Complications associated with the treatment of haemophiliacs with inhibitors

Safety and efficacy of prothrombin complex concentrates for the treatment of coagulopathy after cardiac surgery

OBJECTIVE

Coagulopathy is an important cause of bleeding after complex cardiac surgery. The conventional treatment for coagulopathy is transfusion, which is associated with adverse outcomes. We report our initial experience with the prothrombin complex concentrate FEIBA (factor VIII inhibitor bypassing activity) for the rescue treatment of coagulopathy and life-threatening bleeding after cardiac surgery.

METHODS

Twenty-five patients who underwent cardiac surgery with coagulopathy and life-threatening bleeding refractory to conventional treatment received FEIBA as rescue therapy at our institution. This cohort represents approximately 2% of patients undergoing cardiac surgery in our university-based practice during the study.

RESULTS

The patients were at high risk for postoperative coagulopathy with nearly all patients having at least 2 risk factors for this. Aortic root replacement (Bentall or valve-sparing procedure) and heart transplant with or without left ventricular assist device explant were the most common procedures. The mean FEIBA dose was 2154 units. The need for fresh frozen plasma and platelet transfusion decreased significantly after FEIBA administration (P = .0001 and P < .0001). The mean internationalized normalized ratio decreased from 1.58 to 1.13 (P < .0001). Clinical outcomes were excellent. No patient returned to the operating room for reexploration. There was no hospital mortality and all patients were discharged home. One patient who had a central line and transvenous pacemaker developed an upper extremity deep vein thrombosis.

CONCLUSIONS

Our initial experience with FEIBA administration for the rescue treatment of postoperative coagulopathy and life-threatening bleeding has been favorable. Further studies are indicated to confirm its efficacy and safety and determine specific clinical indications for its use in patients undergoing cardiac surgery.

Safety, pharmacokinetics and efficacy of factor VIIa formulated with PEGylated liposomes in haemophilia A patients with inhibitors to factor VIII--an open label, exploratory, cross-over, phase I/II study

  Recombinant activated factor VIIa (FVIIa) is a bypassing agent used to treat bleeding episodes in haemophilia patients with inhibitors to factor VIII (FVIII) and factor IX. The pharmacological effect of FVIIa is short-lived and therefore with the recommended dose of 90 μg kg(-1), a bleeding episode is treated with multiple injections. A long-acting form of FVIIa that can ensure adequate haemostasis with a single infusion, without increasing the thrombotic risk, would therefore be beneficial. PEGylated liposomes (PEGLip) have been shown to bind FVIIa and to improve haemostatic efficacy in preclinical experiments. In the present phase I/II clinical trial, we assessed the safety and efficacy of PEGLip-formulated FVIIa in severe haemophilia A patients (FVIII≤1%) with inhibitors to FVIII. Each patient received one prophylactic infusion of standard FVIIa and one prophylactic infusion of PEGLip-formulated FVIIa. The order of the infusions was randomized and the two infusions were separated by a ten-day washout period. Efficacy assessed by thromboelastography revealed that PEGLip-FVIIa induced significantly shorter clotting times and produced higher clot firmnesses than standard FVIIa. Thrombin generation assays showed that PEGLip-FVIIa induced faster thrombin generation and higher peak levels of thrombin than standard FVIIa. These effects lasted up to 5 h postinfusion. Measurements of D-dimer, prothrombin fragment 1+2 and fibrinogen showed no significant differences between the PEGLip-FVIIa and standard FVIIa treatments. PEGLip-FVIIa therefore showed improved haemostatic efficacy without increased risk of thrombosis and may be further developed for the treatment for bleeding episodes in haemophilia patients with inhibitors.

