Sanofi, GlaxoSmithKline hit with a major delay on Covid-19 vaccine program as their first jab flops in older adults
Hours after Pfizer and BioNTech won the backing of an FDA panel for their mRNA vaccine, Sanofi and GSK announced that their closely watched program to develop an adjuvanted vaccine to combat Covid-19 had hit a major setback.
The companies announced early Friday that they were delaying their development program for an adjuvanted recombinant protein-based Covid-19 vaccine after it failed among adults older than 49 in the study.
The researchers noted a “low immune response in older adults likely due to an insufficient concentration of the antigen.”
The collaborators, who had been hoping to launch a pivotal Phase III this month, are now planning a Phase IIb study of a revised vaccine with an improved antigen formulation. They plan to get that 2-shot study started in February, comparing it to an established vaccine on the market. The move will force a delay on launching supplies of the vaccine from H1 until the 4th quarter of 2021, at best, after some officials in Operation Warp Speed expect to see the end of the pandemic in the US.
GSK and Sanofi had projected getting hundreds of millions of doses of this vaccine out to world markets, representing a large portion of the vaccine doses the world would need to fight the pandemic. The companies had signed a deal to work with the WHO on equitable distribution of their vaccine, offering hope of a vaccine among the world’s less affluent countries. Their vaccine demanded a slower approach to development, but utilized what many believed was a more reliable technology that could deliver vaccine in bulk around the world. Now, it appears likely that Pfizer/BioNTech and Moderna will get approvals in the near term, as AstraZeneca faces questions about the lower efficacy it had seen in its late-stage study.
Any setback like this threatens to lengthen the time it takes to vanquish the virus as the first approved vaccines are likely to be in short supply for some time. It also will accelerate the virtual revolution now underway in the vaccine industry, as traditional tech makes way for a faster and evidently more reliable mRNA approach.
Sanofi and GSK, two of the world’s leading vaccine makers, are staying in the race, even if they’ve fallen well behind the leaders.

“We have identified the path forward and remain confident and committed to bringing a safe and efficacious COVID-19 vaccine. Following these results and the latest encouraging new preclinical data, we will now work to further optimize our candidate to achieve this goal,” said Thomas Triomphe, executive vice president and head of Sanofi Pasteur. “No single pharma company can make it alone; the world needs more than one vaccine to fight the pandemic.”
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