Parion Sciences and Gilead Sciences Sign Agreement to Advance Drug Candidates for Pulmonary Disease

Companies Will Initially Focus Research Efforts in Cystic Fibrosis

DURHAM, N.C. & FOSTER CITY, Calif.--(BUSINESS WIRE)--Aug. 15, 2007--Parion Sciences, Inc. and Gilead Sciences, Inc. (Nasdaq:GILD) today announced that they have entered into an exclusive licensing and co-development agreement focused on P-680, an epithelial sodium channel (ENaC) inhibitor discovered by Parion, a privately-held, development-stage pharmaceutical company dedicated to treating serious diseases resulting from the failure of the body's mucosal defenses. The agreement grants Gilead worldwide commercialization rights to P-680 for the treatment of pulmonary diseases, including cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD) and non-CF bronchiectasis. In addition, the companies will collaborate on a research program to identify other promising ENaC blocker-based drug candidates utilizing Parion's proprietary ENaC-based chemistry platform.

According to the terms of the agreement, Gilead will provide an upfront payment of $5 million for the license and make an additional $5 million investment in Parion. In addition, under the license, Gilead will supply research funding and may make payments upon achievements of certain milestones resulting in a potential deal value of approximately $146 million. Parion will perform the IND-enabling studies for P-680 and will transition development responsibilities to Gilead during the Phase I clinical trial period. Parion will also be eligible to receive up to double-digit royalties based on potential future product sales.

ENaC inhibitors are unique therapeutic agents that stimulate and maintain hydration on the body's mucosal surfaces, including those on the lung, mouth, nose, eye and gastrointestinal tract. Restoring the hydration of mucosal airway surfaces addresses the fundamental problem that produces infections in both acquired and genetic forms of chronic lung disease, including COPD and CF.

"This agreement validates the importance of ENaC inhibitors in the treatment of diseases involving defects in the innate defenses of the body's mucosal surfaces," said Paul Boucher, Director of Operations of Parion. "This partnership enables us to accelerate our development of P-680 and broaden our research programs. We are pleased to have the support of a company with an outstanding track record in the field of infectious diseases and pulmonary medicine."

"Gilead is committed to building a pipeline of novel respiratory therapeutics to advance the care of patients suffering from life-threatening diseases, and this partnership complements our program for development of aztreonam lysine for inhalation for treatment of CF-related lung infections," said A. Bruce Montgomery, MD, Senior Vice President, Head of Respiratory Therapeutics, Gilead Sciences. "We will work closely with Parion to complete preclinical development of P-680 in the hopes of advancing it into clinical studies."

About Parion Sciences

Based in Durham, NC, Parion Sciences is a privately-held, development-stage pharmaceutical company that is leveraging its proprietary small molecule chemistry and epithelial biology expertise to discover and develop an innovative pipeline of therapies for diseases resulting from the failure of the body's mucosal defenses, including chronic obstructive pulmonary disorder (COPD), cystic fibrosis, bronchiectasis, Sjogren's Syndrome and dry eye. Parion's lead product candidate, P-552, is currently in a Phase II clinical trial for the treatment of cystic fibrosis and Sjogren's syndrome. Parion was founded based on technology from University of North Carolina, Chapel Hill (UNC-CH) and has received grant funding from the National Institutes of Health (NIH) and the Cystic Fibrosis Foundation Therapeutics, Inc.

    For more information about Parion, please visit www.parion.com.

For more information about the Cystic Fibrosis Foundation, please visit www.cff.org.

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. Visit Gilead on the World Wide Web at www.gilead.com.

CONTACT: Gilead Susan Hubbard, Investors, 650-522-5715 Nathan Kaiser, Media, 650-522-1853 or Parion Paul Boucher, Director of Operations, 919-313-1195 or CLM Communications for Parion Carole Melis, 650-342-5686 SOURCE: Gilead Sciences, Inc.