A Phase 2 Trial to Test Safety and Efficacy of ST-100, a Unique Collagen Mimetic Peptide Ophthalmic Solution for Dry Eye Disease

Dry eye disease (DED) is a worldwide source of ocular discomfort. This first-in-human phase 2 clinical study determined the efficacy of treating signs and symptoms of DED using an ophthalmic solution of synthesized mimetic of human collagen (ST-100). This double-masked, randomized, study compared high (60 μg/mL) and low (22 μg/mL) dose ST-100 to vehicle utilizing the Ora, Inc. Controlled Adverse Environment (CAE) during a 28-day period. Participants included males and females ≥ 18 years of age with signs and symptoms of DED for ≥ 6 months that worsened during CAE exposure who were not taking any topical prescription therapeutic. Participants applied ST-100 or vehicle placebo topically to both corneas (1 drop) twice daily via a blow-fill-sealed preservative-free container. The prespecified primary efficacy sign end point was mean change from baseline (CFB) in total corneal fluorescein staining, and the primary symptom end point was mean CFB in ocular discomfort. A secondary prespecified efficacy end point was CFB in unanesthetized Schirmer’s test for tear film production. Of 160 subjects in the intent-to-treat population (112 female, 48 male, median age 64), 146 completed the study. Total corneal fluorescein staining CFB improved for high-dose ST-100, with superiority over vehicle when both eyes were considered together (2-sample t test: P  = 0.0394). High-dose ST-100 was superior to vehicle in Schirmer’s CFB for the study eye (least squares mean difference [confidence interval] = 2.3 [0.6, 4.0], P  = 0.0094). For study eyes, the proportion of Schirmer’s test responders (CFB ≥ 10 mm, Schirmer’s responder rate) was 12.2% for high-dose ST-100 versus 0.0% for vehicle ( P  = 0.0266). The CFB for ocular discomfort score improved in study eyes for high- and low-dose ST-100 (paired t test, P  = 0.0133, P  = 0.0151, respectively) but without superiority over vehicle (ANCOVA: P  = 0.5696, P  = 0.8968, respectively). ST-100 Schirmer’s responders also demonstrated total elimination of worsening of corneal fluorescein stain during the stress of CAE sessions. ST-100 significantly improved tear production and related outcomes in DED and was well-tolerated in reducing symptoms. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.