Tocilizumab in Thyroid Eye Disease: A Rescue After Teprotumumab?

Summary: Thyroid eye disease is an autoimmune condition with an incidence of 16/100,000 women in the United States. The standard of care for active thyroid eye disease most commonly involves corticosteroids as the first-line agent to manage the acute inflammatory phase. The disease course can last anywhere from 6 to 36 months, with 20–30% of patients not responding to initial steroid treatment1. Prolonged steroid exposure further increases the risk of adverse effects, underscoring the need for alternative therapeutic approaches, including steroid-sparing agents. Teprotumumab (Tepezza) is a monoclonal antibody that targets insulin-like growth factor 1 receptor (IGF-1R) that has shown success in treating proptosis and diplopia associated with thyroid eye disease (TED). However, there are still several patients who remain symptomatic after this treatment. Prior studies have highlighted the use of tocilizumab (Actemra) in recalcitrant cases, however, conclusions about the efficacy of use have been controversial. Rheumatologists are experienced in managing multisystem autoimmune diseases and are well-versed in deploying steroid-sparing medications like interleukin 6 (IL-6) inhibitors, of which three are commercially available. Here we present a case of a 51-year-old female with thyroid eye disease who relapsed after treatment with teprotumumab. She was started on tocilizumab, an IL-6 inhibitor, with complete subjective resolution of ocular symptoms within two days, followed by objective improvement documented by oculoplastics within a few months. When tocilizumab treatment was delayed, her symptoms returned. This case highlights the potential therapeutic benefit of sequential IL-6 inhibitor use after teprotumumab in TED, particularly in patients with chronic inflammatory disease. This may suggest a potential synergistic benefit of dual IGF-1 and IL-6 inhibition for sustained improvement in a subset of TED patients. With rheumatology co-management, patients may require less systemic steroid use, thereby minimizing treatment-associated adverse effects. Future studies are needed to further evaluate the relationship between dual IL-6 and IGF-1R inhibition in TED management. Additional clinical trials and regulatory approval would be necessary to expand access to IL-6 inhibitors for this indication, potentially improving patient outcomes with refractory TED.