Obesity in haemophilia patients: effect on bleeding frequency,clotting factor concentrate usage,and haemostatic and fibrinolytic parameters

The prevalence of obesity in patients with haemophilia (PWH) is increasing. We investigated the effect of obesity on bleeding frequency and clotting factor concentrate (CFC) usage in PWH and assessed whether prothrombotic changes observed in obesity differ between controls and PWH. Number of bleeds and CFC usage were compared between obese (N = 51) and non‐obese (N = 46) haemophilia A patients. Markers of haemostasis and fibrinolysis were compared between PWH, and gender‐, age‐ and body mass index (BMI)‐matched non‐haemophilic controls (N = 91). Median number of bleeds/patient‐month was comparable between obese and non‐obese patients with severe haemophilia (P = 0.791). Obese patients with severe haemophilia used 1.4 times more CFC/patient‐month than non‐obese patients (P = 0.036). When adjusting for weight this difference disappeared (P = 0.451). von Willebrand factor plasma concentration (VWF:Ag), factor VIII activity and endogenous thrombin potential were higher in obese than in non‐obese controls. Obesity did not influence these markers in PWH. Plasminogen activator inhibitor type 1 levels were higher in obese vs. non‐obese PWH (P < 0.001), whereas levels were comparable between PWH and controls (P = 0.912). Plasmin‐α2‐antiplasmin complex (PAP) levels appeared to be lower in obese vs. non‐obese subjects, both within controls (P = 0.011) and PWH (P = 0.008). However, in PWH, PAP levels were higher than in controls (P < 0.001). Obesity is associated with an increase in net CFC usage in PWH, but has no effect on bleeding frequency. In addition, obesity attenuates hyperfibrinolysis in PWH. Future research investigating whether obese PWH need CFC treatment dosed on weight or whether a lower dosage would suffice to prevent and treat bleedings is needed.     

The use of intermediate-purity clotting factor concentrates and HIV disease progression in men with haemophilia

Summary. On the basis of evidence from the immune systems of patients with haemophilia infected with HIV, patients in the UK have been switched to high-purity clotting factor concentrates. However, there is very little information currently available on the effect of intermediate-purity clotting factor concentrates on progression of HIV disease. Among 99 HIV-positive men with severe factor VIII deficiency registered at The Royal Free Hospital Haemophilia Centre, a 100 IU kg^-1 increase in the yearly amount of concentrate received did not appear to be associated with more rapid progression to AIDS, death or to a low CD4 count. However, the use of total concentrate usage may mask a more subtle effect of specific concentrate contaminants on the progression of HIV disease.     

Comparing bleed frequency and factor concentrate use between haemophilia A and B patients

Summary. Haemorrhagic manifestations in patients with haemophilia A and B are considered quite similar for comparable level of factor deficiency. We investigated the bleeding frequency and factor usage between HA and HB patients with comparable disease severities. We collected data on frequency of bleeds and factor concentrate utilization over 3 years, from January 2001 to December 2003. Information was gathered from home infusion logs recorded by patients or their parents, and treatment records from the Hemophilia Clinic or the Hospital Emergency Department. Data were available on 58 patients with severe HA (FVIII < 0.01 U mL^?1), 10 with moderate HA (FVIII < 0.05 U mL^?1), 15 with severe HB, and five with moderate HB who required treatment for episodic bleeds, postoperative haemostasis and for primary or secondary prophylaxis. The HA patients bled more frequently than HB patients (14.4 vs. 8.63 bleeds/patient/year), but used similar amounts of concentrate per year. HA patients underwent surgical procedures 3.2 times more frequently than HB patients to correct musculoskeletal complications. A total of 21 363 409 IU of recombinant FVIII was used by patients with HA (104 722 IU/patient/year) and 6 430 960 IU of recombinant factor IX, by patients with HB (107 182 IU/patient/year). The difference in factor concentrate usage is not statistically significant (P > 0.05). The decrease in bleed frequency in haemophilia B indicates that the conclusions from randomized trials of prophylaxis in HA may not be accurately applied to HB.     

