Background Ocrelizumab Phase III study safety findings in relapsing (OPERA I/II [NCT01247324/NCT01412333]) and primary progressive multiple sclerosis (ORATORIO [NCT01194570]) were reported; infections and serious infections are reported here. Methods: Ocrelizumab patients received 600 mg intravenously every 24 weeks for 96 weeks (OPERA I/II) or ≥120 weeks (ORATORIO; 2 × 300 mg infusions 14 days apart every 24 weeks). Controls received interferon beta-1a 44 µg thrice weekly (IFNβ−1a; OPERA I/II) or placebo (ORATORIO). Infections were classified by MedDRA system organ class/preferred term.

Results Non-serious infection rates in ocrelizumab-treated patients in OPERA were 58.4% (pooled analysis) and ORATORIO 69.8%; comparators were IFNβ−1a 52.4% and placebo 67.8%. Most infections were mild-to-moderate. Common infections (≥10% in either group) reported more in ocrelizumab treated patients were upper respiratory tract infections and either nasopharyngitis (OPERA) or influenza (ORATORIO);<1% of ocrelizumab-treated patients withdrew due to non-serious infections. Serious infections occurred in 1.3% (OPERA) and 6.2% (ORATORIO) of ocrelizumab-treated patients; comparators were IFNβ−1a 2.9% and placebo 5.9%. No infection-related deaths occurred in ocrelizumabtreated patients in OPERA; two deaths occurred in ORATORIO (aspiration pneumonia and pneumonia [unrelated per investigator, related per sponsor]). No opportunistic infections were reported.

Conclusion Serious infection rates with ocrelizumab were numerically lower than with IFNβ−1a and similar compared with placebo.