Amid fears of a global flu pandemic (search), production is being stepped up to stockpile the only drug that may be able to treat the illness, but the 12 months it takes to make a dose means governments may have to wait for new orders, drugmaker Roche Holding AG (search) said.

Health experts have been pinning their hopes on the antiviral Tamiflu (search), in case the bird flu spreading across Asia and into Europe mutates so that it could pass easily between people.

"We asked governments several years ago to make Tamiflu orders for pandemic purposes well in advance," Roche spokesman Alexander Klauser told The Associated Press. "We explained the procedure to them, how it works and that we had to start production well in advance or we wouldn't be able to produce Tamiflu in the required amounts on time."

U.N. Secretary-General Kofi Annan (search) said last week that usual patent rules may have to be suspended if there is an outbreak of the disease so that other companies could jump in and make the medicine.

Switzerland-based Roche, the sole manufacturer, said there was no question of relinquishing the patent, which is protected until 2016. Although the drug's effectiveness against bird flu has yet to be proven, U.N. health officials say people who have been in contact with the disease and then taken Tamiflu within 48 hours have not developed symptoms.

So far, nearly all the 100-plus people who have caught bird flu got it directly from birds. More than 60 people have died, but the virus has not been effective at spreading between people.

Roche said there are 10 complex steps to make Tamiflu and it would be unrealistic to outsource all the work, because outside companies would need up to three years to set up production as well as gain the capacity and know-how.

"We are not planning on getting another company to make Tamiflu," said Klauser, dismissing reports the company was ready to discuss allowing other companies to produce the drug.

He said the company already outsources three of its 10 production steps.

Roche said it is continuing to seek other companies to help speed up the production but insisted it has always sought out possible new partners and this was simply brought on by the increase in demand.

"Roche is doing everything it can to speed up production," said Klauser, confirming Roche will have boosted production up to tenfold by mid-2006 from 2003. "We are seeking to further collaborate with companies if they show competency in key specialized areas."

A full five-day treatment of 10 capsules of Tamiflu costs about 86.50 Swiss francs ($76) in Switzerland and up to $86.50 in the United States.

Despite the price, individuals in some countries have been rushing to buy the drug following reports of bird flu cases in Turkey and Romania, health officials said, and pharmacies in some areas of France and Switzerland are out of stock.

Health authorities stressed that Tamiflu should only be taken under doctor's supervision because overuse could enable the virus to become resistant to the drug.

It is not certain Tamiflu would be effective if the current bird flu strain mutates into a form that could be spread between humans.

"We don't know when or if it will mutate," said Dick Thompson, a spokesman with the World Health Organization. "Or if Tamiflu will still be effective. Maybe it will require taking Tamiflu and another antiviral. We just don't know."

So far no vaccine is available to immunize people from bird flu, but some health authorities have recommended people get ordinary flu shots because it might help prevent bird flu from combining with easily spread human flu.

Thompson said he was unable to say whether supplies of vaccine were sufficient to treat increased demand in Europe.

Tamiflu is made from an acid produced from the Chinese star anise plant, which is in limited supply because it is grown in only four provinces in China and is harvested between March and May.

However, in the past year, Roche discovered a way to make the acid, called Shikimic acid, without the plant.

Until recently, in most markets, sales of Roche's Tamiflu, launched in 1999, were well below the company's expectations. But that changed last year, when WHO recommended governments stockpile antiviral drugs, such as Tamiflu.

Consequently, sales of Tamiflu from January to June 30, 2005, were nearly double the number in 2004. Experts expect revenue from the drug to reach at least 800 million Swiss francs ($620 million) this year.

Roche has donated 3 million doses of Tamiflu to the WHO, which has asked Roche to increase production of Tamiflu quickly, including by working with other companies.