Intravenous immunoglobulin treatment for steroid-resistant optic neuritis: a multicenter, double-blind, randomized, controlled phase III study

Purpose To evaluate the efficacy and safety of intravenous “freeze-dried sulfonated human normal immunoglobulin (GGS)” in patients with steroid-resistant optic neuritis (ON). Study design Multicenter, prospective, double-blind, parallel-group, randomized controlled trial. Methods Patients with steroid-resistant acute ON were randomly assigned to receive either intravenous GGS (GGS group) or intravenous methylprednisolone (steroid pulse [SP] group). Visual acuity (logarithm of the minimum angle of resolution [logMAR]), mean deviation (MD) value of the Humphrey Field Analyzer, and critical flicker fusion frequency were measured as efficacy endpoints; adverse events (AEs) were assessed as the safety endpoint. Results Thirty-two patients (16 patients/group) received the study drugs. The primary endpoint, change in logMAR at week 2 compared to baseline, showed no statistically significant intergroup difference. However, compared with the SP group, change in the GGS group was increasingly indicative of visual improvement, with least squares mean difference of > 0.3 logMAR. On post-hoc analyses, the percentage of patients in the GGS and SP groups with improvement by ≥ 0.3 logMAR at week 2 were 75.0% and 31.3%, respectively. Changes in MD values at week 2 compared to baseline were 9.258 ± 8.296 (mean ± standard deviation) dB and 3.175 ± 6.167 dB in the GGS and SP groups, respectively. These results showed statistically significant intergroup differences (visual acuity improvement, P = 0.032; change in MD values, P = 0.030). No clinically significant AEs were observed. Conclusion Our results suggest that intravenous immunoglobulin could be a safe and efficacious therapeutic option for prompt treatment of steroid-resistant acute ON. Trial registration: JapicCTI-132080.