Objective: To evaluate safety and efficacy of topical ophthalmic tofacitinib (CP-690,550), a novel Janus kinase inhibitor, in treating dry eye disease (DED). Design: A phase 1/2 prospective, randomized, double-masked, multicenter, vehicle- and comparator-controlled trial (NCT00784719). Participants: Patients (n = 327) 18 years of age and older with a DED diagnosis for 6 months or more. Methods: Tofacitinib (0.0003% twice daily, n = 46; 0.001% in both eyes twice daily, n = 47; 0.003% twice daily, n = 48; 0.005% twice daily, n = 48; 0.005% once daily, n = 44) results were compared with those of groups receiving active treatment cyclosporine ophthalmic emulsion 0.05% twice daily (n = 47) and vehicle twice daily (n = 47). Safety and efficacy evaluations were performed at baseline and throughout the 8-week study. Main Outcome Measures: Schirmer wetting, corneal staining, tear film break-up time, conjunctival staining, Ocular Comfort Index (OCI), and Ocular Surface Disease Index (OSDI). Results: All tofacitinib doses were well tolerated, exhibiting better patient-reported ocular tolerability than cyclosporine. For the proportion of patients achieving 10 mm or more Schirmer wetting (without anesthesia) at week 8 (primary end point), greater response rates were observed in the tofacitinib 0.001% twice daily (27.3%), 0.005% twice daily (25.5%), and 0.005% once daily (26.1%) groups versus vehicle (20.0%); however, the differences were not statistically significant. Mean increase in Schirmer wetting (without anesthesia) from baseline was statistically significant (P<0.2, 2-sided) for all tofacitinib doses (1.7-3.1 mm), cyclosporine (3.9 mm), and vehicle (1.4 mm). For corneal staining (total score), significant improvement (reduction) from baseline was observed for all tofacitinib doses (-0.9 to -1.9) and vehicle (-2.0), but not for cyclosporine. The proportion of patients with complete corneal clearing (CCC; 100%) at week 8 was greatest with tofacitinib 0.005% once daily (15.9%) versus vehicle (6.7%). Symptom scores (OCI, OSDI) at week 8 showed significant improvements from baseline for all tofacitinib groups, and tofacitinib demonstrated greater improvements than cyclosporine. The tofacitinib 0.005% once daily group showed significant improvements in both a sign (Schirmer wetting without anesthesia) and symptom (OSDI environmental triggers subscale) versus vehicle and also demonstrated the highest response rate for CCC (16.7%) at week 8. Conclusions: This phase 1/2 study of tofacitinib demonstrated a trend for improving both signs and symptoms of dry eye. All doses of tofacitinib exhibited a reasonable safety profile and were well tolerated by patients with DED. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2012 American Academy of Ophthalmology.