Successful use of eculizumab in immediate ANCA vasculitis recurrence in a pediatric kidney transplant

BACKGROUND

Kidney transplantation is an acceptable therapy end-stage kidney disease secondary to antineutrophil cytoplasmic antibody-associated vasculitis with risk of disease recurrence ranging from 3% to 17%. Standard posttransplant immunosuppression is the mainstay of therapy after recurrence. Recently, new medications focused on complement regulation and avoidance of steroids have been shown to be effective in treating antineutrophil cytoplasmic antibody (ANCA) vasculitis with no studies in the pediatric population.

METHODS

We report a 5-year-old patient with immediate recurrence of positive myeloperoxidase (MPO)-ANCA vasculitis after deceased donor kidney transplant and the novel use of eculizumab to salvage the graft.

RESULTS

Eculizumab and transition to ravulizumab has been successful in improving graft function and maintenance of disease remission after immediate MPO-ANCA vasculitis recurrence posttransplant.

CONCLUSIONS

Complement inhibitors may be used in addition to standard immunosuppression postkidney transplant in a pediatric patient with MPO-ANCA vasculitis recurrence without higher rates of infections.

How should newer therapeutic agents be incorporated into the treatment of patients with myasthenia gravis?

Generalized myasthenia gravis (gMG) is a postsynaptic neuromuscular junction disorder that results in fatigable muscle weakness. The traditional treatment approach includes the use of acetylcholinesterase inhibitors, corticosteroids, and steroid-sparing immunosuppressant therapies (ISTs) for chronic management, whereas exacerbations and crises are managed with intravenous immunoglobulin (IVIg) and plasma exchange (PLEX). Over the past 6 years, four new therapeutic agents with novel immunological mechanisms of action-complement and neonatal Fc receptor (FcRn) inhibition-were approved as a result of clinically significant improvement in gMG symptoms of those treated with these newer agents in Phase 3 clinical trials. At present, it is unclear when and in whom to initiate these therapeutic agents and how to integrate them into the current treatment paradigm. When selecting a newer therapeutic agent, we use a simple equation: Value = Clinical Improvement/(Cost + Side Effects + Treatment Burden), which guides our decision-making. We consider using these novel therapeutic agents in two specific clinical situations. Firstly, the newer agents are fast-acting, suggesting they can be used in clinically unstable patients as "bridge therapy," and secondly, they provide additional options for those patients considered treatment-refractory. There are downsides, however, including treatment cost, unique side effect profiles, and intravenous and subcutaneous drug administration (though for some, this may be an advantage). As additional drugs enter the marketplace with unique mechanisms of action, routes of administration, and dosing schedules, the placement of the novel therapeutic agents in the gMG treatment algorithm will likely evolve.

Unexpected Relapse: Insights Into Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is a rare vasculitis that can pose a significant mortality risk given its multiorgan involvement and is the most common of the three anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides. Cardinal pathological features include necrotizing granulomas of the respiratory tract, small and medium vessel vasculitis, and glomerulonephritis. Early treatment is imperative to reduce permanent organ damage such as end-stage kidney disease. We describe the first case of GPA relapse 38 years after the initial pulmonary presentation. The patient previously had isolated lung involvement with preserved renal function, but presented with an acute kidney injury, uremia, and several constitutional symptoms. The patient was treated with corticosteroids and intermittent hemodialysis and initiated on immunosuppressants; the clinical course is highlighted by eventual renal recovery. Our purpose is to highlight the importance of treating patients to complete immunological recovery, particularly in GPA vasculitis, to prevent unnecessary relapse and further loss of renal function.

COVID-19 vaccination prevents a more severe course and treatment with complement inhibitors reduce worsening hemolysis during the Omicron pandemic in patients with PNH: a single-center study

OBJECTIVE

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disease characterized by chronic complement-mediated hemolysis. The concentrated outbreak of coronavirus disease 2019 (COVID-19) in China after 6 December 2022, provided an opportunity to observe the disease course of PNH during an active Omicron infection epidemic.

PATIENTS AND METHOD

Patients diagnosed with PNH at Peking Union Medical College Hospital (PUMCH) before 6 December 2022, were followed up until 10 April 2023. Clinical data related to coronavirus infection and hemolysis were recorded. Factors influencing the infection and severity rate of Omicron, as well as hemolysis provocation, were analyzed.

RESULTS

In total, 131 patients with PNH were included in this retrospective analysis; 87.8% were infected with Omicron. Among them, 15.7% met the criteria for severity, and 1 patient died (0.87%). No protective factors were identified against Omicron infections. However, patients with severe Omicron infection (n = 18) had a lower vaccination rate than those with non-severe infection (n = 97; p = 0.015). Among those infected (n = 115) with Omicron, there was a significant increase in lactate dehydrogenase (LDH) levels compared with those in the uninfected group (n = 16, p = 0.000). Patients with severe infections (n = 18) had even higher LDH increase rates than those without severe infections (n = 97; p = 0.002). 10 (37.0%) patients treated with complement inhibitors developed breakthrough hemolysis (BTH). Patients treated with complement inhibitors (n = 27) exhibited less severe hemolysis than treatment-naïve patients (n = 104; p = 0.003).

CONCLUSIONS

Omicron infection exacerbates hemolytic attacks in patients with PNH. Vaccination helps mitigate the severity of Omicron infection, and using complement inhibitors reduces hemolysis exacerbation.

Efficacy of innovative therapies in myasthenia gravis: A systematic review, meta-analysis and network meta-analysis

BACKGROUND AND PURPOSE

Therapy for myasthenia gravis (MG) is undergoing a profound change, with new treatments being tested. These include complement inhibitors and neonatal Fc receptor (FcRn) blockers. The aim of this study was to perform a meta-analysis and network meta-analysis of randomized and placebo-controlled trials of innovative therapies in MG with available efficacy data.

