ousia's update: half year results, page-16

(Sir) Lunchalot,

I readily accept that the Bird Flu virus can attack other organs in the human body. But in the event of a much feared pandemic, this form of influenza will be passed between humans by the inhalation of shed virus, just as we catch normal flu. The person beside you sneezes or coughs and you breathe in the virus.

So given that its critical to employ either Relenza or Tamiflu early in the onset of the disease, the battle field is most likely to be in the airways or lung. If it gets beyond that stage, I think the person is going to be very sick indeed.

Now the question of drug resistance is extremely interesting. In my lay man's view, resistance is achieved by the virus subtly changing its profile through countless divisions and multiplications and eventually reaching a stage where it prevents the drug from working as effectively as was originally intended. Thereafter natural selection ensures that partial resistance becomes full resistance and the drug is ultimately defeated.

With Tamiflu, as I understand it,the virus enters a host cell, divides but is prevented from leaving the host cell by Tamiflu's action on it. Now because division is not prevented it is conceiveable that the virus will be able to change over time to reduce Tamiflu's effectiveness. Once a Tamiflu treated virus has managed to escape a host cell, natural selection will see the virus subtly mutating in that direction.

But if Relenza prevents the influenza virus from dividing then it is difficult to see how the virus can mutate, in its interaction with Relenza.

I would really welcome an informed view from Biota on how Relenza interacts with the Influenza virus and whether resistance is likely to be more likely, less likely or the same as other anti virals such as Tamiflu.

Whilst I may think that resistance should be less likely with Relenza than Tamiflu, it would seem incredibly unlilely that such a strong advantage would be overlooked or dismissed when the balance of the recent US order was settled upon.