Key Takeaways

  • At Week 20, 41.4% of CSB-001-treated eyes gained at least 15 BCVA letters, compared with none of the untreated eyes

  • Visual acuity improvements persisted for up to 16 weeks after treatment, and CSB-001 was generally well tolerated

  • Claris plans to begin 2 pivotal trials involving approximately 400 patients in the first half of 2027

Claris Biotherapeutics announced positive results from an open-label proof-of-concept study evaluating CSB-001 (oremepermin alfa ophthalmic solution) in patients with limbal stem cell deficiency (LSCD). The findings were presented at the American Academy of Ophthalmology (AAO) 2026 Annual Meeting in New Orleans.

The study (NCT06452316) evaluated 49 eyes from 39 patients with central corneal conjunctivalization and baseline best-corrected visual acuity (BCVA) of 65 letters or fewer. Of these, 29 eyes from 23 patients received topical CSB-001 four times daily during two 8-week treatment periods separated by a 1-month dosing holiday. The remaining 20 eyes from 16 patients served as untreated controls.

At Week 20, 41.4% of CSB-001-treated eyes achieved gains of at least 15 BCVA letters, while 55.2% gained at least 10 letters. Overall, 76% of treated eyes demonstrated some visual acuity improvement.

In comparison, no untreated eyes achieved gains of 15 letters or more, and 5% gained at least 10 letters.

Visual improvements persisted following treatment discontinuation. Among treated eyes achieving gains of at least 15 or 10 letters at Week 20, 50% and 81%, respectively, maintained those improvements for an additional 16 weeks.

Investigators also reported a strong correlation between anatomical improvements and visual acuity gains. CSB-001 was generally safe and well tolerated.

CSB-001 contains recombinant human deleted hepatocyte growth factor (dHGF), which is designed to promote corneal epithelial regeneration while modulating inflammation and fibrosis.

Claris plans to initiate 2 pivotal, vehicle-controlled studies in the first half of 2027, enrolling approximately 400 patients with LSCD. Unlike the proof-of-concept study, the pivotal trials will use continuous dosing, with visual acuity as the primary efficacy endpoint supported by anatomical assessments.

Currently, no pharmacologic treatments are approved for LSCD.