Phase 2/3 Study of Rituximab for Graves' Ophthalmopathy

Laboratory evidence suggests that autoantibodies targeting the thyrotropin receptor are directly involved in the pathogenesis of Graves' ophthalmopathy (GO). This double-blind, randomized, controlled study will determine whether rituximab, an anti-B-lymphocyte antigen (CD20) monoclonal antibody that induces transient B-cell depletion, is an effective treatment for moderate to severe, active GO.

Before any treatment is given, careful eye and thyroid physical examinations will be performed and the patients will have several thyroid blood tests, a test to count the white cells in the blood, and a CT scan of the head and eyes. A close-up photograph of the face will be taken and patients will be given a short questionnaire about how their eyes are feeling and how the eye disease is affecting their quality of life.

Each study subject will receive either 2 infusions of rituximab (each 1000 mg; given 2 weeks apart) or 2 intravenous infusions of saline. Glucocorticoids (methylprednisolone 100 mg) or saline will also be administered IV as premedication to the rituximab and placebo arm respectively, in a blinded fashion but matching the randomization, to decrease the rate of infusion-associated reactions. All antihypertensive medications will be held for the 12 hours prior to and during the infusion. Patients will return 2 weeks after the first intravenous infusion in order to receive the second infusion.

Patients will be assessed at weeks 8, 16, 24 and 52 for eye disease severity, CAS, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroid autoantibodies (TRAB), thyroid peroxidase (TPO) and C19+B cell count. CT scan of the orbits will be obtained at baseline and week 52 for orbital volume measurements and proptosis. Thyroid ultrasound will be obtained at baseline, week 24 and week 52 for thyroid volume measurements and color Doppler flow assessment.

Data analysis - Continuous variables were compared between the two treatment groups using t test or the Wilcoxon rank sum test, while categorical variables were analyzed using the chi-square /Fisher exact test. Non-parametric methods were used throughout where normality and chi-squared assumptions did not hold. General linear models were used to access treatment effect on change in CAS between baseline and 24 or 52 weeks. Patients who discontinued the trial prior to week 52 were evaluated before discontinuation and those data were carried forward to either 24 weeks (for the 5 patients who discontinued prior to or at week 24) or 52 weeks (for the single patient discontinued from the trial after 24 weeks) as the final evaluation for that patient. A p-value < 0.05 was considered significant.