Safety and efficacy of KOGENATE Bayer in previously untreated patients (PUPs) and minimally treated patients (MTPs)

Safety and efficacy of KOGENATE Bayer (Kogenate FS), a second-generation full-length recombinant factor VIII formulated with sucrose as stabilizer and produced without the addition of human albumin during purification and the final formulation, was assessed in a prospective, international clinical trial including 31 previously untreated patients (PUPs) and minimally treated patients (MTPs) with severe haemophilia A in home therapy and surgery. Factor VIII inhibitor development was monitored and mutation type profiles were analysed. As of 30 June 2000, the patients received a total of 2.729 infusions (mean 88; range 6-274) for bleeding episodes, surgery or prophylactic treatment. No unexpected drug-related adverse events were observed. Four patients developed an inhibitor after 3-12 exposure days (EDs). One patient successfully underwent immune tolerance treatment; inhibitors in two patients disappeared spontaneously with on-demand treatment, while the inhibitor titre remains low in one patient. Twenty-nine patients (93%) with more than 20 EDs can be regarded as at low risk for inhibitor development. In conclusion, KOGENATE Bayer is efficacious and well-tolerated for treatment of children with severe haemophilia A. The incidence of inhibitor formation is not different to that observed with other recombinant or plasma-derived products.

Factor VIII and transmissible spongiform encephalopathy: the case for safety

Haemophilia A is the most common inherited bleeding disorder, caused by a deficiency in coagulation factor VIII (FVIII). Current treatment of haemophilia A is based on repeated infusions of plasma-derived FVIII concentrate or of recombinant FVIII, which may be exposed to plasma-derived material of human or animal origin used in its tissue culture production process. We review epidemiological and experimental studies relevant to blood infectivity in the transmissible spongiform encephalopathies (TSEs, or 'prion' diseases), and evaluate the hypothetical risk of TSE transmission through treatment with plasma-derived or recombinant FVIII.

Efficacy and safety of the factor VIII/von Willebrand factor concentrate, haemate-P/humate-P: ristocetin cofactor unit dosing in patients with von Willebrand disease

The present study was initiated to evaluate the safety and efficacy of Haemate-P (Humate-P in North America) (anti-hemophilic FVIII/VWF complex [human] dried, pasteurized) dosed in ristocetin cofactor units (VWF:RCo) in the treatment of von Willebrand disease (VWD) patients in Canada. This retrospective data collection reviewed the medical records of VWD patients treated under the Canadian Emergency Drug Release Program from November 22, 1991, to April 30, 1996. Data collection was accomplished by on-site retrieval from source data for 97 patients. Dosing was based on the German package insert, which lists only Factor VIII:C (FVIII:C) units, which were converted in the study analysis to VWF:RCo units based on the analysis of the individual manufactured lots of product used in these patients (average ratio of 2.6 IU VWF:RCo per IU FVIII:C). Twenty five different lots of Haemate-P/Humate-P were used to treat 437 different events in the 97 study patients (344 hemorrhagic events, 73 surgical interventions and 20 prophylactic infusion cycles). Overall, the median dose of concentrate per infusion used to treat surgical events was 69.1 IU VWF:RCo/kg (range 11.9-222.8); bleeding events 55.3 IU VWF:RCo/kg (range 17.1-227.5) and prophylaxis 41.6 IU VWF:RCo/kg (range 34.6-81.0). Treatment periods varied, with the majority of events treated for < or = 10 days (91%). Fifty percent of events that were treated longer than 10 days were given for prophylactic reasons. Efficacy was determined in a standardized manner by the physician, based on dosing in VWF:RCo activity. An overall clinical result of "excellent" or "good" was reported in 97% (424/437) of treatment events. A pediatric sub-population analysis of the patient population reported "excellent/good" efficacy in 100% (17/17) of treatment events in infants, 95% (155/164) in children, and 94% (76/81) in adolescent patients. Related adverse events (AEs) were observed in only 4 (4%) patients and were not deemed to be serious. The findings in this study confirm the safety and efficacy of Haemate-P/Humate-P using VWF:RCo dosing in pediatric and adult patients with various types of VWD.

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.

Porcine factor VIII: current status and future developments

High-purity porcine factor VIII (pFVIII) (Hyate:C, Ipsen, UK), with a specific activity of > 125 U mg(-1) protein, has been shown to be effective in up to 90% of bleeds in patients with FVIII inhibitors. These inhibitors have been shown to have a median 15% cross-reactivity to pFVIII, and even less cross-reactivity in patients with acquired haemophilia. Its use is sometimes associated with a transient fall in platelet count and with transfusion reactions. Furthermore, it is not virally attenuated. Although pFVIII has not been shown to transmit any viral illness to its human recipients, it is extensively screened for porcine viruses using a 4-cell line general screen. The source plasma is also screened for porcine parvovirus. To satisfy the demand for ever-improved side-effect profile and viral safety a third-generation pFVIII is under consideration by Ipsen. This product will be purified from porcine plasma screened for porcine parvovirus, using immuno-purification, ion-exchange chromatography and washing. Spiking experiments using human FVIIIC (hFVIIIC) suggest that these purification steps may be associated with a 6-log viral reduction. The product is also virally attenuated using the solvent-detergent method. This should yield an ultra-pure concentrate, lacking porcine von Willebrand factor, with a specific activity of approximately 5000 U mg(-1) protein which does not require added albumin as stabilizer and which may be stored at 2-4 degrees. One would anticipate that this product should be clinically effective and should be associated with enhanced viral safety and an improved side-effect profile. It should not affect the platelet count and should be associated with a much reduced risk of transfusion reactions. Clinical trials are planned.