Viral safety of a pasteurized, monoclonal antibody-purified factor VIII concentrate in previously untreated haemophilia A patients

The efficacy and viral safety of a pasteurized, immunoaffinity-purified procoagulant factor VIII protein (FVIII:C; Monoclate-P) was studied in two multicentre, prospective, open-label trials in 30 previously untreated patients, 18 with severe (< 1% FVIII:C activity), and 12 with moderate (1% to 5% FVIII:C activity) haemophilia A. Clinical assessments, performed at screening and regularly thereafter for 6 to > 24 months (maximum 34 months), showed that none of 24 assessable patients acquired illnesses consistent with monitored transfusion-transmissible diseases. No patients acquired hepatitis B surface antigen, or antibodies against hepatitis B core antigen, hepatitis C, or human immunodeficiency virus. Likewise, no patients acquired treatment-related hepatitis A antibodies or sustained elevations of alanine aminotransferase levels. The safety profile for Monoclate-P is brought about by a multi-step safety system that incorporates viral inactivation (through a combination of immunoaffinity chromatography and pasteurization) plus donor screening, plasma testing, and quality assurance. The inhibitor development rate (13% low titre, 10% high titre) was similar to that reported in the literature for other FVIII concentrates (24% to 52%). The most frequently reported adverse events were related to typical infant and childhood diseases. Monoclate-P was effective in all patients treated according to protocol, except in two, who developed inhibitors.     

On-demand but not prophylactic treatment with FVIII concentrate increase thrombin activatable fibrinolysis inhibitor activation in severe haemophilia A patients

Introduction: Thrombin activatable fibrinolysis inhibitor (TAFI) down‐regulates fibrinolysis after activation by thrombin/thrombomodulin. We investigated the effect of treatment with FVIII concentrate on plasma levels of pro‐TAFI and activated TAFI in haemophilia A patients. Methods: Samples were collected pre and posttreatment from patients treated prophylactically or on‐demand. Pro‐TAFI, TAFI/TAFIi and FVIII levels were measured in all samples. Results: Treatment had no effect on pro‐TAFI levels. Pro‐TAFI was similar in both patient groups but higher than in controls. Patients from the prophylactic treatment group had measurable FVIII levels pretreatment while in the treatment‐on‐demand group FVIII levels were ≤0.01 IU/mL. In the prophylactic treatment group, the levels of TAFI/TAFIi were significantly lower pre‐ and posttreatment (4.31 ± 3.14 and 3.48 ± 2.65 ng/mL respectively) than in the on‐demand group (13.02 ± 3.47 and 14.87 ± 3.47 ng/mL respectively). This difference may be due to release of tissue factor at the injury site in the on‐demand group. This could induce thrombin and TAFI activation within the clot counterbalancing fibrinolysis in these patients. In the prophylactic group, no injury existed, thus there was insufficient thrombin generation within the clot to activate TAFI. Conclusion: These findings suggest that in patients to whom FVIII is administered on demand the fibrinolysis activity is more down regulated than in patients following a prophylactic treatment regime.     

Clinical assessment of Optivate®, a high‐purity concentrate of factor VIII with von Willebrand factor,in the management of patients with haemophilia A

Summary. Factor VIII (FVIII) concentrates have revolutionized the treatment of patients with haemophilia A. Concerns over the transmission of viral infections through these products have been addressed through stringent, donor‐screening procedures and robust antiviral manufacturing steps. Bio Products Laboratory has developed a high‐purity FVIII product with von Willebrand factor, Optivate^®. Its safety, tolerability and efficacy as prophylaxis and treatment of bleeds have been established in long‐term studies. Seventy previously treated patients with severe haemophilia A, with ≥20 exposure days, were recruited into two long‐term, multicentre, open‐label studies. The protocols were virtually identical. Patients received Optivate^® either prophylactically or on‐demand. A mean of 159.0 EDs were experienced over 11 320 infusions. Under both conditions, Optivate^® was well tolerated. Only 10% of patients experienced a treatment‐related adverse event; the most commonly reported were headache (4% of patients) and dizziness (3% of patients). The mean number of bleeds/patient over the 2 year treatment period was 23.5 during prophylactic use and 70.4 during on‐demand use. In patients treated prophylactically, clinical responses to breakthrough bleeds were rated by physicians as excellent or good and as very helpful or helpful by patients in 95% of bleeds. Clinical responses for on‐demand patients were rated as excellent or good by physicians and helpful or very helpful by the patients for 91% of bleeds. There were no viral transmissions or inhibitors. The studies confirm the clinical efficacy and safety of Optivate^® in both prophylactic and on‐demand management of patients with haemophilia A.     

