Positive Trial Data for Moderna’s COVID-19 Vaccine Candidate

Moderna recently announced positive clinical data for its vaccine candidate, mRNA-1273, from the Phase I study, led by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

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mRNA-1273 was safe and well-tolerated, with results consistent with prior Moderna infectious disease vaccine clinical studies, said the biotechnology company pioneers in messenger RNA therapeutics and vaccines.

All participants, aged 18 to 55, received a 25 µg, 100 µg, or 250 µg, with 15 people in each dose group. Participants received two doses of the vaccine about 28 days apart. 

The vaccine-induced neutralizing antibodies in all eight-study participants, as measured by plaque reduction neutralization (PRNT) assays against live SARS-CoV-2.  

The levels of neutralizing antibodies at day 43 were at or above levels normally seen in blood samples from those who have recovered from COVID-19. Those who received 100 µg had antibodies that “significantly exceeded levels” in recovered patients. Data on a second dose was not available for the 250 µg, 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,” Tal Zaks, MD, PhD, chief medical officer at Moderna, said in the announcement. 

“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.”

The only adverse event found in the clinical trial was a single participant receiving 100 µg of the COVID-19 vaccine candidate experienced grade 3 erythema around the injection site. 

Researchers stated that the most notable adverse events were seen at the 250-µg dose level where three participants saw grade 3 systemic symptoms. No grade 4 adverse events or serious adverse events were reported.

“With today’s positive interim Phase I 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,” said Stéphane Bancel, chief executive officer at Moderna. 

“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.”

Moderna said that the Phase 2 study will be changed to study two dose levels, 50 µg and 100 µg, with the goal to select a dose for pivotal studies. Moderna anticipates the dose for the Phase 3 study to be between 25 µg and 100 µg and expects Phase 3 trial initiation in July 2020.

Funding from the Biomedical Advanced Research and Development Authority (BARDA), part of HHS, supported the planning for the Phase 2 and Phase 3 studies of mRNA-1273. 

At the end of April, Moderna received $483 million from BARDA to boost testing of mRNA-1273. The funding supported the late-stage clinical development programs and boost mRNA-1273 manufacturing throughout this year.

“We are thankful for BARDA’s support to fund the accelerated development of mRNA-1273, our vaccine candidate against SARS-CoV-2,” said Stéphane Bancel, Moderna’s chief executive officer. 

“Time is of the essence to provide a vaccine against this pandemic virus. By investing now in our manufacturing process scale-up to enable large scale production for pandemic response, we believe that we would be able to supply millions of doses per month in 2020 and with further investments, tens of millions per month in 2021, if the vaccine candidate is successful in the clinic.”