Successful treatment of urgent bleeding in von Willebrand disease with factor VIII/VWF concentrate (Humate-P®): use of the ristocetin cofactor assay (VWF:RCo) to measure potency and to guide therapy

This prospective, open-label, non-randomized study evaluated the safety and efficacy of factor VIII (FVIII)/von Willebrand Factor (VWF) concentrate (Humate-P) using treatment regimens based on VWF:ristocetin cofactor (VWF:RCo) activity in patients with von Willebrand Disease (VWD) in (i) urgent bleeding episodes, or (ii) in patients undergoing urgent and necessary surgery. This article summarizes the results of treatment for the 33 patients with 53 urgent bleeding events. The median loading dose of FVIII/VWF concentrate was 67.0 international units per kilogram (IU kg(-1)) VWF:RCo (range 25.7-143.2 IU kg(-1)), and the median daily maintenance dose per infusion was 74.0 IU kg(-1) (range 16.4-182.9 IU kg(-1)) for a median duration of 2 days (range 1-34 days). The overall efficacy (achievement of haemostasis) of FVIII/VWF concentrate was rated as excellent/good for 98% of the urgent bleeding events. No unexpected treatment-related adverse events or serious drug-related adverse events (AEs) were observed. This study supports the safety and efficacy of Humate-P administered in doses calculated in VWF:RCo units for the treatment of urgent bleeding episodes in patients with VWD.     

Efficacy of factor VIII/von Willebrand factor concentrate Alphanate® in preventing excessive bleeding during surgery in subjects with von Willebrand disease

Summary.  The adequacy of perioperative haemostasis with a high-purity, plasma-derived factor VIII product containing von Willebrand factor was retrospectively evaluated in 39 patients with type 1, 2 or 3 von Willebrand disease who underwent 61 major or minor surgical or invasive procedures. Overall, 93.5% of the responses to treatment were rated as excellent or good by the physician investigators. These ratings were confirmed by an independent panel of physician referees.     

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.     

Clinical efficacy of highly purified, doubly virus-inactivated factor VIII/von Willebrand factor concentrate (Fanhdi®) in the treatment of von Willebrand disease: a retrospective clinical study

The goal of therapy in patients with von Willebrand disease (vWD) is to correct the dual defect of primary haemostasis and intrinsic coagulation reflected by low levels of von Willebrand factor (vWF) and factor VIII coagulant activity (FVIII:C). Factor VIII/von Willebrand factor (FVIII/vWF) concentrates are currently the treatment of choice in vWD patients unresponsive to desmopressin (DDAVP). However, only few studies on their clinical use are available so far. The main objective of this study was to retrospectively evaluate the clinical efficacy of a highly purified, doubly virus-inactivated FVIII/vWF concentrate with a high content of FVIII/vWF (Fanhdi). Twenty-two patients with congenital vWD have been treated from 1999 to 2001 at eight specialized centres belonging to the Italian Association of Hemophilia Centers (AICE). Ten males and 12 females, median age 28.5 years, range 5-70 years) had type 3 vWD (six cases), DDAVP-unresponsive type 1 (nine cases) and type 2B (seven cases). The study drug was given to stop or prevent 12 bleeding episodes or to prevent excessive bleeding during 14 surgical or invasive procedures. Overall, replacement therapy with the concentrate showed an excellent to good clinical efficacy in 92% of bleeding episodes and in 93% of surgical procedures. No adverse events occurred during 1,601 infusions, accounting for a total of 304,500 IU of FVIII:C administered. These results confirm the efficacy and safety of this concentrate in the management of bleeding episodes and in the prevention of excessive bleeding during major and minor surgery.     

Treatment and prevention of acute bleedings in von Willebrand disease – efficacy and safety of Wilate®, a new generation von Willebrand factor/factor VIII concentrate

