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.
Subject(s)
Betacoronavirus/pathogenicity , Complement C3/antagonists & inhibitors , Complement C5/antagonists & inhibitors , Complement Inactivating Agents/therapeutic use , Coronavirus Infections/drug therapy , Immunologic Factors/therapeutic use , Pneumonia, Viral/drug therapy , Respiratory Distress Syndrome/drug therapy , Antibodies, Monoclonal, Humanized/therapeutic use , Biomarkers/blood , C-Reactive Protein/metabolism , COVID-19 , Cohort Studies , Complement Activation/drug effects , Complement C3/genetics , Complement C3/immunology , Complement C5/genetics , Complement C5/immunology , Coronavirus Infections/complications , Coronavirus Infections/immunology , Coronavirus Infections/virology , Extracellular Traps/drug effects , Female , Gene Expression , Humans , Interleukin-6/metabolism , Male , Middle Aged , Neutrophils/drug effects , Neutrophils/immunology , Neutrophils/virology , Pandemics , Peptides, Cyclic/therapeutic use , Pneumonia, Viral/complications , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Respiratory Distress Syndrome/complications , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2 , Severity of Illness IndexABSTRACT
The complement system plays a major role in human immunity, but its abnormal activation can have severe pathological impacts. By mimicking a natural mechanism of complement regulation, the small peptide compstatin has proven to be a very promising complement inhibitor. Over the years, several compstatin analogs have been created, with improved inhibitory potency. A recent analog is being developed as a candidate drug against several pathological conditions, including COVID-19. However, the reasons behind its higher potency and increased binding affinity to complement proteins are not fully clear. This computational study highlights the mechanistic properties of several compstatin analogs, thus complementing previous experimental studies. We perform molecular dynamics simulations involving six analogs alone in solution and two complexes with compstatin bound to complement component 3. These simulations reveal that all the analogs we consider, except the original compstatin, naturally adopt a pre-bound conformation in solution. Interestingly, this set of analogs adopting a pre-bound conformation includes analogs that were not known to benefit from this behavior. We also show that the most recent compstatin analog (among those we consider) forms a stronger hydrogen bond network with its complement receptor than an earlier analog.
Subject(s)
Antiviral Agents/chemistry , Complement C3/antagonists & inhibitors , Peptides, Cyclic/chemistry , Peptides, Cyclic/metabolism , Antiviral Agents/metabolism , COVID-19 , Complement C3/metabolism , Coronavirus Infections/drug therapy , Humans , Hydrogen Bonding , Molecular Dynamics Simulation , Pandemics , Pneumonia, Viral/drug therapy , Structure-Activity RelationshipSubject(s)
Antigen-Antibody Complex/biosynthesis , Betacoronavirus/pathogenicity , Coronavirus Infections/immunology , Cytokine Release Syndrome/immunology , Immune Complex Diseases/immunology , Pneumonia, Viral/immunology , Severe Acute Respiratory Syndrome/immunology , Vasculitis/immunology , Antibodies, Viral/biosynthesis , Antigen-Antibody Complex/drug effects , Betacoronavirus/immunology , Blood Vessels/drug effects , Blood Vessels/immunology , Blood Vessels/pathology , Blood Vessels/virology , COVID-19 , Complement C3/antagonists & inhibitors , Complement C3/biosynthesis , Complement Inactivating Agents/therapeutic use , Coronavirus Infections/complications , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Cytokine Release Syndrome/complications , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/virology , Humans , Immune Complex Diseases/complications , Immune Complex Diseases/drug therapy , Immune Complex Diseases/virology , Immunity, Humoral/drug effects , Interleukin 1 Receptor Antagonist Protein/therapeutic use , Interleukin-6/antagonists & inhibitors , Interleukin-6/biosynthesis , Pandemics , Pneumonia, Viral/complications , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Receptors, Interleukin-1/antagonists & inhibitors , Receptors, Interleukin-1/biosynthesis , SARS-CoV-2 , Severe Acute Respiratory Syndrome/complications , Severe Acute Respiratory Syndrome/drug therapy , Severe Acute Respiratory Syndrome/virology , Severity of Illness Index , Vasculitis/complications , Vasculitis/drug therapy , Vasculitis/virologyABSTRACT
Acute respiratory distress syndrome (ARDS) is a devastating clinical manifestation of COVID-19 pneumonia and is mainly based on an immune-driven pathology. Mounting evidence suggests that COVID-19 is fueled by a maladaptive host inflammatory response that involves excessive activation of innate immune pathways. While a "cytokine storm" involving IL-6 and other cytokines has been documented, complement C3 activation has been implicated as an initial effector mechanism that exacerbates lung injury in preclinical models of SARS-CoV infection. C3-targeted intervention may provide broader therapeutic control of complement-mediated inflammatory damage in COVID-19 patients. Herein, we report the clinical course of a patient with severe ARDS due to COVID-19 pneumonia who was safely and successfully treated with the compstatin-based complement C3 inhibitor AMY-101.