METHODS

We assessed statistical heterogeneity across trials based on the Cochrane Q test and I2 values, and mean differences were pooled using the random-effects model. Treatment efficacy was assessed after 26 weeks of eculizumab and ravulizumab, 28 days of efgartigimod, 43 days of rozanolixizumab, 12 weeks of zilucoplan, and 16, 24 or 52 weeks of rituximab treatment.

RESULTS

We observed an overall mean Myasthenia Gravis-Activities of Daily Living scale (MG-ADL) score change of -2.17 points (95% confidence interval [CI] -2.67, -1.67; p < 0.001) as compared to placebo. No significant difference emerged between complement inhibitors and anti-FcRn treatment (p = 0.16). The change in Quantitative Myasthenia Gravis scale (QMG) score was -3.46 (95% CI -4.53, -2.39; p < 0.001), with a higher reduction with FcRns (-4.78 vs. -2.60; p < 0.001). Rituximab did not significantly improve the MG-ADL (-0.92 [95% CI -2.24, 0.39]; p = 0.17) or QMG scores (-1.9 [95% CI -3.97, 0.18]; p = 0.07). In the network meta-analysis, efgartigimod had the highest probability of being the best treatment, followed by rozanolixizumab.

CONCLUSION

Anti-complement and FcRn treatments both proved to be effective in MG patients, whereas rituximab did not show a significant benefit for patients. Within the limitations of this meta-analysis, including efficacy time points, FcRn treatments showed a greater effect on QMG score in the short term. Real-life studies with long-term measurements are needed to confirm our results.

Efficacy and safety of the innovative monoclonal antibodies in adults with generalized myasthenia gravis: a Bayesian network analysis

Background

A series of clinical trials support the effectiveness of monoclonal antibodies for generalized myasthenia gravis (MG) compared to the placebo, but the priority among drugs remains unclear. Therefore, we conduct a frequentist network meta-analysis (NMA) to compare the relative effects of different drugs for generalized MG.

Methods

PubMed, Embase, Cochrane Library, and clinicaltrials.gov were systematically searched for eligible studies up to 1 June 2023. The primary outcome was efficacy (Myasthenia Gravis Activities of Daily Living [MG-ADL] score and Quantitative Myasthenia Gravis [QMG] score) and safety (adverse events [AEs]). Mean difference (MD) and risk ratio (RR) with their 95% credible intervals (95%CrIs) were used to show the effect size of continuous and categorical variables, respectively. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results

Thirteen studies involving 1167 individuals were identified for NMA. For efficacy outcomes, belimumab, efgartigimod, mezagitamab 600mg, and nipocalimab 60mg/kg were inferior to rozanolixzumab 7mg/kg (MD ranged from 2 to 3.69) and rozanolixzumab 10mg/kg (MD ranged from 2.04 to 3.72) in MG-ADL score, and rozanolixzumab had the highest rank probability (83%) according to the subjective surface under the curve ranking area (SUCRA). For QMG score, batoclimab 340mg (MD ranged from 4.32 to 8.52) and batoclimab 680mg (MD ranged from 4.11 to 9.31) were more effective than placebo and other monoclonal antibodies except for rozanolixzumab, with the highest SUCRA value (93% and 97% respectively). For safety outcomes, belimumab achieved the highest SUCRA value (89.8%) with significant statistical difference compared to rozanolixzumab 7mg/kg (RR 0.08, 95%CrI 0.01 to 0.94) and rozanolixzumab 10mg/kg (RR 0.08, 95%CrI 0.01 to 0.86).

Conclusion

While all monoclonal antibodies were superior to the placebo, rozanolixzumab and batoclimab might be the most effective for generalized MG. However, rozanolixzumab was associated with higher incidence of AEs. Given the limitations inherent in indirect comparisons, further head-to-head and extensive observational studies are necessary to confirm our findings.

Systematic review registration

https://inplasy.com/?s=202370112, identifier 202370112.

Sutimlimab: A Complement C1s Inhibitor for the Management of Cold Agglutinin Disease-Associated Hemolysis

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, safety, dosing and administration, and place in therapy of sutimlimab for the management of cold agglutinin disease (CAD)-associated hemolysis.

DATA SOURCES

A literature search of PubMed (1966-October 2022) was conducted using the keywords sutimlimab, BIVV009, and cold agglutinin. Data were also obtained from prescribing information, meeting abstracts, and clinicaltrials.gov.

STUDY SELECTION AND DATA EXTRACTION

All published prospective clinical trials, prescribing information, and meeting abstracts on sutimlimab for the treatment of CAD were reviewed.

DATA SYNTHESIS

Sutimlimab is a first-in-class complement C1s inhibitor indicated for the treatment of CAD-associated hemolysis. This approval was based on the phase III CARDINAL trial, which evaluated sutimlimab in patients with CAD-associated hemolysis. The primary endpoint of achieving a hemoglobin of ≥12 g/dL or increase of ≥2 above baseline was achieved by 54% of patients with sutimlimab in the 26-week trial. The phase III CADENZA trial was a placebo-controlled trial in which sutimlimab has demonstrated a significant improvement in the composite endpoint of hemoglobin increase of ≥1.5 g/dL, avoidance of transfusion, and avoidance of additional CAD therapies (73% sutimlimab vs 15% placebo).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS

Sutimlimab rapidly halts hemolysis, improves hemoglobin, and improves quality-of-life in patients with CAD. Safety issues with sutimlimab include infusion-related reactions and risk of serious infections with encapsulated bacteria.

CONCLUSIONS

Sutimlimab provides an additional therapeutic option in the treatment of CAD-associated hemolysis that can lead to rapid improvement in hemoglobin and anemia-related symptoms.

Crovalimab treatment in patients with paroxysmal nocturnal haemoglobinuria: Long-term results from the phase I/II COMPOSER trial

OBJECTIVES

This study reports long-term outcomes from the open-label extension (OLE) period of the Phase I/II COMPOSER trial (NCT03157635) that evaluated crovalimab in patients with paroxysmal nocturnal haemoglobinuria, who were treatment-naive or switched from eculizumab at enrolment.

