Demographic and clinical data in acquired hemophilia A: results from the European Acquired Haemophilia Registry (EACH2)

Acquired hemophilia A: a narrative review and management approach in the emicizumab era

Acquired hemophilia A (AHA) is a rare bleeding disorder caused by inhibitory autoantibodies to factor (F)VIII. The goals of treatment are 2-fold, namely immunosuppressive therapy to eradicate the inhibitor and hemostatic management to control bleeding. Emicizumab, a bispecific antibody that acts as a FVIIIa-mimetic, has seen growing use in AHA following its approval for congenital hemophilia A. This review provides an overview of the epidemiology, pathophysiology, diagnosis, and treatment of AHA. Registry, trial, and case series data are assimilated and summarized with an emphasis on a standardized approach that integrates the use of emicizumab. With recent registry data suggesting the need to focus on immunosuppression-related mortality in AHA, we provide treatment recommendations in an algorithmic format that have become the standard of care at our institution. These recommendations are intended to minimize hemostatic product usage and potential toxicity related to immunosuppressive therapy while reducing morbidity and rehospitalization rates for bleeding. The proposed treatment algorithm, which includes key interventions by phase of therapy, can be readily implemented at centers that have rapid access to plasma FVIII activity using a one-stage assay. A case is presented to illustrate the proposed diagnostic and management considerations.

A rare case of postoperative hemorrhage following laparoscopic cholecystectomy - A case report

Laparoscopic cholecystectomy (LC) is widely accepted as the gold standard procedure for gallbladder removal. While LC is generally acknowledged for its safety and efficacy, this surgical intervention still carries the risk of complications, including postoperative hemorrhage, alongside other rare causes of bleeding. Postoperative recurrent bleeding often arises from complex underlying causes and demands swift identification and intervention for effective management. Here, we present a rare case of a patient diagnosed with an overlapping syndrome comprising primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH), along with Sjögren's syndrome (SS). This patient experienced recurrent massive hemorrhage following cholecystectomy and was ultimately diagnosed with acquired hemophilia A (AHA). We provide a detailed account of the diagnostic and management processes involved.

Acquired hemophilia A as a disease of the elderly: A comprehensive review of epidemiology, pathogenesis, and novel therapy

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder characterized by the development of neutralizing autoantibodies (inhibitors) against coagulation factor VIII (FVIII). This review provides an in-depth exploration of AHA, covering its epidemiology, pathogenesis, clinical presentation, diagnosis, complications, and treatment strategies, focusing on recent advancements. AHA can manifest in both men and women with no prior bleeding history. The annual incidence is estimated to be approximately 1 case per million individuals in the general population. The incidence increases significantly with age: the incidence among individuals aged 60 years or older is approximately 3 to 4 cases per million individuals per year. Typically, patients present with an acquired bleeding disorder that is characterized by an isolated, prolonged activated partial thromboplastin time stemming from FVIII deficiency. Diagnosis relies on the detection of neutralizing antibodies using the Nijmegen-modified Bethesda assay. Hemostatic control strategies involve bypassing agents like recombinant activated factor VII, activated prothrombin complex concentrate, and recombinant porcine FVIII for bleeding patients. Emicizumab, a novel bypassing agent, exhibits several potential advantages. In the realm of immunosuppressive treatment for inhibitor eradication, the CyDRi regimen emerged as a remarkable advancement, significantly enhancing the outlook for the management of AHA even in the elderly frail population.

Innovative Therapies for Acquired Hemophilia A

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder which can be life-threatening. AHA is due to autoantibodies against coagulation factor VIII. Disease onset may be idiopathic (approximately half of the cases) or triggered by autoimmune disorders, cancers, drugs, infections, or pregnancy. Besides treating the underlying disorder, specific AHA treatments include management of bleeding and inhibitor eradication. Various first-line and second-line hemostatic and immunosuppressive agents are currently available for the management of AHA. Recently, the hemostatic drug emicizumab and the immunosuppressive drug rituximab have been the object of intense research from investigators as innovative promising therapies for AHA. This narrative review will be focused on the current status of the clinical use of these two off-label therapeutic agents in AHA.

Real-World Data on Patients With Acquired Haemophilia A in Japan Undergoing Rehabilitation or With Low Activities of Daily Living Scores: The ORIHIME II Study

INTRODUCTION

Acquired haemophilia A (AHA) is characterized by the development of autoantibodies against factor VIII, reducing its activity and potentially resulting in bleeding.

AIM

To assess the characteristics of people with AHA undergoing rehabilitation and/or with low activities of daily living (ADL) scores, thereby characterizing unmet needs in the management of AHA and informing treatment optimization.

METHODS

ORIHIME II, the largest epidemiological and treatment survey of AHA in Japan, is a descriptive, retrospective, observational study conducted using health claims data from April 2008 to October 2021. The primary outcome measures were rehabilitation practice and ADL scores on hospital admission and discharge; use of haemostatic agents and immunosuppressive therapy were also assessed.

RESULTS

Overall, 427 patients in Japan were eligible for the study. Median (Q1-Q3) age was 78.0 (70.0-84.0) years; 264 patients (61.8%) were male. Median (Q1-Q3) time to start rehabilitation was 9 (4-21) and 14 (6-31) days for those with an admission ADL score of <85 and ≥85, respectively. Of the 427 patients, 249 underwent rehabilitation. The most common rehabilitation type was for disuse syndrome; haemostatic agents were more commonly used in patients undergoing earlier rehabilitation.

CONCLUSION

The physical condition of the patient at hospitalization was associated with rehabilitation practice and the ability of the patient to perform day-to-day activities independently. Treatment strategies should be optimized to allow initiation of rehabilitation as early as possible in the course of AHA.

Laboratory Assessment of Factor VIII Inhibitors: When Is It Required? A Perspective Informed by Local Practice

This perspective discusses the critical role of laboratory assessments in assessing factor VIII (FVIII) inhibitors. These are auto- and alloantibodies that can develop against both endogenous and exogenous FVIII, respectively. Assessment for inhibitors represents a key part of the management of both congenital hemophilia A (CHA), an inherited deficiency, and acquired hemophilia A (AHA), an autoimmune condition. Both conditions pose significant bleeding risks, necessitating careful monitoring of FVIII levels and inhibitor presence and level. Laboratory assays, particularly the Bethesda assay, are essential for detecting these inhibitors and assessing their levels. The complexities of FVIII inhibitor kinetics may pose challenges to interpretation of assay results, such that even normal FVIII levels do not always exclude inhibitor presence. Clinical practice guidelines recommend ongoing monitoring of AHA/CHA patients until inhibitors are no longer detectable. Overall, timely laboratory evaluations are essential to optimizing treatment strategies for patients with hemophilia, aiming to improve patient outcomes and quality of life. We summarize our approach to the laboratory assessment of FVIII inhibitors, as reflecting our perspective and as informed by local practice.

Role of the Hemostasis and Thrombosis Unit in the Management of Patients with Acquired Hemophilia A

Objective

Acquired hemophilia A (AHA) is a rare autoimmune disease characterized by the presence of autoantibodies against coagulation factor VIII, leading to spontaneous hemorrhage in patients without a prior family or personal history of bleeding. This study describes the demographics, diagnosis, underlying disorders, bleeding characteristics, treatment, and outcomes of 41 AHA patients together with specific case reports.

Materials and Methods

Diagnosis and treatment of these patients occurred between 2005 and 2023. The median age at diagnosis was 67.8 (range: 15-93) years. Among the 41 patients, 10 (24%) cases were idiopathic, 4 (10%) were postpartum, 18 (44%) involved autoimmune diseases, and 9 (22%) involved a diagnosis of cancer.

