A current appreciation of sites for pharmacological intervention in allergic conjunctivitis: effects of new topical ocular drugs

PAF-induced inflammatory and immuno-allergic ophthalmic diseases and their mitigation with PAF receptor antagonists: Cell and nuclear effects

Ocular allergies are becoming more prevalent as more airborne pollutants, irritants and microbes pervade our environment. Inflammatory and allergic mediators released by dendritic and mast cells within the conjunctiva cause allergic conjunctivitis (AC), a prevalent ocular surface disorder that affects >40% of the world's human population on a seasonal or perennial basis. Even though histamine is a major culprit, platelet-activating factor (PAF) also contributes to AC, acting either directly or synergistically with histamine and other mediators. PAF receptor-meditated inflammatory reactions, via cell-membrane-bound and nuclear-membrane-bound and nuclear PAF receptors, are also implicated in the etiology of other eye diseases such as uveitis, diabetic retinopathy, corneal and choroidal neovascularization, and age-related macular degeneration which cause serious visual impairment and can lead to blindness. This review highlights the various deleterious elements implicated in the pathological aspects of ocular allergic reactions and inflammation and provides concepts and treatment options to mitigate these eye disorders with a special focus on PAF and PAF receptor antagonists.

Diagnosis, Management, and Treatment of Vernal Keratoconjunctivitis in Asia: Recommendations From the Management of Vernal Keratoconjunctivitis in Asia Expert Working Group

Vernal keratoconjunctivitis (VKC) is an underdiagnosed and underrecognized ocular surface disease with limited epidemiological data in Asia. It is more prevalent in warm, dry, and windy climates, and often has a substantial impact on a patient’s quality of life. In rare cases, VKC can be associated with vision loss, either through corticosteroid overuse or inadequate treatment of persistent inflammation. As a potentially severe and complex disease, there is variability with how VKC is managed across Asia and among the various allergic eye diseases. Diagnosis and treatment of patients with VKC is a challenge for many ophthalmologists, since no precise diagnostic criteria have been established, the pathogenesis of the disease is unclear, and anti-allergic treatments are often ineffective in patients with moderate or severe disease. In addition, the choice of treatment and management strategies used for patients varies greatly from country to country and physician to physician. This may be because of a lack of well-defined, standardized guidelines. In response, the Management of Vernal Keratoconjunctivitis in Asia (MOVIA) Expert Working Group (13 experts) completed a consensus program to evaluate, review, and develop best-practice recommendations for the assessment, diagnosis, and management of VKC in Asia. The expert-led recommendations are summarized in this article and based on the currently available evidence alongside the clinical expertise of ophthalmologists from across Asia with specialism and interest in the ocular surface, VKC, and pediatric ophthalmology.

Discovery to Launch of Anti-allergy (Emadine; Patanol/Pataday/Pazeo) and Anti-glaucoma (Travatan; Simbrinza) Ocular Drugs, and Generation of Novel Pharmacological Tools Such as AL-8810

The eye and eyesight are exquistly designed and are precious, and yet we often take them for granted. Good vision is critical for our long-term survival and for humanity's enduring progress. Unfortunately, since ocular diseases do not culminate in life-and-death scenarios, awareness of the plight of millions of people suffering from such eye ailments is not publicized as other diseases. However, losing eyesight or falling victim to visual impairment is a frightening outlook for most people. Glaucoma, a collection of chronic optic neuropathies, of which the most prevalent form, primary open-angle glaucoma (POAG), is the second leading cause of irreversible blindness. POAG currently afflicts >70 million people worldwide and is an insidious, progressive, silent thief of sight that is asymptomatic. On the other hand, allergic conjunctivitis (AC), and the associated rhinitis ("hay-fever"), frequently victimizes a huge number of people worldwide, especially during seasonal changes. While not life-threatening, sufferers of AC soon learn the value of drugs to treat their signs and symptoms of AC as they desire rapid relief to overcome the ocular itching/pain, redness, and tearing AC causes. Herein, I will describe the collective efforts of many researchers whose industrious, diligent, and dedicated team work resulted in the discovery, biochemical/pharmacological characterization, development and eventual launch of drugs to treat AC (e.g., olopatadine [Patanol/Pataday/Pazeo] and emedastine [Emedine]), and for treating ocular hypertension and POAG (e.g., travoprost [Travatan ] and Simbrinza). This represents a personal perspective.

