Tocilizumab for patients with severe COVID-19: a retrospective, multi-center study

Abstract

Background: Tocilizumab, an inhibitor of the interleukin-6 receptor, may decrease the inflammatory response and control the symptoms of severe coronavirus disease 2019 (COVID-19), but the evidence is scarce.

Methods: This retrospective study included patients with severe COVID-19 requiring oxygen therapy who received tocilizumab in seven centers across Poland. We assessed on-treatment changes in clinical status and inflammatory markers.

Results: Twenty-eight patients were included (19 male), with a mean age of 61.7 ± 12.4 years. The mean time from symptom onset to the first tocilizumab dose was 10.5 ± 5.7 days. Clinical status improved within 24 hours in 11 (39%) patients, within one week in 23 (82%) patients, and within two weeks in 25 (89%); one (4%) patient showed no change and two (7%) patients died. Sixteen patients (57%) no longer needed oxygen therapy within a week (p < 0.001). The serum concentrations of C-reactive protein, procalcitonin, and fibrinogen decreased significantly (p ≤ 0.001). Lung changes improved in 21 (84%) patients within two weeks of treatment; 19 had minimal or no changes upon final examination.

Conclusions: Tocilizumab can control the symptoms of severe COVID-19 by reducing the inflammatory response and rapidly improves the clinical status in most patients.

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

Figure 1.

Oxygen saturation before and after the first tocilizumab dose in patients with severe COVID-19. Middle bar shows median; upper and lower bars show interquartile range.

Figure 2.

A semi-objective scale for assessing outcomes after treatment based on the baseline level of oxygen saturation (<90% vs. ? 90%). Following tocilizumab treatment, the outcomes included: mechanical ventilation and death, mechanical ventilation and survival, no mechanical ventilation and clinical improvement after 24 hours, and no mechanical ventilation and clinical improvement or within 24 hours.

Figure 3.

The proportion of patients showing varying degrees of lung changes (ceased, minimal, regression, or active) on repeated chest CT and/or X-ray images before (baseline) and after treatment with tocilizumab.

Figure 4.

Serum IL-6 concentrations before and after the first tocilizumab dose in patients with COVID-19. Middle bar shows median; upper and lower bars show the interquartile range.

Figure 5.

The proportion of patients who showed rapid (<24 hours) or slow (>24 hours) improvement or death following tocilizumab treatment depending on the number of comorbidities.