Complement Therapeutics doses first patient in Phase 1/Phase 2 Opti-GAIN trial of CTx001 for geographic atrophy linked to AMD

Complement Therapeutics has dosed the first patient in its Phase 1/Phase 2 Opti-GAIN clinical trial evaluating CTx001, an investigational gene therapy for geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

The Opti-GAIN study is a first-in-human, multi-centre trial assessing the safety, tolerability and early efficacy of a single subretinal injection of CTx001. The study includes a dose-escalation phase followed by a dose-expansion stage, with patients monitored over two years and longer-term follow-up planned.

Geographic atrophy is an advanced form of dry AMD and a leading cause of blindness, affecting more than five million people globally. The condition is characterised by progressive degeneration of retinal cells, leading to irreversible vision loss. Despite recent advances, there remains a need for treatments that can slow or halt disease progression.

CTx001 is designed as an adeno-associated virus-based gene therapy that delivers a functional version of complement receptor 1 in a truncated form known as mini-CR1. The approach aims to regulate multiple pathways within the complement system, which has been implicated in the progression of GA.

Arshad Khanani, chief investigator of the trial, said: “Geographic Atrophy remains an area of significant unmet need, and there is a clear need to evaluate novel approaches for patients facing progressive vision loss.” He added: “I am pleased to be involved in this first-in-human study and to have administered CTx001 to the first patient in Opti-GAIN.”

The Opti-GAIN trial is being conducted alongside Pre-GAIN, an ongoing natural history study designed to better understand disease progression and support the development of clinical endpoints. The company said these parallel studies may help inform patient selection and improve how treatment effects are measured, including the use of imaging-based techniques such as optical coherence tomography.

Rafiq Hasan, chief executive officer of Complement Therapeutics, said: “Dosing the first patient in Opti-GAIN is an important milestone for Complement Therapeutics and for the advancement of CTx001 in Geographic Atrophy.”

Muhammad Ali Memon, chief medical officer of Complement Therapeutics, added that the study design, including prior observational data from related studies, is intended to support evaluation of treatment response in a defined patient population.

While the trial represents an early step in clinical development, it reflects continued interest in gene therapy approaches targeting complement biology in ophthalmology. Several therapies in this class have shown potential to slow disease progression, but questions remain around durability, delivery and long-term safety.

Results from Opti-GAIN will be needed to determine whether CTx001 can demonstrate a meaningful clinical effect in patients with GA.