Lessons from a systematic literature review of the effectiveness of recombinant factor VIIa in acquired haemophilia

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.

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.

A case of acquired hemophilia A after pancreaticoduodenectomy for distal cholangiocarcinoma

Acquired hemophilia A (AHA) is a rare disease that results from factor VIII inhibitors causing abnormal coagulation, and certain cases may develop after highly invasive surgery. The present case study reports on a 68-year-old male patient who developed AHA after undergoing a subtotal stomach-preserving pancreatoduodenectomy for distal cholangiocarcinoma. The patient experienced complications after surgery, requiring reoperation on postoperative day (PD) 5 due to rupture of the Braun's enterostomy. On PD 6, angiography was performed after bleeding was detected in the jejunal limb, but hemostasis occurred spontaneously during the examination. Bleeding was observed again on PD 8 and direct surgical ligation was performed. On PD 14, bleeding recurred in the jejunal limb and angiography was performed to embolize the periphery of the second jejunal artery. During the procedure, the prothrombin time was normal, but only the activated partial thromboplastin time was prolonged. A close examination of the coagulation system revealed a decrease in factor VIII levels and the presence of factor VIII inhibitors, resulting in the diagnosis of AHA. Administration of steroids was initiated on PD 15 and, in addition to daily blood transfusions, activated prothrombin complex concentrate was administered to achieve hemostasis. The patient was discharged from the intensive care unit on PD 36 but later developed an intractable labial fistula due to suture failure at the gastrojejunostomy site. As the use of factor VIII inhibitors continued despite the administration of steroids, cyclophosphamide (CPA) pulse therapy was added at PD 58. However, CPA was ineffective and the administration of rituximab was initiated on PD 98. After 12 courses of rituximab, the patient tested negative for factor VIII inhibitors on PD 219. On PD 289, labial fistula closure was performed with continuous replacement of factor VIII and the patient was discharged on PD 342.

Current status and future prospects of activated recombinant coagulation factor VIIa, NovoSeven®, in the treatment of haemophilia and rare bleeding disorders

rFVIIa, a human recombinant activated coagulation factor VII, has been used worldwide for more than two decades for the treatment of bleeding episodes and prevention of bleeding in patients undergoing surgery/invasive procedures with congenital haemophilia A or B with inhibitors (CHwI A or B), acquired haemophilia (AH), congenital factor VII deficiency and Glanzmann thrombasthenia (GT), refractory to platelet transfusion. The approved dosage, administration and indication of rFVIIa in the US, Europe and Japan differ, depending on the needs of the patient population and regulatory practices. This review presents an overview of the current status and future prospects, including that from a Japanese perspective, of using rFVIIa in the treatment of approved indications. The efficacy and safety of rFVIIa in the approved indications has been demonstrated in several randomised and observational studies and data from registries. The overall incidence of thrombosis across all approved indications in a retrospective safety assessment of clinical trials and registries, prelicensure studies and postmarketing surveillance studies of rFVIIa use was 0.17%. Specifically, the risk of thrombotic events was 0.11% for CHwI, 1.77% for AH, 0.82% for congenital factor VII deficiency and 0.19% for GT. Emerging non-factor therapies such as emicizumab have changed the treatment landscape of haemophilia A, including preventing bleeding in patients with CHwI. However, rFVIIa will continue to play a significant role in the treatment of such patients, particularly during breakthrough bleeding or surgical procedures.

Acquired Hemophilia A Treated with Recombinant Porcine Factor VIII: Case Report and Literature Review on Its Efficacy

Acquired hemophilia A (AHA) is a bleeding disorder due to the presence of neutralizing autoantibodies named inhibitors in patients with a previously normal hemostasis. Recent international recommendations suggest the use of bypassing agents or substitutive therapy as the first-line treatment, usually preferring the former. The adequate hemostatic therapy needs an accurate balance between bleeding and thrombotic risks. We report a clinical case of acquired hemophilia A successfully treated with recombinant porcine factor VIII (Susoctocog alfa) as the first-line treatment. Despite the patient having a high-risk thrombotic score and a history of recent myocardial infarction, our experience showed the absence of thrombotic complications related to the use of Susoctocog alfa and a complete restoration of hemostatic parameters. Limited literature is present on the use of recombinant porcine factor VIII as a first-line treatment, and our report supports its use, especially when the thrombotic risk is high.

