Efficacy of ofatumumab combined with corticosteroids in the treatment of autoimmune encephalitis: a 6-month cohort study.

Objective: This study investigated the efficacy of ofatumumab (OFA) combined with corticosteroids in autoimmune encephalitis (AE) patients refractory to conventional treatment.

Methods: Eighteen AE patients admitted to Ruijin Hospital between June 2022 and September 2023 received four subcutaneous 20-mg OFA injections at 0, 1, 6, and 12 weeks combined with standard corticosteroid therapy.

Results: Clinical symptoms, modified Rankin scale (mRS) scores, Clinical Assessment Scale for Autoimmune Encephalitis (CASE) scores, serum immunoglobulin (Ig) levels (IgG and IgM), and peripheral blood CD20 + B cell levels were documented before OFA administration and at 1, 2, 6, 12, and 24 weeks post-treatment. OFA treatment significantly improved psychiatric symptoms (P = 0.025), cognitive dysfunction (P = 0.008), and seizure frequency (P = 0.014). The mRS and CASE scores improved after two injections in patients with anti-NMDAR encephalitis (P = 0.041), but not in patients with anti-LGI1 encephalitis (P > 0.05). The mRS scores significantly improved at 12 weeks post-treatment in antibody-negative encephalitis. Blood CD20 + B cell levels dropped to zero after an average of 2.5 injections. No significant changes could be observed in serum IgG and IgM levels (P > 0.05). Seven patients had mild fever or pulmonary infections post-treatment.

Conclusion: This study suggests that OFA is a safe and effective treatment for a subset of AE patients, particularly in cases of anti-NMDAR encephalitis, though further research is needed on long-term outcomes and recurrence.