- Trial conducted by Novartis evaluating safety and efficacy of Albuferon administered every four weeks in combination with ribavirin in patients with genotypes 2 and 3 hepatitis C -

ROCKVILLE, Maryland – June 19, 2009 – Human Genome Sciences, Inc. (Nasdaq: HGSI) today announced that Novartis has completed enrollment and initial dosing in a Phase 2b clinical trial to evaluate the safety and efficacy of Albuferon® (albinterferon alfa-2b) administered monthly in combination with ribavirin in treatment-naive patients with genotypes 2 and 3 chronic hepatitis C. Albuferon is being developed by HGS and Novartis under an exclusive worldwide co-development and commercialization agreement entered into in June 2006.

“It is estimated that approximately 170 million people worldwide are infected with hepatitis C virus, including nearly four million in the United States,” said Stephen Pianko, M.D., F.R.A.C.P., Ph.D., Monash University, Melbourne, Australia. “Even In developed countries, fewer than half of those who have been diagnosed with chronic hepatitis C have undertaken treatment – in part due to the side effects associated with interferon injections, which are currently required on a weekly basis. A monthly dosing schedule with Albuferon may well result in more patients choosing to be treated.”

Mani Subramanian, M.D., Ph.D., Executive Director, Clinical Research - Infectious Diseases, HGS, said, “Novartis has made excellent progress in advancing the study of albinterferon alfa-2b dosed every four weeks. This dosing regimen of albinterferon alfa-2b, with a total of six injections, could offer an important treatment option if it demonstrates safety and efficacy comparable to peginterferon alfa-2a dosed once every week with a total of 24 injections.”

About the Design of the Phase 2b Monthly Dosing Trial

This Phase 2b trial is a randomized, open-label, multi-center, active-controlled, dose-ranging study to evaluate the safety and efficacy of albinterferon alfa-2b administered every four weeks plus daily ribavirin in treatment-naïve patients with genotypes 2 and 3 chronic hepatitis C. 391 patients were randomized in a 4:4:4:3 ratio into four treatment groups, including three that will receive albinterferon alfa-2b administered once every four weeks (900 mcg, 1200 mcg or 1500 mcg), in addition to the active-control group, which will receive peginterferon alfa-2a at the standard 180-mcg dose once every week. All patients in the study will receive 800-mg daily oral ribavirin. The total duration of treatment will be 24 weeks. The primary efficacy endpoint is sustained virologic response (SVR) at Week 48 (24 weeks following the end of treatment).

About Human Genome Sciences

The mission of HGS is to apply great science and great medicine to bring innovative drugs to patients with unmet medical needs. The HGS clinical development pipeline includes novel drugs to treat hepatitis C, lupus, inhalation anthrax and cancer.

The Company’s primary focus is rapid progress toward the commercialization of its two lead drugs, Albuferon® (albinterferon alfa-2b) for hepatitis C and BENLYSTA™ (belimumab, formerly LymphoStat-B®) for lupus. Albuferon has now completed Phase 3 development, and the filing of global marketing applications is expected in fall 2009. Two Phase 3 trials of BENLYSTA are ongoing, with results expected in July and November 2009.

In April 2009, HGS completed delivery of 20,000 doses of raxibacumab (ABthrax™) to the U.S. Strategic National Stockpile for use in the event of an emergency for the treatment of inhalation anthrax. The Company also has several drugs in earlier stages of clinical development for the treatment of cancer, led by the TRAIL receptor antibody HGS-ETR1 and a small-molecule antagonist of IAP (inhibitor of apoptosis) proteins. In addition, HGS has substantial financial rights to certain products in the GSK clinical pipeline including darapladib, currently in Phase 3 development as a potential treatment for coronary heart disease, and Syncria® (albiglutide), currently in Phase 3 development as a potential treatment for type 2 diabetes.

For more information about HGS, please visit the Company’s web site at www.hgsi.com. Health professionals and patients interested in clinical trials of HGS products may inquire via e-mail to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it or by calling HGS at (301) 610-5790, extension 3550.

For an Electronic Press Kit on this announcement, please click here.

HGS, Human Genome Sciences, ABthrax, Albuferon, BENLYSTA and LymphoStat-B are trademarks of Human Genome Sciences, Inc.

Safe Harbor Statement

This announcement contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The forward-looking statements are based on Human Genome Sciences’ current intent, belief and expectations. These statements are not guarantees of future performance and are subject to certain risks and uncertainties that are difficult to predict. Actual results may differ materially from these forward-looking statements because of the Company’s unproven business model, its dependence on new technologies, the uncertainty and timing of clinical trials, the Company’s ability to develop and commercialize products, its dependence on collaborators for services and revenue, its substantial indebtedness and lease obligations, its changing requirements and costs associated with facilities, intense competition, the uncertainty of patent and intellectual property protection, the Company’s dependence on key management and key suppliers, the uncertainty of regulation of products, the impact of future alliances or transactions and other risks described in the Company’s filings with the Securities and Exchange Commission. In addition, while the Company has completed delivery of ABthrax to the U.S. Strategic National Stockpile, the Company will continue to face risks related to FDA’s approval of the Company’s Biologics License Application for ABthrax. If the Company is unable to meet requirements associated with the ABthrax contract, future revenues from the sale of ABthrax to the U.S. Government will not occur. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today’s date. Human Genome Sciences undertakes no obligation to update or revise the information contained in this announcement whether as a result of new information, future events or circumstances or otherwise.

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301-315-2777

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