Systemic AL amyloidosis with acquired factor X deficiency: A study of perioperative bleeding risk and treatment outcomes in 60 patients

Systemic light-chain (AL) amyloidosis may be associated with acquired factor X (FX) deficiency and optimal management of this coagulopathy is unknown. We reviewed our experience with 60 patients with isolated FX deficiency (< or =50%) due to AL amyloidosis that underwent an invasive procedure between 1975 and 2007. They were classified as having severe (<10%; n = 6), moderate (10-25%; n = 15), or mild (26-50%; n = 39) FX deficiency. The patients underwent a total of 112 procedures, 19 (17%) of which were managed with periprocedural treatment with one or more hemostatic agents. There were complications in 14 (13%) procedures (bleeding = 12, thrombosis = 1, death = 1). Baseline FX level was not predictive of bleeding risk; the only association with postintervention bleeding was central venous catheter placement. However, bleeding complications were relatively infrequent, particularly in patients with mild or moderate FX deficiency undergoing nonvascular procedures. Activated recombinant factor VII might be considered in patients undergoing major surgical procedures, but further experience is needed. Optimal management of AL patients with FX deficiency undergoing invasive procedures remains to be determined.

Prophylaxis in 10 patients with severe haemophilia A and inhibitor: different approaches for different clinical situations

The effect of bypassing agents is not as predictable as replacement therapy with the deficient factor in inhibitor patients. Consequently, these patients have more levels of arthropathy than patients without inhibitors. Prophylaxis for inhibitor patients has gained attention over the last decade and some papers have reported that bypassing agents could work in the prevention of arthropathy. However, there is a lack data to support any specific agent or regimen or even to recommend their use in different clinical conditions. We report ten patients with haemophilia A and inhibitors treated prophylacticaly with bypassing agents (5 with FEIBA and 5 with NovoSeven). The variable conditioning the choice of one agent or the other was the intention to initiate of immune tolerance induction therapy (ITI) in the future. In 8/10 patients (4 in FEIBA group and 4 in rFVIIa group) there was a decrease of bleeding episodes while 9/10 maintained or increased their joint range of motion (ROM). In the rFVIIa prophylaxis group, prophylaxis can be considered primary since all of them had had less than one joint bleed before prophylaxis. Economic analysis showed that prophylaxis is an expensive treatment. In our experience both agents seem to be safe and effective in reducing the number of bleeds in patients with inhibitors. The anamnestic response provoked by FEIBA could be an issue while awaiting a decline in titres before ITI can be initiated and so rFVIIa may be the best option for prophylaxis in patients with inhibitors who have not yet begun ITI.

Optimising immune tolerance induction strategies in the management of haemophilia patients with inhibitors: a cost-minimisation analysis

BACKGROUND

The objective of this study was to model the economic impact of optimal dosing of immune tolerance induction (ITI) in haemophilia patients with inhibitors. Evidence based research suggests that, in the right patient population characterised by ITI risk status, the use of high-dose ITI regimen in 'poor risk' patients, and the low-dose regimen in 'good risk' patients, would be the cost effective strategy. The model also explored the impact of anamnestic response (AR), a phenomenon which worsens patients' ITI risks.

METHOD

A cost-minimisation technique was used to compare the cost of managing inhibitor patients whose bleeds were managed pre-ITI with an immunogenic bypassing agent, activated prothrombin complex concentrate (APCC), with patients previously on a non-immunogenic product, recombinant activated factor VII (rFVIIa). Patients were subsequently offered a low-dose or high-dose ITI regime depending on their ITI risk status. The study perspective was that of the United Kingdom NHS, hence, all resources used were based on UK costs.

RESULTS

The model estimated the mean cost of managing inhibitor patients from detection of titres through ITI to be 959,250.39 pound sterling and 770,834.17 pound sterling in the APCC and rFVIIa treatment options, respectively. Meanwhile, the costs per effectively tolerised patients were 1,505,279 pound sterling and 1,196,706 pound sterling for APCC and rFVIIa treated patients, respectively. Of the incremental cost in the APCC-treated patients in the model, 129,367 pound sterling (68%) represents additional ITI cost attributable to anamnestic response to earlier treatment with an immunogenic bypassing agent (APCC).

CONCLUSION

The study concludes that decreasing factor VIII usage during ITI, through the identification and management of 'good risk' ITI patients with low-dose protocol, while managing 'poor risk' patients with high-dose regimen, will significantly lower the cost of ITI. Furthermore, avoiding AR prior to ITI by using non-immunogenic bypassing agents to manage spontaneous bleeds also has the potential for significant cost savings.

