A double blind placebo controlled group comparative study of ophthalmic sodium cromoglycate and nedocromil sodium in the treatment of vernal keratoconjunctivitis

Management of vernal keratoconjunctivitis: Navigating a changing treatment landscape

Vernal keratoconjunctivitis (VKC) is a chronic, progressive, and potentially sight-threatening form of ocular inflammatory disease that primarily affects children and young adults. Prevalence varies by region, ranging from <2 per 10,000 in the United States to as high as 1,100 per 10,000 in parts of Africa. The rarity of VKC in developed countries can make differential diagnosis challenging, and treatment is often delayed until the disease is advanced, and symptoms are significantly impacting patients' quality of life. Although once viewed primarily as an immunoglobulin E-mediated condition, approximately 50% of patients with VKC do not exhibit allergic sensitization. It is now recognized that the immunopathology of VKC involves multiple inflammatory pathways that lead to the signs, symptoms, and conjunctival eosinophilic and fibroproliferative lesions that are a hallmark of the disease. We examine the evolution of our understanding of the immunopathology of VKC, the expanding VKC treatment armamentarium, the clinical implications of emerging treatment approaches, and future directions for VKC research and practice.

Comparative efficacy of medical treatments for vernal keratoconjunctivitis in children and young adults: a systematic review with network meta-analyses

PURPOSE

To systematically review the literature on the treatment of vernal keratoconjunctivitis (VKC) in children and young adults and conduct comparative efficacy analysis on clinical signs and symptoms using network meta-analyses.

METHODS

We systematically searched the databases PubMed/MEDLINE, EMBASE, Cochrane Central and Web of Science on 21 October 2019 for randomized controlled trials (RCT). Studies considered had patients with VKC < 20 years of age randomized into either intervention (any medical intervention) or comparator (active treatment, placebo treatment or non-treatment control), where pre-defined outcomes (data from ≥2 weeks and as close as possible to 2 months) of symptoms (itching, tearing, photophobia and foreign body sensation) and signs (hyperaemia, punctate keratitis, Horner-Trantas dots and macropapillae) were reported. Risk of bias within studies was evaluated using the Cochrane risk of bias tool. Comparisons were made using network meta-analyses.

RESULTS

We identified 39 studies with data on 2046 individuals. Twenty-three studies were eligible for quantitative analyses. None were systemic therapy. Temporal trend analysis showed that an initial focus on topical mast cell stabilizers turned to a focus on calcineurin inhibitors and a more diverse variety of pharmacological strategies. Studies varied in population, treatment duration and quality. The quantitative analysis revealed that efficacy of different therapies differed substantially across important clinical signs and symptoms, but there was a general trend of superior efficacy when using topical corticosteroids with stronger efficacy of the more potent corticosteroids.

CONCLUSION

We provide an overview of RCTs comparing the efficacy of treatments for VKC in children and young adults, which we find differs across symptoms and signs. Overall, we saw a general trend of superior efficacy with topical corticosteroids. However, our findings highlight the need for better studies, consensus on core outcomes and potential for individualized therapy.

Efficacy of medical treatments for vernal keratoconjunctivitis: A systematic review and meta-analysis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a severe type of allergic conjunctivitis for which treatment strategies are still under debate.

OBJECTIVES

This study sought to conduct a systematic review and meta-analysis to evaluate the efficacy of medical treatments for VKC.

METHODS

The PubMed, Cochrane Library, Embase, and ScienceDirect databases were searched to assess the efficacy of treatments for VKC. Random-effect meta-analyses on changes in clinical scores of symptoms and signs between baseline and after treatment, stratified on treatment classes, were computed. Meta-regressions were searched for potential influencing parameters.

RESULTS

Included were 45 studies (27 randomized controlled trials and 18 prospective cohort studies), 1749 patients (78% were men; mean age, 11.2 years), and 12 different treatment classes. Mast cell stabilizers (MCSs; usually considered as first-line therapy), cyclosporine, and tacrolimus were the most studied drugs (in three-quarters of studies). Overall, all clinical scores improved. Total symptom and sign score decreased for MCSs (effect size, -3.19; 95% CI, -4.26 to -2.13), cyclosporine (effect size, -2.06; 95% CI, -2.72 to -1.40), and tacrolimus (effect size, -2.39; 95% CI, -3.36 to -1.43). No significant differences were shown depending on treatment classes, concentration, age, sex, baseline activity scores, and atopy. Sensitivity analyses demonstrated similar results.

CONCLUSIONS

This study confirms the efficacy of MCSs in the treatment of VKC. Efficacy of cyclosporine and tacrolimus did not differ, suggesting that tacrolimus is a good alternative to cyclosporine for severe cases of VKC. Further studies are needed to compare other drugs and their precise place in treatment strategy.

