PulseSight reports early efficacy signals for PST-611 in geographic atrophy, with post hoc OCT analysis showing 35% to 52% lower biomarker growth rates.
Written By: Charvi Kalal, PharmD
Reviewed By: Pharmacally Editorial Team
PulseSight Therapeutics SAS announced on October 7, 2026, new data from the Phase I PST-611-CT1 trial evaluating PST-611 in patients with geographic atrophy (GA), an advanced form of dry age-related macular degeneration (AMD). The findings were presented by Chief Medical Officer George Weissgerber, MD, on October 2 at the 26th EURETINA Congress in Vienna.
Geographic Atrophy and PST-611
AMD is a major cause of vision loss in older adults, and PulseSight estimates that it affects approximately 200 million people worldwide. Dry AMD can progress to GA, which involves progressive and irreversible loss of retinal pigment epithelium (RPE) and photoreceptor cells.
PST-611 is an investigational gene therapy designed to encode human transferrin, a protein involved in iron homeostasis. PulseSight’s approach is based on evidence that dysregulated iron and excess free iron may contribute to oxidative stress, inflammation and ferroptosis in retinal disease.
The therapy uses a non-viral delivery system in which DNA plasmids encoding transferrin are delivered into the ciliary muscle using electro-transfection. The muscle cells are intended to produce transferrin locally and release it toward the retina. Preclinical studies reported by PulseSight showed protection of RPE and photoreceptors and preservation of visual function in animal models.
Phase I Study and Earlier Findings
PST-611-CT1 was a first-in-human Phase I study primarily designed to evaluate the safety and tolerability of a single administration. Six patients with advanced dry AMD/GA were treated in two successive dose cohorts and followed for approximately four months.
Earlier results presented at ARVO in May 2026 showed favorable safety and tolerability at both dose levels. Most ocular adverse events were mild, with two moderate events reported. No intraocular inflammation or treatment-emergent serious adverse events were reported, and best-corrected visual acuity remained stable during follow-up.
The study was not designed to establish efficacy.
Post Hoc Analysis Shows Early Structural Signals
Following observations of slower GA lesion growth on optical coherence tomography (OCT) and spontaneous reports of improved vision from some participants, PulseSight conducted a quantitative post hoc analysis using the RetinAI Discovery platform and artificial intelligence models.
The analysis evaluated four OCT biomarkers associated with retinal cell loss before and after treatment. PulseSight reported early efficacy signals in five of the six treated patients.
Across the treated population, the growth rate of all four biomarkers decreased by a mean of 35% to 52% during the four months after treatment compared with the pretreatment period. Specifically, the growth rate of RPE depletion decreased by 40%, the rate of ellipsoid zone (EZ) depletion decreased by 35%, and EZ thickness loss decreased by 52%.
The structural findings were accompanied by spontaneous reports from some participants of improved vision during daily activities. However, these reports were not based on a prespecified visual efficacy endpoint.
PulseSight said the consistency of the structural response and its early onset support further clinical evaluation of PST-611.
Phase IIa Trial Planned
PulseSight plans to evaluate PST-611 in the Phase IIa PST-611-CT2a study. The October announcement describes a trial of up to 24 patients, with up to three administrations over 12 months. The company expects the study to begin in the second half of 2026, with results anticipated in 2028.
Earlier company communications had described the Phase IIa study as involving up to 20 patients with a 52-week design. The updated enrollment and study details should therefore be confirmed against the registered clinical trial protocol.
Findings Require Further Confirmation
The new findings should be interpreted cautiously because they come from a six-patient, uncontrolled Phase I study and the efficacy analysis was conducted post hoc. Each patient’s post-treatment biomarker growth rate was compared with their own pretreatment rate rather than with a concurrent control group.
Consequently, the analysis cannot determine how much of the observed reduction was attributable to PST-611 rather than natural variability in GA progression. The announcement also does not provide individual patient-level results, statistical testing or confidence intervals.
The OCT findings therefore represent preliminary structural signals rather than established clinical efficacy. The patient-reported visual improvements should similarly be considered exploratory.
PST-611 remains an investigational therapy and is not approved for any indication.
Reference
PulseSight presents PST-611 Phase I new early clinical efficacy data at EURETINA, offering a potential breakthrough approach to treat Dry AMD/Geographic Atrophy, PulseSight Therapeutics, 07 October 2026
About the Writer
Charvi Kalal (LinkedIn) is a Pharm.D intern and aspiring medical writer with hands-on experience in medical writing, clinical research, pharmacovigilance, and clinical pharmacy. She has experience in medical content writing through CliMed, along with exposure to ADR monitoring, prescription analysis, patient counselling, literature review, and research documentation. Her research focuses on ADR monitoring and reporting in breast cancer patients receiving targeted therapy. With certifications in GCP, biomedical research, scientific writing, and clinical research, she is passionate about transforming scientific evidence into accurate, engaging, and accessible healthcare content.