The evolution of comprehensive haemophilia care in the United States: perspectives from the frontline

The establishment of dedicated comprehensive treatment centres more than a half century ago transformed the management of haemophilia in the United States. Formerly, a disease associated with crippling disability and premature death, today, persons with haemophilia who are treated appropriately from infancy and do not develop inhibitors can expect a normal life expectancy and relatively few bleeding episodes. The evolution of the comprehensive haemophilia care, while chastened by the viral epidemics of the 1980s, has been marked by ongoing advances, including prophylaxis, immune tolerance induction, new drugs and gene therapy research. Current challenges include sustaining the comprehensive care model despite decreased funding and expanding the delivery and affordability of comprehensive haemophilia care.

Efficacy and safety of intravenous anti-D immunoglobulin (Rhophylac®) in chronic immune thrombocytopenic purpura

OBJECTIVES

This Phase III study examined the efficacy and safety of Rhophylac (CSL Behring AG, Bern, Switzerland), a highly pure, liquid-stable anti-D preparation, in chronic immune thrombocytopenic purpura (ITP).

MATERIALS AND METHODS

Ninety-eight patients (96 adults, two adolescents) with chronic ITP and platelet counts < 30 x 10(9)/l received a single intravenous injection of 50 microg/kg bodyweight Rhophylac.

RESULTS

A response (defined as an increase in platelet count by >or= 20 x 10(9)/l to >or= 30 x 10(9)/l in the first 15 days after treatment) was seen in 66% of patients. Mean time to response was 3.1 +/- 3.0 days, and mean duration of response was 19.2 +/- 1.1 days for responders. The most frequent drug-related adverse events were chills, pyrexia, an increase in bilirubin, and headache; events were mainly mild or moderate. there was no severe hemolysis or renal failure.

CONCLUSION

rhophylac is well tolerated and efficacious in chronic itp.

Another role for the VW molecule

My comments on the implication of the vW molecule in down-regulating the immunogenicity of factor VIII.

Can B-domain deletion alter the immunogenicity of recombinant factor VIII? A meta-analysis of prospective clinical studies

BACKGROUND

As a result of the infrequency of inhibitors in previously treated patients (PTPs) with hemophilia A and the small size of available clinical studies, the immunogenicity of factor (F)VIII products has been difficult to assess.

OBJECTIVES

A meta-analysis of prospective clinical studies was conducted to test the hypothesis that de novo inhibitor incidence differs between PTPs receiving full-length recombinant FVIII (FL-rFVIII) and B-domain deleted recombinant FVIII (BDD-rFVIII).

METHODS

Prospective studies with data on inhibitors in PTPs receiving FL-rFVIII or BDD-rFVIII were sought using systematic methods including bibliographic database searches. Data were secured from published study reports and inquiries to investigators. Between-group differences in inhibitor incidence rates were evaluated using mixed effects Cox regression.

RESULTS

Twenty-nine studies with 3012 total PTPs were included. Patients were at risk of de novo inhibitor development for a median of 79 exposure days. A total of 35 de novo inhibitors were observed. The cumulative hazard for all de novo inhibitors was 1.25% with a 95% confidence interval (CI) of 0.63-1.88%. The corresponding rate for high-titer de novo inhibitors [> 5 Bethesda units (BU)] was 0.29% (CI, 0.01-0.57%). Exposure to BDD-rFVIII was associated with an increased risk of all de novo inhibitors (hazard ratio, 7.26; CI, 2.12-24.9; P = 0.0016) and of high-titer de novo inhibitors (hazard ratio, 10.8; CI, 2.17-53.7; P = 0.0037), compared with FL-rFVIII.

CONCLUSIONS

This meta-analysis of prospective clinical studies suggests that recombinant FVIII products may differ in immunogenicity.

