Ophthalmic gene therapy company Beacon Therapeutics has reported positive 12-month data from the Phase 2 SKYLINE trial of AGTC-501 in patients having X-linked retinitis pigmentosa (XLRP).

In males with XLRP, the 12-month data showcased a response rate of 63% in study eyes treated with a high dose of AGTC-501. Response rates in study eyes treated with a low dose of the gene therapy candidate were comparable to untreated fellow eyes in the high dose cohort.

Furthermore, patients in the high dose cohort displayed significant improvement in visual function, including mean retinal sensitivity.

AGTC-501 exhibited good tolerability, with no clinically significant safety concerns related to treatment, and any treatment-related adverse events were primarily nonserious and mild to moderate in severity.

Beacon Therapeutics chief medical officer Nadia Waheed said: “These data, which demonstrate a favourable safety profile and notable improvement in visual function, are another positive step in the development of AGTC-501 for XLRP, a blinding, orphan disease for which there is currently no approved treatment.

“We look forward to announcing the initiation of our Phase 2/3 VISTA trial in the first half of 2024.”

XLRP, an orphan disease primarily caused by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene, presents a significant medical challenge.

AGTC-501, which expresses the full-length RPGR protein, is anticipated to restore function in both rod and cone photoreceptors, positioning it as a promising treatment for patients with XLRP.

Beacon Therapeutics, which was established in June 2023, aims to develop innovative gene therapies for retinal diseases leading to vision loss.

The company’s inception involved merging the late-stage X-linked retinitis pigmentosa (XLRP) programme from AGTC and an additional preclinical initiative, to form a comprehensive ophthalmic development portfolio.

AGTC is a preclinical programme originating from the University of Oxford.

AGTC-501, which is the Beacon Therapeutics’s lead asset, was gained by AGTC through its acquisition of Syncona in late 2022.