Results

The diagnostic delay exceeded 30 days in 15 of the 41 cases (36.5%). A total of 38 of the 41 (93%) patients presented with spontaneous bleeding, with mucocutaneous bleeding being the most common presentation (23/41, 56%). Four patients experienced postpartum bleeding. Clinical remission was achieved by 100% of patients and no patients died.

Conclusion

Hemostatic and immunosuppressive therapy is essential in AHA, and it should be started as soon as possible in patients with bleeding. However, a significant delay in diagnosis was observed in these cases. The absence of mortality is likely attributable to the management of the disease within a specialized hemostasis and thrombosis unit, which offers a clinical ward, a specialized laboratory, and a dedicated ambulatory service. The Italian Society for the Study of Haemostasis and Thrombosis is working to secure recognition of this essential role in every hospital.

Successful eradication of acquired factor VIII inhibitors with rituximab: a report of two cases

OBJECTIVES

Acquired hemophilia A (AHA) is a rare autoimmune disorder that presents with spontaneous bleeding due to the development of autoantibodies against coagulation factor VIII. This study aims to highlight the challenges in diagnosing and treating AHA, particularly through presenting two cases managed with rituximab, an anti-CD20 antibody, to demonstrate its safety and efficacy as a treatment option.

METHODS

Two male patients, aged 38 and 68, with significant bleeding episodes and prolonged activated partial thromboplastin time (aPTT), were evaluated. Both patients received standard care, including factor VIII replacement and corticosteroids. Due to persistent symptoms, rituximab was administered weekly for four weeks, and follow-up assessments were performed to monitor factor VIII levels, aPTT, and clinical symptoms.

RESULTS

Both cases showed improvement with rituximab. In Case 1, a 38-year-old male with idiopathic AHA achieved normal factor VIII levels and aPTT, with complete resolution of symptoms and no recurrence. In Case 2, a 68-year-old male with congenital hemophilia A and superimposed AHA responded positively to rituximab, showing stabilized factor VIII levels and no further bleeding episodes at a six-month follow-up.

DISCUSSION

The management of AHA is complex due to its rarity and severe bleeding risks. Although corticosteroids and bypassing agents are primary treatments, rituximab is emerging as a promising therapeutic option. Current literature supports rituximab for patients with contraindications to first-line agents or poor prognosis, yet further studies are required to assess its potential as a first-line treatment.

CONCLUSION

These cases emphasize the efficacy and safety of rituximab in managing AHA. Given its potential benefits, further randomized controlled trials are warranted to evaluate rituximab's role as a first-line treatment. A structured monitoring protocol is recommended to ensure safe administration and manage potential side effects associated with immunosuppressive therapy.

Real-world impact of emicizumab and immunosuppression on acquired hemophilia A: a multicenter US cohort

ABSTRACT

Acquired hemophilia A (AHA) is an autoimmune bleeding disorder that is caused by factor VIII (FVIII) autoantibodies with high morbidity and mortality due to bleeding and complications from immunosuppression (IST). To address the real-world implications of the FVIII mimetic antibody, emicizumab, and the role of IST, we retrospectively collected de-identified data on 62 patients with AHA who were treated off-label with emicizumab for a median of 10 weeks at 12 US-based hemophilia treatment centers. Most patients (95.2%) had acute bleeding at diagnosis, and 62.9% had partial or no control of bleeds despite the use of hemostatic agents at the time emicizumab was started. The main reason for initiating emicizumab was outpatient bleeding prophylaxis. After initiation of emicizumab, 87.1% had no additional bleeds. There were 6 breakthrough bleeds (2 spontaneous) in 5 patients and no fatal bleeding events during maintenance emicizumab treatment. The mean breakthrough bleed rate per patient-week was 0.02 (95% confidence interval, 0.0-0.03) during the first 12 weeks of emicizumab for the 55 patients with at least 12 weeks of follow-up. Of these patients, 92.7% received IST and 74.5% were prescribed rituximab-based regimens. Complete resolution of inhibitor and normalization of FVIII levels occurred in 56% overall and in 63% of the patients treated with rituximab. Overall, the median time to discontinuation of emicizumab and IST was 18 weeks. Two patients had thrombotic events while on emicizumab, but no adverse events were attributed to emicizumab and there were no infections attributed to IST. Emicizumab provides effective outpatient bleeding prophylaxis for AHA, and concurrent IST may further mitigate bleeding.

[Acquired haemophilia: Update in 2024]

Acquired hemophilia A (AHA) is a rare autoimmune disorder due to autoantibodies against factor VIII, with a high mortality risk. It should be suspected in subjects with abnormal bleedings, especially subcutaneous bleed associated with prolonged activated partial thromboplastin time (aPTT). AHA is often idiopathic but is associated with autoimmune diseases, malignancies, pregnancy and postpartum period or drugs. Treatment is based on haemostatic agents as by-passants agents such as factor VIIa and activated prothrombine concentrate complex or recombinant porcine factor VIII for severe bleeding. Eradication of inhibitor should be established as soon as the diagnosis is confirmed with steroid alone often associated with cytotoxic agents or rituximab, depending on FVIII activity and inhibitor titer. The purpose of this review is to summarize the epidemiology, etiopathogenesis, diagnosis, treatment of AHA and discuss current recommendations.

Comorbidity and adverse events in acquired hemophilia A: data from the GTH-AHA-EMI study

Background

Persons with acquired hemophilia A are often older and suffer from comorbidity or frailty. Little is known about the impact on clinically relevant outcomes of acquired hemophilia A.

Objectives

To assess the relevance of age, physical performance status, comorbidity, and concomitant medication on the risk of bleeding and other outcomes.

Methods

Post hoc analysis of data from the GTH-AHA-EMI study that used emicizumab for bleed protection and withheld immunosuppressive treatment during the early phase of management. Primary endpoint was the rate of clinically relevant new bleeding (CRNB) during the first 12 weeks of emicizumab prophylaxis.

Results

Forty-seven patients were enrolled. Median age was 76 years; performance status (World Health Organization performance status [WHO-PS]) was 3 or worse in 41%; Charlson comorbidity index (CCI) was 5 or higher in 63%; antithrombotic drugs were reported in 34%. Rate of CRNB during 12 weeks of emicizumab prophylaxis was similar across subgroups of age, sex, WHO-PS, CCI, baseline factor VIII activity, and inhibitor titer. Patients with CRNB during the study had more severe anemia already at baseline. However, persistent severe anemia in week 4 was not related to risk of bleeding beyond this time. CRNB was associated with injury from falling in 7 of 14 patients. Adverse events grade 3 or higher were not related to baseline CCI or age but were more frequent in patients with poor WHO-PS.

Conclusion

Emicizumab provided bleed protection regardless of age and comorbidity. Clinical baseline characteristics did not predict breakthrough bleeding under emicizumab. Poor WHO-PS at baseline was associated with severe adverse events during the study.

Emicizumab versus immunosuppressive therapy for the management of acquired hemophilia A

BACKGROUND

Acquired hemophilia A (AHA) is an autoimmune bleeding disorder caused by neutralizing antibodies against coagulation factor VIII. Immunosuppressive therapy (IST) is standard of care to eradicate autoantibody production and protect from further bleeding but carries a risk of severe infection and mortality in frail patients with AHA. Recently, emicizumab has been studied for its potential to reduce the need for early and aggressive IST.

OBJECTIVES

To compare outcomes of 2 studies that used either IST (GTH-AH 01/2010; N = 101) or prophylaxis with emicizumab (GTH-AHA-EMI; N = 47) early after diagnosis of AHA.

METHODS

Baseline characteristics were balanced by propensity score matching. Primary endpoint was the rate of clinically relevant new bleeds during the first 12 weeks; secondary endpoints were adverse events and overall survival.