Harmonization of clinical trial guidelines for assessing the risk of inhibitor development in hemophilia A treatment

At the present time, the most significant complication of hemophilia therapy is the development of neutralizing antibodies (inhibitors) to factor (F) VIII, which adds greatly to the difficulty and expense of preventing and treating bleeding episodes. Both patient-related and therapy-related variables contribute to the development of inhibitors. The multifactorial nature of inhibitor development and the relatively small numbers of patients that participate in clinical trials make it difficult to accurately assess the risk of inhibitor development. Adding to that challenge is the lack of a uniform standard of design for conducting clinical trials to evaluate the safety of FVIII products. This hinders the comparison of products and is an obstacle to the meta-analysis necessary to make statistically valid assessments of inhibitor risk. This article reviews similarities and differences in clinical trial guidelines of European and US regulatory agencies and discusses the need for their harmonization to facilitate the assessment of FVIII products.

Evaluation of bleeding and thrombotic events during long-term use of romiplostim in patients with chronic immune thrombocytopenia (ITP)

BACKGROUND

Romiplostim is a peptibody protein that raises platelet counts during long-term treatment of patients with chronic immune thrombocytopenia (ITP). Clinical outcomes related to increased platelet counts include a reduced risk of bleeding and a potential risk of thrombosis.

OBJECTIVE

To evaluate bleeding and thrombotic events occurring in chronic ITP patients during two phase 3, randomized, placebo-controlled, 24-week studies of romiplostim and during subsequent treatment in an open-label extension study.

PATIENTS/METHODS

In the phase 3 trials, 125 patients were randomized to romiplostim or placebo; romiplostim dose was adjusted to maintain platelet counts of 50-200 x 10(9) L(-1). Patients who completed the phase 3 trials could enroll in the extension study in which all patients received romiplostim.

RESULTS

In the phase 3 trials, a significantly greater percentage of patients treated with placebo (34%) had bleeding adverse events of moderate or greater severity than did patients treated with romiplostim (15%, P = 0.018). In the extension study, the incidence of bleeding adverse events of moderate or greater severity decreased from 23% of patients in the first 24 weeks to 12% after 24-48 weeks, remaining < or = 6% thereafter. The exposure-adjusted incidence of thrombotic events was 0.1 per 100 patient-weeks in the phase 3 studies, and 0.08 per 100 patient-weeks in the extension study where patients received romiplostim for up to 144 additional weeks.

CONCLUSIONS

The incidence and severity of bleeding was decreased in chronic ITP patients treated with romiplostim compared with placebo, and the incidence of thrombotic events was not different between the two groups.

Factor IX and thrombosis

Fractionation technology has made Factor IX concentrates available. In addition to a very high incidence of hepatitis, thrombosis is being recognized as a consequence of their use. Contradictory reports exist in the literature as to the incidence of thrombotic events. A recent study of thrombohemorrhagic phenomena after infusion with Factor IX concentrates in patients with congenital Factor IX deficiency (hemophilia B) or liver disease, revealed an incidence of twenty episodes in 188 cases (11%). It is imperative to delineate the thrombogenic factors and find methods for their removal to insure the safety of Factor IX products.

Factor VIII inhibitor bypassing activity (FEIBA) - addressing safety issues

Bypassing therapy is usually necessary to control or prevent bleeding episodes in patients with haemophilia A or B and high-titre inhibitors. Factor VIII inhibitor bypassing activity (FEIBA) has a long history of successful use in the acute, surgical and prophylactic treatment settings, but safety concerns have made some reluctant to administer this bypassing agent. A review of the literature and clinical trial data show that FEIBA has a low prevalence of thrombosis, a low prevalence of anamnesis that does not impact haemostatic efficacy and an excellent record of pathogen safety and clinical tolerability.

Surgical interventions in a cohort of patients with haemophilia A and inhibitors: an experiential retrospective chart review

