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Anti-influenza hIVIG increases HAI antibody titers
Hyperimmune intravenous immunoglobulin treatment appeared to significantly increase hemagglutination inhibition antibody titer concentrations in patients with influenza, according to recent findings.
In the randomized, double blind pilot study, researchers evaluated 31 adults with laboratory-confirmed seasonal influenza at one of eight U.S. sites during 2013-2014. The patients were randomly assigned to standard of care (SOC) plus a 0.25 g/kg dose of anti-influenza hyperimmune intravenous immunoglobulin (Emergent Biosolutions; n = 16) or placebo.
Intravenous immunoglobulin (IVIG) infusions were administered over at least 2 hours, and blood samples were collected and measured for hemagglutination inhibition (HAI) antibody titers in each major strain of influenza A (H1N1 and H3N2) and B viruses. The measurements were taken before and after infusion on days 1, 3, 7 and 28; laboratory safety tests were conducted pre-infusion and after infusion at days 3, 7 and 28. The researchers used paired t tests to characterize the difference in log-transformed HAI antibody titers in the IVIG group.
The researchers wrote that all patients in the IVIG-arm infected with A/California/07/2009 AH1N1 pdm09 virus attained targeted HAI antibody titers; all patients infected with A/Texas/50/2012 H3N2 virus achieved HAI antibody targets; and 93.8% of those infected with B/Massachusetts/02/2012 virus met HAI antibody targets.
A significant difference in HAI antibody titer levels was observed between the IVIG vs. placebo groups in patients with A (H1N1) pdm09 during the first 3 days of follow-up. The ratio of geometric mean titers for IVIG vs. placebo was highest 1 hour after infusion (3.9; 95% CI, 2.3-6.7), followed by the first (3.1; 95% CI, 1.8-5.4) and third days (2; 95% CI, 1-4).
Three patients experienced grade 4 adverse events, including one patient who had three grade IV events and died from advanced cancer unrelated to the study. The two other patients each experienced one grade 4 event of unknown etiology.
“This trial is seeking to evaluate the efficacy and safety of anti-influenza hIVIG in patients hospitalized with severe influenza beginning with the 2014-2015 Northern Hemisphere influenza season,” the researchers wrote. “Due to the ongoing threat of antigenic drift, one major challenge of such a trial will be the need to keep the antibody specificity of the manufactured IVIG product contemporaneous with circulating virus subtypes throughout the projected course of the study over two or more influenza seasons.” – by Jen Byrne
Disclosure: Davey reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.