Safety and immunogenicity data available for new pertussis booster vaccine candidate for adolescents


Data presented for first time at the 44th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)

WASHINGTON, D.C., November 1, 2004 – GlaxoSmithKline (NYSE:GSK) today reported results from a pivotal clinical study of its booster vaccine candidate, BoostrixTM [Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine, Adsorbed (Tdap)]. The Phase III clinical trial involved over 4,000 adolescents in the United States and showed Boostrix to be comparable to a U.S.- licensed Tetanus Diphtheria (Td) vaccine with regard to safety and immunogenicity. In addition, the use of Boostrix induced anti-pertussis antibody levels which exceeded (by 1.8 to 6.9 times) those observed in infants following primary immunization 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.

Currently, pertussis vaccination in the U.S. is only approved for children under the age of seven. Immunity from childhood vaccination generally wears off after five to 10 years, leaving many adolescents susceptible to this highly contagious disease. Boostrix, for which a biologics license application is currently under review by the U.S. Food and Drug Administration (FDA), was developed to offer extended protection against pertussis (whooping cough) to adolescents between the ages of 10-18 by combining a pertussis vaccine with the routine tetanus/diphtheria booster.

"We are extremely pleased with the results of this study," said Leonard Friedland, M.D., Director, Clinical Research and Development and Medical Affairs, Vaccines North America, GlaxoSmithKline. "If approved, using a Tdap vaccine as a replacement or alternative for the routine adolescent Td booster could offer important protection against pertussis, as well as diphtheria and tetanus, without an additional injection or doctor's office visit."

Study Findings

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 measured and were found to exceed pertussis antibody concentrations observed in infants, following primary immunization with a DTaP vaccine (Infanrix®), in whom efficacy against pertussis disease was demonstrated;

  • The incidence of solicited local and general side effects was comparable between the Boostrix and Td groups.

    Background on Pertussis

    Pertussis is a highly contagious bacterial infection of the respiratory system that causes spasms of severe coughing. It is spread through airborne droplets of an infected person's cough or sneeze. The first symptoms of pertussis are similar to the "common cold" with a mild fever, runny nose and a cough.

    Symptoms generally progress to more severe coughing episodes, often with a high-pitched "whoop," followed by vomiting. Adolescents generally exhibit different symptoms of the disease, often without the classic "whoop," making it more difficult to recognize and diagnose. Severe coughing episodes can lead to vomiting, a hernia, or even a broken rib. Although pertussis is rarely fatal for older sufferers, this highly contagious disease can be deadly in infants who are too young to be fully immunized. Up to 90 percent of non-vaccinated household members may develop the disease when exposed to people infected with pertussis.

    Reported cases of pertussis – once a common childhood illness – dropped dramatically after routine childhood immunization was introduced in the 1940s. However, reports of pertussis in the U.S. have been rising since the mid-1970s. According to the Centers for Disease Control and Prevention (CDC), there were over 11,000 cases in 2003 – the highest number of reported cases in nearly 40 years. Thirty –nine percent of cases reported to the CDC in 2003 occurred in adolescents 10-19 years of age. Pertussis, significantly under-reported and under-recognized, is a common cause of prolonged cough illness in adolescents and adults. In a clinical study involving 442 adolescents and adults who had a cough-related illness for seven or more days, approximately 20 percent of these patients had laboratory-documented pertussis.

    In addition to the public health threat pertussis poses, the disease also has economic repercussions. A cost-benefit analysis for the use of a pertussis booster vaccine in adolescents projected that vaccination of people in the U.S. ages 10-19 during a 10-year period would prevent up to 1.8 million cases of pertussis and save as much as $1.6 billion in direct and indirect costs.

    "Pertussis is the only disease for which children are routinely vaccinated that is on the rise in the U.S. – particularly amongst adolescents. However, there is currently no pertussis vaccine recommended for people age seven or older. GlaxoSmithKline is pleased with the results of this study, which demonstrate the potential to add pertussis protection to the currently recommended tetanus and diphtheria booster shot for teenagers," noted Dr. Friedland.

    Background on Diphtheria and Tetanus

    Diphtheria is a serious disease that results in the death of approximately five to 10 percent of infected persons. Symptoms may include sore throat, low-grade fever and neck swelling.

    In more serious cases, a membrane can form over the airway and result in respiratory obstruction. Causes of death can also include heart failure. Most cases of diphtheria occur among unvaccinated or inadequately vaccinated persons.

    Tetanus (lockjaw) is a severe, often fatal disease. The bacteria that cause tetanus are widely found in soil and the manure of many animals. Almost all reported cases of tetanus are in persons who have either never been vaccinated, or who completed a primary series, but have not had a booster in the preceding 10 years. Infants of unvaccinated mothers are at risk for neonatal tetanus. Early symptoms are lockjaw, stiffness in the neck and abdomen, and difficulty swallowing. Later symptoms may include fever, elevated blood pressure and severe muscle spasms.

    GlaxoSmithKline: A Leader in Vaccines

    GlaxoSmithKline, with U.S. operations in Philadelphia, PA, and Research Triangle Park, N.C., is one of the world's leading research-based pharmaceutical and healthcare companies and is committed to improving the quality of human life by enabling people to do more, feel better and live longer.

    Source: Eurekalert & others

    Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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