METHODS

COMPOSER consists of four sequential parts followed by the OLE. The primary OLE objective was to assess long-term crovalimab safety, with a secondary objective to assess crovalimab pharmacokinetics and pharmacodynamics. Exploratory efficacy endpoints included change in lactate dehydrogenase (LDH), transfusion avoidance, haemoglobin stabilisation and breakthrough haemolysis (BTH).

RESULTS

A total 43 of 44 patients entered the OLE after completing the primary treatment period. Overall, 14 of 44 (32%) experienced treatment-related adverse events. Steady state exposure levels of crovalimab and terminal complement inhibition were maintained over the OLE. During the OLE, mean normalised LDH was generally maintained at ≤1.5× upper limit of normal, transfusion avoidance was achieved in 83%-92% of patients and haemoglobin stabilisation was reached in 79%-88% of patients across each 24-week interval. Five BTH events occurred with none leading to withdrawal.

CONCLUSIONS

Over a 3-year median treatment duration, crovalimab was well tolerated and sustained C5 inhibition was achieved. Intravascular haemolysis control, haemoglobin stabilisation and transfusion avoidance were maintained, signifying long-term crovalimab efficacy.

Complement-targeting therapeutics for ischemia-reperfusion injury in transplantation and the potential for ex vivo delivery

Organ shortages and an expanding waitlist have led to increased utilization of marginal organs. All donor organs are subject to varying degrees of IRI during the transplant process. Extended criteria organs, including those from older donors and organs donated after circulatory death are especially vulnerable to ischemia-reperfusion injury (IRI). Involvement of the complement cascade in mediating IRI has been studied extensively. Complement plays a vital role in the propagation of IRI and subsequent recruitment of the adaptive immune elements. Complement inhibition at various points of the pathway has been shown to mitigate IRI and minimize future immune-mediated injury in preclinical models. The recent introduction of ex vivo machine perfusion platforms provides an ideal window for therapeutic interventions. Here we review the role of complement in IRI by organ system and highlight potential therapeutic targets for intervention during ex vivo machine preservation of donor organs.

Evaluating ravulizumab for the treatment of children and adolescents with paroxysmal nocturnal hemoglobinuria

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal stem cell disease harvesting a somatic mutation in the phosphatidylinositol glycan class A (PIG-A) gene. This mutation results in a deficiency in cell membrane complement regulators leading to activation of the terminal complement pathway, clinically presenting as hemolytic anemia and thrombosis, and frequently associated with bone marrow failure. This condition was historically managed with supportive care and bone marrow transplant.

AREAS COVERED

This paper will review primary data on the pharmacology, efficacy, and safety of ravulizumab in the pediatric/adolescent population gathered from literature search from PubMed, abstracts from annual meetings, and medication package inserts. Eligible clinical trials identified on the clinicaltrials.gov website are also briefly discussed.

EXPERT OPINION

: The discovery of eculizumab, a monoclonal antibody against complement protein 5, has revolutionized the PNH landscape, with decreased hemolysis and risk of thrombosis, improved quality-of-life, and has become the standard of care. Ravulizumab, a longer-acting C5-inhibitor with 4 times the half-life of eculizumab, was recently approved for pediatric patients with PNH. Ravulizumab is effective, safe, and has the potential to improve quality of life further. In addition, ongoing clinical trials using second-generation complement inhibitors may provide promising new interventions in PNH.

Long-term safety and efficacy of ravulizumab in patients with paroxysmal nocturnal hemoglobinuria: 2-year results from two pivotal phase 3 studies

OBJECTIVES

The complement component 5 (C5) inhibitor ravulizumab demonstrated non-inferiority to eculizumab following 26 weeks of treatment in complement inhibitor-naïve and complement inhibitor-experienced patients with paroxysmal nocturnal hemoglobinuria (PNH; studies 301 and 302, respectively). This study aims to describe the results of both studies from 27 weeks to 2 years.

METHODS

Patients (N = 441) continued to receive ravulizumab throughout the extension period. Efficacy endpoints included lactate dehydrogenase (LDH) normalization, transfusion avoidance and fatigue score (FACIT-F). Safety analyses were also performed.

RESULTS

From 27 weeks to 2 years, improvements in LDH levels were maintained in both study populations. Transfusion avoidance was maintained in 81.9% (study 301) and 85.6% (study 302) of patients, and FACIT-F scores remained stable. Ravulizumab was well tolerated, and the incidence of adverse events (AEs) were similar between patients of both studies. Incidence of serious AEs deemed related to ravulizumab treatment was low (<3%).

CONCLUSIONS

This study reports, to date, the longest period of follow-up in over 400 patients with PNH treated with ravulizumab (662 patient-years). Long-term, ravulizumab demonstrated durable efficacy and was well tolerated, highlighting the importance of C5 inhibitors as the mainstay of PNH treatment.

A Targeted Complement Inhibitor CRIg/FH Protects Against Experimental Autoimmune Myasthenia Gravis in Rats via Immune Modulation

Antibody-induced complement activation may cause injury of the neuromuscular junction (NMJ) and is thus considered as a primary pathogenic factor in human myasthenia gravis (MG) and animal models of experimental autoimmune myasthenia gravis (EAMG). In this study, we tested whether CRIg/FH, a targeted complement inhibitor, could attenuate NMJ injury in rat MG models. We first demonstrated that CRIg/FH could inhibit complement-dependent cytotoxicity on human rhabdomyosarcoma TE671 cells induced by MG patient-derived IgG in vitro. Furthermore, we investigated the therapeutic effect of CRIg/FH in a passive and an active EAMG rodent model. In both models, administration of CRIg/FH could significantly reduce the complement-mediated end-plate damage and suppress the development of EAMG. In the active EAMG model, we also found that CRIg/FH treatment remarkably reduced the serum concentration of autoantibodies and of the cytokines including IFN-γ, IL-2, IL-6, and IL-17, and upregulated the percentage of Treg cells in the spleen, which was further verified in vitro. Therefore, our findings indicate that CRIg/FH may hold the potential for the treatment of MG via immune modulation.

