Race is on to make bird flu drugs

The threat posed by bird flu may just have receded a little. The Indian company Cipla says it will begin marketing a generic version of the antiviral drug oseltamivir, better known as Tamiflu, by December and will be able to make a million 10-capsule courses of treatment per month by next July. The drug is one of the few that can block replication of the H5N1 virus, potentially preventing the illness from becoming fatal.

The move had been opposed by Swiss pharmaceutical giant Roche, which holds the patent on Tamiflu. But this week, in a dramatic turnaround, Roche said it would not oppose companies that want to strike a licensing deal.If a pandemic of H5N1 flu arrives soon, antivirals are the best hope of saving lives. A potential vaccine against H5N1 has been available since early 2004, but trials in humans are only now beginning.So governments are looking to stockpile antiviral drugs. One class of these drugs, adamantanes, works against the H5N1 virus strain found last week in Europe. But they have no effect on the strain that has killed at least 60 people in east Asia, and even susceptible strains quickly become resistant. This has led to heavy demand for the second class of drugs, neuraminidase inhibitors, of which Tamiflu is the most widely available.While some strains of H5N1 are resistant even to Tamiflu, they are thought to be too weak to pose a serious threat. But H5N1 is so virulent that the drug may not save the patient. In experiments published in July, the equivalent of the 10-capsule course of treatment used in humans saved only half of infected mice, and even 16 capsules saved only 80 per cent.The main problem, however, is supply. Roche, the only company now making Tamiflu, says it doubled production in 2004, doubled it again this year and will double it again by 2007. Though Roche will not say how much drug that amounts to, its annual report suggests it could be of the order of 40 million courses a year.Even at that rate, it will take Roche more than two years to fulfil the orders it now has. And the drug is expensive. Roche says it “haggled” a favourable price for governments, thought to be around $30 per course. Apart from 3 million courses Roche donated to the World Health Organization, there is almost no Tamiflu in developing countries.Now Cipla, the Indian firm that makes 75 per cent of the AIDS drugs used in Africa, says it can make generic Tamiflu. Thailand is planning to do the same, while Taiwan said last week that only patent restrictions are stopping it.Roche’s about-face is the first major success for generic drug makers under an agreement on access to drugs reached at a World Trade Organization meeting in Doha, Qatar, in 2001. Under this agreement, Cipla could have legally sold Tamiflu in less developed countries, including most of Africa, without Roche’s permission. These countries needn’t recognise patents until 2016.Now it is clear the company will be able to sell the drug in India too. That’s just as well, Cipla managing director Amar Lulla told New Scientist. “If a pandemic comes to India, people will die like flies,” he says. “We have nothing.”(Source: New Scientist: issue 2522, 20 October 2005, page 14.)