Prime Medicine received FDA IND approval for PM-647, an investigational in vivo Prime Editor targeting adults with α-1 antitrypsin deficiency (AATD). The company plans a first-in-human Phase I/II trial evaluating a one-time intravenous infusion. The program includes AATD patients with lung and liver manifestations, setting up a core test of whether in vivo prime editing can achieve meaningful target engagement and safety. In practice, the approval signals continued regulatory openness to complex genome-editing modalities once sponsors complete required tox and CMC packages for first dosing.