Uveitis, a set of conditions defined by intraocular inflammation, is a significant cause of vision loss and morbidity in the United States and the world. The incidence was recently estimated to be more than 50 cases per 100,000 person-years, with a prevalence of approximately 115 per 100,000 persons. Additionally, uveitis is believed to be the cause of up to 10% of cases of legal blindness in the United States, or approximately 30,000 new cases of blindness per year. In contrast to common age-related eye disorders, uveitis may have a stronger socio-economic impact because it disproportionately affects younger working-age patients. Although the etiology of uveitis is varied, most cases are presumed to be immune-mediated and lack a known infectious cause. Even in developing countries such as India that have a larger burden of infection, the vast majority of cases are non-infectious.
The current mainstay of treatment for noninfectious uveitis is corticosteroids (topical, systemic, locally injected, or corticosteroid-eluting implants). Due to the well documented local and systemic side effects associated with corticosteroid therapy, other immunosuppressive therapies are frequently used as corticosteroid-sparing agents in patients who need long-term therapy. These include antimetabolites, calcineurin inhibitors, alkylating agents, and biologic drugs. Cost and morbidity associated with uncontrolled inflammation make the selection of an effective initial steroid-sparing agent extremely important.
It is common practice for patients requiring a steroid-sparing agent to be treated first with the less expensive methotrexate and then switched to mycophenolate mofetil in the event of treatment failure. However, results from non-comparative retrospective case series indicate that uveitis patients may be much more likely to achieve controlled inflammation and tolerate treatment with mycophenolate mofetil. Furthermore, approximately half of the patients who fail treatment with methotrexate go on to successful treatment with mycophenolate mofetil. There have been no prospective randomized, controlled trials to systematically determine which antimetabolite is more clinically efficacious as initial corticosteroid-sparing therapy, making it difficult for clinicians to make informed, evidence-based decisions about first-line immunosuppressive treatment.
Our contribution is expected to be a definitive understanding of the comparative efficacy, tolerability, and quality of life of these two antimetabolites as initial steroid-sparing therapy for uveitis patients requiring chronic therapy. This contribution is significant because it will enable clinicians to make evidence-based decisions when prescribing first-line immunosuppressive therapy for their uveitis patients. The use of optimal first-line therapy will improve quality of life by reducing the risk of vision loss and complications associated with uncontrolled ocular inflammation and long-term corticosteroid use.
