Complement Therapeutics announced completion of dosing in cohort 1 of the phase 1/2 Opti-GAIN trial evaluating CTx001, an investigational gene therapy for geographic atrophy (GA) secondary to age-related macular degeneration. The company also reported that an independent data monitoring committee reviewed safety findings from the first cohort, identified no significant safety concerns, and recommended proceeding to cohort 2 enrollment.

CTx001 is an adeno-associated virus 2–based gene therapy designed to deliver mini-CR1, a truncated form of complement receptor 1 intended to provide sustained local modulation of multiple complement pathways following a single subretinal injection.

The Opti-GAIN study is enrolling 75 participants and includes a differentiated endpoint strategy intended to assess structural and functional retinal changes at the individual patient level. Among the endpoints are ellipsoid zone integrity, intended to measure photoreceptor health, and focal optical coherence tomography–based microperimetry, designed to map retinal sensitivity in areas of GA. According to the company, these measures may provide earlier indications of treatment effect than conventional endpoints.

Complement Therapeutics said patients are already entering the run-in period for upcoming dosing cohorts, with additional updates expected in the second half of 2026. RP