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Keywords:

  • acquired haemophilia;
  • activated partial thromboplastin time;
  • FVIII;
  • immune tolerance induction;
  • immunoadsorption;
  • immunomodulation;
  • MBMP protocol

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

Summary.  Acquired haemophilia (AH), an autoimmune disorder with clinical features ranging from harmless haematomas to life-threatening bleedings, still has a mortality rate of up to 25%. Owing to its low frequency (1–4 × 106), standardized treatment protocols for its variable manifestations are not available. In case of prominent severe bleedings, the treatment should aim at rapid elimination of the antibody to protect patients from bleedings and on reinduction of long-term immune tolerance. Clinical data, short- and long-term treatment results of 67 patients diagnosed by our centre are presented. Patients were treated depending on their bleeding severity either by an immunosuppressive treatment alone, or in case of life-threatening bleedings, by a combined protocol (modified Bonn–Malmö protocol, MBMP) consisting of antibody depletion through immunoadsorption, intravenous immunoglobulin treatment, immunosuppression and high-dose factor VIII (FVIII) substitution. Mild bleedings occurred in two patients who were treated successfully alone by immunosuppression. Complete remission (CR) was achieved in 90% of the patients treated with MBMP (60). Of the six patients (10%) who achieved a partial remission (PR), four suffered from cancer. Mortality under MBMP was not seen. In contrast, five patients, in whom diagnosis of AH was delayed, experienced fatal outcome during surgical interventions before initiation of MBMP treatment. Prognosis in AH depends mainly on its prompt diagnosis. Treatment procedures should be adapted to bleeding severity and inhibitor titres. Under these conditions, AH is a potentially curable autoimmune disorder with an excellent prognosis.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

Acquired haemophilia (AH) is a bleeding disorder caused by autoantibodies (inhibitors) against coagulation factors [1,2]. The clinical picture ranges from harmless haematomas to severe life-threatening bleedings. Owing to the low frequency of AH treatment, protocols for the variable manifestations need to be developed. Conventional treatments focus on long-term immunosuppression to eradicate the inhibitor, most commonly through the application of corticosteroids alone or in combination with cyclophosphamide [3]. Recently, B-cell depletion via the CD20 antibody was proposed as new treatment option especially for severe cases [4] or as a first-line therapy when cytotoxic drugs are contraindicated [5]. In general the response to this treatment is unpredictable and may last several months, which exposes the patient to a high risk of bleedings over a long period of time [6].

As AH occurs mainly in the second half of life, the prognosis in these patients depends especially on the side effects of long-term immunosuppression. Despite improvements in the intensive care management, the prognosis of elderly patients has remained poor [7,8]. A meta-analysis of 249 cases [9] showed severe side effects after 6 weeks of treatment in 53% of the patients with a mortality rate of 15%. Recently, a 2-year national surveillance study of 172 patients with AH was undertaken by the United Kingdom Haemophilia Centre Doctors’ Organisation in order to identify and characterize the different features and treatment results in this patient group. Bleeding was the cause of death in 9% of the cohort and remained a high-risk factor until the inhibitor had been eradicated. Nevertheless, a relapse rate of 20% was observed in patients who initially achieved a complete remission (CR) [10].

Considering these findings, the overall goal in the treatment of severe AH should be the fast and safe inhibitor elimination to control first the bleeding episodes and second to reinduce the immunotolerance with the aim of finally curing the patient from the inhibitor.

In the present study, the clinical and laboratory data, treatment, outcome and long-term follow-ups of 67 patients with AH diagnosed in our centre are analysed and discussed. The treatment decision was adjusted to the severity of bleeding. Patients with life-threatening bleedings underwent the modified Bonn–Malmö protocol (MBMP) consisting of: (i) immunoadsorptive inhibitor removal; (ii) immuno-suppression; (3) high-dose factor VIII (FVIII) and (iv) intravenous (i.v.) immunoglobulin (Ig) substitution. All patients were monitored in a long-term follow-up of between 8 months and 10 years to document the treatment success.

