Tigecycline approved

July 2005

The FDA has approved tigecycline (Tygacil, Wyeth), a new IV antibiotic for methicillin-resistant Staphylococcus aureus (MRSA).

Tigecycline is approved for treatment of complicated skin and skin structure infections (SSSIs) and complicated intra-abdominal infections (IAIs) in adults.

“The spectrum of the drug is quite broad, so it can address infections due to a variety of organisms and not just Staphylococcus aureus,” said George H. Talbot, MD, member of the IDSA Antimicrobial Availability Task Force who has done consulting work for Wyeth. “It’s a new class, and therefore it’s active against some bugs that other drugs are not active against so that’s a good thing as well.”

Tigecycline is approved for adults with complicated SSSI caused by MRSA and methicillin-susceptible S. aureus, Escherichia coli, Enterococcus faecalis (vancomycin-susceptible isolates only), Streptococcus agalactiae and the Streptococcus anginosus group.

It is also approved for adults with complicated IAIs caused by Citrobacter freundii, Enterobacter cloacae, Enterococcus faecalis (vancomycin-susceptible isolates only), E. coli, Klebsiella oxytoca, K. pneumoniae, S. aureus (methicillin-susceptible isolates only), S. anginosus group (includes S. anginosus, S. intermedius and S. constellatus), Bacteroides fragilis, B. thetaiotaomicron, B. uniformis, B. vulgatus, Clostridium perfringens and Peptostreptococcus micros.

Tigecycline is contraindicated in patients with known hypersensitivity to tigecycline and should be administered with caution to patients with a known hypersensitivity to the tetracycline class of antibiotics.

In clinical trials, empiric monotherapy with tigecycline provided a comparable clinical cure rate in complicated SSSI to vancomycin and aztreonam (Azactam, Bristol-Myers Squibb), a combination treatment regimen. Empiric monotherapy with tigecycline also provided a clinical cure rate comparable to imipenem/cilastatin (Primaxin, Merck), an empiric treatment for complicated IAI. The overall discontinuation rate for tigecycline (5%) was comparable to that of vancomycin and aztreonam (5.3%) and imipenem/cilastatin (4.4%).

Nausea and vomiting were the most common adverse events during clinical trials.

Wyeth said in its press release that it now awaits decisions on approval of the new antibiotic from other regulatory bodies from countries around the world, including Brazil, Canada, Colombia, Mexico, Switzerland, Taiwan and Venezuela. The company anticipates that the drug will soon be available to hospitals in the United States.

Antimicrobial progress slow

Wyeth’s new antibiotic is a welcome addition to the formulary, but more antimicrobials are still needed, experts said.

IDSA released its report, “Bad Bugs, No Drugs: As Antibiotic Discovery Stagnates … A Public Health Crisis Brews,” last summer, and it explains the resistance problem and proposes a range of specific, innovative policy and administrative measures designed to head-off the impending health crisis.

The report includes recommendations for Congress, the FDA and the National Institute of Allergy and Infectious Diseases. These recommendations will assist various CDC health programs.