An Evaluation of Therapeutic Noninferiority of 0.005% Latanoprost Ophthalmic Solution and Xalatan in Patients With Glaucoma or Ocular Hypertension

Maurizio Digiuni, MD; Gianluca Manni, MD; Michele Vetrugno, MD; Maurizio Uva, MD; Giovanni Milano, MD; Nicola Orzalesi, MD; Paolo Fogagnolo, MD; Marco Centofanti, MD; Emilio Campos, MD; Luca Rossetti, MD

Disclosures

J Glaucoma. 2013;22(9):707-712. 

In This Article

Abstract and Introduction

Abstract

Purpose: To assess the therapeutic noninferiority of 0.005% latanoprost ophthalmic solution versus Xalatan in the treatment of patients with primary open-angle glaucoma or ocular hypertension.

Patients and Methods: This was a double-masked, randomized, multicenter study. A total of 184 patients with a diagnosis of unilateral or bilateral primary open-angle glaucoma or ocular hypertension were randomly assigned to either 0.005% latanoprost ophthalmic solution or Xalatan for 12 weeks. The primary end-point was the change in intraocular pressure (IOP) at 12 weeks in the 2 groups. Noninferiority was reached if the 2-sided 95% confidence intervals (CI) for the difference between adjusted treatment means were entirely within the interval from −1.5 to +1.5 mm Hg.

Results: The difference between treatments in the change of IOP from baseline to the end of treatment was 0.12 mm Hg (95% CI: −0.47, 0.71) in the intention-to-treat population and 0 mm Hg (95% CI: −0.58, 0.57) in the per protocol population. There was no statistically significant difference between the 2 groups in terms of drug-related adverse events. The most commonly reported drug-related local adverse events were: ocular hyperemia, eyelashes growth, and eye irritation.

Conclusions: This study demonstrates that 0.005% latanoprost ophthalmic solution is noninferior to Xalatan in lowering IOP and is generally well tolerated.

Introduction

Glaucoma is a chronic disease characterized by visual field loss associated with optic nerve damage.[1] It can lead to blindness if left untreated and occurs in approximately 1% to 2% of the population over 40 years, rising up to 5% after the age of 70.[1] Primary open-angle glaucoma (POAG) is the most prevalent form. Ocular hypertension (OH) is defined as a raised intraocular pressure (IOP) above normal that has not resulted in demonstrable visual field or optic nerve head damage. Lowering IOP has been proven effective in slowing the progression of POAG and reducing the conversion from OH to POAG.[2–4]

Prostaglandin analogs are a class of drugs with a proven safety and efficacy for controlling IOP.[5,6] Latanoprost is an analog of prostaglandin F2[alpha]; studies on humans indicate that the peak concentration in the aqueous humor is reached about 2 hours after topical administration; only a negligible amount of the active acid of latanoprost reaches the systemic circulation.[7–9] Latanoprost has been found to be more effective than timolol in reducing IOP[10,11] and similarly effective to other prostaglandin analogs.[12]

In a number of countries generics of latanoprost are now available. Unfortunately clinical trials comparing the efficacy of the brand product with the generic equivalent drug are very seldom carried out, and what usually happens is that both patients and doctors are left without any evidence of efficacy and safety of the drugs they are using. In the specific case of the generic of latanoprost there are 2 comparative trials, and whereas one reports a noninferiority,[13] the other shows a significant reduced effect of the generic as compared with the original Xalatan.[14]

A new formulation of 0.005% latanoprost ophthalmic solution (Galaxia, Alfa Intes srl, Italy) has recently become available. The aim of this multicenter clinical trial was to verify the therapeutic noninferiority of 0.005% latanoprost ophthalmic solution versus the reference drug Xalatan (Pfizer Italia srl, Italy) in the treatment of patients with POAG or OH.

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