Sanofi (NASDAQ:SNY) has a new COVID-19 vaccine candidate ready to start clinical trials in humans. On Thursday, it reported that MRT5500, which was discovered by Translate Bio (NASDAQ:TBIO), induced antibodies to the coronavirus in mice and nonhuman primates. The vaccine also induced a T cell response.

MRT5500 is a messenger RNA (mRNA) vaccine candidate, similar to the candidates being developed by Moderna and the Pfizer/BioNTech collaboration. Using mRNA in vaccines is a new technology and as yet, no mRNA vaccines for any conditions have been approved by the FDA.

Blue gloved hand holding bottle of COVID-19 vaccine

Image source: Getty Images

Other mRNA vaccine candidates for COVID-19 came out of their initial development stages quickly. Moderna was able to start a phase 1 trial for its vaccine candidate on March 16. Pfizer and BioNTech got their coronavirus candidate into human trials on April 29. Both are now in phase 3 trials. 

The process for Sanofi and Translate Bio has been slower. In March, the companies expanded their existing partnership to include finding a COVID-19 mRNA vaccine candidate. In June, Sanofi gave Translate Bio $425 million to expand that partnership yet again. Now, their vaccine is finally ready to start human trials.

Concurrently, Sanofi pursued another COVID-19 vaccine candidate in collaboration with Glaxo. That one is a "classic" vaccine, similar to the candidate being tested by Novavax. It's a recombinant protein vaccine, delivered in combination with an adjuvant designed to induce a stronger immune response. It's currently in phase 1/2 trials.

So while Sanofi is trailing in the race to bring a COVID-19 vaccine to market, it now has two different candidates that could eventually cross the finish line. The stock was down by 2.6% in mid-afternoon trading Thursday.

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