Alternative Complement Pathway Inhibition Does Not Abrogate Meningococcal Killing by Serum of Vaccinated Individuals

Dysregulation of complement activation causes a number of diseases, including paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. These conditions can be treated with monoclonal antibodies (mAbs) that bind to the complement component C5 and prevent formation of the membrane attack complex (MAC). While MAC is involved in uncontrolled lysis of erythrocytes in these patients, it is also required for serum bactericidal activity (SBA), i.e. clearance of encapsulated bacteria. Therefore, terminal complement blockage in these patients increases the risk of invasive disease by Neisseria meningitidis more than 1000-fold compared to the general population, despite obligatory vaccination. It is assumed that alternative instead of terminal pathway inhibition reduces the risk of meningococcal disease in vaccinated individuals. To address this, we investigated the SBA with alternative pathway inhibitors. Serum was collected from adults before and after vaccination with a meningococcal serogroup A, C, W, Y capsule conjugate vaccine and tested for meningococcal killing in the presence of factor B and D, C3, C5 and MASP-2 inhibitors. B meningococci were not included in this study since the immune response against protein-based vaccines is more complex. Unsurprisingly, inhibition of C5 abrogated killing of meningococci by all sera. In contrast, both factor B and D inhibitors affected meningococcal killing in sera from individuals with low, but not with high bactericidal anti-capsular titers. While the anti-MASP-2 mAb did not impair SBA, inhibition of C3 impeded meningococcal killing in most, but not in all sera. These data provide evidence that vaccination can provide protection against invasive meningococcal disease in patients treated with alternative pathway inhibitors.

Targeting the Complement Cascade in the Pathophysiology of COVID-19 Disease

Severe coronavirus disease 2019 causes multi-organ dysfunction with significant morbidity and mortality. Mounting evidence implicates maladaptive over-activation of innate immune pathways such as the complement cascade as well as endothelial dysfunction as significant contributors to disease progression. We review the complement pathways, the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on these pathways, and promising therapeutic targets in clinical trials.

Cost burden of breakthrough hemolysis in patients with paroxysmal nocturnal hemoglobinuria receiving ravulizumab versus eculizumab

Objectives: Although complement inhibition is highly effective, patients with paroxysmal nocturnal hemoglobinuria (PNH) may experience intravascular breakthrough hemolysis (BTH). Underlying causes may include elevated free C5, pregnancy, or non-pregnancy complement-activating conditions (e.g. infections). This study compared BTH-related resource utilization and costs in PNH patients treated with eculizumab versus ravulizumab. Methods: A cost model was developed using data from a targeted literature review and a survey of experienced clinicians. Costs associated with BTH episodes were calculated by cause and weighted by the proportion attributed to each cause and the cost of treating each episode. The model captured direct medical costs in 2018 US dollars. Annual BTH-related healthcare resource utilization was also calculated. Results: BTH episodes in the literature were commonly associated with elevated lactate dehydrogenase and aspartate aminotransferase, hemoglobinuria, transfusion needs, and/or recurrence of PNH symptoms. The majority of BTH management costs in eculizumab-treated patients related to changing from the approved dosing regimen following an episode of BTH, rather than acute management. No ongoing dosing changes were expected for ravulizumab-treated patients following episodes of BTH, substantially reducing its ongoing management costs. Resource utilization was greater for eculizumab-treated patients than ravulizumab-treated patients due to higher incidence of BTH, and risk of elevated free C5-related BTH. Total incremental cost was substantially lower for ravulizumab- vs eculizumab-treated patients ($407 vs $9379); results were consistent when pregnant women were not included ($386 vs $3472). Conclusion: Overall resource use and costs for BTH are estimated to be lower for PNH patients receiving ravulizumab compared with eculizumab.

Emerging recognition of the complement system in hepatic ischemia/reperfusion injury, liver regeneration and recovery (Review)

Hepatic ischemia/reperfusion injury (IRI) is a result of the ischemic cascade and may occur in the settings of liver trauma, resection and transplantation. Components of the complement system have been indicated to be mediators of hepatic IRI and regulators of liver regeneration. As such, their potential to mediate both beneficial and harmful effects render them key targets for therapy. In the present study, the mechanisms of complement mediating hepatic IRI were discussed with a focus on the different functions of complement in hepatic injury and liver recovery, and an explanation for this apparent paradox is provided, i.e. that the complement products C3a and C5a have an important role in liver damage; however, C3a and C5a are also necessary for liver regeneration. Furthermore, situated at the end of the complement activation cascade, the membrane attack complex is crucial in hepatic IRI and inhibiting the complex with a site-targeted murine complement inhibitor, complement receptor 2-CD59, may improve liver regeneration after partial hepatectomy, even when hepatectomy is combined with ischemia and reperfusion.