Ocular itch associated with allergic conjunctivitis: latest evidence and clinical management

Allergic conjunctivitis is one of the most common allergic conditions worldwide. Its incidence is increasing due to changing climate, pollution, increased pollen loads, and the subject's heightened immunological sensitivity in response to these environmental changes. The pathophysiology predominantly involves immunoglobulin E-related mast-cell activation, with release of histamine and other mediators contributing to the propagation of the response by calling in other immune cells and further inflammation. This article presents the evolution of ocular allergy treatments, from vasoconstrictors, to antihistamines and mast-cell stabilizers, to the dual-acting agents, as well as corticosteroid and immunomodulatory options. Future targets for allergy treatment are also discussed.

Vernal keratoconjunctivitis: a severe allergic eye disease with remodeling changes

Vernal keratoconjunctivitis (VKC) is an unusually severe sight-threatening allergic eye disease, occurring mainly in children. Conventional therapy for allergic conjunctivitis is generally not adequate for VKC. Pediatricians and allergists are often not familiar with the severe clinical symptoms and signs of VKC. As untreated VKC can lead to permanent visual loss, pediatric allergists should be aware of the management and therapeutic options for this disease to allow patients to enter clinical remission with the least side effects and sequelae. Children with VKC present with severe ocular symptoms, that is, severe eye itching and irritation, constant tearing, red eye, eye discharge, and photophobia. On examination, giant papillae are frequently observed on the upper tarsal conjunctiva (cobblestoning appearance), with some developing gelatinous infiltrations around the limbus surrounding the cornea (Horner-Trantas dot). Conjunctival injections are mostly severe with thick mucus ropy discharge. Eosinophils are the predominant cells found in the tears and eye discharge. Common therapies include topical antihistamines and dual-acting agents, such as lodoxamide and olopatadine. These are infrequently sufficient and topical corticosteroids are often required for the treatment of flare ups. Ocular surface remodeling leads to severe suffering and complications, such as corneal ulcers/scars. Other complications include side effects from chronic topical steroids use, such as increased intraocular pressure, glaucoma, cataract and infections. Alternative therapies for VKC include immunomodulators, such as cyclosporine A and tacrolimus. Surgery is reserved for those with complications and should be handled by ophthalmologists with special expertise. Newer research on the pathogenesis of VKC is reviewed in this article. Vernal keratoconjunctivitis is a very important allergic eye disease in children. Complications and remodeling changes are unique and can lead to blindness. Understanding of pathogenesis of VKC may lead to better therapy for these unfortunate patients.

Comparative study of the ocular efficacy and safety of diclofenac sodium (0.1%) ophthalmic solution with that of ketorolac tromethamine (0.5%) ophthalmic solution in patients with acute seasonal allergic conjunctivitis

Background:

Seasonal allergic conjunctivitis (SAC) is the most common and most prevalent of allergic disorders which afflict the ocular surface. Of the several treatments available, ophthalmic non-steroidal anti-inflammatory drugs, are generally very safe and tolerable.

Aim:

The aim of this study is to compare the ocular efficacy and safety of diclofenac sodium (0.1%) ophthalmic solution with that of ketorolac tromethamine (0.5%) ophthalmic solution in patients with acute SAC.

Materials and Methods:

Sixty patients with signs and symptoms of SAC were evaluated in an open, randomized, parallel group study. The principle symptoms (ocular itching, burning, discharge, photophobia) and signs (ocular inflammation, lid edema, chemosis, conjunctival mucous, keratitis) were evaluated.

Study Design:

Patients were randomized into two groups of 30 each. Patients in group A received one drop of diclofenac sodium 0.1% and patients in group B received ketorolac tromethamine 0.5% in both the eyes four times a day for fourteen days. Evaluations were performed at day 0, 3, 7 and 14 of the therapy. At each visit, the signs and symptoms were rated using a scale from 0-3 (mild-1, moderate-2 and severe-3).

Results:

Significant clinical and statistical reductions in signs and symptoms from baseline were observed in both groups. Diclofenac sodium 0.1% was superior to ketorolac tromethamine 0.5% in reducing ocular itching (P < 0.05) and ocular inflammation (P < 0.05), at the final examination.

Conclusion:

Diclofenac sodium showed statistically significant better results at day 3 and 7 compared to ketorolac.

Clinical review: topical ophthalmic use of cyclosporin A

Cyclosporine A (CsA) is an immunomodulatory agent that primarily inhibits the proliferation and action of T cells. Systemic CsA has been used successfully in solid organ transplantation and noninfectious uveitis. Topical CsA with various formulations has been used in the field of ocular surface diseases since early 1980s. An ophthalmic emulsion 0.05% (Restasis, Allergan, Irvine, CA), was approved by the United States Food and Drug Administration in 2003 to treat dry eye syndrome. This article aims to evaluate the peer-reviewed published scientific literature and to define well-established uses of CsA eyedrops in the field of ocular surface diseases.

