Blood Concentrations of Cyclosporin A During Long-Term Treatment With Cyclosporin A Ophthalmic Emulsions in Patients With Moderate to Severe Dry Eye Disease

To quantify blood cyclosporin A (CsA) concentrations during treatment with CsA topical ophthalmic emulsions, blood was collected from 128 patients enrolled in a Phase 3, multicenter, double-masked, randomized, parallel-group study of CsA eyedrops for treatment of moderate to severe dry eye disease. Patients received 0.05% CsA, 0.1% CsA, or vehicle b.i.d. for 6 months; vehicle-treated patients then crossed over to 0.1% CsA b.i.d. for 6 months. CsA concentrations were measured using a validated LC/MS-MS assay (quantitation limit = 0.1 ng/mL). No patient receiving 0.05% CsA had any quantifiable CsA in the blood (n = 96 samples). All but 7 of 128 (5.5%) trough blood samples from the 0.1% CsA group were below the quantitation limit for CsA; none exceeded 0.3 ng/mL. CsA was also below the limit of quantitation in 205 of 208 (98.6%) of serial postdose blood samples collected from 26 patients during 1 dosing interval between months 9 and 12. The highest Cmax measured, 0.105 ng/mL at 3 hours postdose, occurred in a 0.1% CsA-treated patient. These results indicate that long-term use of topical CsA ophthalmic emulsions at doses that are clinically efficacious for treating dry eye will not cause any system-wide effects.