Acquired hemophilia A in the United Kingdom: a 2-year national surveillance study by the United Kingdom Haemophilia Centre Doctors' Organisation

Atypical acquired hemophilia linked with primary biliary cholangitis: a unique case presentation

Acquired hemophilia A is an uncommon disease often presented with bleeding episodes causing a significant mortality risk. The main responsible for the threatening hemorrhagic disorder is the Factor VIII autoantibody's development. Acquired inhibitors' presence is frequently idiopathic, but it can be associated with malignancy, pregnancy, drugs and autoimmune diseases. In this report, we present the first case of acquired hemophilia A associated with primary biliary cholangitis. A 48-year-old man, presented with diffuse oral bleeding after a tooth extraction. Hemostasis testing revealed a markedly prolonged activated partial thromboplastin time. The search for an anti-factor VIII inhibitor returned positive. The etiological investigation concluded primary biliary cholangitis, and the patient was treated with bypassing agent, immunosuppressive therapy, and ursodeoxycholic acid.

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

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.To present final analysis results of AGEHA, including data on IST-ineligible patients (Cohort 2) and on long-term prophylaxis with emicizumab.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.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.These results suggest that emicizumab prophylaxis has a favorable benefit-risk profile in PwAHA regardless of eligibility for IST.

Acquired Hemophilia Associated with Rheumatoid Arthritis: A Case Report and Review of the Literature

A 63-year-old woman with rheumatoid arthritis and Hashimoto's thyroiditis was admitted to the emergency room, because of left leg pain associated with spontaneous subcutaneous hematomas, for 15 days. Their symptoms also occurred after the discontinuation of aspirin, which the patient had taken for a previous case of ocular papillitis. Laboratory tests showed anemia, a normal platelet count, but a prolonged activated partial thromboplastin time (aPTT) ratio; a computerized tomography scan of the left lower limb detected a recent hematoma in the left lateral rectus muscle, and subcutaneous soft tissue edema also involving the knee, without vascular involvement. Coagulation tests were performed showing normal levels of Lupus Anticoagulant, very low-factor FVIII activity (2.2%), normal FIX, FXI, and FXII activity, and the detection of FVIII inhibitors by a Bethesda assay (7.6 U). A diagnosis of acquired hemophilia A (AHA) was made, and hemostatic and immunosuppressive treatment was immediately started (activated prothrombin complex concentrates and methylprednisolone). Malignancies and infections were excluded. An autoantibodies panel confirmed the positivity to rheumatoid factor and anti-cyclic citrullinated peptide antibodies. In treatment, the patient did not present any new bruises, with aPTT normalizing, FVIII increasing, and inhibitors reducing until disappearance. A close follow-up continued every 1-2 week after discharge, with hemostatic treatment discontinuation and methylprednisolone decalage. Underlying autoimmune conditions induced this rare, autoimmune and life-threating disorder.

Real-World Treatment Patterns and Long-Term Clinical Outcomes in Thai Patients With Acquired Haemophilia A

INTRODUCTION

Data regarding long-term clinical outcomes in Asian patients with acquired haemophilia A (AHA) was limited.

AIM

This study aimed to evaluate the effectiveness of current treatments and their outcomes in a real-world setting among Thai patients with AHA.

METHODS

This was a retrospective cohort study conducted at a university-based hospital. Patients' characteristics, treatment patterns and disease outcomes were collected. Univariate and multivariate Gray's competing risk analyses were used to examine the factors related to the time to disease response.

RESULTS

From 2009 to 2022, 69 AHA patients with a median age of 68 years (range 36-97) were enrolled. The majority of cases were characterised by the absence of an underlying aetiology (82.6%) and presented as major bleeding (71.0%). As first-line treatment, 79.7% were treated with steroid monotherapy, and 13.0% received a combination of steroid and rituximab. Thirty-one patients (44.9%) received at least one dose of haemostatic agents. After a median time to follow-up of 24.9 months (interquartile range 1.6-78.5), 41 patients (59.4%) attained first disease remission. Factor VIII below 1 IU/dL and the combination of steroid and rituximab were associated with time to disease remission, with subdistribution hazard ratio of 0.3 (95% confidence interval [CI], 0.1-0.7) and 5.2 (95% CI, 2.0-13.4), respectively. The most common complication in this cohort was infection (40.6%).

