A vial of AstraZeneca vaccine.
Igor Petyx | KONTROLAB | LightRocket via Getty Images
Healthcare analysts welcomed AstraZeneca’s findings on the highly anticipated results of a late-stage American trial for its Covid-19 vaccine.
The trial of more than 30,000 participants in the US, Peru, and Chile found that the vaccine was 79% overall effective in preventing symptomatic Covid and 100% effective in preventing serious illness and hospitalizations.
Efficacy was consistent across all ages and ethnic groups, with 80% efficacy in participants aged 65 years or older. The vaccine, known as AZD1222 and developed with the University of Oxford, was well tolerated and the independent data safety monitoring board did not identify safety concerns related to the vaccine, the company said Monday.
The data exceeded expectations
In a research note, Jefferies healthcare analyst Peter Welford called the data “surprisingly positive.”
Adam Barker, Healthcare Analyst at Shore Capital, said: “This is arguably the first trial for AZD1222 that has shown convincing efficacy in people 65 and older.”
This is important because there were doubts about efficacy in this age group. Previous studies were hampered by fewer elderly participants. In this trial, 20% of the participants were 65 years of age or older and 60% had comorbidities that put them at higher risk of developing serious disease.
Data from Monday’s trial confirmed the safety profile of the vaccine. Barker said that because the data comes from a single trial using a single-dose regimen, it eliminates the complications of data interpretation that have been seen in the past with the AstraZeneca-Oxford vaccine.
Barker added that the lack of evidence of blood clots in the study was also reassuring given recent concerns. “However, these data do not surprise us, given that the evidence for a link between the vaccine and blood clots was already quite weak.”
AstraZeneca said it will continue to analyze the data and prepare for the main analysis that will be sent to the US Food and Drug Administration for emergency use authorization in the coming weeks. The vaccine has already received a conditional marketing authorization or emergency use in more than 70 countries on six continents.
Dosing regimen is a key question for the FDA
“I don’t see why the regulator wouldn’t approve it,” Barker wrote, but cautioned that detailed data was still pending.
A key question for the FDA will be which dosage regimen it will support if it ultimately approves the vaccine for emergency use.
“This trial is based on dosing 4 weeks apart, but we know that efficacy may be greater if given with a longer interval (up to 12 weeks) and countries like the UK have used this’ higher duration between doses’ to vaccinate people more quickly, “Barker said.
So the question for the FDA is whether they recommend giving the two doses four weeks apart, given that is what was tested in the US trial, or include data from the UK and elsewhere suggesting that one longer duration is appropriate.
Welford also noted the suboptimal dosing regimen used in this trial. “The trial evaluated the 4-week dosing schedule, but we have evidence to suggest that the vaccine works better with a longer dosing interval,” he said.
“The primary analysis of phase III clinical trials in the UK, Brazil and South Africa showed an efficacy of 62% when the vaccine was given in an interval of 4 to 12 weeks, but the efficacy increased to 82% when the interval was extended. to 12 weeks. “
Beyond dosage, analysts are also looking for additional details on how the vaccine protects against different variants. This is expected to be included in the data packet sent to the FDA.
When it comes to comparing current efficacy data with that of some of the other vaccine manufacturers, Welford cautioned that since the initial vaccine readings from Pfizer and Moderna, Covid-19 variants have become increasingly common, therefore, the efficacy data are not directly comparable between the different vaccines.
Barker added that the trial results gave the vaccine important validation. “Given its cost and ease of storage and distribution, AZD1222 was once described as a ‘vaccine for the world.’ In our opinion, this is a fair label,” he wrote. “Data like this reported today that more conclusively demonstrate the efficacy and safety of AZD1222 is certainly something to celebrate.”
AstraZeneca is committed to distributing the vaccine on a non-profit basis for the duration of the pandemic. The company’s shares traded 2% higher in London on Monday.