Vernal conjunctivitis

Vernal conjunctivitis is a bilateral, seasonal, external ocular inflammatory disease of unknown cause. Afflicted patients experience intense itching, tearing, photophobia, and mucous discharge, and usually demonstrate large cobblestone papillae on their superior tarsal conjunctiva and limbal conjunctiva. It primarily affects children, may be related to atopy, and has environmental and racial predilections. Although usually self-limited, vernal conjunctivitis can result in potentially blinding corneal complications. Treatment of chronic forms of ocular allergies may necessitate collaborative efforts between the ophthalmologist and the allergist or immunologist.

Treating the ocular component of allergic rhinoconjunctivitis and related eye disorders

CONTEXT

Allergy symptoms that affect the eyes are common in adults and children worldwide, and are often associated with nasal allergy symptoms, prompting the term 'rhinoconjunctivitis' to describe the condition. However, this condition has not always been recognized, and earlier literature reported allergic conjunctivitis only within a subset of nasal allergy patients.

EVIDENCE ACQUISITION

To assess the current state of ocular allergy epidemiology, pathophysiology, and currently available treatment options, we performed a MEDLINE search for articles regarding ocular allergy, rhinoconjunctivitis, vernal keratoconjunctivitis (VKC), atopic keratoconjunctivitis (AKC), and giant papillary conjunctivitis (GPC).

EVIDENCE SYNTHESIS

The more severe forms of ocular allergy are not only distressing, but can also threaten a patient's vision. Each type of ocular allergy is associated with ocular redness, itching, and tearing; however, AKC and VKC can threaten the cornea, and research has revealed that involvement of different immune cell populations (mast cells, eosinophils, and lymphocytes) may cause these more severe symptoms. A variety of treatment options exist to control ocular allergy symptoms. Nonpharmacologic options include allergen avoidance and lubrication with saline, and if these fail to be sufficiently effective, symptom relief may be provided by medicinal agents that are either applied topically to the eye or taken orally. Recent evidence suggests that nasal allergy treatments applied topically to the nose may also positively affect ocular allergy symptoms, which raises the interesting possibility that a parasympathetic nasal-ocular neural reflex pathway may be involved in the stimulation of allergic responses in the eye.

CONCLUSIONS

Ocular allergy is underdiagnosed and has a significant impact on the life of the patient. It is vital to reach a better understanding of ocular allergic mechanisms and inflammation, which may lead to improved treatment.

Systematic review and meta-analysis of randomised clinical trials on topical treatments for vernal keratoconjunctivitis

AIMS

The aim of this study was to assess the efficacy of currently available topical drugs for vernal keratoconjunctivitis (VKC) through a meta-analysis of randomised clinical trials (RCTs).

METHODS

Twenty-seven RCTs (n = 2184 eyes) that had evaluated the efficacy of topical drugs for the treatment of VKC were selected according to the set criteria; 10 of these trials were suitable for statistical analysis and were enrolled in the meta-analysis. Articles published up to December 2005 were identified from the following

DATA SOURCES

Medline, Embase, Lilacs, the Cochrane Controlled Trials Register, and references from relevant articles. Articles in any language published with an English abstract, were screened, and those selected for inclusion were written in English, French, German, Italian, Portuguese or Spanish. The quality of the trials was assessed by the Delphi list. Statistical analysis was performed using STATA software.

RESULTS

A significant improvement in all signs and symptoms, except photophobia, was observed after topical treatment for active VKC, independent of the type of treatment. Comparison of the efficacy of different drugs was not possible due to a lack of standardised criteria among studies.

CONCLUSION

The currently available topical drugs are effective in treating acute phases of VKC. However, there is a lack of evidence to support the recommendation of one specific type of medication for treating this disorder. There is a need for standard criteria to assess diagnosis and therapy based on severity. There is also a need for RCTs assessing long-term effects of single drugs to control the disease and to prevent complications.

Topical Bromfenac Sodium for Long-Term Management of Vernal Keratoconjunctivitis

BACKGROUND/AIMS

We evaluated the efficacy and safety of long-term management of patients with vernal keratoconjunctivitis (VKC) with bromfenac sodium eye drops in combination with corticosteroids and anti-allergic eye drops.

METHODS

Twenty-two patients with VKC were randomly assigned to receive two test eye drops, either bromfenac sodium 0.1% (group A) or placebo eye drops (normal saline; group B) for a mean observation period of 20.9 months. Topical corticosteroids and mast cell stabilizers were continued during the observation period.

RESULTS

The mean 2-year recurrence rate was 90.9% in group A and 11.3% in group B, with a significant difference. No serious side effect was observed in group A.

CONCLUSION

These results suggest that bromfenac sodium eye drops can be used as baseline local treatment in patients with VKC.

Topical ciclosporin in the treatment of ocular surface disorders

Mounting evidence suggests that inflammation is the key factor in the pathogenesis of various ocular surface diseases, with a complex interplay of genetic, environmental, and psychosocial factors. Management of these conditions is often challenging. Topical corticosteroids, with their associated side effects, are the mainstay of current treatments for patients with vision threatening disease. Ciclosporin A is an immunomodulator that specifically inhibits T lymphocyte proliferation. Recently, a topical ciclosporin preparation was approved by the US Food and Drug Administration and became available for use in ophthalmology. Given the increasing use of ciclosporin eye drops, the goal of this article is to provide the reader with an overview of the well established uses of ciclosporin and to help refine the questions that should be addressed by future investigations.

