Treatment for patients with type 3 von Willebrand disease and alloantibodies: a case report

Emicizumab in Type 3 von Willebrand Disease: Report of a Case with an Alloantibody and Literature Review

Type 3 von Willebrand disease (VWD), the most severe form of VWD, is an inherited recessive bleeding disorder caused by the complete deficiency of von Willebrand factor (VWF). The reported prevalence is 1 per million but varies worldwide according to the frequency of consanguineous marriages. The clinical phenotype is characterized not only by mucocutaneous bleedings, but also by hemarthroses and muscle hematoma, as in patients with moderate hemophilia. Long-term prophylaxis with factor (F)VIII/VWF concentrates is recommended in patients with a history of severe and frequent bleeds. A rare complication of replacement therapy is the development of alloantibodies against VWF, with the consequences of an ineffective therapy and risk of anaphylactic reactions upon treatment. Emicizumab is the first bispecific monoclonal antibody that mimics FVIII coagulant activity and is approved for prophylaxis of bleeding in patients with inherited hemophilia A with or without inhibitors and recently also for acquired hemophilia. In this manuscript we report and discuss available data in the literature on the use of emicizumab in type 3 VWD and describe the case of a female patient with type 3 VWD with a history of alloantibodies against VWF and posttransfusion anaphylaxis, recently and successfully put on off-label prophylaxis with emicizumab.

Targeting von Willebrand disease: the current status and future directions of management therapies

INTRODUCTION

von Willebrand disease (VWD) is the commonest inherited bleeding disorder, and is typically caused by deficits in the quantity or quality of von Willebrand factor (VWF).

AREAS COVERED

This review describes the main clinical, diagnostic, and therapeutic aspects of VWD, with particular attention to its management. In addition, standard and avant-garde replacement therapies based on the use of VWF are discussed.

EXPERT OPINION

The goal of treatment for VWD is to reverse the double hemostatic defect resulting from the abnormal or reduced expression of VWF and the concomitant factor VIII (FVIII) deficiency. Treatment consists of managing any bleeds and both short-term prophylaxis (i.e. for surgery or invasive procedures) and long-term prophylaxis. While desmopressin is suitable for most patients with type 1 VWD, VWF/FVIII concentrates are the treatment of choice for the other types of VWD. Beside plasma-derived VWF/FVIII concentrates, whose safety and efficacy have been demonstrated by several clinical trials, products containing only VWF, obtained by plasma fractionation and recombinant DNA technology, have become available and marketed more recently. The clinical use of these VWF-only products is particularly attractive in the setting of surgery and long-term prophylaxis, such as the prevention of recurrent gastrointestinal bleeding in cases of angiodysplasia.

Rare Occurrence of Inhibitors in Von Willebrand Disease: A Case Report

Introduction: Type 3 Von Willebrand Disease (VWD) is the least common but the most severe form of a disease, with a prevalence of about 0. 5 to 1 per million in Western countries. The prevalence of type 3 VWD in the developing countries, with a high degree of consanguinity, is about 6 per million. Moreover, due to underdiagnosis of the milder cases, the prevalence of type 3 VWD is about 50% of the cases. Rarely, some patients develop the Von Willebrand Factor (VWF) inhibitors, which may subsequently develop severe anaphylactic reactions on further exposure to the VWF containing factor replacement therapy. The prevalence of inhibitor development in patients with type 3 VWD has been shown to be in the range of 5.8 to 9.5%. In the absence of a gold standard assay for the quantitation of VWF inhibitors, a correct diagnosis and management of these patients are often challenging.

Objectives: The objective of this study is to standardize the Bethesda assay for the VWF inhibitors and to estimate the VWD inhibitor titer in two cases of congenital type 3 VWD, which developed the VWF inhibitors.

Results and Conclusions: We could successfully standardize the Bethesda assay for the quantitation of VWF inhibitors in two patients with congenital type 3 VWD with inhibitors.

