KEY POINTS:
A new influenza drug being trialled in New Zealand has the potential to save millions of lives during a worldwide pandemic and could be as effective as - or more effective than - Tamiflu in combating a outbreak of avian flu, experts believe.
Antiviral drug Peramivir, developed by US pharmaceutical company BioCryst and sponsored by the US government, is currently being trialled on influenza-infected patients at seven New Zealand "study centres". A single injection of the drug, which like Tamiflu is a neuraminidase inhibitor, stunts the growth of the enzyme neuraminidase needed for the flu virus to flourish in the body.
Greenhithe Medical Centre, in Auckland's northwest, is one of the seven centres seeking flu patients to take part in the trial, which is predicted to run in New Zealand until next month at least.
Trial head at Greenhithe, Dr Nick Gailer, told the Herald on Sunday that the drug trial had massive implications for the treatment of all strains of potentially debilitating influenza, as well as avian flu.
Ultimately, it could see an antiviral injection enter the market which decreased the severity of flu symptoms and the length of time people were sick. If it was proved that it eradicated the disease from the nose more quickly, that would also reduce the amount of time the flu sufferer was contagious.
Gailer said those who had been suffering from flu symptoms for no longer than 48 hours and who were found to definitely have the influenza virus, rather than just a cold were eligible to take part in the trial. One third of patients would be given a placebo, but all patients would receive their initial visit free and would be given paracetamol and lozenges; in return, they would be required to keep a diary of their experience.
Other centres running the trial in New Zealand are in Otara, Dunedin, Hamilton, Rotorua, Taupo and Christchurch.
BioCryst, who was this year awarded a US$100 million ($130 million) contract to develop the drug by the US government, is testing Peramivir in Australia, South Africa and the Northern Hemisphere.
Virologist Dr Lance Jennings told the Herald on Sunday it was always helpful to have more than one anti-viral medication to combat a virus, as the bugs can become resistant to medications over time. Peramivir's chemical structure is substantially different from those of Relenza and Tamiflu. A US study in 2001 also found the drug was more potent than others against a range of avian influenza strains.
A separate hospital-based trial of the drug is also running, involving three New Zealand hospitals.
Gailer said it was too early to put a cost on the drug. Tamiflu, which is taken orally over five days, costs about $80 for the course.
How does it work?
The enzyme neuraminidase is responsible for the release of particles from 'flu-infected cells. These particles then spread the disease and may also assist in spreading the virus through mucus, allowing it to escape the host through a sneeze or a cough, and infect others. It is believed that Peramivir can stop the spread of the disease - an important advance in the management of influenza. Peramivir may also be effective in preventing 'flu, regardless of the particular strain or mutation.
Flu stats
The dreaded flu has been keeping a relatively low profile so far this season, statistics show. But experts say they can never predict when a big outbreak will occur, and there is often a nasty, late-season spike of infections in August and September. There have been four strains of the virus lurking around this year - two A and two B strains, virologist and National Influenza Strategy Group (NISG) spokesman Dr Lance Jennings, said. Weekly reports of GP consultations from 80 surgeries showed levels of 'flu to be "normal" so far this season, he said.
