Results from Phase I/II MGT009 study into investigational gene therapy botaretigene sparoparvovec suggest sustained vision improvement in patients with X-linked retinitis pigmentosa (XLRP).
The study found treatment with botaretigene sparoparvovec had an acceptable safety profile and demonstrated encouraging improvements in retinal sensitivity, visual function and functional vision.
The late-breaking results were revealed at the American Academy of Ophthalmology 2022 Annual Meeting. Data from a separate Phase I study were also presented, which show that another investigational gene therapy JNJ-1887 was safe in adults with geographic atrophy (GA).
XLRP is a rare condition which causes progressive vision loss, but currently has no approved treatments.
Potential to preserve vision
Botaretigene sparoparvovec is being investigated in collaboration with MeiraGTx Holdings to treat patients with XLRP caused by disease-causing variants in the eye-specific form of the RPGR (RPGR ORF15) gene. Through a one-time administration, the drug is designed to deliver functional copies of the RPGR gene to counteract the loss of retinal cells.
“Individuals living with XLRP often begin to experience symptoms in childhood, and as retinal degeneration progresses toward blindness, they can start to feel a sense of hopelessness as there are no treatments to turn to,” said Michel Michaelides, Consultant Ophthalmologist, Moorfields Eye Hospital, Professor of Ophthalmology, University College London and lead investigator.
“These results from the MGT009 study are promising, as they represent the potential for botaretigene sparoparvovec to preserve vision and ultimately restore hope for these patients.”
Botaretigene sparoparvovec has been granted Fast Track and Orphan Drug designations by the US Food and Drug Administration (FDA) and PRIority MEdicines (PRIME), Advanced Therapy Medicinal Product (ATMP) and Orphan designations by the European Medicines Agency (EMA).
Phase I study in GA
Data were also shared from a Phase I safety and tolerability study of a single intravitreal injection of JNJ-1887 in patients with advanced non-exudative (dry) age-related macular degeneration (AMD) with GA.
All three doses of JNJ-1887 met the primary endpoint of safety over the two-year follow-up period, as well as a continual decline in lesion growth over six-month increments.