Perelman School of Medicine at the University of Pennsylvania

Center for Preventive Ophthalmology and Biostatistics (CPOB)

Multicenter Uveitis Steroid Treatment (MUST) Trial

The Multicenter Uveitis Steroid Treatment (MUST) Trial is a randomized clinical trial that compares an intraocular corticosteroid implant to standard oral therapy for the treatment of patients with severe, vision-threatening uveitis.

What is Uveitis and Why is the MUST Trial Important?

Uveitis refers to intraocular inflammation of various kinds.  Ocular inflammatory diseases are the fifth or sixth leading cause of blindness in the United States.  In addition to producing vision loss, especially when unrecognized or treated improperly, other frequent complications include cataract; glaucoma; chorioretinal scarring; and cystoid macular edema, the most common cause of decreased vision from uveitis.  Retinal detachment and neovascularization of the retina, optic nerve, or iris are less frequent—but potentially severe—complications of uveitis.

Uveitis that affects primarily the vitreous (intermediate uveitis), the retina and choroid (posterior uveitis), or the entire eye (panuveitis) have particularly high rates of vision loss.  The peak onset of uveitis is in young adulthood.  A failure to control the disease can result in a substantial number of years of vision loss.  Many of these diseases are chronic, requiring long-term therapy to maintain control of disease.

Current treatment for patients with severe, vision-threatening uveitis typically involves the use of systemic medications, primarily oral corticosteroids, supplemented by immunosuppressive drugs in selected situations.  Such systemic treatments are, unfortunately, associated with side effects.

A new way to deliver corticosteroids to the eye is through an intraocular implant.  One implant, called the fluocinolone acetonide intraocular implant, is a surgically implanted reservoir of corticosteroid designed to last 2.5 to 3 years and to provide long-term control of uveitis.  Because of the potential for controlling uveitis while minimizing systemic side effects, the use of the implant may alter the way in which uveitis is treated. This treatment is associated with high rates of local side effects.  To date, there have been no large-scale, NIH-funded, multicenter clinical trials comparing these alternative treatments to determine which is best for management of the worst cases of uveitis.

The goal of the MUST Trial is to compare the fluocinolone acetonide implant to oral therapy (the previous standard of care) for the treatment of patients with severe, vision-threatening intermediate, posterior, or panuveitis.


The primary outcome for the MUST trial is change in visual acuity.  Secondary outcomes include ability to control the uveitis, resolution of macular edema (a major cause of visual loss in these patients), and the presence of ocular and systemic side effects from both the uveitis and the treatments.  Additional benefits include epidemiologic information concerning long-term outcomes of treatment for uveitis and immunosuppressive drugs.

Study Status

The study is currently open for enrollment.

CPOB’s Role in the SITE Study

John Kempen, MD, PhD, CPOB’s Director of Ocular Epidemiology, is the national Vice-Chairman of the Multicenter Uveitis Steroid Treatment (MUST) trial.

For more information on the MUST Trial, contact Dr. John Kempen or click here to go to the MUST website.