RESULTS

The negative binominal model-based bleeding rate was 68% lower with emicizumab as compared with IST (incident rate ratio, 0.325; 95% CI, 0.182-0.581). No difference was apparent in the overall frequency of infections (emicizumab 21%, IST 29%) during the first 12 weeks, but infections were less often fatal in emicizumab-treated patients (0%) compared with IST-treated patients (11%). Thromboembolic events occurred less often with emicizumab (2%) than with IST (7%). Overall survival after 24 weeks was better with emicizumab (90% vs 76%; hazard ratio, 0.44; 95%, CI, 0.24-0.81).

CONCLUSION

Using emicizumab instead of IST in the early phase after initial diagnosis of AHA reduced bleeding and fatal infections and improved overall survival.

Efficacy and safety of recombinant porcine factor VIII in Japanese patients with acquired hemophilia A

Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies inhibiting human factor VIII (hFVIII). This phase II/III open-label study evaluated the safety and efficacy of recombinant porcine factor VIII (rpFVIII, susoctocog alfa) in adults with AHA and severe bleeding episodes in Japan (NCT04580407). The initial rpFVIII dose was 200 U/kg, with subsequent doses based on clinical measures including plasma FVIII activity. The primary efficacy endpoint was the proportion of severe bleeding episodes with a positive response to rpFVIII therapy 24 h after treatment initiation. Five patients were eligible for, and completed, rpFVIII treatment (age group: 60s-80s; median hFVIII inhibitor: 52 BU/mL; porcine FVIII [pFVIII] inhibitor: 3/5 patients). The median (range) total dose/patient was 548.4 (198-1803) U/kg with a median 3.0 infusions/patient. All patients responded positively to rpFVIII therapy at 24 h regardless of baseline pFVIII inhibitor status. rpFVIII treatment was well tolerated with no adverse events of special interest such as thromboembolic events or de novo pFVIII inhibitors. This study supports the use of rpFVIII as a novel therapy in the clinical management of patients with AHA in Japan. rpFVIII was approved for treating bleeding episodes in adults with AHA in Japan in 2024.

Final Analysis Results from the AGEHA Study: Emicizumab Prophylaxis for Acquired Hemophilia A with or without Immunosuppressive Therapy

BACKGROUND

 Primary analysis of the phase III AGEHA study suggested a favorable benefit-risk profile for emicizumab prophylaxis in patients with acquired hemophilia A (PwAHA); however, only patients undergoing immunosuppressive therapy (IST; Cohort 1) were included.

OBJECTIVES

 To present final analysis results of AGEHA, including data on IST-ineligible patients (Cohort 2) and on long-term prophylaxis with emicizumab.

METHODS

 For patients in both Cohorts 1 and 2, emicizumab was administered subcutaneously at 6 mg/kg on Day 1, 3 mg/kg on Day 2, and 1.5 mg/kg once weekly from Day 8 onward.

RESULTS

 Twelve patients (Cohort 1) and two patients (Cohort 2) were enrolled. Duration of emicizumab treatment was 8 to 639 days (median: 44.5 days) in Cohort 1 and 64 and 450 days in Cohort 2. In both cohorts, no major bleeds were observed after initial emicizumab administration. Six patients started their first rehabilitation sessions during emicizumab treatment and no rehabilitation-related bleeds occurred. Twenty-three surgeries were performed under emicizumab prophylaxis and there were no bleeds related to surgeries. Although asymptomatic deep vein thrombosis was reported in one patient in the primary analysis, no other thrombotic events occurred thereafter. Two patients developed anti-emicizumab antibodies, one of whom showed accelerated emicizumab clearance. Tailored IST approaches (delayed initiation, no use, or reduced dose) were successfully executed in three patients undergoing emicizumab prophylaxis.

CONCLUSION

 These results suggest that emicizumab prophylaxis has a favorable benefit-risk profile in PwAHA regardless of eligibility for IST.

Acquired haemophilia A in Finland: A nationwide study of incidence, treatment and outcomes

INTRODUCTION

Acquired haemophilia A (AHA) is a bleeding disorder caused by autoantibody development against factor VIII (FVIII). Studies on AHA have mainly focused on patients treated at specialist centres.

AIM

To determine the incidence, clinical characteristics and outcomes of AHA in an unselected population-based patient cohort from Finland.

METHODS

This retrospective observational cohort comprised all cases diagnosed with AHA in Finland between 2006 and 2019. Patients were identified by the two central laboratories performing FVIII antibody testing in Finland, the Finnish Red Cross Blood Service and HUSLAB. Clinical details were collected from all hospitals and healthcare units where patients were treated. This study was performed in conjunction with the AHA in the Nordics study.

RESULTS

The median incidence of AHA was 0.65 per million per year (range 0.19-1.27). Fifty-five patients were identified, with a median age of 76 years and an even sex ratio (51% women). When diagnosed, all had bleeding symptoms with severe bleeds in 92%. First-line immunosuppressive treatment regimens included steroid monotherapy in 31% of cases, steroids and a cytotoxic agent in 51% and a rituximab-based regimen in 16%. Clinical remission was achieved in 71% of cases, and 15% had relapses. Mortality was 13% for bleeds and 9% for treatment-related infections. Overall survival was 64% for 1 year and 56% for 2 years after diagnosis.

CONCLUSIONS

In a nationwide population-based cohort study, we discovered a lower incidence of AHA than previously reported. Mortality among patients with AHA was high, calling for the consideration of updated treatment strategies.

Unravelling Acquired Hemophilia A in an Ambiguous Clinical Picture

Acquired hemophilia A (AHA) is characterized by the development of neutralizing autoantibodies, called "inhibitors," against intrinsic factor VIII. Its presentation differs profoundly from congenital hemophilia. Here, we present the case of a 69-year-old patient presenting with right-sided flank pain and hematuria, initially diagnosed with acute pyelonephritis, who was found to have bilateral renal hemorrhage during the course of his hospitalization. Later, after a thorough diagnostic evaluation, he was deemed to have AHA.

Acquired Hemophilia A Diagnosed Based on Gross Hematuria: A Case Report and Literature Review

Acquired hemophilia A (AHA) is an acquired bleeding disorder caused by neutralizing antibodies (inhibitors) against Coagulation Factor VIII (FVIII:C), causing sudden hemorrhagic symptoms (i.e., subcutaneous bleeding, intramuscular bleeding, and hematuria). Herein, this study is aimed at presenting a case of AHA diagnosed based on hematuria and reviewing patients who were diagnosed with AHA due to hematuria. A 67-year-old woman was referred to Atsugi City Hospital with painless gross hematuria that began 4 weeks before presentation. Contrast-enhanced computed tomography (eCT) revealed an approximately 2 cm mass in the right renal pelvis, and the patient's activated partial thromboplastin time (APTT) was elevated (61.4 s). The day after the endoscopic biopsy, the patient was in shock due to a large retroperitoneal hematoma. Although her condition stabilized after intravenous radioembolization, she underwent emergency surgeries several times because of rebleeding within the next 3 weeks. At that time, APTT was more prolonged at 106.4 s, and the FVIII:C level was 2%. Mixing tests showed an upwardly convex curve after 2-h incubation, indicating the presence of an inhibitor. Factor VIII inhibitor titer was ≥5.1 Bethesda unit (BU)/mL. A combined product of Plasma-Derived Factors VIIa and X (pd-FVIIa/FX), as second-line hemostatic therapy, as well as cyclophosphamide (CYP), were administered after Recombinant Activated Factor VIIa (rFVIIa) had been ineffective. Following this, the Factor VIII inhibitor titer was undetectable, FVIII:C levels were restored, and APTT decreased to within the normal range. Gross hematuria was significantly alleviated. However, the patient died of cytomegalovirus and fungal infections due to prolonged immunosuppressive therapy. Although AHA diagnosed based on hematuria may have a better prognosis than others, there have been occasional cases with severe outcomes. APTT, detected upon initial hematological testing in patients with hematuria, may be a potential indicator of an existing AHA.