CONCLUSION

The combination of steroid and rituximab demonstrated efficacy in the management of AHA. In addition, infectious complications were a significant concern when treating AHA patients.

Lipopolysaccharide-binding protein functions as factor VIII inhibitor in bullous pemphigoid associated with acquired hemophilia A

Bullous pemphigoid (BP) represents an autoimmune blistering disorder that may coexist with acquired hemophilia A (AHA), a rare autoimmune condition arising from the formation of circulating autoantibodies directed against factor VIII (FVIII). The underlying pathomechanisms of BP-AHA remain elusive. This study conducted a retrospective analysis of data from 196 BP patients admitted to our hospital. We have collected serum samples from a recently admitted BP-AHA patient and healthy controls to isolate, screen and identify the potential FVIII inhibitors. The expression and function of lipopolysaccharide-binding protein (LBP) in BP-AHA were further validated by a series of biochemical experiments. The retrospective analysis showed that the activated partial thromboplastin time (APTT) values of seven patients exceeded 33.8 s (normal value) in 196 BP patients. FVIII: C (%) and FVIII inhibitors in the plasma of partial prolonged-APTT patients were significantly altered compared with control group or non-prolonged-APTT group. LBP was identified as a potential inhibitory protein of FVIII. Consistently, a notable alteration in LBP expression was observed in the plasma of BP patients with prolonged-APTT. Moreover, the amount of LBP bound to FVIII in the BP-AHA patient was notably higher than that in control group, which was also markedly reversed after treatment. In vitro experiments finally confirmed that exogenous LBP directly bound to FVIII and significantly inhibited FVIII activity. In conclusion, the incidence of AHA in BP patients may be substantially underestimated, which needs more vigilance towards indicators such as APTT, LBP, and FVIII. LBP emerges as an inhibitory protein of FVIII, indicating the potential involvement in the progression of BP-AHA.

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.

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.

Prognostic factors for recurrence in acquired hemophilia A-results from a long-term observational study

Objectives

Acquired hemophilia A (AHA) is a rare autoimmune disease caused by autoantibodies against factor (F)VIII (FVIII), potentially leading to life-threatening bleeding. While predictors for remission have been analyzed, data on recurrence is lacking.

Methods

This study investigated predictors of AHA recurrence in 41 patients. Patients were divided into 2 groups: those with recurrence (n = 18) and those in stable long-term remission (n = 23) with at least 1 year of follow-up.

Results

All relapses occurred within 1 year of initial remission. The median follow-up period was 3.8 years (IQR, 1.8-6.4) for all included patients. Multivariate Cox regression analysis revealed that initial FVIII activity <1 IU/dL and failure to achieve initial complete remission (CR) were significant predictors of relapse. Kaplan-Meier curves showed significantly different relapse-free survival rates for patients with initial FVIII activity <1 IU/dL vs ≥1 IU/dL (χ2[1] = 5.950, P = .015), and for those achieving initial CR vs partial remission (χ2[1] = 6.570, P = .010).Other factors such as inhibitor titer, gender, age, World Health Organization scale, underlying disorder, controlled disorder, initial immunosuppressive therapy, immunosuppressive therapy escalation, and partial remission at day 21 showed no significant relation to recurrences. Overall survival did not differ significantly between relapsing and nonrelapsing patients (χ2[1] = .896, P = .344).

Conclusion

Initial FVIII <1 IU/dL and failure to achieve initial CR are identified as risk factors for recurrence in AHA. Patients with these characteristics should be closely monitored for at least 1 year after initial remission due to increased recurrence risk.