A combined analysis of two studies assessing the ocular comfort of antiallergy ophthalmic agents

BACKGROUND

Many topical agents with similar efficacies are available for the treatment of ocular allergies. In addition to efficacy, comfort is an important criterion because it affects overall patient satisfaction, compliance, and in turn efficacy.

OBJECTIVE

The goal of this study was to compare the comfort profiles of permirolast, ketorolac, cromolyn, and nedocromil ophthalmic solutions using combined results from 2 separate clinical trials.

METHODS

Two clinical trials were conducted. Adults with asymptomatic eyes were included in the first study. In this single-center, 7-day, prospective, double-blind, single-dose, crossover, parallel-group study, subjects were randomized to be bilaterally dosed with pemirolast, cromolyn, or ketorolac at each of 3 visits. Study 2 was a single-center, 1-day, prospective, randomized, double-blind, single-dose, contralateral, active-control study in which subjects received pemirolast in 1 eye and nedocromil in the contralateral eye. In both studies, subjects completed a pre- and postinstillation ocular comfort questionnaire: the primary variable was overall ocular discomfort, measured on a 4-point scale original to these studies (0 = absent, 1 = mild, 2 = moderate, 3 = severe). Half-increments were permitted. Secondary variables included burning/stinging, foreign-body sensation, tearing, and photophobia.

RESULTS

Forty-five subjects (29 women, 16 men; mean [SD] age, 35.9 [12.6] years) were enrolled in study 1; 48 subjects (30 women, 18 men; mean [SD] age, 33.6 [10.2] years) were enrolled in study 2. In study 1, overall discomfort was significantly lower with pemirolast than with cromolyn (P = 0.001) or ketorolac (P < 0.001). In terms of overall discomfort, the number of subjects with a clinically significant increase (>/=1 unit) in score was significantly lower with pemirolast compared with ketorolac (P = 0.021). Burning/stinging and tearing were also significantly lower with pemirolast than with cromolyn (P < 0.001 and P = 0.014, respectively). Mean changes in score compared with preinstillation were consistently lower with pemirolast than with cromolyn for both burning/stinging (P < 0.001) and tearing (P = 0.014). In study 2, overall discomfort was significantly lower with pemirolast than with nedocromil (P < 0.001). The number of subjects with a clinically significant increase in overall discomfort score was significantly lower with pemirolast than with nedocromil (P = 0.007). No changes in ocular tolerability parameters were reported in either study.

CONCLUSION

In these single-dose studies, pemirolast was found to be significantly more comfortable than cromolyn, ketorolac, or nedocromil.

Two mast cell stabilizers, pemirolast potassium 0.1% and nedocromil sodium 2%, in the treatment of seasonal allergic conjunctivitis: a comparative study

This randomized, double-masked, active-control, parallel-group trial compared the mast cell stabilizers pemirolast potassium 0.1% and nedocromil sodium 2% in the treatment of seasonal allergic conjunctivitis. Pemirolast is currently indicated for four-times-daily administration, nedocromil, for twice-daily dosing. Both ophthalmic solutions were instilled bilaterally twice a day for 8 weeks. The study involved four office visits and two telephone contacts. Participants evaluated their symptoms daily in take-home diaries (itching was the primary efficacy variable) and completed questionnaires to assess comfort. Of a total enrollment of 80, 78 patients completed the study. No significant differences were found between pemirolast and nedocromil on any signs or symptoms of allergic conjunctivitis (redness, chemosis, itching, eyelid swelling). At each visit, pemirolast was rated significantly more comfortable than nedocromil. A significantly higher percentage of the pemirolast group experienced no signs or symptoms at work or school (58% vs 28%; P = .005). The number of adverse events did not differ significantly between groups. Twice-daily administration of pemirolast potassium was as efficacious and safe as twice-daily nedocromil sodium in the 8-week treatment of ragweed allergic conjunctivitis and was superior to nedocromil in comfort. Increased comfort with pemirolast may increase patient satisfaction and compliance with therapy.

A comparison of the efficacy and tolerability of olopatadine hydrochloride 0.1% ophthalmic solution and cromolyn sodium 2% ophthalmic solution in seasonal allergic conjunctivitis

BACKGROUND

Treatments for allergic conjunctivitis have various mechanisms of action. Cromolyn sodium stabilizes conjunctival mast cells by preventing calcium influx across the cell membrane, whereas olopatadine hydrochloride is both an antihistamine and a mast cell stabilizer.

OBJECTIVE

This study compared the efficacy and tolerability of olopatadine and cromolyn in controlling the ocular signs and symptoms of seasonal allergic conjunctivitis.

