The FDA unveiled draft guidance aimed at expanding access to personalized gene therapies for rare diseases by allowing an initial approval for one mutation to be followed by later approvals for other mutations using laboratory data rather than a full new clinical trial each time. The proposal targets therapies designed to correct different mutations within the same disease-causing gene. Under the draft plan, a sponsor could submit an “individualized feature space” in the original application—defining the parameter range where additional mutation-specific therapies may qualify for clearance—reducing the clinical development burden for ultrarare patient subsets. The FDA also linked the guidance to broader work under its “Rare Disease Framework Initiative,” intended to set standards at the level of individual conditions rather than a one-size-fits-all pathway, and signaled continued engagement with industry developers of gene editing and base editing platforms. Markets quickly reacted to the concept of “plug and play” optionality, with analysts citing potential relevance for companies including Prime Medicine and Beam Therapeutics, and noted early public comments from those CEOs alongside company stock moves.