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  • Retinitis Pigmentosa Responds to Gene Therapy


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    In a phase 1/2 study, the gene therapy AAV5-RPGR (MeiraGTx/Janssen) showed positive results in patients with RPGR-associated X-linked retinitis pigmentosa (XLRP), reported Michel Michaelidis, MD, on Saturday at Retina Subspecialty Day. The treatment, delivered via a recombinant adeno-associated virus vector, is also known as botaretigene sparoparvovec.

    Study design. For this open-label proof-of-concept study, investigators at five U.K. and U.S. sites enrolled 10 adults in a dose-escalation phase, three children in a dose-confirmation phase, and 32 adults and children in an expansion phase. (The latter included a randomized control group of 13 participants.)

    All participants were males 5 years of age or older. Other key inclusion criteria included disease caused by variants in RPGR and evidence on spectral-domain OCT of relative preservation of retinal structure in the macula.

    Results. Dr. Michaelidis outlined the following outcomes:

    • The gene therapy demonstrated an adverse event profile that was “anticipated and manageable,” Dr. Michaelidis said. Most events were transient and related to surgical delivery of the therapy, and they resolved without intervention.
    • At six months, eyes treated with AAV5-RPGR had improved in retinal sensitivity and functional vision in comparison with randomized controls.

    With regard to functional vision, Dr. Michaelidis presented a video illustrating one patient’s ability to navigate a maze in low-light conditions of 1 lux. At baseline, it took 61.7 seconds for the participant to navigate the maze, with two errors. In contrast, he was able to get through the maze in 16.4 seconds, with no errors, at the nine-month mark.

    Looking ahead. A phase 3 study of AAV5-RPGR is now underway, Dr. Michaelidis noted. The study’s primary outcome is retinal sensitivity as measured by perimetry.1 —Jean Shaw

    1 https://clinicaltrials.gov/ct2/show/NCT04671433.

    Financial disclosures: Dr. Michaelidis: 2C Tech: C; Acucela: C, PS; Belite Bio: C, PS; Claris Bio: C; Janssen: C; MeiraGTx: C, PS; Mogrify: C; ProQR: PS; Stargazer Pharmaceuticals: C.

    Disclosure key: C = Consultant/Advisor; E = Employee; EE = Employee, executive role; EO = Owner of company; I = Independent contractor; L = Lecture fees/Speakers bureau; P = Patents/Royalty; PS = Equity/Stock holder, private corporation; S = Grant support; SO = Stock options, public or private corporation; US = Equity/Stock holder, public corporation For definitions of each category, see aao.org/eyenet/disclosures.

    Read more news about Subspecialty Day and AAO 2022.