Phase 3 Clinical Study of IVIG for Efficacy and Safety in Patients with Autoimmune Encephalitis
Ko Sakamoto1, Satoshi Kamei2, Keiko Tanaka4, Osamu Watanabe5, Makoto Hara6, Yukitoshi Takahashi7, Keizo Yasui8, Shigeru Nogawa9, Keiko Tokunaga3, Emma Sasaki1, Atsushi Kuga1, Hakan AY10, Takashi Kanda11
1Takeda Pharmaceutical Company Limited, 2Center for Neuro-Infections, 3Department of Neurology, Ageo Central General Hospital, 4Department of Animal Model Development, Department of Multiple Sclerosis Therapeutics, Brain Research Institute, Niigata University, Fukushima Medical University School of Medicine, 5Department of Neurology, Kagoshima City Hospital, 6Division of Neurology, Department of Medicine, Nihon University School of Medicine, 7Department of Clinical Research, NHO, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, 8Department of Neurology, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, 9Department of Neurology, Tokai University Hachioji Hospital, 10Takeda Development Center Americas, Inc, 11Neuromuscular Center Yoshimizu Hospital
Objective:
This study aimed to investigate the efficacy and safety of intravenous immunoglobulin (IVIG) in patients with autoimmune encephalitis (AE) refractory to steroid pulse therapy.
Background:
The efficacy of IVIG for AE has not been clearly established in controlled clinical studies.
Design/Methods:
In this randomized, double-blind, active-controlled, parallel-group study (NCT05177939), patients who showed insufficient improvement after steroid pulse therapy were enrolled. Patients were randomly assigned in a 1:1 ratio to receive either IVIG or control (steroid pulse therapy). The primary endpoint was the proportion of responders where response was defined as ≥40% improvement in the Clinical Assessment Scale in Autoimmune Encephalitis at Week4. Other scales including modified Rankin Scale (mRS) were examined for secondary efficacy endpoints.
Results:
A total of 40 patients were randomized. The primary analysis population included patients with cell-surface antigen antibodies (n=7 in the IVIG group and 3 in the control group). The proportion of responders was 57.1% (95% CI: 18.405, 90.101) in the IVIG group and 0% (95% CI: 0.000, 70.706) in the control group. Secondary analysis in the full analysis set (n=20 per group) showed response rates of 50.0% (95% CI: 27.196, 72.804) and 25.0% (95% CI: 8.657, 49.105). Secondary endpoints, including mRS, supported the primary results. The incidence of adverse events was similar between groups, mostly mild or moderate.
Conclusions:
In patients with AE refractory to steroid pulse therapy, IVIG provided benefits with no safety concerns.
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