Coronavirus vaccine trial results : Moderna mRNA-1273 shows early promise

Moderna said that mRNA-1273, its novel coronavirus vaccine candidate, has delivered positive interim data in a phase 1 clinical trial by eliciting neutralizing antibody titer levels in all eight initial participants across the 25 µg and 100 µg dose cohorts.

The early-stage clinical trial in humans was led by the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

Moderna said that mRNA-1273 was found to be generally safe and well-tolerated during the COVID-19 vaccine clinical trial.

Commenting on the coronavirus vaccine trial results, Tal Zaks – Chief Medical Officer at Moderna said: “These interim Phase 1 data, while early, 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 µg.

“When combined with the success in preventing viral replication in the lungs of a pre-clinical challenge model at a dose that elicited similar levels of neutralizing antibodies, these data substantiate our belief that mRNA-1273 has the potential to prevent COVID-19 disease and advance our ability to select a dose for pivotal trials.”

Currently, immunogenicity data are available for the 25 µg and 100 µg dose level (ages 18-55) following two doses (day 43) and at the 250 µg level (ages 18-55) after giving one dose (day 29), according to Moderna. The US biotech company said that dose-dependent increases in immunogenicity were noted across the three dose levels, and between prime and boost within the 25 µg and 100 µg dose levels.

All participants ages 18-55 (n=15 per cohort) in the coronavirus vaccine trial, across all three dose levels seroconverted by day 15 following a single dose. At day 43, a couple of weeks after the second dose, at the 25 µg dose level (n=15), levels of binding antibodies were at the levels observed in convalescent sera (blood samples from patients who have recovered from COVID-19) tested in the same assay.

At day 43, at the 100 µg dose level (n=10), levels of binding antibodies surpassed the levels seen in convalescent sera by a significant extent. Moderna said that samples are yet to be available for remaining participants.

The California-based clinical-stage company said that based on the interim data from the phase 1 trial, the phase 2 study of the coronavirus vaccine candidate, which will be led by Moderna, will be amended to evaluate two dose levels – 50 µg and 100 µg, with an objective of finalizing a dose for pivotal studies.

The company said that the NIAID-led phase 1 study is being amended to include a 50 µg dose level cohort across all the three age groups.

Moderna expects the dose for the phase 3 clinical trial to be between 25 µg and 100 µg and anticipates phase 3 trial to be initiated in July, subject to finalization of the clinical trial protocol.

Stéphane Bancel – CEO of Moderna, commenting on the coronavirus vaccine trial results, said: “With today’s positive interim Phase 1 data and the positive data in the mouse challenge model, the Moderna team continues to focus on moving as fast as safely possible to start our pivotal Phase 3 study in July and, if successful, file a BLA.

“We are investing to scale up manufacturing so we can maximize the number of doses we can produce to help protect as many people as we can from SARS-CoV-2.”