Merck and Sanofi Pasteur Initiate Phase III Study in the United States of Pediatric Combination Vaccine to Help Prevent Six Infectious Diseases

WHITEHOUSE STATION, N.J. and LYON, FRANCE, - Merck (NYSE: MRK) (known outside the United States and Canada as MSD) and Sanofi Pasteur, the vaccines division of sanofi-aventis Group (EURONEXT: SAN, NYSE: SNY), announced today the initiation of a Phase III clinical program to evaluate the safety and immunogenicity of an investigational pediatric hexavalent combination vaccine¹. This combination vaccine is designed to help protect against six potentially serious diseases: diphtheria, tetanus, whooping cough (Bordetella pertussis), polio (poliovirus types 1, 2, and 3), invasive disease caused by Haemophilus influenzae type b, and hepatitis B.

The investigational vaccine is a combination of select components: DTaP5-IPV-Hib-HepB; Diphtheria and Tetanus Toxoids and Acellular Pertussis Adsorbed, Inactivated Poliovirus, Haemophilus b Conjugate (Meningococcal Outer Membrane Protein Complex), and Hepatitis B (Recombinant) Vaccine. The vaccine is being developed as part of a partnership between Merck and Sanofi Pasteur that focuses on the development of pediatric combination vaccines.

“Combination vaccines simplify the childhood immunization schedule and may improve coverage, on time vaccination and reduce the number of injections for children,” said Gary S. Marshall, M.D., professor of pediatrics, University of Louisville School of Medicine.

The Phase III clinical program will begin in the United States with a randomized, open-label, active-comparator controlled clinical trial that will involve approximately 1,440 infants at multiple centers. The primary study objectives are to assess the safety and immunogenicity of the investigational hexavalent combination vaccine when given at 2, 4, and 6 months of age concomitantly with Prevnar 13TM Pneumococcal 13-valent Conjugate Vaccine (Diphtheria CRM197 Protein) and ROTATEQ® (Rotavirus Vaccine, Live, Oral, Pentavalent). The clinical program is expected to begin in Europe this year. For more information on this study, please visit www.clinicaltrials.gov.

The Phase III program was initiated following results from a Phase IIb clinical trial of 459 children that assessed the safety and immunogenicity of the investigational combination vaccine.

“Based on the results of Phase II trials, we are pleased to move this investigational hexavalent combination vaccine to a late-stage clinical program,” said Michel DeWilde, Ph.D., senior vice president, Research and Development, Sanofi Pasteur. “We partnered with Merck to draw on the companies’ combined leadership, experience and expertise in the development, manufacturing and marketing of pediatric combination vaccines.”

In the United States, the Advisory Committee on Immunization Practices (ACIP), American Academy of Pediatrics (AAP), and American Academy of Family Physicians (AAFP) generally recommend the use of combination vaccines instead of individual injections, considering the potential for improved vaccination coverage.

“The need to consolidate vaccinations for infants will become increasingly important as the number of diseases that vaccines help prevent continues to increase,” said Tony Ford-Hutchinson, Ph.D., senior vice president, Vaccines Research, Merck. “The development of a hexavalent combination vaccine is complex. The ability to share expertise and capabilities with our partner Sanofi Pasteur is fundamental in reaching our shared goal of developing new combination vaccines that may improve vaccination rates of children.”

About Merck
Today’s Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching policies, programs and partnerships. For more information, visit www.merck.com.

About sanofi-aventis
Sanofi-aventis, a leading global pharmaceutical company, discovers, develops and distributes therapeutic solutions to improve the lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY). For more information, please visit: www.sanofi-aventis.com.

Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provides more than 1 billion doses of vaccine each year, making it possible to immunize more than 500 million people across the globe. A world leader in the vaccine industry, Sanofi Pasteur offers the broadest range of vaccines protecting against 20 infectious diseases. The company’s heritage, to create vaccines that protect life, dates back more than a century. Sanofi Pasteur is the largest company entirely dedicated to vaccines. Every day, the company invests more than EUR 1 million in research and development. For more information, please visit: www.sanofipasteur.com or www.sanofipasteur.us