Study to Evaluate the Safety and Efficacy of SDP-4 in Subjects With Dry Eye Disease (DED)

Inclusion Criteria: * Have DED in both eyes for ≥ 6 months prior to Visit 1/Screening. * Total score ≥ 40 on the SANDE questionnaire. * Tear break-up time (TBUT) of ≤ 6 seconds in both eyes. * Anesthetized Schirmer's test tear volume ≥ 4 mm and \<10 mm in both eyes. Exclusion Criteria: * Ocular surface corneal disease, other than DED. * Lid margin disorder other than meibomian gland dysfunction (MGD). * Any previous reconstructive or cosmetic eyelid surgery that may affect the normal function of the lids * Any previous invasive glaucoma and/or corneal surgery * Corneal refractive surgery in the 12 months prior to Visit 1/Screening. * Cataract extraction within 90 days prior to Visit 1/Screening. * Use of ophthlamic corticosteroids, NSAIDs, antibiotics, antihistamines, IOP lowering medication, in the 30 days prior to Visit 1/Screening * Serious systemic disease or uncontrolled medical condition that in the judgment of the Investigator could confound study assessments