Moderna’s announcement of positive data on a Phase 1 trial of its Covid-19 vaccine in May was met with skepticism from some experts, who noted that the company had not included much detail on the trial’s outcome in their press release. Now, two months later, that detail is here.
The vaccine “induced anti–SARS-CoV-2 immune responses in all participants, and no trial-limiting safety concerns were identified,” says a New England Journal of Medicine paper published on Tuesday evening. “These findings support further development of this vaccine.”
Moderna stock (ticker:MRNA) spiked in after-hours trading following the 5 p.m. announcement, with the stock up 13% and rising at 5:10 p.m.
Scientists and investors are likely to pore over the paper in the coming hours. But initially, two items seem important to note: At the 100- microgram dose level, which Moderna will test in its Phase 3 trial starting this month, the vaccine elicited levels of neutralizing antibodies after two doses that were four times higher than investigators found in three patients who had recovered from Covid-19 infections.
That’s good news. Also disclosed in the paper is that all 15 patients at the 100-microgram dose level reported so-called “systemic adverse events” after the second injection of the vaccine. Eighty percent reported fatigue and chills, while 60% reported headaches. Six reported a fever.
All of the reported symptoms went away, and were mild or moderate in severity.
The paper also found that the vaccine elicited T-cell responses in trial participants, another form of immune response that some scientists believe may be key to preventing Covid-19 infections.
The authors of the paper noted that they have so far not been able to track how long the immune responses induced by the vaccine last.
“These safety and immunogenicity findings support advancement of the mRNA-1273 vaccine to later-stage clinical trials,” the authors wrote.
A separate signed editorial in the New England Journal by Dr. Penny Heaton, CEO of the Bill & Melinda Gates Medical Research Institute, says: ”The safety and immunogenicity data in this preliminary report are promising, and they support continued development of this vaccine. However, we must bear in mind the complexity of vaccine development and the work still to be done before Covid-19 vaccines are widely available.”
Moderna confirmed Tuesday that it plans to begin a 30,000 participant Phase 3 trial of its Covid-19 vaccine on July 27. The company is testing a two-dose regimen of a 100-microgram dose of its vaccine, called mRNA-1273, in the Phase 3 trial.
According to Moderna’s press release, the 14 patients in the Phase 1 trial who received 100-microgram doses of the vaccine had an average level of neutralizing antibodies that were 4.1 times higher than the level found in the blood of three patients who had recovered from Covid-19 infections.
The company’s CEO has said that he hopes to have data from the Phase 3 study by Thanksgiving. Shares of Moderna are up 283.6% so far this year. The stock rose 4.5% during the trading day on Tuesday.
Write to Josh Nathan-Kazis at firstname.lastname@example.org