BEIJING • Two Covid-19 antibody drugs developed in China have yielded promising results in clinical trials, researchers say.

A cocktail therapy of monoclonal antibodies BRII-196 and BRII-198 has shown an efficacy rate of 78 per cent in cutting Covid-19 hospitalisations and deaths among high-risk groups in late-stage clinical trials, Professor Zhang Linqi of Tsinghua University's School of Medicine said on Sunday.

The treatment was jointly developed by his team at Tsinghua, the Third People's Hospital in Shenzhen, Guangdong province, as well as biotech company Brii Biosciences.

Prof Zhang said researchers first isolated several hundred monoclonal antibodies from infected patients and found that dozens demonstrated potent and wide-spectrum ability to neutralise the virus.

They then identified a pair of antibodies that, when used in conjunction, could exert antiviral effects while curbing the emergence of new mutations.

Prof Zhang said the randomised, double-blind and placebo-controlled trial is being guided by the National Institutes of Health in the United States.

"The (efficacy) rate is based on studies covering four continents, six countries and 111 clinical research facilities. The result is very promising," he said, adding that the trial involved participants of different ethnicities and was performed when multiple emerging variants were circulating.

The team applied to the US Food and Drug Administration for emergency-use approval last month, and has also applied to China's top drug regulator for conditional market approval.

Another domestically developed treatment, based on the potent neutralising antibody DXP-604, has been authorised for compassionate use. The drug - developed by Professor Sunney Xie, director of the Beijing Advanced Innovation Centre for Genomics at Peking University, and his team - has been administered to 35 patients who were mild or moderate Covid-19 cases.

After receiving the drug, it took an average of 15 days for the patients to return negative results in nucleic acid tests and qualify for discharge - much shorter than the average hospital stay of 26 days for patients infected with the Delta variant.

The drug also reduced viral load in patients, relieved inflammation and symptoms in respiratory tracts, boosted antibodies, and helped them regain their senses of smell and taste, Prof Xie said.

However, he qualified that the compassionate-use programme was not the same as a strictly controlled trial, and that more studies are under way to test its efficacy.

CHINA DAILY/ASIA NEWS NETWORK