Blood component therapy

Blood component transfusion is integral in the treatment of infants and children by pediatricians, surgeons, intensivists, and hematologists/oncologists. Technologic advances in blood collection, separation, anticoagulation, and preservation have resulted in component preparation of red blood cells, platelets, white blood cells, and plasma, which are superior to whole blood used in the past. Advances in donor selection, infectious disease testing, leukoreduction filters, and gamma irradiation have made products safer. Physicians prescribing blood components should have a basic understanding of indications (and contraindications) and be cognizant of methods of preparation, proper storage conditions, and requirements for modification of blood products to prevent potential adverse effects.

An overview of the history, clinical practice concerns, comparative studies and strategies to optimize therapy of bypassing agents

Despite significant advances in the treatment of haemophilia, including availability of recombinant coagulation factor replacement products and the use of prophylactic infusion regimens, the segment of haemophilic patients who develop inhibitory antibodies remain at higher risk for morbidity and mortality associated with recurrent or uncontrolled bleeding events. Bypassing agents represent the mainstay of treatment and prevention of bleeding. The most commonly used of the currently available therapeutic agents are a plasma-based therapy, factor eight inhibitor bypassing activity, vapour heated, and a recombinant therapy, NovoSeven (recombinant activated factor VIIa). A substantial body of literature exists to document efficacy and adverse event profiles for these two products. There is, however, a paucity of data arising from adequately powered prospective trials to determine optimal treatment and dosing in various clinical situations. Certain clinical circumstances, patient profiles, individual responses, or provider predilection may lead to preferential use of one of these products over the other; however, the continued presence of both agents in the therapeutic armamentarium remains critically important to this fragile population. The historical use, clinical practice concerns, published comparative studies and methods for optimization of these two bypassing agents are reviewed.

Health economic review of recombinant activated factor VII for treatment of bleeding episodes in hemophilia patients with inhibitors

Severe hemophilia with inhibitors is a rare disease with substantial clinical, humanistic and economic consequences. This review provides an overview of the role of recombinant activated factor VII (rFVIIa) versus plasma-derived bypassing agents for hemophilia with inhibitors and summarizes the 13 formal economic analyses (6 burden of illness and 7 comparative studies) that have been published in this indication. The findings suggest that the economic impact of rFVIIa has occurred primarily during hospitalization to manage major bleeding episodes and to allow for elective orthopedic surgeries that would not have been attempted prior to rFVIIa. Comparative analyses for on-demand treatment suggest that the total cost of treating a bleeding episode with rFVIIa may be lower than with plasma-based agents due to faster bleeding resolution, higher initial efficacy rates and avoidance of second and third lines of treatment.

Prophylactic treatment with activated prothrombin complex concentrate (FEIBA�) reduces the frequency of bleeding episodes in paediatric patients with haemophilia A and inhibitors

Orthopaedic complications are among the most disabling sequelae occurring in patients with haemophilia and inhibitors. Recurrent or refractory joint bleeds can lead to joint damage, limiting mobility and causing permanent disability. Activated prothrombin complex concentrates (aPCCs) are effective in controlling acute, intraoperative and postoperative bleeding in patients with haemophilia and inhibitors. The relatively long, dosing interval and safety profile distinguish aPCCs as a well-suited option for prophylaxis. Therefore, it is postulated that long-term routine aPCC administration will decrease the frequency of recurrent bleeds, prevent damage to normal joints, and slow the progression of existing joint disease in patients with inhibitors. To test this hypothesis, a retrospective chart audit was performed. In four treatment centres, five patients were identified who received aPCC [Factor Eight Inhibitor Bypassing Activity, Anti-Inhibitor Coagulant Complex (FEIBA); Baxter AG, Vienna, Austria] prophylactically for > or = 6 months to prevent or reduce further joint deterioration, reduce bleeding and prevent postsurgical bleeding. Median treatment duration was 15 months and included administration of >1300 doses of aPCC. Dosages ranged from 50 to 75 U kg(-1) three times per week in four patients; one patient received 100 U kg(-1) daily. Orthopaedic status was maintained in four patients and improved in one; the frequency of bleeding episodes was reduced in all patients. No adverse events or thrombotic complications were reported. This case series demonstrates that routine aPCC administration may be used safely and effectively to reduce the occurrence of bleeding episodes and to maintain or improve clinical joint status in some patients.

