AstraZeneca Shares Fall After Putting Vaccine Trial on Hold

The Phase 3 trial just started in August and is being paused because of a serious adverse reaction in a participant.


AstraZeneca shares dropped more than 6 percent during after-hours trading on Tuesday evening. The fall in shares occurred after the company announced that it was pausing it’s late-stage coronavirus vaccine trial because of safety concerns.

The pharmaceutical company released a statement saying, “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. In large trials, illnesses will happen by chance but must be independently reviewed to check this carefully. We are committed to the safety of our participants and the highest standards of conduct in our trials.”

The company said it will work towards minimizing the impact on the timeline of the trial. AstraZeneca published data in July showing that its vaccine showed a promising immune response in its early-stage trials. At that time, the vaccine was tolerated well by its trial participants and had no serious adverse reactions. Common side effects were headache, fatigue, chills, muscle aches, fever, and pain at the injection site.

But an adverse reaction of a serious nature during the late-stage trial is the cause of the current hold on the trial. The reported illness occurred in the U.K. and the length of the hold is unknown.

AstraZeneca began the Phase 3 trial in late August. The company is one of three that’s in late-stage testing for a vaccine candidate. Moderna and Pfizer are the other two drug companies and those companies began their late-stage trials in July.

On May 21, the U.S. government said it would pay AstraZeneca a sum of up to $1.2 billion for the experimental vaccine, which was developed at the University of Oxford. In exchange, it’s expected that the U.S. will receive a minimum of 300 million vaccine doses.

The vaccine is called AZD1222 and is made from genetic components of the coronavirus combined with an altered adenovirus. The same technology used to create the experimental Ebola vaccine in 2019 for the Republic of Congo was used.


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