One-year outcomes from a phase 3 randomized trial of ravulizumab in adults with paroxysmal nocturnal hemoglobinuria who received prior eculizumab

Ravulizumab every 8 weeks showed non‐inferiority to eculizumab every 2 weeks in a 26‐week, phase 3, randomized controlled trial in adults with paroxysmal nocturnal hemoglobinuria (PNH) who were clinically stable on eculizumab (NCT03056040). We report results from the first 26 weeks of the extension period in which patients continued ravulizumab (n = 96) or switched from eculizumab to ravulizumab (n = 95). At week 52, mean (SD) lactate dehydrogenase levels increased 8.8% (29%) with ravulizumab‐ravulizumab and 5.8% (27%) with eculizumab‐ravulizumab from primary evaluation period baseline. During the extension period, four patients (ravulizumab‐ravulizumab, n = 3; eculizumab‐ravulizumab, n = 1) experienced breakthrough hemolysis, but none associated with serum free C5 ≥ 0.5 μg/mL. Mean Functional Assessment of Chronic Illness Therapy (FACIT)‐Fatigue scores remained stable through week 52. During the extension period, proportions of patients avoiding transfusion remained stable (ravulizumab‐ravulizumab, 86.5%; eculizumab‐ravulizumab, 83.2%); 81.2% and 81.1%, respectively, had stabilized hemoglobin. All patients maintained serum free C5 levels < 0.5 μg/mL. Adverse events were generally similar between groups, and rates were lower in the extension period. Adults with PNH on stable eculizumab therapy who received ravulizumab over 52 weeks experienced durable efficacy, with consistent efficacy in patients who received eculizumab during the primary evaluation period and then switched to ravulizumab. Ravulizumab was well tolerated.

Use of Eculizumab in Pediatric Patients With Transplant Associated Thrombotic Microangiopathy

Background: Transplant-associated thrombotic microangiopathy (TA-TMA) is a serious complication of hematopoietic stem cell transplantation (HSCT) associated with high morbidity and mortality. High-risk TA-TMA (hrTA-TMA) is characterized by multifactorial endothelial damage caused by environmental stressors, dysregulation of the complement system, and genetic predisposition. Complement inhibitors have significantly decreased mortality and are the current treatment of choice. In this article, we describe our experience with the use of eculizumab in pediatric patients diagnosed with hrT-TMA after HSCT. Method: Retrospective study of pediatric patients with hrTA-TMA treated with eculizumab between January 2016 and December 2020. Results: Four pediatric patients aged 1, 12, 14, and 17 years at the time of HSCT were diagnosed with hrTA-TMA and treated with eculizumab during the study. At diagnosis, they all had renal impairment with proteinuria, and hypertension under treatment with at least two antihypertensive drugs. The patient who presented multisystemic involvement died instead of treatment. The three patients with exclusive renal involvement achieved TA-TMA resolution after treatment with eculizumab for 65, 52, and 40.6 weeks and were able to stop treatment. The two patients with follow-up data one year after eculizumab withdrawal sustained a favorable response. Eculizumab was well tolerated, and with adequate vaccination and antibiotic prophylaxis, did not increase the risk of infection. Conclusions: Eculizumab appears to be both safe and effective for the treatment of hrTA-TMA in patients with renal impairment. Early diagnosis and initiation of treatment may improve response. Eculizumab withdrawal can be contemplated in patients who achieve laboratory and clinical resolution of TA-TMA.

One-year efficacy and safety of ravulizumab in adults with paroxysmal nocturnal hemoglobinuria naïve to complement inhibitor therapy: open-label extension of a randomized study

Background:

Ravulizumab, the only long-acting complement C5 inhibitor for adults with paroxysmal nocturnal hemoglobinuria (PNH), demonstrated non-inferiority to eculizumab after 26 weeks of treatment in complement inhibitor-naïve patients during a phase III randomized controlled trial. We present open-label extension results with up to 52 weeks of treatment.

Methods:

Patients assigned to ravulizumab every 8 weeks (q8w) or eculizumab every 2 weeks during the randomized primary evaluation period received ravulizumab q8w during the 26-week extension. Efficacy endpoints were lactate dehydrogenase (LDH) normalization, transfusion avoidance, breakthrough hemolysis (BTH), LDH levels, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scale, and stabilized hemoglobin. Serum free C5 levels and safety were assessed. Outcomes as of the data cut-off (4 September 2018) were summarized using descriptive statistics.

Results:

Overall, 124 patients continued ravulizumab, and 119 switched from eculizumab to ravulizumab. During the extension, 43.5% and 40.3% of patients in the ravulizumab–ravulizumab and eculizumab–ravulizumab arms, respectively, achieved LDH normalization; 76.6% and 67.2% avoided transfusion. BTH decreased in the eculizumab–ravulizumab arm; no events were associated with free C5 ⩾0.5 μg/mL while receiving ravulizumab. Overall, 73.4% and 65.5% of patients in the ravulizumab–ravulizumab and eculizumab–ravulizumab arms, respectively, achieved stabilized hemoglobin. Similar proportions of patients achieved ⩾3-point improvement in FACIT-Fatigue at week 52 (ravulizumab–ravulizumab, 64.5%; eculizumab–ravulizumab, 57.1%). All patients maintained free C5 <0.5 μg/mL during the ravulizumab extension, including those who experienced C5 excursions ⩾0.5 μg/mL while receiving eculizumab during the primary evaluation period. Adverse events were comparable between groups and decreased over time.

Conclusion:

In adult, complement inhibitor–naïve patients with PNH, ravulizumab q8w for up to 52 weeks demonstrated durable efficacy and was well tolerated, with complete and sustained free C5 inhibition and a decreased incidence of BTH with no events associated with loss of free C5 control.

Trial registration:

ClinicalTrials.gov identifier, NCT02946463

C2 IgM Natural Antibody Enhances Inflammation and Its Use in the Recombinant Single Chain Antibody-Fused Complement Inhibitor C2-Crry to Target Therapeutics to Joints Attenuates Arthritis in Mice

