INSIGHT FLU005: An Anti–Influenza Virus Hyperimmune Intravenous Immunoglobulin Pilot Study

Hemagglutination inhibition (HAI) antibody responses to anti-influenza virus hyperimmune intravenous immunoglobulin (hIVIG) were characterized. Thirty-one patients with influenza during the 2013-2014 season were randomly assigned to receive 0.25 g/kg of hIVIG (n = 16) or placebo (n = 15). For hIVIG recipients, the ratio of geometric mean titers (1 hour after infusion/before infusion) was 4.00 (95% confidence interval [CI], 2.61-6.13) for 2009 pandemic influenza A(H1N1) and 1.76 (95% CI, 1.33-2.32) for influenza A(H3N2) and influenza B. Among patients with 2009 pandemic influenza A(H1N1), ratios for hIVIG (n = 9) versus placebo (n = 8) were higher 1 hour after infusion (3.9 [95% CI, 2.3-6.7]) and sustained through day 3 (2.0 [95% CI, 1.0-4.0]). hIVIG administration significantly increases HAI titer levels among patients with influenza, supporting the need to perform a clinical outcomes study.