An Open Label, Multi-centrem Phase I/II Dose Escalation Trial of a Recombinant Adeno-associated Virus Vector (AAV2/5-hRKp.RPGR) for Gene Therapy of Adults and Children with X-linked Retinitis Pigmentosa Owing to Defects in Retinitis Pigmentosa GTPase Regulator (RPGR)

MGT-RPGR-022

Background

Retinitis pigmentosa (RP) is a group of inherited retinal diseases characterized by a progressive reduction in vision that first manifests as nyctalopia (night blindness) and usually occurs in childhood or early adulthood and progresses throughout life. Due to a number of X-linked forms, RP affects more males than females.

Currently, there is no approved therapeutic treatment for XLRP caused by mutations in RPGR (RPGR-XLRP). Among a number of new experimental strategies currently under investigation, gene therapy is considered the most promising.

This gene therapy study aims to determine whether a healthy version of the RPGR gene can correct this inherited error (defect) when delivered by injection into the retina during surgery.

Design

Approximately 90 adult subjects and up to 6 children and adolescents worldwide will participate in this study.

As part of this study, patients will be asked to give their consent to participate in 2 closely related studies. All participants must read the information about both studies and decide if they want to consent to participate. Initially, patients will participate in the first study (MGT-RPGR-021) for up to 18 months. Once patients have completed their participation in this study, they will proceed to the second study (MGT-RPGR-022), which has a follow-up period of 4 to 5 years.

The length of participation will depend on which treatment group the patient is assigned to in the study. It is necessary to have a group of non-treated participants to compare benefits and risks. Therefore, some participants will receive their treatment with a delay of 12 months. All participants will receive either the RPGR2e11 or RPGR4e11 dose of gene therapy tested in both eyes, either in the MGT-RPGR-021 study or 12 months later in the MGT-RPGR-022 study.