RGPI: Telavancin as Effective as Vancomycin in Skin Infections

NIAGARA-ON-THE-LAKE, Ontario, Oct. 11 -- The novel antibiotic telavancin is as effective as vancomycin in treating complicated skin and skin structure infections caused by Gram-positive bacteria, researchers said today.

Combined data from two large Phase III trials -- the ATLAS-1 and ATLAS-2 studies -- consistently favored telavancin in terms of efficacy, although the advantage did not reach statistical significance, investigators told the International Symposium on Resistant Gram-Positive Infections here.

The safety profile for telavancin was also similar to that of vancomycin according to Ralph Corey, M.D., of the Duke Clinical Research Institute in Durham, N.C. Dr. Corey was principal investigator.

"Telavancin has a safety profile that is compatible with treatment of serious infections due to resistant bacteria," Dr. Corey said.

One of the most striking aspects of the two trials was the high number of patients with methicillin-resistant Staphylococcus aureus (MRSA), commented Stephen Zinner, M.D., of Harvard Medical School.

"To me, what's most impressive about these studies is the sheer number of MRSA patients that they have," Dr. Zinner said in an interview. Dr. Zinner conducted in vitro studies of telavancin and has been a consultant for the company that makes the drug, but he was not an investigator on either trial.

The two ATLAS studies were randomized double-blind multinational trials that enrolled and treated 1,867 patients, of whom 1,489 were clinically evaluable. Among those, 979 had an S. aureus infection, of which 579 (62%) were methicillin-resistant.

Interestingly, Dr. Corey said, the proportion of MRSA patients in the study is a reflection of the increasing importance of the infection. In earlier studies of antibiotic therapy for complicated skin and skin-structure infections, the proportion of MRSA among S. aureus patients ranged from 2% in 2000 to 21% in 2004.

Telavancin is an intravenously administered lipoglycopeptide peptidoglycan inhibitor that has shown activity against Gram-positive bacteria, Dr. Corey told the meeting. The efficacy endpoints in each study were the clinical cure rate in the clinically evaluable population and in those with MRSA, Dr. Corey said.

The study found:

• The combined clinical cure rates were 88.3% for telavancin and 87.1% for vancomycin (for an odds ratio favoring telavancin of 1.2, with a 95% confidence interval from minus 2.1 to 4.6.).
• The clinical cure rates in MRSA patients were 90.6% for telavancin and 86.4% for vancomycin (for an odds ratio favoring telavancin of 4.1, with a 95% confidence interval from minus 1.1 to 9.3.).

The most common adverse events were taste disturbances, in 33% of telavancin patients and 7% of vancomycin patients, followed by nausea, vomiting, and headache. In the telavancin arm, 7% of adverse events were judged to be severe, compared to 4% in the vancomycin arm.

Renal adverse events were seen in 2.5% of telavancin patients and 0.5% of vancomycin patients, but few were severe. In patients with a serious renal adverse event, which occurred in less than 1% of patients in both groups, the event had resolved, or was resolving, at the last visit. In both arms of the studies, 12% of patients entered with a creatinine clearance of less than 50 milliliters a minute.

The studies were financed by Theravance, Inc., of San Francisco, which is developing telavancin.