An Update on the Therapeutic Approach to Vernal Keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is an inflammatory disease of the ocular surface. It commonly occurs in the first decade of life, has a wide geographical distribution, and usually occurs in warm, dry areas. The pathogenesis of VKC seems to have an immune, nervous, and endocrine basis. The most common eye symptoms are itching, discharge, tearing, eye irritation, redness of the eyes, and photophobia. Although VKC generally has a good prognosis, the lack of clarity regarding the origin of the disease makes treatment a challenge for pediatricians and ophthalmologists. The purpose of this review is to discuss the pathogenesis, clinical features, and diagnostic criteria in VKC, with a focus on its therapeutic management. The selection of a therapeutic scheme from the many available options is based on clinical features and the personal preferences of both physicians and patients. Due to the lack of uniform grading of disease severity, there is no worldwide consensus on first-line and second-line therapeutic approaches. The choice of treatment for long-term moderate to severe VKC includes topical cyclosporine or tacrolimus. Further data are needed to define the minimal effective concentration and the safety of these drugs in eye drops and to clarify the diagnosis of VKC in patients who require these drugs. Finally, while promising newly discovered drugs are expected to enter into clinical practice, further studies on their efficacy and safety are required.

Management of vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a relatively rare, chronic form of ocular allergy that can potentially cause severe visual complications. Affecting mainly children and young adults, it is an IgE- and T cell-mediated disease, leading to a chronic inflammation in which eosinophil, lymphocyte and structural cell activation are involved. Treatment of VKC requires a multiple approach that includes conservative measures and pharmacologic treatment. Patients and parents should be made aware of the long duration of disease, its chronic evolution and possible complications. Treatment should be based on the duration and frequency of symptoms and the severity of corneal involvement. Mast cell stabilizers and antihistamines have been proven to be effective for the treatment of mild to moderate forms of VKC. In the most severe cases, topical steroids can be used as rescue medication to reduce conjunctival and corneal inflammation. Immunomodulators that have been investigated for VKC treatment include topical ocular preparations of cyclosporine A and tacrolimus. Topical cyclosporine A has been proven to be effective in the long-term treatment of VKC, significantly improving signs and symptoms without significant side effects.

Ocular allergy in pediatric practice

Allergies occur frequently in all pediatric age groups, affecting up to 40% of children. Allergic conjunctivitis is the most common ocular allergy syndrome among children, with atopic keratoconjunctivitis and vernal keratoconjunctivitis comprising less common, but potentially more severe, forms of ocular allergy. In this article, we review the impact, diagnosis, potential complications, and treatment of these ocular allergic pediatric conditions. Early detection is necessary to prevent potentially serious consequences of pediatric ocular allergy. Involvement of pediatric ophthalmologists may be necessary to avoid preventable vision loss in severe cases.

Efficacy and response with olopatadine versus epinastine in ocular allergic symptoms: A post hoc analysis of data from a conjunctival allergen challenge study

OBJECTIVES

This post hoc analysis used data from a previous study to more precisely evaluate the efficacy of olopatadine hydrochloride and epinastine hydrochloride in alleviating various levels of severity of ocular itching and conjunctival redness and to determine whether there were any significant differences in the number of responders to treatment.

METHODS

The original study was a randomized, double-masked allergen challenge comparison assessment. Adult patients with allergic conjunctivitis were screened (visits 1 and 2); those who exhibited positive allergic reactions at both visits were randomized to 1 of 3 groups. olopatadine/epinastine, olopatadine/placebo, or epinastine/placebo. At visit 3, each eye was treated with study medication, and then challenged with allergen. Itching, redness, and chemosis assessments were recorded. For the present post hoc analysis, each eye in the olopatadine/epinastine group was separately classified at each time point, based on the pretreatment severity of their symptom (itching) and sign (conjunctival redness) scores, as moderate, moderate/severe, or severe. Data were analyzed to determine responders (eyes with itching and/or conjunctival redness scores of 0 [none]).

RESULTS

Of 96 patients screened, 66 were randomized to treatment (36 women, 30 men; mean age, 44.38 years [range, 20-71 years]). Olopatadine-treated eyes exhibited lower mean itching scores than epinastine-treated eyes in the moderate/severe and severe groups at all 3 time points (3, 5, and 7 minutes), with significance in the moderate/severe group at 5 minutes (P = 0.05) and in the severe group at 5 and 7 minutes (P = 0.017 and P = 0.02, respectively). Olopatadine-treated eyes had mean conjunctival redness scores similar to epinastine-treated eyes in all severity groups at all time points (10, 15, and 20 minutes) except in the severe group at 10 minutes (P = 0.03). On response analysis, for itching, the proportion of responders was significantly greater in the olopatadine group versus the epinastine group 7 minutes after challenge (27 [50.9%] vs 14 [26.4%]; P = 0.016). For conjunctival redness, the proportion of responders was significantly greater with olopatadine treatment versus epinastine treatment at 15 and 20 minutes after challenge (15 minutes, 12 [22.6%] vs 1 [1.9%] [P = 0.002]; 20 minutes, 10 [18.9%] vs 1 [1.9%] [P = 0.008]).

