Comparative evaluation of tocilizumab and itolizumab for treatment of severe COVID-19 in India: a retrospective cohort study

Background: Itolizumab downregulates the synthesis of proinflammatory cytokines and adhesion molecules by inhibiting CD6 leading to lower levels of interferon-gamma, interleukin-6, and tumor necrotic factor-alpha and reduced T-cell infiltration at inflammatory sites. This study aims to compare the effects of tocilizumab and itolizumab in the management of severe coronavirus disease 2019 (COVID-19). Methods: The study population was adults (>18 years) with severe COVID-19 pneumonia admitted to the intensive care unit receiving either tocilizumab or itolizumab during their stay. The primary outcome was clinical improvement (CI), defined as a two-point reduction on a seven-point ordinal scale in the status of the patient from initiating the drug or live discharge. The secondary outcomes were time until CI, improvement in PO2/FiO(2) ratio, best PO2/FiO(2) ratio, need for mechanical ventilation after administration of study drugs, time to discharge, and survival days. Results: Of the 126 patients included in the study, 92 received tocilizumab and 34 received itolizumab. CI was seen in 46.7% and 61.7% of the patients in the tocilizumab and itolizumab groups, respectively and was not statistically significant (P=0.134). The PO2/FiO(2) ratio was significantly better with itolizumab compared to tocilizumab (median [interquartile range]: 315 [200-380] vs. 250 [150-350], P=0.043). The incidence of serious adverse events due to the study drugs was significantly higher with itolizumab compared to tocilizumab (14.7% vs. 3.3%, P=0.032). Conclusions: The CI with itolizumab is similar to tocilizumab. Better oxygenation can be achieved with itolizumab and it can be a substitute for tocilizumab in managing severe COVID-19.