British pharmaceutical firm AstraZeneca has unveiled positive interim results from the Phase 1/2 COV001 trial of its potential Covid-19 vaccine AZD1222, licensed from the Oxford University.

In the clinical trial, AZD1222 was tolerated with no early safety concerns and shown strong immune responses against the SARS-CoV-2 virus in all the participants evaluated.

Previously called ChAdOx1 nCoV-19, AZD1222 was jointly developed by the University of Oxford and its spin-out company Vaccitech, and was licensed by AstraZeneca in May 2020.

COV001 is a single-blinded, multi-centre, randomised controlled Phase 1/2 clinical trial that enrolled 1,077 healthy adult participants, aged between 18 and 55 years, to evaluate the single dose of AZD1222 versus meningococcal conjugate vaccine, MenACWY.

‎AstraZeneca biopharmaceuticals R&D executive vice president Mene Pangalos said: “We are encouraged by the Phase I/II interim data showing AZD1222 was capable of generating a rapid antibody and T-cell response against SARS-CoV-2.

“While there is more work to be done, today’s data increases our confidence that the vaccine will work and allows us to continue our plans to manufacture the vaccine at scale for broad and equitable access around the world.”

AZD1222 induced neutralising activity against SARS-CoV-2 in 91% participants in COV001 trial

The company said that a single dose of its potential Covid-19 vaccine administered for one month in COV001 trial, induced increased antibodies to the SARS-CoV-2 virus spike protein by four times in 95% of participants.

In addition, AZD1222 vaccine has induced a T-cell response, with peak response on day 14, and was maintained two months after injection.

Astra Zeneca said that neutralising activity against SARS-CoV-2 was observed in 91% of the study participants after one month of vaccination and the same response was observed in all the participants with a second dose.

The amounts of neutralising antibodies observed in participants who were administered either one or two doses of the vaccine were identical with those seen in convalescent Covid-19 patients, and strong correlations were observed across neutralisation assays, said the company.

Furthermore, the late-stage Phase 2/3 trials are currently being conducted in the UK, Brazil and South Africa and are planned to begin in the US. The clinical trials are aimed at determining the capability of AZD1222 vaccine to protect subjects from Covid-19 and evaluate its safety and immune responses.

Oxford Vaccine trial chief investigator Andrew Pollard said: “The interim Phase 1/2 data for our coronavirus vaccine shows that the vaccine did not lead to any unexpected reactions and had a similar safety profile to previous vaccines of this type.

“The immune responses observed following vaccination are in line with what we expect will be associated with protection against the SARS-CoV-2 virus, although we must continue with our rigorous clinical trial programme to confirm this.

“We saw the strongest immune response in participants who received two doses of the vaccine, indicating that this might be a good strategy for vaccination.”