Patients and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

Patients

Between 1998 and 2008, a series of 67 AH cases were diagnosed in our centre. We reported already earlier about 35 of these patients [11]. The following represents an update of the meanwhile 67 treated AH cases. Sixty-five patients were characterized by high-titre inhibitors to FVIII (>5 Bethesda Units, BU) [12] and the occurrence of at least one acute bleeding episode (drop of haemoglobin to <8.0 mg dL−1). The novel treatment protocol was approved by the Ethics Committee of the Medical Faculty at the University of Bonn. All patients or their responsible relatives gave their informed consent in writing.

The inhibitor analysis was performed with the Bethesda assay modified by Nijmegen [13]. Differential diagnosis with respect to the lupus erythematosus-associated inhibitor was established with the dilute Russell viper venom test, lupus-activated partial thromboplastin time, the plasma dilution test and determinations of the factors II, V, VII, IX, X and XI. The FVIII levels were determined by two methods: the one-stage clotting assay and the chromogenic FVIII assay.

Recombinant factor VIIa (rFVIIa) was substituted in 27 patients after diagnosis to achieve an immediate reduction in bleeding diathesis during the patient’s transfer to our hospital. CR was defined as normal FVIII activity (70–140%) without factor substitution and undetectable inhibitor titre levels during a minimum follow-up period of 12 months.

Partial remission (PR) was defined as attaining FVIII recoveries by up to 30% and/or a reduction of the inhibitor titre to less than 5 BU without further bleeding events.

A total of 60 patients with AH were treated:

  • 1
     Large-volume immunoadsorption (IA; 2.5–3 ×  total plasma volume on days 1–5)
  • 2
     i.v. Ig substitution [0.3 g kg−1 body weight (BW) day−1, on days 5–7]
  • 3
     Immunosuppressive therapy with cyclophosphamide (1–2 mg kg−1 BW day−1) and prednisolone (1 mg kg−1 BW day−1) from day 1 until remission (dose reduction)
  • 4
     Administration of FVIII [100 U kg−1 BW, and in exceptional cases (BMI > 40), up to 200 U kg−1 BW] every 6 h. Optional dose reduction on the basis of clinical signs and the level of recovery achieved (50–80% FVIII residual activity after 4–6 h) throughout the treatment cycle.

The treatment cycles (from day 1 to day 7) were repeated, depending on the clinical response and coagulation factor activity. IA was accomplished by apheresis of sheep-derived polyvalent anti-human Ig bound to sepharose CL 4B (Amersham Pharmacia, Biotech AB, Uppsala, Sweden), using a dual-column system (Ig Miltenyi Biotec GmbH, Plasmaselect Division, Bergisch Gladbach, Germany). Blood was drawn from an antecubital vein on one arm at a rate of up to 70 mL min−1, and returned after processing via an antecubital vein on the other arm. Alternatively, in the case of inadequate antecubital vein access, a biluminal central venous catheter was placed after premedication with rFVIIa at a concentration of 90–120 μg kg−1 BW. Plasma was continuously separated at a flow rate of up to 80 mL min−1 using either of the two apheresis systems (Cobe Spectra; Cobe Labs Inc., Lakewood, CO, USA or Autopheresis-C® Therapeutic Plasma Systems; Baxter Healthcare Corp., Round Lake, IL, USA), with acid-citrate-dextrose (ACD-A; Baxter Healthcare Corp.) as an anticoagulant diluted 1:30 or 1:40, respectively, in the two systems. The separated plasma was passed through the columns. The adsorptive capacity of the columns was 1.25 g for all IgG subclasses [11,14].

The target of processing was 2.5 times the plasma volume, and apheresis was continued for 5 days in each treatment cycle. After apheresis, either plasma-derived or recombinant human FVIII was administered, typically 100 IU kg−1 every 6 h, or in one exceptional case (BMI > 40), up to 200 IU kg−1 every 6 h. The FVIII dosage could be optionally reduced in cases of satisfactory clinical response and 4–6 h recoveries of 50–80% throughout the treatment cycle. The magnitude of such dose reductions was equal to 20% of the coagulation factor dose administered on the preceding day.

Data analysis

All statistical analyses were performed using the Statistical Package for Social Sciences SPSS, version 16.0 (SPSS, Inc., Chicago, IL, USA). Parametric statistics, the Pearson rank correlation (rs) test were used.