Successful Desensitization of a Patient with Possible IgE-Mediated Anaphylactic Reaction to FVIII/VWF Concentrate

Background: Type 3 von Willebrand disease (VWD) is a severe bleeding disorder with a prevalence of 1:1 million live births. There are several von Willebrand factor (VWF) replacement products used in the treatment of acute bleeding episodes or as prophylaxis. Patients who receive multiple transfusions have an increased risk of developing antibodies against these products. These antibodies can lead to life-threatening anaphylactic reactions. Previous studies have identified immune complex formation and complement activation as the trigger for anaphylaxis, rather than IgE. IgE-mediated anaphylaxis against VWF concentrates has not yet been published. Case: A 4-year-old female patient with type 3 VWD was referred to our hospital because of an anaphylactic reaction during FVIII/VWF concentrate (Immunate^®) infusion. She had previously received FVIII/VWF concentrate (Haemate P^®) infusions 8 times without any complications. She did not have antibodies against VWF and FVIII, and serum IgA level was normal. Since she needed factor replacement therapy as a result of a growing hematoma on her scalp, we performed skin prick and intradermal tests 2 days after the reaction. The prick test, with FVIII/VWF (Immunate), was negative, but the intradermal test was positive. We administered a 12-step desensitization protocol with FVIII/VWF concentrate (Immunate) successfully without any reactions. Conclusion: Anaphylactic reaction to factor replacement products is a major problem for patients with VWD, especially type 3 VWD requiring multiple factor infusions. We achieved a successful desensitization with FVIII/VWF concentrate in a patient who had an anaphylactic reaction during the infusion of this product. Our patient is important since she represents the first case of IgE-mediated anaphylaxis against VWF concentrate reported in the literature.

Type 3 VWD and an inhibitor to VWF: Challenges in diagnosis

Developing an inhibitor to von Willebrand factor (VWF) is extremely uncommon. Consequently, patients with von Willebrand disease (VWD) tend not to be routinely evaluated for inhibitors, leading to the possibility of delay in inhibitor diagnosis. We present such an occurrence to raise awareness, with a view to avoiding such delays. A 1-year-old male with no family history of bleeding disorders or parental consanguinity presented with a tongue bleed lasting three days. Investigations confirmed a diagnosis of Type 3 VWD. Over the next few months, the patient received seven exposures to Humate-P (a plasma derived FVIII containing von Willebrand factor concentrate), but developed an anaphylactic reaction necessitating adrenalin and Benadryl (diphenhydramine). The reaction quickly abated and did not recur with further exposure to Humate-P. In 2013, due to recurrent epistaxis and tonsillar bleeding, the patient was commenced on prophylaxis receiving Humate-P 50 RCo U/kg twice weekly. Despite this regimen, he continued to experience recurrent epistaxis, leading to escalation of prophylaxis to 3/week. In November 2014, he showed persistent tonsillar bleeding, despite having received two doses of Humate-P (each 40 RCo U/kg) in the previous 12 hours. Testing revealed reduced VWF:Ag, VWF:RCo and FVIII:C recoveries. Further testing revealed an anti-VWF antibody (2.6 BU) of unspecified Ig type. Since diagnosis of the inhibitor, he has received 100 RCo U/kg daily for prophylaxis and immune tolerance. He is now bleed-free; however, monthly inhibitor testing shows that his inhibitor persists. Given the limited experience and literature on inhibitors in VWD, the prognosis for such cases is unknown.

Laboratory monitoring of replacement therapy for major surgery in von Willebrand disease

Von Willebrand disease (VWD) is an inherited haemorrhagic disorder caused by a quantitative or qualitative defect of von Willebrand factor (VWF), a multimeric plasma glycoprotein that plays a key role in platelet adhesion to the subendothelium and acts as a carrier of factor VIII (FVIII) in blood. Patients with VWD experience bleeding symptoms that are mainly localized in mucous membranes and soft tissues, and their severity depends on the degree of the primary reduction in VWF and the secondary deficiency of FVIII in plasma. Because VWD patients are also at increased risk of perioperative bleeding, a prophylactic treatment aimed to correct the dual haemostatic defect (i.e. VWF and FVIII) is warranted. This review summarizes knowledge on the current management of patients undergoing major surgery, focusing on the peri-surgical laboratory monitoring of replacement therapy with VWF/FVIII concentrates. We suggest to monitor plasma levels of FVIII coagulant activity in the postoperative period rather than a surrogate maker of platelet-binding VWF activity as the ristocetin cofactor assay and its recent modifications.

