The purpose of this study is to determine the safety, tolerability and pharmacokinetics of R348 eye drops in patients with dry eye disease.

This is a randomized, double-blind, placebo-controlled single and multiple ascending dose study to evaluate the ocular tolerability, safety, and pharmacokinetics of R348 administered in patients with mild to moderate keratoconjunctivitis sicca (KCS).

Inclusion Criteria:

• Mild to moderate Keratoconjunctivitis Sicca.
• A corrected visual acuity in both eyes of 20/40 or better.
• An intraocular pressure of < 21 mm Hg with a difference between eyes of < 6 mm Hg.

Exclusion Criteria:

• History or evidence of ocular infection, inflammation, or conjunctivitis within 2 months prior to the first dosing day.
• History or evidence of blepharitis requiring the use of antibiotics or eye scrubs within 2 months prior to the first dosing day.
• History of herpes simplex keratitis at any time.
• Current ocular allergy symptoms.
• Recent use of eye medications such as steroids or cyclosporine
• Refractive eye surgery within 12 months of the first dosing day.
• Other eye surgeries within 4 months of the first dosing day.
• Current use of contact lenses or discontinuation of contact lens use within 2 weeks of the first dosing day.
• Receipt of any blood or blood products within 90 days prior to the first dosing day.
• Participation in any clinical study within 30 days prior to the first dosing day.
• History of disease, or currently have a significant illness or abnormal laboratory finding as determined by your study doctor.
• Positive for hepatitis B, hepatitis C or HIV.
• Smoked regularly within 12 months of first dosing day.
• History of substance abuse, drug addiction or alcoholism.