Pharmacology of ocular allergy

PURPOSE OF REVIEW

To evaluate the pharmacology of current drug development directed towards ocular allergy. Increased worldwide prevalence of ocular allergy has stimulated expansion of management strategies towards physiologic and immunologic drug targets.

RECENT FINDINGS

Present drug targets are located in the conjunctival mucosal surface at the initial site of allergen exposure. Pharmacologic intervention attends to early and late phase reactions. Targets generating a response include mast cells, IgE, released preformed mediator histamine, and newly formed mediators, such as prostaglandins, leukotrienes and cytokines. Methods to simulate allergy and measure efficacy of drugs are the conjunctival allergen challenge and the conjunctival provocation test. Pharmacologic outcome is measured via cytologic biomarkers and clinical signs/symptoms of redness, itching, lid swelling and chemosis. Endpoint instruments such as the Ocular Allergy Index and Eye Allergy Patient Impact Questionnaire have emerged from the field of pharmacoeconomics.

SUMMARY

Important pharmacologic properties of targets have been revealed. First, histamine is more specifically antagonized by second generation antihistamines. Second, newly formed mediators and downstream responders (prostaglandins, leukotrienes, interleukins, intercellular adhesion molecule 1, tumor necrosis factor, vascular cell adhesion molecule, eosinophils and neutrophils) are more selectively antagonized by dual/multiple-action agents.

Emerging drugs for ocular allergy

Ocular allergy is a common condition that usually affects the conjunctiva of the eye and is, therefore, often referred to as allergic conjunctivitis. The severity of the disease can range from mild itching and redness, as seen in seasonal allergic conjunctivitis, to the more severe, sight-threatening forms such as vernal and atopic keratoconjunctivitis. The central mechanism in the pathogenesis of these diseases is IgE-mediated mast cell degranulation and activation of T lymphocytes, eosinophils and conjunctival structural cells. The pharmacotherapy of allergic conjunctivitis consists of several classes of drugs: antihistamines, mast cell stabilisers, dual-acting agents and corticosteroids. None of the available drugs completely abolishes the development of ocular allergy. For this reason, new topical antiallergic/anti-inflammatory agents are currently and continually under clinical trials. This review provides a background to ocular allergic diseases, the medical need for therapy and current and potential new treatments.

Mast cell stabilization and anti-histamine effects of olopatadine ophthalmic solution: a review of pre-clinical and clinical research

BACKGROUND

Histamine receptor activation and degranulation of mast cells are the mechanisms by which the ocular itching, hyperemia, chemosis, eyelid swelling, and tearing of seasonal allergic conjunctivitis are induced. Some of the topical solutions available as anti-allergy therapies are intended to interfere with these mechanisms, and the body of research regarding the capabilities of these therapeutic molecules continues to expand.

OBJECTIVE

To review the currently available literature regarding one topical ophthalmic anti-allergy agent, olopatadine (Patanol), and its anti-histaminic and mast cell stabilizing actions, both in pre-clinical and clinical settings.

DESIGN AND METHODS

Relevant research of laboratory, animal model, and clinical trial studies performed using olopatadine was reviewed. MEDLINE literature searches were conducted and supplemented by additional reports which furthered relevant discussion or were necessary to verify the information resulting from original searches.

RESULTS

Olopatadine demonstrates unique properties both pre-clinically and clinically which differentiate it from other therapeutic molecules in its class of dual action mast cell stabilizer/anti-histamine. Its non-perturbation of cell membranes, human conjunctival mast cell stabilization in vivo and in vitro, and superior efficacy as compared to other topical anti-allergic medications including mast cell stabilizers, anti-histamines, and dual action agents, all contribute to olopatadine's profile.

CONCLUSIONS

Peer-reviewed literature suggests that olopatadine is clinically superior to the other anti-allergic molecules because of its strong anti-histaminic qualities and its unique ocular mast cell stabilizing properties.

