Broader Vaccine Plan in West Dealt Setback by Sanofi-GSK Delay

By Matthew Dalton

PARIS -- Drugmakers Sanofi SA and GlaxoSmithKline PLC on Friday said their coronavirus vaccine won't be available in the middle of next year as expected after receiving mixed effectiveness data from a clinical trial, complicating plans in the U.S. and Europe to quickly vaccinate broad swaths of their populations.

The U.S. and Europe were counting on tens of millions of doses of the Sanofi-GSK vaccine to be available as early as spring, a key part of their vaccination strategies for the coming year. The vaccine constitutes 10% of total global coronavirus vaccine doses that were expected from Western pharmaceutical companies next year, according to U.S. investment bank Jefferies Group.

The companies said that interim results showed the compound produced a weak immune response in people older than 50, who are a key demographic because they are more vulnerable to Covid-19. Sanofi and GSK plan to reformulate the vaccine to fix the problem and start new clinical trials in February, with the goal of making it available in the fourth quarter of next year.

"This shows what we know, that it is not always easy to develop a new vaccine to the point of being used to prevent the disease," said Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine. "It is possible that adjustment of doses and constituents of the vaccine could improve responses in the elderly, but again that is not guaranteed."

Sanofi and GSK received $2.1 billion from Operation Warp Speed, the U.S. government's coronavirus vaccine program, to accelerate the development and commercialization of the vaccine -- the biggest grant handed out by the U.S. program. That deal called for the companies to supply the U.S. with 100 million doses and gave the government an option to order an additional 500 million. The European Union ordered 300 million doses, and the U.K. another 60 million.

France was planning to begin its vaccination campaign this winter with the compound produced by Pfizer Inc. and BioNTech SE, the first coronavirus vaccine to be approved by regulators in the West, targeting nursing home residents. In the second phase, the authorities plan to use vaccines made by Moderna Inc., AstraZeneca and others on other at-risk populations. France was planning to use the Sanofi-GSK vaccine as it starts inoculating the general public in the spring.

The vaccine relies on technology used by Sanofi to produce influenza vaccines combined with an "adjuvant" -- a substance that augments immune responses to a vaccine -- made by GSK, one of the world's leading vaccine manufacturers. The vaccine was expected to help ease the logistical challenges of mass vaccination since it can be stored at nonfreezing temperatures, unlike the Pfizer-BioNTech vaccine.

That vaccine must be transported and stored at around -70 Celsius, requiring massive investments in ultracold storage facilities. The next vaccine likely to be approved, by Moderna, doesn't need ultracold storage but must still be kept at subfreezing temperatures.

One downside of the kind of vaccine technology used by Sanofi-GSK is that it was known going into the trial to produce weaker immune responses in older patients, said Penny Ward, visiting professor in Pharmaceutical Medicine at King's College London.

To address the problem, Sanofi and GSK said that they would increase the vaccine's concentration of antigen, substances that spark the immune system to generate antibodies and other forms of immune protection against the coronavirus.

"The results of the study are not as we hoped," said Roger Connor, president of GSK's vaccines division. "Our aim now is to work closely with our partner Sanofi to develop this vaccine, with an improved antigen formulation."

Write to Matthew Dalton at Matthew.Dalton@wsj.com

(END) Dow Jones Newswires

December 11, 2020 09:40 ET (14:40 GMT)

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