METHODS

This was a multicenter, randomized, double-masked, parallel-group trial. One group instilled olopatadine 0.1% ophthalmic solution and placebo BID, and the other instilled cromolyn 2% ophthalmic solution QID, both for 6 weeks. The formulation of cromolyn used in this study is currently available only in Europe and Australia.

RESULTS

The intent-to-treat efficacy and safety analyses included 185 patients, 91 in the olopatadine group and 94 in the cromolyn group. At 30 minutes after the first instillation, respective decreases of approximately 30% and approximately 20% were reported in self-rated ocular itching and redness with both treatments; by 4 hours, itching had decreased by approximately 38% in both groups. Differences between treatments were not statistically significant. At 4 hours, redness had decreased by approximately 38% and approximately 26% in the respective treatment groups. By day 42, both treatments had produced significant reductions from baseline in ocular signs and symptoms; however, the reductions in itching and redness were significantly greater with olopatadine compared with cromolyn (both variables, P < 0.05). The difference in physicians' impression of overall improvement on days 30 and 42 significantly favored olopatadine over cromolyn (both days, P < 0.05). Most patients (62.2%) had reacted positively to grass pollen at baseline. The regression slopes correlating itching and redness with pollen count were 5 times lower for olopatadine compared with cromolyn (P = 0.002 and P = 0.016, respectively), indicating that olopatadine's efficacy increased as the pollen count increased.

CONCLUSIONS

Six weeks' instillation of olopatadine 0.19% ophthalmic solution BID had a significantly greater effect on the ocular signs and symptoms of allergic conjunctivitis compared with 6 weeks' instillation of cromolyn 2% ophthalmic solution QID. Both treatments were well tolerated by patients in all age groups; however, olopatadine appeared to have better local tolerability in children aged <11 years.

Comparison of emedastine 0.05% or nedocromil sodium 2% eye drops and placebo in controlling local reactions in subjects with allergic conjunctivitis

PURPOSE

To assess the efficacy of nedocromil sodium 2% eye drops and emedastine difumarate 0.05% eye drops in controlling the ocular allergic reaction induced by conjunctival allergen challenge (CAC).

METHODS

Thirty subjects with a personal history of allergic conjunctivitis were enrolled (first visit). At the second visit each subject randomly received emedastine 0.05% or nedocromil 2% in one eye and placebo in the other eye. Five minutes after the medication the offending allergen was instilled in both eyes. Ocular redness and itching were evaluated according to a standardized scoring system at 3, 10 and 20-minute intervals after instillation of the allergen. After one week (third visit) the whole procedure was repeated using the placebo in the eye used as control during second visit and one of the trial drug that was not used at second visit in the other eye (either emedastine or nedocromil).

RESULTS

Emedastine 0.05% and nedocromil 2% eye drops were more effective than placebo in controlling ocular redness and itching (p<0.01). Emedastine was more effective (p<0.01) than nedocromil in alleviating redness and itching 3 and 10 minutes after application of the allergen.

CONCLUSIONS

Emedastine 0.05% appeared superior to nedocromil 2% in producing immediate relief when subjects with allergic conjunctivitis were exposed to the offending allergen.

Update on ocular allergy treatment

Allergy affects > 15% of the world population with a higher prevalence of 30% in westernised industrialised countries, such as the US. Allergy commonly affects various target organs including the eyes, nose, sinuses, ears, lungs and skin. However, the ocular component may be the most common and initially the most prominent disabling feature. Some patients are affected for only a few weeks to months while others have symptoms that last throughout the year. The associated healthcare costs related to allergic conjunctivitis has been commonly nestled with allergic rhinitis and has been reported to be as high as US$5.9 billion in the US, with 25% (US$1.5 billion) of it related to medication use. The expenditures related to ocular prescription medication has only recently risen in the past decade from US$6 million in early 1990s to > US$200 million in the new millennium with a projected continuous expansion of 25% per year. This appears to be due to improved prescription medications and their clear benefit over the less efficacious over-the-counter products. The actual cost of the medications and their relative price increases over the past year have ranged from 0 - 49% with an average cost of < US$ day. The newer topical medications (multiple acting agents) are focusing on multiple actions that include an antihistaminic effect to provide an immediate relief and additional delayed effects to act on the mediators of the late phase reaction without steroid side effects (glaucoma, cataracts). The paradigm for the treatment of ocular allergy ranges from primary measures (avoidance measures, cold compresses and lubrication), to secondary measures (various combination of topical agents) and tertiary measures that would include topical steroids and immunotherapy. The increased interest in advancing ocular treatment will lead to the development of additional therapies, novel pharmacokinetic delivery systems and, thus, improved healthcare outcomes for patients with allergic conjunctivitis.

