Moderna RSV vaccine is 83.7% effective in Phase 3 trial

Moderna is edging closer to launching a new investigational mRNA vaccine to fight the respiratory syncytial virus (RSV), which was 83.7% effective at preventing infection in a Phase 3 trial.

The Boston biotech company revealed Wednesday that “positive topline data from its ConquerRSV Phase 3 pivotal efficacy trial of mRNA-1345” achieved primary efficacy endpoints in people ages 60 and older.

“The other primary efficacy endpoint against RSV-LRTD defined by three or more symptoms was also met, with a VE of 82.4%. The trial is ongoing, and additional efficacy analyses are planned as cases accrue, including for severe RSV,” the release adds.

According to Moderna, no safety concerns have been identified during its “placebo-controlled study of approximately 37,000 adults 60 years or older in 22 countries.” The company plans to publish the safety and efficacy data from the trial in a peer-reviewed journal.

The company, a member of the Biotechnology Innovation Organization (BIO), plans to apply for approval by the U.S. Food and Drug Administration (FDS), per Moderna’s chief medical officer, Dr. Paul Burton.

“We would hope that we would have approvals really by the end of 2023 into early ’24, for that northern hemisphere season, and then obviously, be ready for the subsequent southern hemisphere winter in 2024,” he said, according to the Sidney Morning Herald.

Since Moderna’s RSV vaccine uses the same messenger RNA technology as its successful Spikevax COVID-19 shots, “these data are encouraging, and represent the second demonstration of positive phase 3 trial results” from its mRNA infectious disease vaccine platform.

For Stéphane Bancel, Moderna’s Chief Executive Officer, “respiratory diseases are a major public health priority given they have a significant health impact and are a leading cause of hospitalization.”

“For these reasons, in addition to our mRNA-1345 RSV vaccine candidate, we are committed to developing a portfolio of respiratory mRNA vaccines to target the most significant viruses causing respiratory disease, including COVID-19, influenza, and human metapneumovirus,” he continued.


No FDA-approved RSV vaccine – yet

There currently is no FDA-approved vaccine for RSV.

However, at least four more products are in the pipeline by Johnson & Johnson, Pfizer, and GSK, also BIO member companies.

Pfizer’s RSVpreF vaccine candidate was 66.7% effective against less severe cases and 85.7% effective against more severe cases in the Phase 3 study. The GSK RSV OA vaccine candidate “showed 71.7% efficacy against cases that met its least severe case definition; 82.6% effective against cases that met its more severe case definition; and 94.1% effective against cases that met its most severe case definition.”

Barron’s noted it’s difficult to directly compare Moderna’s vaccine and Pfizer’s and GSK’s RSV vaccine candidates “as the vaccines were not tested against each other, and the definitions of severe and less-severe disease used in the studies do not match up.”

As we previously reported, Pfizer has two RSV vaccine candidates in the pipeline. The second one, RSVpreF maternal vaccine candidate, “met the success criterion for one of two primary endpoints” back in November by giving protection to newborns.

The RSVpreF investigational vaccine demonstrated 81.8% efficacy “for severe medically attended lower respiratory tract illness (severe MA-LRTI) through the first 90 days of life” and maintained a substantial efficacy of 69.4% “for infants over the six-month follow-up period,” Pfizer said at the time.

Per Barron’s, “FDA is set to decide in May on whether to approve Pfizer and GSK’s RSV vaccines for older adults and recommendations from the Centers for Disease Control and Prevention (CDC) – and a potential rollout -could come in June.”

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