Gene Therapy PST-611 Shows Early Promise Against Dry AMD in Phase 1 Trial

Dry age-related macular degeneration is a leading driver of irreversible vision loss in aging populations, and currently has very limited treatment options. Geographic atrophy, its most advanced form, involves the progressive death of retinal cells and photoreceptors — often linked to iron dysregulation in the eye. PST-611 is a gene therapy designed to address this root cause by delivering a transferrin-encoding gene to restore iron balance and protect retinal tissue.

In the first-in-human Phase 1 trial PST-611-CT1, six patients across two dose levels received a single injection and were followed for 16 weeks at sites in Paris and Grenoble. The trial met its primary and secondary objectives, demonstrating excellent safety and tolerability. Adverse events were mostly mild and ocular, with no intraocular inflammation and no serious adverse events — a critical threshold for advancing to later-stage trials.

Although the trial was not designed to test efficacy, early signals were encouraging. Patients self-reported vision improvements, and anatomical data showed inflections — apparent slowdowns — in geographic atrophy lesion growth. Notably, at least one of these signals persisted beyond the 16-week follow-up window, suggesting a potentially durable biological effect.

PulseSight has submitted an application to French regulators for a Phase 2a trial involving three repeat high-dose administrations over 52 weeks in up to 20 patients. Results are expected in 2028. Preclinical data cited by the company showed photoreceptor and retinal pigment epithelium protection alongside preserved visual function.

For those tracking longevity and healthspan, preserving vision into later decades is a meaningful quality-of-life and functional independence issue. While these results are preliminary and come from a very small, non-randomized cohort, PST-611 represents a mechanistically novel approach to a condition affecting millions of older adults globally.