Pertussis
New US Vaccine for Adolescents Against Pertussis
By GlaxoSmithKline
May 3, 2005, 23:22

GlaxoSmithKline (NYSE: GSK) today announced that its booster vaccine, Boostrix� [Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine, Adsorbed (Tdap)] received approval from the United States (U.S.) Food and Drug Administration (FDA). Boostrix is indicated to be given as a single dose to individuals aged 10 to 18 years thereby adding a pertussis component to the routine tetanus/diphtheria booster currently administered to teens. Previously, there was no pertussis vaccine approved for use in the United States in children seven years of age or older. Immunity from childhood vaccination generally begins to wear off after five to 10 years, leaving many adolescents susceptible to this highly contagious disease.

"The introduction of Boostrix marks a milestone in the fight against pertussis in the United States, particularly among adolescents who are an important reservoir for the disease and often the source of infection for infants," said Gary Marshall, M.D., professor of Pediatrics, University of Louisville School of Medicine, Louisville, Kentucky. "Adding pertussis to the current tetanus and diphtheria booster shot for teens is a logical strategy to prevent this disease in adolescents � without additional injections."

Reported cases of pertussis have risen nearly 20-fold since 1976. According to the Centers for Disease Control and Prevention (CDC), there were almost 20,000 cases in 2004 � the highest number of reported cases in more than 40 years.

In addition, experts believe the disease is underreported and estimate that the true incidence of the disease in the United States may be greater than one million cases per year. Adolescents aged 10 � 19 are being hit particularly hard, with almost 40 percent of cases reported to the CDC in 2004 occurring in this age group. Alarmingly, there was a 743 percent increase in reported adolescent pertussis cases in the last decade. Teens, in whom classic signs and symptoms of pertussis are often absent, may go undiagnosed and be the source of infection for susceptible family members.

"GlaxoSmithKline is proud to introduce Boostrix in the United States," said Barbara Howe, M.D., vice president, Clinical Research and Development and Medical Affairs, Vaccines North America, GlaxoSmithKline. "Boostrix is approved in many other countries, and we believe that this vaccine, which adds a pertussis component to the routine tetanus/diphtheria booster currently recommended for adolescents, will be an important tool in preventing pertussis among teens � a population in which there is a significant disease burden."

Boostrix [Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine, Adsorbed (Tdap)] Clinical Trials In making its decision, the FDA reviewed several clinical trials which included safety and immunogenicity data from one pivotal trial, which studied Boostrix in approximately 3,000 adolescents in the United States, aged 10 to 18. The Phase III clinical trial showed Boostrix to be comparable to a U.S.- licensed Td vaccine [Tetanus and Diphtheria Toxoids for Adult Use] with regard to overall safety and immunogenicity. In addition, the use of Boostrix induced anti-pertussis antibody levels which were non inferior to those observed in infants following a primary immunization series with a DTaP vaccine (Infanrix?) [Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed] in whom efficacy against pertussis disease was demonstrated in a previous study. As compared to Infanrix, the ratio of geometric mean antibody levels to pertussis antigens following the use of Boostrix ranged from 1.9 to 7.3.

In this observer-blinded, randomized, controlled, multi-center clinical trial, 4,114 healthy 10-18 year-olds were vaccinated with one dose of Boostrix or a U.S.-licensed Td vaccine. Each subject had completed his or her routine childhood vaccinations against diphtheria, tetanus and pertussis according to the U.S. recommended schedule. According to study results:

# In both treatment groups, > 99.9 percent of subjects had anti-diphtheria and anti-tetanus concentrations > 0.1 IU/ml, indicating seroprotection against diphtheria and tetanus

# In the Boostrix treatment group, the levels of anti-pertussis antibodies, anti-PT, anti-FHA and anti-PRN were found to be non inferior to pertussis antibody concentrations observed in infants, following primary immunization with a DTaP vaccine (Infanrix), in whom efficacy against pertussis disease was previously demonstrated

# The overall safety profile was comparable between the Boostrix and Td groups

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