Moderna has announced that its Phase II/III study of its Covid-19 vaccine (mRNA-1273) in adolescents has met its primary immunogenicity endpoint, successfully bridging immune responses to the adult vaccination.
In the study, no cases of Covid-19 were observed in participants who had received two doses of the Moderna Covid-19 vaccine. In addition, a vaccine efficacy of 93% in seronegative participants was observed starting 14 days after the first dose using the secondary CDC case definition of Covid-19, which tested for milder disease.
This study, known as the TeenCOVE study, enrolled more than 3,700 participants ages 12 to less than 18 years in the US. The company plans to submit these data to regulators globally in early June.
“We are encouraged that mRNA-1273 was highly effective at preventing Covid-19 in adolescents. It is particularly exciting to see that the Moderna Covid-19 vaccine can prevent SARS-CoV-2 infection,” said Stéphane Bancel, Chief Executive Officer of Moderna. “We will submit these results to the U.S. FDA and regulators globally in early June and request authorisation. We remain committed to doing our part to help end the Covid-19 pandemic.”
In this Phase II/III study, adolescent participants ages 12 to less than 18 years were enrolled and randomised 2:1 to two 100 µg doses of mRNA-1273 or placebo. The primary endpoint of non-inferior immunogenicity versus the Phase III adult study comparator group was met. After two doses, no cases of Covid-19 were observed in the vaccine group using the case definition from the adult Phase III COVE study, compared to four cases in the placebo group, resulting in a vaccine efficacy of 100% starting 14 days after the second dose.
No significant safety concerns have been identified to date. Most adverse events were mild or moderate in severity. The most common solicited local adverse event was injection site pain. The most common solicited systemic adverse events after the second dose were headache, fatigue, myalgia and chills.
Image credit: Alexis Brown