Ricky Ray Hemophilia Relief Fund Program. Adoption of interim final rule as final rule with amendments

This document adopts the Ricky Ray Hemophilia Relief Fund Program interim final rule as a final rule with amendments. This final rule facilitates the petitioning process where health care history can be certified by physician assistants as well as by physicians or nurse practitioners; details the procedures by which the Secretary may resolve issues of eligibility or payment raised by a petition; ensures that payments made for the benefit of minors and other individuals who do not have the legal capacity to receive the payments are used for their benefit; and allows additional time for petitioners who are having difficulty obtaining needed medical or legal documentation to complete their petitions.

[High concentration of coagulation factor VIII as a risk factor for thrombosis]

Several case-control studies have shown that factor VIII levels > or = 150 IU/100 ml lead to a greatly increased risk of venous thrombosis. High levels of factor VIII are also associated with an increased risk of recurrences of thrombosis. The prevalence of high factor VIII levels is 25% in patients with a first episode of venous thrombosis and 11% among healthy controls. The contribution of high factor VIII levels to the onset of venous thrombosis in the population is 16%. The mechanism causing high factor VIII levels is largely unknown and probably consists of both genetic and acquired factors. At present, the routine screening of thrombosis patients for high factor VIII levels is not recommended.

Purity of factor VIII product and incidence of inhibitors in previously untreated patients with haemophilia A

It has been suggested that ultrapure clotting factor products carry a greater risk for inhibitor development in patients with haemophilia. We compared the incidence of inhibitors in 59 previously untreated patients (PUPs) with severe haemophilia (endogenous factor VIII < 0.01 U L-1) A, who were initially treated with cryoprecipitate or intermediate purified products, with that in 22 patients exclusively treated with monoclonally purified and recombinant factor VIII. Persistent inhibitors were those with 1 Bethesda unit per mL or more, on more than one occasion, combined with a decrease in recovery. Incidences of persistent inhibitors were 17% (10/59) for patients who were treated with cryoprecipitate or intermediate-purity products and 9% (2/10) for monoclonally purified and recombinant factor VIII. Transient inhibitors appeared to develop earlier during treatment with ultrapure products as compared to treatment with intermediate/low-purity products. In conclusion, ultrapure products appear not to carry a higher risk for inhibitor development.

Management of von Willebrand disease: a survey on current clinical practice from the haemophilia centres of North America

The optimal treatment of patients with von Willebrand's disease (vWD) remains to be defined. Moreover, it has not been firmly established which, if any, commonly measured parameters of von Willebrand factor (vWF) protein in the plasma are useful in guiding treatment. To better understand what guidelines physicians follow in the management of vWD, we surveyed 194 North American physicians who are members of the Hemophilia Research Society. Ninety-nine per cent of responding physicians depend on factor VIII (FVIII):C, vWF:RCo activity and vWF:AG to diagnose vWD, while only 49% use the bleeding time. The minimal goals of treatment for patients undergoing major surgery/trauma or central nervous system haemorrhage were FVIII:C and vWF:RCo activity greater than 80% while levels of more than 50% for minor surgery and dental extractions were considered adequate. Treatment of vWD was based on the type of vWD with type 1 patients being treated most often with desmopressin acetate (DDAVP) alone, types 2A and 2B patients with a combination of DDAVP and a vWF-containing FVIII product, type 3 patients with vWF-containing concentrate. Viral infections, including human immunodeficiency virus, hepatitis A, B and C viruses, and parvovirus have been seen in vWD and the efficacy of viral attenuation processes is a major criterion for the selection of treatment by physicians. Based on this survey, prospective studies need to be designed to address the clinical efficacy, safety and predictive value of laboratory monitoring of patients with vWD.

Anaphylaxis in patients with hemophilia

Anaphylactic reactions are rare emergencies observed in hemophilia patients. In hemophilia (B) (HB) patients they typically occur coincident with the development of an inhibitor. It is important to be aware of the possibility of such reactions, and the patient's family should be educated at the time of initial diagnosis and discussion. Because these reactions typically occur within the first 10 to 20 treatment courses, the first few infusions should be given in a hospital/clinic setting equipped to manage such emergencies. Obtaining the exact genotype may identify the HB patients at risk for this complication. When immune tolerance induction (ITI) is attempted in patients with HB inhibitors and anaphylaxis, the physician should be vigilant in detecting proteinuria.

Evidence of porcine endogenous retroviruses in porcine factor VIII and evaluation of transmission to recipients with hemophilia

Since 1984, unheated porcine clotting factor VIII (Hyate:C) has been used to treat severe bleeding episodes in persons with hemophilia who have antibodies to human clotting factor. We document the presence of porcine endogenous retrovirus (PERV) in plasma samples of pigs and in clinical lots of Hyate:C. Both gag and pol PERV RNA sequences were detected by reverse-transcriptase (RT) polymerase chain reaction in 13 of 13 lots of Hyate:C tested. Among 10 of these lots, RT activity also was detected, which confirms the presence of retroviral particles. To assess the transmission of PERV to Hyate:C recipients, we tested serum specimens from 88 recipients of Hyate:C and 23 noninfused control subjects for anti-PERV antibodies by using a Western blot assay. None of the samples was positive. Our data document that PERV particles are a common contaminant of Hyate:C products and suggest that the risk of PERV transmission from these percutaneous exposures is very low.

