Food and Drug Administration
U.S. Department of Health and Human Services
Public Health Service 5600 Fishers Lane Rockville, MD 20857
FDA Talk Papers are prepared by the Press Office to guide FDA personnel in responding with consistency and accuracy to questions from the public on subjects of current interest. Talk Papers are subject to change as more information becomes available.
T00-17 Print Media: 301-827-6242 April 18, 2000 Consumer Inquiries: 888-INFO-FDA
Infections due to Enterococcus faecium and MRSA are a particular problem in hospitalized or immunocompromised individuals. These organisms are often resistant to multiple antibiotics. Vancomycin has, for many years, served as the treatment of last resort for these infections. In 1989, the first case of vancomycin-resistant Enterococcus faecium (VREF) was reported in this country. Since then, there has been a rapid increase in the incidence of VREF infections, as well as a dramatic increase in the incidence of MRSA infections. There have been limited therapeutic options available for patients with these infections.
Zyvox is the first in a new class of synthetic drugs -- the oxazolidinone class -- approved for use in the United States and the world. It is also the first drug in over 40 years to be introduced into the US market for treatment of MRSA infections.
Zyvox's approval was supported by controlled clinical trials that enrolled more than 4000 patients. The approval for VREF infections was based on a dose-comparison study in which 145 patients were treated with Zyvox (600 mg or 200 mg) every 12 hours for VREF infection. Types of VREF infections studied included complicated intra-abdominal infections, complicated skin and skin structure infections, urinary tract infections, and bacteremia of unknown origin. The cure rate for Zyvox was 67 percent in the high-dose arm and 52 percent in the low-dose arm.
Zyvox was also found to be as effective as vancomycin for treatment of hospital-acquired pneumonia, including cases due to MRSA, in a controlled clinical trial involving about 400 patients. The approval for complicated skin and soft tissue infections, including those caused by MRSA, was based on a controlled clinical trial of approximately 800 patients comparing linezolid with oxacillin/dicloxacillin. Additional information on the use of linezolid in the treatment of cases of hospital-acquired pneumonia and skin and skin structure infection caused by MRSA came from a supportive study comparing linezolid to vancomycin.
The most frequently reported side effects attributed to Zyvox in the clinical studies were headache, nausea, diarrhea, and vomiting. The most important laboratory test change was a decrease in platelet counts.
Zyvox may interact with certain other drugs, including over-the-counter cold remedies that contain pseudoephedrine or phenylpropanolamine, and cause an increase in blood pressure. Patients receiving Zyvox should inform their physicians if they are taking such medications.
Pharmacia and Upjohn, the drug's manufacturer, anticipates that therapy with Zyvox will be initiated principally in the hospital or institutional care setting. Due to concerns about inappropriate use of antibiotics leading to an increase in resistant organisms, prescribers should carefully consider alternatives before initiating treatment with Zyvox in the outpatient setting.
FDA's approval follows the recommendations of the Anti-Infective Drugs Advisory Committee. Their recommendation for approval of these indications was based on the results of clinical studies presented at a meeting of the Committee on March 24, 2000.
Pharmacia and Upjohn, based in Kalamazoo, Mich., developed Zyvox and will market it in the United States.
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