Management of Severe Hypersensitivity Reaction to Rituximab with Obinutuzumab in Patients with IgG4-Related Ophthalmic Disease

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A 40-year-old man with IgG4-related ophthalmic disease experienced severe hypersensitivity reactions to rituximab after partial response to glucocorticoids and mycophenolate mofetil.
2

Obinutuzumab was administered after rituximab was discontinued, resulting in no infusion reactions and significant clinical improvement within one month.
3

Serum IgG4 levels decreased from 861 mg/dL to 49.1 mg/dL, and repeat imaging showed substantial reduction in lacrimal-gland enlargement after obinutuzumab treatment.
4

Obinutuzumab may offer a viable treatment alternative for patients intolerant to rituximab in IgG4-related disease, although its use is currently off-label.
5

The case highlights the potential of obinutuzumab in managing IgG4-related orbital involvement, but further studies are needed to confirm its efficacy and safety.

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