Characterization of high-risk HIV-1 seronegative hemophiliacs

Mechanisms that protect most high-risk HIV-1 seronegative (HRSN) persons are not well understood. Among hemophiliacs from the Multicenter Hemophilia Cohort Study who remained HIV-1 seronegative despite a high (94%) risk for acquisition of HIV-1 infection, only 7/43 were homozygous for the protective CCR5 Delta32 polymorphism. Among the remainder, neither CCR5 density nor beta-chemokine production, nor in vitro susceptibility to infection with the HIV-1 isolate JR-FL could distinguish HRSN hemophiliacs from healthy controls. When compared to lymphocytes of healthy controls not at risk for HIV-1 infection, diminished spontaneous lymphocyte proliferation was seen in lymphocytes of HRSN hemophiliacs as well as in lymphocytes of hemophiliacs not at risk for HIV-1 infection. Surprisingly sera/plasmas obtained from high-risk HIV-1 seropositve hemophiliacs prior to seroconversion more often contained alloreactive antibodies than date-matched sera/plasmas obtained from HRSN hemophiliacs. Thus alloreactivity may predispose to acquisition of HIV-1 infection after parenteral exposure.

Current status of hemophilia patients and recombinant coagulation factor concentrates in Japan

The first recombinant factor VIII concentrate was introduced in 1987 to treat hemophilia A patients, and the product was licensed in the United States in 1992. More than 10 years have passed since the recombinant products have been used for treatment of hemophilia A. The new therapeutic options seem to be safe and effective through the gathered experiences. Recently, recombinant factor VIIa concentrate has become available to treat hemophilia patients with inhibitor and factor VII deficiency patients in Europe and also recombinant factor IX for the treatment of hemophilia B has been licensed in the United States and Europe. The usage of recombinant coagulation factors has expanded the routine therapy for hemophilia in many countries. In Japan, the consumption of recombinant factor VIII is increasing year by year, because many patients have started to think that the recombinant technology seems to be safe. Unfortunately, though, the factor VIIa and factor IX products have not been licensed yet in Japan. This article discusses the current status of patients with hemophilia and recombinant coagulation factor products in Japan.

Possible association between cytomegalovirus infection and gastrointestinal bleeding in hemophiliac patients

Cytomegalovirus (CMV) infection is of major concern in immunocompromised and immunosuppressed patients. Prior to the introduction of HIV-1 antibody screening and efficient virucidal processes to inactivate viruses, individuals with a factor VIII or factor IX deficiency had a high risk of contracting HIV-1 infection through the infusion of contaminated blood products. In addition, blood products were also frequently associated with alterations in immune function. This study investigated the frequency of active CMV infection and its clinical relevance in Brazilian hemophiliacs. One hundred hemophiliacs were screened for the presence of CMV-DNA in their blood using nested PCR. Twenty-five out of 100 patients (25%) were positive for CMV-DNA and 24 of these 100 patients (24%) were HIV-1 positive; 6 of these 24 (25%) were positive for CMV-DNA. A similar frequency was observed among HIV-1-negative patients. In 60 hemophiliacs, the clinical relevance of the CMV infection was assessed. Twenty-one patients were positive for CMV-DNA. Of these, 10 had gastrointestinal bleeding compared to only 9 of 39 patients who were CMV-DNA negative (p = 0.05; chi(2) test). These data indicate a high prevalence of active CMV infection in Brazilian hemophiliac patients, irrespective of whether the patients were or were not infected by HIV-1. There was a possible association between the presence of CMV and the occurrence of gastrointestinal bleeding.

Immune tolerance in a haemophilia A patient with high inhibitor using locally prepared lyophilized cryoprecipitate

The immune tolerance in a 12-year-old haemophilia A patient was carried out at the Faculty of Medicine, Ramathibodi Hospital, Bangkok in 1998. His inhibitor titres ranged from 10 to 3450 Bethesda units (BU). He suffered from serious bleeding episodes requiring prolonged hospitalization and the disarticulation of the left knee joint. After obtaining informed consent, locally prepared lyophilized cryoprecipitate (LC), heat treated at 60 degrees C for 25 h, was given in a dose of 13 units kg-1 body weight of factor VIII three times per week. His inhibitor was increased from 15 to 580 BU within the first 4 weeks of immune tolerance. Finally, it was decreased to 40 BU in the 36th week. The only adverse effect was seroconversion of anti-hepatitis C virus after receiving 108 bottles of LC for 36 weeks. In conclusion, the locally prepared LC was able to control the bleeding episodes in a haemophilia A patient with high inhibitor. To our knowledge, this is the first reported case in Thailand.

Porcine factor VIII provides clinical benefit to patients with high levels of inhibitors to human and porcine factor VIII

The development of an inhibitor against Factor VIII is an important complication of haemophilia and occurs in approximately 31% of patients [1]. Despite various approaches to their management, the presence of these inhibitors remains a major cause of morbidity and mortality. Inhibitors may be low level [<5 Bethesda Units (BU)] or high level [>10 BU]. Low-level inhibitors usually remain low and do not respond to administered factor VIII with a rise of the inhibitor titre; high-level inhibitors, in contrast, are characterized by a rapid rise in titre following treatment with factor VIII. Modalities of treatment of acute bleeding episodes in patients with inhibitors include 'overcoming' the inhibitor with very large doses of factor VIII, 'bypassing' the inhibitor blockade with products such as activated prothrombin complex concentrates or recombinant factor VIIa, 'removing' the inhibitor by plasmapheresis or immunoabsorption and 'repressing' it with immunosuppressive drugs and immune tolerance induction. An alternative approach is to use a porcine factor VIII concentrate which does not cross-react with the human factor VIII inhibitor. Following treatment with porcine factor VIII, functional factor VIII can be detected and the therapeutic levels correlate with cessation of bleeding. The use of porcine factor VIII may, however, result in the development of antiporcine factor VIII antibodies, limiting its use. Experience in patients with high-titre inhibitors indicates that porcine factor VIII therapy could be used in the presence of factor VIII inhibitors [2-11], including inhibitors to porcine factor VIII [5,7], and that haemostasis may be obtained in the absence of detectable levels of circulating factor VIII [7,11].

