Drugmakers made big promises for a quick turnaround on coronavirus vaccines. The moment of truth for the front-runners is coming as soon as this month.
The first results showing whether a vaccine can stop people from getting the virus could come by mid-September from AstraZeneca Plc, according to Airfinity Ltd., an analytics company that tracks drug trials.
The drugmaker has pledged as many as 30 million doses to the UK by the end of the month.
The WHO counts 176 COVID-19 vaccines in development, of which 33 have entered human trials.
Two other contenders — the US's Moderna Inc. and the US-German partnership of Pfizer Inc. and BioNTech SE — may also have initial data before a key Food and Drug Administration (FDA) meeting on virus vaccines scheduled for October 22, Airfinity said.
The federal government has told states to prepare for a vaccine by November 1. A fourth candidate, China's Sinovac Biotech Ltd., could have preliminary results shortly after the FDA meeting.
These early results will be far from the full picture.
They're what's known as interim readouts — snapshots taken before a study is complete, with only a fraction of the data. The World Health Organization on Monday cautioned against approving a vaccine before its full risks and benefits are clear.
But with the virus resurgent in Europe and continuing to spread in India and the Americas, the initial numbers will be an important early indicator.
The first results should be enough to "give us a very good idea of where we're heading," Airfinity Chief Executive Officer Rasmus Bech Hansen said.
"They are moving faster than one could have anticipated."
Airfinity's projections are based on publicly available data on trial enrollment and design, together with infection rates in places where patients are enrolled.
Each of these experimental vaccines has already shown promise in smaller trials designed to flag any serious safety concerns and show whether candidates can spur some response from the immune system. Early safety data is key; unlike drugs, vaccines are typically given to relatively healthy people and shouldn't create severe risks.
Tens of thousands of participants
The real proving ground, though, is a study big enough to show with a high degree of certainty whether a vaccine candidate can work in the real world. This requires tens of thousands of participants, compared to the few hundred people who took the vaccines in early-stage trials.
Drugmakers would usually wait for final results before requesting regulatory approval, and the trio of front-runners are on track to get that full data by the end of the year, Airfinity says.
In the US, that might not be fast enough.
Overwhelmingly positive interim results could lead to studies being stopped early and the vaccines being rushed to the public, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told the Los Angeles Times earlier this week.
Promising initial data
Political pressure will be high to approve a vaccine if even the initial snapshot of data from these trials is promising. President Donald Trump has said a vaccine is possible by the November 3 election and accused the FDA of trying to slow the approval process.
Commissioner Stephen Hahn said last week he's open to clearing a vaccine under an emergency use authorization, which is based on more limited data.
The Centers for Disease Control and Prevention (CDC) asked states in a letter to prepare for vaccine distribution sites to be "fully operational" by November 1.
The agency declined to comment on the letter.
Interm data by October 15
Russia and China, meanwhile, have already cleared experimental vaccines for limited use before testing was complete.
Pfizer has said it's on track to have enough data for an authorization as early as October. Based on how quickly and where it's currently recruiting people for its 30,000-person trial, it will probably be the first US drugmaker with interim data — by October 15 — but won't have full results until November 17, Airfinity projects.
A Pfizer spokeswoman declined to comment on how many virus cases it will need to see in order to get results in the trial.
Companies testing vaccines in the U.S., where the virus has spread more quickly than in Europe for the past several months, may have an advantage in potential volunteers and infections.
AstraZeneca said it expects results later this year, depending on the rate of infection in the communities where it's running trials.
J&J said it still plans to start its late-stage test this month, with first batches of vaccine available for potential emergency use in early 2021, pending the study results. Sinovac declined to comment. Moderna declined to comment on the time-frame for its data readouts.
The drugmakers have already made deals to supply hundreds of millions of doses to governments around the world.
The WHO has said any vaccine should be shown to be effective in at least half the people who get it to gain clearance.
It will be important to follow participants in the trials long enough to see whether serious side effects emerge, WHO Chief Scientist Soumya Swaminathan said on Monday.
A premature approval would make it hard to continue studying the vaccine in randomised trials, she said.
The agency counts 176 COVID-19 vaccines in development, of which 33 have entered human trials.
"What's going to be really important, I think, is to make decisions based on science," Swaminathan said, warning that an "inadequately studied" vaccine could present either safety problems or "low efficacy, thereby not doing the job of bringing an end to this pandemic."