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

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

Acquired Haemophilia A: A Review of What We Know

Autoantibodies against plasma coagulation factors could be developed by some individuals inducing severe and sometimes fatal bleedings. This clinical entity is called acquired haemophilia. It should be suspected in subjects with acute abnormal bleedings, without personal or familiar history of congenital bleeding disorders with an unexplained prolonged aPTT. It is rare disease, although its incidence may be underestimated due to the low knowledge about it by many specialists, the frequent use of anticoagulant or antiplatelet therapies in the affected population that can mask the diagnosis and, sometimes, a so withering effect that avoid its confirmation. Mortality ranges between 9% and 33% depending on the series in the first 2 months after diagnosis. This mortality is attributed in up to 40% of the cases to infections in the context of immunosuppressive treatments used to eliminate the inhibitor. Factor VIII levels below 1% and high inhibitor titers are conditions of worse response rates. Advanced age, patient's ECOG, and underlying conditions are key prognostic factors for response to treatment and patient survival. To reduce morbidity and mortality in these patients, it is important to have clinical knowledge and access to guidelines to achieve an early diagnosis and to optimize the haemostatic and immunosuppressive treatment. This review aims to contribute to the dissemination of basic concepts on the epidemiology etiopathogenesis, diagnosis, treatment and management of these patients, as well as risk factors to get remission and the longest overall survival to allow individualized care. Especial awareness will be proposed in patients with some underlying conditions like cancer, autoimmune diseases, children, pregnancy or drugs.

Emergent Reversal of Antithrombotics and Treatment of Life-Threatening Bleeding from Coagulopathies: A Clinical Review

BACKGROUND

Reversal of antithrombotic agents and treatment of life-threatening bleeding episodes from coagulopathies can be a stressful scenario for clinicians, especially when the selection of treatment options should occur quickly. Understanding the options available for these agents requires emergency physicians to be familiar with the current data surrounding new therapies and dosing strategies for the treatment of bleeding from reversible and nonreversible antithrombotics and coagulopathic conditions.

OBJECTIVE

To provide quick resource guides for the reversal of major or life-threatening bleeding caused by antithrombotic agents or in the setting of coagulopathies.

METHODS

A literature search for articles published through September 2021 related to antithrombotic reversal and treatment of acute bleeding from coagulopathies was conducted using the PubMed clinical database. Selected articles were used to generate 5 guidance tables in this clinical review.

DISCUSSION

Four guidance tables for how to treat major or life-threatening bleeding from antithrombotic agents and 1 table for how to manage life-threatening bleeding for coagulopathies are presented as a quick reference tool for the emergency physician. Additional information on upcoming reversal agents and possible treatment options are provided herein.

CONCLUSIONS

In this clinical review, a series of 5 tables were created to provide quick and comprehensive guidance for the emergency physician when treating major or life-threatening bleeding caused by antithrombotic agents or coagulopathies. © 2022 Elsevier Inc.

Off-label use of emicizumab in persons with acquired haemophilia A and von Willebrand disease: A scoping review of the literature

INTRODUCTION

Since the approval of emicizumab, a bispecific, factor VIII-mimetic antibody, for use in persons with congenital haemophilia A in 2018, there have been increasing case reports and case series of off-label use of emicizumab in other bleeding disorders, including acquired haemophilia A (AHA) and von Willebrand disease (VWD).

AIM

We conducted a scoping review on the use of emicizumab in AHA and VWD, focusing on the clinical presentation and outcomes.