Recombinant FVIIa (NovoSeven) continuous infusion and total hip replacement in patients with haemophilia and high titre of inhibitors to FVIII: experience of two cases

In this report we describe our experience of total hip replacement in two patients with severe haemophilia A and high titres of inhibitors to FVIII. We used rFVIIa replacement therapy by continuous infusion to perform the surgery. The total amount of rFVIIa used in these two patients was very similar but the manner of administration was quite different. In our experience, it is an advantage to use a higher dose for shorter periods than a lower dose for a longer treatment period. Tranexamic acid by continuous infusion, and parallel saline infusion were useful for good haemostasis and avoided local thrombophlebitis in the side of rFVIIa infusion.

Immune tolerance for haemophilia patients with inhibitors: analysis of the western United States experience. The Tri-Regional Nursing Group

The experience with immune tolerance (IT) induction therapy for haemophilia patients with inhibitors, instituted during 1990-97 at 17 haemophilia treatment centres in the western United States, was reviewed. IT was instituted in 104 of 139 (75%) of all identified haemophilia A and haemophilia B patients with inhibitors. Doses and schedules for IT varied but most patients were treated with a daily administration of 25-200 units kg-1 day-1. Successful immune tolerance (defined as Bethesda Unit titres < 1.0) was achieved in 57 of 81 (78%) patients who completed therapy. IT success was significantly greater for those patients with historic titres < 100 BU (P < 0.0003) and those with titres of < 10 BU at initiation of IT (P < 0.0001). IT success was uniformly achieved in 16 patients with low to moderate responding inhibitors. IT in infants < 2 years of age was problematic due to the presence of high titre inhibitors and complications of venous access. Frequent complications of IT included increased bleeding during intravenous access device insertion (20%) and infections associated with venous access devices (64%). IT is widely accepted as a treatment modality for haemophilia patients with inhibitors. Patient participation in IT regimens and management during therapy is facilitated greatly by the efforts of treatment centre nurse coordinators who are knowledgeable about haemophilia and its complications. Additional clinical trials will be necessary to define better initial dose, schedule, dose adjustment and success/failure criteria for IT.

Acute left anterior descending artery occlusion in a hemophiliac A patient during recombinant factor VIII infusion: treatment with coronary angioplasty

Acute myocardial infarction in association with the replacement of recombinant factor VIII in hemophiliacs has not been documented. We describe the use of PTCA in a hemophiliac A patient who developed acute myocardial infarction during factor VIII replacement. Because surgery in hemophiliac A patients remains hazardous, PTCA seems to be an attractive alternative.

Coagulation products and their uses

The indications, pharmacokinetics, and therapeutic guidelines for available coagulation products are reviewed. Patients with hemophilia, von Willebrand's disease (VWD), or acquired inhibitors to antihemophilic factor (AHF) cannot spontaneously stop an acute hemorrhage. Coagulation products used to manage bleeding in patients with these disorders include AHF concentrates, factor IX concentrates, factor VIIa concentrate, factor IX complexes, anti-inhibitor coagulant complexes, and desmopressin acetate. Typically, these commercially available products are used to manage acute bleeding or to prevent excessive bleeding during surgery. The dosage of the coagulation products and the duration of therapy depend on many variables, including the severity of the hemorrhage, the pharmacokinetics of the coagulation products, and patient-specific factors. Product purity and viral attenuation are also important considerations in determining an appropriate dosage regimen. Recombinant versions of some coagulant factors are available and can eliminate the risk of viral transmission. A thorough understanding of each coagulation product can guide product selection, dosing, and treatment duration and can reduce the risk of viral transmission.

Sucrose formulated recombinant human antihemophilic factor VIII is safe and efficacious for treatment of hemophilia A in home therapy--International Kogenate-FS Study Group

To add an increased level of safety to antihemophilic factor replacement therapy, a full-length, recombinant Factor VIII (rFVIII) product has been developed without human-derived plasma proteins during purification and formulation and using an additional solvent/detergent viral inactivation step. This first clinical trial of a sucrose-formulated full-length rFVIII (rFVIII-FS) was conducted in previously treated patients (> or = 100 prior exposure days) with severe (<2% FVIII) hemophilia A in North America (NA) and Europe (EU). Pharmacokinetic profiles for rFVIII-FS were compared with those of currently licensed rFVIII product (Kogenate) in 35 patients. Safety and efficacy during home therapy were evaluated in 71 patients. The new formulation displayed a pharmacokinetic profile similar to that of rFVIII. Patients on home therapy received a cumulative total of 11,867 exposure days, 12,546 infusions, and 22,443,694 IU of rFVIII-FS. Of 2585 bleeds, 93.5% were treated with 1-2 infusions and 80.5% of responses were rated as excellent or good. No evidence of de novo inhibitor formation was observed. Only 0.27% of infusions were associated with any drug-related adverse event. Except for an episode of intermittent chest pain with palpitations which ceased after treatment with analgesics, associated adverse events were mild or moderate. Overall, rFVIII-FS provided excellent hemostatic control, was well-tolerated, and caused no significant adverse effects, thus demonstrating safety and efficacy for treatment of bleeds in patients with hemophilia A.

