Like the drug made by Switzerland-based Roche, the new medicine is a neuraminidase inhibitor which inhibits an enzyme called neuraminidase and prevents the virus from leaving the cell and spreading to others.

But its molecule structure is different from Tamiflu's.

"We have completed clinical experiments, and find it is more effective on humans than Tamiflu," said Li Song, a leading scientist of a research group of the Academy of Military Medical Sciences.

The cost is only a quarter to a third of Tamiflu that sells at 29.8 yuan (US$3.73) for each capsule in China, he told a high-profile forum on prevention and control of avian influenza yesterday.

He added the new medicine would be produced by domestic companies and stockpiled only for pandemic use against the deadly strain of the H5N1 bird flu virus.

Tamiflu is the only drug acknowledged worldwide as effective against human infections and is being stockpiled by governments for possible use in a pandemic.

On December 12, Shanghai Pharmaceutical Group (SPG) became the first in Asia to secure a license from Roche for the production of a generic variety of Tamiflu.

The licence allows SPG to produce and sell the drug, known generically as oseltamivir, on the Chinese mainland.

Li's team is also working on an injection which can be used for emergency treatment.

"Patients in a critical condition can hardly take oral medication. Also, injections are more efficacious than oral medication like Tamiflu or the new drug," Li said.

Li said all medicines for human infections are basically best for prevention rather than treatment, because "bird flu knocks men off so quickly."

For example, Tamiflu is effective only if taken within 48 hours after contracting the virus.

The fatality rate for human infections is about half and patients usually die within a week of being infected.

Amantadine and rimantadine are also used in China against human infections.

While neither is recommended any longer by the World Health Organization as the virus has developed resistance in some countries, "they are still effective in China," said Chen Hualan, the country's top veterinarian from the Harbin Veterinary Research Institute, the only one involved in bird flu research.

In the past week, China has announced several breakthroughs in the battle against bird flu.

On Saturday, scientists at Chen's laboratory announced the development of the world's first live vaccine against bird flu and Newcastle disease, two killer infections for poultry.

Last week, clinical trials began for a human vaccine against H5N1 and Beijing-based Sinovac Biotech Co Ltd, which developed the vaccine, said the exercise may last a year.

Yin Weidong, managing director of Sinovac, said China would need 200 million doses of the vaccine.

"It is better to build up the production capacity of seasonal vaccines, so that when a pandemic occurs, companies can quickly start mass production," said Yin.

The country has reported six human infections of bird flu of which two died by yesterday and 31 major outbreaks among poultry.

The disease has cost the domestic poultry industry losses of more than 60 billion yuan (US$7.5 billion) between October and December, according to official figures.

But thanks to China's aggressive preventive measures, 30 out of 31 outbreak sites have been lifted out of epidemic isolation. By December 14, China had not reported a new case within half a month.

Source: China Daily