Sanofi, Glaxo covid vaccine works well in mid-stage study, shot on track

Sanofi and GlaxoSmithKline Plc reported positive results from a redo of a mid-stage study for their Covid-19 vaccine, putting the delayed shot on track for possible clearance by the end of the year.

Volunteers showed a similar antibody response to people who have recovered from the coronavirus, the companies said in a statement Monday. Those with evidence of a prior infection had a particularly high immune response after a single dose, suggesting the shot could be a good booster candidate.

The results come as a relief for the two partners, two of the biggest and most experienced companies in the vaccine field whose effort stumbled late last year when a dosing error delayed the initial study.

The new test enlisted 722 adults, from teens to 95-year-olds, in the U.S. and Honduras. Three different vaccine doses were injected three weeks apart and evaluated. Adults under 60 fared better overall, and there were no safety concerns, the companies said.

Now Sanofi and Glaxo plan to move on to a final-stage trial involving more than 35,000 participants from a range of countries. The study will begin in the coming weeks using the middle of the three dosage strengths. It will assess the shot against a number of variants, including the one first discovered in South Africa, the companies said.

The shot, which relies on technology used to make flu vaccines, could win regulatory approval in the fourth quarter, roughly a year after the one developed by Pfizer Inc. and BioNTech SE. Since then, a handful of other injections have received clearance. But as the world faces a growing number of variants and many countries struggle to get enough doses to immunize their population, the product could still play an important role in the pandemic -- especially since it doesn’t require freezing-cold temperatures.

“Multiple vaccines will be needed, especially as variants continue to emerge,” Thomas Triomphe, head of Sanofi’s vaccines unit, said in a conference call.

Sanofi and Glaxo also said they plan to conduct studies to see whether a lower dose can boost protection in volunteers regardless of which initial vaccine they received.

After the trial was delayed last year, the companies opted to help other drugmakers manufacture their own vaccines. Glaxo has agreed to produce as many as 100 million doses of CureVac NV’s messenger RNA shot, while Sanofi is supporting the production for Moderna Inc., Pfizer Inc. and Johnson & Johnson. Sanofi is also working on a second shot using mRNA, with early trial results expected in the third quarter.