FDA takes up the first in vivo CRISPR therapy for review

The FDA accepted Intellia Therapeutics’ Biologics License Application for lonvoguran ziclumeran — lonvo-z — on 8 September 2026, granting priority review and setting a target decision date of 10 March 2027. If it is approved, it will be the first CRISPR therapy that edits genes inside the patient’s body rather than in cells removed, edited and returned.

The distinction is the whole point. Casgevy, approved in 2023, works by taking a patient’s stem cells out, editing them in a facility and infusing them back after chemotherapy clears the marrow. Lonvo-z is an infusion. It travels to the liver and disables the KLKB1 gene, cutting production of the protein that drives swelling attacks in hereditary angioedema.

The Phase 3 HAELO trial enrolled 80 patients worldwide. Mean monthly attacks fell 87% against placebo, and 62% of patients in the treatment arm went the full six-month evaluation period with no attacks and no HAE medication at all, against 11% on placebo. It is given once.

Hereditary angioedema is rare, and this is a narrow indication. What the review tests is broader: whether a regulator will license permanent edits made in a living adult.