Human von Willebrand factor/factor VIII concentrates in the management of pediatric patients with von Willebrand disease/hemophilia A

Several plasma-derived intermediate and high-purity concentrates containing von Willebrand factor (VWF) and factor VIII (FVIII) are currently available. The main role of these products in the management of the pediatric population is represented by the replacement therapy in patients with severe or intermediate forms of von Willebrand disease, in whom other treatments are ineffective or contraindicated. Another important role of VWF/FVIII concentrates in children may be their use in immune tolerance induction (ITI) protocols. ITI is particularly recommended for hemophilia A children who have developed an inhibitor against FVIII, currently the most serious complication of substitutive treatment in hemophilia. Although recombinant concentrates may represent the preferred option in children with hemophilia A, VWF/FVIII concentrates may offer an advantage in rescuing patients who failed previous ITI.

Principles of care for the diagnosis and treatment of von Willebrand disease

Von Willebrand disease is a common autosomal inherited bleeding disorder caused by quantitative or qualitative defects of von Willebrand factor, a multi-adhesive protein that binds platelets to exposed subendothelium and carries factor VIII in circulation. As a result of von Willebrand factor deficiency or abnormality, levels of factor VIII, the protein deficient in hemophilia A, may be variably reduced. Clinical manifestations are mainly represented by mucous membrane and of soft tissue bleeding. Their severity is variable depending on the degree of von Willebrand factor and factor VIII reduction. While a clear-cut diagnosis is easy in severe von Willebrand factor reductions, the advantage of pursuing a definite diagnosis in mild or dubious cases should be weighed against the risk of over-medicalization. The aim of treatment is to correct the dual defect of hemostasis caused by the abnormal/reduced von Willebrand factor and the concomitant deficiency of factor VIII. Desmopressin is the treatment of choice for type 1 von Willebrand disease patients with factor VIII and von Willebrand factor levels of 10 U/dL or over who have proved responsive to a test-infusion with the compound. Von Willebrand factor/factor VIII concentrates are needed when desmopressin is ineffective (mainly type 2 and 3 von Willebrand disease).

Alloantibodies in von Willebrand disease

The development of alloantibodies against von Willebrand factor (VWF) represents a rare but serious complication of treatment of von Willebrand disease (VWD), occurring in ~5% to 10% of type 3 VWD patients. Affected patients can present with a range of symptoms, including lack or loss of hemostatic response to infused VWF concentrates up to anaphylactic reactions in rare cases. It is classically reported in multitransfused patients and occurs most frequently in patients with partial or complete VWF gene deletions. A positive family history of anti-VWF antibodies also appears to be a risk factor. There is a lack of standardization of laboratory methods for antibody identification and characterization. Issues of variability in laboratory approaches as well as the rarity of the complication act as a barrier to future studies. Recombinant factor VIII as well as bypassing agents and immune tolerance have been reported as effective treatments; however, aside from case reports, little exists in the literature to guide management. The imminent clinical availability of recombinant VWF has prompted a resurgence of interest in this area. Additional study is warranted to address the deficiencies in our understanding of this treatment complication.

Evidence-based recommendations on the treatment of von Willebrand disease in Italy

BACKGROUND

von Willebrand disease (VWD) is the most common hereditary bleeding disorder affecting both males and females. It arises from quantitative or qualitative defects of von Willebrand factor (VWF) and causes bleeding of mucous membranes and soft tissues. The aim of treatment is to correct the dual defect of haemostasis caused by the abnormal/reduced VWF and the concomitant deficiency of factor VIII (FVIII).

MATERIAL AND METHODS

This document contains evidence-based recommendations for the management of VWD compiled by AICE (the Italian Association of Haemophilia Centres). All the evidence supporting these recommendations are based on non-randomised comparative studies or case series, because randomised controlled clinical trials or meta-analyses are not available for this disease.

RESULTS AND CONCLUSIONS

Desmopressin (DDAVP) is the treatment of choice for patients with type 1 VWD with FVIII and VWF levels of 10 U/dL or more, while VWF/FVIII concentrates are indicated for those who are unresponsive or insufficiently responsive to DDAVP (severe type 1, type 2 and 3 VWD). VWF concentrates devoid of FVIII, not yet licensed in Italy, may be considered for short-term prophylaxis in elective surgery or for long-term secondary prophylaxis.