Alnylam Initiates Phase I Clinical Study of ALN-RSV01, an RNAi Therapeutic for the Treatment of Respiratory Syncytial Virus (RSV) Infection.

CAMBRIDGE, Mass. -- Alnylam Becomes a Clinical-Stage Company with the Industry's First Trial of an RNAi Therapeutic for Viral Infectious Disease 

Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that it has initiated a Phase I study in Europe to evaluate the human safety and pharmacology of ALN-RSV01, an RNAi therapeutic, in healthy volunteers. Additionally, the company's investigational new drug (IND) application to conduct a separate Phase I trial in the U.S. has cleared the 30-day review period by the Food and Drug Administration (FDA), and the U.S. study is expected to begin by the end of the month.

"The initiation of this Phase I study represents significant progress in the field of RNAi as it is the first clinical trial of an RNAi therapeutic to treat an infectious disease," said John Maraganore, Ph.D., President and Chief Executive Officer of Alnylam. "Importantly, this trial also marks Alnylam's transition to a clinical-stage company and is a major milestone in our continued effort to develop a pipeline of RNAi therapeutics to address major unmet medical needs."

"There is a significant need for novel therapeutics to effectively treat patients with RSV infection, a cause of serious disease and hospitalization in infants, the elderly, and others with compromised immune systems," said John P. DeVincenzo, M.D., Associate Professor of Pediatrics at the University of Tennessee Health Science Center. "Based on its novel mechanism of action and impressive pre-clinical efficacy data, ALN-RSV01 may represent a breakthrough treatment option for patients infected with RSV."

Trial Details

Alnylam will be conducting two Phase I trials with ALN-RSV01. The first trial is underway in Europe and is expected to enroll 57 healthy adult male volunteers. Drug or placebo will be administered intranasally in both single ascending doses across three cohorts and in multiple ascending doses daily for five consecutive days across three cohorts. The second trial, which is expected to initiate dosing by the end of the month, will be conducted in the U.S. and is expected to enroll 35 healthy adult male volunteers. Drug or placebo will be administered intranasally in single ascending doses across five cohorts. In both studies, ALN-RSV01 will be evaluated for safety, tolerability, and pharmacokinetics. Alnylam expects to have preliminary data available from these trials in the first half of 2006.

Pre-clinical Data

ALN-RSV01 is a small interfering RNA (siRNA) that is designed to selectively and potently silence the RSV nucleocapsid 'N' gene. This gene is among the most highly conserved genes in the virus and is essential for RSV replication. Data presented to date show both in vitro and in vivo efficacy of ALN-RSV01 in pre-clinical studies. Intranasally delivered ALN-RSV01 specifically inhibits RSV replication in animals and is active in the prevention and treatment of RSV infection. Additionally, Alnylam scientists have reported completion of GLP toxicology studies for ALN-RSV01 without any significant toxicities being observed.

About Respiratory Syncytial Virus (RSV)

RSV is a highly contagious virus that causes infections in both the upper and lower respiratory tract. RSV infects nearly every child at least once by the age of two years and is a major cause of hospitalization due to respiratory infection in children and people with compromised immune systems, and others. RSV infection typically results in cold-like symptoms but can lead to more serious respiratory illness such as croup, pneumonia, bronchiolitis, and in extreme cases, death. RSV infection in the pediatric population accounts for more than 100,000 hospitalizations per year in the U.S. The development of childhood asthma is also known to occur after childhood RSV infection. As a result, there is a significant need for novel therapeutics to treat patients who become infected with RSV.

About RNA Interference (RNAi)

RNA interference, or RNAi, is a naturally occurring mechanism within cells for selectively silencing and regulating specific genes. Since many diseases are caused by the inappropriate activity of specific genes, the ability to silence genes selectively through RNAi could provide a new way to treat a wide range of human diseases. RNAi is induced by small, double-stranded RNA molecules. One method to activate RNAi is with chemically synthesized small interfering RNAs, or siRNAs, which are double-stranded RNAs that are targeted to a specific disease-associated gene. These synthetic siRNA molecules are used by the natural RNAi machinery in cells to cause highly targeted gene silencing.

About Alnylam

Alnylam is a biopharmaceutical company developing novel therapeutics based on a breakthrough in biology known as RNA interference, or RNAi. The company, founded in 2002 by scientific pioneers in the field of RNAi, maintains a leadership position in fundamental patents, technology, and know-how relating to RNAi. Alnylam is applying its expertise in RNAi to address multiple therapeutic opportunities that cannot effectively be addressed with small molecules or antibodies, the two current major classes of drugs. The company's expertise in designing and optimizing RNAi therapeutics has enabled Alnylam to form major alliances with leading companies including Merck, Medtronic, and Novartis. The company's global headquarters are in Cambridge, Massachusetts, with an additional operating unit in Kulmbach, Germany. For more information, please visit www.alnylam.com.

Alnylam Forward-Looking Statements

Various statements in this release concerning our future expectations, plans and prospects, including our plans with respect to the initiation and completion of clinical trials of ALN-RSV01 and our views with respect to the potential for RNAi therapeutics, including ALN-RSV01, constitute forward-looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including risks related to: our approach to discover and develop novel drugs, which is unproven and may never lead to marketable products; our ability to obtain additional funding to support our business activities; our dependence on third parties for development, manufacture, marketing, sales and distribution of our products; the successful development of products, all of which are in early stages of development; obtaining regulatory approval for products; competition from others using technology similar to ours and others developing products for similar uses; obtaining, maintaining and protecting intellectual property utilized by our products; our dependence on collaborators; and our short operating history; as well as those risks more fully discussed in the "Certain Factors That May Affect Future Results" section of our most recent quarterly report on Form 10-Q on file with the Securities and Exchange Commission. In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. We do not assume any obligation to update any forward-looking statements.