The FDA unveiled draft guidance aimed at making personalized gene therapies for rare diseases easier to develop and approve, focusing on treatments that target different mutations within the same disease gene. Under the proposal, a manufacturer could obtain approval for one personalized therapy using a more traditional development path, then seek later approvals for additional mutations using laboratory data rather than full new clinical studies. The agency described a framework for an “individualized feature space” laid out in the original application, which would define how later mutation-specific therapies fit within the established scientific and regulatory boundaries. FDA said the approach is meant to reduce the need for clinical trials that may be impractical when the target mutation affects too few patients. The initiative connects to the FDA’s broader Rare Disease Framework Initiative, intended to set standards by individual conditions rather than a one-size-fits-all approach. The concept was quickly seen as relevant to gene-editing and base-editing programs, with market reaction reported for companies discussing personalization-by-design.