Predictors of additional intraocular pressure reduction in patients changed to latanoprost/timolol fixed combination

BACKGROUND: Given the growing number of ocular hypotensive medications available, it is important to be able to predict a positive response to therapy. The purpose of the present study was to identify predictors of an additional 10% intraocular pressure (IOP) reduction after 12 weeks of treatment with latanoprost/timolol fixed combination (FC) in patients requiring a change in their previous ocular hypotensive medication. METHODS: This multicenter, open-label, prospective, phase IIIb study included subjects ≥18 years of age with open-angle glaucoma (OAG) or ocular hypertension (OHT). Eligible subjects had baseline IOP ≥21 mmHg and insufficient response to current beta-blocker monotherapy. The primary efficacy analysis (logistic regression) identified predictors of a positive response after 12 weeks of latanoprost/timolol FC. RESULTS: The intent-to-treat (ITT) population included 383 subjects treated with ≥1 drop of FC and having ≥1 follow-up IOP assessment. Mean IOP was 22.19 ± 2.16 mmHg at baseline and was reduced by 5.42 ± 2.71 mmHg at study end. In all, 325 (84.9%) subjects had a positive response to latanoprost/timolol FC; the response rate was similar across groups: OAG (n = 208; 82.7%); OHT (n = 161; 87.6%); OAG+OHT (n = 14; 85.7%). Higher baseline IOP (odds ratio: 1.284; 95% confidence interval [CI]: 1.101, 1.497; p = 0.0014) and absence of adverse events (odds ratio: 0.318; 95% CI: 0.161, 0.629; p = 0.0010) were significant predictors of positive response. Age, gender, ethnic origin, diagnosis, family history of OAG/OHT, corneal thickness, and concomitant systemic beta-blocker were not significant predictors of a positive response in the ITT analysis. The FC was well tolerated. The most common adverse events were related to the eye and were consistent with known adverse events associated with latanoprost and timolol. CONCLUSIONS: These results support the use of latanoprost/timolol FC in patients whose IOP is insufficiently controlled on beta-blocker monotherapy. Patients with higher baseline IOP levels and who do not experience adverse events while on therapy are most likely to achieve a positive response to latanoprost/timolol FC. TRIAL REGISTRATION: Study registration number: NCT00230763