METHODS

We conducted a comprehensive search in PubMed, EMBASE and Scopus up to July 15, 2021. The following criteria were applied to the studies identified in the initial search: patients had a diagnosis of AHA or VWD; and the study reported on the clinical outcome of emicizumab use.

RESULTS

Seventeen studies were included in the final review for a total of 41 patients (33 AHA, eight type 3 VWD). The majority of AHA patients and all type 3 VWD patients were started on emicizumab for active/recurrent bleeds. The dosing regimen of emicizumab used varied significantly in AHA patients. All patients had a clinical response to emicizumab use. One AHA patient developed a stroke on emicizumab use in association with concomitant recombinant FVIIa use for surgery. Data on adverse events from emicizumab use were not specifically reported in 24.4% of patients (four AHA, six type 3 VWD).

CONCLUSION

Based on published case reports and case series, emicizumab appears to be an effective haemostatic therapy for AHA and VWD. Larger confirmatory clinical trials are needed to confirm these findings.

Unexplained hemorrhagic syndrome? Consider acquired hemophilia A or B

There is a dire need to develop an algorithm to improve the recognition of acquired hemophilia A and B (AHA and AHB) in clinical practice. Initial and intensive care unit (ICU) management of the disorder is particular and represents a challenge for the internist/hematologist and the ICU physician. A delay in the proper treatment of bleeding episodes can lead to a life-threatening event. Expert advice should be sought as soon as possible. Succesful resolution involves accurate diagnosis, bleeding control with hemostatic and immunotherapy, and eradication of the autoantibodies to improve overall survival. Current treatment guidelines are based on the literature in the form of cases and observational studies due to a lack of randomized controlled trials. AH can be triggered by many pathologies, presenting as a paraneoplastic syndrome in case of malignancies or as surgical associated acquired hemophilia (SAHA). We have reviewed the literature from 2015 to 2021 regarding the new case reports to further assess if there is an improvement in the clinical approach.

In vitro characterization of CT-001-a short-acting factor VIIa with enhanced prohemostatic activity

BACKGROUND

Traumatic injury and the associated acute bleeding are leading causes of death in people aged 1 to 44 years. Acute bleeding in pathological and surgical settings also represents a significant burden to the society. Yet there are no approved hemostatic drugs currently available. While clinically proven as an effective pro-coagulant, activated factor VII (FVIIa) use in acute bleeding has been hampered by unwanted thromboembolic events. Enhancing the ability of FVIIa to quickly stop a bleed and clear rapidly from circulation may yield an ideal molecule suitable for use in patients with acute bleeding.

OBJECTIVES

To address this need and the current liability of FVIIa, we produced a novel FVIIa molecule (CT-001) with enhanced potency and shortened plasma residence time by cell line engineering and FVIIa protein engineering for superior efficacy for acute bleeding and safety.

METHODS

To address safety, CT-001, a FVIIa protein with 4 desialylated N-glycans was generated to promote active recognition and clearance via the asialoglycoprotein receptor. To enhance potency, the gamma-carboxylated domain was modified with P10Q and K32E, which enhanced membrane binding.

RESULTS

Together, these changes significantly enhanced potency and clearance while retaining the ability to interact with the key hemostatic checkpoint proteins antithrombin and tissue factor pathway inhibitor.

CONCLUSIONS

These results demonstrate that a FVIIa molecule engineered to combine supra-physiological activity and shorter duration of action has the potential to overcome the current limitations of recombinant FVIIa to be a safe and effective approach to the treatment of acute bleeding.

