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Abstract
Growing clinical evidence has implicated complement as a pivotal driver of COVID-19 immunopathology. Deregulated complement activation may fuel cytokine-driven hyper-inflammation, thrombotic microangiopathy and NET-driven immunothrombosis, thereby leading to multi-organ failure. Complement therapeutics have gained traction as candidate drugs for countering the detrimental consequences of SARS-CoV-2 infection. Whether blockade of terminal complement effectors (C5, C5a, or C5aR1) may elicit similar outcomes to upstream intervention at the level of C3 remains debated. Here we compare the efficacy of the C5-targeting monoclonal antibody eculizumab with that of the compstatin-based C3-targeted drug candidate AMY-101 in small independent cohorts of severe COVID-19 patients. Our exploratory study indicates that therapeutic complement inhibition abrogates COVID-19 hyper-inflammation. Both C3 and C5 inhibitors elicit a robust anti-inflammatory response, reflected by a steep decline in C-reactive protein and IL-6 levels, marked lung function improvement, and resolution of SARS-CoV-2-associated acute respiratory distress syndrome (ARDS). C3 inhibition afforded broader therapeutic control in COVID-19 patients by attenuating both C3a and sC5b-9 generation and preventing FB consumption. This broader inhibitory profile was associated with a more robust decline of neutrophil counts, attenuated neutrophil extracellular trap (NET) release, faster serum LDH decline, and more prominent lymphocyte recovery. These early clinical results offer important insights into the differential mechanistic basis and underlying biology of C3 and C5 inhibition in COVID-19 and point to a broader pathogenic involvement of C3-mediated pathways in thromboinflammation. They also support the evaluation of these complement-targeting agents as COVID-19 therapeutics in large prospective trials.
Declaration of Competing Interest JDL is the founder of Amyndas Pharmaceuticals which develops complement inhibitors for therapeutic purposes, and inventor of patents that describe the therapeutic use of complement inhibitors, some of which are developed by Amyndas. JDL is also the inventor of the compstatin technology licensed to Apellis Pharmaceuticals (i.e., 4(1MeW)7 W/POT-4/APL-1 and PEGylated derivatives such as APL-2/pegcetacoplan and APL-9). JDL has received consulting fees from Achillion, Baxter, LipimetiX, Ra Pharma, Sanofi, and Viropharma. A.M.R. has received research support from Alexion Pharmaceuticals, Novartis, Alnylam and Ra Pharma and lecture fees from Alexion, Novartis, Pfizer and Apellis, and served as member of advisory–investigator boards for Alexion, Roche, Achillion, Novartis, Apellis and Samsung, and as a consultant for Amyndas. B.N. is a shareholder and consultant in Tikomed and iCoat Medica. M.H.-L. holds a patent on compositions of matter and methods for the diagnosis and treatment of sepsis by C5a inhibitory strategies licensed to InflaRx. R.T.C. acted as a speaker for Alexion Pharma Brazil. The other authors declare no competing interests.
Figures
Fig. 1
Markers of inflammation and tissue…
Fig. 1
Markers of inflammation and tissue injury in severe COVID-19 patients treated with C3… Fig. 1 Markers of inflammation and tissue injury in severe COVID-19 patients treated with C3 and C5 inhibitors. Graphs on the left column (panels A, B) represent the longitudinal change of inflammatory and tissue injury-related biomarkers in all COVID-19 patients dosed with the C3 (AMY-101) or C5-targeted inhibitor (eculizumab). These graphs include the three mechanically ventilated Ecu-patients (Ecu-patients No 1, 3, 9). To normalize for disease severity and exclude potential confounding factors from our analysis, the graphs on the right column represent the differential change of these markers in the non-ventilated patients of both cohorts from baseline to days 6–7. Panel A, Change of CRP levels in both patient cohorts; CRP values are expressed as fold change over the upper normal limit of each patient cohort. Panel B, Change of LDH levels in both patient cohorts; LDH values are expressed as fold change over the upper normal limit of each patient cohort. Panel C shows the consistent decrease of serum IL-6 levels in both patient cohorts. The plots illustrating the dynamic profiles of all biomarkers and all individual data points per each patient group are colour-coded (orange: AMY-101-treated, dark blue: Eculizumab-treated). Arrows indicate the time of dosing for eculizumab. * denotes the upper normal limit of biomarkers, ** denotes the lower normal limit. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 2
Blood cell monitoring during therapeutic…
Fig. 2
