Challenges in interpreting cytokine data in COVID-19 affect patient care and management.

Challenges in using cytokine data are limiting Coronavirus Disease 2019 (COVID-19) patient management and comparison among different disease contexts. We suggest mitigation strategies to improve the accuracy of cytokine data, as we learn from experience gained during the COVID-19 pandemic.

Cytokine Profiles Before and After Immune Modulation in Hospitalized Patients with COVID-19.

We describe the cytokine profiles of a large cohort of hospitalized patients with moderate to critical COVID-19, focusing on IL-6, sIL2R, and IL-10 levels before and after receiving immune modulating therapies, namely, tocilizumab and glucocorticoids. We also discuss the possible roles of sIL2R and IL-10 as markers of ongoing immune dysregulation after IL-6 inhibition. We performed a retrospective chart review of adult patients admitted to a tertiary care center with moderate to critical SARS-CoV-2 infection. Disease severity was based on maximum oxygen requirement during hospital stay to maintain SpO2 > 93% (moderate, 0-3 L NC; severe, 4-6 L NC or non-rebreather; critical, HFNC, NIPPV, or MV). All patients were treated using the institution's treatment algorithm, which included consideration of tocilizumab for severe and critical disease. The most common cytokine elevations among all patients included IL-6, sIL2R, IFN-γ, and IL-10; patients who received tocilizumab had higher incidence of IL-6 and sIL2R elevations. Pre-tocilizumab IL-6 levels increased with disease severity (p = .0151). Both IL-6 and sIL2R levels significantly increased after administration of tocilizumab in all severity groups; IL-10 levels decreased in severe (p = .0203), but not moderate or critical, patients after they received tocilizumab. Cluster analysis revealed association between higher admission IL-6, sIL2R, and CRP levels and disease severity. Mean IL-6, sIL2R, and D-dimer were associated with mortality, and tocilizumab-treated patients with elevated IL-6, IL-10, and D-dimer were more likely to also receive glucocorticoids. Accessible clinical cytokine panels may be useful for monitoring response to treatment in COVID-19. The increase in sIL2R post-tocilizumab, despite administration of glucocorticoids, may indicate the need for combination therapy in order to modulate more than one hyperinflammatory pathway in COVID-19. We also discuss the role of cytokines as potential biomarkers for use of adjunct glucocorticoid therapy.

Tocilizumab Treatment for Cytokine Release Syndrome in Hospitalized Patients With Coronavirus Disease 2019: Survival and Clinical Outcomes.

BACKGROUND: Tocilizumab, an IL-6 receptor antagonist, can be used to treat cytokine release syndrome (CRS), with observed improvements in a coronavirus disease 2019 (COVID-19) case series. RESEARCH QUESTION: The goal of this study was to determine if tocilizumab benefits patients hospitalized with COVID-19. STUDY DESIGN AND METHODS: This observational study of consecutive COVID-19 patients hospitalized between March 10, 2020, and March 31, 2020, and followed up through April 21, 2020, was conducted by chart review. Patients were treated with tocilizumab using an algorithm that targeted CRS. Survival and mechanical ventilation (MV) outcomes were reported for 14 days and stratified according to disease severity designated at admission (severe, ≥ 3 L supplemental oxygen to maintain oxygen saturation > 93%). For tocilizumab-treated patients, pre/post analyses of clinical response, biomarkers, and safety outcomes were assessed. Post hoc survival analyses were conducted for race/ethnicity. RESULTS: Among the 239 patients, median age was 64 years; 36% and 19% were black and Hispanic, respectively. Hospital census increased exponentially, yet MV census did not. Severe disease was associated with lower survival (78% vs 93%; P < .001), greater proportion requiring MV (44% vs 5%; P < .001), and longer median MV days (5.5 vs 1.0; P = .003). Tocilizumab-treated patients (n = 153 [64%]) comprised 90% of those with severe disease; 44% of patients with nonsevere disease received tocilizumab for evolving CRS. Tocilizumab-treated patients with severe disease had higher admission levels of high-sensitivity C-reactive protein (120 vs 71 mg/L; P < .001) and received tocilizumab sooner (2 vs 3 days; P < .001), but their survival was similar to that of patients with nonsevere disease (83% vs 91%; P = .11). For tocilizumab-treated patients requiring MV, survival was 75% (95% CI, 64-89). Following tocilizumab treatment, few adverse events occurred, and oxygenation and inflammatory biomarkers (eg, high-sensitivity C-reactive protein, IL-6) improved; however, D-dimer and soluble IL-2 receptor (also termed CD25) levels increased significantly. Survival in black and Hispanic patients, after controlling for age, was significantly higher than in white patients (log-rank test, P = .002). INTERPRETATION: A treatment algorithm that included tocilizumab to target CRS may influence MV and survival outcomes. In tocilizumab-treated patients, oxygenation and inflammatory biomarkers improved, with higher than expected survival. Randomized trials must confirm these findings.

Overview on the use of IL-6 agents in the treatment of patients with cytokine release syndrome (CRS) and pneumonitis related to COVID-19 disease.

INTRODUCTION: A novel coronavirus pneumonia (COVID-19) has caused significant life loss and healthcare burden globally. COVID-19 is known to cause a cytokine release syndrome (CRS) like response, and interleukin-6 (IL-6) is one of the cytokines involved. Clinicians are using IL-6 inhibitors to CRS, and researchers are investigating the use of IL-6 inhibitors, namely tocilizumab, sarilumab, siltuximab, in COVID-19 management. AREAS COVERED: In this article, we will discuss the pharmacology of these three inhibitors and summarize available clinical data via literature search on PubMed with keywords of tocilizumab, sarilumab, siltuximab, and COVID-19. While awaiting more data from randomized clinical trials on these drugs, observational studies and clinical reports have demonstrated IL-6 inhibitors showed some benefits in improving clinical outcome and a well-tolerated safety profile. EXPERT OPINION: There is a role for suppressing the immune response with IL-6 inhibitors that will continue to require investigation. These agents are available and have demonstrated a mild safety profile. There may be advantages to a targeted approach to suppressing the hyperinflammatory state of the disease. Timing, the long-term effects, and what cocktail of medications demonstrates the strongest outcomes are all important considerations as IL-6 inhibitors continue to be evaluated in this global pandemic.