The primary study endpoints were the time at which (i) activity of the inhibitor was first undetectable, (ii) the factor substitution could be discontinued and (iii) the termination of the MBMP treatment without the requirement for further apheresis. Kaplan–Meier analysis was performed to evaluate the time at which these endpoints were reached. The median time to reach these endpoints was calculated on the basis of the associated 95% confidence intervals (95% CI).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

Patients characteristics

A total of 67 patients (17 males, 50 females) of AH with high-titre inhibitor levels (>5 BU) were diagnosed in our hospital. Sixty-five patients exhibited life-threatening bleeding (maximum haemoglobin on admission: 8.0 mg dL−1) requiring blood transfusions and intensive care monitoring. In two patients, the clinical bleeding was not life threatening (haemoglobin > 10 mg dL−1). The mean age of the patients was 62 ± 16.8 years (mean ± SD).

Laboratory diagnosis

The mean FVIII level at initial diagnosis and at the beginning of the MBMP was <2.4% (normal: 70–140%). The mean inhibitor titre was 457 BU mL−1± 1042.

The mean activated partial thromboplastin time (APTT) on admission was 57.27 s ± 20.86 (normal range: 22–30 s).

FVIII inhibitor titres, but not FVIII concentrations correlated with the APTT prolongation (rs = 0.300, < 0.05)

Bleeding type and associated disorders

The types of bleeding observed included muscle bleeding (n = 67) associated with compartment syndrome (= 6), gastrointestinal bleeding (= 1), retroperitoneal bleeding (= 16), retropharyngeal bleeding, which required artificial respiration (= 5), and haematuria (= 3).

Underlying diseases were detected in 17 patients. In six women, the inhibitor was diagnosed peripartially (i.e. within 3 months of childbirth). Six patients suffered from other autoimmune diseases (mixed connective tissue disease: n = 4, psoriasis: n = 4, polymyalgia rheumatica: n = 1, Sjögren syndrome: n = 1) and in four patients the inhibitor occurred as paraneoplastic syndrome (lung cancer: = 1, paraproteinaemia n = 1, lymphoma: = 1, breast cancer: = 1).

Immunoadsorption

A total of 1099 IA procedures (apheresis) were carried out with an average of 19 apheresis sessions (median: 16, range: 8–62) per patient. The extracorporeal treatment was well tolerated. Mild side effects, such as hypotension, hypaesthesia owing to citrate anticoagulation (citric reactions) and allergic reactions occurred in less than 1% of all apheresis sessions that did not require an interruption of treatment. A median plasma volume of 5560 mL (range: 3700–9500 mL) was treated.

Factor substitution

The mean amount of FVIII that was substituted during the MBMP to achieve CR in patients was 0.196 × 106 IU ± 0.5 × 106 IU. Patients with PR received an average of 0.39 × 106 IU ± 0.26 × 106 IU FVIII concentrate. A median amount of rFVIIa of about 0.66 × 103 (range: 0–8.24 × 103 kIU) was administered. The time course of the development of the FVIII activity and the administered dosages of FVIII for a representative patient are shown in Fig. 1.

image

Figure 1.  The laboratory coagulation parameters during modified Bonn–Malmö protocol. On the left y-axis (inline image ), inhibitor titre (BU mL−1) is shown over the course of apheresis procedures in a representative patient. On the right y-axis (inline image), the change in measured factor VIII (FVIII) activity is shown over the course of apheresis procedures. The dose of administered FVIII IU ×1000 is marked as (inline image ). The treatment phases are marked by grey arrows.

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Clinical outcome, treatment efficiency and side effects

MBMP  Out of 67 patients, 60 patients underwent MBMP. In 58 patients MBMP was completed. Due to catheter occlusion treatment was interrupted in two patients in the third and twelfth treatment cycles, respectively (Fig. 2).

image

Figure 2.  Outcome and long-term follow-up of modified Bonn–Malmö protocol patients.

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Fifty-four patients who completed MBMP achieved CR. PR was achieved in four patients. In this subgroup, malignant disorders with a poor prognosis were diagnosed during the course of the treatment. The improvement of blood clotting owing to our protocol permitted patients to undergo diagnostic steps for tumour staging, including pleurodesis, bone marrow aspiration, lymph node biopsy or mediastinoscopy without bleeding events. Once apheresis started, bleeding was controlled in all 58 patients.