Summary.  For many patients with von Willebrand disease (VWD), the replacement therapy with von Willebrand factor (VWF)/factor VIII (FVIII) concentrates is the treatment of choice. To evaluate clinical efficacy, safety and tolerability of Wilate^®, an albumin-free VWF/FVIII concentrate with a ratio of the two haemostatic moieties of approximately 1 to 1, a prospective clinical programme has been designed. The dataset on the treatment and prevention of bleedings is derived from 44 patients (20 males and 24 females) of all VWD types. Thousand and ninety five bleeding episodes were treated with an overall efficacy rating of excellent or good in 96%. The median dose per treatment day was 26 IU FVIII:C per kg. Eighty-one per cent of bleeds were stopped within 1 or 2 days. Gastrointestinal (GI) bleeds needed higher doses (mean 44 IU kg⁻¹) and longer treatment (mean 4 days). Efficacy and dosing data from eight children of 12 or less years of age did not differ significantly from the overall study population. Nineteen patients, including six children, were treated prophylactically for more than 3 months (mean 14.8, range 3–46) with a mean prophylactic dose of 27.4 IU kg⁻¹ and a mean frequency of 1.9 infusions per week. A drop of bleeding frequency from a mean of 4.5 to 1.4 bleeds per month was observed. The overall tolerability was very good. Adverse drug reactions were rare and were mild or moderate in their intensity. The large prospective clinical dataset shows that Wilate^® is efficacious and safe in the treatment and prevention of haemorrhages in all VWD types in both adult and paediatric patients.     

Evaluation of a rapid von Willebrand Factor Activity Latex Immuno Assay for monitoring of patients with von Willebrand disease (VWD) receiving DDAVP® or VWF replacement therapy

Haemostatic management of surgery in patients with von Willebrand disease (VWD) includes DDAVP^® or von Willebrand factor (VWF)‐containing concentrates. Although the recommendations are for monitoring by VWF activity assays, it is quite common for clinicians to use factor VIII due usually to longer turnaround times required for VWF ristocetin cofactor assay (VWF:RCo) measurements. The aim of this study was to evaluate use of the rapid HaemosIL^? VWF activity (VWF:Act) latex immuno assay (LIA) on an automated coagulometer (ACL TOP^? 700; Instrumentation Laboratory, Bedford, MA, USA) compared to platelet‐based VWF:RCo assays in this setting. One hundred and sixty‐seven plasma samples from 42 patients [Type 1 (n = 22), Type 2A (n = 2), Type 2B (n = 3), Type 2M (n = 10), Type 3 (n = 3)] and acquired von Willebrand syndrome (n = 2) with VWD treated with DDAVP^® or VWF‐containing concentrates were included in the study. Method comparison and method bias were evaluated by Bland–Altman analysis (BA) and Passing and Bablok regression modelling respectively. BA of baseline samples (n = 39) showed a mean difference of ?3.0 (±1.96 SD ?25.2 to +19.4). Post (treatment) samples (n = 120) were separated into two groups. Group 1 contained samples with VWF:RCo levels 10 to ≤175 IU dL^?1 (n = 97) and group 2, samples with VWF:RCo levels >175 IU dL^?1 (n = 23). BA of group 1 postsamples showed a mean difference of +3.4 (±1.96 SD ?44.6 to +51.5), and the BA of Group 2 samples was ?23.9 (±1.96 SD ?136.1 to +88.3). In conclusion, use of HaemosIL VWF:Act LIA test on an automated coagulometer is a reproducible and rapid assay that can be used as an alternative test for monitoring VWF replacement therapy, facilitating dose adjustments on a real‐time basis.     

Efficacy and safety of a high purity, double virus inactivated factor VIII/von Willebrand factor concentrate (Biostate®) in patients with von Willebrand disorder requiring invasive or surgical procedures

Biostate is a double virally inactivated, plasma derived coagulation factor VIII (FVIII)/von Willebrand factor (VWF) concentrate registered and used in Australia, New Zealand and Asia for the treatment of patients with haemophilia A. Although Biostate has been well characterized for FVIII and VWF (ratio 1:2 respectively) and shows a similar VWF multimeric pattern to normal plasma, limited published data is available on its clinical efficacy and safety in patients with von Willebrand disorder (VWD) who require surgical procedures. We retrospectively assessed the efficacy and safety of Biostate in all VWD patients treated at three Australian haemophilia treatment centres undergoing invasive procedures or surgery over a 29-month period between April 2003 and September 2005. A chart review of 43 VWD patients (26 VWD type 1, 12 VWD type 2, 5 VWD type 3; 21 male, 22 female; mean age 52 years, range 19-80 years) undergoing 58 surgical procedures (24 major, 34 minor) was performed. For each procedure, data were collected on Biostate dosage and administration, adverse reactions, haemostatic efficacy and bleeding events. Haemostatic efficacy of Biostate was assessed as excellent in 78% or good in 22% of procedures. There were no bleeding events attributable to lack of efficacy in any patients. No adverse reactions related to the administration of Biostate were observed. These results suggest that Biostate is both safe and efficacious for the prevention of excessive bleeding in VWD patients undergoing surgery or invasive procedures.     