Severe acquired hemophilia A associated with COVID-19 vaccination: A case report and literature review

RATIONALE

Acquired hemophilia A (AHA) is a rare autoimmune disease caused by an antibody that inhibits coagulation factor VIII activity. More than half of patients with AHA cannot identify underlying disorders. The remaining patients are associated with malignancies, autoimmune diseases, skin diseases, infections, and medications. Here, we present a case of 56-year-old Korean man with underlying hypertension, dyslipidemia, and diabetes mellitus who developed AHA following the second dose of BNT162b2 COVID-19 vaccination.

PATIENT CONCERNS

He presented with a large 20 × 30 cm-sized hematoma along the psoas muscle and intracranial hemorrhage, necessitating intensive care with mechanical ventilation and continuous renal replacement therapy. Laboratory testing demonstrated that activated partial thromboplastin time and prothrombin times were 74.7 seconds (normal range 29-43 seconds) and 17.2 seconds (normal range 12.5-14.7 seconds), respectively.

DIAGNOSES

Laboratory tests confirmed AHA with undetectable factor VIII activity (<1.5%) and a positive factor VIII antibody with a titer of 8.49 Bethesda units/mL.

INTERVENTIONS

Recombinant factor VIIa (NovoSeven®) was administered every 2 hours to control the bleeding, alongside immunosuppression with methylprednisolone 1 mg/kg daily and cyclophosphamide 2 mg/kg daily to eliminate the autoantibody.

OUTCOMES

Despite the treatments, the patient developed sepsis and succumbed 14 weeks after admission.

LESSONS

This rare case underscores the importance of monitoring for AHA following COVID-19 vaccination. Although the benefits outweigh the risks of vaccination, AHA should be considered in the differential diagnosis of unusual bleeding following the vaccinations. Early diagnosis and management before severe bleeding are critical for successfully controlling life-threatening bleeding.

Retrospective study of the clinical manifestations and efficacy of immunotherapy for patients with acquired hemophilia A

OBJECTIVE

Raising awareness of acquired hemophilia A (AHA) and early diagnosis is critical to reduce the associated mortality rate. We aimed to characterize acquired hemophilia in Chinese patients and evaluate the effectiveness of immunotherapy.

METHODS

The clinical characteristics, laboratory test data, therapeutic approaches, and outcomes of 20 patients with AHA who were admitted to Xi'an Central Hospital between January 2012 and December 2020 were retrospectively studied.

RESULTS

Nine of the patients (45%) were treated by single glucocorticoid administration; three (15%) with cyclophosphamide (CP) in combination with a glucocorticoid; four individuals (20%) received a combination therapy of rituximab with CP and glucocorticoid or rituximab with CP, vincristine, and a glucocorticoid; three (15%) by injection of human immunoglobulin in combination with a glucocorticoid; and one (5%) with CP alone. Six patients (30%) achieved total remission and 11 (55%) partial remission (PR), but three (15%) did not enter remission, indicating an objective response rate of 85%.

CONCLUSION

Combination therapy with rituximab or intravenous human immunoglobulin achieves superior results in some patients with AHA. Immunosuppression and the administration of coagulation factors can rapidly control the disease and are efficacious, but >50% of patients only achieved PR. These findings suggest that the complete elimination of inhibitors requires prolonged immunosuppression therapy.

Acquired Hemophilia A after SARS-CoV-2 Immunization: A Narrative Review of a Rare Side Effect

Acquired hemophilia A (AHA) is a rare bleeding disorder (1.4 per million inhabitants per year) caused by neutralizing antibodies against factor VIII. Although uncommon, these autoantibodies can cause a high rate of morbidity and mortality. Several conditions are linked with AHA; based on an EACH2 study, 3.8% of AHA could be connected to infection. In the last four years, most humans have contracted the SARS-CoV-2 infection or have been vaccinated against it. Whether or not COVID-19 immunization might induce AHA remains controversial. This review aims to evaluate the evidence about this possible association. Overall, 18 manuscripts (2 case series and 16 case reports) were included. The anti-SARS-CoV-2 vaccination, as also happens with other vaccines, may stimulate an autoimmune response. However, older individuals with various comorbidities are both at risk of developing AHA and of COVID-19-related morbidity and mortality. Therefore, the COVID-19 vaccine must always be administered because the benefits still outweigh the risks. Yet, we should consider the rare possibility that the activation of an immunological response through vaccination may result in AHA. Detailed registries and prospective studies would be necessary to analyze this post-vaccine acquired bleeding disorder, looking for possible markers and underlying risk factors for developing the disease in association with vaccination.

Inhibitor eradication and treatment for acquired hemophilia A

INTRODUCTION

Acquired hemophilia A (AHA) is a rare hemorrhagic autoimmune disorder characterized by autoantibodies against coagulation factor VIII (FVIII). In approximately half of the cases AHA does not recognize any cause (idiopathic form), while in the other cases it may be triggered by autoimmune disorders, cancers, drugs, infections, or pregnancy. Besides treating the underlying disorder, specific AHA treatment includes management of bleeding, if necessary, and inhibitor eradication.

AREAS COVERED

This narrative review summarizes the main epidemiological, clinical, laboratory, and therapeutic characteristics of AHA. In particular, it is focused on the current therapeutic options for the inhibitor eradication, also showing the latest findings on the innovative therapies. A literature search strategy was performed, without temporal limits, through Medline and PubMed electronic databases.

EXPERT OPINION

Various first-line and second-line immunosuppressive agents are currently available for the management of AHA. Among the latter, the anti-CD20 monoclonal antibody rituximab has been the object of intense research during the last years from investigators as innovative promising eradicating therapy for AHA. Preliminary data from the studies support the use of this drug as a first-line option for newly diagnosed AHA cases.

Association of bullous pemphigoid with acquired hemophilia A: a case report

Acquired hemophilia A, a rare condition resulting in spontaneous bleeding without prior bleeding disorders, arises due to autoantibody-mediated inhibition of coagulation factor VIII and is typically associated with autoimmune, neoplastic, drug, or obstetric factors. We present the case of a 31-year-old woman with bullous pemphigoid, managed with corticosteroids since 2013, who presented spontaneous hemorrhagic manifestations. Upon admission, laboratory tests revealed hypochromic microcytic anemia, prolonged activated partial thromboplastin time, and a factor VIII level < 1%, indicative of acquired hemophilia A. Further assessments showed elevated Ristocetin cofactor activity, von Willebrand factor antigen, and a factor VIII inhibitor level of 665 BU. This underscores the importance of considering acquired hemophilia A in autoimmune dermatological conditions like bullous pemphigoid, highlighting the association between autoimmune disorders and coagulation abnormalities, particularly in cases of spontaneous hemorrhagic events.

Genetics and Epigenetics in Acquired Hemophilia A: From Bench to Bedside

Acquired hemophilia A (AHA) is a bleeding disorder characterized by the immunological inhibition of factor VIII (FVIII) of the hemostatic pathway leading to hemorrhagic events. Different domains of FVIII are the target of autoantibodies (mainly immunoglobulin (Ig) G) leading to the deficiency of FVIII. Several factors have been associated with the activation of the auto-immunity towards FVIII. Emerging evidence implicates CD4+ T cell activation in mediating this autoimmune response, with their involvement like that observed in congenital hemophilia A. Several genes such as HLA II DRB*16, DQB1*0502, and CTLA-4 + 49 are responsible for the pathogenesis of AHA. Epigenetic modifications and mainly long-coding RNAS (lncRNAs) are potentially contributing to the pathogenesis of AHA. The treatment approach of AHA includes the management of acute bleeding events and the administration of immunosuppressive medications. This review aimed to summarize the published data on the genetics and epigenetics of AHA. The severity and the mortality of this disease are creating an emerging need for further research in the field of the genetics and epigenetics of acquired hemorrhagic disorder.