Investigation of porcine parvovirus among persons with hemophilia receiving Hyate:C porcine factor VIII concentrate

BACKGROUND

Porcine clotting factor has been used for more than 15 years to treat severe bleeding episodes in persons with hemophilia who have antibodies to human clotting factor. In 1996, QC procedures revealed for the first time the presence of porcine parvovirus (PPV) in the product. This report describes an investigation to determine the extent of product contamination and to evaluate past recipients of porcine clotting factor (Hyate:C, Speywood Biopharm) for evidence of PPV infection.

STUDY DESIGN AND METHODS

Stored specimens from 22 lots of previously released Hyate:C were tested for the presence of PPV DNA by PCR and nested PCR assays. Serum specimens from 98 recipients of Hyate:C and 24 controls who did not receive Hyate:C were tested for PPV antibodies by an immunofluorescence assay.

RESULTS

PPV DNA was detected in product from 21 of the 22 lots of Hyate:C, primarily by nested PCR testing. In contrast, none of the serum specimens from the 98 Hyate:C recipients tested positive for PPV IgG antibodies.

CONCLUSION

The risk of human disease from percutaneous exposure to low levels of PPV seems to be low. Nevertheless, the theoretical risk of human infection with PPV has led to manufacturing changes, including PCR screening of all porcine plasma, which are designed to eliminate this risk.

Prevalence of human parvovirus B19 and TT virus in a group of young haemophiliacs in South Africa

A well recognized hazard of transfusion with blood or blood products is the acquisition of a viral infection. Parvovirus B19 and transfusion transmitted virus (TTV) are two of several non-enveloped viruses that may on rare occasions be present in coagulation factor concentrates. The prevalence of these viruses in the South African Haemophilia population has not previously been studied. Thirty-nine Haemophiliac children were investigated for evidence of parvovirus and TTV infection. 26 boys with Haemophilia A had been treated with cryoprecipitate or intermediate purity factor VIII, and 13 boys with Haemophilia B had received prothrombin complex concentrates. All the plasma products were prepared from South African donors and were virally inactivated by heat or solvent/detergent since 1992. A control group of 32 children who had not been transfused were also studied. IgG antibodies to B19 were present in 29 of the 39 patients (74%), 18/26 (69%) with Haemophilia A and 12 of the 13 (85%) with Haemophilia B. None of the patients was IgM antibody positive but two children were PCR positive for B19 DNA. Of the control children, 47% had IgG antibodies to B19, but none were IgM antibody or B19 DNA positive. TTV viral DNA was found in 10.2% of patients and in 9% of the control group. The results indicate that our locally produced plasma products are not a significant source of TTV transmitted infection but may contribute to infection by B19 parvovirus.

Portal vein thrombosis in a patient with severe haemophilia A and F V G1691A mutation during continuous infusion of F VIII after intramural jejunal bleeding--successful thrombolysis under heparin therapy

We report on a 14-year-old boy with severe haemophilia A who developed a portal vein thrombosis during continuous infusion of F VIII. For treatment of a posttraumatic intramural jejunal haematoma with extension into the mesenterium the patient received continuous infusion (CI) of a high purity F VIII concentrate, starting with an initial bolus injection of 100 IU F VIII/kg bw and followed by 4-5 IU F VIII/kg bw/h i.v. F VIII plasma activity ranged between 47 and 88%. Resorption of the haematoma was proven by abdominal ultrasonic follow-ups. After 3 weeks of CI a thrombus formation in the portal vein was detected by ultrasound and confirmed by duplex ultrasound. Subsequent to diagnosis the patient was heparinised with unfractionated heparin (UFH 300-450 IU/kg/d i.v.). In order to induce further resorption of the haematoma. F VIII concentrate was given concomitantly (50 IU/kg bw twice daily) during the initial phase of treatment. After 14 days of anticoagulant therapy with UFH, the regimen was changed to low molecular weight heparin (LMWH; Fraxiparin 0.3; 2850 IU anti-X activity/d s.c.; bw 60 kg). F VIII dosage was gradually reduced with advanced resorption of the haematoma and thereafter switched to prophylaxis (40 IU/kg bw 3 times weekly). Complete lysis of the thrombus was observed after 6 months of treatment with UFH and LMWH respectively without any further complications. Thereafter LMWH was discontinued. Thrombophilic screening revealed no abnormalities except heterozygous F V G1691A.

CONCLUSION

The coexistence of a common prothrombotic risk factor and haemophilia may cause severe complications, in particular if the bleeding disorder has to be corrected temporarily by administration of the concerning deficient agent.

Pharmacokinetics of recombinant factor VIII (recombinate) using one-stage clotting and chromogenic factor VIII assay

In a study designed to demonstrate the safety and pharmacokinetics of a recombinant factor VIII (Recombinate) manufactured in Andover, MA and Thousand Oaks, CA, two different methods of factor VIII assay (one-stage clotting and Chromogenic substrate) were compared in vivo. The study was performed in four centres in the UK: London, Oxford, Cardiff and Manchester. Two pharmacokinetic studies, at least one week apart, were performed in 30 patients with severe haemophilia A (VIII:C < 2 IU/dl). A dose of 50 IU/kg was administered with sampling pre-infusion, and +0.25, 0.5, 1, 3, 6, 9, 12 and 24 h post-infusion. The aggregate 60 pharmacokinetic study showed a half-life of 12.7 and 13.0 h (p = 0.28) and recovery of 127 and 161 IU/dl (p = 0.0001) using one-stage clotting or chromogenic substrate respectively. In a supplementary experiment, 20 post-infusion samples were re-assayed by 1-stage and chromogenic assay using two plasma (20th British plasma standard and an "in-house" pooled normal plasma) and two concentrate standards, derived from the same type, but different batch of infused concentrate (Recombinate) and pre-diluted in either individual pre-infusion sample or in pooled commercial haemophilic plasma. The use of the Recombinate concentrate standard overcame the significant difference in FVIII levels between 1-stage and chromogenic assay methods when a plasma standard was used (p <0.0001). It is concluded that where potency dosing designation is carried out by an assay system different to that used in the clinical situation, the use of the recombinant concentrate as a standard in post-infusion plasma samples is likely to give more reliable and reproducible results.

