The news triggered an immediate 7% sell-off, dragging the stock price down to $39.00 in extended trading. This reversal interrupts a period of growth for the biopharmaceutical firm, whose shares had climbed 32% over the previous 12 months. The decline reflects investor anxiety over the timeline for Moderna’s respiratory pipeline as the company seeks to diversify its revenue beyond COVID-19 products.

The FDA’s Data Requirements

According to the company, the FDA issued a refusal-to-file letter earlier this month, a procedural move that halts the approval process before a formal review can begin. The agency’s primary objection centered on the design of Moderna’s clinical trials. Regulators stated the study was insufficient because it did not compare the experimental shot against the most effective vaccines currently available on the market.

Despite the rejection, Moderna emphasized that the FDA did not raise any concerns regarding the safety or efficacy of the vaccine candidate. The company now plans to request a formal meeting with the agency to address the data gaps and determine a path forward for its clinical program.