A Phase II Study of STSP-0902 Ophthalmic Solution in Patients With Neurotrophic Keratitis

Inclusion criteria

• Male or female patients aged between 18 to 85 years (inclusive).
• Diagnosed with NK in one or both eyes, with the study eye classified as Mackie Stage 2 (PED) or Stage 3 (corneal ulcer), and with a maximum corneal defect diameter ≥2 mm.
• Reduced or absent corneal sensitivity in the defect area and at least 1 adjacent corneal quadrant, confirmed by: ≤40 mm using the aesthesiometer or cotton swab test demonstrating marked reduction or absence of corneal sensitivity.
• NK duration >2 weeks in the study eye, as confirmed by the investigator based on medical history.
• No improvement in the study eye for ≥7 days prior to randomization.
• Effective non-pharmacological contraception used by the subject (and partner, if applicable) throughout the trial and for 3 months after the last dose, with no plans for pregnancy or gamete donation.
• Voluntarily sign informed consent, with willingness and ability to comply with study procedures, follow-ups, and assessments.

Exclusion criteria

• Any eye with corneal stromal ulceration involving >1/3 of corneal thickness or at risk of corneal melting/perforation.
• Active infection (bacterial, viral, fungal, amoebic, chlamydial) in any eye, or active ocular inflammation unrelated to NK.
• Study eye with other ocular diseases requiring topical medication apart from the prescribed adjunctive treatments during the trial.
• Bilateral vision loss severely impacting daily life, as assessed by the investigator.
• Study eye with Schirmer I test ≤3 mm/5 minutes.
• Severe lagophthalmos, eyelid margin disease, or meibomian gland dysfunction in the study eye that may impair corneal healing or trial outcomes.
• Study eye with any surgery within 3 months prior to randomization (including corneal/non-corneal surgeries affecting trial assessments, except surgeries related to NK etiology), or planned ocular surgery during the trial.
• Study eye with prior surgical intervention for NK (e.g., tarsorrhaphy, conjunctival flap) that may confound efficacy assessments, or amniotic membrane transplantation within 6 weeks prior to randomization.
• Study eye with botulinum toxin injections to the levator muscle within 3 months prior to randomization or planned during the trial.
• Requirement to wear contact lenses during the trial.
• History of inefficacy or poor response to nerve growth factor (NGF) eye drops in any eye.
• Use of autologous serum eye drops, deproteinized calf blood extracts, or other growth factor-containing ocular medications in the study eye(s) planned during the trial.
• Use of NSAIDs, or corticosteroids in the study eye within 1 week prior to randomization or planned during the trial.
• Use of neurotoxic drugs (e.g., antipsychotics, antiepileptics, antihistamines) or systemic immunosuppressants within 4 weeks prior to randomization or planned during the trial, excluding those who have been using it stably for at least 4 weeks before enrollment.
• Poorly controlled systemic or ocular conditions (e.g., diabetic retinopathy, uveitis, autoimmune diseases, malignancies, psychiatric disorders) that may confound efficacy assessments or compliance, as judged by the investigator.
• Known hypersensitivity to the study drug, its excipients, or components of trial-related ophthalmic tests (e.g., fluorescein).
• History of drug abuse or alcohol dependence.
• Participation in another interventional trial (drugs, devices, or vaccines) within 3 months prior to randomization or planned during this trial.
• Female subjects who are pregnant, breastfeeding, or test positive for serum pregnancy; or who are failure to use effective contraception for 2 weeks prior to screening, during the trial, or for 3 months post-dosing.
• Difficulty administering eye drops, venous blood sampling, or history of needle phobia/vasovagal syncope.
• Any other condition deemed unsuitable for trial participation by the investigator.