Munich, Germany – 25 March 2026: Complement Therapeutics GmbH (CTx), a clinical-stage biotechnology company developing next-generation therapies for complement-mediated diseases, today announced that the first patient has been dosed in Opti-GAIN, its first-in-human Phase I/II clinical trial evaluating CTx001 in patients with Geographic Atrophy (GA) secondary to Age-related Macular Degeneration (AMD).
Opti-GAIN is a multi-centre Phase I/II study designed to assess the safety, tolerability, and preliminary efficacy of CTx001, administered via a single subretinal injection. Part 1 of the study is an open-label, dose-escalation phase across three cohorts, followed by a dose-expansion phase in Part 2. The trial is being conducted by the company’s UK subsidiary.
“Geographic Atrophy remains an area of significant unmet need, with patients facing progressive and irreversible vision loss,” said Dr. Arshad M. Khanani, Chief Investigator of the study and Director of Clinical Research at Sierra Eye Associates, Reno, Nevada, USA. “I am pleased to be part of this first-in-human trial and to have administered CTx001 to the first patient. We look forward to further evaluating this promising one-time investigational gene therapy approach in GA secondary to AMD.”
CTx001 is an investigational AAV2-based gene therapy engineered to deliver a construct encoding mini-CR1, a truncated and secreted form of Complement Receptor 1. This approach is designed to modulate both the alternative and classical complement pathways. Subretinal administration enables local production of mini-CR1 within retinal cells, while its small size may facilitate penetration across Bruch’s membrane, supporting broad ocular biodistribution, including the choriocapillaris.
Building on clinically validated complement biology in GA, CTx001 aims to deliver a potentially best-in-class profile, combining broad ocular coverage, strong potency, multi-pathway modulation, and extended durability.
The Opti-GAIN trial is being conducted alongside Pre-GAIN, the company’s ongoing natural history study in GA, currently enrolling patients in both the United States and the United Kingdom. Together, these studies are expected to inform patient selection and enable the evaluation of novel structural and functional endpoints, including ellipsoid zone (EZ) integrity and focal Optical Coherence Tomography (OCT)-based microperimetry. Notably, Opti-GAIN is among the first clinical studies to prospectively evaluate focal OCT-based microperimetry, a method that could significantly advance treatment assessment in GA.
“Dosing the first patient in Opti-GAIN marks a key milestone for Complement Therapeutics and the clinical development of CTx001,” said Dr. Rafiq Hasan, Chief Executive Officer of Complement Therapeutics. “We believe our differentiated gene therapy approach, combined with an integrated clinical strategy, positions CTx001 strongly. Running Opti-GAIN alongside Pre-GAIN enables us to generate both interventional and natural history data to better guide patient selection, endpoint development, and future trials.”
Dr. Muhammad Ali Memon, Chief Medical Officer of Complement Therapeutics, added: “Our precise surgical delivery approach, adaptive immunomodulatory regimen, and well-characterised patient populations from i-GAIN and Pre-GAIN provide a strong foundation for demonstrating therapeutic impact with CTx001 in Opti-GAIN.”
Further details on the company’s clinical programmes are available on ClinicalTrials.gov, including Opti-GAIN (NCT07392255) and Pre-GAIN (NCT07144137).
