Switching from Rituximab to Eculizumab in US Patients with Neuromyelitis Optica Spectrum Disorder: Impact on...

Neuromyelitis optica spectrum disorder (NMOSD), a rare autoimmune disease, affects the optic nerves and spinal cord. Rituximab is often used off-label to treat NMOSD; however, comparator-controlled trial data are limited. Eculizumab is approved for treatment of anti-aquaporin-4 antibody-positive (AQP4-Ab+) NMOSD. Outcomes data for patients who switch from rituximab to eculizumab are limited.

This retrospective study used claims data from the IQVIA PharMetrics^® Plus database (1/1/2015-3/31/2022). Patients aged ≥ 18 years with NMOSD treated with rituximab were identified and split into two groups: patients with an eculizumab claim after rituximab (switch group, n = 20) and patients without an eculizumab claim (control group, n = 525). Hospitalization rates and duration were assessed 6 months before and 6 months after the switch date (switch group) or reference date (1-year post-rituximab initiation; control group).

The percentage of patients hospitalized in the switch group decreased after transitioning to eculizumab (45.0% vs. 10.0%; p = 0.034) corresponding to a decreased mean number of hospitalizations per patient from 1.1 to 0.1 (p = 0.005). The percentage of patients hospitalized in the control group was similar before and after the reference date (10.1% vs. 9.3%; p = 0.755) corresponding to a mean number of hospitalizations per patient of 0.160 and 0.156 (p = 0.922), respectively. In the switch group, median (interquartile range [IQR]) hospitalization duration decreased from 8.5 (5.0-11.0) days before switching to eculizumab to 2.5 (2.2-2.8) days after switching (p < 0.001). Median (IQR) hospitalization duration in the control group was 4.0 (2.0-9.0) days before and 4.0 (2.0-6.0) days after the reference date.

Although the claims-based analysis and small patient numbers limit generalizability, we observed a reduction in hospitalizations number and length of stay in a cohort of patients with NMOSD who switched from rituximab to eculizumab.