Determine safe, effective, iontophoretic dose(s) of EGP-437 (dexamethasone phosphate formulated for iontophoresis) in patients with noninfectious anterior uveitis; evaluate systemic drug exposures. Prospective, phase I/II, multicenter, double-masked, parallel group, randomized clinical trial. Forty outpatients with anterior uveitis. Forty of 42 randomized patients received an iontophoresis treatment in 1 qualifying eye and completed the study. Patients were randomized into 1 of 4 iontophoresis dose groups (1.6, 4.8, 10.0, or 14.0 mA-min), treated with EGP-437 via the EyeGate II Delivery System (EGDS), and followed until day 28. The main outcome measures were anterior chamber cell (ACC) scores at days 14 and 28; time to ACC score of zero; proportion of patients with an ACC score reduction from baseline of ≥ 0.5 at day 28; mean change from baseline in ACC score at day 28; and the systemic exposures of dexamethasone and dexamethasone phosphate after EGP-437 treatment with the EGDS. After a single EGP-437 treatment, 19 of 40 patients (48%) achieved an ACC score of zero at day 14. By day 28, 24 of 40 patients (60%) achieved an ACC score of zero. A Kaplan-Meier analysis demonstrated that the 1.6 mA-min dose was the most effective and revealed an inverse dose response; median days to an ACC score of zero were 11.5 days in the 1.6 mA-min group versus 31 days in the 14.0 mA-min group. Twenty-six patients (65%) had an ACC score reduction from baseline of ≥ 0.5 at day 28. The mean change in ACC score from baseline to day 28 was -2.14 with a median of -2.00. Throughout the study, the mean intraocular pressure remained within normal range and mean best-corrected visual acuity at 4 meters remained relatively stable. Most adverse events were mild; no serious adverse events were reported. Pharmacokinetics results showed low short-term systemic exposure to dexamethasone after iontophoresis; no nonocular systemic corticosteroid-mediated effects were observed. Approximately two thirds of the patients reached an ACC score of zero within 28 days, after only receiving 1 iontophoresis treatment. The lower doses seemed to be the most effective, and treatments were well-tolerated. Proprietary or commercial disclosure may be found after the references.