Barbara L. Jones

October 30, 2008

October 30, 2008 (Washington, DC) — Peramivir, a novel neuraminidase inhibitor, was effective for the treatment of seasonal acute influenza after a single-dose intravenous infusion, according to results from a double-blind placebo-controlled phase 2 Japanese study.

This late-breaking abstract was presented here at the 48th Annual ICAAC/IDSA 46th Annual Meeting, a joint meeting of the American Society for Microbiology and the Infectious Diseases Society of America.

Emphasizing the real-world benefits of this agent, lead author Shigeru Kohno, MD, PhD, dean of the Nagasaki University School of Medicine, in Japan, said: "If you ask patients to take a medicine for 4 or 5 days or more, they may forget. One shot is perfect."

Patients aged 20 to 64 years who had been diagnosed with influenza using a rapid antigen test were recruited within 48 hours of the onset of flu symptoms. Of 300 patients, 296 in the intent-to-treat population were randomized to peramivir 600 mg (n = 97), peramivir 300 mg (n = 99), or placebo (n = 100).

Seven typical influenza symptoms were assessed by the patients for 14 days: cough, sore throat, headache, nasal congestion, fever or chills, aches and pains in muscles and joints, and fatigue. Patients graded their symptoms on a scale of 0 (absent) to 4 (severe). Patients also reported their daily body temperature for the same time period. The investigators determined virus titer using nasal and pharyngeal swabs.

Peramivir significantly reduced the time to alleviation of symptoms, the primary end point, at both doses — 600 mg (hazard ratio [HR], 0.666) and 300 mg (HR, 0.681) — compared with placebo (adjusted = .0046 for both comparisons).

A composite symptom score was significantly improved for both peramivir 300 mg and 600 mg, compared with placebo, as early as 24 hours after treatment (P = .0032 and = .0109, respectively).

In addition, a significant change in virus titer from baseline to 2 days after the infusion favored 600-mg peramivir over placebo (= .0027).

No serious adverse events were reported. Peramivir was associated with an adverse-event profile that was similar to that of placebo.

Ann Falsey, MD, associate professor of medicine at the University of Rochester, in New York, and a researcher in the epidemiology and immunology of influenza, who was not involved in this study, highlighted another important benefit of a nonoral medication. "I think what this offers in addition to the usual antibiotic is an alternative to patients for whom oral therapy is a problem.

"It is also important to think ahead to pandemic flu," Dr. Falsey said. "Those patients might be extremely sick, and their digestive tracts may not be working. They may be in intensive care. So I think it's important to have an armamentarium of drugs available in intravenous form. It looks like this drug was similar to Tamiflu [oseltamivir phosphate] in its effectiveness."

The study was funded by BioCryst Pharmaceuticals, codeveloper of peramivir. Dr. Kohno is a consultant for Shionogi & Co, Ltd, which is in partnership with BioCryst. Dr. Falsey has disclosed no relevant financial relationships.

48th Annual ICAAC/IDSA 46th Annual Meeting: A Joint Meeting of the American Society for Microbiology and the Infectious Diseases Society of America: Abstract V-4154a. Presented October 28, 2008.


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