De eerste analyse/evaluatie van de phase 3 trials gebeurt wanneer voldoende vrijwilligers covid-19 opgelopen hebben: dan pas wordt gekeken hoeveel van hen het vaccin of de placebo ontvingen. Tot nu toe heeft blijkbaar nog geen enkel bedrijf dat punt bereikt.
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'It's possible': the race to approve a Covid vaccine by Christmas
At least three companies close to revealing results of phase three trials, but to be approved for use safety has to be ensured
The race for a Covid vaccine is reaching a crucial stage, with the glimmer of a possibility that one of the leading contenders will be approved by Christmas.
In an interview with the Guardian, Kate Bingham, who heads the UK’s vaccine taskforce, said the UK was in “a very good place”.
But there are still hurdles to clear in the coming weeks.
The Guardian’s health editor, Sarah Boseley, explains the challenges ahead.
The frontrunners
Within weeks, the first results to show whether one of the vaccines actually works will emerge. With a vaccine hailed as the world’s best hope of halting the deaths and the social and economic destruction wreaked by the Covid pandemic, the world is holding its breath.
It could be Oxford University, partnered with drug company AstraZeneca. It could be Moderna in the US. Or it could be Pfizer and the German company BioNTech.
All three have either recruited the last of the tens of thousands of volunteers they need for the critical final trials or will shortly do so.
And sometime in November or December, their independent monitoring boards will “unblind” their secret data to find out whether fewer people given the experimental vaccines are getting Covid-19.
The excitement is palpable. Bingham understands that.
“I can just see that it’s such an incredibly sensitive topic, that everyone is so desperate to be out of lockdown and get back to normal that everyone grabs at straws,” she said.
“I think my key message is we’re in a very good place. The UK is well set up, we’ve got a very attractive portfolio. We are absolutely well-planned and well-organised in terms of having the right vaccines and knowing when they’re arriving.”
The UK has bought six of the hundreds of vaccines under development. It has two of the three companies heading down the final furlong – AstraZeneca’s and Pfizer’s. Bingham says she thinks there is a chance of a vaccine before Christmas.
“They have to have enough cases to show vaccine efficacy and the regulator has to approve it. If all of that happens, then it’s possible that we could have a vaccine this side of Christmas,” she said.
“But, you know, I’ve called it a slim chance and I think it is a slim chance. I think we’ve got a better chance of generating that data early next year, but it’s not to say it’s impossible.”
It all turns on the …
Phase three trials
In these final trials, recruiting up to 50,000 people, half get the experimental vaccine and half get something else. The trial is blinded. Nobody knows who has had what.
The codes for the vaccine allocation are held on secret computer files until enough people taking part in the trials have become infected with the coronavirus.
Then independent experts will look to see which drug they had.
The hope will be that most, if not all, of the people with Covid-19 will not have had the coronavirus vaccine.
Although volunteers are told how to reduce their own risk and may live in areas with low infection rates, this interim analysis could come quite quickly.
This is because the three companies have said they will start looking at the data when the infection sample sizes are still quite small.
Moderna has stated it will take a first look when it has 53 cases of coronavirus infection among participants in the trial, and again at 106. AstraZeneca has said it will look when there are 75.
Pfizer is waiting for only 32 and will look again at 62, 92 and 120 infections. They have largely been expected to declare first. Originally they planned to look in September.
CEO Albert Bourla was ambitious to have a vaccine by October – exciting Donald Trump among others, who thought it could be ready before the US presidential election.
But the timescale has slipped. On Tuesday, Pfizer said it hasn’t looked yet – which probably means there have not been enough infections.
And there is now a further delay because the US regulator, the Food and Drug Administration, has upped the safety stakes in the wake of the pausing of the Oxford University/AstraZeneca trial in which two people separately fell ill. The FDA has said it will not consider giving emergency approval to any vaccine unless there is safety data in at least half the participants for two months after the last dose is given. That means Pfizer could not submit before the end of November.
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https://www.theguardian.c(...)vaccine-by-christmasquote:
It may be time to reset expectations on when we’ll get a Covid-19 vaccine
The ambitious drive to produce Covid-19 vaccine at warp speed seems to be running up against reality. We all probably need to reset our expectations about how quickly we’re going to be able to be vaccinated.
Pauses in clinical trials to investigate potential safety issues, a slower-than-expected rate of infections among participants in at least one of the trials, and signals that an expert panel advising the Food and Drug Administration may not be comfortable recommending use of vaccines on very limited safety and efficacy data appear to be adding up to a slippage in the estimates of when vaccine will be ready to be deployed.
Asked Wednesday about when he expects the FDA will greenlight use of the first vaccines, Anthony Fauci moved the administration’s stated goalpost.
“Could be January, could be later. We don’t know,” Fauci, director of the National Institute of Allergy and Infectious Diseases, said in an online interview with JAMA editor Howard Bauchner.
On Tuesday, front-runner Pfizer revealed in an earnings call that the first interim analysis in its Phase 3 clinical trial has not yet occurred. That means there hadn’t yet been enough Covid infections among the trial participants to take a first stab at analyzing whether the people randomly assigned to receive vaccine were infected at a lower rate than people who were assigned to get a placebo injection.
It’s possible that the company will cross that threshold sooner rather than later. But Pfizer, which has been one of the most aggressive players in the vaccine race, had earlier predicted it would know by the end of September if its vaccine worked — an estimate that was later pushed back to late October. The company now projects that it could apply to the FDA for an emergency use authorization for the vaccine, which it is developing with BioNTech, in mid-November.
It is important to note that, to date, none of the vaccines being developed for the U.S. market has been proven to be effective in preventing Covid-19 disease. Early stage clinical trials have shown what appear to be promising signals; multiple vaccines have triggered production of important antibodies in people who have been immunized.
But data generated in a few hundred people aren’t enough to determine whether a vaccine will actually fend off illness. That answer comes from large, Phase 3 trials, five of which are now underway in the United States. Their findings will ultimately tell us how soon vaccines may start to be rolled out to the masses.
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https://www.statnews.com/(...)-a-covid-19-vaccine/