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GLASGOW, Scotland and BRISBANE, Calif. -- InterMune, Inc. has announced that in vitro studies of its novel antibiotic, oritavancin, demonstrate its potent activity against European isolates of susceptible and resistant strains of Staphylococcus, Streptococcus and Enterococcus. Researchers discussed the data from these studies in an oral presentation and two poster sessions at the European Congress of Clinical Microbiology and Infectious Disease (ECCMID).
Oritavancin, a second-generation glycopeptide antibiotic, is currently being tested in multiple clinical trials, including a multi-center, global Phase III study of more than 1,250 patients with complicated skin and skin-structure infections (CSSIs).
"These findings extend our knowledge of the potent in vitro activity of oritavancin against important and common gram-positive bacteria linked to CSSIs, beyond U.S. to European isolates, demonstrating oritavancin's similarly powerful activity against these organisms," said Steven Porter, MD, PhD, vice president of clinical research, InterMune. "Oritavancin demonstrated potent activity against all organisms tested. In particular, it was more bactericidal (i.e., it kills the bacteria) against enterococci than any other agent tested."
The promising in vitro potency of oritavancin has already been confirmed in a large-scale clinical trial. Data reported last year from a Phase III clinical study of 517 patients with CSSIs demonstrated that oritavancin intravenous therapy can reduce treatment times by one-half of the current standard of care -- intravenous therapy with vancomycin followed by oral therapy with cephalexin. InterMune completed enrollment of a second Phase III clinical trial of oritavancin and expects to report data later this year that will keep the company on track to file an NDA in the first half of 2004.
Staphylococcal infections, including CSSIs, represent a large market and high unmet medical need for new antibiotics. The rates of methicillin-resistant Staphylococcus aureus (MRSA) infections have risen dramatically in Europe. Approximately 30 percent to 40 percent of isolates of Staphylococcus aureus in some European countries are MRSA strains.
"These in vitro study results demonstrating oritavancin's bactericidal activity against gram-positive bacteria are especially compelling given the rising incidence of staphylococcal infections and increasing rates of MRSA infections in Europe," said Dr. Porter. "The potency of oritavancin suggests that it may become an important antibiotic addressing the challenge of antimicrobial resistance in staphylococcal, enterococcal and streptococcal infections in the hospital setting worldwide."
Oritavancin and comparator antibiotics were tested against susceptible and resistant strains of staphylococcus, streptococcus and enterococcus collected from patient specimens in 15 countries in Europe during the years 2000-2001. Broth microdilution methods were utilized and minimum inhibitory concentrations (MICs) for comparator agents were interpreted using the National Committee for Clinical Laboratory Standard's breakpoints published in 2002.
Results discussed in the oral presentation highlight oritavancin's consistent in vitro activity, compared to the other antibiotics tested, against susceptible and resistant isolates of Streptococcus pneumoniae collected from clinical samples of patients in 15 European countries. By minimum inhibitory concentrations, oritavancin was shown to be 32-fold more active than vancomycin and other comparator drugs evaluated. In addition, oritavancin showed consistent, potent activity against all strains of Streptococcus pneumoniae tested, regardless of resistance to other antimicrobial agents.
Data from several poster presentations demonstrated the consistent activity of oritavancin in vitro against susceptible and resistant strains of Staphylococcus aureus and coagulase-negative staphylococci (CNS), including multiple drug-resistant isolates. The activity of oritavancin, vancomycin, oxacillin, and comparator antibiotics were tested against susceptible and resistant isolates of staphylococci, including 697 isolates of Staphylococcus aureus and 265 strains of coagulase-negative staphylococci (CNS). Oritavancin showed consistent activity against susceptible and resistant strains of Staphylococcus aureus and CNS, including isolates that were resistant to five classes of antimicrobial agents.
A second poster presented highlighted the consistent activity of oritavancin in vitro against susceptible and resistant strains of Enterococcus (i.e., E. faecium (EM), E. faecalis (EF), and non-EM, non-EF enterococcal strains), including multiple-drug resistant isolates. Oritavancin and comparator antibiotics were tested against susceptible and resistant isolates of Enterococcus strains including 306 strains of E. faecium (EM), 388 strains of E. faecalis (EF), and 135 non-EM, non-EF enterococcal strains. Oritavancin was the most bactericidal agent tested and showed consistent activity against susceptible and resistant strains of EM and EF, including isolates resistant to multiple antibiotics.
InterMune is a commercially driven biopharmaceutical company focused on the marketing, development and applied research of life-saving therapies for pulmonary, infectious and hepatic diseases.
Source: InterMune, Inc.