Effectiveness of Glaucoma Drugs Similar in Trials and 'Real Life'

By Gabriel Miller

February 06, 2014

NEW YORK (Reuters Health) - Eye drops to lower intraocular pressure are as effective in real-life use as they are among clinical trial subjects, a new study suggests.

The study is important because it clarifies the actual effect of these drugs for patients, as opposed to the drug's efficacy within the "artificial construct of a clinical trial," said lead author Dr. Henry Jampel, a professor of ophthalmology at Johns Hopkins Hospital in Baltimore, Maryland.

"In the real world setting, the effectiveness is likely to be a lot less than in a clinical trial, in which the patient is carefully monitored, constantly encouraged to use (the) medication, and is especially eager to please the doctor," Dr. Jampel told Reuters Health in an email. "However, in our study, with these particular patients using these particular medications, the effectiveness of the eye drops did not appear to be worse than in a clinical trial."

The study also has implications for how physicians manage patients with glaucoma. Dr. Ivan Goldberg, the head of the glaucoma unit at Sydney Eye Hospital in Sydney, Australia, said that doctors who prescribe drugs to lower intraocular pressure frequently prescribe three or more of these drugs simultaneously, even though there are few studies that characterize how these drugs work in combination.

"This study, by cleverly utilizing a 'reverse therapeutic trial,' reinforces clinicians' impressions of how agents add intraocular pressure-reducing power to one another," Dr. Goldberg said in an email. He was not involved with the study.

The study included 603 patients with primary open-angle glaucoma seen at seven different medical centers in the U.S. They could be on up to three drugs, including prostaglandin analogues, beta-adrenergic antagonists, carbonic anhydrase inhibitors, or -adrenergic agonists.

Patients' intraocular pressure was measured and then they underwent a washout period for a minimum of 5 days for carbonic anhydrase inhibitors, 14 days for alpha-adrenergic agonists, and 28 days for all other eye drugs.

Intraocular pressure was then remeasured.

Following the washout period, intraocular pressure increased by a mean of 5.4, 6.9, and 9.0 mmHg for those using 1, 2, and 3 medications, respectively.

Dr. Paul Lee, the chair of ophthalmology at the University of Michigan in Ann Arbor, Michigan, said in an email that these results support the practice of combining glaucoma drugs "since each additional medication does have a beneficial impact."

Dr. Lee was not involved with the study.

The investigators compared the effectiveness of the drugs used in the study with the efficacy reported in two clinical trials of prostaglandin analogues and a meta-analysis of patients taking combination of drugs and found the effect was similar in their study.

Full results were published online January 30 in JAMA Ophthalmology.

SOURCE: http://bit.ly/1fOBvgL

JAMA Ophthalmol 2014.

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