Novavax Inc. shares jumped more than 15% in after-hours trading Thursday, after the company revealed results of studies that showed its proposed COVID-19 vaccine is nearly 90% effective overall, but much less effective against a new variant.
In a phase 3 trial in the UK, the Novavax
vaccine showed 89.3% overall efficacy, but lesser protection against new variants. Novavax disclosed that the original the vaccine was 95.6% effective against the most common form of COVID-19 and 85.6% effective against the new strain originally identified in the UK.
A phase 2b trial in South Africa showed that the vaccine was slightly less than 50% effective against a new variant originally identified in that country. After the 49.4% efficacy against the new variant led to an overall number of 60% in that trial, Novavax said it would begin developing a new vaccine specifically aimed at that variant, which was found in the U.S. for the first time Thursday.
“A primary benefit of our adjuvanted platform is that it uses a very small amount of antigen, enabling the rapid creation and large-scale production of combination vaccine candidates that could potentially address multiple circulating strains of COVID-19,” Novavax’s president of research and development, Gregory Glenn, said in Thursday’s announcement. “Combined with the safety profile that has been observed in our studies to-date with our COVID-19 vaccine, as well as prior studies in influenza, we are optimistic about our ability to rapidly adapt to evolving conditions.”
Shares originally dove more than 10% in after-hours trading following release of the news, but soon turned around and were up more than 20%. The stock gained 2.2% in regular trading Thursday, and has gained more than 1,700% in the past year, as the S&P 500 index
has increased 14.5%.
Novavax is still conducting additional studies in the U.S. and Mexico. Executives planned to discuss the results further in a conference call at 4:30 p.m. Eastern time Thursday.