AAV5-RPGR Gene Therapy for RPGR-Associated X-Linked Retinitis Pigmentosa- Janssen (Johnson & Johnson) & MEIRAGTx

Highlights of AAV5-RPGR Gene Therapy Program

- AAV5-RPGR is an investigational gene therapy product for RPGR-Associated X-Linked Retinitis Pigmentosa
- Developed by Janssen (Johnson & Johnson) & MEIRAGTx
- 12-months ongoing Phase 1 & 2 clinical trial data  were presented at AAO 2020 conference
- Data showed that low and intermediate doses were well-tolerated
-  Demonstrated statistically significant sustained or increased vision improvement across multiple metrics and modalities

RPGR-Associated X-Linked Retinitis Pigmentosa

In patients with XLRP, the photoreceptors that are responsible for converting light into signals that are sent to the brain, function poorly, leading to a degeneration of the retina and legal blindness in adulthood. 

Gene Therapy Platform
AAV5-RPGR is an investigational gene therapy product. It is delivered via subretinal injection targeting the central retina in the eye that was more affected at baseline.

Regulatory Status of AAV5-RPGR Gene Therapy Program

U.S. Food and Drug Administration (FDA)
Received Fast Track designation from the FDA, Orphan designations from the FDA.

The European Medicines Agency (EMA)
EMA granted PRIME (PRIority MEdicines) and Advanced Therapy Medicinal Product (ATMP) designations to AAV-RPGR. Orphan designations from the EMA.

Clinical Trial Update of AAV5-RPGR Gene Therapy Program

GT009 (NCT03252847) is an open-label, multi-center, dose-escalation trial, which enrolled patients aged five years and older with XLRP caused by mutations in RPGR at multiple sites in the United States and the United Kingdom. 

The primary endpoint was safety and tolerability; secondary endpoints assessed retinal sensitivity, visual function, functional vision, and quality of life measurements. The ongoing Phase 1/2 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. AAV-RPGR is delivered via subretinal injection targeting the central retina in the eye that was more affected at baseline. The patient's other eye served as an untreated control.

Safety
Safety data to date has demonstrated ocular and systemic safety profiles that are anticipated and manageable. The most common adverse events were related to the surgical procedure, transient, and resolved without intervention. In the high dose cohort (n=3), inflammation was evident in two of three adults, and measures of visual function were not improved.

Efficacy
Statistically significant differences in mean retinal sensitivity were observed between treated and untreated eyes in the intermediate dose cohort: 1.05 decibel (dB); (90% CI: 0.81, 1.29).
Statistically significant differences were observed in central visual field progression rate (V30) between treated and untreated eyes in the low: 1.10 dB-sr (steradian)/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 sustained or increased at 12 months.



Reference
https://www.janssen.com/
https://meiragtx.com/
https://www.prnewswire.com/news-releases/late-breaking-12-month-data-of-investigational-rpgr-gene-therapy-shows-statistically-significant-and-continued-vision-improvement-in-patients-with-x-linked-retinitis-pigmentosa-301173016.html
https://meiragtx.com/wp-content/uploads/2020/11/AAO_2020_RPGR_12_month.pdf