Rapidly Progressive Cognitive Decline and Varicella Zoster Blisters Associated With Teprotumumab in 2 Patients With Graves’ Orbitopathy

Abstract

Abstract Introduction: Teprotumumab, an IGF-1R antagonist, was approved for treatment of Graves’ orbitopathy (GO) in 2020. Common side effects include nausea, diarrhea, muscle spasms, hearing impairment, dysgeusia, headache, dry skin, infusion reactions, and hyperglycemia. We report here 2 cases of unexpected adverse effects. Patient #1 is a 76-year-old man with Graves’ disease diagnosed in 2018, treated with methimazole 2.5mg every other day. His GO manifestations included diplopia, proptosis, and exposure keratopathy. Past history was significant for hypertension, hyperlipidemia, and prostate hyperplasia. He lived independently and walked several miles daily. Teprotumumab was initiated. Between the 4th and 5th doses, his family noted 6-weeks of rapidly progressive cognitive decline characterized by behavioral changes, confabulation, memory deficit, delirium/delusions/mania. He was admitted to neurology service and subsequent doses held. Lumbar puncture was unremarkable. TFT was normal before, during and after stopping teprotumumab. Thyroid antibodies were notable for elevated TSI but normal thyrotropin receptor Ab and TPO/TgAb. Other labs: IL2, IL6, ESR, CRP, heavy metals, IgG, IgM, SARS-CoV-2 IgM/IgGs, vitamins B1, B6, and B12 were all normal. His most recent repeat TPO Ab was 14 IU/mL (increased from <6), TgAb 18.4 IU/mL (increased from <1.0). EEG showed no epileptiform activity. Head MRI/MRA showed cerebral amyloid angiopathy without stenosis or aneurysms in the intracranial arterial vasculature. Symptoms progressed with IV glucocorticoids and IV Ig therapy. He subsequently underwent plasmapheresis with resolution of symptoms. Patient #2 is a 48-year-old man with Graves’ disease and GO diagnosed in 2018, initially treated with methimazole and subsequently underwent total thyroidectomy in 2019. Patient is euthyroid on levothyroxine. Ophthalmic signs and symptoms included significant proptosis and retrobulbar pain. He was started on teprotumumab infusions. After his 4th dose, he noted painful vesicles in a dermatomal distribution on his right posterior thigh. Direct fluorescent antibody stain was positive for varicella zoster, and rashes resolved with valacyclovir therapy. Discussion: Paraneoplastic/autoimmune encephalitis syndromes can be associated with antibodies to neuronal cell surfaces/synaptic proteins and may occur in the presence or absence of cancer. The incidence of varicella-zoster virus infection is associated with the immune status of the patient, disease-related immunocompromised, or iatrogenic immunosuppression, with age being the major risk factor for 90% of adult cases. This could be incidental, or related to other disorders, or perhaps teprotumumab may have activated auto-immunity. The exact mechanisms for rapidly progressive cognitive decline and shingles remains unclear.