How the Availability of Anti-C5a Agents Could Change the Management of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

BACKGROUND: Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a cluster of potentially life-threatening disorders, often involving the kidney with a necrotizing crescentic glomerulonephritis with scanty deposition of immunoglobulins and complement. Historically the role of complement has been considered ancillary. Recently, an anti-myeloperoxidase (MPO) AAV model in complement-deficient mice has shown an involvement for the complement cascade in the development of the renal injuries. Further animal studies showing that in contrast to mice deficient for factor B and C5 animals deficient for C4 were susceptible to AAV development by injection of anti-MPO antibodies emphasized the specific involvement of the alternative pathway. Consonantly, the C5a receptor (Cd88) blockade was found to protect mice from MPO-AAV. CCX168, i.e., avacopan, a powerful inhibitor of C5a receptor that can be administered orally, was shown to reduce the proinflammatory effects of C5a and abolish the activation of neutrophils, their migration and adherence to endothelium, and the vascular endothelial cell retraction that increases permeability. SUMMARY: Avacopan was found to be safe in healthy volunteers given a wide range of doses in a phase 1 clinical trial. The phase 2 trial CLEAR assessed the possibility to decrease dose or entirely replace glucocorticosteroids in the standard-of-care therapy of AAV. Avacopan, added to CYC or RTX either in combination with GCs or not, shortened the time to remission in patients with either newly diagnosed or relapsing AAV. The phase 3 ADVOCATE study compared the ability of an avacopan-associated regimen to induce and sustain remission in AAV patients versus a conventional GC-associated scheme. Remission at week 26 was observed in 72.3% of patients given avacopan and in 70.1% of those given prednisone. Sustained remission at week 52 (second primary endpoint) was obtained in 65.7% of patients given avacopan and in 54.9% receiving prednisone. The avacopan-associated regimen was noninferior at week 26 and superior at week 52 in sustaining remission as compared to the GC-based scheme. KEY MESSAGES: The results of the ADVOCATE trial opened new prospects for the treatment of AAV and also other immune-mediated diseases with renal involvement. The possible position of avacopan in a routine clinical setting and its possible indications in specific subsets of patients with AAV are extensively discussed.

Successful outcome with eculizumab treatment in a patient with antiphospholipid syndrome presenting with an unusual thrombotic storm.

Catastrophic Antiphospholipid Syndrome (CAPS) is a life-threatening complication of APS requiring complex management to optimize patient outcome. We describe a 54-year-old man with APS with history of splanchnic vein thrombosis, a Factor II G20210A heterozygote, autoimmune hemolytic anemia and thrombocytopenia. He developed sudden onset of severe flank pain due to spontaneous bilateral adrenal hemorrhage while on warfarin with a therapeutic INR. Despite unfractionated heparin and initial clinical improvement, severe thrombocytopenia developed requiring dexamethasone, rituximab, and romiplostim. Hospitalization was complicated further by thrombosis of the inferior vena cava, pulmonary embolism, and painful violaceous patches on his neck and ear cartilages. Punch biopsy of lesions revealed C5b-C9 deposition of small vessel thromboses. Although the inciting event for his thrombotic storm remains uncertain, anti-complement therapy with eculizumab provided rapid and durable lesion resolution. Eculizumab was discontinued after 6 months and patient remains in remission without recurrent thrombosis. This case provides insight on the management of CAPS, including the use of eculizumab.

Safety and Efficacy of Eculizumab Therapy in Multiple Sclerosis: A Case Series.

(1) Background: Complement system activation has been proposed as one of the different factors that contribute to Multiple Sclerosis (MS) pathogenesis. In this study, we aimed to describe the potential effects of eculizumab, an anticomplement therapy, on MS disease activity in a cohort of relapsing-remitting (RR) MS patients who discontinued IFN-ß therapy due to IFN-ß-related thrombotic microangiopathy (TMA) onset. (2) Methods: In this retrospective observational multicentric study, we searched for all patients with MS treated by eculizumab with a survey of several nephrological and neurological centers (over 45 centers). (3) Results: Nine patients were included. The mean follow-up time under eculizumab was 3.72 ± 2.58 years. There were no significant differences in disease activity (EDSS, relapses, new T2, and/or Gd-enhancing lesions at MRI) considering the two years before and after eculizumab therapy. No adverse events potentially related to eculizumab therapy were reported during follow-up. (4) Conclusions: In this preliminary study, we described a good safety profile for eculizumab therapy in MS. However, the available data are not sufficient to make firm conclusions about the possible efficacy of eculizumab as a disease-modifying therapy for MS patients.

Complement in Kidney Transplantation.

The complement system is considered to be an important part of innate immune system with a significant role in inflammation processes. The activation can occur through classical, alternative, or lectin pathway, resulting in the creation of anaphylatoxins C3a and C5a, possessing a vast spectrum of immune functions, and the assembly of terminal complement cascade, capable of direct cell lysis. The activation processes are tightly regulated; inappropriate activation of the complement cascade plays a significant role in many renal diseases including organ transplantation. Moreover, complement cascade is activated during ischemia/reperfusion injury processes and influences delayed graft function of kidney allografts. Interestingly, complement system has been found to play a role in both acute cellular and antibody-mediated rejections and thrombotic microangiopathy. Therefore, complement system may represent an interesting therapeutical target in kidney transplant pathologies.