Reduced-intensity, risk factor-stratified immunosuppression for acquired hemophilia A: single-center observational study

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.

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.

Inhibitor eradication and treatment for acquired hemophilia A

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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.

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.

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 haemophilia A in southern Switzerland from 2013 to 2019: a case series

AIMS OF THE STUDY: Acquired haemophilia A is a rare disease with an annual incidence of 1.48 per million. Based on clinical observations, we suspect a higher incidence in southern Switzerland, and aimed at providing local epidemiological data, and clinical information regarding diagnosis, treatment and outcome in our region. METHODS: All adult patients with acquired haemophilia A treated between 2013 and 2019 in our facility were included in the present retrospective analysis. RESULTS: We treated 11 patients with acquired haemophilia A between 2013 and 2019, resulting in an annual incidence of 4.5 per million (95% confidence interval [CI] 0–9.0). Median delay from first symptoms to diagnosis was 4.5 days, and the median age at diagnosis was 79 years (range 23–87). Possible causative conditions were: pregnancy (n = 1), polyarteritis nodosa (n = 1), myelodysplastic syndrome (n = 1), chronic human immunodeficiency virus (HIV) (n = 1), and HIV postexposure prophylaxis (n = 1). In five patients no underlying or associated condition was identified. Median activated partial thromboplastin time (aPTT)) at baseline was 79 seconds (65–117; ref. value <38 sec), and FVIII:C 2.15% (<1–3.75%). A FVIII:C <1% was present in 4/10 patients. Median FVIII-inhibitor titre was 10.3 BU/ml (2.4–75.0 BU/ml). All patients had bleeding symptoms, 5/10 patients had major bleedings, and 7/10 patients were treated with bypassing agents. All patients received corticosteroids; 7/10 patients received immunosuppressive combination therapy. FVIII levels of ≥50% were achieved after a median of 40 days (8–62). One patient had a severe immunosuppressive therapy-related infection. An 87-years-old woman died for reasons not related to acquired haemophilia A or immunosuppressive therapy. CONCLUSIONS: Acquired haemophilia A is a rare disease, but manageable despite the advanced patient age and comorbidities. Its incidence in Southern Switzerland is higher than previously suspected.

A low-dose rituximab regimen for first-line treatment of acquired haemophilia A

A low-dose rituximab regimen for first-line treatment of acquired haemophilia A.

INTRODUCTION

Acquired haemophilia A (AHA) is a rare disease caused by the development of autoantibodies against FVIII. Diagnosis involves confirmation of FVIII deficiency and the presence of an inhibitor via the Bethesda assay. Severe bleeding is often managed with bypassing agents such as recombinant factor VII. This is then followed by eradication of the inhibitor with immunosuppression which typically includes a corticosteroid backbone.

AIM

Review the current management and outcomes of AHA in Queensland, Australia. Determine the incidence, demographics and clinical characteristics of AHA patients.

METHODS

Retrospective case series of AHA diagnosed between May 2014 and August 2018. Data were derived from the Australian Bleeding Disorders Registry and state-wide pathology database. Data collection proforma was completed by the treating haematologist and reviewed/compiled centrally.

RESULTS

24 patients were identified (incidence 1 in 1.27 million). The median age was 76.5 years. Median follow-up was 20 months. Index bleed was atraumatic and skin/soft tissue in the majority of patients. Recombinant FVIIa was the most commonly used haemostatic therapy and effective in 85% of patients. Immunosuppression and steroid usage were uniform. Upfront second agent was used in 75% of patients and was most commonly rituximab. 87.5% of patients achieved a complete remission in a median time of 48 days. Low-dose rituximab was frequently used and equally as efficacious as standard dose.

CONCLUSION

Immunosuppression with combination therapy, notably rituximab, appears to be non-inferior and has a favourable side effect profile.

Clinical characteristics and prognostic factors of acquired haemophilia A in Korea

INTRODUCTION

Acquired haemophilia A (AHA) treatment involves the haemostatic treatment for acute haemorrhage and immunosuppressive therapy (IST) to eradicate FVIII inhibitory antibodies.

AIM

We assessed the clinical features of AHA and analysed treatment outcomes in Korea. We further identified prognostic factors affecting treatment outcomes.

METHODS

Medical records of 55 patients with AHA from 18 institutions were reviewed retrospectively. Logistic and Cox regression analyses were performed to elucidate clinical factors affecting the achievement of complete remission (CR). The primary endpoint was time to CR after IST, and secondary endpoints were time to haemostasis, the achievement of CR, and overall survival (OS).

RESULTS

Among the 55 patients, 50 (91%) had bleeding symptoms. Bleeding was severe in 74% of patients. Thirty-six (72%) patients received haemostatic therapy. Of the 42 patients who received IST, 23 (52%) received steroid alone, with a 52% response rate, and 10 (25%) received a combination of steroid and cyclophosphamide, with an 83% response rate. Five (16%) patients relapsed after a median duration of 220 days. There were eight deaths. In the Cox regression analysis, the FVIII inhibitor titre ≥ 20 BU/mL was the only significant prognostic factor affecting time to CR and haemostasis. No significant difference was observed in OS based on the inhibitor titre.

CONCLUSION

The present study demonstrated the demographic data of AHA in Korea and showed that FVIII inhibitory antibody titre was a predictor of time to achieve CR after IST.

Acquired haemophilia A: successful treatment of a patient using upfront immunosuppressive therapy and haemostatic agents

Acquired haemophilia A (AHA) is a rare and possibly fatal autoimmune disorder that is challenging to treat. Although a majority of cases are idiopathic, AHA can also be associated with an underlying malignancy, autoimmune disorder, pregnancy, infection or certain medications. The diagnosis and treatment of AHA require a specialist with both clinical and laboratory expertise. The goal of treatment is aimed at achieving haemostasis as well as eradicating factor inhibitors. We present a patient with AHA and life-threatening haemorrhage who was successfully treated with a combination of haemostatic agents and a triple-drug immunosuppressive regimen. In reviewing recent studies and published guidelines, we advocate that a newer agent, emicizumab, can potentially be incorporated into the treatment protocol for AHA given its promising performance in the realm of congenital haemophilia.

Should emicizumab be used in patients with acquired hemophilia A?

Emicizumab is currently approved to prevent bleeding in patients with congenital hemophilia A with or without neutralizing antibodies (inhibitors) against factor VIII (FVIII). Here, we present a case-based discussion of its potential use in acquired hemophilia A (AHA), a severe bleeding disorder caused by autoantibodies against FVIII. State-of-the-art management is based on bypassing agents (recombinant factor VIIa, activated prothrombin complex concentrate) and recombinant porcine FVIII; immunosuppressive therapy (corticosteroids, rituximab, cyclophosphamide) is used to suppress autoantibody formation. Case reports and one series suggest that emicizumab can reduce the risk of bleeding and the requirement for hemostatic therapy until remission of AHA is achieved. Further, it may allow to postpone the start of immunosuppressive therapy or to use less intense regimens. However, the risk-benefit assessment of emicizumab in AHA is difficult because demographic and clinical characteristics are different compared with congenital hemophilia. Prospective clinical trials are needed before the use of emicizumab can be recommended in AHA.