Screening for von Willebrand disease: contribution of an automated assay for von Willebrand factor activity

Measuring von Willebrand factor (VWF) activity is essential to the diagnosis of von Willebrand disease (VWD). The VWF activity is usually assessed based on measurement of the ristocetin cofactor (VWF:RCo). However, that test is technically challenging and has high intra- and inter-assay variabilities. The HemosIL VWF activity (VWF:AC) is a fully automated assay, recently proposed as a good alternative to VWF:RCo for VWD diagnosis. This study was undertaken to assess this new method. First, the analytical performance of VWF:AC on an automated coagulo-meter (ACLTop) was determined, and then this new method was compared with VWF:RCo and the platelet function analyzer (PFA100) for 160 patients referred for VWD screening. The VWF:AC achieved acceptable precision with within-run and between-run coefficients of variation ranging from 2.3% to 14.1%, and linearity from 10% to 100%. Despite some marked differences between VWF:AC and VWF:RCo for 10 plasmas tested, their agreement for VWD diagnosis was good. The VWF:AC had sensitivity similar to that of PFA100 (close to 100%), but better specificity (97.7% vs. 66% or 60%, depending on the cartridge used). The good analytical performance, and the sensitivity and specificity of VWF:AC to detect VWF deficiency renders it a suitable method for VWD screening. Our findings support VWF:AC use for the diagnostic work-up of VWD, paying close attention to concomitant clinical signs and bleeding score, as recommended for VWD.     

Optimizing therapy with factor VIII/von Willebrand factor concentrates in von Willebrand disease

In von Willebrand disease, the main goals of treatment are to correct the dual defect of haemostasis caused by a reduced or abnormal von Willebrand factor (vWF), i.e. the prolonged bleeding time (BT) and the deficiency of factor VIII coagulant activity (FVIII:C). The synthetic vasopressin analogue, desmopressin (DDAVP), has reduced the need for transfusions in most of the mild forms of von Willebrand disease but DDAVP is ineffective in type 3 and in other severe cases of types 1 and 2 von Willebrand disease. For many years cryoprecipitate has been the mainstay of replacement therapy but, after the introduction of virucidal methods, concentrates containing FVIII/vWF have been considered much safer than cryoprecipitate and proposed in von Willebrand disease management. FVIII/vWF concentrates have been produced and tested by many authors but there is only one report describing four virus-inactivated FVIII/vWF concentrates evaluated in a cross-over randomized trial. According to these in vitro and pharmacokinetic data, the following information can be derived: (a) no FVIII/vWF concentrate had an intact multimeric structure similar to that of normal plasma or of cryoprecipitate; (b) all FVIII/vWF concentrates were equally effective in attaining normal and sustained levels of FVIII:C postinfusion, although peak levels were more delayed in the concentrate devoid of FVIII:C; (c) no FVIII/vWF concentrate consistently normalized the BT in a sustained fashion. On the other hand, clinical haemostasis can be achieved in the management of bleeding episodes and of surgery for most of von Willebrand disease cases regardless of whether the BT is corrected; in the few rare cases with mucosal bleeding not controlled by FVIII/vWF concentrates, infusion of DDAVP or platelet concentrates can be administered in addition.     

Use of ristocetin cofactor activity in the management of von Willebrand disease

von Willebrand disease (vWD), the most common of the hereditary bleeding disorders, arises from quantitative or qualitative defects in von Willebrand factor (vWF). vWF is a multimeric plasma protein that plays a key role in primary and secondary haemostasis. In the current classification scheme, vWD is divided into six subtypes that are based on the nature of the vWF defect. Therapeutic strategies depend on the accurate identification of these subtypes. In most clinical situations, desmopressin is effective treatment for the great majority of patients with mild (type 1) disease, while replacement therapy with factor VIII/vWF concentrates that contain high levels of vWF activity is required for most type 2 and nearly all type 3 vWD patients. Several factor VIII/vWF replacement products are available, one of which (Humate P) has been approved for the treatment of vWD by the US Food and Drug Administration. Preliminary results of recent studies support the hypothesis that treatment with factor VIII/vWF concentrates based upon the content of vWF activity as reflected in the ristocetin cofactor assay is practicable, safe and efficacious. The establishment of optimal treatment regimens with respect to dose intensity and duration will require further study.     

