Chinese drugmaker Sinopharm has gained approval to launch clinical trials of a COVID-19 drug based on human immunoglobulin derived from vaccinated people, the company said recently.

The drug is the world's first COVID-19 therapy that uses plasma containing rich amounts of antibodies to fight off the novel coronavirus, and it adds to the company's expanding portfolio of medical products targeting the disease, including four vaccines that have already been rolled out or are being researched.

The experimental medication is being developed by Beijing Tiantan Biological Products, administered by China National Biotech Group, a Sinopharm subsidiary. It obtained clinical trial approval from the National Medical Products Administration on Aug 30.

Zhu Jingjin, a senior official of China National Biotech Group, said the experimental medication uses plasma from healthy people who are fully immunized with inactivated vaccines, and contains high levels of neutralizing antibodies.

"The drug can have therapeutic effects on people with moderate or severe illnesses," he told China Central Television during an exhibition in Beijing on Saturday.

Zhu added that the drug has completed preclinical studies and animals tests, and has demonstrated marked efficacy in relieving the symptoms and damage caused by the virus in animal tests.

The new drug is based on a promising treatment used during the COVID-19 epidemic, according to the company. At the height of the domestic outbreak early last year, China began infusing patients with convalescent plasma of people who had recovered from the disease.

The National Health Commission said in February last year that the therapy had yielded positive outcomes in safety and efficacy, and it was officially added to a national diagnosis and treatment guideline the same month.

As the virus has been brought under control in China, leading to a sharp drop in patients able to donate the convalescent blood needed to make the medication, increasing numbers of fully vaccinated people in the country have helped guarantee supplies of raw materials, according to Chen Kun, another senior official at China National Biotech Group.

In an interview with Global Times, Chen said the drug has been given to patients during recent sporadic local outbreaks and has also shown efficacy against emerging variants. However, he also noted that when and whether the drug can be approved for market use remains uncertain.

"The international norm is that the first stage of clinical trials for a new drug might take seven to eight years, and it is hard to discern how long it will take for us to complete all three phases of human trials," he said, adding that the accelerated approval procedures for COVID-19 vaccines had raised some hope.