Top FDA officials and agency commentators outlined a new regulatory roadmap—often called the “plausible‑mechanism” pathway—intended to accelerate approvals for bespoke, patient‑specific therapies. The approach, detailed in high‑profile pieces and NEJM commentary, builds on the precedent set by the custom gene‑editing treatment for Baby KJ and would permit approval on mechanistic and laboratory data combined with other criteria in rare, urgent cases. Authors and agency figures emphasized the pathway’s potential to expand access for ultra‑rare diseases but acknowledged concerns: reviewers and industry experts warned the framework needs clearer guardrails on evidentiary standards and scaling, and implementation will require detailed guidance to ensure safety and reproducibility.