Study: latanoprost more effective than brimonidine

In addition to giving better IOP control, latanoprost was found to be better tolerated in a large multinational study.

Issue: September 15, 2001

PRAGUE, Czech Republic — Latanoprost demonstrated better intraocular pressure (IOP) reduction than brimonidine in a recently concluded European drug study. In addition, latanoprost was better tolerated than brimonidine, reported Hannu M. Uusitalo, MD, PhD, at the International Glaucoma Symposium here.

“It’s fair to say that latanaprost (Pharmacia) used once daily was significantly more effective than brimonidine (Allergan) twice daily in reducing the mean IOP at 6 months,” said Dr. Uusitalo, a docent of ophthalmology at Helsinki University Hospital.

Mean IOP reductions were 7.1 mm Hg for patients who received latanoprost and 5.3 mm Hg for patients who received brimonidine — 28% and 21% reduction, respectively, from the mean pre-study IOP.

“This difference is statistically highly significant,” he said. The difference in IOP reduction was established by week 2 and remained consistent thereafter until the conclusion of the study at month 6.

“If we are targeting to IOP of 17 mm Hg or less, as has been shown to be important in the Advanced Glaucoma Intervention Study, then 41% of patients treated with latanaprost reached that level, while with brimonidine it was 21% of patients reaching that level. I think it is good to remember that these patients were previously on medical therapy and were uncontrolled,” he said.

Study info

A total of 379 patients from several European countries were randomly assigned to receive either latanoprost or brimonidine. The study compared the IOP-lowering effect of latanoprost used once daily with the IOP-lowering effect of brimonidine used twice daily. IOP was measured at baseline, week 2, month 3 and month 6.

Study participants were mostly white women with a mean age of 65 years. Patients with a history of prior use of either study agent or any nonmedical glaucoma treatment were excluded from eligibility. All patients had been diagnosed with unilateral or bilateral glaucoma or ocular hypertension and had previously been on single or dual drug therapy with a resulting IOP of 21 mm Hg or greater. A washout period preceded initiation of study medication.

The study was conducted at sites in Finland, Germany, Ireland, Spain and the United Kingdom.

Responders, reactions, options

Patients were unresponsive to brimonidine at a rate of 32% and were unresponsive to latanoprost at a rate of 7%, Dr. Uusitalo said. In general, about 15% of patients fail to respond to any pressure-lowering drop. “Unresponsive” patients were defined as those whose IOP did not reach a certain percentage of targeted pressure lowering.

Ocular allergy and irritation was seen at a higher rate in the brimonidine arm of the study; there were “twice as many allergic reactions to brimonidine,” he said. Overall, five patients using latanoprost had to be discontinued from therapy and 43 patients were discontinued from brimonidine therapy.

“This difference was mainly due to the fact that that were more dry mouth cases and more cases related to (central nervous system effects) in the brimonidine group than in the latanoprost group,” he said.

New drug options increase clinicians’ need for information about the optimal use of these drugs.

“As a clinician we have very different patients, very different eyes, diseases, glaucomas, patients living in different environments. And that causes a great need for tailoring of medical therapy,” he said.

“However, it is difficult to compare these compounds to each other, and the difficulty is mainly due to the studies. That means in every study, there are different study populations, different designs of the study, different parameters. So actually we need this kind of head-to-head comparison, comparisons between the compounds.”

For Your Information:

Hannu M. Uusitalo, MD, PhD, can be reached at Silmakkeenkatu 1 B 8, Tampere, Finland; (358) 2-247-5111; fax: (358) 3-253-5293; e-mail: hannu.uusitalo@uta.fi.

Pharmacia, maufacturers of Xalatan (latanoprost), can be reached at 100 Route 206 North, Peapack, NJ 07977; (908) 901-8592. Allergan, manufacturers of Alphagan (brimonidine tartrate) can be reached at 2525 Dupont Drive, Irvine, CA 92612; (800) 433-8871; fax: (714) 246-5913; Web site: www.allergan.com.