Complement Therapeutics Announces First Patient Dosed in Opti-GAIN Study for Geographic Atrophy

CTx001 gene therapy trial aims to treat leading cause of blindness in elderly

Mar. 25, 2026 at 10:50am

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Complement Therapeutics, a clinical-stage biotechnology company, has announced that the first patient has been dosed in Opti-GAIN, the company's first-in-human Phase I/II clinical trial of CTx001 in patients with Geographic Atrophy (GA) secondary to Age-related Macular Degeneration (AMD). Opti-GAIN is a multi-center study evaluating the safety, tolerability and preliminary efficacy of CTx001, an investigational AAV-based gene therapy designed to deliver mini-CR1 to modulate the complement system.

Why it matters

Geographic Atrophy is a leading cause of blindness in the elderly, affecting over 5 million people globally, and there is a significant unmet need for new treatment options. CTx001 aims to address this by leveraging clinically validated complement biology in GA while potentially offering a best-in-class profile due to broad ocular biodistribution, strong potency, and modulation of multiple complement pathways.

The details

The Opti-GAIN study is being conducted in two parts - an open-label, dose-escalation study in Part 1 followed by a dose-expansion phase in Part 2. The study is being advanced alongside Complement Therapeutics' ongoing Pre-GAIN natural history study, which is intended to support patient selection and the evaluation of novel structural and functional endpoints. Opti-GAIN is among the first studies to prospectively evaluate focal OCT-based microperimetry, an approach that has the potential to advance how the treatment effect is assessed in Geographic Atrophy.

  • The first patient was dosed in Opti-GAIN on March 25, 2026.

The players

Complement Therapeutics GmbH

A German-headquartered clinical-stage biotechnology company focused on the research and development of novel therapeutics for complement-mediated diseases.

Dr. Arshad M. Khanani

The trial's Chief Investigator and Director of Clinical Research at Sierra Eye Associates in Reno, Nevada.

Dr. Rafiq Hasan

Chief Executive Officer of Complement Therapeutics.

Dr. Muhammad Ali Memon

Chief Medical Officer of Complement Therapeutics.

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What they’re saying

“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.”

— Dr. Arshad M. Khanani, Chief Investigator, Opti-GAIN trial

“Dosing the first patient in Opti-GAIN is an important milestone for Complement Therapeutics and for the advancement of CTx001 in Geographic Atrophy.”

— Dr. Rafiq Hasan, Chief Executive Officer, Complement Therapeutics

“The precise surgical dosing strategy, adaptive immunomodulatory regimen and well-characterised patient population, from Complement's non-interventional i-GAIN and Pre-GAIN studies, provides a strong platform for CTx001 to demonstrate a therapeutic effect within Opti-GAIN.”

— Dr. Muhammad Ali Memon, Chief Medical Officer, Complement Therapeutics

What’s next

The Opti-GAIN study will continue to enroll patients and evaluate the safety, tolerability and efficacy of CTx001 over a 2-year period, followed by annual long-term safety follow-up for up to 5 years.

The takeaway

The initiation of the Opti-GAIN trial represents an important milestone in the development of a potential new treatment for Geographic Atrophy, a leading cause of blindness in the elderly. By leveraging a differentiated gene therapy approach and an integrated clinical development strategy, Complement Therapeutics aims to address this significant unmet medical need.