Search Results (21)

PNH is an acquired ultrarare disease caused by a somatic mutation of PIGA gene located at band 22 of the short arm of the X chromosome, which is unable to carry out the synthesis of glycosil-phosphatidyl-inositol. The loss of complement regulators CD55 and CD59 is associated with the lack of the protective complement regulators in RBCs that become highly susceptible to complement-mediated lysis. PNH is characterized by intravascular hemolysis, high prevalence of thrombotic events, and a variable degree of bone marrow failure. It may arise from aplastic anemia, myelodysplasia and myeloproliferative neoplasms. Recently, a new clinical variant of PNH has been reported, the so-called “ahemolytic white blood cell PNH”, which may be associated with thrombotic episodes. In 2006, the introduction of eculizumab therapy has revolutionized the treatment for PNH patients. More recently, ravulizumab, crovalimab, iptacopan, danicopan, and pegcetacoplan have been introduced in the marketplace, with short/medium-term data supporting their safety and effectiveness. However, no trial has directly compared the clinical outcomes of the new drugs, and also the inclusion criteria in the various phase 3 trials were different, making a comparison between them difficult and unsatisfactory. It is conceivable that artificial intelligence and machine learning-based scoring models may be crucial for predicting the effectiveness of the anti-complement therapy. Full article

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy in which antibodies against the aquaporin-4 (AQP4) water channel produce a stereotyped group of syndromes determined by the anatomical distribution of AQP4 expression. Six core clinical presentations are recognized: optic neuritis, longitudinally extensive transverse myelitis, area postrema syndrome, acute brainstem syndrome, diencephalic syndrome, and cerebral syndrome. Because disability in NMOSD almost always accrues at discrete, treatable relapses rather than through insidious progression, early recognition, supported by prompt AQP4-IgG testing and pattern recognition on MRI, is essential to preserving vision, mobility, and independence. This review summarizes the pathophysiology, clinical and radiologic features, diagnostic evaluation, and differential diagnosis of each core syndrome and synthesizes contemporary evidence for relapse prevention. Over the past decade, the therapeutic landscape has been transformed: agents targeting complement (eculizumab, ravulizumab), the interleukin-6 receptor (satralizumab, tocilizumab), and B cells (rituximab, inebilizumab) now have randomized evidence of efficacy in seropositive disease, with complement inhibitors ranking highest across indirect treatment comparisons. Evidence in seronegative disease remains limited, no approved agents have been compared head-to-head, and the optimal role of early plasma exchange is unsettled. Emerging neuroprotective strategies and chimeric antigen receptor T-cell therapy, both of which remain experimental, may further expand options for refractory disease. Once uniformly disabling, AQP4-IgG NMOSD is now a highly treatable condition in which timely diagnosis and sustained immunotherapy can meaningfully alter long-term outcomes. Full article

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder characterized by complement-mediated hemolytic anemia and thrombosis. The first treatments approved were complement 5 inhibitors (C5is), eculizumab and ravulizumab. Recently approved treatments include pegcetacoplan, iptacopan, danicopan (as an add-on to a C5i), and crovalimab. Methods: A systematic literature review (SLR) was conducted to identify clinical evidence on all available treatments. Outcomes evaluated were hemoglobin and lactate dehydrogenase (LDH) levels, transfusion avoidance, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scores, and safety. Results: In total, 133 records met the inclusion criteria. Of these, 54 records reporting on 11 Phase 3 trials and 2 extension studies are summarized. Eight trials and one extension study evaluated complement inhibitor (CI)-naïve patients, three trials evaluated CI-experienced patients with residual anemia, and one extension study evaluated both groups. In both patient groups, all treatments led to improved outcomes. Conclusions: This SLR is the first to provide an overview of clinical trials assessing the efficacy and safety of all currently approved PNH treatments, which could help inform clinical decisions. Although some head-to-head trials are available, direct comparative evidence remains limited for several comparators, necessitating an indirect treatment comparison (ITC) to assess the efficacy and safety across the treatment landscape. Full article

