A sustained-release eyedrop formulation of pilocarpine,PilaSite, has proceeded into a second Phase III trial fortreatment of glaucoma, InSite Vision Inc. announced this week.

The drug is incorporated into the company's DuraSite drug-delivery system, which gradually releases the drug into the eyeover several hours. InSite of Alameda, Calif., explained thatalthough pilocarpine has been used for more than a century totreat glaucoma, patient compliance generally is poor due to thehigh dosing frequency (usually four times daily) and adverseside effects. PilaSite eyedrops are being tested at half thedosing frequency of regular pilocarpine eyedrops.

InSite's first Phase III trial involved 200 patients who receivedeither 2 percent PilaSite eyedrops twice daily or 2 percentpilocarpine eyedrops four times daily. The company reportedthat PilaSite appeared to be as effective as the conventionaleyedrops in controlling elevated intraocular pressure andproduced fewer drug-related side effects. The second Phase IIIstudy will also include 200 patients with ocular hypertensionor open-angle glaucoma. InSite said it expects to file a newdrug application in 1995.

Pharmos Corp. is in Phase II testing with a submicron emulsion(SME) formulation of pilocarpine (see BioWorld, Feb. 9). Thisslow-release formulation is also designed for twice-dailyadministration to reduce the side effects of standardpilocarpine.

InSite's BetaSite, a sustained-release eyedrop formulation ofthe beta-blocker levobunolol, is also in Phase III clinicals fortreatment of chronic glaucoma. BetaSite acts by reducing theproduction of fluid in the eye, while PilaSite increases theoutflow of fluid from the eye. InSite (NASDAQ:INSV) noted thatthe active ingredients in both drugs are often prescribed asconcomitant therapies to maximize the reduction of intraocularpressure. The company is pursuing each product separately. --Brenda Sandburg

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