Heterogeneity of treatment effect of interferon-β1b and lopinavir-ritonavir in patients with Middle East respiratory syndrome by cytokine levels

Abstract

Animal and human data indicate variable effects of interferons in treating coronavirus infections according to inflammatory status and timing of therapy. In this sub-study of the MIRACLE trial (MERS-CoV Infection Treated with a Combination of Lopinavir-Ritonavir and Interferon β-1b), we evaluated the heterogeneity of treatment effect of interferon-β1b and lopinavir-ritonavir versus placebo among hospitalized patients with MERS on 90-day mortality, according to cytokine levels and timing of therapy. We measured plasma levels of 17 cytokines at enrollment and tested the treatment effect on 90-day mortality according to cytokine levels (higher versus lower levels using the upper tertile (67%) as a cutoff point) and time to treatment (≤ 7 days versus > 7 days of symptom onset) using interaction tests. Among 70 included patients, 32 received interferon-β1b and lopinavir-ritonavir and 38 received placebo. Interferon-β1b and lopinavir-ritonavir reduced mortality in patients with lower IL-2, IL-8 and IL-13 plasma concentrations but not in patients with higher levels (p-value for interaction = 0.09, 0.07, and 0.05, respectively) and with early but not late therapy (p = 0.002). There was no statistically significant heterogeneity of treatment effect according to other cytokine levels. Further work is needed to evaluate whether the assessment of inflammatory status can help in identifying patients with MERS who may benefit from interferon-β1b and lopinavir-ritonavir. Trial registration: This is a sub-study of the MIRACLE trial (ClinicalTrials.gov number, NCT02845843).

Figure 1

Serial measurements of selected plasma cytokine concentrations in patients treated with interferon-β1b and lopinavir–ritonavir, patients treated with placebo and healthy control. All cytokine levels were calculated based on mean fluorescent intensity and reported in pg/mL. We compared serial cytokine levels between patients treated with interferon-β1b and lopinavir–ritonavir and patients treated with placebo using a mixed linear model. We compared D1 values in both groups with those of healthy control using Mann–Whitney U test. G-CSF: granulocyte-colony stimulating factor; GM-CSF: granulocyte–macrophage colony-stimulating factor; IFN: interferon; IL: interleukin.

Figure 2

Kaplan–Meier time-to-event curves for mortality for patients with Middle East Respiratory Syndrome treated with interferon-β1b and lopinavir–ritonavir or placebo categorized into two subgroups of higher and lower levels of each of selected cytokines using the upper tertile (67%) as a cutoff point. Each cytokine is presented into two graphs based on the high (left panel) and low (right panel) levels at day 0. The number of patients at risk in treatment and placebo groups are presented. IL: interleukin.

Figure 3

Forest plot demonstrating the association of interferon-β1b and lopinavir–ritonavir treatment on 90-day mortality in patients with Middle East respiratory syndrome categorized into two subgroups of early and late treatment and according to higher and lower levels of each of the cytokines using the upper tertile (67%) as a cutoff point. The results are displayed as relative risks and 95% confidence intervals (CI), and p-values. Additionally, p-values for the interactions are reported. Plasma cytokine concentrations are expressed in pg/ml. There was heterogeneity of treatment effect on 90-day-mortality according to the level of IL-2, IL-8 and IL-13 as demonstrated by testing for interaction (p-value for interaction = 0.09, 0.07, and 0.05, respectively) while the interaction was were not significant for other cytokines (p > 0.1). G-CSF: granulocyte-colony stimulating factor; GM-CSF: granulocyte–macrophage colony-stimulating factor; IFN: interferon; IL: interleukin; MCP: Monocyte chemo-attractant protein; MIP: Macrophage inflammatory protein; TNF: tumor necrosis factor.