UK COVID-19 Vaccine Begins Phase II/III Trials

Researchers at the University of Oxford are now recruiting volunteers for phase II/III trials of a COVID-19 vaccine in human volunteers, according to a University press release.

The phase I trial of the vaccine candidate ChAdOx1 nCoV-19 in 1000 healthy adult volunteers aged 18 to 55 years began in April and follow-up of the completed immunizations is in progress.

This next phase will enroll more than 10 000 adults and children and in the smaller phase II trial, expand the age range of participants to include groups of older adults (aged 56-69 and >70 years) and younger children (aged 5-12 years). Addition of these groups will allow researchers to assess the immune response across the lifespan, looking for variation in how well the immune system responds in older adults or children.

The randomized, controlled phase III trial will evaluate vaccine efficacy in adults aged <18 years.

Adult participants in both phase II and phase III will be randomized to receive 1 or 2 doses of either the ChAdOx1 nCoV-19 vaccine or a licensed vaccine (MenACWY) that will be used as a control.

ChAdOx1 nCoV-19 is made from a virus (ChAdOx1), a weakened version of adenovirus, which causes infections in chimpanzees, and contains the genetic material of the SARS-CoV2 spike protein. While the recombinant adenovirus vector (ChADOx1) was chosen to generate a strong immune response from a single dose, it is not replicating so cannot produce infection in human volunteers, according to a statement from vaccine development collaborator AstraZeneca.

"The clinical studies are progressing very well and we are now initiating studies to evaluate how well the vaccine induces immune responses in older adults, and to test whether it can provide protection in the wider population," said Professor Andrew Pollard, head of the Oxford Vaccine Group, in the Oxford University news release.

Public, private collaboration

"The COVID-19 vaccine trial team have been working hard on assessing the safety and immunogenicity of ChAdOx1 nCoV-19, and preparing to assess vaccine efficacy," added Sarah Gilbert, professor of vaccinology at the Jenner Institute, Oxford, in the same release. "We have had a lot of interest already from people over the age of 55 years who were not eligible to take part in the phase I study, and we will now be able to include older age groups to continue the vaccine assessment. We will also be including more study sites, in different parts of the country."

AstraZeneca on what day received a pledge of more than $1 billion from the U.S. Biomedical Advanced Research and Development Authority to support development and global production and distribution of the University of Oxford's ChAdOx1 nCoV-19 vaccine. The company and University of Oxford had previously announced an agreement on the collaboration.

'We are so proud to be collaborating with the University of Oxford to accelerate the development and globalization of this potential new vaccine against COVID-19 infection. The speed at which this new vaccine has advanced into late-stage clinical trials is testament to Oxford’s ground-breaking scientific research," said Mene Pangalos, executive vice president, BioPharmaceuticals R&D, AstraZeneca, in the Oxford University statement.

"We will do everything in our power to engage with governments, multilateral organizations and partners around the world to increase production and distribution and ensure rapid, fair and equitable distribution of a globally accessible vaccine."

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