Neil Osterweil

July 04, 2016

BOSTON — For patients with open-angle glaucoma or ocular hypertension, the investigational antiglaucoma agent latanoprostene bunod (Bausch & Lomb) offers significantly better control of intraocular pressure than the beta-blocker timolol maleate, according to a pooled analysis of two phase 3 studies.

At each follow-up point, intraocular pressure was at least 1 mm Hg lower in patients treated with latanoprostene bunod than in those treated with timolol, reported Murray Fingeret, OD, chief of the optometry at the Department of Veterans Administration New York Harbor Health Care System in New York City.

The improvement seen with latanoprostene bunod over current therapies is incremental rather than evolutionary, but is a step in the right direction, he told Medscape Medical News.

In fact, current treatments for open-angle glaucoma do not address one of the mechanisms that lead to the condition, he said.

Patients with open-angle glaucoma have lower levels of nitric oxide synthase activity in the trabecular meshwork, Schlemm's canal, and ciliary muscle, and fewer nitric oxide metabolites in the aqueous humor.

Latanoprostene bunod is a nitric-oxide-donating prostaglandin F2-alpha analog that is metabolized in situ to latanoprost acid, a prostaglandin agent, which enhances uveoscleral outflow. It is also a nitric oxide donor compound (soluble guanylyl cyclase) that increases outflow through the trabecular meshwork and Schlemm's canal.

"Nitric oxide lowers IOP in normal and primary open-angle glaucoma eyes. A major site of action for nitric oxide donors is in the trabecular meshwork and Schlemm's canal," Dr Fingeret explained.

He presented the results of the analysis here at Optometry's Meeting by the American Optometric Association.

Two previous phase 3 randomized double-masked clinical trials compared a single daily dose of latanoprostene bunod 0.024% drops with timolol maleate (Timoptic and generics) 0.5% twice daily in patients with primary open-angle glaucoma or ocular hypertension, as reported by Medscape Medical News.

Of the 774 patients who completed 3 months of treatment in one of these two studies, 523 were treated with latanoprostene bunod and 251 were treated with timolol.

Baseline intraocular pressure was similar in the latanoprostene bunod and timolol groups (26.7 vs 26.5 mm Hg).

In the pooled intention-to-treat analysis, mean diurnal decrease from baseline in the study eye — the primary end point — was significantly greater at 3 months in the latanoprostene bunod group than in the timolol group (32.0% vs 27.6%; P < .001).

In addition, reductions in intraocular pressure were significantly greater in the latanoprostene bunod group than in the timolol group at 8 am, 12 pm, and 4 pm during visists at week 2, week 6, and month 3 (P < .001).

Treatment-related ocular adverse events were more common with latanoprostene bunod than with timolol (17.0% vs 11.1%). The most common events were conjunctival hyperemia, eye irritation, eye pain, ocular hyperemia, dry eye, foreign-body sensation, and blurred vision. No nonocular treatment-related adverse events occurred in more than 1.5% of patients in either group. Vital signs, ocular signs, and best-corrected visual acuities were comparable in the two groups.

One Small Step Against Glaucoma

"This is not taking your eye pressure down to another dimension, but it's another point, and if you have a similar side-effect profile to latanoprost and you can get an extra point, it could be useful," Dr Fingeret said.

With glaucoma, any degree of safe pressure lowering with one-bottle convenience is worthwhile.

"If we get to the point where we can get down to one drug that can do what we had to do previously by adding another drug — to get the IOP down by an extra couple of points — compliance goes up. It's all about compliance," said Fred Goldberg, OD, from McLean Eyecare in McLean, Virginia.

Dr Goldberg told Medscape Medical News he would have liked to have seen latanoprostene bunod compared with another prostaglandin-based agent, but Dr Fingeret explained that timolol was the comparator required for registration trials by US Food and Drug Administration (FDA) regulations.

"Glaucoma is an intriguing disease, and we still don't know a whole lot about it," said session moderator Dominick Maino, OD, professor of pediatrics and binocular vision at the Illinois College of Optometry and Illinois Eye Institute in Chicago.

In fact, "the treatment, as Dr Fingeret pointed out, hasn't changed a whole lot over the decades. This does have the possibility of presenting one more way, one more option for controlling the disease to make sure that our patients respond so that they can see better and longer throughout their lifetimes," he told Medscape Medical News.

The FDA is expected to announce its decision to approve or deny approval of the drug on July 21.

The trials were funded by Bausch & Lomb. Dr Fingeret is a consultant for Bausch & Lomb. His coauthor, Jan Vittilow, is an employee of Bausch & Lomb. Dr Goldberg is on the speakers bureau for Alcon. Dr Maino has disclosed no relevant financial relationships.

Optometry's Meeting by the American Optometric Association (AOA): Poster 30. Presented July 2, 2016.

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