The U.S. Food and Drug Administration (FDA) has placed a clinical hold on Novavax's trials for its COVID-19-Influenza Combination (CIC) and standalone influenza vaccines. This decision comes after a participant in a Phase 2 trial reported a serious adverse event (SAE) of motor neuropathy. The participant, who received the vaccine in January 2023, reported the SAE in September 2024, after the trial had concluded in July 2023.

Novavax, a biotechnology company known for its protein-based COVID-19 vaccine, is now working closely with the FDA to resolve the clinical hold. The company has emphasized that safety is their top priority and that causality between the vaccine and the adverse event has not been established. Despite this setback, Novavax's existing COVID-19 vaccine remains unaffected by the hold.

The news has had a significant impact on Novavax's market position, with shares plunging over 24% in premarket trading. The company had previously signed a $1.2 billion licensing deal with Sanofi to co-sell its vaccines, which is now under pressure due to the trial hold. Investors are concerned about potential delays in the Phase 3 trial and the impact on Novavax's competitive position in the vaccine market.

Novavax's Chief Medical Officer, Robert Walker, MD, stated that the company is committed to providing the necessary information to the FDA to resolve the issue and proceed with the trials. The company is also addressing investor concerns about the potential financial implications, including increased R&D expenses and the impact on future funding opportunities.

As Novavax navigates this challenging period, the focus remains on ensuring the safety and efficacy of its vaccine candidates while maintaining transparency with regulatory authorities and investors.