BACKGROUND: Cognitive impairment is a well-recognized symptom of multiple sclerosis (MS) that can manifest early in the disease course. Deficits in cognitive function can have a major impact on daily life. However, cognitive decline is often under-examined in clinical trials and clinical practice due to lack of adequate data. The objective of this study was to examine the longitudinal effect of ocrelizumab vs interferon beta (IFNβ)-1a on cognitive impairment in 2 phase 3 studies in relapsing MS (RMS). METHODS: The pooled population of participants with RMS (n = 1656) from the OPERA I/II clinical trials received subcutaneous IFNβ-1a (44 μg; n = 829) 3 times weekly or intravenous ocrelizumab (600 mg; n = 827) every 24 weeks. Cognition was assessed with a Symbol Digit Modalities Test (SDMT), administered in written or oral form according to each site investigator's choice, that primarily measured cognitive processing speed at baseline and every 12 weeks until the end of the double-blind treatment (96 weeks). Treatment effects were investigated based on longitudinal linear models for the change from baseline in SDMT and Cox regression for the time to 12- or 24-week confirmed decline of ≥4 points. RESULTS: Among the participants with an SDMT assessment at baseline and ≥1 postbaseline time point (IFNβ-1a, n = 749; ocrelizumab, n = 766), ocrelizumab treatment was associated with a greater mean SDMT improvement over 96 weeks than IFNβ-1a treatment (5.4 [95 % CI, 4.4-6.5] vs 4.0 [95 % CI, 3.0-5.1]; adjusted mean difference, 1.4 [95 % CI, 0.05-2.72]; P = 0.042). The risk of a clinically meaningful SDMT decline (≥4 points) was lower for those treated with ocrelizumab for both ≥12 weeks (IFNβ-1a, 18.4 %; ocrelizumab, 12.7 %; hazard ratio, 0.63 [95 % CI, 0.47-0.85]; P = 0.003) and ≥24 weeks (IFNβ-1a, 12.9 %; ocrelizumab, 7.9 %; HR, 0.57 [95 % CI, 0.39-0.82]; P = 0.003). CONCLUSION: Ocrelizumab treatment resulted in better cognitive outcomes as measured by SDMT in participants with RMS compared with IFNβ-1a treatment. However, methodological limitations need to be considered when interpreting these data. CLINICALTRIALS: gov: NCT01247324, NCT01412333.

Brain and Mind Centre University of Sydney 94 Mallett Street Camperdown NSW 2050 Australia

Corinne Goldsmith Dickinson Center for Multiple Sclerosis at Icahn School of Medicine at Mount Sinai 5 E 98th St New York NY 10029 USA

Department of Neurology Heinrich Heine University Düsseldorf Moorenstraße 5 40225 Düsseldorf Germany

Department of Neurology Palacky University Olomouc Zdravotníku 248 7 779 00 Olomouc Czech Republic

F Hoffmann La Roche Ltd Grenzacherstrasse 124 4070 Basel Switzerland

Genentech Inc 1 DNA Way South San Francisco CA 94080 USA

Impulze GmbH Rämistrasse 50 8001 Zürich Switzerland

Jacobs School of Medicine and Biomedical Sciences University at Buffalo 955 Main St Buffalo NY 14203 USA

Providence Multiple Sclerosis Center 9135 SW Barnes Rd 461 Portland OR 97225 USA

University Hospital Basel University of Basel Universitätsspital CH Petersgraben 4 4031 Basel Switzerland

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