A traditional Chinese medicine preparation used to treat cancer and boost patients' immunity has been given the go-ahead for a third phase of clinical trials in the US, the last major hurdle for those wishing to launch new drugs in the US market.

The drug, known as Kanglaite Injection, contains anticancer compounds extracted from the seed of coix, a grasslike relative of maize, and has been approved and used as a cancer treatment in China since 1995.

It has been used by more than 200,000 patients and is among the best-selling cancer treatments in the country.

Its inventor, Li Dapeng, has been seeking registration for the drug in the United States. The US Food and Drug Administration gave the go-ahead for clinical trials in 2001. Kangalite is the first TCM injection treatment to undergo the FDA approval process.

"After promising results from the Phase 2 clinical trials, they are permitting us to move on to the third and final phase, where a larger number of volunteer cancer patients will be involved," Li said. "If everything goes smoothly, KLT will hit the US market in three years."

In the second phase of trials, the natural herbal remedy exceeded the success rate of Western cancer treatments, prolonging patients' lives by 1.9 months with fewer side effects.

Li described the US approval procedure as long and costly, but said it would be worth the effort if it helps to bring TCM to patients worldwide. It has taken 16 years and the expenditure of millions of yuan to reach the phase three clinical trials stage.

Li is an academic at the Chinese Academy of Engineering and a researcher at Zhejiang Chinese Medical University.

Yu Wenming, deputy director of the State Administration of TCM, said the government will encourage the spread of more TCM products and services abroad to improve people's health worldwide.

TCM remedies that have already been recognized in the West include the asthma treatment Mahuang, also known as Ephedra sinica, and Qinghao, or Artemisia annua, used to treat malaria.

It is difficult to get approval in the West for TCM treatments because of differences in standards, according to TCM expert Zhang Boli of the academy.

"TCM has to learn their rules to become globalized, as people overseas also need this time-honored form of medicine," he said.

"TCM has an efficacy proven by time and experience, while the effectiveness of Western medicine is largely lab and evidence based."

Zhang called for more government support for Chinese TCM producers.