The knowledge and perception of factor concentrate in persons with haemophilia A

Summary. Objectiues . To evaluate haemophilia patients' knowledge and understanding of factor concentrate products and to assess their feelings regarding purity and viral safety of these products.
Methods . Sixty questionnaires were distributed and completed by patients or parents of patients with severe/ moderate haemophilia A at two large comprehensive haemophilia centres in the USA and Italy.
Results . Most patients knew what brand of factor concentrate they used, but less than half were aware of how their concentrate was virally inactivated. The majority of responders perceived recombinant factor VlII as being the concentrate with the highest degree of purity. The majority felt the decision of which concentrate to use should be the care-givers not the patients.
Conclusions . It appears that patients need more education concerning the concentrate they are using, and its method of viral inactivation and purity.     

The impact of a very high-purity factor VIII concentrate on the immune system of HIV-infected haemophiliacs: a randomized, two-year comparison with a high-purity concentrate

Summary. Randomized and cohort studies have provided evidence confirming the hypothesis, based on in-vitro observations, that the use of very high-purity factor VIII (FVIII) concentrates, either immuoaffinity chromatography purified or produced by recombinant DNA technology, may slow immunological deterioration in human immunodeficiency virus (HIV)-infected haemophiliacs, while high-purity concentrates, produced by ion-exchange chromatography, did not produce a benefit. Even though these data clearly indicate that very high-purity concentrates should be preferred for the replacement therapy of HIV-positive haemophiliacs, there are little data, based on direct comparison, supporting the use of very high-purity concentrates rather than high-purity preparations, which are less expensive. In an attempt to address this issue, we prospectively compared CD4 cell counts and changes of clinical status in 18 HIV-positive haemophiliacs, randomly assigned either to receive the treatment with a very high-purity FVIII concentrate, purified by immunoaffinity chromatography, or a high-purity product, produced by ion-exchange chromatography. All patients had CD4 lymphocyte counts below 300 μL^-1, were negative for the hepatitis B surface antigen and the HIV p24 antigen, and were receiving antiretroviral treatment with Zidovudine for at least 6 months. There were no significant changes of CD4 cell counts over the 96-week follow-up period or between the two groups. No signficant differences between the two groups were detected in the occurrence of AIDS-defining diagnoses (one in each group). On the whole, no striking benefit is conferred to the immune status of asymptomatic HIV-positive haemophiliacs by using either of these high-purity and very high-purity FVIII concentrates for 96 weeks. Larger prospective randomized trials are needed to establish definitely whether it is necessary to resort to very high-purity concentrates or it is sufficient to use high-purity concentrates to slow the fall of CD4 cell counts that occurs in HIV-positive haemophiliacs. Randomized trials, based on clinical end-points, are also needed to demonstrate whether slowing the fall in CD4 cells results in clinical benefits, delaying the occurrence of AIDS.     

Transmission of symptomatic parvovirus B19 infection by clotting factor concentrate

The risk of acquiring diseases from transfusion of blood and blood products is well recognized and the issue of parvovirus in haemophiliacs is not a new one. We report two patients with haemophilia acquiring iatrogenic parvovirus B19 infection, resulting in life-threatening sepsis in one, an immunocompetent adult. Over the last 10 years there has been great progress in manufacturing safer products with regard to enveloped viruses such as HIV, hepatitis B and C. A recent outbreak across Europe of hepatitis A in haemophiliacs treated with plasma-derived factor VIII concentrates has made haemophilic treaters concerned about the known (parvovirus B19 and hepatitis A) and the unknown non-lipid enveloped viruses that may be contained in the clotting factor concentrates, because these are resistant to the existing viral inactivating techniques. The possibility of HIV itself mutating into a non-lipid enveloped virus emphasizes the need to seek and use safer products.     

Immune tolerance therapy utilizing factor VIII/von Willebrand factor concentrate in haemophilia A patients with high titre factor VIII inhibitors

Summary.  Factor VIII (FVIII) inhibitors remain a serious complication of treatment for patients with haemophilia A. Immune tolerance induction (ITI) can eliminate inhibitors in the majority of patients, but there are major concerns related with this therapy. Investigators have raised the possibility that the use of FVIII/von Willebrand factor (FVIII/VWF) concentrates may improve the success rate of ITI and may shorten the duration of therapy necessary to attain tolerance. This retrospective study describes 25 patients at five institutions in the USA, who were treated with FVIII/VWF concentrate as part of their ITI. These were all patients who were considered poor prognosis because of clinical and laboratory characteristics, which made ITI less likely to be successful or because of a poor response to initial ITI with a monoclonal/recombinant FVIII concentrate. Overall success (complete tolerization) was 32% with another 40% attaining partial tolerization, but not complete tolerization. Of those patients attaining only partial tolerization, two patients ultimately discontinued ITI and had return of their high titre inhibitors. Eight percent of patients failed to attain either partial or complete tolerization and discontinued ITI. Another 24% are continuing with ITI but have titres of >10 BU. This study adds further retrospective data to the information regarding the use of FVIII/VWF concentrate in ITI.     

