Sanofi/GSK Booster Shot Looking Good But Delayed Until 2022

Michel Stoupak/NurPhoto via Getty Images

Michel Stoupak/NurPhoto via Getty Images

Sanofi and GlaxoSmithKline reported that their potential COVID-19 booster shot delivered good immune response in its preliminary clinical trials.

Michel Stoupak/NurPhoto via Getty Images

On Wednesday, the French and British drugmakers Sanofi and GlaxoSmithKline reported that their potential COVID-19 booster shot delivered good immune response in its preliminary clinical trials. The initial data provide optimism, but the companies announced a delay in the COVID-19 vaccine booster candidate data until 2022.

Early data from a clinical trial shows Sanofi and GSK’s single-dose COVID-19 vaccine booster candidate produces a strong immune response and has a good safety and tolerability profile, a positive note on their vaccine’s improving shot effectiveness. Their COVID-19 vaccine candidate uses Sanofi’s seasonal influenza vaccines combined with an adjuvant, a substance that acts as a booster to the shot developed by GSK.

The two drugmakers kicked off the Phase III trial for the COVID-19 shot in May, and they announced the vaccine could be authorized at the end of the year. The early data was promising but the companies reported they needed more time to get sufficient trial results. “Vaccine sales would be almost entirely upside to current (consensus), so no change to estimates likely, but success could be a welcome boost to the narrative,” noted the companies.

“The booster was well tolerated, with a safety profile similar to currently approved COVID-19 vaccines. This is the most comprehensive booster trial to date to explore boosting across different vaccine technologies used for primary vaccination.” the companies said in a statement.

The test has been administered for all age groups and those who have received approved primary vaccines, AstraZeneca, Johnson & Johnson, Moderna, and Pfizer-BioNTech. The booster shot was tested four and ten months after a full immunization coverage; the trial period was initiated when the Omicron variant was not spreading.

“Preliminary results from the VAT0002 clinical trial investigating the safety and immunogenicity of the booster showed neutralizing antibodies increased nine to 43-fold regardless of the primary vaccine received (AstraZeneca, Johnson & Johnson, Moderna, Pfizer/BioNTech) and for all age groups tested” Sanofi stated.

Ongoing Late-Stage Phase III Trial Update

Sanofi and GSK expressed delay in their potential COVID-19 vaccine. They said it won’t be ready until next year as they need more time with its ongoing late-stage Phase III study. It is expected to continue in 2022 with results in the first quarter.

“These preliminary data show we have a strong booster candidate, whatever primary vaccine you have received,” said Thomas Triomphe, head of Sanofi Pasteur, the company’s vaccines division. He added that it was a challenge pursuing late-stage clinical trials in a “quickly shifting environment.” Still, the booster findings are relevant to “evolving public health needs,” especially as the world gears up for the more contagious Omicron variant.

Regulatory authorities require efficacy to be demonstrated on more people who the virus has not infected before they can file booster data. “To provide the necessary data to regulatory authorities for the booster vaccine submission, the trial will continue to accrue the number of events needed for analysis, with results expected in Q1, 2022,” the companies said in a statement.

The vaccine’s development delay put the companies behind their competitors in the race for COVID-19 shots.

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