Moderna releases details on its vaccine trial; analysis of data might start at end of the year
Biotech company Moderna released a 135-page document Thursday that spells out the details of how it is conducting the late-stage trial of its coronavirus vaccine and how safety and efficiency will be determined.
The document suggests that the first analysis of the trial data may not be conducted until late December and that there may not be enough information then to determine whether the vaccine works. Subsequent analyses, scheduled for March and May, are more likely to provide an answer.
Those timelines mesh with the cautionary estimates from many researchers and stand in contrast to President Donald Trump’s predictions that a vaccine will become widely available before the end of this year.
Scientists have been calling on vaccine-makers to share their study plans, known as protocols, so outside experts can evaluate them. Until now, none of the nine companies that are testing vaccines in late-stage clinical trials had done so.
Moderna, AstraZeneca and Pfizer, which is collaborating with German company BioNTech, are among the front-runners in the global race to produce a vaccine to fight the pandemic.
AstraZeneca’s trial stopped temporarily because of serious illness in a participant. It has resumed in Britain, but not in the U.S.
Pfizer said Saturday that it planned to expand its trial to 44,000 participants from 30,000 but that it still expected to have efficiency results by the end of next month.
Dr. Tal Zaks, Moderna’s chief medical officer, said his company was the first of the coronavirus vaccine-makers to release its protocol and that pharmaceutical companies usually are reluctant to do so, for competitive reasons.
“I’m proud of doing that,” he said. “I don’t think there’s much there that we’re disclosing that hasn’t already been spoken to, but let the public be the judge of that.”
The action might encourage other vaccine-makers to do the same, said Dr. Stéphane Bancel, Moderna’s CEO.
Dr. Eric Topol, a clinical trial expert at Scripps Research in San Diego, gave the company “big kudos” for sharing the information but said he was disappointed by some of the details. For example, the company intends to include in its data people who developed relatively mild cases of COVID-19. Topol said more compelling evidence of the vaccine’s effectiveness would be produced if the company counted only moderate to severe cases.
In addition, the protocol allows for the possibility of stopping the trial early after a relatively small number of cases. Stopping early could lead to an exaggerated perception of the vaccine’s efficiency and could miss safety problems that might turn out to be significant later if the vaccine is given to millions of people.
“Take the time, the extra weeks,” Topol said. “No shortcuts. … I’d like to see it done right and not stopped early.”
The company’s coronavirus vaccine, developed in collaboration with scientists from the National Institutes of Health, was the first to be tested in humans. The Phase 3 study now underway has enrolled more than 25,000 of its intended 30,000 volunteers, and Zaks said the enrollment should be complete in the next few weeks.
About 28 percent of the participants are Black, Latino or from other populations that have been particularly hard hit by the disease. A diverse enrollment has been considered essential to make sure that the findings apply to people from as many backgrounds as possible.
To determine the vaccine’s efficiency, COVID-19 cases are counted only if they occur two weeks after the second shot. Some patients are already two weeks beyond the second shot, but Zaks said he did not know if any trial participants had contracted the disease yet.
A total of 151 cases — spread between the vaccine and placebo groups — would be enough to determine whether the vaccine is 60 percent effective. The Food and Drug Administration has set the bar at 50 percent.
But if the vaccine turns out to be highly effective, with a statistically significant difference emerging between the two groups with fewer than 151 cases, efficiency could be proved sooner, Zaks said.
The numbers will be watched by a panel of independent experts picked by the National Institutes of Health. The same group also will monitor several other trials.