Safety and Immunogenicity Results Available for New Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Booster Vaccine (Tdap) Candidate for Adolescents

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Safety and Immunogenicity Results Available for New Tetanus Toxoid, Reduced

Diphtheria Toxoid and Acellular Pertussis Booster Vaccine (Tdap) Candidate

for Adolescents

Data Presented for First Time at the 44th Interscience Conference on

Antimicrobial Agents and Chemotherapy (ICAAC)

WASHINGTON, Nov. 1 /PRNewswire-FirstCall/ -- GlaxoKline (NYSE: GSK)

today reported results from a pivotal clinical study of its booster vaccine

candidate, Boostrix [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, GlaxoKline. " 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, greater than or equal to 99.9 percent of

subjects had anti-diphtheria and anti-tetanus concentrations greater

than or equal to 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. GlaxoKline 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.

GlaxoKline: A Leader in Vaccines

GlaxoKline, 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 GlaxoKline

Web Site: http://www.gsk.com