Case Report: Effective management of adalimumab-induced acquired hemophilia A with the CyDRI protocol

Introduction

Acquired Hemophilia A (AHA) is a rare autoimmune disorder characterized by the emergence of inhibitors that specifically target coagulation Factor VIII, frequently resulting in severe bleeding episodes.

Methods

We conducted a retrospective analysis of the medical records of a 68-year-old male patient who presented with adalimumab-induced AHA.

Results

The patient received adalimumab, a tumor necrosis factor inhibitor antibody, as part of his treatment for rheumatoid arthritis. The patient's clinical journey, characterized by intense bleeding and coagulopathy, was effectively managed with the application of recombinant Factor VIIa (rFVIIa) and the CyDRi protocol.

Discussion

The case emphasizes the importance of prompt coagulation assessment in patients with bleeding symptoms receiving disease-modifying therapy for rheumatoid arthritis that includes adalimumab therapy, considering the rare yet life-threatening nature of AHA. Additionally, this report provides an extensive review of the existing literature on drug-induced AHA, with a special emphasis on cases linked to immunomodulatory medications. Through this two-pronged approach, our report aims to enhance understanding and awareness of this severe complication among healthcare providers, promoting timely diagnosis and intervention.

Cyclophosphamide vs rituximab for eradicating inhibitors in acquired hemophilia A: A randomized trial in 108 patients

BACKGROUND

Acquired hemophilia A (AHA) is a rare autoimmune disorder due to autoantibodies against Factor VIII, with a high mortality risk. Treatments aim to control bleeding and eradicate antibodies by immunosuppression. International recommendations rely on registers and international expert panels.

METHODS

CREHA, an open-label randomized trial, compared the efficacy and safety of cyclophosphamide and rituximab in association with steroids in patients with newly diagnosed AHA. Participants were treated with 1 mg/kg prednisone daily and randomly assigned to receive either 1.5-2 mg/kg/day cyclophosphamide orally for 6 weeks, or 375 mg/m2 rituximab once weekly for 4 weeks. The primary endpoint was complete remission over 18 months. Secondary endpoints included time to achieve complete remission, relapse occurrence, mortality, infections and bleeding, and severe adverse events.

RESULTS

Recruitment was interrupted because of new treatment recommendations after 108 patients included (58 cyclophosphamide, 50 rituximab). After 18 months, 39 cyclophosphamide patients (67.2 %) and 31 rituximab patients (62.0 %) were in complete remission (OR 1.26; 95 % CI, 0.57 to 2.78). In the poor prognosis group (FVIII < 1 IU/dL, inhibitor titer > 20 BU mL-1), significantly more remissions were observed with cyclophosphamide (22 patients, 78.6 %) than with rituximab (12 patients, 48.0 %; p = 0.02). Relapse rates, deaths, severe infections, and bleeding were similar in the 2 groups. In patients with severe infection, cumulative doses of steroids were significantly higher than in patients without infection (p = 0.03).

CONCLUSION

Cyclophosphamide and rituximab showed similar efficacy and safety. As first line, cyclophosphamide seems preferable, especially in poor prognosis patients, as administered orally and less expensive.

FUNDING

French Ministry of Health.

CLINICALTRIALS

gov number: NCT01808911.

Acquired bleeding disorders

Acquired bleeding disorders can develop in previously healthy people irrespective of age or gender but are particularly common in patients with certain underlying conditions. Here, we review recent advances in the management of acquired haemophilia A (AHA), acquired von Willebrand syndrome (AVWS), and patients with hemostatic abnormalities due to chronic liver disease (CLD). Patients with AHA can now benefit from prophylaxis with emicizumab, a therapeutic antibody that mimics the function of activated coagulation factor VIII. The treatment of AVWS remains challenging in many situations and requires careful consideration of the underlying condition. Haemostatic abnormalities in CLD are often compensated by proportional reduction in pro and anti-haemostatic factors resulting in sustained or even increased thrombin generation. Consequently, bleeding in CLD is rarely caused by haemostatic failure and infusion of plasma or coagulation factor concentrates may not be effective.

Severe case of postpartum-acquired haemophilia A after laparoscopic cholecystectomy

Acquired factor VIII inhibitor, also known as acquired haemophilia A, has been associated with the postpartum state in young females. Treatment of acquired haemophilia A is focused on two goals: control of bleeding and eliminating the factor VIII inhibitor. Management requires successful intervention to accomplish both goals. Here, we describe the presentation and management of a case of acquired haemophilia A resulting in particularly severe and protracted intra-abdominal bleeding after routine laparoscopic cholecystectomy in a young and otherwise healthy female at 3 months postpartum. Due to diffuse intra-abdominal bleeding, she required return to the operating room on five occasions for intra-abdominal packing, reassessment of bleeding and ultimate fascial closure. Her abdomen was open for 5 days. She was treated with activated recombinant human factor VIIa to bypass inhibited factor VIII, and with immunosuppression using steroids, cyclophosphamide and anti-CD20 monoclonal antibody rituximab. She achieved remission after 6 weeks of treatment.

Anti-Thrombin IgA in a Patient with Multiple Myeloma Leading to In Vitro Interference in Multiple Coagulation Tests and Confounding Diagnosis

BACKGROUND

 We report the case of a 59-year-old multiple myeloma patient in whom an anti-human thrombin IgA antibody led to prolonged in vitro coagulation times, suggesting inhibitors to all intrinsic coagulation factors in the absence of spontaneous bleeding.

METHODS

 Routine and extensive special coagulation tests, in vivo bleeding time, and specific antibody testing were performed.

RESULTS

 Although the patient did not suffer from spontaneous bleeding and had a normal in vivo bleeding time, the anti-human thrombin IgA autoantibody affected all coagulation assays involving human thrombin in vitro, mimicking inhibitors to intrinsic coagulation factors. As the IgA paraprotein and the IgA antibody virtually disappeared after autologous stem cell transplantation, the coagulation tests also largely normalized.

CONCLUSION

 Antibodies to human thrombin may interfere with all coagulation assays involving thrombin, imitating a severe coagulopathy. However, in vivo they do not necessarily lead to strongly increased bleeding tendency. Complex and ambiguous coagulation abnormalities should be evaluated and treated in an interdisciplinary setting, including a highly specialized coagulation laboratory, from the beginning.

Acquired haemophilia A in paediatric patients: A retrospective French cohort of eight cases

Acquired haemophilia A (AHA) is a rare haemorrhagic disease characterised by new-onset haemorrhagic symptoms associated with a dramatic decrease in factor VIII levels and an anti-factor VIII neutralising autoantibody concentration >0.6 Bethesda units. Elderly people are often affected, whereas children are rarely affected; the paediatric incidence reported in the literature is about 0.045 case/million/year. For some time, the paediatric standard of care has been that for adults, but clinicians have often reported poor outcomes. Here, we describe the largest retrospective paediatric AHA cohort assembled to date, including eight patients diagnosed in France from 2000 to 2020.