Nedocromil sodium eye drops are more effective than sodium cromoglycate eye drops for the long-term management of vernal keratoconjunctivitis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a severe though transient form of ocular allergy, predominant in young males, which requires careful management. Corticosteroids are effective but also cause serious topical side-effects in the eye, such as glaucoma and cataracts. The safer, mast cell stabilizing anti-inflammatories (commonly sodium cromoglycate) therefore have an important role. This parallel group study compared efficacy, tolerability and safety of sodium cromoglycate 2% with nedocromil sodium 2%, administered as one drop per eye four times daily for a period of 5 months.

METHODS

Children aged 4-17 years, with a diagnosis of mostly limbal VKC in the last 12 months, entered a 2-week baseline during which they used only artificial tears, and were then randomized to treatment, in groups of 18, on an investigator single-masked basis. Daily symptom diary cards were kept by patients/guardians, and VKC was assessed by the clinician at approximately monthly intervals. Dexamethasone was provided for rescue control of severe symptoms, if needed.

RESULTS

A total of 34 patients completed the study. Both trial treatments produced rapid improvements and many ocular signs and symptoms, including Trantas' dots, chemosis, itching, soreness and sticky discharge, were fully controlled by the end of the study. However, nedocromil sodium took effect more quickly, with a significant reduction compared to sodium cromoglycate for itching, grittiness, hyperaemia and keratitis within 6 weeks. In addition, nedocromil sodium was the more efficacious overall (significant vs sodium cromoglycate for hyperaemia, keratitis, papillae and pannus at 22 weeks). Both treatments were well tolerated and without serious adverse effects. Final opinions favoured nedocromil sodium, with full control of VKC recorded for 94% (patient opinion) and 100% (clinician opinion) of this treatment group, compared with 29% and 0%, respectively, in the sodium cromoglycate group.

CONCLUSIONS

Nedocromil sodium 2% eye drops is significantly more effective than sodium cromoglycate for treatment of VKC.

Efficacy of nedocromil 2% versus fluorometholone 0.1%: a randomised, double masked trial comparing the effects on severe vernal keratoconjunctivitis

AIMS

To compare the efficacy of topical nedocromil 2% with fluorometholone 0.1% in vernal keratoconjunctivitis (VKC).

METHODS

In a double masked random design, 24 patients with severe vernal keratoconjunctivitis were placed at random on nedocromil 2% eye drops in one eye and fluorometholone 0.1% in the fellow eye. At the end of the 2 week treatment period, the patient crossed over the eye drops (if asymptomatic in one eye), or continued with nedocromil sodium in both eyes (if asymptomatic in both eyes). All patients were examined weekly and ocular surface temperature recorded for a period of 6 weeks.

RESULTS

Improvement in the watering, discharge, conjunctival hyperaemia, papillary hypertrophy, and Trantas' dots was noted in both groups, but overall fluorometholone was significantly more effective than nedocromil. Eyes treated with fluorometholone showed a significant decrease in ocular surface temperature compared with nedocromil treated eyes (p = 0.03).

CONCLUSIONS

Both nedocromil and fluorometholone were effective in ameliorating the signs and symptoms of vernal keratoconjunctivitis. No adverse effects were noted in the nedocromil group.

Treating severe eye allergy

Allergic eye conditions, particularly seasonal allergic conjunctivitis (SAC), are common. Itching, oedema and hyperaemia are relieved with topical H1-antagonists or sodium cromoglycate. The newer mast-cell stabilizing agent nedocromil sodium has a similar safety profile to sodium cromoglycate, but is more potent and has a more convenient twice-daily dosing regimen. When several placebo-controlled studies of its use in the treatment of SAC were analysed, it was found that 80% of patients reported symptom relief. In a further study, nedocromil sodium eyedrops (twice-daily dosing) had similar overall efficacy to sodium cromoglycate eyedrops (four-times-daily dosing) in subjects with SAC during the birch season, but during the period of highest pollen challenge, only the former agent was significantly more effective than placebo. Another study found that nedocromil sodium had efficacy equivalent to levocabastine over 7 days, but tended to have a more rapid onset of action. In patients with perennial allergic conjunctivitis (PAC) unresponsive to sodium cromoglycate, both clinicians and patients reported significantly better control of symptoms with nedocromil sodium eyedrops than with placebo. Recently, in a long-term study of treatment for vernal keratoconjunctivitis (VKC), it was found that nedocromil sodium 2% eyedrops produced a more rapid and marked improvement in symptoms than sodium cromoglycate 2% eyedrops and enabled lower use of steroid rescue medication. Both drugs were well tolerated and without serious side-effects.

Effects of lodoxamide, disodium cromoglycate and fluorometholone on tear leukotriene levels in vernal keratoconjunctivitis

PURPOSE

We compared tear leukotriene B4 (LTB4) and leukotriene C4 (LTC4) levels of vernal keratoconjunctivitis (VKC) patients with those of age-matched controls and evaluated the effects of disodium cromoglycate (DCG) 2%, lodoxamide 0.1% and fluorometholone 0.1% on the tear LTB4 and LTC4 levels of the VKC patients.