IgE-mediated anaphylactic reaction to purified and recombinant factor VIII in a patient with severe haemophilia A

We report a 51-year-old patient with severe haemophilia A developing a severe life-threatening anaphylactic reaction to recombinant factor VIII (rFVIII). Anaphylactic reactions are a rare but well-known side effect of FVIII products. The nature of these reactions could not be clarified as previous studies failed to demonstrate a specific IgE response. Here, we could prove a grade 3 anaphlyactic reaction as an IgE-mediated response to rFVIII for the first time by Western blotting.

Recombinant activated factor VII decreases bleeding without increasing arterial thrombosis in rabbits

PURPOSE

To compare the effects of recombinant activated factor VII (rFVIIa) and platelet-rich plasma (PRP) in an experimental model of bleeding and arterial thrombosis.

METHODS

The Folts model was used in 60 rabbits. After anesthesia, the carotid artery was exposed and a 75% stenosis was induced. A compression injury of the artery triggered a series of cyclic flow reductions (CFRs). After counting baseline CFRs, animals were assigned randomly to one of four groups (n = 15 in each): control, PRP, rFVIIa and placebo. Control animals received 10 mL.kg(-1) of saline while 10 mL.kg(-1) of a hydroxyethyl starch solution (200,000/6%/0.5) were infused in the three other groups. CFRs were measured again, followed by treatment with PRP, rFVIIa or placebo and by a final measurement of CFRs. At the end of each observation period, an ear immersion bleeding time (BT) was measured and a blood sample was drawn for the evaluation of hematological variables. Microvascular bleeding was evaluated at the end of the experiment in grams of blood shed from liver and spleen sections. Results are presented as median (range).

RESULTS

rFVIIa shortened the BT and decreased microvascular bleeding as compared with placebo [60 (35-100) sec vs 110 (50-140) sec, P = 0.0019 and 9 (4-24) g vs 17 (5-28) g, P = 0.002, respectively]. rFVIIa did not increase CFRs [3(0-9) vs |(0-5), P = 0.11].

CONCLUSION

rFVIIa led to a decrease in BT and microvascular bleeding but did not significantly affect arterial thrombosis in rabbits.

Recombinant factor VIIa: review of efficacy, dosing regimens and safety in patients with congenital and acquired factor VIII or IX inhibitors

Recombinant factor (rF)VIIa has been available to clinicians since 1996 and has an excellent safety record after almost three-quarters of a million doses have been administered. This paper will review the current clinical experience with rFVIIa dosing in acquired and congenital hemophilia with inhibitors and chronicle all spontaneous and clinical trial reports of thrombotic adverse events as of April 2003. Standard dosing of rFVIIa (90 micro g kg(-1)) allows binding of FVIIa to the surface of an activated platelet and can directly activate factor X in the absence of tissue factor. Experience with bolus dosing suggests that higher dosing (>200 micro g kg(-1)) may be more efficacious in treating hemophilia patients. Clinical trials are ongoing to validate this observation. Continuous infusion dosing may be efficacious for major surgery but high infusion rates (50 micro g kg(-1) h(-1)) might be needed. The relationship between dose of rFVIIa, amount of thrombin generated and measurable FVIIa level is still not known and perhaps newer testing which measures thrombin generation might be more advantageous. Relatively few thrombotic events have been associated with rFVIIa. Known factors predisposing to thrombosis were present in 20 of the 25 (80%) hemophilia patients who were reported spontaneously or who developed a thrombosis during a clinical trial. Additionally, thrombotic events have not increased despite a growing experience with higher dosing of rFVIIa.

