GlaxoSmithKline initiates head-to-head study of cervical cancer vaccines Study to compare immunogencity of GSKâ€™s cervical cancer candidate vaccine, CERVARIXÂ® , to Merckâ€™s GardasilÂ® London, UK & Philadelphia, PA - GlaxoSmithKline announced today the initiation of the first study of its kind designed to compare the immunogenicity of its cervical cancer candidate vaccine, CERVARIXÂ®, versus GardasilÂ®. The primary objective of the head-to-head trial is to compare the immune responses to HPV types 16 and 18 in U.S. women 18 to 26-years-old. Secondary objectives include evaluating the immune responses to HPV 16 and 18 in women 27 to 35-years-old and 36 to 45-years-old. In addition, the study will compare immune responses to other cancer-causing HPV types. Initial study results are anticipated 12 months after studyenrollmentis completed, and extended follow up will continue for another 17 months. "Vaccination to prevent cervical cancer may be the most significant healthcare breakthrough for women in our lifetime,â€ said Dr. Mark M. Blatter, Medical Director of Primary Physicians Research in Pittsburgh, PAand study investigator. â€œThis unprecedented trial, which willenrollmore than 1,000 women,will provide the first scientific evidence to demonstrate how the two vaccines differ with respect to inducing strong and sustained immune responses in women who may be appropriate for vaccination.â€ Data published in Vaccine in August 2006 demonstrated GSKâ€™s cervical candidate vaccine, formulated with the proprietary adjuvant system AS04, induced higher antibody levels and more robust immune memory response compared to the same HPV vaccine composition conventionally formulated with aluminium hydroxide adjuvant alone. Furthermore, data published in The Lancet in April 2006 provided evidence that GSKâ€™s cervical cancer candidate vaccine demonstrated protection up to 4.5 years against persistent infection with HPV 16 and HPV 18 â€” the two most common cancer-causing HPV types â€” and protection from pre-cancerous lesions. Protection was also demonstrated against infection with the third and fourth most prevalent cancer-causing types of HPV, namely types 45 and 31. Collectively, HPV types 16, 18, 45 and 31 are responsible for approximately 80 percent of cervical cancer cases globally. â€œGSK is focused on protecting women from cervical cancer, a devastating disease that often strikes women in the prime of their lives,â€ said Gary Dubin, Vice President, HPV Vaccines, GlaxoSmithKline. â€œBy conducting this study, we hope to further the scientific understanding of the role of strong and sustained immune responses to HPV vaccination for the benefit of all women.â€ Notes to editors: About the Study This is a Phase III, randomized, observer-blind, multicenter study, to be conducted among 1,042 patients in the United States. There will be two arms of the study, one arm receiving GSKâ€™s cervical cancer candidate vaccine, one arm receiving GardasilÂ®, and each arm will be stratified by age (18-26 [n=374], 27-35 [n=334], 36-45 [n=334]). The primary objective of the study is to compare GSKâ€™s cervical cancer candidate vaccine to GardasilÂ®, in terms of immune responses to the two most common cancer-causing HPV types 16 and 18, which are responsible for at least 70 percent of all cervical cancers worldwide, in adult women aged 18 to 26. Secondary objectives will assess immune responses to cancer-causing HPV types 16 and 18 in adult women aged 27 to 35, and 36 to 45 as well as evaluate immune responses to other cancer-causing HPV types. Results are expected 12 months after patient enrollment is complete, with extended follow up continuing for approximately 17 months after the last study visit (month 7 through month 24). About Cervical Cancer The American Cancer Society estimates that in 2006, nearly 10,000 women were diagnosed with cervical cancer and nearly 4,000 died from this disease in the Unites States in a single year. After breast cancer, cervical cancer is the second most frequently occurring cancer in women ages 20 to 39 in the United States. About GlaxoSmithKlineâ€™s Cervical Cancer Candidate Vaccine GSKâ€™s cervical cancer candidate vaccine was developed to prevent infection and lesions from the two most prevalent cancer-causing types of HPV, specifically HPV 16 and 18. It is formulated with the proprietary adjuvant system, AS04, selected to ensure that this vaccine confers strong and sustained antibody levels over time. More than 16,000 women worldwide have been vaccinated with GSKâ€™s cervical cancer candidate vaccine as part of completed and ongoing clinical trials.Phase III studies are under way in more than 25 countries with more than 35,000 subjects enrolled in ongoing trials. GSK plans to file a biologics license application for CERVARIXÂ® for U.S. Food and Drug Administration review by April 2007 for its cervical cancer candidate vaccine. The company submitted a marketing application review to the European Agency for the Evaluation of Medicinal Products in March 2006. Other international regulatory filings followed in Australia, parts of Asia and parts of Latin America in March 2006. About GlaxoSmithKline In the next two to five years, GSK expects to launch more major new vaccines in the United States, for example, a vaccine against rotavirus, an improved flu vaccine for the elderly and a meningitis combination vaccines for various ages, including infants. GlaxoSmithKlineâ€“one of the worldâ€™s leading research-based pharmaceutical and healthcare companiesâ€“is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For company information, please visit www.gsk.com. GSK Biologicals (GSK Bio), one of the worldâ€™s leading vaccine manufacturers, is headquartered in Rixensart, Belgium, where the majority of GlaxoSmithKlineâ€™s activities in the field of vaccine research, development and production are conducted. GSK Bio employs more than 1,500 scientists, who are devoted to discovering new vaccines and developing more cost-effective and convenient combination products to prevent infections that cause serious medical problems worldwide. In 2005, GSK Bio distributed more than 1.2 billion doses of vaccines to 165 countries in both the developed and the developing world, an average of more than 3 million doses per day. Cautionary statement regarding forward-looking statements Under the safe harbor provisions of the US Private Securities Litigation Reform Act of 1995, the company cautions investors that any forward-looking statements or projections made by the company, 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 the Group's operations are described under 'Risk Factors' in the â€˜Operating and Financial Review and Prospectsâ€™ in the company's Annual Report on Form 20-F for 2005.