ID Biomedical Announces Immunogenicity Results from Phase II Trial of Streptavax

VANCOUVER -- ID Biomedical Corporation announced that it has completed its final analysis of immune responses of adults in its Phase II trial of StreptAvax vaccine, the companys subunit protein-based vaccine against group A streptococcal diseases. The trial enrolled 90 healthy adult subjects, 70 of whom received StreptAvax and 20 of whom received hepatitis A vaccine as a comparator. All subjects received three doses of vaccine, and serum antibody responses were measured after the third dose.

StreptAvax is designed to induce protective immune responses to 26 different M protein serotypes of group A streptococci which are responsible for causing the vast majority of disease, including the types that are the most common causes of strep throat and invasive infections (so-called flesh-eating disease) in North America as well as the types historically associated with the most feared complication of strep throat -- acute rheumatic fever. In addition, the vaccine also includes a 27th peptide derived from another protein, called Spa, which is expressed by many important pathogenic strains of streptococci.

The results reported show that, among the 70 subjects who received StreptAvax, there was a statistically significant (p less than 0.0001) increase in serum antibodies to every one of the 26 M protein serotypes, and to the Spa protein. The average increase in antibody levels across the population of StreptAvax recipients was 11.3-fold for each vaccine peptide.  Viewed as individuals, StreptAvax recipients responded to a median of 25 (91 percent) of the different streptococcal peptides in the vaccine, and each peptide elicited a significant immune response in a median of 87 percent of vaccinees. By way of contrast, the group of 20 subjects who received hepatitis A vaccine had no significant antibody increase against any of the streptococcal peptides.

The pattern of overall safety established in the Phase I trial continued in this study.

These new data confirm both the impressive strength and breadth of the immune response and are consistent with our Phase I data. Additionally, StreptAvax continues to have a relatively benign safety profile. The strong and consistent antibody response data, combined with the absence of significant safety findings, will lend strong support to the entry of StreptAvax into pediatric populations, said Louis Fries, MD, vice president of clinical affairs for ID Biomedical.

Over the past year, ID Biomedical has made preparations for StreptAvax clinical testing in pediatric populations. ID Biomedical has developed a unique database of the normal variation of echocardiograms over time in healthy children, which will allow this diagnostic test to be used accurately as a safety monitoring tool in pediatric subjects. In addition, the company has developed and qualified a new quantitative immunoassay method for group A streptococcal antibodies for the volumes of serum available from small children.

The company expects the final one-year safety analysis on all adult data, as well as manufacturing data from additional production runs, to be ready toward the end of the first quarter in support of a pre-IND meeting with the FDA focusing on pediatric trials strategy. The company plans to begin Phase II pediatric clinical testing later in 2005. This initial study is expected to include both dose-finding and age step-down components.

About Group A streptococcal infections

Group A streptococcus is responsible for common infections of the throat (strep throat) and skin. Left untreated, these infections can lead to life-threatening diseases such as necrotizing fascitis (flesh-eating disease) and toxic shock syndrome. In addition, infections with group A streptococci can trigger a variety of serious post-streptococcal diseases, including rheumatic fever, post-streptococcal glomerulonephritis (a form of kidney disease), and neurologic abnormalities.

In the United States alone it is estimated that there are 25 million to 35 million doctor visits each year for suspected group A streptococcal infections, making it one of the most common childhood illnesses for which no preventative vaccine exists.

Source: ID Biomedical