City Therapeutics, Inc. (NASDAQ:CTY) announced that the first participant has been dosed in its Phase 1 clinical trial evaluating CITY-RBP4, an investigational RNA interference (RNAi) treatment for Stargardt disease, an inherited retinal condition associated with progressive vision loss.
The biotechnology company expects to report initial clinical data from the study in mid-2027.
Phase 1 Trial Evaluates Safety and Drug Activity
The first-in-human, multicentre trial is a randomised, double-masked, placebo-controlled study involving healthy volunteers and patients with Stargardt disease.
The study will assess the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple subcutaneous doses of CITY-RBP4.
Researchers will measure reductions in retinol-binding protein 4 (RBP4) and circulating retinol, a form of vitamin A.
Participants with Stargardt disease may also enrol in a planned open-label extension study examining longer-term safety and preliminary efficacy, including retinal imaging and visual function assessments.
CITY-RBP4 Targets Vitamin A Transport to the Retina
CITY-RBP4 is designed to reduce production of RBP4 in the liver, limiting vitamin A transport to the eye.
Stargardt disease is caused by mutations in the ABCA4 gene, which result in the accumulation of toxic vitamin A byproducts in the retina and progressive vision loss.
The company said preclinical studies demonstrated sustained RBP4 suppression and reduced circulating retinol levels, supporting further clinical evaluation.
CITY-RBP4 is also being investigated for potential applications in geographic atrophy associated with age-related macular degeneration.
City Therapeutics Advances Clinical Pipeline
Chief Executive Officer Andy Orth commented:
“Advancing CITY-RBP4 into the clinic brings us an important step closer to addressing that unmet need, while also reflecting the significant progress of our pipeline.”
City Therapeutics now has two development programmes in clinical testing and expects a third to enter clinical evaluation through an investigator-initiated trial before the end of 2026.
Its broader pipeline includes CITY-FXI for thromboembolic diseases and CITY-TFR2 for anaemia associated with chronic diseases.
The company expects initial CITY-RBP4 Phase 1 results in mid-2027, with further development dependent on clinical findings.