Figure 3 indicates the time points at which undetectable inhibitor levels were achieved (Fig. 3a), coagulation factor concentrates could be discontinued (Fig. 3b) and extracorporeal treatment was discontinued (Fig. 3c). The mean number of apheresis days required to reach these endpoints was 4.4 days (95% CI 2.9–5.8 days), 17 days (95% CI 14.1–20 d) and 19 days (95% CI 16.2–22.3 days), respectively.

image

Figure 3.  Treatment endpoints were rapidly reached in the modified Bonn–Malmö protocol group. Kaplan–Meier plots of: (a) mean time to reduce inhibitors to undetectable levels, CI (confidence interval); (b) mean time of substitution; and (c) mean time of treatment. The abscissa shows time in apheresis days. Numbers above the Kaplan–Meier curves represent patients completing the protocol within the corresponding time period. Vertical excursions of the curves signify the occurrence of events.

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The FVIII inhibitor titre correlated with the treatment days (rs = 0.514, P < 0.01).

Conventional treatment  Two patients with moderate clinical bleedings were treated conventionally. The first patient was a young female patient who developed the inhibitor postpartum (FVIII inhibitor titre: 5 BU mL−1, FVIII activity 4%) with mild bleeding symptoms (muscles haematoma). She was treated successfully with steroids over a period of 3 months. The second patient was a 79-year-old man with haemorrhage gastritis and mild muscle haematomas (FVIII inhibitor titre 74 BU mL−1, FVIII activity 4%). He suffered from a severe chronic obstructive lung disease and severe chronic heart failure and was treated successfully with a combination of steroids (1 mg kg−1 BW) and cyclophosphamide (2 mg kg−1 BW) over a period of 9 months. Nevertheless, he experienced a progressive renal failure during immunosuppressive treatment resulting in an increase of serum creatinine from 1.7 mg dL−1 before to 2.9 mg dL−1. Treatment had to be interrupted several times owing to respiratory and urinary infections.

Fatalities  Five patients died as direct consequence of AH before MBMP could be started. One patient experienced an ischemic stroke under rFVII treatment during the transport to our centre. Four patients experienced a delayed inhibitor diagnosis and had fatal outcomes owing to surgical interventions performed by the referring hospitals (compartment syndrome n = 3, diagnostic laparatomy n = 1).

Long-term follow-up and outcome

Once apheresis was started, bleeding stopped immediately in all 58 patients and no subsequent bleedings were encountered. During a long-term follow-up (median 62 months, range: 12–126 months), there was no evidence of any inhibitor relapse in 55 patients. Three patients experienced a period of FVIII decline to 10–50% without any bleeding events during a respiratory infection. These patients had received a conventional therapy prior to our protocol treatment. In two patients, relapses were managed by apheresis for 5–6 days, as well as immunosuppressive therapy, the third patient was treated only with steroids for 4 weeks. These interventions succeeded in restoring normal FVIII levels, and the clinical condition of the patients remained stable. None of the patients died as a direct consequence of the bleeding events.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

This clinical study represents the largest worldwide treatment documentation of a cohort of AH patients diagnosed by a single centre. This cohort has special features as mainly severely affected patients are referred to our hospital. In 97% (65/67), the clinical symptomatology was dominated by life-threatening bleeding. But we demonstrate here that the majority of these patients could be treated successfully by MBMP.

The higher prevalence of the female gender (50/67) in our cohort is common in the development of autoimmune diseases and female predominance in autoimmunity has been examined by other authors [15]. Whereas in half of the patients AH is reported to be of idiopathic nature, in the other half an occurrence of another autoimmune disease is discussed as a trigger. In the majority of our patients (50), an underlying aetiology was not detected. Possibly, the percentage of idiopathic AH is higher than so far assumed. However, our patients had an average of 62 years and old age also may promote the development of AH.

