FDA refuses to review Moderna’s mRNA flu vaccine application

The U.S. Food and Drug Administration (FDA) refused to consider Moderna’s application for a new flu vaccine using mRNA technology, the company announced Tuesday, a decision that could delay the introduction of a shot designed to offer stronger protection for older adults.

Moderna said it received what’s known as a "refusal-to-file" (RTF) letter from the FDA's Center for Biologics Evaluation and Research (CBER), citing the lack of an "adequate and well-controlled" study with a comparator...