Successful surgical haemostasis in patients with von Willebrand disease with Koate®DVI

Summary. This report describes our experience with Koate^®DVI, a factor VIII (FVIII) concentrate containing von Willebrand factor (VWF) for surgery in patients with von Willebrand’s disease (VWD). Twenty‐one patients underwent 26 procedures, 10 of which were major and 16 were minor. The median age was 27 years (3–55) and the mean weight was 52 kg (16–88). Among the ten patients (type 2–5; type 3–5) who underwent major procedures, the pre‐operative dose was 35 IU kg^?1 of FVIII followed by 10–20 IU kg^?1 once daily depending on FVIII:C levels. The mean total dose of FVIII used per procedures was 106 IU kg^?1 (30–190) over a mean duration of 7 days (3–11). In this group, pre‐infusion FVIII:C, VWF:Ag and VWF: ristocetin cofactor (RCoF) level that were 19.5% (1–64), 20 U dL^?1 (0–96) and 12% (0–66) increased to 72% (54–198), 131 U dL^?1 (68–206) and 68% (27–108) postinfusion, respectively. Sixteen minor procedures were performed in 11 patients (type 1–3, type 2–6, type 3–2). The preparative dose of FVIII was 10–20 IU kg^?1. The average duration of factor support was 2 days (1–3) for a mean total dose of 23 IU kg^?1 (9–60). The pre‐infusion levels of FVIII:C, VWF:Ag and VWF:ristocetin cofactor (RCo) which were 31% (22–64), 25.5 U dL^?1 (0–63) and 21% (0–76), respectively, increased to 76% (27–111), 73 U dL^?1 (30–137) and 45% (2–106) postinfusion. Whereas surgical haemostasis was achieved in all patients, minor postoperative bleeding occurred after one procedure in each group. Both were controlled with additional doses of factor replacement. We conclude that Koate^®DVI in modest doses provide adequate haemostasis for surgery in patients with VWD.     

Bleeding symptoms and laboratory correlation in patients with severe von Willebrand disease

Summary.  Type 3 von Willebrand disease (VWD) is a rare bleeding disorder with markedly decreased or absent von Willebrand factor (VWF) protein, accompanied by a parallel decrease in VWF function and factor VIII (FVIII) activity. The goal of this study was to describe the population of patients enrolled in the USA Centers for Disease Control Universal Data Collection (UDC) study with type 3 VWD, defined as a VWF:Ag of <10%, and to correlate bleeding symptoms with VWF and FVIII levels. Data on 150 patients were analysed. Almost all patients experienced bleeding episodes (98%) and required blood and/or factor product treatment (92%). While oral mucosal bleeding (the site of first bleed in 54%) was most common, subsequent muscle and joint bleeds were also seen (28%, 45%, respectively), and intracranial haemorrhage occurred in 8% of individuals. Mean age of first bleed was lower in those with either a FVIII ≤5% or a VWF:Ag <1%. Univariate marginal model analysis showed lower levels of FVIII and VWF:Ag both predicted a higher risk of joint bleeding. Longitudinal multivariate analysis found a lower FVIII level ( P  = 0.03), increasing age ( P  < 0.0001), history of joint bleeding ( P  = 0.001), higher body mass index (BMI) ( P  < 0.0001), and use of home infusion ( P  = 0.02) were all negatively associated with joint mobility. Low levels of VWF:Ag ( P  = 0.003) and male sex ( P  = 0.007) were also negatively associated with joint function. This study documents the strong bleeding phenotype in severe VWD and provides data to help target therapy, including prophylaxis, for patients most at risk of bleeding complications.     

von Willebrand factor/factor VIII concentrate (Humate‐P) for management of elective surgery in adults and children with von Willebrand disease