Background: Acute limb ischemia (ALI) is a vascular emergency characterized by abrupt limb hypoperfusion, ischemia–reperfusion injury, and a high risk of thromboinflammatory and organ complications. Complement activation has been implicated in endothelial dysfunction, glycocalyx injury, and ischemia–reperfusion damage, but the clinical relevance of ongoing terminal complement blockade in patients presenting with ALI remains unclear, highlighting a gap between mechanistic understanding and real-world clinical outcomes. Methods: A retrospective cohort study was performed using the TriNetX federated research network. Adult patients with ALI were identified and stratified according to ongoing treatment with the C5 inhibitors eculizumab or ravulizumab. Outcomes included ischemic stroke, venous thrombosis, pulmonary embolism, arterial embolism, thrombotic disorders, acute kidney injury (AKI), and the composite outcome major adverse cardiovascular events (MACE) within 31 days. Propensity score matching was performed for demographic characteristics, cardiovascular comorbidities, complement-associated diseases and medications. Results: After propensity score matching, 112 patients remained in each cohort. Compared with matched controls, patients receiving C5 inhibition had a significantly higher risk of venous thrombosis (27.9% vs. 13.7%; p < 0.001), AKI (18.9% vs. 9.4%; p = 0.001), MACE (50.0% vs. 35.1%; p = 0.001), and thrombotic disorders (46.7% vs. 31.3%; p = 0.001). Time-to-event analyses confirmed significantly lower event-free survival for venous thrombosis (HR 2.3), AKI (HR 2.1), MACE (HR 1.6), and thrombotic disorders (HR 1.7). No significant differences were observed for ischemic stroke, pulmonary embolism, or arterial embolism. Conclusions: In patients with ALI, ongoing treatment with eculizumab or ravulizumab was not associated with an apparent reduction in short-term thromboinflammatory or cardiovascular complications. Instead, the observed outcome pattern suggests persistent vulnerability in this clinically uncommon but increasingly relevant high-risk population, although substantial residual confounding by indication and disease severity remains likely. These findings support further investigation of complement-targeted therapy, endothelial injury, and short-term vascular outcomes in ALI, and emphasize the translational relevance of linking mechanistic insights with clinical data to inform risk stratification and management strategies in this population. Full article

Background/Objectives: Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy caused by dysregulation of the alternative complement pathway, often related to genetic mutations or autoantibodies. The introduction of complement C5 inhibitors, such as eculizumab and ravulizumab, has significantly improved renal and overall outcomes. However, complement inhibition impairs host defense against encapsulated bacteria, markedly increasing the risk of invasive infections, particularly Neisseria meningitidis. Vaccination against meningococcal groups ACWY and B, along with temporary antibiotic prophylaxis, is therefore recommended before initiating anti-C5 therapy. Methods: We report the clinical course of a 13-year-old boy with aHUS secondary to anti–complement factor H (CFH) autoantibodies and CFHR3–CFHR1 homozygous deletion, treated with C5 inhibitors. Results: Despite complete meningococcal vaccination and a previous course of antibiotic prophylaxis, the patient developed meningitis during ongoing complement inhibitor therapy. Conclusions: This case highlights that breakthrough invasive infections may occur despite adherence to recommended preventive strategies. It underscores the need for sustained clinical vigilance, timely vaccine boosters, and careful reassessment of the risk–benefit balance of continued complement inhibition therapy. Full article

In this study, blood cell counts and serum C3, C4, and CH50 values at baseline and after more than 6-month drug use were measured to elucidate changes in blood cells and complements during relapse prevention therapies for aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4+ NMOSD). A total of 70 patients with AQP4+ NMOSD (87% female, median age 56 years) were enrolled. They were divided into the following treatment groups: glucocorticoids and/or immunosuppressants (GC/IS, n = 22), inebilizumab/rituximab (anti-CD19/20, n = 13), satralizumab (anti-IL-6R, n = 22), and eculizumab/ravulizumab (anti-C5, n = 13). At baseline, the blood counts and complement levels did not differ among the groups. At follow-up, the neutrophil and platelet counts in the anti-IL-6R group decreased from those at baseline (p < 0.0001 and p < 0.001, respectively). Compared with the GC/IS, anti-CD19/20, and anti-C5 groups, the anti-IL-6R group had lower levels of C3 (p < 0.0001, p < 0.01, and p < 0.05, respectively) and C4 (p < 0.0001, p < 0.01, p < 0.001, respectively). Furthermore, the anti-C5 group had significantly lower CH50 levels than the GC/IS, anti-CD19/20, and anti-IL-6R groups (p < 0.0001, p < 0.0001, p < 0.05, respectively). In addition, the anti-IL-6R group had lower CH50 levels than the GC/IS and anti-CD19/20 groups (p < 0.001 and p < 0.05, respectively). The present study demonstrated that anti-IL-6R therapy broadly and mildly suppressed the complement system and decreased the neutrophil and platelet counts. It also showed that anti-C5 therapy strongly suppressed total complement activity but did not affect the C3 and C4 levels or blood counts. These findings may have implications for the mode of action of the drugs and the risk of adverse drug reactions, including infections. Full article

