FDA leaders outlined a new regulatory framework to accelerate approvals for individualized and ultra‑rare therapies by allowing plausible‑mechanism evidence in lieu of traditional randomized trials in select cases. The perspective—aimed at scaling the ‘Baby KJ’ bespoke gene‑editing precedent—details criteria developers should meet, including mechanistic validation, safety monitoring plans, and manufacturing controls. Agency officials framed the pathway as a way to enable patient‑specific interventions while maintaining standards for evidence and oversight.