Transplacental hemophilia A and prophylactic treatment with intravenous immunoglobulin and recombinant factor VIIa in the newborn period: a case report

Acquired hemophilia due to inhibitor antibodies to factor VIII (FVIII) is a very rare entity in neonatal period. Maternal IgG antibodies may cross the placenta and can cause life-threatening hemorrhages in newborns. Here, we represent a newborn who diagnosed as a transplacental acquired hemophilia A. A very high titer of inhibitor level (320 Nijmegen-Bethesda unit) was detected in plasma due to transplasental transfer in this case. According to the best of our knowledge the baby had the highest inhibitor level in neonatal period in the literature. Bleeding complications including intracranial hemorrhage secondary to this condition were reported before. Therefore, to prevent possible life complications, prophylactic recombinant FVIIa was administered in the presenting case and any bleeding event was not observed during follow-up. In conclusion, using prophylactic recombinant FVIIa in newborns is a safe choice for transplacental acquired hemophilia A.

Emicizumab for the treatment of acquired hemophilia A

Acquired hemophilia A (AHA) is a severe bleeding disorder caused by inhibiting autoantibodies to coagulation factor VIII (FVIII). For hemostatic treatment, bypassing agents and human or porcine FVIII are currently standard of care. Emicizumab is a bispecific, FVIII-mimetic therapeutic antibody that reduced the annualized bleeding rates in congenital hemophiliacs. Here, we report on 6 male and 6 female patients with AHA treated with emicizumab (all data medians and interquartile range), age 74 (64-80) years, initial FVIII <1%; inhibitor titer 22.3 Bethesda units (BU)/mL (range, 3-2000). Eight patients had severe bleeding. Emicizumab was started, 3 mg/kg subcutaneously, weekly for 2 to 3 doses, followed by 1.5 mg/kg every 3 weeks to keep the lowest effective FVIII levels. For FVIII monitoring, chromogenic assays with human and bovine reagents were used. All patients received immunosuppression with steroids and/or rituximab. After the first dose of emicizumab, activated partial thromboplastin time normalized in 1 to 3 days, FVIII (human reagents) exceeded 10% after 11 (7.5-12) days. Hemostatic efficacy was obtained and bypassing therapy stopped after 1.5 (1-4) days. FVIII (bovine reagents) exceeded 50%, indicating complete remission after 115 (67-185) days, and emicizumab was stopped after 31 (15-79) days. A median of 5 injections (range, 3-9) were given. No patient died of bleeding or thromboembolism, and no breakthrough bleeding was observed after the first dose of emicizumab. In conclusion, emicizumab seems to be an effective hemostatic therapy for AHA, with the advantages of subcutaneous therapy, good hemostatic efficacy, early discharge, and reduction of immunosuppression and adverse events.

Bleeding and response to hemostatic therapy in acquired hemophilia A: results from the GTH-AH 01/2010 study

Acquired hemophilia A (AHA) is due to autoantibodies against coagulation factor VIII (FVIII) and most often presents with unexpected bleeding. In contrast to congenital hemophilia, the patient's residual FVIII activity does not seem to correlate with the risk of bleeding as suggested from previous studies. Risk factors for bleeding have not been described. We used data from the prospective GTH-AH 01/2010 study to assess the risk of bleeding and the efficacy of hemostatic therapy. FVIII activity was measured at baseline and weekly thereafter. Bleeding events were assessed by treating physicians. A total of 289 bleeds were recorded in 102 patients. There were 141 new bleeds observed starting after day 1 in 59% of the patients, with a mean rate of 0.13 bleed per patient-week in weeks 1 to 12, or 0.27 bleed per patient-week before achieving partial remission. Weekly measured FVIII activity was significantly associated with the bleeding rate, but only achieving FVIII activity ≥50% abolished the risk of bleeding. A good World Health Organization performance status assessed at baseline (score 0 vs higher) was associated with a lower bleeding rate. Hemostatic treatment was reportedly effective in 96% of bleeds. Thus, the risk of new bleeds after a first diagnosis of AHA remains high until partial remission is achieved, and weekly measured FVIII activity may aid in assessing the individual risk of bleeding. These results will help to define future strategies for prophylaxis of bleeding in AHA.

