic fibrosis. Patients will receive treatment with aztreonam lysine with the same dosing regimen they received in AIR-CF1 or AIR-CF2. This trial is ongoing. Limited interim data from this study were presented in a plenary session at NACFC on October 5, 2007.

About PARI Pharma and eFlow® Nebuliser

Aztreonam lysine 75 mg powder for nebuliser solution is delivered by an eFlow® Nebuliser, developed by PARI Pharma GmbH. eFlow is a portable nebuliser that enables aerosolization of liquid medications via a vibrating, perforated membrane. PARI Pharma also contributed to the development and optimization of the drug formulation (aztreonam lysine 75 mg powder for nebuliser solution) for delivery via eFlow. Based on PARI's 100-year history working with aerosols, PARI Pharma is dedicated to advancing inhalation therapies by developing innovative delivery platforms and new pharmaceutical formulations that work together to improve patient care.

About Cystic Fibrosis

Today, more than 70,000 people worldwide have cystic fibrosis. Cystic fibrosis is a chronic, debilitating genetic disease. A major characteristic of cystic fibrosis is production of abnormally thick, sticky mucus in the lungs that traps bacteria and predisposes people with cystic fibrosis to lung infections, which damage their lungs. Pulmonary infection with gram-negative bacteria, particularly pulmonary P. aeruginosa, represents the single greatest cause of morbidity and mortality among people with cystic fibrosis. Currently there is no known cure for cystic fibrosis, and the goal of cystic fibrosis therapy is to control symptoms and prevent further lung damage.

About Gilead Sciences

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Australia.

This press release includes forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995, that are subject to risks, uncertainties and other factors, including the risk that the EMEA, FDA or other regulatory agencies may not approve aztreonam lysine 75 mg powder for nebuliser solution for treatment of people with cystic fibrosis (CF) who have pulmonary P. aeruginosa infection, and any marketing approval, if granted, may have significant limitations on its use. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in Gilead's Annual Report on Form 10-K for the year ended December 31, 2007 filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements.