SEATTLE -- Telithromycin is highly active in vitro against community-acquired respiratory tract infections (RTIs), including bacterial strains resistant to several commonly used antibiotics, according to a PROTEKT US (Prospective Resistant Organism Tracking and Epidemiology of the Ketolide Telithromycin - United States) study presented today at the 2003 joint international conference of The American Lung Association and The American Thoracic Society (ALA-ATS). In vitro data suggest that telithromycin may offer potential for the initial treatment of RTIs, which could be of significance as the incidence of resistant bacteria increases.
PROTEKT is the only major multi-national surveillance study currently underway.
The PROTEKT US surveillance study was conducted using isolates of Streptococcus pneumoniae (the bacteria responsible for most common RTIs) collected from patients with RTIs from 206 medical centers across the United States during 2000-2001. Of the 10,103 isolates of Streptococcus pneumoniae collected, 26.3 percent were resistant to penicillin, 31 percent were resistant to erythromycin (a commonly prescribed macrolide) and 20.5 percent were resistant to both. Less than 1 percent of the isolates showed resistance to levofloxacin, a commonly prescribed fluoroquinolone.
Results from a second PROTEKT study also presented at ALA-ATS this week demonstrated that of the 2,706 H. influenzae (another commonly-occurring bacterium in respiratory tract infections) isolates studied, 28.4 percent produced b-lactamase, an enzyme that breaks down penicillin and other related antibacterials. Telithromycin in vitro activity, however, was unaffected by the presence of b-lactamase.
PROTEKT US is one of the largest surveillance studies in the United States, evaluating in its first year more than 17,000 pathogens in more than 206 sites across 44 states. The study was initiated in 2000 and was designed to monitor the spread of resistant phenotypes and genotypes of the major RTI pathogens across the nation. It is an ongoing study that is a branch of a larger international study called PROTEKT, which altogether includes more than 500 centers in 35 countries worldwide.
Telithromycin is the first in a new class of antibiotics known as ketolides. Telithromycin was designed to deliver a tailored spectrum of activity, with a short treatment duration, specifically for upper and lower RTIs. In clinical trials, the most commonly reported side effects (2 percent or more) were diarrhea, nausea and vomiting.
On January 27, 2003, Aventis received an approvable letter from the Food and Drug Administration (FDA) for telithromycin tablets for the treatment of community-acquired pneumonia (CAP), acute exacerbations of chronic bronchitis (AECB) and acute bacterial sinusitis (AS). In the approvable letter, the FDA requested that Aventis provide additional analyses and information prior to marketing approval. The agency has not required additional clinical studies. Aventis is currently preparing a response to the FDA's letter.