Recurrent spontaneous intracerebral hemorrhage in a congenitally afibrinogenemic patient: diagnostic pitfalls and therapeutic options

BACKGROUND

Coagulation disorders can cause intracerebral bleeding that may be difficult to detect since subsequent aberrant clot formation may mask early detection. This is an important pitfall because, when diagnosed early, bleeding in these patients is treatable.

CASE DESCRIPTION

A patient with congenital afibrinogenemia presented with recurrent hemiparesis. Spontaneous intracerebral hemorrhage was diagnosed, despite an initial negative CT scan. Diagnosis, therapy, and complications of therapy are discussed.

CONCLUSIONS

Intracerebral hemorrhage must be strongly suspected in any patient with a coagulation disorder presenting with matching clinical symptoms. Therapy must be installed immediately, before additional investigations, and should be continued even when initial neuroimaging is negative.

Human recombinant DNA-derived antihemophilic factor (factor VIII) in the treatment of hemophilia A

BACKGROUND

Plasma-derived factor VIII concentrates used in the treatment of hemophilia A have the potential danger of transfusion-associated viral disease. The safety and efficacy of a recombinant factor VIII preparation for the treatment of this disorder were evaluated in this study.

METHODS

We compared the pharmacokinetics of plasma-derived and recombinant factor VIII in 12 previously treated subjects with severe hemophilia A.

RESULTS

The recovery and elimination half-lives of the recombinant factor VIII were equal to those of plasma-derived factor VIII. It was well tolerated via parenteral therapy, and only two mild adverse reactions (5%) were reported. No evidence of new viral infection was noted during the study period with the recombinant factor VIII.

CONCLUSIONS

The biologic activity of the recombinant factor VIII is comparable with that of plasma factor VIII concentrate. It is safe and efficacious for the treatment of hemophilia A.

Continuous infusion of intermediate-purity factor VIII in haemophilia A patients undergoing elective surgery

An open, non-randomized trial of continuous infusion therapy was conducted involving five patients with severe haemophilia A who required factor VIII (FVIII) prophylaxis for elective surgery. This was preceded by a 24-h preoperative pharmacokinetic study to characterize the pharmacokinetic parameters of each individual patient following a bolus dose of the intermediate-purity product. A retrospective matched control group was identified to allow for comparisons of FVIII usage between bolus and continuous infusion administration. A loading dose of FVIII was administered preoperatively, and the continuous infusion was started at the end of surgery and continued for 5 days. The patients' FVIII levels, vital signs, and infusion sites were monitored on a daily basis. The clearance was re-calculated on a daily basis using the FVIII activity of that day to adjust the infusion rate to achieve the desired FVIII level. The mean (CV%) pharmacokinetic parameters estimated preoperatively by noncompartmental analysis were: clearance 3.2 mL kg-1 h-1 (35.5%), volume of distribution 52.1 mL kg-1 (40.2%), mean residence time 17.4 h (23.3%), and half-life 12.7 h (23.6%). A progressive decrease in the clearance of FVIII from a mean of 3.1 mL kg-1 h-1 to 2.0 mL kg-1 h-1 (P = 0.125) over the first 5 days was observed. A therapeutically acceptable level of FVIII was systematically achieved, with the only complication being frequent thrombophlebitis. On average the patients used 19% less FVIII when compared with matched historical controls (P = 0.25). This method was found to be safe and effective in haemophilia A patients undergoing elective surgery procedures.

Pharmacokinetics, efficacy and safety of Humate-P in von Willebrand disease

In a pharmacokinetic study with Humate-P including six patients with various types of von Willebrand disease, a median half-life of 11.3 h for vWF:RCoF and of 15.2 h for vWF:Ag was found. The median value of in vivo recovery (IVR) was estimated for vWF:RCoF as 2.10 IU dL-1 plasma per 1 substituted IU kg-1 b.w. (or 73%), for vWF:Ag as 1.88 IU dL-1 plasma per 1 substituted IU kg-1 b.w. (or 69%); and for FVIII:C as 2.69 IU dL-1 plasma per 1 IU kg-1 b.w. (or 99%). Transient postinfusion shortening or normalization of previously prolonged bleeding time was observed in all patients. In a retrospective study involving 97 patients with various von Willebrand disease types, clinical efficacy and safety of treatment with Haemate-P in 73 surgical interventions, 344 separate bleeding events, 93 other events and 20 cycles of prophylactic treatment were evaluated. The clinical efficacy was rated good to excellent in 99% of the surgeries, in 97% of the bleeding episodes, in 86% of the other events, and in all prophylactic treatments. The overall tolerability was good. Adverse events possibly or probably associated with use of Humate-P/Haemate-P were rare, of non-serious nature and mild to moderate in their intensity.

