Moderna interim analysis shows promising immune response results from COVID-19 vaccine candidate

Moderna, Inc. expects to begin a 30,000 participant phase 3 study of its COVID-19 vaccine candidate later this month, following the publication of an interim phase 1 analysis that demonstrated a generally safe and well-tolerated reaction among a small group of healthy adults.

The results, published in the New England Journal of Medicine, stemmed from a two-dose schedule of the candidate — mRNA-1273 — at three dose levels, spread a month apart. In all, 45 participants between the ages of 18 and 55 years old were dosed. All volunteers developed neutralizing antibodies as a result of the doses.

“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,” Dr. Tal Zaks, Chief Medical Officer of Moderna, said. “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.”

The study was conducted by the National Institute of Allergy and Infectious Diseases (NIAID), which is jointly developing the vaccine with Moderna, and led by Dr. Lisa Jackson of the Kaiser Permanente Washington Health Research Institute in Seattle. The phase 3 study is expected to begin on July 27.

While results were strong and quickly induced, the report also showed that no serious adverse side effects emerged throughout treatment. However, the few side effects that impacted more than half of volunteers included symptoms like fatigue, chills, headaches, and pain at the injection site.

This test was focused on younger adults, though, for a disease that has disproportionately impacted the elderly and immunocompromised. Moderna acknowledged that fact. Additional cohorts have been enrolled in the phase 1 study — though not included in this report — that include older volunteers. A now fully enrolled phase 2 study also accounts for this, being split into a group of 300 younger adults and 300 older adults.

For the phase 3 study, participants will be subjected to a randomized, placebo-controlled trial. Researchers will look for the candidate’s ability to prevent symptomatic cases of COVID-19. They will also seek prevention of severe COVID-19 disease and prevention of infection by the virus, which causes it, SARS-CoV-2. Modern has already completed the manufacture of the vaccine necessary to start that study, and should be able to deliver approximately 500 million doses per year beginning in 2021.