Moderna's COVID-19 vaccine shows early promise

Promising early results Monday from human trials of a vaccine for COVID-19.

The pharmaceutical company Moderna said its experimental vaccine produced antibodies that could "neutralize" the new coronavirus in patients in a small early stage clinical trial.

The news sent the firm's shares up 25% in early trading

Dr. Stephen Hoge is the firm president, and he spoke to CBS News Monday morning about the phase one trial.

"All subjects who had received two doses of our vaccine in the first two dose-level cohorts - that's at 25 microgram, a low-does, and a 100 microgram, our mid dose - had sero-converted to develop antibodies in their blood that bound the virus."

Early results from a study by the U.S. National Institues of health showed antibody levels similar to those in blood samples from people who had recovered from COVID-19.

"All together, we're very pleased by that result because it suggests we're on the right path with this vaccine."

The drugmaker said the vaccine, mRNA-1273, was also found to be generally safe and well tolerated in the early-stage study.

Hoge said the phase one test was conducted in 45 subjects, and primary focused on the safety of human trials. Phase two will entail a larger test pool.

"And so we'll be looking across 600 people in the phase two study, which will start any day now, and that will be to both confirm that we've got the right idea of the dose, where we believe we will see protective immunity, as well as, that the safety profile continues to hold up."

Dr. Anthony Fauci, the top U.S. infectious diseases expert, last week told Congress the Moderna trial was just one of several currently in development.

"There are at least eight candidate COVID-19 vaccines in clinical development. I will describe one very briefly, which is not the only one, but one that we have been involved in heavily developing with Moderna (Therapeutrics). It's a messenger RNA (ribonucleic acid) platform."

Moderna leads global efforts in developing a vaccine for the new coronavirus and last week, won the U.S. health agency's "fast track" label to speed up the regulatory review. It is looking to begin late-stage trials in July.