Therapeutic antibodies have revolutionized hematology, offering targeted and effective treatments for both malignant and non-malignant diseases. In hematologic malignancies, anti-CD20, anti-CD19, anti-CD38, and anti–B-cell maturation antigen (BCMA) antibodies have markedly improved survival outcomes, whereas antibody–drug conjugates and bispecific antibodies continue to expand therapeutic possibilities. Besides cancer, complement inhibitors such as eculizumab, ravulizumab, and the recently approved crovalimab have redefined paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome management, and the bispecific antibody emicizumab has transformed prophylaxis in hemophilia A. Furthermore, novel antibody formats such as the trifunctional anti-CD38 × CD3 antibody (Tri-31C2) exhibit enhanced anti-myeloma activity compared to chimeric CD38 antibodies, underscoring the future potential of T-cell–redirecting designs. This review summarizes key developments in therapeutic antibodies for hematological disorders, their action mechanisms, and emerging strategies to further optimize their efficacy and safety. Full article

Background: Eculizumab, Ravulizumab, and Zilucoplan are inhibitors of terminal complement protein C5 (C5IT) approved for the treatment of generalized Myasthenia Gravis (gMG). The aim of this study is to compare the administration schedules, efficacy, and safety of these new biological therapies in a real-life setting. Methods: We enrolled 31 patients with gMG who received C5IT (Eculizumab: 7 patients; Ravulizumab: 11 patients; Zilucoplan: 13 patients). We gathered demographic, clinical data by the difference between scores at baseline (T0) and after follow-up for the MG-ADL, QMG, and MGC scales. Results: All C5IT demonstrated similar clinical efficacy, resulting in a statistically significant reduction in clinical scales scores for the MG-ADL (F = 14.7; p < 0.001), QMG (F = 14.78; p < 0.001), and MGC (F = 9.466; p < 0.001), with no significant differences among drugs (p > 0.05). No significant differences were highlighted in terms of MSE (p > 0.05). There was a decrease in the mean dose of steroid taken by patients in all three treatment groups (Eculizumab: −37%; Ravulizumab: −62%; Zilucoplan: −37%, at W34 compared to baseline). No myasthenic crises requiring hospitalization occurred during follow-up. Most of the reported adverse events were mild to moderate; the more severe events included one case of Stevens–Johnson syndrome (Ravulizumab) and episodes of pneumonia (Eculizumab, Ravulizumab). Conclusions: The comparison of C5IT did not bring out significant differences in terms of clinical efficacy and safety, representing a valid therapeutic option when traditional therapies fail to control disease symptoms. Full article

Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by fluctuating skeletal muscle weakness. Myasthenic crisis (MCr), a severe and potentially life-threatening complication, presents with respiratory failure and requires intensive care and rapid immunomodulatory intervention. Conventional MCr treatments—such as plasma exchange (PLEX), intravenous immunoglobulin (IVIG), and intravenous methylprednisolone (IVMP)—remain standard treatments; however, they present significant limitations, including delayed onset of action, adverse effects, and inconsistent efficacy. Recent therapeutic advances have led to the development of molecularly targeted therapies based on MG pathophysiology, particularly neonatal Fc receptor (FcRn) inhibitors and complement inhibitors, which have shown efficacy in refractory or maintenance settings. This review explores the potential application of these agents in MCr. We review published case reports involving FcRn inhibitors (efgartigimod, efgartigimod-SC, rozanolixizumab) and complement inhibitors (eculizumab, ravulizumab, zilucoplan), highlighting their rapid onset of action and safety profiles in MCr. While efgartigimod and eculizumab are the most commonly reported agents in MCr, data remain limited to small case series. Emerging evidence suggests these agents may offer effective alternatives to conventional therapies, with favorable safety and potential for rapid symptom resolution. We also discuss strategic considerations for therapy selection, including antibody subtype, coexisting autoimmune conditions, genetic factors, and transition to long-term maintenance. Though the current evidence is promising, large-scale randomized studies are needed to establish definitive roles for these therapies in MCr management. Full article