Relapse of Acquired Hemophilia A after COVID-19 Infection

Acquired hemophilia A (AHA) is a rare disease in which an autoantibody causes bleeding by interacting with and inhibiting the coagulation activity of endogenous factor VIII (FVIII). Most cases of AHA are idiopathic; known causes include autoimmune diseases, malignant tumors, pregnancy, drugs, and viral infections. An 86-year-old man was diagnosed with AHA based on the following results: an activated partial thromboplastin time (aPTT) extension of 130.7 seconds, presence of an inhibitor pattern in a mixing study, an endogenous factor VIII (FVIII) level of <1%, and an FVIII inhibitor titer of >5.1 Bethesda units (BU). The activity of von Willebrand factor (vWF) was diminished (<10%), which was considered a complication of acquired von Willebrand syndrome (AVWS). The patient was started on prednisolone, and the inhibitor level eventually became negative. vWF values also became normal. However, 1 year later, he was hospitalized for treatment of coronavirus disease 2019 (COVID-19). Blood testing showed an aPTT extension of 110.5 seconds, FVIII level of 4%, and FVIII inhibitor titer of 0.8 BU; thus, a relapse of AHA was diagnosed. After administration of corticosteroid and remdesivir, he recovered from COVID-19 and AHA. The inhibitor level became negative on the 9th day of admission. Several studies have implicated COVID-19 infection and vaccination in AHA. We recommend that aPTT be measured when patients with AHA are infected with SARS-CoV2, to confirm AHA relapse.

Acquired hemophilia A: a single-center study of 165 patients

Background

Acquired hemophilia A (AHA) is a rare hemorrhagic disorder caused by factor (F)VIII inhibitors. The diagnosis and management of AHA remains challenging because of its rarity and heterogeneity.

Objectives

To analyze the characteristics of AHA to enhance our understanding of this disease and identify effective treatment strategies. To analyze the characteristics of AHA to enhance our understanding of this disease and identify effective treatment strategies.

Methods

Clinical features of 165 patients with AHA from a single center between July 1997 and December 2021 were retrospectively analyzed.

Results

The median age of patients at diagnosis was 45 years. The median time to diagnosis was 30 days. All 165 patients experienced bleeding, with a median bleeding score (BS) of 4 (range, 2-12). Hemostatic therapy was administered to 129 (78.2%) patients. Bleeding control was achieved in 80.0% of patients who received prothrombin complex concentrate and in 92.3% of patients who were treated with recombinant activated FVII. Of the 163 patients who received immunosuppressive therapy, 80 (49.1%) received rituximab-based therapy with a 93.3% complete remission (CR) rate, 50 (30.7%) received steroids plus cyclophosphamide with an 85.0% CR rate, and 22 (13.5%) received steroids alone with an 82.4% CR rate. Six cases relapsed after a median duration of 330 days. Immunosuppressive therapy-related adverse events were reported in 17 patients. Seven deaths were recorded. FVIII inhibitor titer of ≥15 BU/mL and BS of ≥6 were identified as significantly poor prognostic factors for CR.

Conclusion

Immunosuppressive therapies yield remarkably high response rates, with a CR rate exceeding 80%; notably, the regimen containing rituximab exhibits a CR rate of approximately 90%. FVIII inhibitor titer of ≥5 BU/mL and BS of ≥6 were poor predictors of CR in patients with AHA.

Characteristics and outcome of a territory-wide cohort study of patients with acquired hemophilia A in Hong Kong

INTRODUCTION

Acquired hemophilia A (AHA) is a rare bleeding disorder with destruction of factor VIII by autoantibodies. Comprehensive data for Chinese patients are lacking. Predictors of hospital stay have not been investigated.

METHODS

A territory-wide review of patients diagnosed with AHA from January 1, 2012, to December 31, 2021 was performed by retrieving patients' information from an electronic database system in Hong Kong.

RESULTS

Overall, 165 patients were included in this 10-year study, and the estimated incidence was 2.4 per million/year, which was higher than those reported from Caucasian cohorts. The median age of diagnosis was 80 years old. Patients had a long hospital stay (median: 25 days) and high mortality (55.2 %). The majority of deaths were caused by immunosuppression-related sepsis (49.5 %). Age was an independent predictor of overall survival (Hazard ratio: 1.065, 95 % CI: 1.037-1.093, p < 0.001), complete remission (CR) status (odd ratios (OR): 0.948, 95 % CI: 0.921-0.976, p < 0.001) and time to achieve CR (OR: 1.043, 95 % CI: 1.019-1.067, p < 0.001). Higher hemoglobin level on presentation was associated with shorter time to achieve CR (OR: 0.888, 95 % CI: 0.795-0.993, p = 0.037). Factor VIII level < 1 % normal, high inhibitor titer and intensive immunosuppressive regimen predicted long hospital stay.

CONCLUSION

We presented comprehensive data of Chinese patients with AHA which comprised predominantly frail elderly who required long hospital stay and had high sepsis-related mortality. This posed challenges in managing AHA in such patients. Individualized immunosuppressive therapy is needed to balance the benefits and risk of septic complications.

Mice possess a more limited natural antihuman factor VIII antibody repertoire than humans that is produced disproportionately by marginal zone B cells

BACKGROUND

One-third of patients with severe hemophilia A develop neutralizing antibodies to the factor VIII (FVIII) protein in response to intravenous replacement therapy. Patients may also generate natural, nonneutralizing antibodies to FVIII before FVIII exposure. These patients are at increased risk of developing neutralizing antibodies to FVIII. However, natural anti-FVIII antibodies are also present in healthy human donors.

OBJECTIVES

To further characterize the natural antihuman (h) FVIII antibody repertoire in mice and humans.

METHODS

An in-house ELISA was developed using a purified polyclonal immunoglobulin (Ig) standard to quantify anti-hFVIII Ig in cell culture supernatant or plasma from mice (wild-type and FVIII-/-) and adult human donors.

RESULTS

All naïve wild-type and FVIII-/- mice, as well as healthy human donors, possess natural anti-hFVIII antibodies. Mice only have natural anti-hFVIII IgM, which is present in germ-free mice, suggesting that they are germline encoded. Although murine marginal zone B cells (MZBs) contribute 44% to all circulating natural IgM, they contribute disproportionately to the anti-hFVIII IgM repertoire (82%). This naturally occurring murine MZB-derived IgM is not B-domain specific and is reduced by intravenously administered hFVIII, suggesting that it may form immune complexes immediately upon hFVIII administration. Natural anti-hFVIII antibodies of IgG, IgM, and IgA isotypes can be detected in adult human donors. There were increased levels of B-domain-favoring anti-hFVIII IgG in 14% of healthy donors, which were markedly different from the rest of the "low-titer" population.

CONCLUSIONS

There is a preponderance of natural anti-hFVIII antibodies in both mice and healthy adult human donors.

Outcomes of Emicizumab in Acquired Hemophilia Patients: A Systematic Review

BACKGROUND

Emicizumab, a bispecific factor VIII mimetic antibody, was approved in 2018 for bleeding prophylaxis in congenital hemophilia A with or without inhibitors. Since then, several case reports and case series have described the off-label use of emicizumab in acquired hemophilia A (AHA), and data from two clinical trials were recently published (AGEHA, GTH-AHA-EMI).

OBJECTIVES

To describe the reported data on the outcomes of emicizumab, highlighting its benefit/risk profile in treatment.

METHODS

We conducted a literature search in PubMed, Scopus, Cochrane, and Google Scholar up to August 2024, including all scientific articles reporting clinical outcomes of emicizumab use in patients with AHA.

RESULTS

Thirty-two studies were included in the final review, covering a total of 171 AHA patients. The majority started emicizumab for active bleeding management and prophylaxis with various regimens. Follow-up duration and remission criteria varied. Two clinical trials supported the use of emicizumab for bleeding prophylaxis with a new dosing regimen and completion criteria. Bleeding was well managed in all cases, with no major recurrent bleeds. Some adverse events were reported : 3 cases of deep venous thrombosis, 2 cases of stroke, and 2 cases of anti-emicizumab drug antibodies developing in patients with thromboembolic risk factors.

