Bavarian’s Covid booster not a ‘commercial opportunity’ after data show its not as effective against new variants

Bavarian Nordic is abandoning its Covid-19 booster vaccine after Phase III results — even though it did hit the primary endpoint of the study — because it’s not as effective against newer variants of the virus.

The capsid virus-like particle (cVLP) based booster, called ABNCoV2, did lower the levels of neutralizing antibodies against the original SARS-CoV-2 variant. But even if the data found that it was non-inferior to the participants in the study who were vaccinated with Pfizer and BioNTech’s Comirnaty, it was for a variant that is “no longer the primary concern,” Bavarian said.

Bavarian looked at its booster’s effect on a newer variant circling the community and found that the neutralizing antibodies triggered by its vaccine were lower than those from Comirnaty. Data show 64% of people had detectable antibodies from Bavarian’s vaccine compared to 85% from Comirnaty.

There will be another six-month follow-up analysis as well as safety data collected for another six months, but Bavarian said its vaccine “cannot be readily adapted within the seasonal timeframe,” so the vaccine “no longer represents a commercial opportunity for Bavarian Nordic.”

The company added that it will discuss with the FDA how to use what it learned in the trial for future pandemics using cVLP-based vaccines.

Paul Chaplin

“We have generated robust data, so far demonstrating a favorable safety profile for the vaccine along with the ability to induce a strong and persistent immune response against earlier and more virulent strains, confirming the viability of the cVLP platform,” Bavarian president and CEO Paul Chaplin said in a statement.

Bavarian first licensed the virus-like particle vaccine ABNCoV2 from AdaptVac in 2020 and financed its clinical development beyond Phase I. cVLPs work like a standard virus-based vaccine, triggering the body’s immune response by binding to lymphocyte cells and making them think the body is infected. But it does not involve an actual foreign virus.

Other companies tried to develop virus-like particle vaccines for Covid without success. For example, Icosavax’s candidate flopped in 2022 because the receptor binding domain (RBD) of the antigen component of the vaccine became unstable during manufacturing and subsequent storage at 2-8 °C.

Icosavax decided to push ahead with its RSV vaccine using its virus-like particle platform. In 2022, the company said its Phase I/Ib trial in patients with RSV showed a “sustained” neutralizing antibody response, with plans to present more data the following year.

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