Blood cell monitoring during therapeutic complement inhibition in severe COVID-19 . Graphs on… Fig. 2 Blood cell monitoring during therapeutic complement inhibition in severe COVID-19. Graphs on the left column (panels A, B and C) represent the longitudinal change of blood cell counts in all COVID-19 patients dosed with the C3 (AMY-101) or C5-targeted inhibitor (eculizumab). These graphs also include the three mechanically ventilated Ecu-patients (Ecu-patients No 1, 3, 9). To normalize for disease severity and exclude potential confounding factors from our analysis, the graphs on the right column represent the differential change of these cell counts in the non-ventilated patients of both cohorts from baseline to days 7 or 8 after the start of drug dosing. Panel A, Change of peripheral blood neutrophil numbers in both patient cohorts; neutrophil numbers are expressed as absolute neutrophil counts (ANC, cellsx10 [9]/L). Panel B, Change of peripheral blood lymphocyte numbers in both patient cohorts; lymphocyte numbers are expressed as absolute lymphocyte counts (ALC, cellsx10 [9]/L). The dotted line represents the upper normal limit of lymphocyte counts in the circulation of healthy individuals. Panel C shows the longitudinal change of platelet counts in both patient cohorts. The plots illustrating the dynamic profiles of all biomarkers and all individual data points per each patient group are colour-coded (orange: AMY-101-treated, dark blue: Eculizumab-treated). * denotes the upper normal limit of blood counts; arrows indicate the time of dosing for eculizumab. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 3
C3 inhibition attenuates NET release…
Fig. 3
C3 inhibition attenuates NET release (NETosis) in COVID-19 patients. NET levels were measured… Fig. 3 C3 inhibition attenuates NET release (NETosis) in COVID-19 patients. NET levels were measured by an MPO/DNA complex ELISA in plasma samples collected from patients dosed with either AMY-101(orange-coloured symbols) or eculizumab (dark blue coloured symbols). (Panel A): The graph depicts the change of plasma NET levels over the course of treatment (days 0–2-7) in both patient cohorts, including the three ecu-treated patients who were mechanically ventilated. (Panel B): The graph depicts the change of NET levels in the plasma of all non-intubated COVID-19 patients. NET levels are expressed in arbitrary units (AU). Individual bars represent changes expressed as mean values ±SD. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 4
Clinical improvement of lung respiratory…
Fig. 4
Clinical improvement of lung respiratory function and resolution of SARS-C0V-2 associated ARDS .… Fig. 4 Clinical improvement of lung respiratory function and resolution of SARS-C0V-2 associated ARDS. Improvement of lung function in both patient cohorts was monitored as a function of the need for oxygen supplementation (expressed as % FiO2; % pf Fraction of Inspired Oxygen in Ventimask). The left graph represents the fraction of patients within each group that were weaned off oxygen support (by breathing in ambient air conditions, or 21% FiO2). Bars denote the baseline FiO2 values and corresponding values at patient discharge. The right graph illustrates the average time (in days) required for each patient to achieve disengagement from oxygen support (expressed as ‘time to no O2 support’). Individual data points and bars are colour-coded according to treatment (Eculizumab, dark blue; AMY-101, orange). Changes are expressed as mean %FiO2 values ±SD. Abbreviations: ns, not statistically significant; * denotes p < 0.05. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 5
In vivo biological efficacy of…
Fig. 5
In vivo biological efficacy of C3 vs C5 inhibition in COVID-19 - biomarkers…
Fig. 5 In vivo biological efficacy of C3 vs C5 inhibition in COVID-19 - biomarkers of complement activity (Panel A): Plasma C3a levels, as a marker of ongoing C3 activation, in patients treated with AMY-101 or eculizumab on days 0 (baseline), 2 and 7 following initiation of treatment. C3a values were quantified in EDTA-plasma samples by ELISA. Panel B: Plasma levels of sC5b-9 complexes, as a measure of ongoing terminal pathway activity (C5 activation) in patients treated with AMY-101 or eculizumab. Values for each patient are expressed as fold change over baseline (day 0). Panel C: Profiles of AP activity following C3 and C5 inhibition in COVID-19 patients. % AP activity was expressed as the % hemolytic activity of patient sera dosed with each inhibitor using ex vivo AP-mediated complement hemolytic assays (APH50). Panel D: Plasma levels of factor B (FB) in both patient cohorts during treatment with complement inhibitors (days 0–2-7). Total FB was measured in patient plasma by nephelometry using an IMMAGE 800 protein chemistry analyzer. Statistical analysis and comparisons within each group were performed with unpaired, two-tailed student's t-test; ** denotes p < 0.002. See this image and copyright information in PMC
Comment in
Curb complement to cure COVID-19. Satyam A, Tsokos GC.Satyam A, et al.Clin Immunol. 2020 Dec;221:108603. doi: 10.1016/j.clim.2020.108603. Epub 2020 Oct 3.Clin Immunol. 2020.PMID: 33022386Free PMC article.No abstract available.
Commentary on "Complement C3 vs C5 inhibition in severe COVID-19: Early clinical findings reveal differential biological efficacy" by D.C. Mastellos et al. de Miranda Santos IKF, de Barros Cardoso CR.de Miranda Santos IKF, et al.Clin Immunol. 2021 Jan;222:108618. doi: 10.1016/j.clim.2020.108618. Epub 2020 Oct 27.Clin Immunol. 2021.PMID: 33127564Free PMC article.No abstract available.
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