Moderna's stock surged 12% on Wednesday after the biotech company released promising data on its potential coronavirus vaccine trial, saying it generated a "robust" immune response.
The vaccine candidate produced neutralizing antibodies, which scientists believe is important for building immunity against the virus, in all 45 patients tested in the trial, Moderna scientists reported Tuesday night in the New England Journal of Medicine. Additionally, the antibodies that were produced were higher than those seen in people who have recovered from Covid-19.
The newly released data "puts us on a positive path towards a larger phase three trial with which we hope to demonstrate the safety and efficacy," Moderna chief medical officer Tal Zaks said Wednesday on CNBC's "Squawk Box."
Scientists caution that the phase one study was small, with just 45 individuals who were all healthy, and the results may differ for other populations, like those with underlying health conditions.
"I believe we have an ethical obligation to advance this vaccine as fast as possible given the unmet need on one hand and given what science enables us to do on the other," Zaks said. "I think it is incumbent upon us to do this in a manner that's responsible, judicious and accounts for the emerging understanding of the safety profile and I think we're doing that by ensuring that our phase three is a large phase three."
Public health officials say there is no returning to "normal" until there is a vaccine. There are no FDA-approved drugs or vaccines for the coronavirus, which has infected more than 13 million people worldwide and killed at least 578,600 as of Wednesday, according to data compiled by Johns Hopkins University.
Moderna's experimental vaccine contains genetic material called messenger RNA, or mRNA, which scientists hope provokes the immune system to fight the virus. The new data is boosting hopes that there could be a safe and effective vaccine to prevent Covid-19 by the end of the year or early 2021.
In the early-stage trial, which was run by the National Institutes of Health, each participant received a 25, 100 or 250 microgram dose of the vaccine candidate, with 15 people in each dose group. Participants received two doses of the potential vaccine. No serious side effects were reported, but more than half of the participants reported mild or moderate symptoms such as fatigue, muscle aches or pain at the injection site, according to the data.
Moderna announced on Tuesday it will begin its late-stage trial for its vaccine on July 27. The trial will enroll 30,000 participants across 87 locations, according to ClinicalTrials.gov. Participants in the experimental arm will receive a 100 microgram dose of the potential vaccine on the first day and another 29 days later. Some patients in the trial will also receive a placebo
The effort by Moderna is one of several working on a potential vaccine for Covid-19. More than 100 vaccines are under development globally, according to the World Health Organization. At least 23 are already in human trials, according to the WHO.
Earlier this month, pharmaceutical giant Pfizer, alongside German drugmaker BioNTech, released positive results from its closely watched early-stage human trial of a coronavirus vaccine. The company said its vaccine produced neutralizing antibodies in all participants who received two of the 10 or 30 microgram doses after 28 days, according to the preliminary data. It said the levels of neutralizing antibodies were 1.8 to 2.8 times higher than in recovered Covid-19 patients.
While Moderna and Pfizer's results are promising, scientists warn that questions remain about how the human body responds once it's been infected with the virus. The answers, they say, may have important implications for vaccine development, including how quickly it can be deployed to the public.
One critical question among scientists is whether antibodies produced in response to Covid-19 offer protection against getting infected again.
Scientists hope the antibodies provide some degree of protection against getting Covid-19, but they can't say that definitively yet since the virus was first discovered just six months ago. It hasn't been studied in-depth and some patients appear to have been reinfected after recovering from Covid-19.
"I would say there's a lot of optimism," said Dr. Jonathan Abraham, a professor at Harvard Medical School's Department of Microbiology and Immunobiology. "But I think the optimism is making a lot of assumptions. The assumptions include that what we're seeing now is a type of infection where if you get infected and you're reexposed shortly after that you won't be infected again."
Additionally, a recent study published in Nature Medicine found coronavirus antibodies may last only two to three months after a person becomes infected with Covid-19. Researchers examined 37 asymptomatic people, those who never developed symptoms, in the Wanzhou district of China. They compared their antibody response to that of 37 people with symptoms.
Dr. Anthony Fauci, the top U.S. infectious disease expert, has often touted Moderna's potential vaccine. On Monday, he said he's "cautiously optimistic" scientists will be able to create at least one safe and effective vaccine by the end of the year or early 2021.
While questions remain, Zaks said Wednesday that scientists have learned about the virus from its coronavirus relatives SARS and MERS. The spike protein, which the virus uses to enter the host cell, is a critical piece for the vaccine development, he said.