MeiraGTx Holdings plc announced significant regulatory and clinical progress across its gene therapy pipeline during the second quarter of 2025, highlighted by FDA RMAT designation for its Parkinson's disease treatment and alignment on pivotal study requirements for radiation-induced xerostomia.
FDA Grants RMAT Designation for Parkinson's Disease Therapy
The FDA granted Regenerative Medicine Advanced Therapy (RMAT) designation to AAV-GAD for treating Parkinson's disease not adequately controlled with anti-Parkinsonian medications. This designation was awarded following presentation of positive data from three clinical studies demonstrating benefit when AAV-GAD is administered in a one-time stereotactic infusion to the subthalamic nucleus in the brain.
The supporting evidence included a Phase 1 dose escalation study (n=14), a double-blind sham-surgery controlled Phase 2 study (n=45), and a double-blind sham-surgery controlled Phase 1/2 clinical bridging study (n=14). In July 2025, the FDA completed a Good Clinical Practice inspection of the recent bridging study, resulting in a clean inspection with zero observations.
FDG-PET data from the positive Phase 2 double-blind, sham-surgery controlled clinical trials showed significant disease-modifying effects in pathological basal ganglia circuitry, including the substantia nigra—the site of dopamine-producing neurons affected in Parkinson's disease.
Pivotal Study Alignment for Radiation-Induced Xerostomia
MeiraGTx gained FDA alignment on its ongoing Phase 2 AQUAx2 randomized double-blind, placebo-controlled pivotal study in Grade 2/3 radiation-induced xerostomia (RIX) to support a potential Biologics License Application filing. The FDA aligned on the use of a single Patient Reported Outcome as primary endpoint, the 12-month timeframe for the primary outcome measure, pooling of placebo arms, and statistical analyses.
The Phase 2 AQUAx2 study is currently enrolling final high dose cohorts at multiple sites in the US, Canada and the UK, with target completion of enrollment in Q4 2025 and potential pivotal data readout in late 2026. AAV2-hAQP1 received RMAT designation from the FDA in December 2024 for treating Grade 2/3 RIX.
Breakthrough Results in Inherited Blindness
MeiraGTx is preparing regulatory submissions for AAV-AIPL1 to treat LCA4, with meaningful responses observed in all 11 LCA4 children treated to date. All children who were blind at birth are now able to see following treatment with AAV-AIPL1. The company plans to submit a Marketing Authorization Application in the UK and a BLA in the US in Q4 2025.
Data demonstrating the efficacy of rAAV8.hRKp.AIPL1 for treating LCA4 were published in The Lancet in February 2025. AAV-AIPL1 has orphan drug designation in the US and European Union, and the FDA's Offices of Orphan Products Development and Pediatric Therapeutics granted Rare Pediatric Disease Designation.
Strategic Partnership and Manufacturing Capabilities
MeiraGTx's strategic collaboration with Hologen AI received foreign direct investment clearances in the UK during Q2 2025. The company received $23 million of the $200 million in cash consideration, with the remainder expected in Q3 2025. The partnership will form joint venture Hologen Neuro AI Ltd, with additional committed funding from Hologen of up to $230 million to finance AAV-GAD program development to commercialization.
The company's manufacturing capabilities include five facilities globally, with two licensed for GMP viral vector production. The UK facility was successfully inspected in May 2024, confirming compliance with GMP requirements. The Shannon facility in Ireland received its first-of-its-kind license for gene therapy manufacturing in Ireland following a successful February 2025 inspection.
Financial Position and Pipeline Expansion
As of June 30, 2025, MeiraGTx had cash and cash equivalents of approximately $32.2 million. The company believes it has sufficient capital to fund operations into 2027 with current funds, third quarter proceeds, and remaining Hologen collaboration funding.
MeiraGTx continues advancing its riboswitch gene regulation technology platform, with compelling preclinical data in metabolic peptides and hormones showing greater efficacy on weight loss and improved glucose control. The company intends to initiate first-in-human studies using the riboswitch platform in 2025, with leptin likely being the first indication.
