[Ip-health] Second flu drug needed 'to avert catastrophe'

[Ira Glazer]

http://news.independent.co.uk/uk/health_medical/article2001505.ece

By Steve Connor, Science Editor
Published: 21 November 2006

A global outbreak of a highly lethal strain of influenza threatens to
engulf Britain if the Government does not change its policy on how to
deal with such a pandemic.

An influential group of scientists has warned the government to
stockpile a second antiviral drug to fight a global influenza epidemic
because of the threat posed by a drug-resistant form of pandemic flu.

They believe that relying on a stockpile of the antiviral Tamiflu could
prove catastrophic if a pandemic strain of the influenza virus develops
resistance to the drug, as indicated by recent studies on the H5N1
strain of avian flu.

The H5N1 virus has spread to many populations of domestic and wild birds
and has crossed into the human population several times, infected 258
people worldwide, and killed 153. Scientists fear that if H5N1 mutates
to make it easier to spread from person to person, it could cause a
global epidemic of highly lethal influenza, which would be made far
worse if the virus is also drug-resistant.

The report by scientists drawn from the Royal Society and the Academy of
Medical Sciences warned that Tamiflu stocks need to be bolstered with a
supply of Relenza, the second antiviral, in case drug resistance develops.

Professor Sir John Skehel, a leading expert on influenza who chaired the
scientific panel, said: "New evidence that H5N1 can develop resistance
to Tamiflu indicates a combination of antivirals should be stockpiled by
the UK. The Government has 14.5 million courses of Tamiflu to cover
about a quarter of the population but the scientific panel pointed out
that H5N1 has already developed resistance to the drug.

In one study, for instance, two out of eight patients in Vietnam who
became infected with H5N1 developed drug resistance to Tamiflu. Both died.

"The Government was right to order Tamiflu in early 2005," Sir John
said. "But we are concerned that it is not updating its plans as what we
know about influenza changes."

Professor Neil Ferguson of Imperial College London, a member of the
panel, said the "nightmare scenario" was that as Tamiflu was used to
treat patients with pandemic flu, a drug-resistant strain emerged to
become the dominant form of virus. "This is why we need to have a
back-up plan," Professor Ferguson said.

Tamiflu, which is made by Roche, and Relenza, made by GlaxoSmithKline,
are neuraminidase inhib-itors - they block a key viral protein - but
they work in different ways.

Tamiflu comes in tablets while Relenza is taken with an inhaler. Sir
John added: "If the virus that comes along was resistant to Tamiflu and
not to Relenza, then we really have to have a stockpile of Relenza as well."

The panel of scientists also recommended that the Government should
appoint a "influenza tsar" to take charge of giving high-level,
independent advice to the Cabinet's ministerial committee on influenza.
Sir John said: "You would look for the best possible person you could
find. This specialist would sit alongside the Government's chief medical
officer and chief scientific adviser to complement their roles and
contribute relevant expertise."

"The UK is recognised as one of the most prepared countries in the
world. However, research in this area must continue and up-to-date
scientific information should be central to the Government's
decision-making process," he said.

* Fighting the virus *

* TAMIFLU

Also known as oseltamivir. Works by blocking neuraminidase, a protein
that allows the flu virus to spread. Made by the Swiss company Roche and
comes in tablets, pictured. Has been widely used in south-east Asia to
treat the H5N1 strain of avian flu, which has killed about half of the
people it is known to have infected.

* RELENZA

Also known as zanamivir. Works by inhibiting neuraminidase, so
preventing the spread of the virus within the body. It is made by
GlaxoSmithKline and is administered through an inhaler rather than
orally. Like Tamiflu, Relenza works best when given to a patient within
24 hours of the first symptoms appearing.