Maintained intraocular pressure reduction with once-a-day application of a new prostaglandin F2 alpha analogue (PhXA41). An in-hospital, placebo-controlled study
P. Racz, M. R. Ruzsonyi, Z. T. Nagy and L. Z. Bito
Department of Ophthalmology, Markusovszky Hospital, Szombathely, Hungary.
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 F2 alpha 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 micrograms 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.
