Effective treatment of severe COVID-19 patients with tocilizumab

Abstract

After analyzing the immune characteristics of patients with severe coronavirus disease 2019 (COVID-19), we have identified that pathogenic T cells and inflammatory monocytes with large amount of interleukin 6 secreting may incite the inflammatory storm, which may potentially be curbed through monoclonal antibody that targets the IL-6 pathways. Here, we aimed to assess the efficacy of tocilizumab in severe patients with COVID-19 and seek a therapeutic strategy. The patients diagnosed as severe or critical COVID-19 in The First Affiliated Hospital of University of Science and Technology of China (Anhui Provincial Hospital) and Anhui Fuyang Second People's Hospital were given tocilizumab in addition to routine therapy between 5 and 14 February 2020. The changes of clinical manifestations, computerized tomography (CT) scan image, and laboratory examinations were retrospectively analyzed. Fever returned to normal on the first day, and other symptoms improved remarkably within a few days. Within 5 d after tocilizumab, 15 of the 20 patients (75.0%) had lowered their oxygen intake, and 1 patient needed no oxygen therapy. CT scans manifested that the lung lesion opacity absorbed in 19 patients (90.5%). The percentage of lymphocytes in peripheral blood, which decreased in 85.0% of patients (17/20) before treatment (mean, 15.52 ± 8.89%), returned to normal in 52.6% of patients (10/19) on the fifth day after treatment. Abnormally elevated C-reactive protein decreased significantly in 84.2% of patients (16/19). No obvious adverse reactions were observed. All patients have been discharged on average 15.1 d after giving tocilizumab. Preliminary data show that tocilizumab, which improved the clinical outcome immediately in severe and critical COVID-19 patients, is an effective treatment to reduce mortality.

Keywords: COVID-19; SARS-CoV-2; cytokine storm; interleukin-6; tocilizumab.

Fig. 1.

Chest CT scans showed significant remission in both lungs in patients after the treatment with tocilizumab. (A–C) Computerized tomography (CT) showed plaque-like and ground glass opacities before the treatment with tocilizumab. (D–F) Chest CT showed diffuse infiltration in both lungs, but the lesions were clearly absorbed after the treatment with tocilizumab.

Fig. 2.

The values of CRP, body temperature, concentration of oxygen inhalation, and oxygen saturation before and after the treatment with tocilizumab for the 21 patients with COVID-19. (A) CRP decreased significantly after the treatment with tocilizumab and returned to normal in the majority of the patients. (B) The fever returned to normal in all 21 patients after tocilizumab. (C and D) Before the treatment, 20 patients needed oxygen therapy except 1 who refused. After tocilizumab, 15 patients had lowered their oxygen intake, and the oxygen saturation remained stable. Among them, one patient did not need further oxygen therapy on the third day. Therefore, the concentration of his oxygen inhalation during D3-D5 has marked as 21%, similar as oxygen content in normal air. (B–D) *P < 0.05, **P < 0.01, ***P < 0.005, ****P < 0.0001. D, day after tocilizumab; SpO2, percutaneous blood oxygen saturation.