An evaluation of the rate of nonresponders to latanoprost therapy.

PURPOSE: To determine the proportion of patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH) who do not respond to latanoprost therapy.

METHODS

Three hundred forty consecutive patients with a new diagnosis of POAG or OH, or previously treated only with a beta-blocker and after an appropriate washout period, were treated with latanoprost for 1 month and then divided into three groups on the basis of the reduction in intraocular pressure (IOP): nonresponders (<15%), responders (> or =15% but <30%), and high-responders (> or =30%). To give a wide picture of the drug effect, eight different cut-off points were used to present data on distribution of mean IOP reductions. Only the nonresponders entered a randomized cross-over study investigating the efficacy of timolol, brimonidine, and pilocarpine.

RESULTS

IOP at baseline and after 1 month's latanoprost therapy was respectively 24.1+/-1.4 and 16.9+/-2.4 mm Hg, with a mean reduction in IOP of 29.9+/-4.2%. Nonresponders accounted for 4.1% of the patients and high-responders for 41.2%. The nonresponders showed a statistically significant reduction in IOP after brimonidine treatment (P=0.05), whereas the reduction after timolol and pilocarpine treatment was clinically relevant but not statistically significant.

CONCLUSIONS

This multicenter prospective study found only 14 of 340 nonresponders to latanoprost. In the cross-over trial on nonresponders, IOP reduction reached statistical significance only after brimonidine, but their small number reduced its statistical power.