Ocular allergy: update on clinical trials

Identifying and addressing common contributors to nonadherence with ophthalmic medical therapy

PURPOSE OF REVIEW

To discuss common reasons for nonadherence and review existing and emerging options to reduce nonadherence with ocular medical therapy and optimize therapeutic outcomes.

RECENT FINDINGS

Nonadherence can arise from patient-related issues (e.g. physical, cognitive) and healthcare-related issues (e.g. cost, access to care). Multiple strategies have been developed and evaluated to overcome these barriers to adherence. Identifying nonadherence and its cause(s) facilitates the development of strategies to overcome it.

SUMMARY

Many common causes of nonadherence can be mitigated through a variety of strategies presented.

Efficacy of montelukast in preventing seasonal recurrence of vernal keratoconjunctivitis in children

BACKGROUND

Vernal keratoconjunctivitis is a chronic, seasonally exacerbated, allergic inflammation of the eye. The study aims to evaluate the efficacy and safety of oral montelukast in treating vernal keratoconjunctivitis in pediatric patients.

METHODS

This is a 26-week, prospective, randomized, open-label study. Fifty-eight patients were randomly assigned to two groups-the treatment (montelukast) and control groups. At the beginning of the study, both the groups received topical loteprednol etabonate (0.1%) in tapering doses for a month, and topical olopatadine (0.1%) for the first 3 months. Symptoms and signs observed before and after treatment and assigned scores were studied. The primary efficacy endpoint was change in the mean score on the visual analog scale (VAS) for each subjective symptom. The secondary efficacy endpoint was change in the total score of objective signs.

RESULTS

The montelukast group showed clinically relevant improvements in the signs and symptoms of vernal keratoconjunctivitis, compared to the control group. There was considerable improvement in clinical signs. Individual symptoms such as redness, itching, foreign body sensation, and tearing showed significant improvement at 6 months follow-up. The gradual improvement in symptoms until the last visit was statistically more significant within montelukast group. Mean VAS score showed statistically significant improvement in itching (p < 0.001) and redness (p < 0.008) in montelukast group even at 3 months. No adverse events were reported in either group.

CONCLUSIONS

Montelukast was found to be safe and effective as a long-term therapy to prevent relapse in moderate to severe vernal keratoconjunctivitis.

Current Knowledge in Allergic Conjunctivitis

Allergic conjunctivitis is a disease of increasing prevalence that affects both children and adults and causes significant deterioration of their quality of life and sometimes irreversible visual damage. There are various forms of the disease, some are allergen-induced such as seasonal and perennial allergic conjunctivitis, giant papillary conjunctivitis, and contact allergic blepharoconjunctivitis, whereas others are not always explained by allergen exposure, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. We review their clinical course, characteristics, and differential diagnosis, and highlight recent advances in their pathophysiology and treatment.

Nanotechnology for the Treatment of Allergic Conjunctival Diseases

Allergic conjunctivitis is one of the most common external eye diseases and the prevalence has been increasing. The mainstay of treatment is topical eye drops. However, low bioavailability, low ocular drug penetration, transient resident time on the ocular surface due to tear turnover, frequent topical applications and dependence on patient compliance, are the main drawbacks associated with topical administration. Nanotechnology-based medicine has emerged to circumvent these limitations, by encapsulating the drugs and preventing them from degradation and therefore providing sustained and controlled release. Using a nanotechnology-based approach to load the drug is particularly useful for the delivery of hydrophobic drugs such as immunomodulatory agents, which are commonly used in allergic conjunctival diseases. In this review, different nanotechnology-based drug delivery systems, including nanoemulsions, liposomes, nanomicelles, nanosuspension, polymeric and lipid nanoparticles, and their potential ophthalmic applications, as well as advantages and disadvantages, are discussed. We also summarize the results of present studies on the loading of immunomodulators or nonsteroidal anti-inflammatory drugs to nano-scaled drug delivery systems. For future potential clinical use, research should focus on the optimization of drug delivery designs that provide adequate and effective doses with safe and satisfactory pharmacokinetic and pharmaco-toxic profiles.

The allergic eye: recommendations about pharmacotherapy and recent therapeutic agents

PURPOSE OF REVIEW

Ocular allergies affect an estimated 40% of the population, 98% of which are because of allergic conjunctivitis. With the current advent of both repurposed drugs for ocular allergies, as well as novel drugs and methods of administration, there is a need for an updated review of current available medications. A clear characterization of each treatment will ultimately allow treating physicians to restore patients' quality of life and decrease burden of disease.

RECENT FINDINGS

Currently, there are a number of reformulated antihistamines, with cetrizine being the most recent ophthalmic solution available. Nevertheless, there is ongoing research in the field of immunotherapy, steroids, flavonoids, cannabis, and drug-delivery systems.

SUMMARY

Although dual-activity agents remain the keystone for treatment, newer drugs and drug-delivery systems offer other novel directions for delivering appropriate relief with minimal adverse effects.

The Role of Th17 Cells and IL-17 in Th2 Immune Responses of Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common allergic disease that is often associated with the onset of rhinitis or asthma. The incidence of AC has increased significantly in recent years possibly due to air pollution and climate warming. AC seriously affects patients' quality of life and work efficiency. Th (T-helper) 2 immune responses and type I hypersensitivity reactions are generally considered the basis of occurrence of AC. It has been found that new subpopulations of T-helper cells, Th17 cells that produce interleukin-17 (IL-17), play an important role in the Th2-mediated pathogenesis of conjunctivitis. Studies have shown that Th17 cells are involved in a variety of immune inflammation, including psoriasis, rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, and asthma. However, the role of Th17 and IL-17 in AC is unclear. This paper will focus on how T-helper 17 cells and interleukin-17 are activated in the Th2 immune response of allergic conjunctivitis and how they promote the Th2 immune response of AC.