The Lancet Publishes The First Ever Phase III Clinical Trial Involving a Neuraminidase Inhibitor
Biota's orally inhaled antiviral drug, zanamivir, shows efficacy and accelerated recovery in treatment of influenza.
11 December 1998
Zanamivir is shown to be effective for the treatment of influenza A and B, according to a paper published today in the prestigious medical journal The Lancet – the first time data from a Phase III clinical trial involving a neuraminidase inhibitor has been published in a peer reviewed journal.
Results of this Phase III treatment trial showed that influenza patients treated with orally inhaled zanamivir:
•Had less severe symptoms throughout the course of their illness;
•Attained relief from the major symptoms of influenza up to 2.5 days earlier than those receiving placebo1 (up to 40% quicker);
•Experienced no more side-effects than those taking placebo;
•Returned to their normal activities 2 days earlier than those taking placebo.
The results also showed that "high risk" patients experienced fewer complications (14% zanamivir vs. 46% placebo) leading to a significant reduction in the associated use of antibiotics.
This trial, recruited 455 patients and was conducted in Australia, New Zealand, and South Africa, during the 1997 winter season in the Southern Hemisphere (321 patients were confirmed with influenza; 67% influenza A and 33% influenza B). Patients were treated with 10mg twice daily of inhaled zanamivir or inhaled placebo, for five days, within 36 hours of the onset of symptoms1. Patients in this double-blind, randomised trial kept a symptom diary card, which they completed four times per day for the five treatment days, and then twice daily for the following nine days.
"The primary endpoint measure of our study was median time to alleviation of clinically significant influenza symptoms," said Professor Chris Silagy, Flinders Medical Centre, South Australia, and the trial's lead investigator. "Zanamivir showed clinically and statistically significant benefit in terms of this endpoint." The study also showed that patients at risk of developing complications as a result of influenza infection experienced a 70% reduction in complications when given zanamivir (p=0.004), and a 61% reduction in associated antibiotic use (p=0.025)1.
"Influenza is a serious respiratory tract infection, which merits intervention with antiviral therapy," said Professor Silagy. "It can strike anyone, knocking an otherwise healthy person off their feet. In high risk patients, such as the elderly or people with other underlying diseases, influenza can be fatal." He added that: "By inhaling zanamivir, the drug is delivered direct to the airways, which is the site of infection and where the virus is replicating."
Zanamivir is the first orally inhaled drug in a new generation of specific treatments against the influenza virus, known as neuraminidase inhibitors, which work by interfering with the lifecycle of the influenza virus. It blocks the neuraminidase enzyme on the surface of the virus, thus preventing its release from the cell and inhibiting it from spreading to neighbouring cells within the respiratory tract.
Zanamivir has been developed by Glaxo Wellcome under licence from Biota Holdings Limited. This licence gives Glaxo Wellcome the rights to develop and market zanamivir worldwide.
The first application to market the product was made in Australia at the end of March 1998. Regulatory submissions for zanamivir, to be marketed under the trade name Relenza2, have recently been made in the US, Canada and Europe.
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