But the Swiss company insists that it remains best able to supply global demand as its present capacity of 300 million treatments per year allows it to supply more than the orders it has received for 2006. "As yet, we have not identified anyone who could significantly speed up the agreed delivery timelines for the first half of 2006, but we have been able to identify partners to ensure against breakdowns in supply and partners to broaden geographic coverage," says William M. Burns, head of Roche's pharmaceutical division.

Other companies that are attempting to produce Tamiflu have faced difficulties in sourcing its key raw material, shikimic acid, which is extracted from Chinese star anis and is in short supply. Roche has a process to obtain shikimic acid by fermentation, but it does not say whether it will share the technology with licensees.