The first US Covid-19 vaccine trial has shown positive results, after Moderna reported that its potential vaccine boosted the immune system of participants to the same or higher levels of protection as patients who had recovered from the disease.
The Boston-based biotech company announced the interim results from the early stage trial on Monday morning, showing that the vaccine candidate known as mRNA-1273 was safe and well tolerated by participants, with only minor side effects.
Stéphane Bancel, Moderna’s chief executive, said he could not have expected better data.
The news boosted sentiment on Wall Street, where futures in the S&P 500 US benchmark equity index gained 2.8 per cent. Shares in Moderna jumped by almost a third to $88.50 in pre-market trading in New York.
Recent market moves have been accentuated by hopes for coronavirus treatments. In April, positive data that an antiviral drug made by Californian drugmaker Gilead might be able to help patients recover more quickly lifted the S&P 500 to close almost 2 per cent higher.
Moderna was the first US company to put a vaccine into human trials, racing after the receipt of the genetic code of the vaccine to create the first vials in just 42 days.
Its messengerRNA approach allows it to effectively programme a vaccine — but a vaccine using this method has not yet been approved by any regulator.
There were just 45 participants for the early stage, and the data on antibodies was only available for eight of those.
The study participants, aged between 18 and 55, received two doses of the vaccine. Two weeks following the second dose, those on the lowest dose showed the same level of antibodies seen in recovered patients. The group on an increased dose showed higher levels.
“I’m really thrilled,” Mr Bancel told the Financial Times. “What is really special about mRNA technology is we have pushed it to a place where more antibodies are made than a natural infection so it should provide a long immunity.”
He believed Moderna could start a large phase three trial in July, as the phase two trial was starting shortly. The third trial will need to include thousands of participants, to demonstrate safety and efficacy across a large population.
Mr Bancel said even if the vaccine showed an efficacy rate as low as 60 or 70 per cent, it could be useful in stopping the replication rate of the virus. The third trial would probably be conducted at sites around the world, as it was hard to predict where an outbreak of Covid-19 would occur at that time.
That larger final trial could give results by the end of the year. Mr Bancel said regulators were moving fast and pointed to recent comments by US health secretary, Alex Azar, that a vaccine could be approved by the end of the year.
Unlike most vaccines, which show the body’s immune system an attenuated version of the virus, messengerRNA translates a protein from the virus into human cells and shows it to the B cells that secrete antibodies. Antibodies wane over time, so the more antibodies that are created at the start, the more likely that they remain effective for longer.
Tal Zaks, Moderna chief medical officer, said the results showed that even lower doses elicited an “immune response of the magnitude caused by natural infection”.
The results — plus data from a study in mice — have allowed Moderna to focus the next trials on the lower end of the dose scale.
Side effects in the early phase of the trial were those that common for many vaccines: some people experience redness at the site of injection and chills.
“These data substantiate our belief that mRNA-1273 has the potential to prevent COVID-19 disease,” he said.