A Case Report of Rare Coagulation Factor Abnormalities (Factors VII, XI, and XII) in a Patient With Chronic Subdural Hematoma and Treatment With Middle Meningeal Artery Embolization

Acquired coagulopathy is uncommon. Cases of hemophilia A, which is characterized by reduced coagulation factor Ⅷ, have been reported but cases involving diminished factors VII, Ⅺ, or XII have not been reported. We report the case of a patient who presented with a chronic subdural hematoma (CSDH), which was challenging to treat due to underlying acquired coagulation abnormalities. Middle meningeal artery (MMA) embolization is a promising approach for managing refractory CSDH and has proved effective in this case. An 82-year-old man with no significant medical history and family history presented with a headache and discomfort in his right lower extremity. A left CSDH was detected. Subsequent tests revealed prolonged activated partial thromboplastin time and decreased activities of coagulation factors VII, Ⅺ, and XII. Emergency burr-hole irrigation was performed after administering recombinant coagulation factor VIIa. Two months later, the patient developed aphasia and recurrent hematoma. MMA embolization using N-butyl cyanoacrylate was performed to avoid recurrence, and burr-hole drainage reduced brain compression. The symptoms were relieved, and no recurrence was reported after discharge. This case description highlights a rare case of CSDH caused by the decreased activities of factors VII, XI, and XII. In addition, the efficacy of MMA embolization in patients with CSDH and limited coagulation disorder treatment options was demonstrated.

Spontaneous Subdural Hematomas as Initial Presentation of Acquired Coagulopathy: A Case Report

The evaluation of coagulopathies can be challenging due to the extensive variety of etiologies. This can be particularly complicated in patients with concomitant autoimmune disorders. In this case, a 64-year-old woman presented with intractable headaches and neck pain for two weeks. Her coagulation tests revealed an isolated prolongation of activated partial thromboplastin time (aPTT). This case highlights the diagnostic approach and summarizes management considerations in patients with similar presentations.

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.

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.

[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.

Large Cell Neuroendocrine Carcinoma With Acquired Hemophilia A Diagnosed by Endobronchial Biopsy: A Case Report

Primary lung cancer with acquired hemophilia A is rare. We report a case of large cell neuroendocrine carcinoma (LCNEC) with acquired hemophilia A diagnosed by endobronchial biopsy. A 75-year-old male was admitted to our hospital due to severe anemia and multiple organ failure. Hematomas, prolonged activated partial thromboplastin time, decreased activity of factor VIII, and the presence of serum factor VIII inhibitors led to the diagnosis of acquired hemophilia A. Administration of recombinant activated factor VIII and steroid treatment resolved the coagulation abnormalities. Simultaneously, a CT scan showed a lung mass and an endobronchial biopsy confirmed the diagnosis of LCNEC. Although acquired hemophilia A can cause severe bleeding symptoms, a lung cancer diagnosis by bronchoscopy was possible under appropriate treatment of acquired hemophilia A.

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.

First-line immunosuppressive therapies for acquired hemophilia A: A 25-year cohort experience and network meta-analysis

Acquired hemophilia A (AHA) presents a significant bleeding risk. Management involves bleeding control and immunosuppressive therapy (IST) to eliminate inhibitors. This study, encompassing a retrospective cohort of 76 newly diagnosed AHA patients (1997-2022), evaluated IST outcomes such as complete remission (CR), relapse, and mortality rates, alongside influencing factors. Supplementing these findings, a systematic review and network meta-analysis compared CR and relapse rates across ISTs, sourcing from Embase, Scopus, and ScienceDirect up to November 2023. In our cohort, demarcated by a 20 Bethesda-unit titer threshold, cyclophosphamide plus prednisolone (CP; n = 64) was the predominant initial IST. Lower inhibitor levels significantly correlated with higher CR rates (86.8 % vs 62.2 %; P = .014) and showed an odds ratio of 0.26 for CR (P = .021). Median relapse-free survival (RFS) extended to 37.13 months, significantly enhanced by CP (hazard ratio, 0.24; 95 % confidence interval, 0.10-0.60; P = .002). Our network meta-analysis, including 1476 CR and 636 relapse patients, indicated CP and rituximab-based ISTs significantly outperformed steroid monotherapy in terms of CR and lower relapse rates (risk differences of 0.15 and -0.13/-0.15, respectively; P < .05), without significant differences between CP and rituximab. Moreover, adding rituximab to the front-line treatment did not produce superior outcomes compared to the CP regimen alone, positioning CP as a viable first-line choice, particularly where rituximab is less accessible. The consideration of IST toxicity remains critical in treatment decisions.

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.

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.

