Efficacy and Comfort of Olopatadine Versus Ketotifen Ophthalmic Solutions: A Double-Masked, Environmental Study of Patient Preference

Andrea Leonardi; Panayotis Zafirakis


Curr Med Res Opin. 2004;20(8) 

In This Article

Summary and Introduction

Background: Ocular allergies cause itching, redness, chemosis, tearing, and swelling of the eyelids in sensitized individuals. The options available for treatment of ocular allergy include olopatadine 0.1% (Opatanol; Patanol [US]*) and ketotifen 0.025% (Zaditen; Zaditor [US]†). Patient preference for an eye drop can often be a primary factor in determining the level of compliance and satisfaction with any given therapy.
Objective: This study sought patient perspective on eye drop efficacy in controlling signs and symptoms of allergic conjunctivitis and eye drop comfort. Also evaluated were the factors considered by patients when making decisions of preference.
Methods: One hundred patients with previous history and current symptoms of seasonal or perennial allergic conjunctivitis were enrolled at two centers (Athens, Greece, N = 50; Padova, Italy, N = 50) for this two visit, double-masked study. Qualified patients received two masked bottles of medication (one olopatadine, one ketotifen) and were asked to use both medications as needed over the course of four weeks, but not to exceed usage of two drops of medication per eye per day. At the second visit, patients answered five questions comparing the two masked medications in terms of preference, drop comfort, and efficacy in treatment of signs and symptoms. Patients also defined the factors upon which they based these decisions.
Results: A significantly greater percentage of patients (81%) selected olopatadine when asked which medication they preferred; which they found more comfortable; which they found more efficacious in reducing symptoms of allergy; and which they would select if visiting the doctor's office (P < 0.0001). Seventy-six percent (76%) of patients considered both efficacy and comfort when making their preference decisions (P < 0.0001). No adverse events were volunteered or elicited.
Conclusion: In this study, patients preferred to use the anti-allergy eye drop olopatadine over ketotifen after using both drops and evaluating relative efficacy and comfort during the course of four weeks. A significantly greater percentage of the patients preferred to use olopatadine during the study period, found it more efficacious and comfortable, and would select olopatadine if visiting their doctor's office during allergy season.

Ocular allergies occur when sensitized individuals are exposed to specific airborne allergens. An allergen, once it has reached the eye, binds to IgE on conjunctival mast cells triggering a cascade of reactions resulting in the release of histamine and other allergic and inflammatory mediators from the mast cell. Histamine is the primary mediator released, and the only mediator that has been shown to cause the entire spectrum of signs and symptoms of ocular allergy (itching, redness, chemosis, lid swelling, and tearing). Itching is the hallmark symptom of ocular allergy, and can impact patients' ability to go about daily functions, while the redness and lid swelling of allergy are the predominant signs of allergy and can cause concern about appearance, as well as discomfort.[1]

The incidence of allergy (rhinoconjunctivitis) in Europe has been assessed by various recent epidemiological studies to be present in 10 to over 22% of the general population in several European countries.[2,3,4,5] The International Study of Asthma and Allergies in Childhood (ISAAC) revealed a maximum of 54.4% of 13-14 year olds at 155 centers having had hay fever, however this study also indicated that the prevalence of allergic rhinoconjunctivitis varies widely amongst age groups and geographical areas.[6] Centers having the highest prevalence were scattered throughout the world with no distinct geographical pattern. In addition, it has been noted that the incidence of allergy is rising and that urban/industrialized areas with elevated levels of air pollutants may lead to increased susceptibility toward allergens.[7]

Factors that may aid in improving the treatment of ocular allergy in Europe include recognizing the patient population in need of treatment, and assigning the appropriate treatment for each individual patient's needs. The majority of anti-allergy medication used in many European countries is either systemic or consists of older options such as antihistamine eye drops (naphazoline, antazoline, levocabastine) or older-generation mast cell stabilizers (cromoglycates). Recently, newer options for anti-allergy eye drops have also become available in Europe. Olopatadine hydrochloride 0.1% (Opatanol; Patanol (US)) is indicated for the treatment of signs and symptoms of allergic conjunctivitis (itching, redness, chemosis, lid swelling and tearing).[8] Ketotifen fumarate 0.025% (Zaditen; Zaditor (US)), while the indication does vary by market, is indicated in Italy and Greece for the signs and symptoms of seasonal allergic conjunctivitis, including eyes or lids suffering from itching, watery discharge, redness, and swelling.[9]

Olopatadine is an H1 receptor specific antihistamine and mast cell stabilizer that inhibits the immediate hypersensitivity reaction. Olopatadine was developed specifically as an ophthalmic agent for use in the human conjunctiva, and it has demonstrated the ability to stabilize human conjunctival mast cells both in vitro and in vivo.[10,11] In clinical trials, olopatadine has demonstrated efficacy for at least 12 hours in the Conjunctival Allergen Challenge (CAC) Model.[12]

Ketotifen, originally a molecule used in asthma treatment, works via a mechanism with antihistaminic and mast cell stabilizing effects. It has shown a duration of action up to 12 hours in reducing ocular itching in the CAC clinical model and has a favorable safety and tolerability profile.[12,13,14]

The gathering of patient perception data will be important in determining therapy options patients are more satisfied with, therefore increasing the ability of the practitioner to select the primary therapy with greater chances of yielding successful treatment. Novel mechanisms of action can be important advancements, however, the actual success of a therapy can hinge on the selection or recommendation by the medical practitioner. The compliance and satisfaction of patients can be valuable information to the practitioner in making this important decision.

This study sought the patient's perspective on eye-drop efficacy in controlling signs and symptoms of allergic conjunctivitis and comfort, while also taking into account what factors patients considered when making their decisions of preference. The efficacy of ketotifen and olopatadine has been compared in controlled studies,[12,15] and the comfort of olopatadine and ketotifen has been compared previously.[16] The current study compares both efficacy and comfort of olopatadine and ketotifen in an environmental model that allows patients to determine which medication is more effective and comfortable during daily airborne allergen exposure. In this study we use this type of evaluation to determine whether one of two therapy options is significantly preferred by patients for use throughout the allergy season.

* Opatanol and Patanol are registered trade names of Alcon Laboratories, Inc, Fort Worth, TX, USA
† Zaditen and Zaditor are registered trade names of Novartis Pharmaceuticals, East Hanover, NJ, USA


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