Purpose: To compare the safety and efficacy of apraclonidine ophthalmic solution 0.25% and 0.5% (both given 3 times daily) to timolol maleate (0.5%) given twice daily, in primary open-angle glaucoma or ocular hypertension.
Methods: This study was a 90-day prospective, multicenter, double-masked, randomized, parallel group trial. Intraocular pressure (IOP) measurements were made between 8:00 and 10:00 AM before the morning dose (i.e., up to 12 hours after the evening dose of glaucoma medication) and at 4:00 PM (i.e., 8 hours after the morning dose of glaucoma medication). Patients with off-therapy IOP of greater than 22 mmHg and less than 35 mmHg were entered into the study and were assessed 14, 30, and 90 days after treatment.
Results: Sixty-nine patients were enrolled; there were no significant demographic differences among the three study groups. All three treatments significantly reduced IOP over 90 days (P < 0.011). For apraclonidine 0.5%, IOP reductions from 25.8 +/- 3.2 mmHg (pretreatment) to 20.4 +/- 4.00 mmHg (day 90) were observed; for apraclonidine 0.25%, from 25.7 +/- 3.05 mmHg (pretreatment) to 22.1 +/- 4.24 mmHg (day 90); and for timolol 0.5% from 26.1 +/- 3.79 mmHg to 21.1 +/- 5.91 mmHg (day 90). The 90-day period of therapy was completed by 12 patients treated with apraclonidine 0.5%, 21 patients treated with apraclonidine 0.25%, and 23 patients treated with timolol 0.5%. There were no serious adverse events. Fourteen of 22 patients (0.5% apraclonidine) and 21 of 23 patients (0.25% apraclonidine) tolerated the drug well; ocular allergy developed in the remaining patients treated with apraclonidine, which resolved upon discontinuation.
Conclusions: Apraclonidine effectively lowers IOP associated with open-angle glaucoma or ocular hypertension; these pilot results will need to be confirmed by a larger pivotal study. Long-term therapy for some patients may be inhibited by ocular allergy for which there was a higher incidence to the 0.5% apraclonidine solution than to the 0.25% solution in this study. Apraclonidine may be of value as an additional therapy for open-angle glaucoma in selected patients.