MeiraGTx Announces Positive Clinical Data Demonstrating Treatment with AAV-RPGR Investigational Gene Therapy Improves Vision in X-Linked Retinitis Pigmentosa Patients

• Data being presented at the American Society of Retina Specialists (ASRS) 2020 Virtual Annual Meeting 

• Significant improvements demonstrated after treatment in Phase 1/2 clinical trial 

• Based on encouraging safety and efficacy profile, MeiraGTx and Janssen expect to progress AAV-RPGR into Phase 3 Lumeos clinical trial  

• MeiraGTx to host investor conference call on Friday, July 17 at 8:00 a.m. ET     

LONDON and NEW YORK, July 17, 2020 (GLOBE NEWSWIRE) -- MeiraGTx Holdings plc (Nasdaq: MGTX), a vertically integrated, clinical stage gene therapy company, today announced six-month data from the ongoing Phase 1/2 clinical trial (NCT03252847) of AAV-RPGR, an investigational gene therapy in development for the treatment of patients with X-linked retinitis pigmentosa (XLRP) with genetically confirmed variants in the RPGR gene. Significant improvement in vision was demonstrated in the dose escalation phase of the trial and AAV-RPGR was found to be generally well tolerated. These initial results from the trial are being presented as a late-breaker oral presentation at the American Society of Retina Specialists (ASRS) 2020 Virtual Annual Meeting.

MeiraGTx and Janssen Pharmaceuticals, Inc. (Janssen), one of the Janssen Pharmaceutical Companies of Johnson & Johnson, are jointly developing AAV-RPGR as part of a broader collaboration to develop and commercialize gene therapies for the treatment of inherited retinal diseases.

The ongoing Phase 1/2 MGT009 clinical trial consists of three phases: dose-escalation, dose-confirmation, and dose-expansion. In the dose-escalation phase (n=10), adults were administered low, intermediate, or high dose AAV-RPGR. Each patient was treated with subretinal delivery of AAV-RPGR in the eye that was more affected at baseline. The patient’s other eye served as an untreated control. The primary endpoint of the trial is safety, with secondary endpoints assessing changes in visual function at pre-specified timepoints post-treatment. Baseline values were determined in triplicate. 

At six months, significant improvement in retinal sensitivity was demonstrated in patients treated with low and intermediate dose AAV-RPGR. Improvement was evident at first post-treatment perimetry assessments at three months, with improvements generally sustained or increased at six months. Significant differences were observed in retinal sensitivity between treated and untreated eyes over time. Based on the robust safety and efficacy signals observed in the dose escalation portion of the study, the low and intermediate doses were selected for use in the ongoing randomized, controlled dose-expansion phase of the trial.