Does Adding hIVIG to Standard of Care for Influenza Benefit Patients?

Anti-influenza hyperimmune intravenous immunoglobulin (hIVIG) is not superior to placebo when added to standard care for adults with severe influenza, according to study findings.

To reach this conclusion, the researchers conducted a trial in 45 hospitals across 9 countries over 5 influenza seasons, from 2013 to 2018.

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Individuals aged 18 years or older who were hospitalized with laboratory-confirmed influenza A or B infection were randomly assigned to receive either a single 500-mL infusion of high-titer hIVIG (0.25 g/kg bodyweight, 24.75 g maximum) or saline placebo, in addition to standard care.

In all, 168 participants were randomly assigned to the hIVIG group and 161 were randomly assigned to the placebo group. Ultimately, 308 participants were included in the primary analysis.

At day 7, the researchers assessed for the primary endpoint, which was a 6-category ordinal outcome of clinical status that ranged in severity from mortality to resumption of normal activities after discharge. 

The adjusted odds ratio (OR) of hIVIG vs placebo for the primary endpoint was 1.25. Meanwhile, subgroup analyses for the primary outcome showed that the OR for patients with influenza A was 0.94 and for those with influenza B was 3.19. 

“hIVIG treatment produced a robust rise in hemagglutination inhibition titers against influenza A as well as smaller rises in influenza B titers,” the authors wrote.

Through 28 days of follow-up, 30% of participants in each group had the composite safety outcome of death, a serious adverse event, or a grade 3 or 4 adverse event.

“When administered alongside standard care (most commonly oseltamivir), hIVIG was not superior to placebo for adults hospitalized with influenza infection,” the researchers concluded. 

“By contrast with our prespecified subgroup hypothesis that hIVIG would result in more favorable responses in patients with influenza A than B, we found the opposite effect. The clinical benefit of hIVIG for patients with influenza B is supported by antibody affinity analyses, but confirmation is warranted.”

—Colleen Murphy

Reference:

Davey RT Jr, Fernández-Cruz E, Markowitz N, et al; INSIGHT FLU-IVIG Study Group. Anti-influenza hyperimmune intravenous immunoglobulin for adults with influenza A or B infection (FLU-IVIG): a double-blind, randomised, placebo-controlled trial. Lancet Respir Med. 2019;7(11):951-963. doi:10.1016/S2213-2600(19)30253-X.