Intraocular Pressure-reducing Effect of PhXA41 in Ocular Hypertension: Comparison of Dose Regimens

Purpose: To investigate the intraocular pressure (IOP)-reducing effect and side effects of PhXA41, a new prostaglandin F 2α (PGF 2α ) analog, in ocular hypertension and to compare two different dose regimens of PhXA41. Methods: This was a 2-week randomized, placebo-controlled, double-masked study. PhXA41 eye drops at a concentration of 0.006% (60 µg/ml) were administered either once daily (evening) or twice daily (morning and evening) to patients with bilateral ocular hypertension. Each PhXA41 group consisted of 20 patients and the placebo group consisted of 10. Results: PhXA41, administered once or twice daily, reduced IOP by 8.9 and 7.1 mmHg, respectively, in the two treatment groups at the end of the 2-week treatment period. No clear-cut drift in the IOP reduction was observed during the treatment period, but the maximum response was obtained on day 2 in the group receiving PhXA41 twice daily. Both dose regimens of PhXA41 caused more conjunctival hyperemia than the placebo. At the end of the treatment period, 64% to 74% of the patients receiving PhXA41 exhibited no or barely detectable hyperemia. The corresponding figure in the placebo group was 90%. PhXA41 was well tolerated and only one patient dropped out of the study. Conclusions: PhXA41 reduced IOP by 28% to 36% in patients with ocular hypertension with only mild side effects. Dosing once daily was at least as effective as twice daily. PhXA41 has the potential of becoming a useful new drug for glaucoma treatment.