US regulatory policy is shifting on two fronts. FDA officials and agency authors proposed a 'plausible mechanism pathway' to expedite approval of bespoke therapies for very rare diseases that cannot be evaluated in randomized trials; the paper cites the n‑of‑1 CRISPR treatment given to infant 'KJ' as precedent. Separately, the FDA proposed reclassifying certain companion diagnostic nucleic acid tests from Class III to Class II devices to allow 510(k) review. Together these moves lower regulatory barriers for some precision medicines and diagnostics, but experts warn they must be paired with robust post‑market controls to protect patients.