Natural IgM antibodies (NAbs) have been shown to recognize injury-associated neoepitopes and to initiate pathogenic complement activation. The NAb termed C2 binds to a subset of phospholipids displayed on injured cells, and its role(s) in arthritis, as well as the potential therapeutic benefit of a C2 NAb-derived ScFv-containing protein fused to a complement inhibitor, complement receptor-related y (Crry), on joint inflammation are unknown. Our first objective was to functionally test mAb C2 binding to apoptotic cells from the joint and also evaluate its inflammation enhancing capacity in collagen antibody-induced arthritis (CAIA). The second objective was to generate and test the complement inhibitory capacity of C2-Crry fusion protein in the collagen-induced arthritis (CIA) model. The third objective was to demonstrate in vivo targeting of C2-Crry to damaged joints in mice with arthritis. The effect of C2-NAb on CAIA in C57BL/6 mice was examined by inducing a suboptimal disease. The inhibitory effect of C2-Crry in DBA/1J mice with CIA was determined by injecting 2x per week with a single dose of 0.250 mg/mouse. Clinical disease activity (CDA) was examined, and knee joints were fixed for analysis of histopathology, C3 deposition, and macrophage infiltration. In mice with suboptimal CAIA, at day 10 there was a significant (p < 0.017) 74% increase in the CDA in mice treated with C2 NAb, compared to mice treated with F632 control NAb. In mice with CIA, at day 35 there was a significant 39% (p < 0.042) decrease in the CDA in mice treated with C2-Crry. Total scores for histopathology were also 50% decreased (p < 0.0005) in CIA mice treated with C2-Crry. C3 deposition was significantly decreased in the synovium (44%; p < 0.026) and on the surface of cartilage (42%; p < 0.008) in mice treated with C2-Crry compared with PBS treated CIA mice. Furthermore, C2-Crry specifically bound to apoptotic fibroblast-like synoviocytes in vitro, and also localized in the knee joints of arthritic mice as analyzed by in vivo imaging. In summary, NAb C2 enhanced arthritis-related injury, and targeted delivery of C2-Crry to inflamed joints demonstrated disease modifying activity in a mouse model of human inflammatory arthritis.

ARGX-117, a therapeutic complement inhibiting antibody targeting C2

Background

Activation of the classical and lectin pathway of complement may contribute to tissue damage and organ dysfunction of antibody-mediated diseases and ischemia-reperfusion conditions. Complement factors are being considered as targets for therapeutic intervention.

Objective

We sought to characterize ARGX-117, a humanized inhibitory monoclonal antibody against complement C2.

Methods

The mode-of-action and binding characteristics of ARGX-117 were investigated in detail. Furthermore, its efficacy was analyzed in in vitro complement cytotoxicity assays. Finally, a pharmacokinetic/pharmacodynamic study was conducted in cynomolgus monkeys.

Results

Through binding to the Sushi-2 domain of C2, ARGX-117 prevents the formation of the C3 proconvertase and inhibits classical and lectin pathway activation upstream of C3 activation. As ARGX-117 does not inhibit the alternative pathway, it is expected not to affect the antimicrobial activity of this complement pathway. ARGX-117 prevents complement-mediated cytotoxicity in in vitro models for autoimmune hemolytic anemia and antibody-mediated rejection of organ transplants. ARGX-117 exhibits pH- and calcium-dependent target binding and is Fc-engineered to increase affinity at acidic pH to the neonatal Fc receptor, and to reduce effector functions. In cynomolgus monkeys, ARGX-117 dose-dependently reduces free C2 levels and classical pathway activity. A 2-dose regimen of 80 and 20 mg/kg separated by a week, resulted in profound reduction of classical pathway activity lasting for at least 7 weeks.

Conclusions

ARGX-117 is a promising new complement inhibitor that is uniquely positioned to target both the classical and lectin pathways while leaving the alternative pathway intact.

A Phase 3 Open-label, Randomized, Controlled Study to Evaluate the Efficacy and Safety of Intravenously Administered Ravulizumab Compared with Best Supportive Care in Patients with COVID-19 Severe Pneumonia, Acute Lung Injury, or Acute Respiratory Distress Syndrome: A structured summary of a study protocol for a randomised controlled trial

Objectives

Primary Objective

• To evaluate the effect of ravulizumab, a long-acting complement (C5) inhibitor plus best supportive care (BSC) compared with BSC alone on the survival of patients with COVID-19.

Secondary Objectives

• Number of days free of mechanical ventilation at Day 29

• Duration of intensive care unit stay at Day 29

• Change from baseline in Sequential Organ Failure Assessment (SOFA) score at Day 29

• Change from baseline in peripheral capillary oxygen saturation/ fraction of inspired oxygen (SpO2 /FiO2) at Day 29

• Duration of hospitalization at Day 29

• Survival (based on all-cause mortality) at Day 60 and Day 90

Safety

• Incidence of treatment-emergent adverse events and treatment-emergent serious adverse events.

PK/PD/Immunogenicity

• Change in serum ravulizumab concentrations over time

• Change in serum free and total C5 concentrations over time

• Incidence and titer of anti-ALXN1210 antibodies

Biomarkers

• Change in absolute level of soluble biomarkers in blood associated with complement activation, inflammatory processes, and hypercoagulable states over time

Exploratory

• Incidence of progression to renal failure requiring dialysis at Day 29

• Time to clinical improvement (based on a modified 6-point ordinal scale) over 29 days

• SF-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores at Day 29 (or discharge), Day 60, and Day 90

• EuroQol 5-dimension 5-level (EQ-5D-5L) scores at Day 29 (or discharge), Day 60, and Day 90

Trial design

This is a multicenter Phase 3, open-label, randomized, controlled, study.

The study is being conducted in acute care hospital settings in the United States, United Kingdom, Spain, France, Germany, and Japan.

Participants

Male or female patients at least 18 years of age, weighing ≥ 40 kg, admitted to a designated hospital facility for treatment will be screened for eligibility in this study.