Summary. von Willebrand disease (VWD) is the most common inherited bleeding disorder. Treatment guidelines recommend the use of von Willebrand factor/factor VIII (VWF/FVIII) concentrate for VWD patients with type 2 or 3 VWD undergoing surgery, and type 1 patients undergoing surgery who are unresponsive, or for whom desmopressin acetate is contraindicated. This prospective, open‐label, multinational study evaluated the safety, efficacy and optimal dosing of a VWF/FVIII concentrate (Humate‐P) in subjects with VWD undergoing elective surgery. Dosing was based on VWF ristocetin cofactor (VWF:RCo) and FVIII pharmacokinetic assessments performed before surgery. Pharmacokinetic assessments were completed in 33 adults and 9 children. Haemostatic efficacy was assessed on a 4‐point scale (excellent, good, moderate/poor or none). Overall effective haemostasis was achieved in 32/35 subjects. Median terminal VWF:RCo half‐life was 11.7 h, and median incremental in vivo recovery was 2.4 IU dL^?1 per IU kg^?1 infused. Major haemorrhage occurred after surgery in 3/35 cases despite achieving target VWF and FVIII levels. Median VWF/FVIII concentrate loading doses ranged from 42.6 IU VWF:RCo kg^?1 (oral surgery) to 61.2 IU VWF:RCo kg^?1 (major surgery), with a median of 10 (range, 2–55) doses administered per subject. Adverse events considered possibly treatment‐related (n = 6) were generally mild and of short duration. The results indicate that this VWF/FVIII concentrate is safe and effective in the prevention of excessive bleeding during and after surgery in individuals with VWD.     

Postpartum von Willebrand factor levels in women with and without von Willebrand disease and implications for prophylaxis

The aim of this study was to elucidate the fall in von Willebrand factor (VWF) and factor VIII activity (FVIII) after childbirth in women with and without von Willebrand disease (VWD). VWF:RCo, VWF:Ag, and FVIII were obtained in the third trimester of pregnancy, on admission for childbirth, and 10 times postpartum. Specimens were processed within 4 h and analysed centrally. Means were calculated at each time point. Forty women (40 pregnancies) without VWD and 32 women (35 pregnancies) with VWD were enrolled. 15/32 with VWD were treated (30% of those with type 1 and all of those with type 2) in 17 pregnancies. Treatments prior to delivery consisted of desmopressin (2/17), VWF concentrate (15/17) and after delivery VWF concentrate (16/17). Duration of treatment was 0–21 days (median 6). VWF levels peaked at 250% of baseline – 4 h postpartum in women with VWD and 12 h postpartum in women without VWD. Thereafter, VWF levels fell rapidly, approached baseline at 1 week and reached baseline at 3 weeks. Except immediately postpartum, when the levels among treated cases were higher, levels among women with VWD appeared to parallel, but were lower than those among women without VWD. Levels were lowest among those who received treatment. VWF levels fall rapidly after childbirth. Except immediately postpartum, current treatment strategies do not raise VWF levels to the levels of women without VWD or even to the levels of women with milder, untreated VWD. Consequently, women with VWD may be at risk of postpartum haemorrhage despite treatment.     

Haemostatic treatment in connection with surgery in patients with von Willebrand disease

Haemostatic treatment in patients with von Willebrand disease (vWD) in connection with surgery aims at normalizing the haemostatic defect in order to avoid bleeding complications. Factor VIII (FVIII) levels in plasma must be normalized in connection with major surgery, whereas the bleeding time is more important for mucous membrane bleedings. Most patients respond well to treatment with desmopressin which stimulates the endogenous release of FVIII and von Willebrand factor (vWF) and shortens the bleeding time. Non-responders to desmopressin are substituted with a plasma-derived factor concentrate which contains vWF and FVIII. This paper includes a summary of retrospective data from the last 10 years on haemostatic treatment in connection with surgery from four haemophilia centres in Sweden and Denmark on 40 invasive procedures in 27 vWD patients and on one normal delivery. If a FVIII-containing concentrate is given prior to surgery a dose of 30–40 IU VIII:C kg⁻¹ will normalize FVIII levels in most severe cases. If a pure vWF concentrate is used, a dose of 40–50 IU RCoF kg⁻¹ will normalize RCoF in most cases, but FVIII levels will not be normalized until after about 12 h or later. Repeated doses of FVIII-vWF concentrate may lead to very high levels of FVIII in plasma because of the combined effect of the exogenous FVIII-substitution and the endogenous FVIII-release induces by the infused vWF. Dosage should be adjusted according to FVIII levels in plasma.