METHODS

Thirty VKC patients were divided into three groups and their tear LTB4 and LTC4 levels measured with an enzyme-linked immunoassay technique before and after treatment with either lodoxamide 0.1%, DCG 2% or fluorometholone 0.1%. The results were compared with the tear LTB4 and LTC4 levels of 10 healthy control subjects. During this trial period, clinical scores for signs and symptoms of VKC were also evaluated.

RESULTS

In the VKC patients median tear LTB4 and LTC4 levels were 349.0 pg/ml (range 213.3-707.7 pg/ml) and 225.2 pg/ml (range 196.1-241.1 pg/ml) respectively--significantly higher than the control group (p = 0.0065 for LTB4 and p = 0.0003 for LTC4). After treatment, LTB4 levels decreased significantly in all treatment groups when compared with baseline (for the lodoxamide group, p = 0.01; for the DCG group, p = 0.008; for the fluorometholone group, p = 0.045). LTC4 levels were also significantly reduced after treatment in all three treatment groups (for the lodoxamide group, p = 0.0209; for the DCG group, p = 0.0284; for the fluorometholone group, p = 0.0109).

CONCLUSIONS

Tear LTB4 and LTC4 levels are significantly higher in VKC patients than controls, which points to a possible role of lipoxygenase pathway products in the pathophysiology of ocular allergic disorders. Lodoxamide 0.1%, DCG 2% and fluorometholone 0.1% were all effective in reducing LTB4 and LTC4 levels in VKC.

A multicenter comparison of the ocular efficacy and safety of diclofenac 0.1% solution with that of ketorolac 0.5% solution in patients with acute seasonal allergic conjunctivitis

Only one of several available ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) is currently FDA approved for use in acute seasonal allergic conjunctivitis (SAC). Sixty patients with SAC and moderate itching and bulbar conjunctival injection were enrolled in a multicenter, randomized, double-masked, parallel-group trial comparing diclofenac sodium (DS) with ketorolac tromethamine (KT). Patients instilled 1 drop four times daily while awake for 14 days. Ocular signs and symptoms were evaluated at one and two weeks. The primary efficacy variables were itching and bulbar conjunctival injection. For both treatments, the ocular allergy sign and symptom scores were comparable at baseline. Both treatments evaluated in this study were well tolerated. Significant clinical and statistical reductions from baseline were observed in the primary efficacy variables. Treatment group differences were observed for the pain/soreness score with an advantage observed for the DS group at 30 minutes and at day 7. Our conclusion is that diclofenac sodium and ketorolac tromethamine acted similarly to reduce the ocular signs and symptoms associated with acute seasonal allergic conjunctivitis. There was a statistically significant advantage for the DS group to be free of symptoms at the day 7 visit as compared to the KT group (20.7% vs. 3.2%).

Therapeutic options in ocular allergic disease

The term ocular allergy encompasses a group of diseases in which there is a high frequency of atopy, ocular itching, stringy discharge and a papillary conjunctival reaction. Conditions confined to the lids and conjunctiva (e.g. seasonal allergic conjunctivitis) have a good prognosis but those involving the cornea may result in visual impairment (e.g. atopic keratoconjunctivitis). Mast cell and eosinophil mechanisms are important in al the ocular allergies, but T cell inflammation is prominent only in vernal keratoconjunctivitis, atopic keratoconjunctivitis and giant papillary conjunctivitis. Therapy involves the use of antigen avoidance (where possible), nonspecific medical therapy (e.g. cold compresses, artificial tears), specific medical therapy and, in certain situations, immunotherapy and surgery. Topical antihistamines (often in combination with a vasoconstrictor) and oral antihistamines are widely used in perennial and seasonal conjunctivitis. Levocabastine is a new preparation which is more rapid and potent. Mast cell inhibitors [e.g. sodium cromoglycate (cromolyn sodium)] have a proven track record as safe and effective therapy for all ocular allergic diseases and the newer, more potent nedocromil and lodoxamide are now available. Topical steroids are only indicated in sight-threatening disease due to their serious adverse effects and other therapy should be continued to minimise the dose required. There is a lack of intermediate potency and high potency but safe topical preparations. A number of future possibilities exist, some of which have been partially explored. Cyclo-oxygenase inhibitors have proved of limited use, but inhibitors of lipoxygenase and kinin pathways are awaited. Although results with HEPP have been disappointing, other modulators of mast cell function (e.g. picumast, beta-agonists and phosphodiesterase inhibitors) may prove useful in the future. So far, results with topical cyclosporin in serious disease are very encouraging. Future developments in the manipulation of eosinophilic products, cytokines and adhesion molecules may also be relevant. However, the current situation for those with serious ocular allergy remains a disturbing dependence upon topical steroids, with all the attendant risks.

