Moderna says mRNA COVID-19 vaccine 94.5% effective

Moderna on Monday reported that its experimental COVID-19 vaccine mRNA-1273 showed an efficacy rate of 94.5% in the first interim analysis of the Phase III COVE study. The company, whose shares were up as much as 16% on the news, noted that the analysis was based on 95 cases of coronavirus infection, of which 90 cases were observed in the placebo group versus five in the mRNA-1273 group.

CEO Stéphane Bancel called the results a "pivotal moment," adding that "this positive interim analysis…has given us the first clinical validation that our vaccine can prevent COVID-19 disease, including severe disease." The drugmaker indicated that it plans to seek emergency-use authorisation from the FDA in the coming weeks, with the filing set to be based on the final analysis of 151 cases and a median follow-up of more than two months.

The latest findings follow the release last week of a first look at Phase III data for Pfizer and BioNTech's mRNA vaccine BNT162b2, which demonstrated more than 90% efficacy at preventing COVID-19 in participants without evidence of prior SARS-CoV-2 infection (for related analysis, see ViewPoints: Pfizer's COVID success resets the vaccine competition). Russian researchers also reported Phase III interim results showing an efficacy rate of 92% for Sputnik V, an adenoviral vector-based COVID-19 vaccine developed at the Gamaleya Institute.

Prevents severe disease

Moderna's vaccine encodes for a prefusion stabilised form of the SARS-CoV-2 spike protein. The COVE study is testing mRNA-1273 at the 100-mcg dose level in 30,000 participants in the US, ages 18 and older. The company said 42% of the study population falls into medically high-risk groups, including advanced age and comorbidities such as diabetes, severe obesity and cardiac disease. Subjects were randomised to receive two doses of mRNA-1273, administered 28 days apart, or placebo. The trial's primary endpoint is the prevention of symptomatic COVID-19 disease, while key secondary goals include prevention of severe COVID-19 disease and prevention of infection by SARS-CoV-2.

Moderna noted that the independent data safety monitoring board informed it that COVE met the statistical criteria pre-specified in the study protocol for efficacy. The company added that for one of the secondary goals, 11 cases of severe COVID-19 were seen at the first interim analysis, all of which occurred in the placebo group. The drugmaker added that a review of available safety data "did not report any significant…concerns." Interim Phase I study data has shown that mRNA-1273 induced anti-SARS-CoV-2 immune responses, including neutralising antibodies and T-cell responses, in participants aged 18 to 55 years as well as in older adults.

Ready to ship

Moderna, which is developing mRNA-1273 as part of the US government's Operation Warp Speed programme, expects to produce about 20 million doses for the country this year, with millions of these doses already manufactured. "Assuming we get an emergency-use authorisation, we'll be ready to ship through Warp Speed almost in hours," Moderna president Stephen Hoge said, adding "so it could start being distributed instantly."

Moreover, mRNA-1273 can be stored for up to six months at -20 degrees Celsius, and it is stable in a normal fridge at temperatures of between 2 degrees Celsius and 8 degrees Celsius for 30 days, which means the company "can use existing distribution methods," chief medical officer Tal Zaks said recently. By contrast, Pfizer and BioNTech's BNT162b2 must be kept at ultra-low temperatures, posing a number of challenges for storage and distribution.

Meanwhile, Moderna said it would also use its data to seek authorisation in Europe and other regions. On Monday, the European Medicines Agency launched a rolling review of mRNA-1273 following similar regulatory actions for BNT162b2, as well as AstraZeneca's AZD1222, for which late-stage trial results have yet to be released. An EU official indicated that the European Commission wants to reach a deal with Moderna for the supply of millions of doses of mRNA-1273 for a price below $25 per dose.

Regulators in the UK and in Switzerland are also conducting their own rolling reviews of Moderna's candidate. On Monday, the UK government  announced that it had secured 5 million doses of mRNA-1273, adding that if the vaccine meets safety and effectiveness goals, and is approved by the medicines regulator, it could be delivered to the UK as early as next spring with the potential for the government to procure more doses next year.


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