A new cluster of hepatitis A infection in hemophiliacs traced to a contaminated plasma pool

Recently, several clusters of hepatitis A have been observed among hemophiliacs linked to factor VIII concentrates treated for virus inactivation solely with the solvent/detergent (S/D) method, a procedure that does not affect nonenveloped viruses such as the hepatitis A virus (HAV). A new outbreak of hepatitis A in six hemophiliacs treated with the same lot of a factor VIII preparation occurred recently in Germany. The objective of the study was to clarify whether these diseases were caused by the administration of the S/D-treated plasma product, rather than a community-acquired infection. Polymerase chain reactions designed to detect HAV nucleic acid have been carried out in the implicated factor VIII lots, in the corresponding plasma pools, and in serum samples of four out of six infected individuals. The nucleic acid sequences were determined in samples that resulted in positive amplification products. HAV sequences were found in one of the two plasma pools used for manufacture of the incriminated product, in the incriminated lot itself, and in all recipient sera tested so far, although the latter were collected up to 7 weeks after the onset of jaundice. The sequences obtained were completely identical, revealing a unique HAV strain of genotype IA. This study provides conclusive evidence that hepatitis A can be transmitted by factor VIII concentrates treated solely by the S/D procedure for virus inactivation. This inactivation method is not effective against nonenveloped viruses. Since a number of hepatitis A transmission episodes have been described with such preparations during the past 10 years, their continued use seems to be questionable unless additional virus removal or inactivation steps are introduced to prevent the transmission of nonenveloped viruses. Molecular approaches again proved to be reliable tools for elucidating the chain of virus transmission.

Continuous infusion of FVIII and FIX concentrates: in vitro analysis of clinically relevant parameters

A high purity factor VIII/von Willebrand Factor (FVIII/vWF) concentrate (IMMUNATE [STIM plus]) (n = 6 batches), and a high purity factor IX (FIX) concentrate (IMMUNINE [STIM plus]) (n = 7 batches), were assessed in vitro for their applicability to continuous infusion. Parameters pertinent to continuous infusion were investigated and included stability, sterility and, in the case of FIX, the generation of potentially thrombogenic components. Four stationary or transportable mini infusion pumps, equipped with polyethylene, polypropylene or polyvinylchloride plastic components were used. The concentrates were reconstituted without extra filling volume and perfused at 12.5 mL h-1 and 1 mL h-1; sampling was carried out at the start of the experiment and for up to 48 h. The FVIII procoagulant activity (FVIII:C) was assayed by amidolytic, 1-stage and 2-stage assays; vWF was examined for ristocetin cofactor activity, antigen and multimers. The FIX coagulation activity (FIX:C) was determined by a 1-stage coagulation assay; thrombogenicity potential was assessed in vivo (Wessler stasis model in rabbits) and in vitro (FIXa and nonactivated thromboplastin time). Reconstituted concentrate incubated under the same conditions served as a control. Both concentrates remained sterile throughout the testing period. The perfused and control samples remained stable, retaining over 95% of activity for FVIII:C and over 90% for FIX:C for up to 48 h. Intermittent decrease of FVIII:C or FIX:C was not observed, suggesting no adsorption of FVIII or FIX onto plastic surfaces during either short or long-term exposure. No thrombogenic components were detected in the high purity FIX concentrate. Thus, under the in vitro conditions used, FVIII/vWF and FIX were found to be suitable for administration by continuous infusion.

Prophylactic treatment in Sweden--overtreatment or optimal model?

At the haemophilia centre in Malmö, Sweden, regular prophylactic treatment is begun at 1-1 1/2 years of age, before the onset of joint bleeds. The dose and dose interval are optimised by means of pharmacokinetic studies to determine the individual patient's FVIII or IX metabolism, the goal of maintaining a level > 1% of normal being taken as a guideline which experience has shown to yield satisfactory control of bleeding diathesis. An optimal model for prophylactic treatment needs to be applicable to haemophiliacs and acceptable to health authorities in a majority of the countries in the world. To fulfill these criteria, the Swedish model, which has been shown to yield most satisfactory outcome, can hopefully be further refined in the future. Were continuous infusion, using a recombinate concentrate with a prolonged half-life, technically feasible and socially acceptable to the child, we would probably have attained the optimal model of prophylactic treatment.

Factor VIII inhibitors in mild and moderate-severity haemophilia A

Inhibitors are an uncommon complication of mild haemophilia, occurring in 3-13% of patients and usually arising during adulthood. The risk of inhibitor development in this group appears to be associated with relatively few high-risk factor VIII genotypes clustered in the A2 and C2 domains, especially the Arg593-Cys and the Trp2229-Cys mutations. Kindreds with these mutations have an inhibitor incidence of up to 40%. These mutations may induce a stable conformational change in the factor VIII molecule rendering it antigenically distinct from wild-type factor VIII. Inhibitors in mild haemophilia usually cross-react with endogenous factor VIII reducing the basal VIIIC to < 0.01 IU/ml, and causing spontaneous bleeding. This bleeding is sometimes severe and life-threatening, two-thirds of patients developing a pattern of soft tissue, gastrointestinal (GI) and urinogenital bleeding reminiscent of acquired haemophilia. Bleeding has been treated with human and porcine factor VIII, bypass therapy and DDAVP. Recombinant factor VIIa and DDAVP have the advantage that they do not induce an anamnestic rise in inhibitor titre. About 60% of these inhibitors disappear in the remainder over a median of 9 months. Few of these inhibitors recur, suggesting that most such patients have become tolerant. The inhibitors persist long-term and remain troublesome in about 40% of patients. The limited data available on immune tolerance induction in this group indicate a generally poor response to this approach. Two of nine achieved tolerance, with a partial response in a further four. Inhibitors are an uncommon but life-threatening complication of haemophilia. This complication should be considered when selecting the treatment modality for patients with a family history of inhibitors, and DDAVP used whenever possible.

