Transient adverse events after REGN-CoV2 administration for mild COVID-19 patients and their potential predictive factors: a single center analysis

BackgroundREGN-COV2, a monoclonal antibody cocktail drug against the SARS-COV-2 virus, has proven to be effective in preventing the development of severe COVID-19 and is increasingly being administered in outpatient and home settings. Adverse events such as fever and decreased oxygen saturation may occur after administration of REGN-COV2, and although these symptoms are generally mild and transient, predicting the occurrence of these adverse events is useful in developing a monitoring plan for patients. MethodsWe performed a retrospective analysis of 76 patients who received REGN-CoV2 between August and September 2021. We collected information on fever, decreased oxygen saturation requiring oxygen supplementation, and other adverse events from medical records. Patients were divided into two subgroups: those who presented with fever or oxygen desaturation and those who did not, and underlying medical conditions and laboratory data were compared between each group. The parameters that exhibited significant differences were further tested using Fishers exact test to evaluate whether appropriate thresholds could be set to distinguish the incidence group from the non-incidence group. FindingsOf the 76 patients, 47 had fever of 38.5{degrees}C or higher within 24 hours after administration, and 27 of these patients had a body temperature of 37.5{degrees}C or lower before administration. Oxygen was required in 17 cases, 7 of which required oxygen more than 24 hours after administration of REGN-COV2, and additional treatment such as dexamethasone was given as the disease progressed to moderate. Among the parameters analyzed, lymphocyte count and IFN{lambda}3 showed significant differences between the fever and non-fever groups. This was also the case in the comparison excluding patients who had fever before administration. There was also a significant difference in ferritin and CRP between the oxygen required and non-required groups. In addition to IFN{lambda}3, ferritin, and CRP, there was a significant difference in LDH between the group that required additional treatment and the group that did not. When lymphocytes count <950/{micro}L was used to predict fever, the sensitivity and specificity were 55% and 79%, respectively, with odds ratio 4.746 (95% CI: 1.666 to 14.12, p=0.004) in contingency table analysis. Similarly, when IFN{lambda}3 >5.0 was used as the cutoff, sensitivity 72%, specificity 76%, odds ratio 8.220 (2.857 to 22.22; p<0.0001). InterpretationsTransient fever and decreased oxygen saturation are common adverse events after REGN-CoV2 administration, and their occurrence correlated with the severity factor of COVID-19 itself. Evaluation of these items at the time of administration is useful not only for predicting the severity of COVID-19 but also for the development of adverse events in patients receiving REGN-CoV2.