ROCKVILLE, Maryland – November 9, 2007 – Human Genome Sciences, Inc. (Nasdaq: HGSI) today announced the presentation of Phase 2 clinical results demonstrating that LymphoStat-B® (belimumab) achieved a sustained improvement in disease activity across multiple clinical measures, decreased the frequency of disease flares over time, and was well tolerated through 2.5 years on treatment in combination with standard of care in patients with active systemic lupus erythematosus (SLE). The results will be the subject of an oral presentation today in Boston at the Annual Scientific Meeting of the American College of Rheumatology (ACR).
“SLE is a chronic disease, and patients need new therapies that provide durable efficacy with a favorable safety profile,” said Michelle A. Petri, M.D., M.P.H., Professor, Division of Rheumatology, Department of Medicine, Johns Hopkins University. “The Phase 2 results presented at ACR showed that the significant clinical benefit observed for LymphoStat-B in serologically active SLE patients at 52 weeks appears to be sustained through 2.5 years. We look forward to further evaluation of LymphoStat-B in larger Phase 3 studies, which are ongoing.”
A separate poster presentation of the safety profile of LymphoStat-B showed that LymphoStat-B was well tolerated in combination with SLE standard-of-care therapy during long-term exposure, with incidence rates of adverse events, serious adverse events, malignancies, infections and laboratory abnormalities remaining comparable to placebo or decreasing through 2.5 years of treatment (Merrill et al).
“The results through 2.5 years confirm and extend the results reported at Weeks 52 and 76,” said David C. Stump, M.D., Executive Vice President, Research and Development, HGS. “At Week 52 in LymphoStat-B patients with active SLE, we saw significant reductions in SLE disease activity versus placebo as measured by the SELENA SLEDAI and BILAG indices, the Physician’s Global Assessment, and, most importantly, by the response rate chosen as the primary efficacy endpoint of the Phase 3 trials. We are encouraged by the continued improvement in these patients, and by the improvement over time in patients crossing over from placebo to LymphoStat-B after 52 weeks. If the Phase 2 results are confirmed in our ongoing Phase 3 trials, we believe that LymphoStat-B could represent a breakthrough in the treatment of SLE.”
The primary objectives of the Phase 2 study were to evaluate the efficacy and safety of LymphoStat-B (belimumab) plus standard of care, versus placebo plus standard of care. A total of 449 patients with active SLE were randomized to receive one of three different doses of LymphoStat-B or placebo (1, 4 or 10 mg/kg) administered intravenously over a 52-week treatment period, in addition to standard-of-care therapy. At the end of 52 weeks, 345 patients chose to participate in an optional 24-week extension phase of the study, during which all patients received LymphoStat-B. At Week 76, 296 patients chose to remain on LymphoStat-B treatment in an open-label long-term continuation phase of the Phase 2 trial, in which all patients are receiving 10 mg/kg LymphoStat-B. As of October 1, 2007, 244 patients remained on LymphoStat-B treatment in the continuation study.
Key Findings to Date from the Phase 2 Study
In June 2006, HGS reported the 52-week results of the Phase 2 trial of LymphoStat-B in patients with SLE. The 52-week results demonstrated that LymphoStat-B significantly reduced disease activity versus placebo in patients with serologically active SLE across multiple clinical measures, exhibited clinically relevant biological activity, and appeared generally safe and well tolerated. Frequency and severity of adverse events were similar to placebo, with no increase at higher doses. Among the findings at Week 52 was a significantly improved response rate among serologically active patients, as defined by an improvement in SELENA SLEDAI score of 4 points or greater, no new BILAG A flare and no more than one new BILAG B flare, and no worsening in Physician’s Global Assessment (46% for LymphoStat-B versus 29% for placebo, p<0.01). This combination of measures is the primary efficacy endpoint in the ongoing pivotal Phase 3 clinical trials.
The data presented today at ACR 2007 demonstrated that LymphoStat-B achieved sustained improvement or stabilization of SLE disease activity in serogically active patients through 2.5 years. LymphoStat-B also decreased the frequency of SLE disease flares in these patients over time. The overall incidence of adverse events and laboratory abnormalities remained stable or decreased from Week 52 to Week 128.
The evidence of sustained clinical effect in serologically active SLE patients from Week 52 to Week 128 includes:
- An increase from 46% to 54% in the combined patient response rate selected as the primary efficacy endpoint of the Phase 3 trials. Among serologically active subjects who completed 128 weeks of treatment (n=175), 63% responded based on this measure of clinical effect.
- An increase from 49% to 58% in the proportion of patients who had improvement in SLE disease activity, as measured by SELENA SLEDAI (>4-pt reduction).
- A sustained improvement in the percentage of serologically active patients who experienced no new BILAG A organ flare and no more than one new BILAG B organ flare (92% at Week 52; 94% at Week 128).