Myasthenia gravis is an antibody-mediated autoimmune condition characterized by defects in cholinergic transmission at the neuromuscular junction. In AchR antibody-positive patients, complement activation plays a prominent role in the disease process, which appears to be mediated by the activation of the membrane attack complex. Since IgG4 is not a good complement activator, the role of complement in MuSK antibody-positive myasthenia gravis patients is negligible. Experimental animal models of myasthenia gravis have shown promise with the antagonism of different elements of the complement cascade, with positive clinical outcomes. This has led to the development of the first C5 inhibitors approved for myasthenia gravis with AchR antibodies: eculizumab, ravulizumab, and zilucoplan. Other clinical trials are currently in progress, investigating the potential therapeutic role of other targets, including the Factor B inhibition or hepatic synthesis of the C5 protein. Other proposed potential targets that have not yet been clinically tested are also discussed in this review article. Full article

Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy (TMA) characterized by complement dysregulation, leading to microvascular thrombosis and multi-organ injury. TMAs are defined by thrombocytopenia, microangiopathic hemolytic anemia and organ dysfunction caused by small-vessel thrombosis. Unlike thrombotic thrombocytopenic purpura, which results from severe ADAMTS13 deficiency, aHUS is driven by uncontrolled activation of the alternative complement pathway. While the kidneys are most frequently affected, other vital organs can also be involved. Genetic susceptibility contributes significantly to disease risk, but a trigger such as infection, pregnancy or autoimmune disease is usually required. Diagnosis is challenging due to overlapping features with other TMAs and relies on exclusion and complement testing. C5 inhibitors, such as eculizumab and ravulizumab, have revolutionized treatment but necessitate prophylactic vaccination and ongoing clinical surveillance. While these therapies provide effective disease control, discontinuing treatment remains complex, especially in patients with complement gene mutations. New therapies targeting various points in the complement cascade are under investigation and may offer safer, more cost-effective options. Progress in genetic profiling and biomarker discovery is essential for earlier diagnosis, individualized therapy and relapse prevention. This review highlights recent advances in the understanding of aHUS pathophysiology, clinical features and evolving therapeutic strategies aimed at improving patient outcomes. Full article

Background and Objectives: Ravulizumab, a long-acting C5 complement inhibitor, was approved in the US and Europe in 2022 as an add-on therapy for the standard treatment of AChR-positive generalized MG (gMG). We share our real-world experience with adult patients receiving this therapy in Romania. Materials and Methods: Six AChR-positive gMG patients received ravulizumab through an Early Access Program (January 2023–October 2024). Patient outcomes were assessed at the therapy start and q8w using Quantitative MG (QMG), MG Activities of Daily Living (MG-ADL), and MG Quality of Life 15-item revised (MG-QoL15r) scales. Results: Age at disease onset ranged from 15 to 35 years. Four of the six patients were women. Two patients had gMG severity level of IIa, and four patients of IIb according to the Myasthenia Gravis Foundation of America (MGFA) classification. Five patients experienced rapid and sustained improvements in MG symptoms with MG-ADL score reductions ranged from −3 to −5 at 26 weeks post-ravulizumab start (except for those with a low baseline score: three and one). QMG score dropped in three patients (−2 to 12) during the treatment period, increased in two (+2 and +8), and remained stable in one (zero). Three patients showed sustained improvement in MG symptoms after ≥60 weeks. MG-QoL15r significantly dropped (−22 to −10) throughout the treatment period. One patient experienced ravulizumab-associated adverse events (vomiting, diarrhea, chills) that resolved within 24 h following symptomatic management, two to three episodes of myasthenic exacerbations during treatment, and discontinued it. Conclusions: All cases presented here had early-onset AChR antibody-positive, non-thymomatous MG. Despite differences in disease duration and underlying conditions, clinically meaningful and sustained improvements in gMG symptoms, and reduced corticosteroid doses were observed in all patients except one after adding ravulizumab to the treatment plan. Full article

