Emicizumab in acquired haemophilia A: about two clinical cases and literature review

Emicizumab: the hemophilia A game-changer

In hemophilia, the unmet needs regarding adherence to prophylaxis and lack of effective long-term prophylaxis regimens, especially in patients with inhibitors, led to the production of emicizumab, the first non-factor medicine for subcutaneous administration in patients with severe and moderate hemophilia A with or without factor VIII inhibitors. This review describes the research steps behind the development of this game-changing medication as well as its success in the prophylaxis of bleeding episodes, as witnessed by the results of pivotal clinical trials but also by real-life use in the frame of a still expanding global market. We also discuss potential and actual adverse events and the nuances related to clinical use, such as laboratory monitoring, development of neutralizing antidrug antibodies, risk of thrombosis/hypercoagulability and role in the management of surgical operations. The potential of emicizumab to prevent bleeding in other congenital and acquired coagulation disorders is also outlined.

Emicizumab in acquired hemophilia A: pros and cons of a new approach to the prevention and treatment of bleeding

Emicizumab, a monoclonal bispecific antibody that mimics the function of activated factor VIII (FVIII), is currently licensed for prophylactic use in patients with congenital hemophilia A with and without inhibitors. Acquired hemophilia A (AHA) is a very rare bleeding disorder caused by the development of autoantibodies that inhibit FVIII activity in plasma; males and females are equally affected. Therapeutic options for patients with AHA currently include eradication of the inhibitor with immunosuppressive treatments and management of acute bleeding with bypassing agents or recombinant porcine FVIII. More recently, several reports described the off-label use of emicizumab in patients with AHA and a phase III study is ongoing in Japan. The aims of this review are to describe the 73 reported cases, and to highlight the advantages and disadvantages of this novel approach to the prevention and treatment of bleeding in AHA.

Acquired Hemophilia A: Bleeding Pattern and Hemostatic Therapeutic Strategies

Acquired Hemophilia A (AHA) is a rare autoimmune disorder characterized by the onset of a sudden and unexpected bleeding episode in a patient with no personal or family history of bleeding diathesis, and with a typical laboratory feature, i.e., a prolonged activated partial thromboplastin time that is not otherwise explained. This bleeding disorder is caused by autoantibodies directed against the coagulation factor VIII (FVIII). AHA is idiopathic in 50% of cases and is secondary to well-defined diseases in the remaining 50%. AHA affects elderly patients although it has also been observed in the post-partum period. Bleeding manifestations are heterogeneous, ranging from mild to life-threatening bleeds involving limbs and organs. Severe bleeding with a significant decrease in hemoglobin levels must be promptly and adequately treated in order to avoid a worsening of the hemorrhages and their complications. According to international recommendations, the bypass agents (i.e., activated prothrombin complex concentrate and activated recombinant factor VII) and the replacement therapy with recombinant porcine FVIII are considered as the first-line therapy for bleeding control, due to their proven clinical efficacy. Plasma-derived or recombinant FVIII concentrates could be used as second-line treatments. Emicizumab may represent a valid and interesting therapeutic option for prophylaxis of bleeding recurrences.

Acquired Hemophilia A: An Update on the Etiopathogenesis, Diagnosis, and Treatment

Acquired haemophilia A (AHA) is a rare bleeding disorder caused by inhibitory autoantibodies against coagulation factor VIII (FVIII). AHA is a disease that most commonly affects the elderly but has also been observed in children and in the postpartum period. AHA is idiopathic in 50% of cases and is associated with autoimmune diseases, malignancies, and infections in the remaining 50%. Recently, cases of association between AHA, COVID-19 vaccination, and infection have been reported in the literature. For diagnoses, determining FVIII levels is crucial to distinguish the different causes of aPTT prolongation. Treatment of AHA is based on bypassing agents (recombinant factor VIIa, activated prothrombin complex concentrate) and porcine FVIII to control the bleeding and immunosuppressive therapy (corticosteroids, rituximab, cyclophosphamide) to suppress autoantibody production. It is important to start a prophylactic regimen to prevent further bleeding episodes until the inhibitor is negative. Recently, the series of cases reported in the literature suggest that emicizumab may provide effective and safe haemorrhage prophylaxis in the outpatient setting.

Current and future therapies for haemophilia-Beyond factor replacement therapies

Some non-factor products that work by facilitating the coagulation pathway (emicizumab) and blocking the anticoagulant pathway (fitusiran, concizumab and marstacimab) for patients with haemophilia (H) have been developed, and clinical trials using these products are currently ongoing. Prophylaxis using non-factor products by subcutaneous administration provides marked reductions of bleeding episodes in patients with HA or HB, regardless of the presence of inhibitor. Emicizumab has already been approved globally. Emicizumab alters the phenotype of patients with HA from severe to mild by maintaining trough levels of equivalent factor VIII activity (15-20 iu/dl). Phase 3 clinical trials and long-term observations assessing emicizumab revealed tolerable safety and efficacy. However, thrombotic events have occurred in patients receiving these non-factor products. Furthermore, monitoring of the haemostatic function of these products with concomitant therapy is also required in clinical practice. These products have promising haemostatic efficiency, but wider clinical experience is needed to provide optimal therapeutic strategies in the future.

Acquired Haemophilia A in four north European countries: survey of 181 patients

Acquired haemophilia A (AHA) is a rare bleeding disorder caused by acquired antibodies against coagulation factor VIII. In the Nordic countries, treatment and outcomes have not been studied in recent times. To collect retrospective data on patients diagnosed with AHA in the Nordic countries between 2006 and 2018 and compare demographic data and clinical outcomes with previously published reports, data were collected by six haemophilia centres: three Swedish, one Finnish, one Danish and one Estonian. The study included 181 patients. Median age at diagnosis was 76 (range 5-99) years, with even gender distribution. Type and severity of bleeding was comparable to that in the large European Acquired Haemophilia Registry study (EACH2). Bleedings were primarily treated with activated prothrombin complex concentrate (aPCC) with a high success rate (91%). For immunosuppressive therapy, corticosteroid monotherapy was used most frequently and this may be the cause of the overall lower clinical remission rate compared to the EACH2 study (57% vs. 72%). Survey data on 181 patients collected from four north European countries showed similar demographic and clinical features as in previous studies on AHA. aPCC was used more frequently than in the EACH2 study and the overall remission rate was lower.

Acquired hemophilia as a rare cause of excessive bleeding during dentistry: report of two cases and short review

Acquired hemophilia is a rare coagulation disorder that is not diagnosed by routine clinical laboratory tests. Thus, many perioperative or acute emergent bleeding complications remain unclear until the underlying cause is specified. We report two cases of postoperative bleeding in the context of dental surgery in which subsequent acquired hemophilia could be confirmed and present a short review from the literature.