Sanofi and GlaxoSmithKline (GSK) have initiated a Phase I/II clinical trial to evaluate their adjuvanted recombinant protein-based vaccine candidate against Covid-19.

The vaccine combines Sanofi’s recombinant protein-based technology with GSK’s established pandemic adjuvant technology.

Preclinical results demonstrated an acceptable reactogenicity profile, while data on two injections of the vaccine revealed levels of neutralising antibodies comparable to those found in humans who recovered from the disease.

During the randomised, double blind and placebo-controlled Phase I/II trial, the vaccine candidate’s safety, reactogenicity and immunogenicity will be assessed in 440 healthy adults at 11 sites in the US.

Initial data from the trial are expected in December this year and will support the launch of a Phase III trial in the same month.

If the data is enough to support a licensure application, the companies intend to seek regulatory approval in the first half of next year.

Sanofi Pasteur executive vice-president and global head Thomas Triomphe said: “The initiation of our clinical study is an important step and brings us closer to a potential vaccine which could help defeat Covid-19.

“Our dedicated teams and partner continue to work around the clock as we aim to deliver the first results in early December. Positive data will enable a prompt start of the pivotal Phase III trial by the end of this year.”

Sanofi is responsible for the clinical development and registration of the vaccine.

The companies are also working to scale up manufacturing of the antigen and adjuvant with an aim to produce up to one billion doses next year.

Development of the vaccine candidate is being supported using funding and an alliance with the US Biomedical Advanced Research and Development Authority.

In July this year, the US Government has committed to providing up to $2.1bn to Sanofi and GSK for development, manufacturing, scale-up and delivery of an initial 100 million doses of the companies’ Covid-19 vaccine candidate.

This trial comes after Sanofi reported that the Phase III trial of Kevzara failed to meet the primary and key secondary endpoints in Covid-19 patients.