Moderna on May 18 reported positive results from an early trial of its CCP virus vaccine.
The Massachusetts-based biotechnology company said that preliminary data from the trial showed that all 45 participants produced antibodies against the CCP virus.
Volunteers received doses of 25 micrograms, 100 micrograms, or 250 micrograms nearly a month apart. At day 43, the levels of antibodies in the group receiving the lowest dosage were at the levels seen in blood samples from people who have recovered from COVID-19.
The levels for the group receiving 100-microgram doses “significantly exceeded” the levels of people who have recovered from the disease.
Data on the second dose isn’t yet available for the group who received the highest dosage.
Antibodies are a blood protein produced by the immune system to combat viruses and other foreign material.
“We couldn’t be happier about this interim data,” Stéphane Bancel, Moderna’s CEO, said in a conference call on May 18.
The trial started in Seattle on March 16. It’s led by the National Institutes of Health’s National Institute of Allergy and Infectious Diseases. It was recently expanded to include older age groups.
The vaccine produced neutralizing antibodies in at least eight participants; data wasn’t yet available for the other volunteers. Neutralizing antibodies, or titers, are a small subset of antibodies that bind to a virus in a manner that blocks infection.
“These interim Phase 1 data, while early, demonstrate that vaccination with mRNA-1273 elicits an immune response of the magnitude caused by natural infection,” Tal Zaks, Moderna’s chief medical officer, said in a statement.
“When combined with the success in preventing viral replication in the lungs of a pre-clinical challenge model at a dose that elicited similar levels of neutralizing antibodies, these data substantiate our belief that mRNA-1273 has the potential to prevent COVID-19 disease and advance our ability to select a dose for pivotal trials.”
Moderna is perhaps the furthest along in developing a vaccine against the CCP virus, with plans to start a phase 3 trial in July. Federal officials recently cleared the vaccine for phase 2 trials.
Interim results showed the vaccine was generally safe and well tolerated, researchers said. One participant who received the 100 microgram doses experienced redness around the injection site. And three volunteers who received the highest dosing level experienced grade-three systemic symptoms.
“I believe these flu-like symptoms are really an indirect measure of a strong immune response,” Zaks said in the call. “That said, all adverse events have been transient and self-resolving.”
The biggest risk forward, he said, is not having enough cases to demonstrate the vaccine candidate works in phase 3. That worry has led some to propose conducting human challenge trials.
Dr. Scott Gottlieb, former commissioner of the Food and Drug Administration, said the early results are encouraging.
“Early data shows it generates robust immune reaction, and it’s dose dependent. Getting dose right is key,” he said in a statement.
Based on the interim results, the phase 2 study will be amended to focus on two dose levels: 50 micrograms and 100 micrograms. The phase 1 study, which is still ongoing, will also change to include a 50 microgram dose cohort across each of the three age groups.