Ablation of hemophilic FVIII inhibitors with FVIII priming, cyclophosphamide immune suppression, and rapid tapering of FVIII immune tolerance

The efficacy and toxicity of factor VIII (FVIII) priming, cyclophosphamide immune suppression, and rapid tapering of concurrent FVIII immune tolerance for subjects with hemophilic inhibitors were evaluated. Four subjects with hemophilic inhibitors were studied. Before treatment, inhibitors were present for a median of 8 months (mean 13 +/- 14.0 months). The median FVIII inhibitor titer was 16 BU/mL (mean 27.2 +/- 29.2 BU/mL). Following FVIII priming (80.0 +/- 70.2 U/kg), subjects received cyclophosphamide 1,418 +/- 636 mg/M2 i.v. q3 weeks for 4.4 +/- 1.7 courses. Subjects concurrently received a low (6 U/kg/day), moderate (30 U/kg/day), or high (100 U/kg/day) dose of FVIII followed by a rapid taper as the inhibitor titer decreased or resolved. During treatment, the inhibitor titer initially increased but then rapidly declined. Inhibitors resolved in 3.9 +/- 2.9 months. One inhibitor recurred at 2.8 years, but it was successfully re-treated. Effectiveness did not depend on the FVIII dose. Toxicity was minimal. Cyclophosphamide (1,400 mg/M2) administered after a priming dose of FVIII (80 U/kg) i.v. q3 weeks for 2-6 cycles with a rapid taper of concurrently administered daily FVIII as the inhibitor titer falls is an effective approach to hemophilic inhibitor ablation.

Efficacy of NovoSeven during surgery on a haemophiliac with previous history of inhibitors

Management of bleeding in haemophiliacs with a history of inhibitor remains problematic. With infusion of factor VIII (FVIII), development of an anamnestic response and possible appearance of high-titre inhibitor remains a valid concern. We report a case of a haemophiliac with a history of moderately high-titre FVIII inhibitor that had become undetectable. He had not received FVIII since 1997, when he became inhibitor negative. He had been managed during his bleeding episodes with prothrombin complex factor concentrates, which became less effective in controlling his bleeding. The patient had a history of recurrent, spontaneous shoulder joint dislocations with bleeding, pain and significant disability. Shoulder joint replacement surgery was suggested. Replacement therapy was discussed with the patient, who refused treatment with human FVIII because of his concern for possible anamnestic response and inhibitor rebound. Porcine FVIII was not acceptable due to his poor response when used once in the past, and his history of moderate allergic reaction. Therefore, recombinant factor VIIa (NovoSeven, Novo Nordisk, Princeton, NJ) was considered to be an acceptable option for the contemplated shoulder surgery. The patient underwent 2.5 h of surgery with NovoSeven infusion. The surgeons were impressed with the lack of bleeding in this traumatic surgery. Despite the continuously prolonged activated partial thromboplastin time and low FVIII levels, the patient maintained a remarkably dry surgical field. Effective haemostasis was achieved during and after this procedure. This case illustrates the usage of NovoSeven as an effective treatment modality in a haemophilia A patient with past history of inhibitor undergoing joint surgery.

Anti-inhibitor coagulant complex for the rescue therapy of acquired inhibitors to factor VIII: case report and review of the literature

A 62-year-old African-American man with a history of hypertension, asthma, and prostate cancer, but no prior history of haemophilia presented with gross haematuria following a motor vehicle accident. Coagulation studies revealed a prolonged partial thromboplastin time. Subsequent mixing study and factor analysis confirmed factor VIII (FVIII) deficiency. The patient subsequently developed a knee haemarthrosis associated with persistent haematuria and a profoundly elevated FVIII inhibitor titre. Fresh frozen plasma was initiated upon presentation. Once FVIII inhibitor was discovered, immunosuppressive agents were started. Concurrent treatment with acute bypass agents including porcine FVIII, and recombinant human factor VIIa (rFVIIa;NovoSeven), was also given. Ultimately, anti-inhibitor coagulant complex (Autoplex T) was administered, stabilizing the haematuria and haemarthrosis. There was no additional bleeding 6 months after the last dose of anti-inhibitor coagulant complex. This case is consistent with others in which anti-inhibitor coagulant complex therapy was used successfully to manage patients with serious acute bleeding problems who are found to have acquired inhibitors to factor VIII.