Key Inclusion criteria

• Confirmed diagnosis of SARS-CoV-2 infection (eg, via polymerase chain reaction [PCR] and/or antibody test) presenting as severe COVID-19 requiring hospitalization

• Severe pneumonia, acute lung injury, or ARDS confirmed by computed tomography (CT) or X-ray at Screening or within the 3 days prior to Screening, as part of the patient’s routine clinical care

• Respiratory distress requiring mechanical ventilation, which can be either invasive (requiring endotracheal intubation) or non-invasive (with continuous positive airway pressure [CPAP] or bilevel positive airway pressure [BiPAP])

Key Exclusion criteria

• Patient is not expected to survive for more than 24 hours

• Patient is on invasive mechanical ventilation with intubation for more than 48 hours prior to Screening

• Severe pre-existing cardiac disease (ie, NYHA Class 3 or Class 4, acute coronary syndrome, or persistent ventricular tachyarrhythmias)

• Patient has an unresolved Neisseria meningitidis infection

Excluded medications and therapies

• Current treatment with a complement inhibitor

• Intravenous immunoglobulin (IVIg) within 4 weeks prior to randomization on Day 1

Excluded prior/concurrent clinical study experience

• Treatment with investigational therapy in a clinical study within 30 days before randomization, or within 5 half-lives of that investigational therapy, whichever is greater

• Exceptions

a. Investigational therapies will be allowed if received as part of best supportive care through an expanded access protocol or emergency approval for the treatment of COVID-19.

b. Investigational antiviral therapies (such as remdesivir) will be allowed even if received as part of a clinical study.

Intervention and comparator

The study consists of a Screening Period of up to 3 days, a Primary Evaluation Period of 4 weeks, a final assessment at Day 29, and a Follow-up Period of 8 weeks. For patients randomized to ravulizumab plus BSC, a weight-based dose of ravulizumab (≥40 to < 60 kg/2400 mg, 60 to < 100 kg/2700 mg, ≥ 100 kg/3000 mg) will be administered on Day 1. On Day 5 and Day 10, additional doses of 600 mg (≥40 to <60 kg) or 900 mg (>60 kg) ravulizumab will be administered and on Day 15 patients will receive 900 mg ravulizumab. There is no active or placebo comparator in this open-label clinical trial. The total duration of each patient’s participation is anticipated to be approximately 3 months.

Main outcomes

The primary efficacy outcome of this study is survival (based on all-cause mortality) at Day 29.

Randomisation

Patients will be randomized in a 2:1 ratio (ravulizumab plus BSC:BSC alone). Randomization will be stratified by intubated or not intubated on Day 1. Computer-generated randomization lists will be prepared by a third party under the direction of the sponsor. Investigators, or designees, will enrol patients and then obtain randomization codes using an interactive voice/web response system. The block size will be kept concealed so that investigators cannot select patients for a particular treatment assignment.

Blinding (masking): This is an open-label study.

Numbers to be randomised (sample size): Approximately 270 patients will be randomly assigned in a 2:1 ratio to ravulizumab plus BSC (n=180) or BSC alone (n=90).

Trial status

Protocol Number: ALXN1210-COV-305

Original Protocol: 09 Apr 2020

Protocol Amendment 1 (Global): 13 Apr 2020

Protocol Amendment 2 (Global): 17 Apr 2020

Protocol Amendment 3 (Global): 09 Jun 2020

Recruitment is currently ongoing.

Recruitment was initiated on 11 May 2020.

We expect recruitment to be completed by 30 Nov 2020.

Trial registration

Clinicaltrials.gov: Protocol Registry Number: NCT04369469; First posted; 30 Apr 2020

EU Clinical Trials Register: EudraCT Number: https://www.clinicaltrialsregister.eu/ctr-search/search?query=ALXN1210-COV-305, Start date: 07 May 2020

Full protocol

The full redacted protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Eculizumab as a promising treatment in thymoma-associated myasthenia gravis

Myasthenia gravis is a chronic autoimmune disorder caused by antibodies directed against the neuromuscular junction. Some patients may have an associated thymoma, which confers a worse prognosis. Eculizumab, a monoclonal antibody that inhibits the activation of terminal complement, has recently been approved for the treatment of refractory generalized myasthenia gravis. This is an early case report of thymoma-associated refractory myasthenia gravis successfully treated with eculizumab in a real-world setting.

Ravulizumab: a novel C5 inhibitor for the treatment of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare stem cell disorder characterized by hemolytic anemia, bone marrow failure, and thrombosis. Until recently, the complement inhibitor, eculizumab, was the only United States Food and Drug Administration (US FDA)-approved therapy for the treatment of PNH. Although effective, eculizumab requires a frequent dosing schedule that can be burdensome for some patients and increases the risk of breakthrough intravascular hemolysis. Ravulizumab, an eculizumab-like monoclonal antibody engineered to have a longer half-life, is intended to provide the same benefits as eculizumab but with a more convenient and effective dosing schedule. In two recently published phase III non-inferiority trials, ravulizumab was found to be non-inferior to eculizumab both in efficacy and safety for the treatment of patients with PNH. Based on these results, ravulizumab was approved by the US FDA on 21 December 2018 and is currently under regulatory review in both the European Union and Japan.

Identification of complement inhibitory activities of two chemotherapeutic agents using a high-throughput cell imaging-based screening assay

Excessive complement activation contributes significantly to the pathogeneses of various diseases. Currently, significant developmental research efforts aim to identify complement inhibitors with therapeutic uses have led to the approval of one inhibitor for clinical use. However, most existing complement inhibitors are based on monoclonal antibodies, which have many drawbacks such as high costs and limited administration options. With this report, we establish an inexpensive, cell imaging-based high-throughput assay for the large-scale screening of potential small molecule complement inhibitors. Using this assay, we screened a library containing 3115 bioactive chemical compounds and identified cisplatin and pyridostatin as two new complement inhibitors in addition to nafamostat mesylate, a compound with known complement inhibitory activity. We further demonstrated that cisplatin and pyridostatin inhibit C5 convertases in the classical pathway of complement activation but have no effects on the alternative pathway of complement activation. In summary, this work has established a simple, large-scale, high-throughput assay for screening novel complement inhibitors and discovered previously unknown complement activation inhibitory activities for cisplatin and pyridostatin.

