033 Ocrelizumab: serum Ig levels and serious infections

BackgroundAn apparent association between decreased Ig levels and serious infections (SIs) was pre- viously reported. Here, we characterised the temporal evolution of Ig levels and risk of SIs by baseline Ig quartile over 6 years in OPERA I/II (NCT01247324/NCT01412333), ORATORIO (NCT01194570), and their open-label extensions.MethodsSerum Ig levels were measured ≥24 weeks. Baseline IgG/IgM/IgA quartiles (g/L) were determined; Q1 represents the lowest quartile. Changes in Ig levels and SI rates by baseline quartiles were assessed.ResultsOver 6 years, mean change in IgG levels, g/L (% change) per year by quartile were: Q1, -0.24 (-2.9%); Q2, -0.32 (-3.2%); Q3, -0.40 (-3.6%); Q4, -0.40 (-3.0%) in OPERA, and Q1, -0.23 (-2.9%); Q2, -0.28 (-2.9%);Q3 -0.35 (-3.1%); Q4, -0.51 (-3.8%) in ORATORIO. SI rates/100PY (95% CI) were: Q1, 1.63 (0.95–2.61); Q2, 1.55(0.90–2.48); Q3, 1.51 (0.86–2.45); Q4, 1.11 (0.57–1.94) in OPERA, and Q1, 4.04 (2.66–5.87); Q2, 3.81 (2.46–5.62); Q3, 5.39 (3.76–7.50); Q4, 2.17 (1.22–3.59) in ORATORIO. Changes in IgM/IgA will also be presented.ConclusionsPatients with lower baseline IgG demonstrated less absolute IgG decline, but similar per- centage decline, versus patients with higher baseline IgG. SI rates were low, and similar across quartiles.k.schmierer@qmul.ac.uk