Aims:

1. To assess the feasibility of switching a large group of patients on treatment with latanoprost to travoprost.
2. To assess the efficacy and safety of travoprost compared to latanoprost after the switch.

Intraocular pressure (IOP) is currently the only proven modifiable risk factor in the management of glaucoma.1 Either medical or surgical management can achieve the control of IOP. Prostaglandin analogs are the newer class of drugs among the various topical ocular hypotensive medications, with a proven safety and efficacy for controlling IOP.2 Their potency and once a day dosing and lower incidence of systemic side effects have made them popular for use as monotherapeutic and first-line agents. They include latanoprost, bimatoprost, travoprost and unoprostone. All of them have a similar molecular structure and they work by increasing the aqueous drainage via trabecular meshwork and the uveoscleral pathway.3 It has been shown that the efficacy of latanoprost, bimatoprost and travoprost in reducing IOP in ocular hypertension and primary open angle glaucoma is comparable.4 Conjunctival hyperemia is one of the most common ocular side effects. There has been a reported higher incidence of hyperemia with bimatoprost and travoprost as compared to latanoprost.4 However, this hyperemia is usually benign and usually abates as the drug is used long term. The incidence of discontinuation of therapy due to hyperemia is very low and not different among the various prostaglandins.5 Among the prostaglandin analogues, latanoprost has been the market leader in Singapore for the past few years. However, the Singapore National Eye Center (SNEC) pharmacy recently accepted tenders from various drug companies for prostaglandin analogs. Alcon, the manufacturer of travoprost was awarded the tender. Since then, all subsidized patients previously treated with latanoprost were systematically switched to travoprost and this process will continue for the rest of this year. The switch is a systematic switch and is not based on intolerance or poor response to latanoprost.

To date, there has been a single report regarding the feasibility and efficacy of a mass switch from latanoprost to bimatoprost.5 The study reported a high switch rate and good IOP control with minimal switch back. However, similar data on switching from latanoprost to travoprost is lacking. In this study, we propose to prospectively study the efficacy and safety of switching from latanoprost to travoprost in a large series of glaucoma patients at SNEC. A total of 372 consecutive patients being switched from latanoprost to travoprost will be followed up for 12 weeks following the switch. In addition to IOP, safety and tolerability (with particular emphasis on hyperemia) of travoprost will be examined.

References:

1.Leske MC, Heijl A, Hussein M et al. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol.

2003 Jan;121(1):48-56. 2.Alexander CL, Miller SJ, Abel SR. Prostaglandin analog treatment of glaucoma and ocular hypertension. Ann Pharmacother. 2002 Mar;36(3):504-11.3. 3.Eisenberg DL, Toris CB, Camras CB. Bimatoprost and travoprost: a review of recent studies of two new glaucoma drugs. Surv Ophthalmol. 2002 Aug;47 Suppl

1:S105-15. 4.Parrish RK, Palmberg P, Sheu WP; XLT Study Group. A comparison of latanoprost, bimatoprost, and travoprost in patients with elevated intraocular pressure: a 12-week, randomized, masked-evaluator multicenter study. Am J Ophthalmol. 2003 May;135(5):688-703.

5.Law SK, Song BJ, Fang E, Caprioli J. Feasibility and efficacy of a mass switch from latanoprost to bimatoprost in glaucoma patients in a prepaid Health Maintenance Organization. Ophthalmology. 2005 Dec;112(12):2123-30.