The natural history of the immune response to exogenous factor VIII in severe haemophilia A

The development of inhibitory antibodies to factor VIII (fVIII) in severe haemophilia A patients is a serious therapeutic complication. Using a highly sensitive immunoprecipitation (IP) assay which measures all anti-fVIII antibodies, we have tested severe haemophilic plasmas from two clinical studies. Inhibitor titres in the range of 0.4 to 1 Bethesda units/ml (BU/ml) could not be verified by IP as being due to an immune response to fVIII in 35% of plasmas tested. Low fVIII recoveries were likewise correlated with the presence of antibodies in 29% of plasmas tested. However, 16% of plasmas without inhibitor titres had immune responses as measured by IP. The rapidity of antibody appearance did not allow their effective detection by IP before development of inhibitor titres. These results suggest that the IP assay can provide a valuable confirmation of anti-fVIII antibody production when the Bethesda assay is low or negative and where clinical observations suggest their presence, but they cannot be used reliably to detect early immune responses.

The genetic basis of inhibitor development in haemophilia A

Inhibitor development is now the main complication of replacement therapy in haemophilia A. Given that most severely affected patients make no detectable factor VIII, it is perhaps surprising that only approximately 30% actually mount an immune response to factor VIII as a foreign antigen. Those that do mostly have major factor VIII gene lesions. The association of HLA genotype with inhibitors in patients with identical mutations is weak. Environmental factors may be more important than genetic in antibody response to factor VIII.

Determination of adequate moisture content for efficient dry-heat viral inactivation in lyophilized factor VIII by loss on drying and by near infrared spectroscopy

A requirement for a minimal threshold level of moisture in order for efficient virus inactivation to occur during dry heat treatment of freeze-dried coagulation factor concentrates is described. Techniques used to determine moisture content during heating were Loss on Drying and Karl Fischer. The Loss on Drying was suspected to have occasional errors as a result of sample preparation being influenced by interference from atmospheric moisture. Therefore, a non-invasive, non-destructive method for determination of residual moisture content using near infrared spectrometry (NIR) was developed for freeze-dried antihaemophilic factor (AHF). Calibration equations were determined against Loss on Drying and Karl Fischer assay methods and these equations evaluated for the predictive efficiency. Both Loss on Drying and NIR were used to evaluate the effect of moisture content on the efficiency of virus inactivation by dry heat at 80 degrees C. A minimum level of moisture of greater than 0.7%, as determined by Loss on Drying, was necessary for a virus reduction in the magnitude of 4 log10 for hepatitis A virus, porcine parvovirus and pseudorabies virus.

Hepatitis A virus infections associated with clotting factor concentrate in the United States

BACKGROUND

Two cases of hepatitis A among persons exposed to the same lot of solvent/detergent-treated antihemophilic factor VIII concentrate were reported to a surveillance system. An investigation was conducted to find additional cases and determine the source of infection.

STUDY DESIGN AND METHODS

A seroprevalence study was conducted among persons with exposure to the suspect lot for serologic evidence of recent infection with hepatitis A virus (HAV).

RESULTS

Six cases of recent HAV infection were discovered: four of the patients had been infused with material from the suspect lot of factor VIII, and two had received infusions of factor IX concentrate made from plasma pools common to the suspect factor VIII lot. HAV was identified in one of the plasma pools, in the factor VIII product, and in serum or stool from two factor VIII recipients and one factor IX recipient. The genetics sequence of the virus in the plasma pool, the factor VIII lot, and the factor VIII recipients were identical, while that of the virus in the factor IX recipient differed by a single base.

CONCLUSION

These data document the transmission of HAV by a factor VIII concentrate and implicate factor IX products manufactured from a common source-plasma pool.

Hepatitis A virus sequence detected in clotting factor concentrates associated with disease transmission

Since the early 1990s hepatitis A virus (HAV) infections among recipients of solvent-detergent treated factor VIII concentrates have occurred in Europe, South Africa and the United States. A review of the epidemiological and laboratory-based investigations of the outbreaks in Germany and Ireland were consistent with transmission by factor concentrates but limited information about transmission based upon nucleic acid sequences was obtained, and no clear chain of transmission could be established. Within the United States, hepatitis A infections associated with solvent detergent concentrate occurred in a single patient in 1993, and a cluster of cases in 1995. Although the 1993 factor concentrate was positive for virus, samples from the patient were not available. The virus present in the cluster of 1995 factor VIII patients, the factor concentrate they received, and the original plasma pool was identical, while the virus identified in the factor IX patient differed by a single base.

[Acute posterior wall infarct after factor VIII concentrate administration to a patient with severe hemophilia A]

HISTORY AND CLINICAL FINDING

A 69-year-old man with severe haemophilia A sustained an acute myocardial infarction (MI) after self-administration of 3000 units factor VIII over 10 min. On admission he had no signs of heart failure.

INVESTIGATIONS

The ECG showed an acute posterior wall MI. Creatinekinase rose to a maximum of 321 U/l with a significant MB proportion. The echocardiogram demonstrated hypokinesia of the posterior wall.

TREATMENT AND COURSE

After initial thrombolysis treatment with a total of 100 mg rtPA according to an accelerated scheme coronary angiography, performed because the symptoms persisted, revealed two-vessel disease. A subtotal stenosis of the right coronary artery was balloon-dilated with good primary results. Regular factor VIII substitution was temporarily administered with the aim of initially achieving high normal levels of factor VIII activity.

CONCLUSION

Factor VIII substitution in haemophilia A may promote thrombotic complications. Thrombolytic treatment and balloon angioplasty of acute MI can be successfully performed even in patients with severe haemophilia A.