Background
Tocilizumab blocks pro-inflammatory activity of interleukin-6 (IL-6), involved in pathogenesis of pneumonia the most frequent cause of death in COVID-19 patients.
Methods
A multicenter, single-arm, hypothesis-driven trial was planned, according to a phase 2 design, to study the effect of tocilizumab on lethality rates at 14 and 30 days (co-primary endpoints, a priori expected rates being 20 and 35%, respectively). A further prospective cohort of patients, consecutively enrolled after the first cohort was accomplished, was used as a secondary validation dataset. The two cohorts were evaluated jointly in an exploratory multivariable logistic regression model to assess prognostic variables on survival.
Results
In the primary intention-to-treat (ITT) phase 2 population, 180/301 (59.8%) subjects received tocilizumab, and 67 deaths were observed overall. Lethality rates were equal to 18.4% (97.5% CI: 13.6–24.0, P = 0.52) and 22.4% (97.5% CI: 17.2–28.3, P < 0.001) at 14 and 30 days, respectively. Lethality rates were lower in the validation dataset, that included 920 patients. No signal of specific drug toxicity was reported. In the exploratory multivariable logistic regression analysis, older age and lower PaO2/FiO2 ratio negatively affected survival, while the concurrent use of steroids was associated with greater survival. A statistically significant interaction was found between tocilizumab and respiratory support, suggesting that tocilizumab might be more effective in patients not requiring mechanical respiratory support at baseline.
Conclusions
Tocilizumab reduced lethality rate at 30 days compared with null hypothesis, without significant toxicity. Possibly, this effect could be limited to patients not requiring mechanical respiratory support at baseline.
Registration EudraCT (2020-001110-38); clinicaltrials.gov (NCT04317092).
Treatment of acute respiratory distress syndrome (ARDS) due to COVID-19 pneumonia (CARDS) represents a clinical challenge, requiring often invasive mechanical ventilation (IMV). Since the pathogenesis of CARDS it probably involves a direct viral attack to pulmonary and endothelium cells, and immune-mediated inflammation with dysfunctional coagulation, it was suggested to interfere with interleukin-6 (IL-6) activity by using the IL-6 receptor monoclonal antibody tocilizumab (TCZ). We reported the case of a 54-year-old 100 kg male COVID-19 patient (BMI 29) with severe respiratory insufficiency featuring dyspnea and hypoxia (SpO2 89% on room; PaO2 53 mmHg). Despite treatment with antiviral and non-invasive ventilation (NIV), after 24 h there was a progressive worsening of clinical conditions with higher fever (40 °C), increased dyspnea, and hypoxia (PaO2/FiO2 or P/F ratio of 150). The patient was at the limit to be sedated and intubated for IMV. He was treated with tocilizumab (8 mg/Kg i.v., single shot 800 mg) and NIV in the prone positioning. After only 96 h, the clinical, laboratory, and imaging findings showed incredible improvement. There was an important gain in oxygenation (P/F 300), a decrease of C-reactive protein values, and a decrease of the fever. Both the neutrophil-to-lymphocyte ratio (NLR) and the derived NLR ratio dropped down to 44%. Chest imaging confirmed the favorable response. This case suggested that for CARDS management efforts are needed for reducing its underlying inflammatory processes. Through a multiprofessional approach, the combination of IL-6-targeting therapies with calibrated ventilatory strategies may represent a winning strategy for improving outcomes.
In the absence of known cardio-pulmonary disease, BF is associated with statistically significant perturbations in gas exchange and alterations in the pattern of breathing including shortening of the inspiratory time.
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