Clinical efficacy of olopatadine vs epinastine ophthalmic solution in the conjunctival allergen challenge model

BACKGROUND

Olopatadine hydrochloride 0.1% ophthalmic solution (Patanol) and epinastine hydrochloride 0.05% ophthalmic solution (Elestat) are two topical antiallergic agents. Olopatadine is indicated for the treatment of the signs and symptoms of allergic conjunctivitis that include itching, redness, tearing, lid swelling, and chemosis. Epinastine is indicated for the prevention of itching associated with allergic conjunctivitis.

OBJECTIVE

This study compared the clinical efficacy of olopatadine and epinastine in the prevention of itching and conjunctival redness in the conjunctival allergen challenge (CAC) model.

RESEARCH DESIGN AND METHODS

This was a prospective, randomized, double-masked, contralaterally-controlled, single center allergen challenge study. Ninety-six subjects with a history of allergic conjunctivitis were screened, and the 66 who responded to conjunctival allergen challenge at visits 1 and 2 were randomized into 1 of 3 treatment groups at visit 3 to receive one drop of study medication in each eye: (1) olopatadine in one eye and epinastine in the fellow eye, (2) olopatadine in one eye and placebo in the fellow eye, and (3) epinastine in one eye and placebo in the fellow eye. Five minutes after study drop instillation, subjects were bilaterally challenged with the allergen concentration that had elicited a positive conjunctival allergic response at Visits 1 and 2. Subjective itching assessments were given at 3 min, 5 min, and 7 min post challenge. Objective redness and chemosis assessments were made at 10 min, 15 min, and 20 min post challenge. Paired sample two-tailed t-tests were performed on the mean scores at each time point to assess statistical significance in the differences between treatments. MAIN OUTCOME MEASURES;

RESULTS

Fifty-three subjects were randomized into the olopatadine/epinastine treatment group, the primary analysis group. Olopatadine treated eyes exhibited significantly lower mean itching and conjunctival redness scores than the contralateral epinastine treated eyes, -0.19 (p = 0.003) and -0.52 (p < 0.001), respectively. Olopatadine treated eyes also exhibited significantly less chemosis -0.24 (p < 0.001), ciliary redness -0.55 (p < 0.001), and episcleral redness -0.58 (p < 0.001) than epinastine treated eyes.

CONCLUSION

Olopatadine is significantly more effective than epinastine in controlling itching, redness and chemosis associated with allergic conjunctivitis in the CAC model.

Review of complementary and alternative medicine in treatment of ocular allergies

PURPOSE OF REVIEW

Ocular allergy is a common complaint of allergy sufferers, many of whom may choose to use complementary and alternative medicine in the treatment of these symptoms. In this review major complementary and alternative medicine modalities including herbal therapies, acupuncture, homeopathy, alternative immunotherapy and behavior modification are assessed for evidence of their effectiveness in the treatment of ocular allergy symptoms.

RECENT FINDINGS

Certain herbs including Euphrasia officinalis, Petasites hybridus and Argemone mexicana have been evaluated in control studies in the treatment of ocular allergy. Honey is no more effective than placebo in the treatment of ocular allergy. Acupuncture used regularly has demonstrated some positive trends in ocular allergy sufferers. Homeopathy has shown conflicting results in the treatment of ocular allergy, while alternative forms of immunotherapy have been shown to develop immunologic tolerogenic effects in the control of the condition.

SUMMARY

Several forms of complementary and alternative medicine have been studied for their effectiveness in treatment of ocular allergy symptoms. Further research is needed to assess mechanisms of action and to establish practice guidelines for the use of these modalities

Nadroparine inhibits the hypersensitivity response in the conjunctiva

This study sought to investigate the effects of nadroparine on an in vivo experimental model of type I hypersensitivity response in the rat conjunctiva. Following drug application onto the eye, either before or after challenge with the mast cell degranulator, basic polyamine compound 48/80, the conjunctival histamine content and the nitrite levels in the conjunctival lavage fluid were quantified fluorometrically and spectrophotometrically, respectively. Instillation into the eye of nadroparine inhibited the C48/80-induced decreases in conjunctival histamine and the delayed increases in nitrite levels, without influencing basal mediator levels. Protamine did not induce histamine release and only partially reversed the effects of nadroparine post-challenge, yet it had no effect on the protective action of the drug when administered prior to degranulation. The results showed that nadroparine was equally effective in attenuating the effects of compound 48/80 in the eye when administered topically either before or after challenge.

Ocular Allergic Disease: Mechanisms, Disease Sub-types, Treatment

Ocular allergy refers to a variety of hypersensitivity disorders that affect the lid, conjunctiva, and/or cornea. Its incidence is estimated at over 20% of the general population in the United States. This review will discuss the various forms of ocular allergy, their pathophysiology, clinical presentation, and treatment. New frontiers in mechanisms, therapy, and management in the office are emphasized throughout.