CONCLUSIONS

Based on published data, emicizumab appears to be effective in bleeding management and prophylaxis in AHA patients, with a favorable benefit/risk profile.

Single-dose rituximab plus glucocorticoid versus cyclophosphamide plus glucocorticoid in patients with newly diagnosed acquired hemophilia A: A multicenter, open-label, randomized noninferiority trial

Acquired hemophilia A (AHA) is a rare but serious bleeding disorder. Randomized controlled trial (RCT) comparing the efficacy of immunosuppression therapy for AHA lacks. We conducted the first multicenter RCT aiming to establish whether the single-dose rituximab combination regimen was noninferior to the cyclophosphamide combination regimen. From 2017 to 2022, 63 patients with newly diagnosed AHA from five centers were randomly assigned 1:1 to receive glucocorticoid (methylprednisolone 0.8 mg/kg per day for the first 3 weeks and then tapered) plus single-dose rituximab (375 mg/m2 ; n = 31) or plus cyclophosphamide (2 mg/kg per day until inhibitor becomes negative, for a maximum of 5 weeks; n = 32). The primary outcome was complete remission (CR, defined as FVIII activity ≥50 IU/dL, FVIII inhibitor undetectable, immunosuppression tapered and no bleeding for 24 h without bypassing agents) rate measured within 8 weeks. The noninferiority margin was an absolute difference of 20%. Twenty-four (77.4%) patients in the rituximab group and 22 (68.8%) patients in the cyclophosphamide group achieved CR, which showed the noninferiority of the single-dose rituximab-based regimen (absolute difference = -8.67%, lower limit of the 95% confidence interval = -13.11%; Pnoninferiority = 0.005). No difference was found in the incidence of treatment-related adverse events. Single-dose rituximab plus glucocorticoid regimen showed similar efficacy and safety, without a reported risk of secondary malignancies or reproductive toxicity seen in cyclophosphamide, it might be recommended as a first-line therapy for AHA, especially in China where there is a young age trend in AHA patients. This trial was registered at ClinicalTrials.gov as #NCT03384277.

Hematological Complications in a COVID-19 Patient: A Case Report

Hemophilia A is a hemorrhagic disorder caused by insufficient or inadequate coagulation factor VIII activity. Two different forms are described: congenital, hereditary X-linked, and acquired. Acquired hemophilia A (AHA) is a rare condition and it is defined by the production of autoantibodies neutralizing factor VIII, known as inhibitors. We report the case of a 72-year-old man with a clinical diagnosis of AHA after SARS-CoV-2 infection, which has been described in association with several hematological complications. SARS-CoV-2 infection could represent the immunological trigger for the development of autoantibodies. In our patient, SARS-CoV-2 infection preceded the hemorrhagic complications by 15 days. This lag time is in line with the other cases reported and compatible with the development of an intense immune response with autoantibody production. It is possible that since our patient was affected by type 1 diabetes mellitus, he was more prone to an immune system pathological response against self-antigens. A prompt, appropriate therapeutic intervention with activated recombinant factor VII administration and cyclophosphamide has led to rapid remission of clinical and laboratory findings.

The role of emicizumab in acquired hemophilia A

Acquired hemophilia is a rare bleeding disorder that predominantly affects older people with potential underlying comorbidities, including cardiovascular and thrombotic risk factors. The current standard therapies with hemostatic agents for acute bleeding and immunosuppression often require inpatient management, are not approved for routine bleeding prophylaxis, and contribute to the high mortality in this population. Emicizumab is a factor VIII (FVIII) mimetic approved for bleeding prophylaxis in congenital hemophilia A with and without FVIII inhibitors. Given subcutaneously, it may allow easier outpatient bleeding prophylaxis and reduce intensity of immunosuppression. This article summarizes the currently available data on the efficacy and safety of emicizumab in acquired hemophilia A.

Diagnosis and laboratory monitoring of acquired hemophilia A

Acquired hemophilia A (AHA) is a rare disorder in which autoantibodies against factor VIII (FVIII) lead to a bleeding phenotype that varies from life-threatening to no bleeding at all. Prolonged activated partial thromboplastin times (APTT) in patients with a bleeding phenotype should be investigated to rule out AHA and should never be ignored in a preprocedure patient. Most inhibitors in AHA are heat and time dependent, so mixing studies performed only on an immediate mix are not useful: both lupus anticoagulants and treatment with direct oral anticoagulants can coexist with AHA and confound the diagnosis. Assays for intrinsic coagulation factors and von Willebrand factor should always be performed, regardless of the results of mixing studies. A Bethesda or modified Bethesda assay should be performed to quantify any inhibitor, and if susoctocog alfa (rpFVIII) is available, then an assay for cross-reacting antibodies should also be performed. At diagnosis and until complete remission, if the FVIII in the patient sample is >5 IU/dL, heat inactivation should be performed before the inhibitor assays are performed. While there are no conventional tests available to measure the effects of FVIII bypassing therapies, newer therapies may require monitoring, or their effects may need to be considered when choosing appropriate assays. Measurement of rpFVIII requires a 1-stage clotting assay, and measurement of patient FVIII while on emicizumab requires a chromogenic assay that does not contain human FX. Close communication is required between the treating clinicians and the laboratory to ensure that the correct tests are performed while patients are receiving treatments.

Diagnostic Challenges and Management of Acquired Hemophilia A Presenting as Gross Hematuria: A Case Report

Acquired hemophilia A (AHA) is a rare autoimmune disorder marked by autoantibodies against coagulation factor VIII, leading to bleeding complications. This case report explores a unique presentation of AHA, initially manifested as gross hematuria, a symptom often encountered in healthcare settings with a broad range of differential diagnoses. The background of this study highlights the rarity of AHA and its diverse clinical presentations. The case involves a 62-year-old man with no history of bleeding disorders, presenting with gross hematuria and later developing severe anemia and ecchymoses. Methods employed in the evaluation included urological assessments such as cystoscopy and computed tomography, alongside hematological investigations, which later revealed a prolonged activated partial thromboplastin time (aPTT) and a critically low factor VIII level, indicative of AHA. Results showed a lack of early recognition of coagulation abnormalities, underscoring the need for comprehensive initial assessments in cases of unexplained hematuria. The patient's management at a specialized Hemophilia Center involved inhibitor eradication therapy and management of acute bleeding episodes, resulting in significant clinical improvement. The conclusions drawn from this case emphasize the importance of considering rare conditions like AHA in the differential diagnosis of hematuria and the necessity for a broad diagnostic approach. It advocates for heightened awareness and early coagulation studies in unexplained cases of hematuria to prevent delayed diagnoses and improve patient outcomes. This case contributes to the understanding of AHA's clinical variability and the critical nature of early and comprehensive diagnostic approaches in hematuria evaluation.