Paroxysmal Nocturnal Hemoglobinuria (PNH) constitutes a rare bone marrow failure syndrome characterized by hemolytic anemia, thrombotic events (TEs), and bone marrow aplasia of variable degrees. Thrombosis is one of the major clinical manifestations of the disease, affecting up to 40% of individuals with PNH. Venous thrombosis is more prevalent, affecting mainly unusual sites, such as intrabdominal and hepatic veins. TEs might be the first clinical manifestation of PNH. Complement activation, endothelial dysfunction, hemolysis, impaired bioavailability of nitric oxide, and activation of platelets and neutrophils are implicated in the pathogenesis of TEs in PNH patients. Moreover, a vicious cycle involving the coagulation cascade, complement system, and inflammation cytokines, such as interleukin-6, is established. Complement inhibitors, such as eculizumab and ravulizumab (C5 inhibitors), have revolutionized the care of patients with PNH. C5 inhibitors should be initiated in patients with PNH and thrombosis, while they constitute a great prophylactic measure for TEs in those individuals. Anticoagulants, such as warfarin and low-molecular-weight heparin, and, in selected cases, direct oral anticoagulants (DOACs) should be used in combination with C5 inhibitors in patients who develop TEs. Novel complement inhibitors are considered an alternative treatment option, especially for those who develop extravascular or breakthrough hemolysis when terminal inhibitors are administered. Full article

The advent of recycling antibodies, leveraging pH-dependent antigen binding and optimized FcRn interaction, has advanced the field of antibody therapies, enabling extended durability and reduced dosages. Eculizumab (Soliris^®) demonstrated the efficacy of C5 inhibitors for paroxysmal nocturnal hemoglobinuria (PNH), while its derivative, ravulizumab (Ultomiris^®), recognized as a recycling antibody, extended the dosing intervals. However, limitations including intravenous administration and inefficacy in patients with the R885H single-nucleotide polymorphism (SNP) in C5 could necessitate alternative solutions. Crovalimab (PiaSky^®), a next-generation recycling antibody, overcomes these challenges with innovative charge engineering, achieving the enhanced cellular uptake of C5–crovalimab complexes and targeting a unique C5 epitope, allowing for efficacy regardless of the R885H SNP. This study highlights crovalimab’s distinctive molecular features, showing its eliminated binding to Fcγ receptors and C1q, alongside its optimized antigen binding characteristics. The impact of charge engineering was reconfirmed in mice, demonstrating faster C5 clearance than recycling antibodies. Notably, in the maintenance dosing regimen, crovalimab neutralizes approximately seven C5 molecules per antibody on average. Furthermore, its design also reduces the viscosity to facilitate high-concentration formulations suitable for subcutaneous delivery. Consequently, crovalimab offers a four-weekly subcutaneous injection regimen for PNH, marking a substantial improvement in treatment convenience and potentially transforming patients’ quality of life. Full article

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and potentially life-threatening hematologic disorder caused by a somatic mutation in a relevant portion of hematopoietic stem cells. Mutation of the phosphatidylinositol glycan biosynthesis class A (PIGA) gene prevents the expression of cell-surface proteins, including the complement regulatory proteins CD55 and CD59. With decreased or a lack of CD55 and CD59 expression on their membranes, PNH red blood cells become susceptible to complement-mediated hemolysis (symptoms of which include anemia, dysphagia, abdominal pain, and fatigue), leading to thrombosis. State-of-the-art PNH treatments act by inhibiting the dysregulated complement at distinct points in the activation pathway: late at the C5 level (C5 inhibitors, eculizumab, ravulizumab, and crovalimab), centrally at the C3 level (C3/C3b inhibitors and pegcetacoplan), and early at the initiation and amplification of the alternative pathway (factor B inhibitor, iptacopan; factor D inhibitor, danicopan). Through their differing mechanisms of action, these treatments elicit varying profiles of disease control and offer valuable insights into the molecular underpinnings of PNH. This narrative review provides an overview of the mechanisms of action of the six complement inhibitors currently approved for PNH, with a focus on the C3/C3b-targeted therapy, pegcetacoplan. Full article