Strategies for the management of perioperative bleeding in patients with haemophilia and inhibitors have evolved rapidly as a result of the development of the bypassing agents Factor Eight Inhibitor Bypassing Activity, Anti-inhibitor Coagulant Complex (FEIBA) and activated recombinant factor VII (rFVIIa). However, there are currently no established guidelines for perioperative use of bypassing agents, and few controlled clinical studies have been carried out. Thus, case reports, such as those presented here, provide useful anecdotal evidence to guide the treatment of inhibitor patients. The purpose of this report was to describe experiences in the use of bypassing agents in a small cohort of patients with haemophilia A and inhibitors undergoing surgical procedures. Cases from five treatment centres were reviewed. Twenty-two procedures using FEIBA, rFVIIa or a combination of both agents were compiled from seven inhibitor patients (six with an alloantibody inhibitor and one with an acquired autoantibody inhibitor). Eleven procedures used FEIBA monotherapy, two employed rFVIIa monotherapy and nine were performed using combination therapy. Supplemental therapies were required to manage bleeding in some cases. Haemostatic control was achieved in all cases, and treatment regimens were generally well tolerated. One thrombotic adverse event was reported: evidence of disseminated intravascular coagulation (DIC) was found after rFVIIa use in one case, although the direct cause of DIC was unknown. The experiences in this case review demonstrate that both major and minor surgical procedures can be safely performed in patients with haemophilia and high-titre inhibitors under the cover of bypassing agents, with a high expectation of success.

Comparative thrombotic event incidence after infusion of recombinant factor VIIa versus factor VIII inhibitor bypass activity

Thrombosis is a rare but well-recognized potential complication of Factor VIII Inhibitor Bypass Activity (FEIBA) infusion. Recombinant factor VIIa (rFVIIa) is increasingly used as an alternative to FEIBA; however, the thrombotic safety profile of rFVIIa remains incompletely characterized. To determine the incidence rates of thrombotic adverse events (AEs) after infusion of rFVIIa and FEIBA. Data from the MedWatch pharmacovigilance program of the US Food and Drug Administration, as supplemented by published case reports, were used in conjunction with estimated numbers of infusions available from manufacturers to assess comparative incidence of thrombotic AEs in patients receiving rFVIIa or FEIBA in the period from April 1999 through June 2002. Reported thrombotic AEs were rare, with incidence rates of 24.6 per 10(5) infusions (CI, 19.1-31.2 per 10(5) infusions) for rFVIIa and 8.24 per 10(5) infusions (CI, 4.71-13.4 per 10(5) infusions) for FEIBA. Thrombotic AEs were significantly more frequent in rFVIIa than FEIBA recipients (incidence rate ratio, 2.98; CI, 1.71-5.52). The most commonly documented single type of thrombotic AE after rFVIIa infusion was cerebrovascular thrombosis, while myocardial infarction was the most frequent type in patients receiving FEIBA. Contrasting AE reporting patterns between rFVIIa and FEIBA may have contributed to the observed difference in thrombotic event incidence. Nevertheless, this comprehensive pharmacovigilance assessment does not support superior thrombotic safety of rFVIIa and suggests that thrombotic AE risk may be higher in rFVIIa than FEIBA recipients.

Liver biopsy in patients with inherited disorders of coagulation and chronic hepatitis C

Liver biopsy plays a pivotal role in the management of patients with a variety of liver diseases, including chronic hepatitis C virus. The major risk of the procedure is the potential for significant haemorrhagic complications. Although the data are limited, the procedure does not appear to pose excessive risk to the patient with inherited disorders of coagulation, provided that adequate haemostasis can be achieved prior to the liver biopsy. This requires close coordination of care between the hepatologist and the haematologist. Indications for liver biopsy should be the same in patients with haemophilia as in other populations.

