(Yicai Global) Sept. 9 -- Shenzhen Kangtai Biological Products, the exclusive Chinese mainland distributor of AstraZeneca’s upcoming Covid-19 vaccine, saw its share price plummet 15 percent as of 2 p.m. this afternoon on the news that the British pharmaceutical giant is to temporarily suspend Phase III clinical trials after a volunteer suffered an adverse reaction.

Kangtai Biological [SHE:300601] plummeted to CNY165.01 (USD24) after crashing as much as 19.6 percent earlier in the day. AstraZeneca [NYSE:AZN] fell by 8 percent to USD50.26 in after-hours trading.

Vaccine maker Kangtai Biological last month reached a deal with AstraZeneca to mass produce its upcoming Covid-19 vaccine in China, with an annual output capacity of at least 100 million doses.

Now Cambridge-based AstraZeneca, which is developing the drug alongside the University of Oxford, has put the brakes on its late stage Phase III trials after a British volunteer developed an unknown, adverse reaction.

The suspension will not influence the partnership between AstraZeneca and Kangtai Biological, the National Business Daily reported today, citing the secretary to the chairman of Kangtai Biological. AstraZeneca is one of the leading developers of Covid-19 vaccines and has the largest scale of clinical trials. It is quite normal for individual cases to emerge, he added.

AstraZeneca is one of the frontrunners in the global race to develop a Covid-19 vaccine and started Phase III clinical trials in July, aiming for it to be one of the first to hit the market.

"As part of the ongoing randomized, controlled global trials of the Oxford coronavirus vaccine, our standard review process was triggered and we voluntarily paused vaccination to allow review of safety data by an independent committee," AstraZeneca said yesterday.

"This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials."

"We are working to expedite the review of the single event to minimize any potential impact on the trial timeline," it added.

Editor: Kim Taylor