Prevalence of IgG antibodies to human parvovirus B19 in haemophilia children treated with recombinant factor (F)VIII only or with at least one plasma-derived FVIII or FIX concentrate: results from the French haemophilia cohort

Human parvovirus B19 (B19) has been transmitted by some brands of virally attenuated plasma-derived factor VIII (FVIII) or IX (FIX) concentrates. To quantify the differences of human parvovirus B19 risk transmission between albumin-stabilized recombinant factor and plasma-derived factor, we studied the prevalence of IgG antibodies to B19 (anti-B19) in 193 haemophiliac children between 1 and 6-years of age who had previously been treated with albumin-stabilized recombinant FVIII only (n = 104), and in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates (n = 89). Association between the prevalence of anti-B19 and the treatment group was analysed using multivariate logistic regression. Age, severity and type of haemophilia, number of cumulative days of exposure to factor VIII or IX, previous history of red blood cells or plasma transfusion were considered as potential confounding variables. A higher prevalence of anti-B19 was found in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates than in children treated with albumin- stabilized recombinant FVIII only (OR: 22.3; CI: 7.9-62.8), independently of the other factors studied.     

A post-marketing safety and efficacy assessment of a monoclonal antibody purified high-purity factor VIII concentrate

Summary. The identification of infrequent side-effects of clotting factor concentrates, undetected by clinical trials, is facilitated by post-marketing surveillance. We present a post-marketing surveillance study in which 97 patients with haemophilia A, attending three haemophilia centres, were treated over a median follow-up period of 284 days (range 1–1074), and a total follow-up period of 30,080 days, with a pasteurized immunoaffinity purified factor VIII concentrate (Monoclate-P, Armour, Collegeville, USA). 5216 infusions, using 10,527,000 units of Monoclate-P, were carried out, mostly for routine haemarthroses or prophylaxis.
No new inhibitors were observed during the study. At the start of the study 60/97 were HIV seropositive, 67/97 HBs antibody positive, 12 HbsAb negative and the remainder HBsAb positive before the study period. 13/14 tested were HAV seropositive at the beginning of the study. One patient became HAV seropositive during the study period, an infection thought to be community acquired. No other seroconversions were observed. Only one mild transfusion reaction was observed. This study confirms the safety and efficacy of Monoclate-P. Post-marketing surveillance or nationally organized pharmaco-vigilance should be practiced more widely to enable identification of low-frequency side-effects of treatment.     

Induction of immune tolerance with recombinant factor VIII in haemophilia A patients with inhibitors

We report on 11 patients (nine unrelated and a brother pair) with severe haemophilia A and factor VIII (FVIII) inhibitor, in whom immune tolerance (IIT) was induced with recombinant FVIII (r-FVIII). Their age ranged from 11 months to 47 years. The number of exposure days (ED) at inhibitor detection varied from 11 to 130. Nine of the 11 patients were high responders [>10 Bethesda units (BU)] with peak inhibitor levels ranging from 10 to 566 BU. The other two were low responders with peak levels between 0.7 and 2 BU. Before inhibitor detection, the patients had been receiving products of various purities. The IIT regimens were very heterogeneous, and the treatment schedule varied from a short period with 50 IU kg^–1 every 2 days, followed by 100 IU kg^–1 every 2 days and then 220 IU kg^–1 daily. The outcome was considered successful when the inhibitor level fell to 0.6 BU or lower after IIT treatment. The outcome overall was successful in nine out of 11 patients (81.8%), with the nine successful cases comprising seven of the nine high responders (77.8%) and the two low responders. Definite failure of IIT was observed in one high responder after two different IIT regimens. A second high responder is still on IIT treatment. All patients in whom IIT was successful are currently receiving r-FVIII on demand or prophylactically at various dosages. Despite the variability of the patient characteristics and the IIT schedules, this study demonstrates that r-FVIII represents an effective alternative for the eradication of inhibitors through IIT.