- A sustained improvement in the percentage of serologically active patients showing no worsening in SLE disease activity, as measured by the Physician’s Global Assessment (<.03-pt worsening – 90% at Week 52 and 91% at Week 128).
- A decrease over time in the overall frequency of SLE disease flares, and in the frequency of severe disease flares, in patients who remained on LymphoStat-B through 2.5 years, as measured by the SELENA SLEDAI SLE Flare Index.
- Sustained response to LymphoStat-B therapy was independent of the type of autoantibody at baseline.
A separate poster presentation reported that LymphoStat-B also promoted progressive normalization of autoantibody, immunoglobulin and complement levels over 2.5 years of therapy in SLE patients (Stohl et al), including:
- Stable reductions in immunoglobulins, with no increase in infections or infectious events over time.
- Normalization of IgG in patients with elevated IgG at baseline; from 45% to 57% of patients with hypergammaglobulinemia at baseline normalized at Weeks 52-128.
- An increase in C3 and C4 complement among patients with low complement at baseline.
- Reversion of autoantibody levels from positive to negative (anti-dsDNA, anti-RNP, anti-Smith).
About LymphoStat-B
LymphoStat-B is a human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, or BLyS®. BLyS is a naturally occurring protein discovered by HGS that is required for the development of B-lymphocyte cells into mature plasma B cells. Plasma B cells produce antibodies, the body’s first line of defense against infection.
In lupus, rheumatoid arthritis and certain other autoimmune diseases, elevated levels of BLyS are believed to contribute to the production of autoantibodies – antibodies that attack and destroy the body’s own healthy tissues. The presence of autoantibodies appears to correlate with disease severity. Pre-clinical and clinical studies demonstrate that B-cell antagonists can reduce autoantibody levels and help control autoimmune disease activity.
About the Collaboration with GSK
In August 2006, HGS and GSK entered into a definitive co-development and co-commercialization agreement under which HGS has responsibility for conducting the LymphoStat-B Phase 3 trials, with assistance from GSK. The companies will share equally in Phase 3/4 development costs, sales and marketing expenses, and profits of any product commercialized under the agreement.
About Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE) is a chronic, life-threatening disease. The Lupus Foundation of America estimates that approximately 1.5 million Americans suffer from various forms of lupus, including SLE. More than 300,000 people are afflicted with SLE in the United States alone. Lupus can occur at any age, but appears mostly in young people between the ages of fifteen and forty-five. About 90 percent of the individuals diagnosed with lupus are women. African-American women are about three times more likely to develop lupus, and it is also more common in Hispanic, Asian and American Indian women. Symptoms may include extreme fatigue, painful and swollen joints, unexplained fever, skin rash, and kidney problems. Lupus can lead to arthritis, kidney failure, heart and lung inflammation, central nervous system abnormalities, inflammation of the blood vessels, and blood disorders. For more information on lupus, visit the Lupus Foundation of America at www.lupus.org, the European Lupus Erythematosus Federation at www.elef.rheumanet.org, or the National Institute of Arthritis and Musculoskeletal and Skin Diseases at www.niams.nih.gov.
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, anthrax disease, cancer and other immune-mediated diseases. The Company’s primary focus is rapid progress toward the commercialization of its two key lead drugs, Albuferon® for hepatitis C and LymphoStat-B (belimumab) for lupus. Phase 3 clinical trials of both drugs are ongoing.
ABthrax™ (raxibacumab) is in late-stage development for the treatment of anthrax disease, and the Company is on track to begin the delivery in 2008 of 20,000 doses of ABthrax to the Strategic National Stockpile under a contract entered into with the U.S. Government in June 2006. Other HGS drugs in clinical development include two TRAIL receptor antibodies for the treatment of cancers.
For more information about HGS, visit www.hgsi.com. To view the ACR oral presentation reporting results of the Phase 2 long-term continuation study of LymphoStat-B through 2.5 years, click here. To view the ACR poster presentation reporting the safety profile of LymphoStat-B through 2.5 years, click here. To view the ACR poster presentation reporting the progressive normalization of autoantibody, immunoglobulin and complement levels over 2.5 years of treatment with LymphoStat-B, click here. For more information on LymphoStat-B, visit www.hgsi.com/products/LSB.html. Health professionals or patients interested in LymphoStat-B clinical trials or other studies involving HGS products may inquire via the “Contact Us” section of the Company’s Web site, www.hgsi.com/products/request.html, or by calling (301) 610-5790, extension 3550.
HGS, Human Genome Sciences, ABthrax, Albuferon, BLyS and LymphoStat-B are trademarks of Human Genome Sciences, Inc.
HGS 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, the Company will continue to face risks related to animal and human testing, to the manufacture of ABthrax and to FDA concurrence that ABthrax meets the requirements of the ABthrax contract. If the Company is unable to meet the product requirements associated with the ABthrax contract, the U.S. government will not be required to reimburse the Company for the costs incurred or to purchase any ABthrax doses. 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.