By Cameron Johnston
FORT LAUDERDALE, Fla -- April 30, 2008 -- One of the largest and longest safety trials ever conducted using an ocular hypotensive drug has demonstrated no increased risk of harmful side effects when the fixed-dose combination of latanoprost and timolol is used to treat open-angle glaucoma or ocular hypertension, it was reported here at the 2008 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO).
In this study, 974 patients began treatment with a once-daily fixed-dose combination of latanoprost and timolol. Patients were evaluated at a total of 11 clinic visits spaced approximately 6 months apart. All patients had glaucoma that was not controlled adequately with timolol or another agent alone. Prior prostaglandin use was not permitted.
After a mean follow-up of approximately 5 years, 23.9% of patients had at least some increase in iris pigmentation, while 61% had none. Increased iris pigmentation is a well-known side effect with latanoprost, which resolves if the drug is discontinued. Only 8 patients in total had what was considered "marked" iris pigmentation, while the others had either mild or moderate.
A further side effect with latanoprost, also well documented, is an increase in eyelash length and thickness. In this study, 463 patients (47.5%) reported an increase in eyelash length.
The other side effect that was measured was the increase in periorbital darkening, a condition in which the patient appears to have a suntan around the eyes. This occurred in 51 patients, of whom 39 had darkening around both eyes.
These side effects were not unexpected, said John Grunden, PhD, Senior Investigator, Pfizer, Inc., New York, New York, which produces latanoprost and the fixed-dose combination of latanoprost and timolol. Dr. Grunden noted that all of these side effects are asymptomatic and are purely cosmetic.
The fixed-dose combination of latanoprost and timolol was shown in this study to be safe and effective, said Dr. Grunden, and the side effects were not serious, nor were they sufficient to make the patients want to switch to another drug.
The spectrum of side effects from other ocular hypotensive drugs has led scores of patients with glaucoma to stop using their medications within the first year, so any drug that is able to demonstrate minimal side effects should increase the likelihood of patient compliance, Dr. Grunden concluded.
Funding for this study was provided by Pfizer, Inc.
[Presentation title: 5-Year, Multicenter Safety Study of Fixed-Combination Latanoprost/Timolol (Xalacom) for Open-Angle Glaucoma (OAG) and Ocular Hypertension (OH). Abstract A64]
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