American biotech Modern, one of the world leaders In the race to get a vaccine against COVID-19, he announced Tuesday the publication of an interim analysis of the phase I study of his candidate mRNA-1273. The results of the work, led by the National Institute of Allergy and Infectious Diseases (NIAID) in the US, have been published in The New England Journal of Medicine.
According to the study, the first patient received the experimental vaccine on March 16. In total, in this first phase, three groups of 15 healthy adult participants aged 18-55 years (45 people) received two intramuscular injections of mRNA-1273 at 28 days apart at three dose levels (25, 100, 250 µg ). Vaccination results were observed until day 57.
Like ya advance the US firm in May, the vaccine showed safety and tolerance in the doses participants received, as well as rapid and strong immune responses against SARS-CoV-2. The candidate is based on the use of messenger RNA (mRNA) technology. Once injected into the body, it sends the message to cells to make virus-like proteins, which are activated and function as antibodies.
Regarding safety, after the first injection, the volunteers did not find any serious adverse effects, only fatigue, headache, chills, myalgia or pain at the vaccination site. Systemic side effects were more common in the second vaccination and in those who received the highest doses.
Fast and strong immune response
Regarding the neutralizing activity induced by the vaccine, the published interim analysis now includes test results up to day 43 after the second injection.
The two doses generated high levels of neutralizing antibody activity above the average values observed in the convalescent sera (they carry antibodies from recovered patients) obtained from 38 individuals with a confirmed diagnosis of COVID-19. At day 57, the 100 µg doses were 2.1 times higher than those observed in these convalescent sera.
“These phase I data demonstrate that vaccination with mRNA-1273 elicits a robust immune response at all dose levels and clearly supports the choice of 100 µg in an optimal and booster regimen as the appropriate dose for the phase 3 study. “explains Tal Zaks, medical director of Moderna.
Assessment of the durability of immune responses is still ongoing, and participants will be followed for one year after the second vaccination, with blood samples scheduled throughout the period.
In April, the trial was expanded to enroll adults 55 and older. Currently, it has 120 participants. But the results now published only cover the age group of 18 to 55 years.
“These positive Phase I data are encouraging and represent an important step forward in the clinical development of mRNA-1273, our candidate for the COVID-19 vaccine,” says Stéphane Bancel, CEO of Moderna.
A phase 2 clinical trial of mRNA-1273 began in late May and phase III is expected to be launched later this month with about 30,000 volunteers. “We hope to start our phase III study of mRNA-1273 this month and demonstrate the ability of our vaccine to significantly reduce the risk of COVID-19,” continues Bancel.
“We are committed to advancing your clinical development as quickly and safely as possible while investing to scale up your manufacturing and address this global health emergency,” concludes the executive director.
The shares of the firm fell 7% earlier in the month after the medical news agency STAT will report a delay in this large trial, due to changes that Moderna wants to introduce in its study plan. But the company still believes it will be able to start testing this month.