Clinical efficacy of tocilizumab treatment in severe and critical COVID-19 patients

BACKGROUND The main pathophysiological basis of coronavirus disease 2019 (COVID-19) causing respiratory failure is a cytokine storm and interleukin-6 (IL-6) is an important component of the COVID-19 cytokine storm. As a specific antagonist of IL-6, tocilizumab may block the cytokine storm of COVID-19. The Diagnosis and Treatment Guidelines of New Coronavirus Pneumonia (7(th)Edition) includes tocilizumab as a recommended drug for immunotherapy in severe and critical COVID-19 patients. However, the specific clinical efficacy of tocilizumab in the treatment of COVID-19 patients is worth studying. AIM To determine the clinical efficacy of tocilizumab in inhibiting the cytokine storm in COVID-19. METHODS In total, 19 severe and critical COVID-19 patients were enrolled in this study, and were treated with tocilizumab in Optical Valley Campus of Hubei Maternal and Child Health Care Hospital from February 20 to March 31, 2020. The imaging manifestations and clinical data before and after treatment were analyzed retrospectively, including routine peripheral venous blood tests, routine blood biochemical tests, coagulation test, C-reactive protein (CRP), IL-6, and arterial blood gas analysis. RESULTS Of the 19 patients in this group, 13 (68.4%) had significantly improved symptoms of COVID-19 (5 patients were discharged directly and 8 patients were transferred after improvement) following treatment. One case was invalid, 1 case was exacerbated, and 4 deaths (21.1%) were observed (all critical cases). The lymphocyte count, CRP, lactic acid, oxygenation index, fibrinogen (FIB) and IL-6 levels were significantly different in the improved group. CONCLUSION Tocilizumab treatment is effective against IL-6 in COVID-19 patients, but it does not completely inhibit the inflammation and cytokine storm in all patients with COVID-19.In the clinical treatment of COVID-19 patients, attention should be paid to the timing of drug administration and other adjuvant treatments.