MeiraGTx reports three-year Phase 1 AQUAx data showing durable efficacy of AAV-hAQP1 gene therapy in radiation-induced xerostomia, with sustained saliva flow and symptom relief after a single dose.
Written By: Mennatullah Mansour, PharmD
Reviewed By: Pharmacally Editorial Team
MeiraGTx Holdings plc announced three-year data from its Phase 1 AQUAx clinical trial on April 16, 2026, showing sustained efficacy of its investigational gene therapy AAV-hAQP1 for patients with grade 2/3 late radiation-induced xerostomia.
The therapy, administered as a single dose via Stensen’s duct into the parotid glands, maintained improvements seen at 12 months through 36 months. Both patient-reported symptom relief and objective measures like unstimulated saliva flow stayed stable, indicating durable restoration of salivary gland function.
Durable Efficacy After One-Time Dosing
Alexandria Forbes, Ph.D., MeiraGTx CEO, stated the long-term data confirms AAV-hAQP1’s potential as a one-time treatment with lasting benefits. Group-level and individual patient responses remained consistent over three years.
Dr. Forbes emphasized the therapy’s durability in symptom relief and saliva production, response consistency across patients, and potential as a disease-modifying option rather than mere symptom management.
Addressing a Key Unmet Need
Radiation-induced xerostomia, a chronic condition from head and neck cancer radiation damaging salivary glands, lacks effective long-term treatments. AAV-hAQP1 targets this by restoring fluid secretion in damaged glands through localized delivery. The therapy’s simple in-office administration is building physician confidence due to its sustained impact.
Trial Design and Key Endpoints
The open-label, dose-escalation Phase 1 AQUAx study (NCT04043104) prioritizes safety, with secondary endpoints covering patient-reported symptom improvements and changes in salivary output. It enrols patients’ cancer-free for at least five years post-radiation (or at least two years if HPV-positive) with moderate-to-severe xerostomia. All receive single-dose treatment and five-year monitoring.
Clinical and Regulatory Progress
These three-year results, building on FDA Breakthrough Therapy Designation in March 2026 and prior RMAT status, position AAV-hAQP1 as a transformative option in a clear patient population. Ongoing Phase 2 AQUAx2 pivotal study enrolment supports its path forward. Further follow-up will verify long-term safety and efficacy beyond three years.
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About the Writer
Mennatullah Mansour is pursuing a PharmD and is based in Alexandria, Egypt. She is driven by a strong passion for continuous learning and professional development, with a focus on pharmaceutical care, patient health, and medication safety. Her interests include prescription processing, patient counseling, and interpreting clinical information. She brings a detail-oriented approach and a strong ability to translate medical knowledge into clear, accurate, and reliable content for healthcare audiences.