Tofacitinib treatment for refractory autoimmune encephalitis

To treat intractable cases of autoimmune encephalitis, the need for novel immunotherapy that penetrates the blood‐brain barrier (BBB) is increasing. Tofacitinib is a Janus kinase (JAK) inhibitor used to treat refractory immune‐mediated diseases that effectively penetrates the BBB. Accordingly, tofacitinib could be a new option for patients with refractory autoimmune encephalitis. Patients treated with tofacitinib were selected from Seoul National University Hospital cohort for autoimmune encephalitis from April 2019 until July 2020. We retrospectively analyzed the efficacy of tofacitinib in patients with autoimmune encephalitis who showed insufficient responses to multimodal conventional immunotherapies. Tofacitinib was administered orally at a dose of 5 mg twice daily. A total of eight patients were treated with tofacitinib; two had good responses (clinical global impression‐improvement score [CGI‐I] = 1 or 2), three had partial responses (CGI‐I = 3), and three showed no significant improvements (CGI‐I = 4) in response to tofacitinib. The two good responders showed the improvement of chronic autoimmune meningoencephalitis and the cessation of the new‐onset refractory status epilepticus in anti‐myelin oligodendrocyte glycoprotein (MOG)–associated disorder, which was previously intractable to anesthetics and the other immunotherapies. No patients had serious side effects. Our findings suggest the potential of tofacitinib as a therapeutic option for central nervous system autoimmune diseases.