Sanofi, GSK kick-start phase 3 COVID-19 vax test as the pair targets variants, Q4 approval

Just two weeks after seeing a positive data readout from a small midstage test, Sanofi and GlaxoSmithKline got the signoff for a much bigger phase 3, which could lead to a full approval by the fourth quarter.

After fumbling their first attempt, once rivals but now partners Sanofi and GSK in mid-May passed a small phase 2 COVID-19 vaccine test, where its adjuvanted recombinant shot “achieved strong rates of neutralizing antibody responses,” which the pair said was “in line” with those measured in people who have recovered from COVID-19.

The trial was small, in fewer than 800 subjects and primarily looking at immunogenicity. Now, the U.K. and French Big Pharmas are starting their much bigger phase 3 program of more than 35,000 adults from across the U.S., Asia, Africa and Latin America.

The primary endpoint of the study, which is being partly funded by the Biomedical Advanced Research and Development Authority, is for its vaccine to stop symptomatic COVID in adults who have not had a prior infection, with secondary endpoints being the prevention of severe disease and stopping asymptomatic infection.

In a two-stage approach, the study looks at the efficacy of a vaccine formulation targeting the original D.614 virus (the so-called original Wuhan virus), while a second formulation will target the B.1.351 (so-called South African) variant.

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Sanofi said recent data point to the fact that antibodies created against the B.1.351 variant “may provide broad cross-protection against other more transmissible variants” and could therefore boost its use against other variants circulating the globe.

It will also, likely from next month, start a trial looking at the vaccine as a booster shot, given regardless of what vaccine a subject had initially been given. This booster market will likely become its main revenue driver in the future, given how far behind it is from its rivals.

Should all go to plan, the pair believes the vaccine could be approved or authorized in the fourth quarter of 2021. Manufacturing will begin in the coming weeks “to enable rapid access” to the vaccine should it be approved.

“We are encouraged to see first vaccinations starting to take place in such an important, pivotal phase 3 study, as we believe that our unique technology platform will provide a clinically-relevant vaccine option,” said Thomas Triomphe, executive vice president and global head of Sanofi Pasteur.

“We have adapted our vaccine development strategy based on forward-looking considerations as the virus continues to evolve, as well as anticipating what may be needed in a post-pandemic setting. This trial is testament to the urgency and agility in our approach to help overcome the ongoing impact of this pandemic.”