Efficacy and safety of different oral prednisone tapering courses in adult anti‐NMDAR encephalitis: A multicenter prospective cohort study

Abstract Objective In adult anti‐ N ‐methyl‐ d ‐aspartate receptor (NMDAR) encephalitis, corticosteroids are commonly used as first‐line treatment. However, the optimal oral prednisone tapering (OPT) following intravenous methylprednisolone pulse therapy remains unclear. We aim to compare the efficacy and safety of different OPT courses in anti‐NMDAR encephalitis. Methods The CHASE study, a multicenter prospective observational cohort study, enrolled patients with autoimmune encephalitis from October 2011 to March 2023. Patients were grouped based on oral prednisone tapering course: ≤3 months (Group ≤3 month), 3–6 months (Group 3–6 months, including 3 months), and >6 months (Group > 6 months). Kaplan–Meier plots were used to analyze time to relapse and time to total recovery within 2 years. Results Among 666 screened patients, 171 (median [IQR] age 27 [21.0–36.5] years, 55.0% female) met selection criteria. Responders at 3 months were prevalent in Group ≤3 months (OR 7.251 [95% CI 2.252 to 23.344] and Group 3–6 months (OR, 3.857 [95% CI 1.107 to 13.440] than in Group >6 months. Clinical Assessment Scale for Autoimmune Encephalitis (CASE) scores at 12 months were higher in Group >6 months than in Group ≤3 months and Group 3–6 months ( β , −2.329 [95% CI −3.784 to −.875]; β , −2.871 [95% CI −4.490, −1.253]). CASE seizures subscore was higher in Group >6 months than in Group 3–6 months ( β , −.452 [95% CI −.788 to −.116]). No significant difference in seizure freedom rates among the groups. Adverse events were higher in Group 3–6 months and Group >6 months than in Group ≤3 months (OR 6.045 [95% CI 2.352 to 15.538]; OR 6.782 [95% CI 1.911 to 24.073]). Significance Longer oral prednisone courses for adult patients with anti‐NMDAR encephalitis did not show superior effects compared to shorter courses in improving modified Rankin Scale (mRS) scores and CASE scores, reducing the risk of relapse within 2 years, or achieving seizure freedom. Instead, extended prednisone courses may lead to more side effects— particularly weight gain. This outcome recommends evaluating the possibility of shortening the duration of oral prednisone after a thorough patient assessment.