(Reuters) – Pfizer Inc. is betting that its coronovirus vaccine candidate will show early evidence of effectiveness in its clinical trial, according to company and internal documents reviewed by Reuters, describing how the trial is being run .
In recent weeks, Pfizer has said that it should know by the end of October whether the vaccine, developed in conjunction with Bioentech SE of Germany, is safe and effective. If the vaccine has been shown to work by then, Pfizer has said it will quickly seek regulatory approval. It has not stated what data it will use.
President Donald Trump, who is seeking re-election, has said that a vaccine to fight the coronovirus epidemic is possible before the November 3 US vote, raising concern over political interference. Scientists have questioned whether drug makers will have enough evidence to achieve success by that time.
Pfizer’s clinical trial protocol tells the company, scientists, and regulators how the drug manufacturer can show that its vaccine meets the efficacy and safety standards set by the US Food and Drug Administration.
A company’s protocol is presented to the FDA for review and is overseen by an independent panel of experts known as the Data and Safety Monitoring Board.
The protocol is called for the first assessment of the vaccine’s performance by the monitoring board after 32 trial participants were infected with a novel coronavirus. The trial, which began in July, has so far enrolled more than 29,000 people, with some receiving vaccines and others receiving placebo.
The FDA has stated that a coronovirus vaccine should prove to be at least 50 percent more effective than a placebo in a large-scale trial considered for approval. However, a small sample of infections in a clinical trial changes the calculation of how researchers meet that standard.
According to its protocol, Pfizer’s vaccine must be at least 76.9% effective to work on the basis of 32 infections. This would mean that more than six of those coronovirus cases would not have occurred among people receiving the vaccine, documents showed.
If the drugmaker’s vaccine did not meet the 76.9% efficacy target in this first interim analysis, it would face a difficult statistical significance threshold during subsequent interim evaluation, the biochemist reviewed the protocol.
Pfizer said its interim analyzes were designed to show conclusive evidence “if our vaccine meets stringent standards set by the FDA as soon as possible amid devastating epidemics.” Pfizer would not say whether it would use an interim analysis as a basis for seeking approval.
The FDA declined to comment on whether it would consider such data sufficient for approval.
Interim analysis is typically used by data and safety monitoring boards to determine if an experimental drug appears safe and effective to continue testing, or whether it should be stopped if a safety issue arises. .
But if a vaccine meets the FDA’s benchmark in interim analysis without any serious safety problems, it may help to use it as the basis for a treaty that would help the world to curb an epidemic. Has killed 940,000 people at the level, said Thomas Lumley, chair of biostatistics, University of Auckland in New Zealand
Another front-runner in the vaccine race, Modern Inc., told Reuters it would seek emergency FDA authorization to use its vaccine in high-risk groups if an interim evaluation of its testing showed at least 70 vaccines. The percentage was effective.
Modern, which made its protocol public on Thursday, said the first interim analysis of 53 infections is likely to come in November.
Some vaccine experts have said that drug manufacturers should wait to reach their final analysis of more than 150 cases before taking FDA approval. They note the speed at which vaccines are being developed for COVID-19, which can be a decade-long process.
Relying on more limited interim analyzes may reduce the effectiveness of the vaccine, as not enough trial participants fall ill, he said. Moving more quickly through the testing process also means that a pharmaceutical manufacturer may miss potential side effects that it can test if given longer.
“These interim analyzes indicate short cuts,” said Eric Topol, director of the Scripps Research Translational Institute in La Jolla, California. “You miss security issues and you may very well increase the benefits.”
In addition to Pfizer and Modern, Reuters reviewed clinical trial protocols for vaccine candidates developed by AstraZeneca PLC and Johnson & Johnson.
AstraZeneca conducted its first interim analysis when approximately 40 coronovirus infections were reported in participants. Its US trial is underway after a patient falls ill.
The first analysis of J&J will begin on 20 infections, starting on September 21, according to their protocol of mass testing.
AstraZeneca and J&J declined to comment.
Reporting by Marissa Taylor in Washington and Dan Levine in San Francisco; Editing by Michelle Gershberg and Will Dunham