Ocular allergy: implications for the clinical immunologist

BACKGROUND

Allergic diseases of the eye are the most common conditions affecting the external ocular adnexa. The most common forms are primarily IgE-mediated and share features in common with other atopic conditions. Mast cell activation and release of mediators, particularly histamine, are central to the pathogenesis of seasonal and perennial allergic conjunctivitis. These conditions are self-limited without the occurrence of ocular surface damage. In contrast, vernal keratoconjunctivitis and atopic keratoconjunctivitis are complex diseases, involving both early- and late-phase allergic responses. They are characterized by severe chronic immune inflammation with T cell infiltration in the conjunctiva and may be sight-threatening.

OBJECTIVES

To provide a brief overview of the ocular allergic conditions and summarize the current knowledge of immunopathogenetic mechanisms involved in initiating and driving these conditions.

DATA SOURCES

English-language articles were sought from a MEDLINE search from 1995. This yielded a number of scientific and review papers exploring recent advances in the understanding of the pathogenesis of the ocular allergic conditions.

CONCLUSIONS

Recent advances in knowledge about the pathogenetic mechanisms involved in ocular allergy have led to a better understanding of treatment options and to the development of new treatment modalities, resulting in improved control of symptoms for patients.

Ophthalmic drug discovery

Millions of people suffer from a wide variety of ocular diseases, many of which lead to irreversible blindness. The leading causes of irreversible blindness in the elderly--age-related macular degeneration and glaucoma--will continue to effect more individuals as the worldwide population continues to age. Although there are therapies for treating glaucoma, as well as ongoing clinical trials of treatments for age-related macular degeneration, there still is a great need for more efficacious treatments that halt or even reverse ocular diseases. The eye has special attributes that allow local drug delivery and non-invasive clinical assessment of disease, but it is also a highly complex and unique organ, which makes understanding disease pathogenesis and ocular drug discovery challenging. As we learn more about the cellular mechanisms involved in age-related macular degeneration and glaucoma, potentially, new drug targets will emerge. This review provides insight into some of the new approaches to therapy.

Ketotifen fumarate and olopatadine hydrochloride in the treatment of allergic conjunctivitis: a real-world comparison of efficacy and ocular comfort

This 3-week prospective, randomized, double-masked, parallel-group study compared ketotifen fumarate 0.025% ophthalmic solution and olopatadine hydrochloride 0.1% ophthalmic solution in 66 patients with seasonal allergic conjunctivitis. The drugs were instilled twice daily. Signs and symptoms were assessed on days 5 (visit 2) and 21 (visit 3). Other efficacy variables were the responder rate (patients with excellent or good global efficacy on days 5 and 21) and patient and investigator ratings of global efficacy. Comfort was evaluated immediately after instillation of the first drop and at each follow-up visit. The frequency of adverse events was the safety assessment. The responder rate was higher with ketotifen than with olopatadine on day 5 (72% vs 54% for patient assessment, 88% vs 55% for investigator assessment) and day 21 (91% vs 55%, 94% vs 42%). Global efficacy ratings were higher with ketotifen, and severity scores for hyperemia and itching were significantly lower. Both drugs elicited comparable comfort ratings. The most common adverse events were burning/stinging and headache.

Ocular allergy guidelines: a practical treatment algorithm

The treatment of ocular allergy requires a better understanding of the spectrum of clinical disorders involving various components of the immune system, and of interactions at the conjunctival surface. The immune response focuses primarily on the different levels of activity of Th2 lymphocytes and various other immune cells associated with allergic disorders, including mast cells, eosinophils, fibroblasts, and epithelial and endothelial cells. Ocular allergic disorders include seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC), giant papillary conjunctivitis (GPC) and atopic keratoconjunctivitis (AKC), which, through immunopathological and molecular immunological techniques, can all be better appreciated as being part of a larger spectrum of an atopic disease state. In SAC, pathological changes, such as increased mast-cell activation, the presence of migratory inflammatory cells, and early signs of cellular activation at the molecular level, are minimal. In PAC, these changes are more pronounced in line with the increased duration of allergenic stimulation. In more chronic forms of allergic conjunctivitis, such as VKC in children and AKC in adults, the following changes are evident: a persistent state of mast cell, eosinophil and lymphocyte activation; noted switching from connective-tissue to mucosal-type mast cells; increased involvement of corneal pathology; and follicular development and fibrosis. The treatment of acute and more chronic forms of allergic conjunctivitis has focused in the past on symptomatic relief of symptoms, but with a better understanding of the mechanisms involved we can now provide interventional therapeutic strategies and symptomatic relief. Our advances in the basic understanding of these conditions are providing the foundation for guidelines that improve the ocular health of patients with ocular allergies.

