Issued: Monday 7 February 2011, London UK and Rockville, Maryland, US

GlaxoSmithKline (GSK) and Human Genome Sciences, Inc. (Nasdaq: HGSI) today announced publication of the BLISS-52 study of Benlysta® (belimumab) in autoantibody-positive patients with active systemic lupus erythematosus (SLE) in The Lancet .

The BLISS-52 study, one of two pivotal Phase III trials, was a double-blind, placebo-controlled, multi-centre superiority trial to evaluate the efficacy and safety of belimumab plus standard of care, versus placebo plus standard of care, in autoantibody-positive patients with active SLE. BLISS-52 randomised and treated 865 patients at 90 clinical sites in 13 countries, primarily in Asia, South America and Eastern Europe. The Phase III programme for belimumab is the largest clinical programme ever conducted in patients with SLE.

A Comment accompanying The Lancet article was authored by John H. Stone, M.D., of Massachusetts General Hospital and Harvard Medical School.

Belimumab is an investigational drug and the first in a new class of drugs called BLyS-specific inhibitors. It is being developed by GSK and HGS under a co-development and commercialisation agreement entered into in 2006. The FDA has assigned Benlysta a Prescription Drug User Fee Act target date of 10 March, 2011.

GlaxoSmithKline – one of the world’s leading research-based pharmaceutical and healthcare companies – is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For further information please visit www.gsk.com. GSK Biopharm R&D is employing novel approaches to harness the therapeutic potential of biopharmaceuticals for the benefit of patients with serious autoimmune disease.

Human Genome Sciences - exists to place new therapies into the hands of those battling serious disease.

For more information about HGS, please visit the Company’s web site at www.hgsi.com.

HGS, Human Genome Sciences, and BENLYSTA are trademarks of Human Genome Sciences, Inc. Other trademarks referenced are the property of their respective owners.

GlaxoSmithKline Cautionary statement regarding forward-looking statements Under the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Factors that may affect GSK' s operations are described under 'Risk Factors' in the 'Business Review' in the company' s Annual Report on Form 20-F for 2009.

HGS Safe Harbor StatementThis 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 Human Genome Sciences’ unproven business model, its dependence on new technologies, the uncertainty and timing of clinical trials and regulatory approvals, Human Genome Sciences’ 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, Human Genome Sciences’ 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 SEC. 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.