Shares of Novavax (NVAX) plunged 10.40% in intraday trading on Friday following news that the U.S. Food and Drug Administration (FDA) has requested the company to complete a new clinical trial for its delayed Covid-19 vaccine. This development has sent shockwaves through the market, causing investors to reassess their positions in the biotechnology firm.

According to a Wall Street Journal report, the FDA's demand for an additional clinical trial represents a significant setback for Novavax. The company has been working to bring its Covid-19 vaccine to market, but this latest hurdle could further delay the process and increase development costs. The news has raised concerns about Novavax's ability to compete in the increasingly crowded Covid-19 vaccine market, where several other pharmaceutical companies have already gained approvals and begun distributions.

The requirement for a new clinical trial suggests that the FDA may have concerns about the existing data or manufacturing processes related to Novavax's vaccine candidate. This development could potentially push back the timeline for the vaccine's approval and market entry, which is likely contributing to the negative sentiment among investors. As the pandemic continues to evolve and vaccination efforts progress worldwide, the market will be closely watching how Novavax navigates this challenge and what implications it may have for the company's future prospects in the competitive vaccine landscape.