Changes in tear function and the ocular surface after topical olopatadine treatment for allergic conjunctivitis: an open-label study

BACKGROUND

Olopatadine hydrochloride 0.1% eye drops represent a new class of anti-allergic agent with combined antihistaminic and mast cell-stabilizing properties.

OBJECTIVE

The purpose of this study was to describe alterations in tear function and the ocular surface in patients with allergic conjunctivitis and to analyze the effect of topical olopatadine treatment on corneal sensitivity, tear function, and impression cytology variables.

METHODS

This was a single-center, 3-visit, prospective, open-label study conducted in patients with allergic conjunctivitis. Patients received 1 drop of topical olopatadine hydrochloride 0.1% BID for 3 weeks. At each visit, patients and healthy control subjects underwent routine ophthalmic examinations and measurements of corneal sensitivity and tear function (Schirmer test of tear quantity, tear film break-up time [BUT], fluorescein staining of the cornea). All control subjects and a subgroup of patients also underwent conjunctival impression cytology for assessment of squamous metaplasia and goblet cell density. The outcomes of interest were changes in corneal sensitivity, tear function, and impression cytology variables after 3 weeks of treatment with olopatadine eye drops, both in patients with allergic conjunctivitis and between patients and controls.

RESULTS

At enrollment, the study included 46 eyes of 23 patients (9 men, 14 women; age range, 20-42 years) with allergic conjunctivitis; results were calculated based on the 21 patients who completed the study. The control group consisted of 70 eyes of 35 healthy subjects (13 men, 22 women; age range, 22-39 years). Before treatment, 64.3% of the eyes of patients with allergic conjunctivitis had a fluorescein staining score of >1 point, whereas after treatment, 14.3% had a score of >1 point (P < 0.001). Patients' mean (+/- SD) corneal sensitivity improved to 55.0 +/- 2.5 mm from the pretreatment value of 42.5 +/- 2.5 mm (P < 0.001). Mean BUT values before and after treatment were 8.1 +/- 3.5 and 14.0 +/- 7.0 seconds, respectively (P < 0.001). Before treatment, patients' mean squamous metaplasia grade was 2.5 +/- 0.5; at the end of treatment, it had decreased to 1.0 +/- 0.5 (P < 0.001). The mean pretreatment goblet cell density of 545 +/- 85 cells/mm2 improved to 1,090 +/- 100 cells/mm2 after treatment (P < 0.001).

CONCLUSION

In the patient population studied, the disorder of tear function, squamous metaplasia, and loss of ocular surface goblet cells associated with allergic conjunctivitis improved with topical olopatadine treatment.

Comparison of the clinical efficacy and tolerability of olopatadine hydrochloride 0.1% ophthalmic solution and loteprednol etabonate 0.2% ophthalmic suspension in the conjunctival allergen challenge model

BACKGROUND

Olopatadine hydrochloride 0.1% ophthalmic solution and loteprednol etabonate 0.2% ophthalmic suspension are topical antiallergic agents indicated for treatment of the signs and symptoms of allergic conjunctivitis and seasonal allergic conjunctivitis (SAC), respectively.

OBJECTIVE

The purpose of this study was to compare the efficacy and tolerability of olopatadine, loteprednol, and placebo in inhibiting the early-phase allergic reaction (within 30 minutes) after conjunctival allergen challenge (CAC).

METHODS

This was a single-center, randomized, double-masked, parallel-controlled CAC study. It consisted of 3 visits, with CAC performed at visit 1, confirmation and randomization at visit 2, and evaluation of the treatments at visit 3. Subjects with a history of allergic conjunctivitis were randomized to receive olopatadine, loteprednol, or placebo in a 2:2:1 ratio. Because loteprednol requires a loading period to achieve maximum efficacy, subjects assigned to this treatment received loteprednol QID bilaterally for a 14-day period; the olopatadine and placebo groups received placebo QID bilaterally during this period. At the evaluation visit, subjects received 1 drop of the assigned treatment in each eye. Fifteen minutes later, they were challenged with allergen. Subjects evaluated itching at 3, 5, and 10 minutes after challenge using a standardized 5-point scale; the investigator evaluated redness at 10, 15, and 20 minutes after challenge. Intraocular pressure (IOP) was measured at baseline and after the 14-day loading period. Nonparametric analyses were performed on the change from visit 2 to visit 3 in mean itching and redness scores for each time point, and on the change in mean IOP from visit 1 to visit 3.

