Effect of ocrelizumab on rates of retinal atrophy in relapsing multiple sclerosis.

BACKGROUND: Ganglion cell + inner plexiform layer (GCIPL) atrophy reflects global neurodegeneration and disability in multiple sclerosis (MS). The effect of ocrelizumab, an anti-CD20 monoclonal antibody and highly-effective disease modifying therapy (DMT), on rates of GCIPL atrophy in people with MS remains understudied. OBJECTIVES: To assess if ocrelizumab attenuates retinal atrophy rates, particularly GCIPL atrophy, and change in clinical measures in people with relapsing MS (PwRMS), and how this compares to natalizumab (another highly-effective DMT), as well as the related anti-CD20 therapy rituximab. METHODS: PwRMS receiving ocrelizumab, natalizumab, or rituximab, untreated people with progressive MS (PwPMS), and healthy controls underwent Cirrus HD-OCT, 100% and 2.5%-contrast letter acuity (LA) assessments longitudinally. MS participants underwent Expanded Disability Status Scale (EDSS) assessments. Statistical analyses used linear mixed-effects regression models adjusting for age, sex, race, disease duration, optic neuritis history, and interval between DMT initiation and OCT monitoring; accounting for within-subject, inter-eye correlations. RESULTS: In ocrelizumab-treated PwRMS, GCIPL atrophy rate was -0.15 µm/year (SE = 0.03, p < 0.001, n = 88 [168 eyes]), similar to GCIPL atrophy in natalizumab- or rituximab-treated PwRMS, and healthy controls, although slower than in untreated PwPMS (-0.35 µm/year, SE = 0.04, p < 0.001, n = 40 [78 eyes]). EDSS and LA scores remained stable in ocrelizumab-treated PwRMS, and similar to natalizumab- or rituximab-treated PwRMS. CONCLUSION: GCIPL atrophy is attenuated and clinical function relatively stable in PwRMS treated with ocrelizumab.