Key Genes of the Immune System and Predisposition to Acquired Hemophilia A: Evidence from a Spanish Cohort of 49 Patients Using Next-Generation Sequencing

Acquired hemophilia A (AHA) is a rare bleeding disorder caused by the presence of autoantibodies against factor VIII (FVIII). As with other autoimmune diseases, its etiology is complex and its genetic basis is unknown. The aim of this study was to identify the immunogenetic background that predisposes individuals to AHA. HLA and KIR gene clusters, as well as KLRK1, were sequenced using next-generation sequencing in 49 AHA patients. Associations between candidate genes involved in innate and adaptive immune responses and AHA were addressed by comparing the alleles, genotypes, haplotypes, and gene frequencies in the AHA cohort with those in the donors' samples or Spanish population cohort. Two genes of the HLA cluster, as well as rs1049174 in KLRK1, which tags the natural killer (NK) cytotoxic activity haplotype, were found to be linked to AHA. Specifically, A*03:01 (p = 0.024; odds ratio (OR) = 0.26[0.06-0.85]) and DRB1*13:03 (p = 6.8 × 103, OR = 7.56[1.64-51.40]), as well as rs1049174 (p = 0.012), were significantly associated with AHA. In addition, two AHA patients were found to carry one copy each of the low-frequency allele DQB1*03:09 (nallele = 2, 2.04%), which was completely absent in the donors. To the best of our knowledge, this is the first time that the involvement of these specific alleles in the predisposition to AHA has been proposed. Further molecular and functional studies will be needed to unravel their specific contributions. We believe our findings expand the current knowledge on the genetic factors involved in susceptibility to AHA, which will contribute to improving the diagnosis and prognosis of AHA patients.

[Rapid diagnosis of acquired hemophilia A with ClotPro viscoelastometry analyser]

Acquired hemophilia A is a rare condition with the capability of bringing about life-threatening bleeding in the perioperative period, posing a significant challenge for the caregiver anesthetist to identify the underlying cause. However, a quick diagnosis might be supported by viscoelastometry by raising the suspicion of severe and isolated deficiency of the intrinsic coagulation pathway, requiring a prompt consultation with a hematology center. Special laboratory tests of hemostasis are helpful in the differential diagnosis of the detected coagulation disorder. Nevertheless, bypassing agents have gained a crucial role in the treatment of major perioperative blood losses by bypassing Factor VIII inactivated by autoantibodies and thus, initiating coagulation. Early goal-directed supplementation of depleted coagulation factors must also be kept in the focus of the therapy. Orv Hetil. 2023; 164(40): 1600-1604.

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 haemophilia A: A 15-year population-based review of incidence rate, patient demographics and treatment outcomes

INTRODUCTION

Acquired haemophilia A (AHA) is a rare bleeding disorder characterized by autoantibodies against coagulation factor VIII (FVIII). Estimates of AHA incidence are largely based on registry data, which may be prone to referral bias. Population-based studies can enhance our understanding of the epidemiology, presentation and outcomes of AHA.

METHODS

We conducted a retrospective, population-based cohort study of all AHA diagnosed and treated in Manitoba, Canada over a 15-year period. Using records from the sole provincial reference laboratory, we identified all patients with FVIII inhibitors who did not have congenital haemophilia.  Using a piloted case report form, patient data was ascertained from hospital and bleeding disorder clinic records.

RESULTS

From 2006 to 2021, we identified 34 patients with AHA, corresponding to a population-based incidence rate of AHA of 1.78 cases per million per year. The median age at presentation was 76 years and most cases were idiopathic (79%). Almost all patients (97%) presented with bleeding, of which 58% were considered major bleeds and required haemostatic agents in 67%. Longstanding unexplained bleeding symptoms were commonly reported, suggesting delayed diagnosis. Immunosuppressive therapy (IST) was administered in 88% of patients. Remission was achieved in 79% of patients; median time to remission was 2.1 months. There were two deaths due to bleeding. No deaths due to IST were reported.

CONCLUSION

The population-based incidence of AHA in Manitoba is 1.78 cases/million/year. Bleeding is common and can be life-threatening. AHA outcomes are encouraging with the use of haemostatic agents and IST. Serious treatment-associated morbidity and mortality is uncommon.

Clot Waveform Analysis for Monitoring Hemostasis

Clot waveform analysis (CWA) is a recently developed global coagulation assessment, based on the continuous observation of changes in light transmittance, absorbance, or light scattering that occurs as fibrin formed in a plasma sample during routine clotting tests such as activated partial thromboplastin time (aPTT) and prothrombin time (PT). CWA can utilize qualitative waveform patterns as well as sensitive quantitative parameters and can be used as a simple method to assess global hemostasis, and can be applied to various challenging clinical situations. Although not all coagulation analyzers currently in use are able to provide CWA, the number of analyzers available to do so is increasing, as the usefulness of this process has become more widely recognized. CWA can be based on the coagulation mechanism of aPTT, an intrinsic trigger, and this has been reported in many studies, including diagnosis and treatment of patients with hemophilia, disseminated intravascular coagulation, and monitoring of anticoagulants and thrombosis. CWA using trace amounts of tissue factors also has the potential to expand the applications of this technology. Recently, there have been reports of the combined evaluation of fibrinolytic dynamics. Among the existing global coagulation assays, CWA may prove to be the easiest to standardize in clinical practice. However, more extensive testing using standardized methods in various clinical settings is needed to determine the true role of CWA in the evaluation of hemostasis and thrombosis in the future.

Real-world safety and effectiveness of recombinant porcine sequence factor VIII in acquired haemophilia A: A non-interventional, post-authorization safety study

INTRODUCTION

Recombinant porcine factor VIII (rpFVIII, susoctocog alfa) is indicated for the treatment of bleeding episodes in adults with acquired haemophilia A (AHA).

AIM

To provide long-term real-world safety and effectiveness data for rpFVIII in the management of AHA bleeding episodes.

METHODS

US PASS (NCT02610127) was a multicentre, uncontrolled, open-label, post-marketing safety surveillance study conducted in adults with AHA. Data were collected retrospectively or prospectively for 180 days after rpFVIII treatment. The primary outcome was the incidence of treatment-related serious adverse events (SAEs). Secondary outcomes included haemostatic effectiveness of rpFVIII and rpFVIII utilization.

RESULTS

Fifty-three patients were enrolled from December 2015 to June 2019 (prospective, n = 30; retrospective, n = 23). Six patients experienced seven treatment-related SAEs (incidence 12.0%). The most common treatment-related SAE was FVIII inhibition (inhibiting antibodies to rpFVIII; incidence 8.0%, 95% CI: 2.2-19.2). Five patients reported seven thromboembolic events; one was an SAE and possibly related to rpFVIII. Of bleeding events treated with rpFVIII, 80.3% (57/71) of bleeds resolved with rpFVIII. The median (range) dose of rpFVIII per infusion was 50 (10-300) units/kg, with a median (range) of 6.0 (1-140) infusions and a median (range) time from bleed onset to bleed resolution of 14.0 (2.0-132.7) days.

CONCLUSION

In this real-world study of rpFVIII for AHA, no new safety signals were identified compared with previous clinical trial findings. Eighty percent of bleeds resolved with rpFVIII treatment.

Acquired haemophilia as a complicating factor in treatment of non-muscle invasive bladder cancer: A case report

BACKGROUND

Acquired haemophilia (AH) is a serious autoimmune haematological disease caused by the production of auto-antibodies against coagulation factor VIII. In some patients, AH is associated with a concomitant malignancy. In case of surgical intervention, AH poses a high risk of life-threatening bleeding.

CASE SUMMARY

A 60-year-old female patient with multiple recurrences of non-muscle invasive bladder cancer underwent transurethral tumour resection. A severe haematuria developed postoperatively warranting two endoscopic revisions; however, no clear source of bleeding was identified in the bladder. Subsequent haematological examination established a diagnosis of AH. Treatment with factor VIII inhibitor bypass activity and immunosuppressive therapy was initiated immediately. The patient responded well to the therapy and was discharged from the hospital 21 d after the primary surgery. At the 38-mo follow-up, both AH and bladder cancer remained in complete remission.

CONCLUSION

AH is a rare, life-threatening haematological disease. AH should be considered in patients with persistent severe haematuria or other bleeding symptoms, especially if combined with isolated activated partial thromboplastin time prolongation.