AstraZeneca missed a September deadline for its COVID-19 vaccine in the U.K., and it's going to deliver far fewer doses than promised by year-end. But CEO Pascal Soriot says delays in its clinical trial prompted the company to hold off manufacturing.
Instead of 30 million doses of AZD1222, the U.K. will only receive 4 million this year, Vaccine Taskforce Chair Kate Bingham said, as reported by Reuters.
“The predictions that were made in good faith at the time were assuming that absolutely everything would work and that there were no hiccups at all,” Bingham told lawmakers, as quoted by the news service, referring to a supply deal AZ signed with the U.K. government in May.
The hiccup was not caused by AstraZeneca’s inability to produce enough vaccines, but mainly because of a slowdown in the ongoing phase 3 clinical trial, Soriot said Thursday during a call with reporters.
For the phase 3 efficacy clinical trial to read out, enough participants would need to contract the novel coronavirus as they go about their daily lives to allow researchers to assess the AZ candidate’s ability to protect against infection compared with a dummy shot.
When AstraZeneca signed the U.K. contract, infection rates were on the rise in the general public. But the number of incidents dropped during the summer, slowing the trial’s progress, Soriot explained. Now, with cases ticking upward again, the company expects to have data available by year-end, he said.
Besides slower infection incidents, the AZ shot’s phase 3 was temporarily paused for more than a month after a trial participant developed a serious neurological illness. The trial got the go-ahead to resume in the U.S. in late October.
Because of the trial delays, AZ’s projected timeline for a vaccine authorization was also extended. To ensure the final product enjoys maximum shelf life as doses are rolled out in mass vaccination campaigns, AZ decided to postpone its delivery to governments, Soriot said.
In fact, AZ has already produced a bulk vaccine that’s kept at freezing temperatures. The shelf life clock starts ticking once that frozen drug substance moves into the formulation phase of production, Pam Cheng, the company's head of operations and IT, said.
The company is ready to provide finished commercial products, Cheng said. “However, we really must be thoughtful on how much we progress to the final product stage,” she said. “We want to have maximum shelf life upon regulatory approval around the world.”
At this point, it’s better to keep the vaccine in that frozen state because it can be stored for longer. After getting positive data from clinical trials, AZ can start “massively filling vials, and we’ll be ready to supply hundreds of millions of doses starting January next year,” Soriot told reporters.
When that day comes, AZ can supply the doses on a rolling basis on a delivery schedule that matches the government’s plan for the pace of vaccination, he added.
The British pharma has built a global supply chain able to churn out 3 billion doses of the vaccine. A few weeks ago, the company hit its process validation milestone, which means it has established quality assurance, the final step before commercial manufacturing, Soriot said.
AZ has pledged not to profit off the COVID-19 shot during the pandemic. Besides including the manufacturing costs in that calculation, the company is recording costs of more than $1 billion from clinical trials and other activities. To ensure that it’s offsetting those expenses, AZ’s adding an amount equivalent to a maximum of 20% of the manufacturing cost to the vaccine’s price, Soriot said.
On top of the 100 million doses it has promised the U.K. government, AZ has a contract to provide 300 million doses to the U.S. and another with the EU for 400 million doses. In Japan, the company has agreed to deliver 120 million doses. In China, the vaccine will be offered by local firm BioKangtai, which will reserve enough capacity to make at least 100 million doses by the end of 2020.