Abbott and Enanta Initiate Phase 1 Clinical Trial on ABT-450 HCV Protease Inhibitor

Abbott Park, Ill, and Watertown, Mass -- February 18, 2009 -- Abbott and Enanta Pharmaceuticals announced today the advancement of their hepatitis C (HCV) collaboration with a first-in-human study evaluating ABT-450, an oral protease inhibitor for the treatment of chronic HCV.

The objectives of the trial include assessment of safety, tolerability and pharmacokinetics. ABT-450 was discovered as part of a worldwide alliance between Abbott and Enanta to discover, develop and commercialize protease inhibitors for the treatment of HCV.

"Hepatitis C is a serious global health concern, with 170 million people currently infected by six different HCV genotypes," said John M. Leonard, MD, senior vice president, Global Pharmaceutical Research and Development, Abbott. "As a global leader in the development of antiviral therapies and diagnostics, Abbott is bringing its decades of antiviral experience, particularly with protease inhibitors, to this collaboration and to the fight against HCV."

"ABT-450 demonstrated favorable potency in vitro across various HCV genotypes and highly resistant strains," said Jay R. Luly, PhD, President and CEO of Enanta Pharmaceuticals. "We look forward to working with Abbott to advance ABT-450, and to our building a pipeline of HCV protease inhibitors that address this widespread disease."

Phase 1 Study Design

The Phase 1, double-blind, placebo-controlled study for ABT-450 announced today is a single, ascending oral dose trial in healthy volunteers.

About the Hepatitis C Virus

Hepatitis C is a liver disease affecting more than 170 million people worldwide. The virus is spread through direct contact with the blood of an infected person. Hepatitis C increases a person's risk of developing chronic liver disease, cirrhosis, liver cancer and death.

Liver disease associated with HCV infection is growing rapidly, and current therapies only provide sustained benefit in about half of patients with the genotype 1 form of the virus. Specifically targeted antiviral therapies for HCV, such as NS3/4a protease inhibitors, may have the potential to increase the proportion of patients in whom the virus can be eradicated.

About Enanta

Enanta Pharmaceuticals is a research and development company that uses its novel chemistry approach and drug discovery capabilities to create best-in-class small molecule drugs in the anti-infective field. Enanta is developing novel protease, polymerase and cyclophilin-based inhibitors targeted against the Hepatitis C virus (HCV). Additionally, the company has created a new class of macrolide antibiotics, called Bicyclolides, which overcomes bacterial resistance. Antibacterial focus areas include superbugs, respiratory tract infections and intravenous and oral treatments for hospital and community MRSA. Enanta is a privately held company headquartered in Watertown, Mass. Enanta's news releases and other information are available on the company's web site at www.enanta.com.

About Abbott

Abbott is working to advance the treatment of Hepatitis C (HCV) through a multifaceted discovery and development program that leverages the company's deep experience in antiviral medicines. Compounds in various states of development include protease inhibitors (ABT-450) and polymerase inhibitors (ABT-333 and ABT-072). In addition to developing HCV therapies, Abbott also offers laboratory tests for patient diagnosis, blood screening tests for hospitals and blood banks, and molecular diagnostic tests to measure HCV viral load and resistance.