Moderna Inc. (MRNA) on Tuesday reported "positive interim results" from a late-stage study of what it calls the "next-generation COVID-19 vaccine."

The biotech firm reported that a Phase 3 trial of its mRNA-1283 shot met its primary endpoints, and showed a higher immune response to both the original and Omicron versions of the SARS-CoV-2 virus than Moderna’s current vaccine, mRNA-1273.222, known by the brand name Spikevax.

The company added that the trial drug's effect was more acutely noted in those 65 years old and up, the age group most at risk of serious illness from COVID-19. In addition, mRNA-1283 has a longer shelf life and comes in pre-filled syringes, making it easier for healthcare providers to use.

Chief Executive Officer (CEO) Stephane Bancel explained that mRNA-1283 is a “critical component” of its planned combined COVID-19-influenza shot, noting that this study “gives us confidence in our ability to bring this much-needed vaccine to market.”

Shares of Moderna initially rose after the opening bell Tuesday but had slipped about 2.5% to $107.62 as of 1:45 p.m. ET. The stock has risen since the company posted a surprise profit last month but remains down slightly year-to-date and has lost more than 28% of its value in the last 12 months.