RESULTS

Fifty subjects (86% white; 42% male, 58% female; age range, 21-71 years) were enrolled and completed the study (20 olopatadine, 20 loteprednol, 10 placebo). The allergens to which subjects reacted were ragweed pollen (40%), cat hair or dander (30%), grass pollen (24%), and tree pollen (6%). The difference in inhibition of itching and redness was clinically significant (> or =1 unit difference) and statistically significant (P < 0.05) in favor of olopatadine compared with loteprednol at all 3 time points. The loteprednol group had a statistically significant increase in IOP after 2 weeks of treatment (P < 0.001).

CONCLUSION

In the population studied, olopatadine was more efficacious than loteprednol in reducing the acute signs and symptoms of SAC during the early phase of the ocular allergic reaction and appeared to be better tolerated.

Evaluation of the efficacy of olopatadine hydrochloride 0.1% ophthalmic solution and azelastine hydrochloride 0.05% ophthalmic solution in the conjunctival allergen challenge model

BACKGROUND

Olopatadine hydrochloride 0.1% ophthalmic solution and azelastine hydrochlofide 0.05% ophthalmic solution are 2 topical antiallergic agents indicated for the treatment of itching of the eye associated with allergic conjunctivitis. Olopatadine has recently received US Food and Drug Administration (FDA) approval for an expanded indication for the treatment of signs and symptoms of allergic conjunctivitis, including itching, tearing, eyelid swelling, redness, and chemosis.

OBJECTIVE

The purpose of this study was to compare the efficacy of olopatadine hydrochloride versus azelastine hydrochloride and placebo (artificial tears) in the conjunctival allergen challenge (CAC) model.

METHODS

This was a prospective, randomized, double-masked, contralaterally controlled, multicenter, allergen-challenge study. Itching was chosen as the primary efficacy variable since it is the only FDA-approved indication these 2 agents have in common. Subjects with a history of allergic conjunctivitis who responded to the CAC at screening visits 1 and 2 were randomized to 1 of 3 treatment groups: olopatadine in 1 eye and azelastine in the other eye; olopatadine in 1 eye and placebo in the other eye; or azelastine in 1 eye and placebo in the other eye. At the assessment visit (visit 3), subjects received masked study medication according to the randomization scheme. After 5 minutes, subjects were bilaterally challenged with the allergen concentration that had elicited a positive conjunctival allergic response at visits 1 and 2. Immediately after challenge, subjects gave itching assessments (scale, 0 = no itching to 4 = severe itching) every 30 seconds for a total period of 20 minutes. Mean itching scores for all eyes were compared by treatment. Mean itching scores at each time point were compared between treatments using 2 sample t tests.

RESULTS

Of the 180 subjects screened, 111 responded to the CAC at visits 1 and 2 and completed the study; 65% (72/111) of patients were female, 87% (97/111) were white, and 49% (54/111) had brown irides. The mean age was approximately 40 years. Seventy-three eyes were treated with olopatadine, 75 with azelastine, and 74 with placebo. A single dose of 1 of the 3 study medications per eye was well tolerated by all subjects. Both treatments were significantly more effective than placebo at reducing itching postchallenge. Olopatadine was significantly more effective than azelastine in reducing itching at 3.5 minutes through 20 minutes postchallenge (average mean unit difference of -0.31; P < 0.05) in the CAC model.

CONCLUSION

In this population, olopatadine was significantly more effective than azelastine in the management of itching associated with allergic conjunctivitis in the CAC model.

Comparison of the clinical efficacy and comfort of olopatadine hydrochloride 0.1% ophthalmic solution and nedocromil sodium 2% ophthalmic solution in the human conjunctival allergen challenge model

BACKGROUND

Mast cell stabilizers, such as the ocular antiallergic agent nedocromil sodium 2% ophthalmic solution, are not rapid acting and often require a loading period of > or =2 weeks for maximal efficacy. Olopatadine hydrochloride 0.1% ophthalmic solution is a member of a new class of topical antiallergic agents that have combined antihistaminic and mast cell-stabilizing properties.

OBJECTIVE

The purpose of this study was to compare the clinical efficacy and comfort of olopatadine with those of nedocromil in the conjunctival allergen challenge model.