The economic impact of factor VIII inhibitors in patients with haemophilia

The impact on the cost of care for haemophilia patients with inhibitors is not well defined. To quantify the effect on health care expenditures associated with inhibitors to factor VIII (FVIII) or FIX, we conducted a retrospective cohort study examining product use and outcomes in adult and paediatric haemophilia patients with and without inhibitors. Twelve patients with inhibitors to FVIII or FIX (cases) identified in the haemophilia surveillance system (HSS) at two centres were matched on age, severity of haemophilia, and treatment centre to haemophilia patients without inhibitors. Patients with HIV or significant liver disease were excluded from the study. All eligible non-inhibitor control patients were selected for inclusion in the study, resulting in a total of 28 controls. We then tracked product usage and hospitalizations from programme entry until 1998 or loss to follow-up, producing a total database of 184 person-years of experience. A descriptive matched analysis was conducted to examine annual differences in the cost of product used and hospitalizations. We found that the median cost for factor products among haemophilia patients with inhibitors was $55,853/year, $2,760 less than comparable haemophilia patients without inhibitors. The median number of hospitalizations per year was 1.0 for both inhibitor and non-inhibitor patients and the median number of days hospitalized was virtually the same. Although these findings do not appear to support the belief that there is a substantial increase in the cost of care for haemophilia patients with inhibitors, it does document that a few outlier patients can drive the cost of treatment for this disease. As the largest component of the cost of care is that of factor concentrate, it becomes imperative in the current health care environment to better define the true costs and benefits of treatments designed to eradicate or manage inhibitors. A careful cost accounting of immune tolerance induction (ITI) and other therapeutic strategies, taking into account successes and failures and duration and intensity of therapy, should help to better define the costs and benefits of such approaches. Methods to identify high cost inhibitor patients should be developed so that these strategies may be targeted to appropriate candidates.

Factors predictive of death among HIV-uninfected persons with haemophilia and other congenital coagulation disorders

Historically, the leading cause of death among persons with haemophilia and other congenital coagulation disorders was uncontrolled bleeding. Mortality was associated with severe deficiency of coagulation factors VIII or IX and especially with high-titre antifactor neutralizing antibodies (inhibitors). The catastrophic contamination of plasma donor pools with human immunodeficiency virus (HIV) resulted in acquired immunodeficiency syndrome replacing haemorrhage as the leading cause of death among persons with haemophilia. Rather little has been written, however, about mortality among those not infected with HIV. The objective of this study was to identify conditions associated with all-cause mortality among HIV-uninfected patients who were followed for a mean of 8.8 years in the Multicentre Hemophilia Cohort Study. Among the 364 children (mean age 8 years), there were four deaths; two related to cancer, one to trauma, and the fourth to haemorrhage, end-stage liver disease and sepsis. Among the 387 HIV-uninfected adults (mean age 35 years) there were 29 deaths, with haemorrhage the leading cause of death, followed by hepatic, stroke and cancer deaths. Prognostic factors for all-cause mortality among the adults included haemophilia Type A with neutralizing antibodies [age-adjusted relative rate (RR) 3.1, 95% confidence interval (CI) 1.4-6.9] and serologic evidence of both hepatitis B and C virus (RR 4.1, 95% CI 0.97-17.6). Although hepatitis C viral load was slightly lower in patients with hepatitis B virus surface antigenaemia, it was unrelated to vital status. We conclude that causes of death and prognostic factors for current HIV-uninfected haemophilia patients are similar to those noted before the HIV epidemic. Better understanding, prevention and control of neutralizing antibodies and hepatitis infections may substantially improve longevity for people with haemophilia.

Unexpected bleeding disorders

Patients with known coagulation deficiencies, either congenital or acquired, may bleed spontaneously with trauma or with surgical intervention. In contrast, however, are the unchallenged patients who bleed in a variety of clinical settings that demand rapid diagnosis so that appropriate therapy can be instituted. In the first section Dr. Louis M. Aledort demonstrates a series of vignettes of actual cases who presented with unexpected bleeding or a screening laboratory abnormality prior to a needed surgical intervention. Settings include dental, oral surgical, obstetrical, surgical and gynecological. The differential diagnoses of these cases are discussed. In the second section Dr. David Green also uses vignettes to demonstrate how the laboratory is used to differentiate the various clinical entities. The choice and priority of required tests indicated by the settings, history, site and type of bleeding, and the syllogisms used to define the abnormality are stressed. In the third section, Dr. Jerome Teitel reviews in detail the therapeutic armamentarium available to the clinician and presents algorithms for the management of these bleeding disorders.

The role of porcine factor VIII in the management of unexpected bleeding episodes

The introduction of porcine factor VIII (pFVIII) has been an important addition to our armamentarium in the management of patients with inhibitors to FVIII. Case studies will be presented that offer important differential diagnoses. The prevalence and indications for the use of this biological replacement therapy will be discussed.

Leukemia after liver transplant

INTRODUCTION

Acute leukemia is rare after solid organ transplantation.

