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Moderna (MRNA) soared a further 16% in Tuesday’s after-market trading after the biotech announced the publication of an interim analysis of the open-label Phase 1 study of mRNA-1273, its vaccine candidate against COVID-19.
Results reaffirmed positive interim data assessment announced on May 18, said Moderna, and show mRNA-1273 induced rapid and strong immune responses against SARS-CoV-2. Neutralizing antibodies were observed in 100% of evaluated participants at the 100 µg dose level selected for the upcoming Phase 3 trial.
Published in The New England Journal of Medicine, the interim analysis evaluated a two-dose vaccination schedule of mRNA-1273 given 28 days apart across three dose levels (25, 100, 250 µg) in 45 healthy adult participants ages 18-55 years, and reported results through Day 57.
The study was led by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).
“These Phase 1 data demonstrate that vaccination with mRNA-1273 elicits a robust immune response across all dose levels and clearly support the choice of 100 µg in a prime and boost regimen as the optimal dose for the Phase 3 study,” said Tal Zaks CMO of Moderna. “We look forward to beginning our Phase 3 study of mRNA-1273 this month to demonstrate our vaccine’s ability to significantly reduce the risk of COVID-19 disease.”
Encouragingly, mRNA-1273 was generally safe and well-tolerated, with no serious adverse events reported through Day 57. Adverse events (AEs) were generally transient and mild to moderate in severity.
mRNA-1273 induced binding antibodies to the full-length SARS-CoV-2 Spike protein (S) in all participants after the first vaccination, with all participants seroconverting by Day 15. This is the time period during which a specific antibody develops and becomes detectable in the blood.
After two vaccinations, mRNA-1273 elicited robust neutralizing antibody titers. At Day 43, neutralizing activity against SARS-CoV-2 (PRNT80) was seen in all evaluated participants. At the Phase 3 selected dose of 100 µg, the geometric mean titer levels were 4.1-fold above those seen in reference convalescent sera (n=3).
Evaluation of the durability of immune responses is ongoing, and participants will be followed for one year after the second vaccination, with scheduled blood collections throughout that period.
With the Phase 3 dose being finalized at 100 μg, Moderna says it remains on track to be able to deliver approximately 500 million doses per year, and possibly up to 1 billion doses per year, beginning in 2021, due to collaborations with Lonza, Catalent and ROVI.