Human Genome Sciences Announces Positive Results in Second of Two Phase 3 Trials of Albuferon(R) in Chronic Hepatitis C

ROCKVILLE, MD--(Marketwire - March 9, 2009) -

--  900-mcg Albuferon (albinterferon alfa-2b) dosed every two weeks met
    the primary efficacy endpoint of sustained virologic response comparable to
    peginterferon alfa-2a dosed weekly in patients with genotype 1 chronic
    hepatitis C
--  Patients receiving 900-mcg Albuferon had comparable rates of serious
    and/or severe adverse events versus peginterferon alfa-2a
--  Filing of global marketing applications planned in fall 2009
    

Human Genome Sciences, Inc. (NASDAQ: HGSI) today announced that Albuferon® (albinterferon alfa-2b) met its primary endpoint of non-inferiority to peginterferon alfa-2a (Pegasys) in ACHIEVE 1, a Phase 3 clinical trial of Albuferon in combination with ribavirin in treatment-naive patients with genotype 1 chronic hepatitis C (p=0.0008). Albinterferon alfa-2b is being developed by HGS and Novartis under an exclusive worldwide co-development and commercialization agreement entered into in June 2006.

"These Phase 3 data show that, with half the injections, the efficacy of Albuferon was comparable to Pegasys," said H. Thomas Watkins, President and Chief Executive Officer, HGS. "We are pleased that Albuferon met its primary endpoint in the ACHIEVE 1 trial as it also did in ACHIEVE 2/3. We look forward to the filing of global marketing applications in fall 2009, following discussions with regulatory authorities. Assuming licensure, we believe Albuferon could become a market-leading treatment for chronic hepatitis C."

Stefan Zeuzem, M.D., Professor of Medicine and Chief, Department of Medicine, J.W. Goethe University Hospital, Frankfurt, Germany, said, "These Phase 3 results in patients infected with the genotype 1 virus, evaluated together with the previously reported Phase 3 results in patients infected with the genotypes 2 and 3 viruses, suggest that albinterferon alfa-2b has the potential to become an important new treatment option for chronic hepatitis C."

"We are encouraged that albinterferon alfa-2b met the primary efficacy endpoint of non-inferiority to peginterferon alfa-2a in both of our pivotal Phase 3 studies," said David C. Stump, M.D., Executive Vice President, Research and Development, HGS. "As we found with the earlier results from ACHIEVE 2/3, the ACHIEVE 1 data show that the rate of sustained virologic response was comparable for the treatment group receiving the 900-mcg dose of albinterferon alfa-2b every two weeks, versus the treatment group receiving the standard dose of peginterferon alfa-2a once weekly. Importantly, the rate of serious and/or severe adverse events was also comparable for these treatment groups. We were pleased to see that serious pulmonary adverse events in the 900-mcg group were infrequent and all resolved with cessation of treatment."

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