METHODS

Review of data on 3 patients with acute leukemia identified among 1365 who underwent liver transplantation at our center, and a review of the literature.

RESULTS

In patient 1, AML-M4 developed 19 months after transplant for cryptogenic cirrhosis. In patient 2, B cell acute lymphoid leukemia was diagnosed 10 months after liver transplant for fulminant hepatitis. Both patients had normal cytogenetics, and achieved complete remission with chemotherapy. In patient 3, acute monocytic leukemia-M3 with t(15;17) arose 18 months after transplant for hepatitis C cirrhosis. This patient received treatment with retinoic acid and chemotherapy, but developed a disseminated intravascular coagulation and died before completing therapy. No patient presented with chromosomal abnormalities commonly seen in secondary leukemia. The latency period to diagnosis after transplant was 10-19 months.

CONCLUSIONS

Acute leukemia, although rare after liver transplantation, should be considered in the differential diagnosis of hematological complications.

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.

Factor VIII inhibitors. Immune tolerance induction: is it cost effective? We know too little

The development of an inhibitor in a hemophiliac is a serious clinical problem. Many inhibitors have high titers, and thus one cannot guarantee hemostasis. The prevalence of this transfusion-transmitted disease reaches as high as 35%, even with newer products. The costs of product use for inhibitor patients are significantly higher than for those without an inhibitor. For more than 20 years, using the concept of antigen overload, several regimens have existed for the induction of immune tolerance to eradicate these inhibitors. Registries exist reviewing the results of these regimens in the United States and internationally. Although much has been garnered about predictors of outcomes, we have much to learn about who the ideal candidates are, what optimal regimens are, and when to stop, as well as how to maintain a success. The costs of managing an inhibitor patient with and without human immunodeficiency virus (HIV) have caused managed care programs to seriously challenge the use of these regimens. Data are needed to provide the cost benefit of immune tolerance.

Making a therapeutic choice: human versus recombinant fractions - can we do it?

New manufacturing methods have resulted in production of higher purity human-derived products and recombinant factors with less human- or animal-derived reagents or stabilizers for the treatment of congenital coagulation disorders. In addition, new viral inactivation processes are being used to reduce the chance of viral contamination. Preferred treatment approaches are moving toward using newer-generation agents. At the same time, rationale exists for continuing fractionation of all types of products, based on considerations including cost, product availability, safety issues, and specific clinical situations for which a recombinant or high-purity product is not available. These issues and others are reviewed in the context of making a therapeutic choice.

Obstetrical and gynaecological bleeding: a common presenting symptom

Excessive haemorrhage is one of the commonest symptom when women present to obstetricians and gynaecologists. In the majority of cases the cause is related to the primary obstetric and gynaecological pathology and is easily identified. However, less commonly, the bleeding is unexpected and due to an undiagnosed underlying coagulation defect, the commonest of which is von Willebrand (vWD) disease. Menorrhagia is a common, and may be the only, clinical manifestation of an inherited bleeding disorder. Screening 150 women with menorrhagia, vWD was diagnosed in 13% of patients and other hereditary haemorrhagic disorders in another 4%. Menorrhagia with onset at the menarche was predictive of an inherited bleeding disorder in 65% of vWD and 67% of FXI deficient patients. Therefore, testing for bleeding disorders should be considered in women with menorrhagia especially those with early onset and no obvious pelvic pathology. Childbirth and puerperium present a special risk for excessive haemorrhage. The risk of postpartum haemorrhage is very high in women with inherited bleeding disorders. In our centre, the incidence of primary and secondary postpartum haemorrhage was 22% and 11% in carriers of haemophilia 18.5% and 20% in vWD and 16% and 24% in FXI deficient women, respectively. Acquired haemophilia can be an unusual cause of severe and unexpected postpartum haemorrhage with a very high mortality rate. Unexplained postpartum and postoperative haemorrhage that does not respond to general measures should alert clinicians to the possibility of bleeding disorders as a causative factor. In addition, increased awareness among obstetricians and gynaecologists of these less common causes and close collaboration with the local haemophilia centre and availability of management guidelines are essential for optimal outcome.