Moderna’s COVID-19 Vaccine Shows Promise in Early Trial Results

May 19, 2020

Moderna has reported positive early results from a phase 1 trial of its COVID-19 vaccine candidate, mRNA-1273, with all participants producing antibodies to the virus within 15 days of a single dose. It hopes to launch a phase 3 trial in July in an extremely expedited time frame.

Patients who received two doses at 100 mcg had levels of antibodies that exceeded those seen in convalescent plasma from recovered patients.

Participants given the lower dose of 25 mcg had levels of antibodies equivalent to those seen in convalescent plasma from COVID-19 survivors.

The interim data “demonstrate that vaccination with mRNA-1273 elicits an immune response of the magnitude caused by natural infection starting with a dose as low as 25 mcg,” said Tal Zaks, Moderna’s chief medical officer.

The NIH’s National Institutes of Allergy and Infectious Diseases initially tested the vaccine in 45 healthy adults aged 18 to 55 years old at 25 mcg, 100 mcg and 250 mcg doses. The trial was later amended to add cohorts aged 56 to 70 years old, and another aged 71 and older.

Three participants given 250 mcg doses of the vaccine experienced adverse events following a second dose.

Based on the interim results, the phase 1 trial will be amended to include a 50 mcg cohort across the three age groups. The phase 2 study will be amended to include dosage levels of 50 mcg and 100 mcg (DID, May 13).

The company anticipates testing a dose between 25 mcg and 100 mcg in a phase 3 trial, which it hopes to start in July. — Jordan Williams