Valneva’s plans to establish its COVID-19 vaccine as a booster to Pfizer and BioNTech’s Comirnaty have taken a blow, with a clinical trial of the shot eliciting “only a marginally increased neutralizing antibody response.”
France’s Valneva has continued to try to carve out a space for VLA2001, a vaccine made of inactivated whole virus particles of SARS-CoV-2, despite seeing other companies establish dominant positions in the COVID-19 market. The bid for relevance led the company to run two trials of VLA2001 as a heterologous booster, one in recipients of Comirnaty and another in people primed with AstraZeneca’s Vaxzevria.
The Comirnaty study found VLA2001 failed to trigger a significant increase in neutralizing antibody levels, leading Valneva’s chief medical officer Juan Carlos Jaramillo, M.D., to say the “latest booster results are not aligned with the encouraging homologous and heterologous booster results seen previously” in a statement to disclose the setback.
Valneva’s data drop comes around one year after an independent trial, the U.K.’s COV-Boost, generated evidence that VLA2001 is a lackluster booster in people primed with Pfizer and BioNTech’s Comirnaty. In COV-Boost, VLA2001 was the only one of the seven tested vaccines to fail to meet the preestablished minimum clinically important difference in antibody levels when used to boost Comirnaty.
At the time, Valneva pinned the blame for the result on the design of the study, arguing that “the short interval between the second shot and booster shot could have adversely impacted the results for VLA2001, given that a longer interval is generally required for inactivated vaccines.”
Participants in Valneva’s own study received VLA2001 as a booster at least six months after their primary vaccination. Extending the lag between primary and booster vaccines failed to change the result, leaving Valneva looking to the use of VLA2001 in recipients of AstraZeneca’s Vaxzevria to salvage the program.
Valneva found antibody titers induced by VLA2001 were noninferior to Vaxzevria when used to boost recipients of the AstraZeneca vaccine in a trial that reported results last year. Based on the study, Valneva is seeking approval for VLA2001 as a heterologous booster in Vaxzevria-primed individuals. The company said approval “may support [it] in deploying its inventory in international markets.”