FDA Clears Prime Medicine IND for PM647, an In Vivo Prime Editor for Alpha-1 Antitrypsin Deficiency
核心洞察
The FDA has cleared Prime Medicine's IND for PM647 (搜索), an investigational in vivo Prime Editor designed to correct the E342K (Pi*Z) mutation in SERPINA1 (搜索) in alpha-1 antitrypsin deficiency (搜索).
A global Phase 1/2 first-in-human trial will test ascending doses of a one-time intravenous infusion, initially enrolling adults with lung-only AATD before expanding to a liver disease cohort.
In fully humanized mouse models, PM647 (搜索) achieved high editing efficiency and restored corrected M-AAT protein into the healthy human range at clinically relevant doses with a single infusion.
Prime Medicine announced on Sept. 24, 2026 that the U.S. Food and Drug Administration has cleared its Investigational New Drug application for PM647 (搜索), an investigational in vivo Prime Editor for alpha-1 antitrypsin deficiency (搜索) (AATD). The clearance allows the Cambridge, Massachusetts-based company to proceed to clinical study initially in the United States, where approximately 100,000 people carry the PiZZ genotype that PM647 is designed to correct.
"FDA clearance of the PM647 (搜索) IND is an important milestone for Prime Medicine, marking continued momentum across our liver franchise," said Allan Reine, M.D., Chief Executive Officer of Prime Medicine. "PM647 has the potential to change how AATD is treated, offering a Prime Editing-based approach that moves beyond protein replacement and targets the root cause of disease."
Reine added that by correcting the underlying mutation and restoring production of fully functional AAT, PM647 (搜索) may simultaneously address both lung and liver manifestations of AATD and provide a differentiated, one-time treatment approach. He also noted that the program's advancement, coming months after regulatory clearances for PM577a (搜索), reflects how the company's modular platform and universal liver lipid nanoparticle (LNP) can support rapid progression of multiple programs.
Phase 1/2 Trial Design
The Phase 1/2 clinical trial will be a global, single-arm, open-label, first-in-human study designed to evaluate the safety, tolerability and preliminary clinical efficacy of ascending doses of a one-time intravenous infusion of PM647 (搜索) in adults with AATD.
The study will initially enroll adult participants with lung-only manifestations of AATD. Upon demonstration of tolerability in that population, the study will expand to include a separate cohort enrolling adults with significant liver disease, with or without concurrent lung manifestations of AATD. Initial clinical data are expected in 2027.
Mechanism and Preclinical Data
PM647 (搜索) is designed to correct the E342K (Pi*Z) mutation in the SERPINA1 (搜索) gene, described by the company as the most common cause of AATD. By correcting the mutation at its source, PM647 is intended to restore production of functional M-AAT and address both the liver and lung manifestations of the disease.
In fully humanized mouse models, PM647 (搜索) achieved high editing efficiency and restored corrected M-AAT protein into the healthy human range at clinically relevant doses with a single infusion. The candidate uses the same liver-directed LNP as PM577a (搜索), Prime Medicine's investigational program for Wilson disease (搜索).
Disease Burden and Unmet Need
Alpha-1 antitrypsin deficiency (搜索) is an inherited genetic disorder caused by variants in the SERPINA1 (搜索) gene. In people with severe disease, insufficient functional alpha-1 antitrypsin can lead to progressive lung damage, while accumulation of mutant protein in the liver can cause progressive liver disease. According to the company, patients have no approved curative treatment that addresses the underlying genetic cause of both manifestations of the disease. Approximately 200,000 people are estimated to carry the PiZZ genotype across the United States and Europe.
Platform Context
Prime Medicine describes its Prime Editing platform as a versatile, precise and efficient gene editing technology intended to make only the right edit at the right position within a gene while minimizing unwanted DNA modifications. The company states that Prime Editors have the potential to repair almost all types of genetic mutations and to work in many different tissues, organs and cell types.
The company's investigational portfolio is organized around three core areas: liver, lung, and immunology and oncology. Within each area, Prime Medicine says it is initially focused on high-value programs targeting diseases with well-understood biology and a clearly defined clinical development and regulatory path, with each program expected to provide a foundation for expansion into additional opportunities.