The main challenge in the treatment of AH appears to be its delayed diagnosis. Beside the bleedings, the prolongation of APTT is the most important screening test that may indicate the occurrence of an inhibitor. In our collective, there was a significant correlation between inhibitor titre and APTT prolongation but not with FVIII concentrations. This discrepancy might base on the complex type II kinetic of the inhibitor resulting in a rapid and non-linear inactivation of FVIII. As APPT is the main parameter in supervising the anticoagulatory effect of heparin, its relevance in the differential diagnosis of bleeding disorders is often underestimated. Four of our patients died during surgery (haematoma revision). Therefore, surgical interventions in AH in the presence of the inhibitor and in the absence of an adequate coagulatory treatment carry a high risk. The benefit of rFVIIa in controlling acute bleedings is generally accepted [16] nevertheless its prothrombogenic effect induced in one of our patients a fatal ischemic stroke. Therefore, a local thrombogenic effect of rFVIIa in the presence of cardiovascular risk factors needs to be considered, especially in elderly patients [17,18]. Summer et al. [19] reports that about 6% of AH patients treated with rFVIIa suffer from thrombotic events.

In 58 patients, MBMP was completed. Treatment interruptions were rare (3%, 2/60) and not related to the treatment itself, but owing to bad vascular conditions that did not allow the continuation of the MBMP. In the cases in which the therapy was completed, MBMP induced a CR in 93% (54/58) of the patients. In the remaining 7% (4/58), PR was achieved. These patients differed from the rest of the group as they suffered not only from AH, but also from malignancies. Nevertheless, in this group MBMP allowed invasive diagnostic steps for tumour staging without bleeding complications. The presentation of a FVIII molecule by tumour cells might explain the mechanism of this ‘subtype of AH’ therefore not being curable via an immunmodulatory treatment. In this collective, a tumour-specific therapy might be successful in the long-term inhibitor eradication.

CR was confirmed in a long-term follow-up of these patients over a mean period of 62 months. The eradication of the inhibitor by MBMP proceeds generally in three phases (Fig. 1). The initial phase I is characterized by a rapid inhibitor decline owing to IA resulting in an increase of FVIII recovery. Phase II requires, although the inhibitor titre is at low level, high doses of FVIII substitution until a sufficient FVIII concentration is achieved. This results in a further mobilization of autoantibodies from the tissue and is the so-called steady-state phase. Finally, in phase II a brisk FVIII increase marks the definitive inhibitor elimination, thereby allowing the cessation of factor substitution. Despite this clinical experience little is known about the immunological mechanism that might be involved in this treatment success.

IA allows the presentation of high doses of intact FVIII to the autoreactive memory B cell in an environment with more or less no inhibitor. This might be the most important therapeutical step in MBMP. Brackmann et al. [12] described the immunmodulatory effect of the long-term application of high-dose FVIII in congenital haemophilia as an effective strategy for inhibitor eradication inducing a long-lasting immune tolerance. Hausl et al. [20] reported a T-cell-independent irreversible inhibition of memory B cell response by high doses of FVIII, resulting in a downregulation of anti-FVIII antibodies in haemophilic mice. How far these mechanisms are transferable to AH has not yet been answered.

Although i.v. Ig have been shown to be of little benefit in inhibitor eradication, the rationale of their implementation in MBMP is a more immunmodulatory approach supporting the reconstruction of an idiotypic network after intense Ig depletion [21]. As reported earlier [11], the treatment costs for MBMP are high but they occur only once. The main share of the treatment cost is related to the FVIII substitution (average dose 0.196 × 106 IU) and potentially required rFVII. In addition, $1000 US for each IA needs to be calculated [11]. In conventional treatments, recurring costs accumulate because of additional bleeding events and longer hospital stays [11]. However, the MBMP costs can possibly not be borne by all haemophilia centres in the world.

In conclusion, AH is in contrast to other autoimmune diseases a curable disorder. The choice of treatment should be adapted to severity of bleeding and the inhibitor titre. In patients with life-threatening bleeding, MBMP is a realistic option, whereas alternative immunosuppressive treatments may be chosen in mild AH.

Disclosures

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References

J. Oldenburg has acted as a paid speaker and consultant, received a reimbursement for attending a symposium, received a fee for organising education, as well as received funds for research and a member of staff. The other authors stated that they had no interests which might be perceived as posing a conflict or bias.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Disclosures
  8. References