The Role of Tocilizumab in Glucocorticoid Resistant Giant Cell Arteritis: A Case Series and Literature Review

Background: Glucocorticoid-resistant giant cell arteritis (GCA) describes a subgroup of patients whose visual acuity further declines despite immediate administration of high-dose intravenous glucocorticoids. Tocilizumab, a recombinant humanized anti-interleukin-6 receptor monoclonal antibody may be used as "rescue" therapy in these cases but requires more research.

Methods: We present a literature review on tocilizumab as rescue therapy and a retrospective case series of 5 consecutive glucocorticoid (GC) resistant, temporal artery biopsy (TAB) negative patients. 

Results: The use of tocilizumab as rescue therapy for GC-resistant GCA is limited to 3 case reports. Two cases saw visual acuity improvement in the newly affected contralateral eye after 8 mg/kg of intravenous tocilizumab (from 6/60 to 6/15 in one case and hand motion to 6/6 in another). The third described stabilization and prevention of further best-corrected visual acuity (BCVA) decline. All 5 of our patients presented with acute monocular vision loss. BCVA ranged from 6/12 to light perception (LP). All patients were promptly commenced on 1 g intravenous methylprednisolone daily. Weekly 162 mg of subcutaneous tocilizumab was commenced once contralateral eye involvement was noted. Tocilizumab resulted in bilateral BCVA gains in 2 cases, recovery of the contralateral eye in one, and no effect in the remaining 2 cases. BCVA recovery was no light perception to 6/6 after 6 weeks of tocilizumab. Tocilizumab had no effect in cases with severe vision loss and high C-reactive protein on presentation. 

Conclusions: We agree with existing hypothesis that tocilizumab likely prevents a "pending" central retinal artery occlusion by maintaining retinal vasculature perfusion. Our case series suggests that there is a role for tocilizumab as "rescue" therapy for GC-resistant GCA, where vision loss would otherwise be imminent.