The FDA unveiled draft guidance aimed at making rare-disease gene therapies more scalable, proposing a “plug and play” framework for personalized treatments that target different mutations within the same disease-causing gene. Under the approach, a sponsor could pursue initial approval for one mutation using a more traditional clinical program, then expand to additional mutation-specific variants later using laboratory data rather than repeating full clinical trials. The proposal introduces an “individualized feature space” concept to define what additional mutation-specific approvals could cover in the original application package. The FDA positioned the guidance as part of broader work to support rare disease development economics and reduce barriers for conditions where conventional clinical trials are impractical. Beam Therapeutics CEO John Evans said the approach is “completely supported by the science of base editing,” while Prime Medicine is also seen as a potential beneficiary of the optionality the FDA is trying to create.