Effects of adjunct treatment with intravenous Octagam on the course of severe COVID-19: results from a retrospective cohort study

<b><i>Objectives:</i></b> To evaluate the effect of adjunct treatment with Octagam, an intravenous immunoglobulin (IVIG) product, on clinical outcomes and biomarkers in critically ill COVID-19 patients. <b><i>Methods:</i></b> Data from a single center was analyzed retrospectively. Patients had received preliminary standard of intensive care (SIC) according to a local treatment algorithm, either alone or along with Octagam 5% at 30 g/day for 5 days. Both groups were compared regarding baseline characteristics, survival, and changes in inflammation markers. Imbalance in baseline APACHE II scores was addressed by propensity score matching. Otherwise, Kaplan-Meier and multiple logistic regression models were used. <b><i>Results:</i></b> Out of 93 patients, 51 had received Octagam and 42 had not. About 75% of patients were male and both groups had comparable body mass index and AB0 blood type distribution. Octagam-treated patients were younger (mean 65 ± 15 versus 71 ± 15 years, p = 0.066) and had slightly lower baseline disease scores (APACHE II: 20.6 versus 22.4, p = 0.281; SOFA: 5.0 versus 7.0, p = 0.006). Overall survival was 61% in the SIC + Octagam and 38% in the SIC only group (odds ratio: 2.2, 95% confidence interval: 0.9-5.4, p = 0.091 after controlling for baseline imbalances). Octagam significantly prolonged median survival time (68 versus 18 days, p = 0.014) and significantly reduced plasma levels of C-reactive protein (median change from baseline -71.5 versus -0.3 mg/L, p = 0.049). <b><i>Conclusion:</i></b> Clinically relevant benefits through adjunct Octagam treatment in COVID-19 need to be confirmed in a randomized, controlled trial.