Concurrent congenital hemophilia B and acquired hemophilia A: a unique case report

Congenital hemophilia B is a rare X-linked recessive bleeding disorder caused by factor IX deficiency. Acquired hemophilia A is a rare, acquired bleeding disorder that presents with new-onset bleeding, especially in older adults, due to the development of auto-antibodies against factor VIII (FVIII). This case report presents the medical management of a patient with congenital hemophilia B and acquired hemophilia A. We highlight the limitations of maintaining factor levels with factor replacement therapy alone, particularly in hemophilia patients who have developed factor inhibitors. In addition, we draw attention to the need for dose escalation, the cost, and the need for immune-tolerance induction therapy. This case illustrates that when the current diagnosis does not explain the full clinical picture and laboratory data are inadequate, it is important to continue to seek alternative diagnoses and cost-effective treatment.

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.

Diagnosis and Treatment of Autoimmune Acquired Coagulation Factor Deficiencies: An Evidence-Based Review of Japanese Practice

Among the acquired coagulation factor deficiencies, autoimmune coagulation factor deficiencies (AiCFD) are rare and result from autoantibody production against coagulation factors. In Japan, a nationwide survey on AiCFD has been conducted since 2009. Autoimmune factor XIII, factor VIII, von Willebrand factor, factor V, and factor X deficiencies (AiF13D, AiF8D, AiVWFD, AiF5D, and AiF10D, respectively) have been enacted as "designated intractable disease-282." The incidence of AiF8D, AiF13D, and AiF5D was 1.83, 0.044, and 0.038 per million people/year, respectively, whereas that of AiVWFD and AiF10D was not calculable owing to the small number of patients. AiF13D and AiF8D were often idiopathic, whereas AiVWFD was often associated with plasma cell neoplasms. Epistaxis was a characteristic symptom of AiVWFD, intramuscular bleeding was frequent in AiF13D and AiF8D, and subcutaneous bleeding (purpura) was frequent in AiF13D and AiF10D, although none were specific to any one disease. Differential diagnosis cannot be made based on bleeding symptoms alone; therefore, rapid and accurate testing is mandatory. Definitive diagnosis of AiCFD necessitates identifying the presence of coagulation factor "inhibitors" and/or "autoantibodies." Therefore, these tests should be performed upon unexplained severe acquired coagulation factor deficiencies. The mainstay of treatment for AiCFD was hemostatic therapy and autoantibody eradication therapy, which included the replacement of coagulation factors or "bypass" agents and administration of immunosuppressants. The rate of hemorrhagic death was high in AiF13D (13%), followed by AiF5D (7%) and Ai10D (5%); therefore, early diagnosis and optimal treatment are essential for AiCFDs. Given the unknown long-term prognosis, "intractable disease platform registries" have begun to accumulate in Japan.

A Rare Case of Hemophilia: Acquired Factor VIII Deficiency

Unlike hereditary hemophilia, acquired hemophilia is a rare life-threatening bleeding disorder that occurs in a person who has no personal or family history of bleeding episodes. It usually presents with new-onset subcutaneous/joint/muscle bleeding causing ecchymoses and hematomas, hematuria, GI bleeding, retroperitoneal bleeding, or rarely acute intracranial hemorrhage in elderly individuals. The diagnosis involves assessing prolonged activated partial thromboplastin time (aPTT) and conducting mixing studies after ruling out lupus anticoagulants and interfering substances such as heparins. Management consists of controlling hemostasis using recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrates (aPCC), along with eradicating autoantibodies against factor VIII from the body system using immunosuppressive therapies. Due to the risk of uncontrolled bleeding in individuals who were previously normal, delayed diagnoses and recurrences are not uncommon, potentially resulting in unfavorable outcomes.

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 Hemophilia: A Rare Complication of Pediatric Idiopathic Multicentric Castleman Disease

Acquired hemophilia is caused by acquired autoantibodies to 1 of the factors of the coagulation cascade, usually factor VIII or IX, and is an exceedingly rare phenomenon in children. The finding of an acquired factor VIII inhibitor in a pediatric patient with idiopathic multicentric Castleman disease has never been reported. Patients with acquired hemophilia can have life-threatening bleeds that are refractory to blood product support, requiring bypassing agents to manage bleeding symptoms. We present the novel finding of acquired hemophilia resulting from an autoantibody to factor VIII in a pediatric patient with idiopathic multicentric Castleman disease and discuss the optimal management of bleeding in a patient with acquired hemophilia.