METHODS

This was a single-center, 3-visit, randomized, double-masked, contralaterally controlled study. Seventy-five subjects with a history of allergic conjunctivitis were screened, and the 52 who responded to conjunctival allergen challenge at visits I and 2 were randomized by eye to receive olopatadine, nedocromil, or placebo (a "natural tears" lubricant eye drop). Because nedocromil may require a 2-week loading period for maximal efficacy, the eyes assigned to that agent received nedocromil for 14 days (between visits 2 and 3), whereas the eyes assigned to olopatadine or placebo received placebo during this period. Throughout the loading phase, subjects instilled 1 drop of the assigned masked medication in each eye twice daily. At the assessment visit (visit 3), subjects received I drop of masked olopatadine, nedocromil, or placebo in each eye and were asked to rate the comfort of each drop on a scale from 0 to 8. Fifteen minutes after instillation of medication, subjects were challenged with the allergen concentration that had elicited a positive conjunctival allergic response at the previous visits. Subjects then scored their itching on a scale from 0 to 4 at 3, 5, and 10 minutes after challenge. Mean itching scores for all eyes were compared by treatment. Paired t tests were performed on the mean itching and ocular comfort scores at each time point. At the end of the study, subjects were asked which treatment they preferred in terms of comfort and efficacy.

RESULTS

Forty-nine subjects completed the study. Forty eyes received olopatadine, 36 received nedocromil, and 22 received placebo. Olopatadine was clinically and statistically superior to nedocromil at reducing itching in the conjunctival allergen challenge model (mean unit difference: -1.60 at 3 minutes, -1.68 at 5 minutes, -1.19 at 10 minutes; P < 0.001). One drop of olopatadine was more efficacious than 29 drops of nedocromil. Olopatadine-treated eyes were rated as being significantly more comfortable than nedocromil-treated eyes (0.73 vs 1.55; P = 0.034). Of the 14 subjects treated with olopatadine and nedocromil who stated a preference, 10 (71%) were more satisfied with olopatadine than with nedocromil.

CONCLUSION

In the conjunctival allergen challenge model, olopatadine was more efficacious and comfortable than nedocromil in reducing the itching associated with allergic conjunctivitis.

A comparison of the relative efficacy and clinical performance of olopatadine hydrochloride 0.1% ophthalmic solution and ketotifen fumarate 0.025% ophthalmic solution in the conjunctival antigen challenge model

OBJECTIVE

The purpose of this study was to compare the relative efficacy and clinical performance of olopatadine hydrochloride 0.1% ophthalmic solution and ketotifen fumarate 0.025% ophthalmic solution in the conjunctival antigen challenge model.

METHODS

This was a prospective, randomized, double-masked, contralaterally controlled, single-center, antigen challenge study. Of the 53 subjects screened, 32 were enrolled and completed the study. The study comprised 3 visits. Primary efficacy variables were ocular itching (assessed at visits 2 and 3) and subject satisfaction (assessed at visit 3). Tolerability variables were slit-lamp findings (all visits), visual acuity (all visits), ocular comfort after drug instillation (visit 3), and adverse events (visits 2 and 3). At visit 1, the antigen concentration that elicited a positive ocular allergic response was determined, and this concentration was confirmed at visit 2. Subjects graded itching on a 5-point scale at 3, 5, and 10 minutes postchallenge. The scores from this visit were used as baseline scores and compared with scores from visit 3 to determine drug efficacy. At visit 3, subjects were randomly assigned to 2 treatment groups. Group A received 1 drop of olopatadine in the right eye and I drop of ketotifen in the left eye. Group B received 1 drop of olopatadine in the left eye and 1 drop of ketotifen in the right eye. Following drug instillation, the subjects assessed the comfort level in each eye. Twelve hours after instillation, subjects were challenged with the antigen concentration that elicited a positive response at the previous visits. Itching was subjectively graded at 3, 5, and 10 minutes postchallenge. Subjects were asked to choose which therapy they were more satisfied with.

RESULTS

Twelve hours after administration, efficacy scores for olopatadine were significantly higher than those for ketotifen at 3 and 5 minutes postchallenge (1.84 and 1.75 vs 1.25 and 1.34; P < 0.05). Olopatadine-treated eyes were rated significantly more comfortable than those treated with ketotifen immediately after drug instillation (1.25 vs 2.09; P < 0.05) and 12 hours later, as measured by patient ratings of ocular comfort. Of the 22 subjects who had a preference, 16 (73%) were more satisfied with olopatadine than with ketotifen.

CONCLUSIONS

Olopatadine is more effective than ketotifen in reducing the itching associated with allergic conjunctivitis in the antigen challenge model. Olopatadine caused less ocular discomfort than ketotifen and was preferred by approximately 3 times as many patients as was ketotifen.