Open Label, Prospective, Multicentre Indian Study of Latanoprost in Primary Open Angle Glaucoma and Ocular Hypertension

Indian Latanoprost (Xalatan) Study Group

Aims: To evaluate the intraocular pressure lowering effect and safety of latanoprost 0.005% in patients with primary open angle glaucoma and ocular hypertension.

Patients and Methods: 126 patients with primary open angle glaucoma or ocular hypertension were enrolled in this prospective open label study from 15 centres in India. Patients were treated with latanoprost 0.005% once daily as single therapy for 3 months.

Results: At all the follow-up visits there was a significant reduction in intraocular pressure compared with baseline values (p < 0.05). At 3 months (week 12), a mean intraocular pressure reduction of 9.1± 3.9 mm Hg was obtained. The most frequently reported adverse ocular events were mild congestion (4.2%) and itching (2.5%). Few systemic adverse events were reported.

Conclusion: Latanoprost eye drops showed a marked intraocular pressure lowering effect during the treatment period. The drug was well tolerated and the intraocular pressure lowering effect was stable during the treatment period.


Introduction


Latanoprost (PhXA41; Xalatan^®) is a new phenyl substituted analogue of prostaglandin F2 isopropyl ester that produces an ocular hypotensive effect on topical application for primary open angle glaucoma (POAG) and ocular hypertension (OH). Latanoprost has proven to be an effective ocular hypotensive in healthy eyes and in eyes with elevated intraocular pressure (IOP). Latanoprost has been approved in many countries for the treatment of primary open angle glaucoma and ocular hypertension. This agent reduces IOP by increasing ocular uveoscleral outflow with no effect on aqueous humor production. ^1-3 In phase III studies, latanoprost 0.005% was shown to be an effective IOP reducing agent in patients with POAG or OH during 6 to 12 months of treatment.^4-7

In this open-label, multicentre, non-comparative, prospective study, the efficacy and safety of latanoprost were evaluated in Indian patients with POAG or OH. The purpose of the this study was to evaluate the IOP-reducing effect and tolerability of latanoprost 0.005% eye drops during 12 weeks of treatment.


Patients and Methods


The study was designed as a 3-month open label, multicentre, non-comparative, prospective study, involving 126 patients with POAG or OH at 15 centres across the country. Informed consent was obtained from all patients prior to enrolment.

Patients 18 years aged or older, with unilateral or bilateral POAG or OH, with an IOP of at least 21 mm Hg with previous treatment or 25 mm Hg without treatment were eligible for inclusion. Patients with POAG or OH were enrolled in the study at the discretion of the investigators, according to the manufacturer's indications for latanoprost.

Exclusion criteria included patients with closed or barely open anterior chamber angle or history of angle closure, intraocular surgery within the past 6 months, argon laser trabeculoplasty within the past 3 months, any ocular inflammation or infection within the past 3 months, known hypersensitivity to any component of the study drug, or any condition preventing reliable applanation tonometry. Pregnant women or nursing mothers were also excluded.

Medication and Treatment Schedule
At each visit, the patient was provided with a bottle of latanoprost eye drops, which was sufficient for 1 month. While in use, opened bottles were stored at room temperature (<25° C) The dropper bottles were used within 4 weeks of opening. Patients were instructed to place 1 drop of latanoprost in the affected eye(s) every evening at approximately 8.00 pm.

The treatment period was 3 months. During the 3-month follow-up period, each patient visited the clinic 4 times, as follows: day 0 (visit 1), week 4 (visit 2), week 8 (visit 3), and week 12 (visit 4). At the end of week 12, the patients were exited from the study and treated at the discretion of the investigators.

Efficacy and Safety Variable Evaluation
During every visit, the IOP was measured with a Goldmann applanation tonometer before the pupils were dilated. The same tonometer was used for a given patient at each visit. To minimise diurnal variation, the IOP was consistently measured at the same time of day.

Gonioscopy was performed at the first visit. Visual field acuity and refraction, visual field examination, slit lamp examination, and ophthalmoscopy to evaluate the optic nerve head was performed as clinically required, at the discretion of the investigator. During each visit, patients were evaluated for clinical adverse events. Adverse events were recorded on the case report form (CRF).

Results


126 patients were enrolled in this study. The mean age of the patients was 53.4 ± 12.8 years (range, 32 to 85 years). Sixty six pa-tients (52.4%) were male and 60 (47.6%) were female. The diagnoses were POAG (n = 112) and ocular hypertension (n = 14). The demographic characteristics of the patients are presented in (Table 1).

Table 1. Demographic characteristic of patients receiving latanoprost.

Thirty six patients (28.6%) had concomitant illness, which included hypertension
(7, 5.5%), diabetes mellitus (6, 4.8%), hypertension with diabetes mellitus (4, 3.2%), and bronchial asthma (3, 2.4%). Ten patients (7.9%) had other ocular diseases, which included nuclear cataract, nuclear sclerosis, immature cataract, myopia, and lenticular sclerosis. Six patients (4.8%) had other systemic diseases, which included hypothyroidism, migraine, carcinoma of the mandible, transient ischaemic episodes with diabetes mellitus, and hypertension with ischaemic heart disease. The details of concomitant illness are shown in (Table 2).

Table 2. Concomitant disease frequenc.

The baseline mean IOP was 27.1 ± 6.0 mm Hg. At the end of 4 weeks treatment with latanoprost, the mean IOP was reduced by 7.2 ± 4.1 (26.7%) from baseline (p < 0.05). After 8 weeks of treatment, the mean IOP was reduced by 8.9 ± 4.1 (32.8%) from baseline (p < 0.05). After 12 weeks, the mean IOP was reduced by 9.1 ± 3.9 (33.6%) from baseline (p < 0.05). The mean ± SD changes in IOP are presented in (Table 3) and (Figure 1).

Table 3. Changes in mean intraocular pressure (IOP) after 12 weeks of treatment with latanoprost.