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.

Successful management of massive postpartum haemorrhage in a woman with acquired haemophilia A

Postpartum haemorrhage (PPH) is an obstetric emergency and a leading cause of severe maternal morbidity and mortality. Timely and accurate diagnosis of the underlying cause of PPH is critical in achieving optimal care for the patient as any potential delays may result in severe morbidity and even mortality. We present a rare case of a patient presenting with PPH secondary to acquired haemophilia. This case highlights the importance of early diagnosis and multidisciplinary management in achieving optimal management of this complex condition.

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.

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.

Immunotherapy of acquired hemophilia A

Acquired hemophilia A (AHA) is an autoimmune disorder characterized by the formation of autoantibodies that neutralize the function of coagulation factor VIII. Immunosuppressive therapy (IST) with glucocorticoids, cyclophosphamide, rituximab, or combinations thereof is the standard of care to suppress autoantibody formation and induce remission of AHA. About 80% of patients achieve remission over the course of a few weeks to several months. However, patients with AHA are often elderly and frail and have adverse events from IST. Therefore, guidelines suggest an individualized approach using caution in elderly and frail patients. Prophylaxis with emicizumab may reduce the need for early and aggressive IST in the future.

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.

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.

Emicizumab prophylaxis in patients with acquired haemophilia A (GTH-AHA-EMI): an open-label, single-arm, multicentre, phase 2 study

BACKGROUND

Acquired haemophilia A is caused by neutralising autoantibodies against coagulation factor VIII, leading to severe bleeding. Standard treatment involves immunosuppressive therapy, which is associated with adverse events and mortality in the frail population of patients with acquired haemophilia A. This study investigated whether emicizumab, a factor VIIIa mimetic antibody, protects patients with acquired haemophilia A from bleeding and allows deferral of immunosuppression during the first 12 weeks after diagnosis.

METHODS

We report final results of an open-label, single-arm, phase 2 clinical trial. Adult patients with acquired haemophilia A from 16 haemophilia treatment centres in Germany and Austria were eligible if they had not previously received immunosuppression. Patients received emicizumab subcutaneously (6 and 3 mg/kg on days 1 and 2, 1·5 mg/kg weekly until week 12), but no immunosuppression. Follow-up was until week 24. The primary endpoint was the number of clinically relevant bleeds per patient-week until week 12. Emicizumab was considered effective if the mean bleeding rate was significantly below 0·15 bleeds per patient-week, the rate observed in a previous study of patients with acquired haemophilia A treated with bypassing agents and immunosuppression but no emicizumab. The study is registered with clinicaltrials.gov, NCT04188639 and is complete.

FINDINGS

Of 49 patients screened from March 25, 2021, to June 10, 2022, 47 were enrolled (23 women, 24 men). Median age was 76 years (IQR 66-80), 46 (98%) of 47 patients were White, median factor VIII activity was 1·4 IU/dL (0·3-5·6), and median inhibitor concentration was 11·4 Bethesda units per mL (3·9-42·7). Mean breakthrough bleeding rate was 0·04 bleeds per patient-week (upper 97·5% CI 0·06). 33 (70%) of 47 patients had no bleeding events, seven patients (15%) had one bleed, six patients (13%) had two bleeds, and one patient (2%) had three bleeds. Adverse events of grade 3 or worse included COVID-19 (n=2), acute kidney injury (n=2), and stroke (n=1). Four of 47 patients died, including two deaths related to bleeding, one from COVID-19, and one from cardiac arrest (none were judged as related to emicizumab).

INTERPRETATION

This study suggests that emicizumab prophylaxis prevents bleeding in patients with acquired haemophilia A and that immunosuppressive therapy can be deferred while patients are receiving this treatment. The low number of thromboembolic events, severe infections, and fatalities observed in this study are promising.

FUNDING

This study was supported by funding from Hoffman-La Roche.

[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.