MeiraGTx Announces Positive Clinical Data Demonstrating Treatment with AAV-RPGR Investigational Gene Therapy Improves Vision in X-Linked Retinitis Pigmentosa Patients
July 17, 2020
• Data being presented at the
• Significant improvements demonstrated after treatment in Phase 1/2 clinical trial
• Based on encouraging safety and efficacy profile,
• MeiraGTx to host investor conference call on
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.
“XLRP is characterized by early-onset visual field loss, with most patients progressing to blindness and associated loss of independence by young adulthood,” said
Based on the encouraging safety and efficacy data demonstrated in the MGT009 trial to date,
“We are pleased to share these encouraging initial results from our XLRP gene therapy trial and look forward to advancing this program into a Phase 3 trial,” said
Data obtained to date suggest AAV-RPGR is generally well-tolerated. Most adverse events (AEs) were related to the surgical delivery procedure, were transient and resolved without intervention. There were no dose-limiting events. Inflammatory responses to therapy were observed in two out of three patients in the high dose cohort, which may have been associated with decreased activity of AAV-RPGR in these patients. Inflammation was effectively managed with an extended steroid protocol.
Six-month data from the dose escalation portion of the study (n=10) demonstrated meaningful improvement from baseline in retinal sensitivity in the low (n=3) and intermediate (n=4) dose cohorts. Importantly, these improvements were evident when assessed with two perimetry approaches (static perimetry and microperimetry) and three analysis metrics (mean retinal sensitivity, central 30° hill-of-vision volumetric measure (V30), and pointwise comparison).
- Significant differences in mean retinal sensitivity were observed between treated eyes and untreated eyes in the intermediate dose cohort: 1.02 dB (90% CI: 0.75, 1.31)
- Significant differences were observed in central visual field progression rate (V30) between treated eyes and untreated eyes in both the low2, 1.10 dB-sr/year (90% CI: 0.10, 2.10) and intermediate, 1.26 dB-sr/year (90% CI: 0.65, 1.86), dose cohorts.
- Efficacy signals were observed at first post-treatment assessments at three months, with improvements generally sustained or increased at six months.
Perimetry is a sensitive standard-of-care measure of retinal function that reproducibly determines retinal sensitivity both cross-sectionally and longitudinally, thereby accurately defining disease progression over time.
ASRS Presentation Information:
Title: AAV-RPGR Gene Therapy for RPGR-Associated X-Linked Retinitis Pigmentosa: 6-month Results From a Phase 1/2 Clinical Trial
Date: Oral presentation available to ASRS meeting attendees on the virtual meeting site as of
Session: Hereditary Retinal Diseases Symposium
Conference Call Information:
AAV-RPGR is an investigational gene therapy for the treatment of patients with XLRP caused by mutations in the eye specific form of the RPGR gene (RPGR ORF15). AAV-RPGR is designed to deliver functional copies of the RPGR gene to the subretinal space in order to improve and preserve visual function.
About the Phase 1/2 MGT009 Clinical Trial
MGT009 is a multi-center, open-label Phase 1/2 trial (NCT03252847) of AAV-RPGR gene therapy for the treatment of patients with XLRP associated with disease-causing variants in the RPGR gene. MGT009 consists of three phases: dose-escalation, dose-confirmation, and dose-expansion. 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. In dose-escalation (n=10), adults were administered low, intermediate, or high dose AAV-RPGR. The primary endpoint was safety. Visual function was assessed at baseline, three, six, nine and 12 months with Octopus 900 full-field static perimetry and mesopic fundus-guided microperimetry (MP); mean retinal sensitivity, visual field modeling and analysis (VFMA; Hill-of-vision volumetric measure), and pointwise comparisons were examined.
About X-Linked Retinitis Pigmentosa (XLRP)
XLRP is the most severe form of retinitis pigmentosa (RP), a group of inherited retinal diseases characterized by progressive retinal degeneration and vision loss. In XLRP, both rods and cones function poorly, leading to degeneration of the retina and total blindness. The most frequent cause of XLRP is disease-causing variants in the RPGR gene, accounting for more than 70% of cases of XLRP, and up to 20% of all cases of RP. There are currently no approved treatments for XLRP.
For more information, please visit www.meiragtx.com.
Forward Looking Statement
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including, without limitation, statements regarding the development and efficacy of AAV-RPGR, plans to advance AAV-RPGR into Phase 3 clinical trial and anticipated milestones regarding our clinical data and reporting of such data and the timing of results of data, including in light of the COVID-19 pandemic, as well as statements that include the words “expect,” “intend,” “plan,” “believe,” “project,” “forecast,” “estimate,” “may,” “should,” “anticipate” and similar statements of a future or forward-looking nature. These forward-looking statements are based on management’s current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, our incurrence of significant losses; any inability to achieve or maintain profitability, acquire additional capital, identify additional and develop existing product candidates, successfully execute strategic priorities, bring product candidates to market, expansion of our manufacturing facilities and processes, successfully enroll patients in and complete clinical trials, accurately predict growth assumptions, recognize benefits of any orphan drug designations, retain key personnel or attract qualified employees, or incur expected levels of operating expenses; the impact of the COVID-19 pandemic on the status, enrollment, timing and results of our clinical trials and on our business, results of operations and financial condition; failure of early data to predict eventual outcomes; failure to obtain FDA or other regulatory approval for product candidates within expected time frames or at all; the novel nature and impact of negative public opinion of gene therapy; failure to comply with ongoing regulatory obligations; contamination or shortage of raw materials or other manufacturing issues; changes in healthcare laws; risks associated with our international operations; significant competition in the pharmaceutical and biotechnology industries; dependence on third parties; risks related to intellectual property; changes in tax policy or treatment; our ability to utilize our loss and tax credit carryforwards; litigation risks; and the other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the quarter ended
2 Excludes one subject with panuveitis in the low dose cohort