Acquired hemophilia in a 7-year-old girl successfully treated with recombinant FVIIA and steroids: A case report

Acquired hemophilia should be evaluated in pediatric patients with bleeding and isolated prolonged aPTT. Immunosuppressive treatment should be initiated even in minor bleedings. Bypassing agents like rFVIIa can be used in children with success.

International recommendations on the diagnosis and treatment of acquired hemophilia A

Acquired hemophilia A (AHA), a rare bleeding disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII), occurs in both men and women without a previous history of bleeding. Patients typically present with an isolated prolonged activated partial thromboplastin time due to FVIII deficiency. Neutralizing antibodies (inhibitors) are detected using the Nijmegen-modified Bethesda assay. Approximately 10% of patients do not present with bleeding and, therefore, a prolonged activated partial thromboplastin time should never be ignored prior to invasive procedures. Control of acute bleeding and prevention of injuries that may provoke bleeding are top priorities in patients with AHA. We recommend treatment with bypassing agents, including recombinant activated factor VII, activated prothrombin complex concentrate, or recombinant porcine FVIII in bleeding patients. Autoantibody eradication can be achieved with immunosuppressive therapy, including corticosteroids, cyclophosphamide and rituximab, or combinations thereof. The median time to remission is 5 weeks, with considerable interindividual variation. FVIII activity at presentation, inhibitor titer and autoantibody isotype are prognostic markers for remission and survival. Comparative clinical studies to support treatment recommendations for AHA do not exist; therefore, we provide practical consensus guidance based on recent registry findings and the authors' clinical experience in treating patients with AHA.

Advances in managing rare acquired bleeding disorders

INTRODUCTION

Rare acquired bleeding disorders include a wide spectrum of coagulopathies characterized by spontaneous or post-trauma and post-surgery hemorrhages in patients without a previous personal or family history of bleeding.

AREAS COVERED

This review, based on a Medline/PubMed search during the last 20 years, will focus mainly on rare acquired bleeding disorders caused by autoantibodies against coagulation factors, including autoantibodies against factor VIII (acquired hemophilia A), von Willebrand factor (acquired von Willebrand syndrome) and other coagulation factors (factors V, X, XI, and XIII). The pathogenic, laboratory, and clinical features of these rare hemorrhagic conditions will be discussed, with particular attention to their management.

EXPERT OPINION

The treatment of rare acquired bleeding disorders includes the control of bleeding and the elimination of the autoantibody and of the underlying disease, when present. As the bleeding clinical phenotype is often severe, the management of affected patients is particularly challenging. Thus, while an early diagnosis of the acquired coagulopathy is essential to start the most appropriate treatment and to improve patients' outcomes, the support of specialized centers is equally important to provide a correct management of such complicated cases.

Recent advances in use of fresh frozen plasma, cryoprecipitate, immunoglobulins, and clotting factors for transfusion support in patients with hematologic disease

Hematologic diseases include a broad range of acquired and congenital disorders, many of which affect plasma proteins that control hemostasis and immune responses. Therapeutic interventions for these disorders include transfusion of plasma, cryoprecipitate, immunoglobulins, or convalescent plasma-containing therapeutic antibodies from patients recovering from infectious diseases, as well as concentrated pro- or anticoagulant factors. This review will focus on recent advances in the uses of plasma and its derivatives for patients with acquired and congenital hematologic disorders.

Inhibitor eradication and bleeding management of acquired hemophilia A: a single center experience in China

