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May 1993

Maintained Intraocular Pressure Reduction With Once-a-Day Application of a New Prostaglandin F2α Analogue (PhXA41)An In-Hospital, Placebo-Controlled Study

Author Affiliations

From the Department of Ophthalmology, Markusovszky Hospital, Szombathely, Hungary (Drs Rácz, Ruzsonyi, and Nagy), and the Department of Ophthalmology, Columbia University, New York, NY (Dr Bito). Dr Bito has a proprietary interest in the development of prostaglandins, their analogues, and prodrugs for the treatment of ocular hypertension and glaucoma, through patents developed, in part, under research grant EY 00333 from the National Eye Institute, Bethesda, Md. The rights associated with these patents have been assigned by Dr Bito to the Trustees of Columbia University, according to National Institutes of Health directives. Dr Bito is also a consultant to Kabi Pharmacia, AB (Sweden), the licensee of these patents and the developer of the drug tested in this study.

Arch Ophthalmol. 1993;111(5):657-661. doi:10.1001/archopht.1993.01090050091036

• To eliminate uncertainties about compliance, 15 patients with glaucoma (intraocular pressure [IOP] >22 mm Hg and <40 mm Hg) were hospitalized to participate in a clinical trial of the ocular hypotensive effectiveness of the new prostaglandin F analogue prodrug, PhXA41 (13,14-dihydro-17-phenyl-18, 19, 20-trinor-PGF2a-isopropyl ester; latanoprost [World Health Organization generic name]). At 9 pm on each of five consecutive days, one of the investigators applied one drop of a 0.006% solution of PhXA41 (representing approximately 2 μg of PhXA41 per treatment) to one eye of nine patients and one drop of placebo to one eye of six patients. This was followed by an evaluation of potential local side effects at 9:30 pm. Complete examinations, including tonometry (Goldmann), were also performed at 8 am and 8 pm on days 1 to 6, as well as at noon and 4 pm on days 1, 2, and 6. Except for mild conjunctival hyperemia in two PhXA41-treated eyes (once each at 8 am), no side effects were observed or reported by any patient. Starting with the first IOP measurement after the first treatment (8 am on day 2), IOP was reduced by 20% to 30% in the eyes treated with PhXA41. This reduction was highly significant (P<.01 at 12 time points and P<.05 at the remaining two measurements) throughout the study. The IOP reduction did not become attenuated during the 23 hours after treatments. At 11 hours after the last treatment, the mean (±SD) IOP difference between PhXA41-treated and contralateral control eyes was −5.5±2.8 mm Hg, as compared with −6.1±1.8 mm Hg 12 hours later. PhXA41 must, therefore, be regarded as an excellent candidate for use as a once-a-day glaucoma medication.