Metagenomi's MGX-001 Gene Therapy Achieves Curative Factor VIII Levels in Hemophilia A Preclinical Study
Key Insights
Metagenomi (search)'s MGX-001 demonstrated curative factor VIII (search) activity levels of 49-81% in non-human primates, meeting the functional cure threshold for hemophilia A (search).
The genome editing therapy achieved dose-dependent FVIII (search) activity across both AAV and lipid nanoparticle components, with the proposed clinical dose reaching 49% average activity.
The company plans pre-IND regulatory meetings in Q4 2025 and expects to submit investigational new drug applications by the end of 2026.
Metagenomi (search) has announced breakthrough preclinical results for MGX-001, its investigational gene therapy for hemophilia A (search), demonstrating curative factor VIII (search) (FVIII (search)) activity levels in non-human primates that could transform treatment for patients with this inherited bleeding disorder. The dose range finding study achieved therapeutically relevant FVIII activity across multiple dosing regimens, positioning the therapy for clinical development with regulatory submissions expected by the end of 2026.
Preclinical Study Demonstrates Curative Potential
The comprehensive dose range finding study evaluated 24 non-human primates across six dose cohorts, administering varying doses of adeno-associated virus (AAV) containing a B-domain deleted human FVIII (search) gene (5.0e11 to 4.0e13 vg/kg) followed by lipid nanoparticles delivering the proprietary MG29-1 nuclease (search) mRNA and guide RNA (0.2, 0.6, or 2.0 mg/kg). Each animal received corticosteroids prior to both treatments.
The results demonstrated clear dose-dependent activity across both components of MGX-001. At a fixed LNP dose of 0.6 mg/kg with variable AAV doses of 1.6e12 to 4e13 vg/kg, the therapy achieved average per cohort FVIII (search) activity of 49-81%. When using a fixed AAV dose of 5e12 vg/kg with variable LNP doses, FVIII activity ranged from 17-72%.
"We are highly encouraged by the dose range finding results observed in this study where we have seen clear dose-dependent activity across both the AAV and LNP components of MGX-001, resulting in therapeutically relevant FVIII (search) activity in each animal treated in all but the lowest AAV dose," said Jian Irish, Ph.D., M.B.A., President and CEO of Metagenomi (search).
Clinical Dose Strategy Targets Functional Cure
A functional cure for hemophilia A (search) is generally defined as FVIII (search) levels of 50-150% of normal human levels. At the proposed clinical dose of AAV at 5e12 vg/kg and LNP at 0.6 mg/kg, MGX-001 achieved average FVIII activity of 49% within a range of 29.3-59.5%, approaching the functional cure threshold.
Importantly, no animal exceeded 150% of normal FVIII (search) activity, the maximum acceptable level, and the treatment was well tolerated across all dose groups. Only the highest LNP dose showed transient elevations in liver enzymes, while all other doses demonstrated favorable safety profiles.
The new data builds upon earlier studies demonstrating durable and stable FVIII (search) activity over approximately 19 months in non-human primates. MGX-001 has also shown no identifiable off-target editing in comprehensive safety assessments.
Addressing Significant Unmet Medical Need
Hemophilia A (search) affects an estimated 26,500 patients in the United States and more than 500,000 patients globally, according to the World Federation of Hemophilia. The X-linked inherited bleeding disorder results from mutations in the FVIII (search) gene leading to loss of functional FVIII protein, with intracranial bleeding representing the most serious complication due to potential for major morbidity and mortality.
"The MGX-001 approach represents a potential paradigm shift for the treatment of hemophilia A (search) patients who, even with currently approved therapies, are subject to rare but serious spontaneous bleeding events and must always ensure access to their treatment," said Glenn F. Pierce, M.D., Ph.D., an expert in hemophilia treatment and former hemophilia A patient.
Regulatory Timeline and Clinical Development
Metagenomi (search) expects to hold pre-IND regulatory meetings in Q4 2025, with investigational new drug (IND) and clinical trial application (CTA) submissions planned for Q4 2026. The company is leveraging the preclinical results in ongoing discussions with regulatory authorities.
Irish emphasized the therapy's potential as a curative approach: "In contrast to bispecific FVIII (search) mimetics or rebalancing therapies, MGX-001 enables endogenous production of FVIII for hemostatic regulation and restores the body's own ability to produce FVIII for a potentially lifelong cure."
Genome Editing Platform Technology
MGX-001 represents Metagenomi (search)'s lead wholly-owned development program utilizing the company's proprietary genome editing platform. The therapy combines site-specific genome integration with durable gene expression in a single treatment designed to provide lifelong protection from bleeding events and joint damage in both adults and children with hemophilia A (search).
The company's approach leverages metagenomics - the study of genetic materials from natural environments - to discover novel editing tools capable of correcting genetic mutations throughout the human genome. Metagenomi (search) is also pursuing other secreted protein deficiencies using the MGX-001 system and has partnered assets targeting cardiometabolic diseases.