Moderna's mRNA COVID-19 vaccine 94.1% effective at final analysis

Moderna announced Monday that the primary efficacy analysis of the Phase III COVE study showed that the COVID-19 vaccine mRNA-1273 had an efficacy rate of 94.1%, confirming the level observed at the first interim analysis about two weeks ago. The company, whose shares shot up as much as 17% on the news, noted that the latest data were based on 196 cases of coronavirus infection, with 185 recorded in the placebo group versus 11 among those immunised with its experimental mRNA-based candidate.

According to Moderna, the analysis included 30 severe cases of COVID-19, all of which occurred in the placebo arm. In addition, there has been one COVID-19-related death in the study to date, and this occurred in the placebo group as well. Meanwhile, results showed that efficacy was consistent across age, race and ethnicity, and gender demographics. Moderna noted that among the 196 coronavirus cases, 33 cases were in older adults over 65.

Changing course of pandemic

"We believe that our vaccine will provide a new and powerful tool that may change the course of this pandemic and help prevent severe disease, hospitalisations and death," remarked CEO Stéphane Bancel.

The trial, initiated in July, has recruited more than 30,000 adults in the US, with medically high-risk participants comprising 42% of the study population. These include more than 7000 people over age 65, as well as individuals with chronic diseases that put them at increased risk of severe COVID-19, such as diabetes, severe obesity and cardiac disease. The trial's primary endpoint is based on the analysis of COVID-19 cases confirmed and adjudicated starting two weeks following the second dose of vaccine.

Regulatory requests in US, EU

Chief medical officer Tal Zaks said "this is as black and white as an effect on a population will be. Your chances of actually being sick if you've been vaccinated are decreased 20-fold." Zaks noted that while the vaccine caused significant influenza-like symptoms in some participants, this "goes hand-in-hand with having such a potent vaccine," but it has not led to any significant safety concerns so far. The most common solicited adverse reactions, which tended to increase in frequency and severity after the second dose, included injection-site pain, fatigue, myalgia, arthralgia and headache.

Moderna said COVE has surpassed the post vaccination median follow-up of two months that the FDA requires for an emergency-use authorisation (EUA). Based on the results, the company plans to request an EUA from the US regulator, with an FDA advisory committee meeting to review mRNA-1273 likely to be held on December 17. Moderna also intends to seek conditional approval from the European Medicines Agency, which has been assessing mRNA-1273 as new data become available via a rolling review process that started in mid-November.

"We will file today for an [EUA] and continue forging ahead with the rolling reviews that have already been initiated with several regulatory agencies around the globe," including Health Canada, SwissMedic and the UK's Medicines and Healthcare products Regulatory Agency, Bancel said.

Pfizer, BioNTech already filed

Pfizer and partner BioNTech have already filed for US emergency use of their mRNA-based vaccine candidate BNT162b2 after a final analysis of 170 COVID-19 cases showed an efficacy rate of 95%. AstraZeneca also recently released interim findings for its adenovirus vector-based COVID-19 vaccine AZD1222, co-developed with the University of Oxford, although the drugmaker is likely to conduct an additional trial to clear up questions surrounding its efficacy.

Meanwhile, Moderna anticipates that shipping of mRNA-1273 to designated distribution points throughout the US will occur shortly after an EUA is granted, adding that it is on track to have about 20 million doses of its vaccine ready to ship in the US by year-end. Zaks also indicated that Moderna plans to start a new trial to test mRNA-1273 in adolescents before the end of 2020, followed by another study in even younger volunteers early in 2021, with the company hoping to have the vaccine available for adolescents by September of next year.

For related analysis, see Physician Views results: Clinical benchmark set high by mRNA COVID-19 vaccines, and ViewPoints: Two is a vital trend towards normalcy with COVID-19 vaccines.

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