Objectives: Acquired hemophilia A (AHA) is a rare disease resulting from autoantibodies against coagulation factor VIII that leads to spontaneous bleeding. This study reports the clinical characteristics and treatment outcomes of a relatively sizable cohort of patients with AHA. Methods: We retrospectively analyzed the characteristics and outcomes of 42 patients with AHA diagnosed in our center from January 2014 through December 2018. Results: The FVIII activity (FVIII: C) was significantly suppressed (median 1.5%; interquartile range [IQR]: 0.9-3.5) by FVIII inhibitor (median 8 BU/mL; IQR: 4.0-16.0). Bypassing agents, PCC or FVIIa, were used in 14 patients for bleeding control without any adverse reaction; and most patients (90.5%, 38/42) were placed on immunosuppressive regimen, corticosteroid alone or in combination with cyclophosphamide. Patients treated with corticosteroids alone had a lower median inhibitor titer (8 BU/mL) than those treated with combination corticosteroids of cyclophosphamide (16 BU/mL) (p < 0.001). 97.4% (37/38) patients achieved complete remission (CR) after immunosuppression therapy, and the median time to CR in patients treated with corticosteroids alone was shorter than those with combination corticosteroids of cyclophosphamide (median 40 days; IQR: 31-65 vs. 51 days; IQR: 38-83, p = 0.301). 10 (26.3%) patients relapsed thereafter and were placed on combined corticosteroid and cyclophosphamide treatment, which yielded second remission in 8 patients (80%). Two patients died, one from uncontrolled post-surgical retroperitoneal hemorrhage and one from sepsis complicating corticosteroid therapy. Conclusion: The corticosteroid achieves a satisfactory outcome, particularly with low inhibitors titers; and combination of cyclophosphamide will facilitate remission in sever patients with high titers of inhibitors.

Overshoot of FVIII activity in patients with acquired hemophilia A who achieve complete remission

Acquired hemophilia A (AHA) is a rare, life-threatening bleeding disorder caused by autoantibodies against coagulation factor VIII (FVIII). Immunosuppressive therapy for AHA aims to arrest bleeding by eliminating FVIII inhibitors. Factor VIII activity overshoot after complete remission (CR) has been reported anecdotally, but details remain unclear. We retrospectively analyzed data from 17 patients with AHA who achieved CR under immunosuppressive therapy between 2009 and 2019 at Gunma University Hospital. FVIII activity overshoot was defined as ≥ 150%. All 17 patients had low FVIII activity (median 2.1%; range < 1.0-8.9%) due to FVIII inhibition (median 14.7 BU/mL; range 2.0-234.0) and all achieved CR within a median of 39 (range 19-173) days. Overshoot occurred in 11 (64.7%) patients and maximal FVIII activity reached > 200% in six of them. The median duration from CR to overshoot was 13 (range 0-154) days. The FVIII overshoot was transient (72.7%) or persistent (27.3%). Venous thromboembolism developed as a complication of overshoot in one patient due to iliac vein compression by a massive hematoma. Overshoot of FVIII activity after CR occurs more frequently than previously expected in patients with AHA.

Cross-reacting inhibitors against recombinant porcine factor VIII in acquired hemophilia A: Data from the GTH-AH 01/2010 Study

BACKGROUND

Recombinant porcine factor VIII (rpFVIII, OBI-1, susoctocog alfa) is used for the treatment of acute bleeds in patients with acquired hemophilia A (AHA). Inhibitors in AHA can sometimes cross-react with rpFVIII.

OBJECTIVES

To assess the frequency, strength, and determinants of cross-reactivity.

PATIENTS/METHODS

Baseline samples from 70 patients of the prospective, observational cohort study GTH-AH 01/2010 were assessed for anti-human FVIII and anti-rpFVIII inhibitors using modified Nijmegen-Bethesda assays, as well as anti-human FVIII domain reactivity using enzyme-linked immunoassay (ELISA).

RESULTS

Anti-human FVIII inhibitors were present in all samples ranging between 0.7 and 3891 Bethesda Units (BU)/mL. Inhibitors from 31 of 70 patients (44%) partially inhibited rpFVIII with anti-rpFVIII titers ranging between 0.5 and 471 BU/mL. Anti-rpFVIII titers were ≤5 BU in most patients. Patients with cross-reacting inhibitors, as compared to patients without, had significantly higher anti-human FVIII titers (27.8 versus 5.4 BU/mL) and lower baseline FVIII activity (<1 versus 2.6 IU/dL). The ratio between anti-rpFVIII to anti-human titers was highest for inhibitors involving the C1 domain. Cross-reactivity was very rare, if inhibitors reacted only with the C2 domain of FVIII (6%). An anti-human FVIII titer of >100 BU/mL predicted cross-reactivity with 97% likelihood, whereas an anti-human FVIII titer of <3.8 BU/mL predicted absent cross-reactivity with 90% likelihood.

