New Trial Testing Reformulated Covid-19 Vaccine

Canal tugboat and Panama City skyline (A. Kotok)

22 Feb. 2021. Two drug makers are beginning a clinical trial to test their reformulated vaccine against Covid-19 disease, particularly among older populations. Sanofi Pasteur, the vaccines division of Sanofi in Paris, and GlaxoSmithKline in London say the trial will test its new vaccine among individuals in the U.S. and Central America.

The new Sanofi/GSK vaccine formula aims to improve on its previous version that in an earlier trial showed a low immune response among older adults, a population at higher risk of severe disease from Covid-19 infections. Science & Enterprise reported on the beginning of that early- and mid-stage, phase 1 and 2, trial in September 2020. By December, results from the trial showed immune responses in people age 18 to 49 comparable to those who recovered from Covid-19 infections, but a low response among older participants. The companies attributed the lower response to insufficient concentrations of antigen in the vaccine.

The joint vaccine uses uses an engineered protein from Sanofi Pasteur, extending a technology employed for its influenza vaccine. GSK is providing an adjuvant for the vaccine, which the company says can reduce the amount of vaccine needed per dose, allowing for faster large-scale manufacturing and distribution. In December, the companies said tests with lab animals show an updated version of the vaccine with reformulated antigens clears the virus from nasal passages and lungs, as well as protects against lung disease.

U.S., Honduras, Panama volunteers

“Over the past few weeks,” says Thomas Triomphe, head of Sanofi Pasteur in a statement, “our teams have worked to refine the antigen formulation of our recombinant-protein vaccine, based on learnings from our initial phase 1/2 study. We are confident that our vaccine candidate has strong potential and we are very encouraged by the latest preclinical data.”

The new trial is enrolling 720 volunteers in the U.S., Honduras, and Panama, with equal numbers of participants age 18 to 59, and age 60 and over. The mid-stage study is randomly assigning participants to receive one of three dosage levels of the Sanofi/GSK vaccine or a placebo in two doses, 21 days apart. The findings are expected to determine an optimum dosage for a worldwide late-stage clinical trial in the second quarter of this year.

The U.S. government has a multi-billion dollar investment in the Sanofi/GSK vaccine. In July, the companies received $2.1 billion from the U.S. Biomedical Advanced Research and Development Authority, or BARDA, and Department of Defense for support of clinical trials and an initial 100 million doses of the vaccine. The agencies have an option under the deal to acquire an additional 500 million doses later on. In addition, Sanofi and GSK plan to provide 200 million doses of its vaccine to the Covax facility, an international effort to make vaccines equitably available worldwide.

Sanofi says it started work on vaccines to counter emerging variants of the SARS-CoV-2 virus responsible for Covid-19 infections, to prepare for the next round of Covid-19 vaccines with GSK. The company is also collaborating with the biotechnology company Translate Bio in Lexington, Massachusetts on a Covid-19 vaccine based on messenger RNA, the same approach used by the two vaccines already authorized by the Food and Drug Administration.

More from Science & Enterprise:

• Biotech, UK Govt to Design Covid-19 Variant Vaccines
• One-Dose Covid-19 Vaccine Shown to Prevent Hospitalization
• Covid-19 Vaccine Shown Safe, Effective in Russian Test
• Novavax, J&J Return Mixed Covid-19 Vaccine Results
• Covid-19 Vaccine Shown Active Against Variants

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