Beacon Doses First Patient in its Phase 2/3 VISTA Clinical Trial for XLRP Gene Therapy
Research News
The company plans to apply for regulatory approval for the gene therapy with data from VISTA and its earlier clinical trials.
Beacon Therapeutics, an ophthalmic gene therapy company, has dosed the first patient in its Phase 2/3 VISTA clinical trial for AGTC-501, an emerging gene therapy for X-linked retinitis pigmentosa (XLRP) caused by mutations in the gene RPGR. VISTA will enroll 75 males between the ages of 12 and 50 at sites in the US with additional sites expected to open in other countries. The trial is evaluating two dosing levels of AGTC-501 as well as a control (placebo) group.
In February 2024, Beacon reported vision improvements for five of eight patients at 12 months after receiving the high dose of AGTC-501 in its Phase 2 SKYLINE clinical trial. Vision improvements were measured using microperimetry, a test that measures light sensitivity at several loci (points) in the central retina. The test also captures retinal images. The five of eight patients responding to the high dose of AGTC-501 had improvements in retinal sensitivity of at least 7 decibels in 5 or more loci. AGTC-501 was well-tolerated and no clinically significant safety events were associated with treatment.
Beacon plans to use data generated from VISTA, SKYLINE, and its Phase 1/2 HORIZON clinical trials to support application for regulatory approval for AGTC-501 in the US and EU.
AGTC-501 is delivered by a one-time subretinal injection. The XLRP gene therapy uses a human-engineered adeno-associated virus (AAV), which works like a vast container system, to deliver healthy copies of the RPGR gene to cells in the retina. According to Beacon, AGTC-501 expresses the full-length RPGR protein and is therefore expected to rescue function of both rod and cone photoreceptors.
The Foundation Fighting Blindness funded successful canine studies of XLRP gene therapy at the University of Pennsylvania School of Veterinary Medicine that helped make the XLRP gene therapy clinical trial possible.
XLRP affects approximately 20,000 people in the US and EU. As an X-linked condition, XLRP usually affects males. Though females are usually unaffected carriers of XLRP, they sometimes have vision loss, as well. The condition causes constriction of vision, reduced vision in dark settings, and central vision loss, especially in later stages. Most males with XLRP are legally blind by the age of 45.