CONCLUSION

Cross-reacting inhibitors should be considered when choosing a treatment for bleeding patients with AHA. Cross-reactivity is frequent in patients with anti-human FVIII titers of >100 BU/mL.

Acquired Hemophilia A: A Case Report

Hemophilia A, also known as factor VIII deficiency, is a rare disorder caused by an insufficient level of factor VIII, an essential clotting protein. Hemophilia A can be inherited or acquired. Inherited hemophilia A is caused by a mutation to the factor VIII gene on the X chromosome, which is commonly passed down from parents to children. However, in about one-third of cases, the cause is a spontaneous mutation in that gene. Acquired hemophilia A is due to an autoantibody to factor VIII, which is termed an inhibitor. This rare disorder can cause life-threatening bleeding complications. Management relies on a rapid and accurate diagnosis, control of bleeding episodes, and eradication of the inhibitor by immunosuppression therapy. Most treatment strategies are centered around anecdotal reports or small case series. This case report summarizes the successful treatment of a patient with acquired hemophilia A and major bleeding following a surgical procedure, with the use of desmopressin, recombinant factor VIIa, repeated doses of recombinant factor VIII, rituximab, and prednisone.

Hemostatic Agents in Critically Ill Patients

How to cite this article: Das SK, Reddy MM, Ray S. Hemostatic Agents in Critically Ill Patients. Indian J Crit Care Med 2019;23(Suppl 3):S226–S229.

Blood, blood components, plasma, and plasma products

This review of 2018 publications identifies side effects of blood, blood components, and plasma products. In addition, albumin, blood transfusion (erythrocytes, granulocytes, and platelets), blood substitutes (hemoglobin-based oxygen carriers), plasma products (alpha1-antitrypsin, C1 esterase inhibitor concentrate, cryoprecipitate, and fresh frozen plasma), plasma substitutes (etherified starches, and gelatin), globulins (intravenous immunoglobulin, subcutaneous immunoglobulin, and anti-D immunoglobulin), coagulation proteins (factor I, factor II, factor VIIa, factor VIII, factor IX, prothrombin complex concentrate, antithrombin III, and von Willebrand factor/factor VIII concentrates), erythropoietin and derivatives, thrombopoietin and receptor agonists, transmission of infectious agents through blood donation, and stem cells are reviewed. This chapter informs the reader about newly recognized and published data in the blood product domain.

Prevention and Management of Bleeding Episodes in Patients with Acquired Hemophilia A

Acquired hemophilia A (AHA) is a rare autoimmune disease caused by autoantibodies inhibiting the function of coagulation factor VIII. It is characterized by spontaneous bleeding in patients with no previous family or personal history of bleeding. Although several large registries have collected clinical data on AHA, limited information is available on the optimal management of AHA because controlled clinical trials are lacking. AHA can easily be diagnosed if the problem (prolonged activated partial thromboplastin time in a bleeding patient) is recognized. After the effects of anticoagulants are excluded, low factor VIII activity and the detection of circulating inhibitors confirms the diagnosis. However, lack of familiarity with this rare condition may delay diagnosis and adequate therapy. Treatment of AHA is based on measures for prompt hemostatic control to stop (and prevent) bleeding, immunosuppression to eradicate the autoantibodies, and supportive care for the adverse effects of that treatment and patients' often complex comorbidities. This article gives a comprehensive overview of the current knowledge about the pathophysiology, diagnosis, and treatment of AHA.