The U.S. company Novavax announced yesterday that the FDA has removed the clinical hold placed on its COVID-19-influenza combination (CIC) vaccine and the stand-alone influenza vaccine candidates, which was enforced on October 16, 2024.
The clinical hold was announced after a participant who had received the CIC vaccine in a Phase 2a trial (completed in 2023) developed a serious adverse event, which was reported at the time as motor neuropathy.
"We are working closely with the FDA to provide the necessary information that will allow them to better understand this observation and resolve the clinical hold," said Robert Walker, Chief Medical Officer at Novavax, at the time.
"It is important to note that safety is our top priority, and while we do not believe causality has been established for this serious adverse event, we are committed to working expeditiously to fulfill requests for more information from the FDA. Our goal is to successfully resolve this matter and to start our Phase 3 trial as soon as possible."
After the company addressed all the clinical hold issues and provided the FDA with the necessary additional information, it was concluded that the patient had in fact suffered from amyotrophic lateral sclerosis. This condition, however, is not immune-mediated nor associated with the vaccination.
"We thank the FDA for their partnership and thorough review of the additional information provided as part of our response package," Walker said in a press statement. "The information provided to the FDA supported our assessment that the serious adverse event was not related to our vaccine. We plan to start our Phase 3 trial as soon as possible."
The company’s vaccines are based on the Matrix-M adjuvant technology, which comes from naturally occurring compounds called saponins, commonly found in the bark of the Chilean Soapbark tree. Novavax’s Matrix-M adjuvant particles are a key element of the vaccine technology platform. They are mixed with the vaccine nanoparticles to enhance the immune system’s response to the vaccines.
Novavax will now be working closely with clinical trial investigators and other stakeholders to resume the CIC vaccine and stand-alone influenza vaccine trials.
Other companies working on COVID-19-influenza combination vaccines are Pfizer and BioNTech together, as well as Moderna. All Phase 3 trials are still ongoing. While Moderna announced positive Phase 3 data in June 2024, BioNTech and Pfizer released an update on their Phase 3 trial in August 2024, revealing that their COVID-19-influenza combo vaccine candidate had not met one of the primary immunogenicity objectives, showing an inferior immune response against the influenza B strain.
