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A Novavax’s Covid-19 vaccine was found to be nearly 90% effective in preliminary results from a key UK clinical trial, the company said, but in a separate trial it was found to be much less effective against a new variant of the coronavirus which was identified for the first time in the South. Africa.
In its trial of 15,000 volunteers in the UK, Novavax said, the vaccine has prevented nine out of 10 cases, including against a new strain of the virus circulating there. But in a study of 4,400 volunteers in South Africa, the vaccine was found to be only 49% effective. In the 94% of the study population who did not have HIV, the efficacy was 60%.
In the UK trial, Novavax observed 62 cases of symptomatic Covid-19, including 56 in the placebo group and six among the volunteers who received the vaccine. A patient on placebo developed severe Covid-19, compared to zero in the vaccinated group. The company provided few details on the safety of the vaccine, saying only that serious side effects were rare and balanced between the vaccine and placebo groups of the studies.
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In the South African study, 29 cases of symptomatic Covid-19 were observed in the placebo group and 15 in the vaccine group.
It’s unclear whether this data will be sufficient for US approval, or whether the US will wait for further data, as appears to be doing with vaccines developed by AstraZeneca and the University of Oxford. Novavax has said it plans to file an emergency clearance application in the UK in the coming months, once it has final data from its clinical trial there. The company said it had been in contact with the Food and Drug Administration but did not provide details of its plans.
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Operation Warp Speed, the US government’s vaccine incubator, is conducting its own large US trial of the Novavax vaccine in the United States and Mexico. Researchers expect to complete registration during the first half of February.
Carlos del Rio, professor of infectious diseases at Emory University School of Medicine, said the overall efficacy figures were impressive and the vaccine was showing at least some efficacy against the variant first identified in South Africa.
Likewise, the lesser effectiveness against this variant could be a vulnerability in the United States, where it was first reported in South Carolina on Thursday, and elsewhere.
Nahid Bhadelia, medical director of the Special Pathogens Unit at Boston Medical Center, stressed that while the decline in effectiveness against the South African variant is bad news, the results are not “a complete washout.” The vaccine, she said, “can still make a huge difference.” But the results also underscore the important work of figuring out how to develop callbacks against new variants, especially given news that the South African strain, B1351, has been found in South Carolina.
Novavax said it was already working on a new version of the vaccine designed to fight more infectious strains of SARS-CoV-2, which could work as a booster for people already inoculated. But clinical tests are not expected until the second quarter of this year.
Some experts cautioned against over-interpreting the efficacy results in the South African trial, noting that they represented a relatively small number of cases in a preliminary analysis.
“I’m not sure it’s disappointing. UK data looks very good. The data from South Africa may be more nuanced, ”said Anna Durbin, professor at the Johns Hopkins Bloomberg School of Public Health, noting that each trial defined symptomatic disease slightly differently. She said she would be interested in seeing more data on the severity of the disease in the reported cases.
Scott Gottlieb, former FDA commissioner and Pfizer board member, said he didn’t think it was a surprise that the vaccine was less effective against the new strain.
“We have already seen experimentally that there is a decrease in neutralization against this variant with other vaccines, and we should expect this to be common to all vaccines that use the original spike protein as an epitope. , regardless of how this protein is. be delivered, ”he said.
More data will be available with the Johnson & Johnson results, expected soon, as this trial will include patients from Brazil and South Africa.
“I think this raises the issues of developing boosters based on these new variants, and building a regulatory process that allows this type of incremental innovation and tracking to reach the market based on these new variants. something that is not completely new and complete. blown results studies, ”Gottlieb said.
The data from Novavax comes as countries around the world scramble to obtain enough doses of the vaccine to protect their populations. In the United States, the federal government has struggled to meet demand for doses of the only two licensed vaccines, from Moderna and its partners Pfizer and BioNTech.
Novavax said it plans to produce around 2 billion doses of its vaccine in 2021. The United States has signed a contract to purchase 100 million and has the option of acquiring more.
Like all Covid-19 vaccines that are used or are in final testing, the two-dose injection of Novavax works by mimicking a protein called spike, which is found on the surface of SARS-CoV-2. When the immune system sees this protein, it produces antibodies against it, thus protecting the body from a case of Covid-19.
But Novavax is using the most proven technology among racing pioneers to develop Covid-19. The first two vaccines authorized in the United States use a technology called mRNA, which slides genetic material into cells to create a protein that stimulates the immune system. Still others in development, like one from Johnson & Johnson and one from AstraZeneca, are using genetically engineered viruses to do something similar.
Like some approved vaccines, Novavax’s vaccine makes fragments of the spike protein in insect cells and then adds another chemical, called an adjuvant, to stimulate the immune system to respond. This approach is used in an approved influenza vaccine sold by Sanofi, and it was the approach that Sanofi and GlaxoSmithKline planned to use in their own Covid-19 vaccine.
The similarities are not entirely coincidental. Gale Smith, the former scientific director of the company that developed this vaccine, is now a scientist at Novavax. But as the drug giants stumbled, Novavax, a small company that had yet to bring a product to the market, mostly hit their mark.
The company presented promising preliminary data in August showed levels of neutralizing antibodies that were roughly quadruple those seen in patients who had recovered from Covid-19, among the best for all vaccines in initial tests. These same results were published in the New England Journal of Medicine in September.
In July, Novavax received funding of $ 1.6 billion of Operation Warp Speed to intensify its manufacturing processes, with the agreement that the resulting 100 million doses of vaccine would be the property of the US government.
The good news, said Natalie Dean, a biostatistician at the University of Florida, is that, since the beginning, several different vaccine technologies have been developed against Covid-19. It makes the world more ready for what is to come.
“That’s why it’s important to have an open pipeline,” Dean said. “At every step of the way, we don’t want to put all of our eggs in one basket. And it’s the same situation. We still don’t know the durability, we don’t know how vaccines work against different variants. At all stages, we want a variety of approaches. “
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