Comparative therapeutic studies with Tilavist

Comparative clinical trials which include known therapies as well as placebos are essential in constructing a solid basis from which to 'launch' any new drug. This applies especially to eye drops for treatment of seasonal allergic conjunctivitis, where the symptomatology, already dependent on the vagaries of the natural pollen challenge season, is further influenced by a positive washing action of the placebo eye drops. Tilavist (2% nedocromil sodium ophthalmic solution) has therefore been compared with sodium cromoglycate eye drops and non-sedating antihistamine tablets, both mainstays in the treatment of seasonal allergy, in a series of double-masked, placebo-controlled, mainly multicentre studies. Nedocromil sodium, twice or four times daily, proved as effective overall as sodium cromoglycate (2% or 4% four times daily) in three seasonal trials, and was the more effective treatment in a study of patients with vernal keratoconjunctivitis. Its efficacy was most evident during peak periods of pollen challenge, when neither placebo nor sodium cromoglycate eye drops controlled breakthrough symptoms. Three further seasonal studies showed nedocromil sodium eye drops to be as effective as standard oral doses of astemizole and terfenadine, whilst a faster onset of action than terfenadine was reported in one multicentre study.

Therapeutic considerations: symptoms, cells and mediators

Immuno-histopathological studies of conjunctival tissue biopsied from patients with non-sight-threatening allergic conjunctivitis or with sight-threatening allergic keratoconjunctivitis should lead to more effective management of these eye conditions, based on the specific cellular involvement. The major difference between these two categories of eye disease was the occurrence of T-lymphocytes, which were absent in the former but prominent in the sight-threatening disorders. Seasonal and perennial allergic conjunctivitis both showed a heavy mast cell increase, due to infiltration of mucosal type mast cells, and allergen challenge studies linked mast cell histamine release to the early phase reaction occurring within 20 minutes. A second histamine peak at six hours after challenge might implicate basophils (or refractory mast cells) and was accompanied by a rise in eosinophil cationic protein. In sight-threatening, chronic allergic keratoconjunctivitis the responses were clearly directed by T-cells, themselves the primary effector cell in atopic keratoconjunctivitis, whereas vernal keratoconjunctivitis displayed a T-cell driven eosinophilia, with increased expression of the adhesion molecules involved in tissue invasion by these cells. Appropriate therapies for each different category of conjunctivitis should be based on the specific immunopathology, and directed at the activated cell types that are primarily responsible for the disease process.

Clinical experience with Tilavist: an overview of efficacy and safety

A programme of clinical studies was carried out to determine the basic efficacy and safety of 2% nedocromil sodium eye drops (Tilavist) in treating allergic conjunctivitis, in 2,905 patients from 3-76 years of age. Results of all the double-masked placebo comparative studies completed to date-five in vernal keratoconjunctivitis (VKC), five in perennial (PAC) and 16 in seasonal allergic conjunctivitis (SAC)-have been assessed in a statistical overview analysis. Nedocromil sodium, administered four times daily to 153 patients with VKC, was significantly more effective than placebo (155 patients) and in the clinicians' opinion gave good control in 76% of cases, compared with 46% for placebo (p < 0.001). Patients with chronic symptoms of PAC also responded better to nedocromil sodium given four times daily (n = 146) rather than twice daily (n = 86), and significantly more patients (p < 0.001) were effectively controlled by four times daily treatment with nedocromil sodium (72%) than with placebo (47%; n = 156). Twice-daily dosage with nedocromil sodium (n = 677) was adequate for SAC, however, and the treatment was statistically better than placebo (p < 0.01-p < 0.001) whether dosed twice or four times daily. Speed of action was assessed in seven SAC studies in which 79% of all patients (n = 295) using nedocromil sodium had experienced relief of symptoms when questioned, half of them within 15 minutes and 74% during the first hour after dosing. Test treatments were well-accepted by both adults and children, and there were no major adverse events. Minor irritations reported more frequently with nedocromil sodium than placebo were stinging or burning of the eyes on application of the drops and a distinctive taste, noted by 5% of the active treatment group (n = 1,552).

The pathophysiology of ocular allergy: current thinking

Seasonal allergic conjunctivitis is the only ocular disease to involve solely Type-1 hypersensitivity, the other main forms of ocular allergy--perennial allergic conjunctivitis, vernal and atopic keratoconjunctivitis and giant papillary conjunctivitis--each having a more complex immunological basis and a chronic inflammatory component. Involvement of secondary inflammatory cells, particularly eosinophils, in addition to the mast cells resident in the conjunctival substantia propria, can lead to more serious corneal damage with vision-threatening potential. Thoughtful management of allergic conjunctivitis is needed in order to control the ocular inflammation without incurring steroid-induced side-effects, and patient education is also an important factor in maintaining optimal allergen avoidance, especially in the more severe and chronic cases. Laboratory models can be helpful in assessing the potential of new drugs, and SWR mice (topically sensitised and challenged with short ragweed) show clinical signs of allergic conjunctivitis, together with mast cell and eosinophil involvement, remarkably similar to the human pathophysiology. The antiinflammatory activity of both steroids and nedocromil sodium observed in this animal model supports therapeutic evidence of the usefulness of second-generation mast cell stabilising drugs in the treatment of ocular allergy.