AZ mulls trial of new COVID-19 vaccine dose as UK regulator begins review

AstraZeneca is to run an additional global trial to test its COVID-19 vaccine at a lower dosage, as the UK regulator begins to review trial data.

The shot, known as AZD-1222, developed in partnership with Oxford University, has dominated the pharma news agenda this week after it hit efficacy targets but appeared short of rivals from Pfizer and BioNTech.

With an overall efficacy of 72%, below the 95% seen with rivals, AZ’s vaccine would have been even weaker had it not been for a stronger potency seen in patients accidentally treated with a half dose followed by a full dose.

Now CEO Pascal Soriot wants to conduct a new test to confirm the 90% efficacy rate of the lower dose regimen, which was stumbled upon because of a manufacturing mistake.

The companies did not disclose the error at the time and there are concerns over their transparency, Bloomberg news reported.

Soriot told Bloomberg: “Now that we’ve found what looks like a better efficacy we have to validate this, so we need to do an additional study."

This will likely be another international study but could be faster as it will require fewer patients due to the higher efficacy seen with the revised dosing regimen.

The additional trial is unlikely to hold up regulatory approvals in the UK and EU, according to Soriot.

Health secretary Matt Hancock has asked the UK’s regulator the Medicines and Healthcare products Regulatory Agency (MHRA) to begin its review of the vaccine.

The Department of Health and Social Care said the UK could be one of the first in the world to receive the vaccine if authorised.

AZ is set to have up to 4 million doses ready for the UK by the end of the year and 40 million by the end of March.

The government also has pre-ordered 40 million doses of the Pfizer/BioNTech vaccine, which could be more than 90% effective but is harder to store and distribute as it needs to be kept extremely cold to retain its integrity.