Background and importance Tocilizumab is being used to treat severe SARS-CoV-2 pneumonia.

Aim and objectives To analyse the efficacy of tocilizumab in patients with severe SARS-CoV-2 pneumonia during the inflammatory phase of the disease.

Material and methods An observational retrospective study was conducted between 16 March and 22 April 2020, which included 75 patients (57 men, mean age 67.7 years) treated with tocilizumab. Criteria for severe pneumonia were: failure of at least one organ, oxygen saturation with ambient air <90% or respiratory rate ≥30 breaths per minute. Prognosis at admission was evaluated with the CURB-65 score. An analysis was performed with SPSS V.23.0. To evaluate efficacy, the variation in C reactive protein (CRP) and lymphocyte count (LC) was measured from the time before tocilizumab treatment until 5 days later, in all patients and separately in those who remained alive and those who died.

Results 75% of patients had a CURB-65 score ≤2 on admission. Mean time from onset of symptoms to treatment with tocilizumab was 11.6 days. 17 patients were admitted to the intensive care unit. Mean hospital stay was 19.7 days. During admission, all patients previously received lopinavir–ritonavir and hydroxychloroquine, 67 high dose corticosteroids, 6 baricitinib and 15 interferon-beta-1b. 19 patients (25%) died.

Mean CRP before tocilizumab treatment was 154.1 mg/L (95% CI 129.0 to 179.0) versus a mean of 15.2 mg/L (95% CI 8.6 to 21.4) 5 days later. In patients who remained alive, the mean CRP decreased from 163.4 mg/L (95% CI 134.5 to 192.3) to 13.1 mg/L (95% CI 8.9 to 17.3), and in those who died, it decreased from 117.6 mg/L (95% CI 69.9 to 165.2) to 23.2 mg/L (95% CI 0.0 to 52.0). Mean LC before tocilizumab treatment was 1080/μL (95% CI 360 to 1790) versus a mean LC of 1690/μL (95% CI 530 to 2860) 5 days later. In patients who remained alive, the mean LC increased from 1180/μL (95% CI 280 to 2080) to 1810/μL (95% CI 350 to 3270), and in those who died it increased from 680/μL (95% CI 550 to 810) to 1220/μL (95% CI 740 to 1700).

Conclusion and relevance In patients with severe SARS-CoV-2 pneumonia, we found a significant decrease in CRP and an increase in LC associated with treatment with tocilizumab in the inflammatory phase of the disease. Both variations were greater in patients who remained alive. LC prior to treatment with tocilizumab was lower in those who died than in living patients.

Conflict of interest No conflict of interest