Viral-derived complement inhibitors: current status and potential role in immunomodulation

The complement system is one of the body's major innate immune defense mechanisms in vertebrates. Its function is to detect foreign bodies and promote their elimination through opsonisation or lysis. Complement proteins play an important role in the immunopathogenesis of several disorders. However, excessive complement activation does not confer more protection but instead leads to several autoimmune and inflammatory diseases. With inappropriate activation of the complement system, activated complement proteins and glycoproteins may damage both healthy and diseased tissues. Development of complement inhibitors represents an effective approach in controlling dysregulated complement activity and reducing disease severity, yet few studies have investigated the nature and role of novel complement inhibitory proteins of viral origin. Viral complement inhibitors have important implications in understanding the importance of complement inhibition and their role as a promising novel therapeutic approach in diseases caused by dysregulated complement function. In this review, we discuss the role and importance of complement inhibitors derived from several viruses in the scope of human inflammatory and autoimmune diseases.

Excessive activation of the alternative complement pathway in autosomal dominant polycystic kidney disease

OBJECTIVES

The complement system is involved in many immune complex-mediated kidney diseases, yet its role in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD) has not been examined in detail.

METHODS AND RESULTS

Screening of the glycoproteome of urine samples from ADPKD patients revealed that levels of complement factor B (CFB), serpin peptidase inhibitor, complement component 1 inhibitor (SERPING1) and complement component 9 (C9) increased, whereas complement component 1, r subcomponent-like (C1RL), CD55 and CD59 levels decreased with disease progression. Immunostaining and Western blot analysis confirmed the enhanced expression of CFB and C9 in cystic kidneys from ADPKD patients. Immunostaining also showed that the expressions of CFB and C9 in renal biopsy tissues from patients with other types of chronic kidney disease were lower than in tissues from ADPKD patients. The effect of the complement inhibitor rosmarinic acid (RMA) was evaluated in Pkd1(-/-) mice and Han:SPRD Cy/+ rats. Compared with vehicle-treated Pkd1(-/-) animals, RMA-treated mice had significantly lower serum creatinine (-50%) and blood urea nitrogen (-78%) levels, two kidneys/body weight ratio (-60%) and renal cystic index (-60%). Similar results were found in Cy/+ rats. Lower numbers of Ki67-positive nuclei and inflammatory cells and reduced fibrosis were observed in both animal models upon treatment with RMA.

CONCLUSIONS

These results suggest that excessive activation of the alternative complement pathway is associated with ADPKD progression, probably mediated by cyst-lining epithelial cell proliferation, tubulointerstitial inflammatory cell infiltration and fibrosis. Targeting the complement system might represent a new therapeutic strategy for ADPKD.

Conjugation to albumin-binding molecule tags as a strategy to improve both efficacy and pharmacokinetic properties of the complement inhibitor compstatin

The compstatin family of complement inhibitors has shown promise in various immuno-inflammatory disorders. Although recent analogues show beneficial pharmacokinetics, further extension of the plasma half-life is expected to benefit systemic application of these peptidic inhibitors. We therefore synthesized conjugates of compstatin analogues and albumin-binding molecules (ABM) to increase circulatory residence. Equilibrium dialysis in complement-depleted serum showed a marked increase in plasma protein binding from <8 % to >99 % for a resulting chimera (ABM2-Cp20). Further analysis confirmed interaction with albumin from different species, primarily via site II. Importantly, ABM2-Cp20 bound 20-fold stronger to its target protein C3b (KD =150 pM) than the parent peptide. Kinetic and in silico analysis suggested that ABM2 occupies a secondary site on C3b and improves the dissociation rate via additional contacts. Addition of an ABM modifier thereby not only improved plasma protein binding but also produced the most potent compstatin analogue to date with potential implications for the treatment of systemic complement-related diseases.

Molecular basis for complement recognition and inhibition determined by crystallographic studies of the staphylococcal complement inhibitor (SCIN) bound to C3c and C3b

The human complement system plays an essential role in innate and adaptive immunity by marking and eliminating microbial intruders. Activation of complement on foreign surfaces results in proteolytic cleavage of complement component 3 (C3) into the potent opsonin C3b, which triggers a variety of immune responses and participates in a self-amplification loop mediated by a multi-protein assembly known as the C3 convertase. The human pathogen Staphylococcus aureus has evolved a sophisticated and potent complement evasion strategy, which is predicated upon an arsenal of potent inhibitory proteins. One of these, the staphylococcal complement inhibitor (SCIN), acts at the level of the C3 convertase (C3bBb) and impairs downstream complement function by trapping the convertase in a stable but inactive state. Previously, we have shown that SCIN binds C3b directly and competitively inhibits binding of human factor H and, to a lesser degree, that of factor B to C3b. Here, we report the co-crystal structures of SCIN bound to C3b and C3c at 7.5 and 3.5 A limiting resolution, respectively, and show that SCIN binds a critical functional area on C3b. Most significantly, the SCIN binding site sterically occludes the binding sites of both factor H and factor B. Our results give insight into SCIN binding to activated derivatives of C3, explain how SCIN can recognize C3b in the absence of other complement components, and provide a structural basis for the competitive C3b-binding properties of SCIN. In the future, this may suggest templates for the design of novel complement inhibitors based upon the SCIN structure.

The structure of OMCI, a novel lipocalin inhibitor of the complement system

The complement (C) system is a potent innate immune defence system against parasites. We have recently characterised and expressed OmCI, a 16 kDa protein derived from the soft tick Ornithodoros moubata that specifically binds C5, thereby preventing C activation. The structure of recombinant OmCI determined at 1.9 A resolution confirms a lipocalin fold and reveals that the protein binds a fatty acid derivative that we have identified by mass spectrometry as ricinoleic acid. We propose that OmCI could sequester one of the fatty acid-derived inflammatory modulators from the host plasma, thereby interfering with the host inflammatory response to the tick bite. Mapping of sequence differences between OmCI and other tick lipocalins with different functions, combined with biochemical investigations of OmCI activity, supports the hypothesis that OmCI acts by preventing interaction with the C5 convertase, rather than by blocking the C5a cleavage site.