Effective treatment of severe COVID-19 patients with tocilizumab
Main result
The 21 patients included in the study received a single dose of Tocilizumab of 4-8mg/Kg (recommended dose 400-800 mg). The treatment protocol included a second administration in case of fever within 12 hours of the first dose (maximum cumulative dose = two administrations).
Results
Body Temperature: After one day of treatment with Tocilizumab, all patients returned to normal body temperature. No patients developed a fever afterward.
Oxygen saturation (SpO2): 15/20 (75.0%) patients have seen their need for oxygen therapy reduced after 5 days of Tocilizumab. Of 3 patients requiring mechanical ventilation, 1 patient switched to non-invasive ventilation after 1 day, 1 patient was extubated at 5 days and the third at 11 days.
Lymphocytes: Before treatment, 85% (17/20, mean: 15.52±8.89%) of patients had reduced lymphocyte values. After treatment, 52.6% (10/19, mean: 22.62±13.48%) of patients displayed normal lymphocyte values and only 10.5% (2/19, mean: 5.25±2.11x10*9/L) of patients showed low lymphocyte counts 5 days after administration.
C-reactive protein: Prior to treatment, CRP was elevated in 20 patients (mean: 75.05±66.80 mg/L). Values returned to normal in 84.2% (16/19, mean: 2.72±3.60 mg/L) of patients 5 days after treatment.
IL-6: All patients had elevated IL-6 values (18 patients tested by electrochemical luminescence had mean values of 153.44±296.63 pg/mL, for the three patients tested by fluorescence method, values of 6.95%, 7.40%, and 7.72%). There was no decrease in IL-6 values in the days following treatment in any patient, which might be explained by the fact that the IL-6 receptors were linked by Tocilizumab.
CT scan: All 21 patients had abnormalities in chest CT; after treatment, 90.5% (19/21) of patients had reduced lung damage.
During treatment, no adverse reactions were detected and no pulmonary superinfection was reported.
Takeaways
The study shows that in COVID-19 patients with severe and very severe manifestations, treatment with Tocilizumab allows a return to normal body temperature, restores correct lymphocyte and PCR values (indicators of severity for the pathology), allows improvement of lung lesions.
The study has a strong limitation of being an observational study, with a very small sample size (n=21). Randomized controlled trials studying the mechanisms of IL-6 in the pathogenesis of COVID-19 will be necessary.
Strength of evidence Weak
Weak:
1) Retrospective observational study
2) Small sample size (n=21)
Objectives
Method
Chinese retrospective observational study.
Study conducted on 21 patients (7 included in Fist Affiliated Hospital of University of Science and Technology and 14 included in Anhui Fuyang Second People Hospital, China) treated with Tocilizumab between February 5 and 14, 2020.
The study involved COVID-19 patients with severe symptoms (FR≥30/min, SpO2≤ 93%, PaO2/FiO2≤ 300mmHg), and very severe symptoms (respiratory failure requiring mechanical ventilation, shock, multi-organ failure).
Interleukin-6 was measured by electrochemical luminescence method for 18 patients and by fluorescence-activated cell sorting analysis for 3 patients (baseline IL-6 value < 7 pg/mL).
All patients were previously treated for one week with Lopinavir/Ritonavir (200/50mg, 2 times/D), IFN-alpha (5 million U, 2 times/D), Ribavirin (500mg, 1-3 times/D), glucocorticoids but did not respond to treatment with fever, hypoxemia and worsening of radiological images.
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