Moderna announced longer-term data Tuesday from the phase 3 trial used to support authorizations of its coronavirus vaccine mRNA-1272, saying the vaccine continues to show more than 90% efficacy against cases of COVID-19, including 95% protection from severe disease, a median 6 months after the second dose. The company also unveiled new preclinical findings indicating that its variant-specific booster vaccine candidates increase neutralizing titers against SARS-CoV-2 variants of concern, including one that more specifically targets the B.1.351 variant first identified in South Africa.
The news follows antibody persistence data for mRNA-1272 out to 6 months that were recently published in the NEJM. The pivotal COVE study, which had randomized more than 30,000 adults to receive either mRNA-1273 or placebo, showed that Moderna’s vaccine had an efficacy rate of 94.1% at preventing infections 14 days after the second dose. The latest analysis is based on over 900 cases of COVID-19 in the COVE study as of April 9, including over 100 cases of severe disease. The company did not specify how many study volunteers in each group contracted the infection.
Consistent 6-month data for mRNA vaccines
Moderna’s disclosure comes shortly after Pfizer and BioNTech released updated results from a pivotal phase 3 study showing that their COVID-19 vaccine BNT162b2 was 91.3% effective at preventing the disease up to 6 months after the second dose. Meanwhile, BNT162b2 was associated with an efficacy rate against severe illness of 100%, as defined by the US Centers for Disease Control and Prevention, or 95.3%, as defined by the FDA.
Moderna noted that as of Tuesday, all placebo participants in the COVE trial have been offered mRNA-1273 and 98% have received the vaccine. The study remains ongoing, with Moderna saying it plans to share updated results including efficacy against asymptomatic infection, genotyping data and information regarding potential correlates of protection. The company is also conducting phase 2/3 testing in paediatric populations, including the TeenCOVE trial in adolescents aged 12 to 17 years, and the KidCOVE study in children aged 6 months to 11 years.
Work against variants progresses
Meanwhile, new preclinical data have also been submitted as a preprint to bioRxiv regarding Moderna’s mRNA-1273.351 candidate, which more specifically targets the B.1.351 variant, and a multivalent booster candidate, dubbed mRNA-1273.211, which combines its currently authorized mRNA-1273 vaccine with mRNA-1273.351 in a single shot. According to Moderna, the multivalent version provided the “broadest level of immunity,” while a boost with mRNA-1273.351 at 6 months “closed the neutralizing titer gap” for variants of concern, resulting in comparable titer levels between the ancestral SARS-CoV-2 strain and B.1.351. A mid-stage trial evaluating three approaches to boosting is ongoing.
“The new preclinical data on our variant-specific vaccine candidates give us confidence that we can proactively address emerging variants,” commented CEO Stéphane Bancel, adding “Moderna will make as many updates to our COVID-19 vaccine as necessary until the pandemic is under control.”
Earlier in the day, Moderna also affirmed that based on a review of more than 64.5 million mRNA-1273 doses administered globally, its inoculation has not been tied to cerebral venous sinus thrombosis or other thrombotic events that have recently led to safety concerns with AstraZeneca and Johnson & Johnson’s vaccines.
Meanwhile, in a supply update, Moderna said it has so far delivered 132 million doses globally as of April 12, including roughly 117 million to US and 15 million delivered from its supply chain outside the country. The drugmaker added that it remains on track to ship the second 100 million doses it is contracted to deliver to the US government by end of May, followed by another 100 million by the end of July. It noted that the ex-US supply chain, which was set up about one quarter behind the US one, “continues to ramp up.”