Safety of factor VIII inhibitor bypass activity (FEIBA): 10-year compilation of thrombotic adverse events

Published and unpublished spontaneously reported thrombotic adverse events (AEs) in factor VIII inhibitor bypass activity (FEIBA(R)) recipients were compiled for the most recent 10-year period during which FEIBA(R) units equivalent to 3.95 x 105 typical infusions were distributed worldwide. A total of 16 thrombotic AEs were documented over the 10-year period, corresponding to an incidence of 4.05 per 105 infusions (95% CI, 2.32-6.58 per 105 infusions). Disseminated intravascular coagulation (n=7) and myocardial infarction (n=5) were the most frequent thrombotic AEs. One fatality occurred in an 87-year-old metastatic cancer patient. In 13/16 (81%) patients known risk factors were present, most commonly FEIBA(R) overdose in 8/16 (50%), obesity in 3/16 (19%) and serum lipid abnormalities in 2/16 (12%). These findings indicate that thrombotic AEs in FEIBA(R) recipients are very rare. Recognition of risk factors and avoidance of FEIBA(R) overdosage may avert thrombotic AEs.

Thrombotic stroke associated with the use of porcine factor VIII in a patient with acquired haemophilia

Porcine factor VIII (pFVIII), which is used to control bleeding in patients with congenital or acquired haemophilia who have high-titre neutralizing antibodies to human FVIII, is not known to increase the risk of arterial or venous thrombosis. We have recently encountered a patient with acquired haemophilia who developed a thrombotic left middle cerebral artery distribution stroke while being treated with pFVIII. To our knowledge, this is the first such reported thrombotic event. We speculate that platelet activation induced by pFVIII may have contributed to thrombosis and suggest that pFVIII be used with caution in elderly patients with pre-existing cardiovascular risk factors.

Therapeutic choices for patients with hemophilia and high-titer inhibitors

Effective treatment of bleeding episodes in hemophilia with high titer inhibitors (HTI) remains a challenge, despite the fact that the therapeutic armamentarium has expanded considerably over the past few years. Treatment safety has improved with the availability of porcine factor VIII (FVIII) and bypassing products such as recombinant factor VIIa (rFVIIa), and plasma-derived activated Prothrombin Complex Concentrates (aPCCs) that are virally inactivated. The major drawbacks of rFVIIa and aPCCs are their unpredictable hemostatic effect, lack of laboratory assays to monitor efficacy and dosing frequency, and the risk of thrombosis. The proceedings of a one-day workshop of physicians who specialized in treating patients with hemophilia held in Vienna on May 13, 2000 have been summarized. In making a decision regarding the choice of product, physicians often consider the type of bleeding episode (life or limb threatening), age of the patient, volume of the reconstituted product, previous exposure to plasma derived products, cost, efficacy, and safety. For plasma naïve patients, to achieve rapid hemostasis a majority of the panelists used porcine FVIII (for patients who lack porcine inhibitory antibodies) or rFVIIa. For patients previously treated with plasma derived factors, in addition to the above concentrates, aPCCs were recommended. Although no data exists regarding safety and efficacy, switching products was routinely practiced either because of availability or cost. Furthermore, the panelists were uncertain about the efficacy of bypassing agents in the prevention of joint disease in inhibitor patients. The workshop participants felt that future research offers the best solution to resolve some of the dilemmas faced by clinicians and may help individualise treatment in a hemophilia patient with a high titer inhibitor.

The future of plasma-derived clotting factor concentrates

In developed countries, preferred treatments for both haemophilia A and B have moved toward recombinant clotting factor concentrates, while plasma-derived replacement therapies are still required by many patients. Great improvements have been made in producing relatively pathogen-free clotting factor replacements from pooled plasma. The fluidity and complexity of the worldwide plasma product market are discussed in the context of the 'yin and yang' of plasma therapeutics, showing how multiple issues can influence the safety and availability of clotting factor concentrates. Use of plasma-derived products will likely continue for the next decade for patients with inhibitors, patients with von Willebrand disease, those requiring bypassing agents, in immune tolerance induction, and for treatment of rare inherited deficiencies of procoagulant or anticoagulant proteins. Furthermore, in developing countries many of the most advanced therapies are not available for the majority of haemophilia patients, and thus plasma-derived replacement concentrates will continue to be used even for noninhibitor patients.