Response to tocilizumab treatment in Graves' ophthalmopathy by measuring rectus muscle thickness and chemosis using optical coherence tomography

To assess the extraocular muscle thickness and chemosis after treatment with tocilizumab in patients with active Graves' ophthalmopathy by optical coherence tomography. Case series of five patients with active Graves' ophthalmopathy (clinical activity score ≥4/10) treated with 4 doses of tocilizumab. These patients had been previously treated with corticosteroids with no response. Spectral-domain optical coherence tomography was employed to determine lateral and medial rectus muscle thickness and chemosis before and after 4 doses of tocilizumab given monthly. Scanning was performed at 3 and 9 o'clock (nasal and temporal). The study included four women and one man with a median age of 52 years (range: 38-73). Median Graves' ophthalmopathy activity duration was 17 months (12-18). Median medial rectus and determine lateral thicknesses pre-treatment were 249μm (174-366) and 337μm (142-443), respectively. Median chemosis was 409μm (290-610). After tocilizumab treatment, median muscle thicknesses reduced to 157μm (88-187) and 197μm (99-290), respectively (P=.043; Wilcoxon) and chemosis to 59μm (0-78). Median clinical activity score decreased from 5 (4-8) to 1 (0-3). A reduction in extraocular muscle thickness and chemosis was observed after treatment with tocilizumab in Graves' ophthalmopathy patients using an optical coherence tomography, so this technique could be a useful complementary technique to assess the therapeutic responses.