A retrospective study to describe the incidence of moderate to severe allergic reactions to factor IX in subjects with haemophilia B

Summary. Using a patient chart review process, we conducted a retrospective study to describe the frequency of allergic reactions in individuals with haemophilia B receiving factor IX (FIX) replacement therapy. The number of allergic reactions in individuals receiving a recombinant FIX (rFIX) product (Bene Fix ^®) was then compared with the number of reactions in patients receiving plasma‐derived FIX (pdFIX) products. Of the 180 subjects in the study, 163 received rFIX, 88 received pdFIX; 71 received both product types. A total of seven (3.89%) subjects had a moderate or severe allergic reaction to a FIX product (95% confidence interval [CI], 1.06–6.71%). Among those receiving rFIX, four subjects (2.45%) had an allergic reaction (95% CI, 0.08–4.83%). Of individuals taking pdFIX products, three (3.41%) developed an allergic reaction (95% CI, 0–7.20%). It was noted that three (1.84%) of those taking rFIX developed an inhibitor to FIX (95% CI, 0–3.90%), while four (4.55%) of those receiving a pdFIX product developed an inhibitor (95% CI, 0.19–8.90%). Inhibitor development was frequently associated with allergic reaction. These results provide evidence that there is no difference in the frequency of allergic reactions or inhibitor development in individuals receiving rFIX compared with those receiving pdFIX concentrates. The current study and a previous study of similar design have now compared the rate of allergic reactions associated with rFIX and pdFIX concentrates has now been compared in a total of 414 subjects; this represents the largest collection of data to date on this rare complication of haemophilia B therapy.     

A commentary on the differences in pharmacokinetics between recombinant and plasma‐derived factor IX and their implications for dosing

Summary. This commentary aims to summarize all aspects of the difference in pharmacokinetics (PK) between recombinant factor IX (rFIX) and plasma‐derived factor IX (pdFIX) and their implications for dosing. PK data were compiled from 17 published studies. The average clearance (CL) of rFIX normally ranged between 7.5 and 9.1 mL h^?1 kg^?1, whereas that of pdFIX was 3.8–5.4 mL h^?1 kg^?1. The average terminal half‐life was 18–24 h among all 72‐h studies on rFIX, in contrast to (normally) 29–43 h for pdFIX. In vivo recovery was more variable. Judging from the pooled data, the typical recovery of rFIX is around two‐third that of pdFIX. The difference in PK between rFIX and pdFIX is thus clear‐cut and has implications for dosing. As estimated from the compiled data, the dose required to reach any peak level of FIX immediately after administration would be 1.5 times higher for rFIX than for pdFIX, most probably with considerable individual variation. Calculated doses for a patient on a twice weekly prophylactic treatment to achieve a predetermined trough FIX level depended markedly on CL and were about twice as high with rFIX as with pdFIX. In summary, conversion factors between rFIX and pdFIX of 1.5 for single doses and 2 for prophylactic dosing can tentatively be applied; however, the interindividual variance both in recovery and CL of rFIX and pdFIX and the unknown variance in ratios between these PK parameters call for careful monitoring if a switch of treatment is made.     

Recombinant factor IX: discrepancies between one‐stage clotting and chromogenic assays

New and modified recombinant factor IX (rFIX) products are in development and accurate potency estimation is important to ensure the consistency of production and efficacy of these therapeutics. Collaborative study data obtained during the replacement of the 3rd International Standard (IS) for FIX concentrate suggested that there was a discrepancy between potency estimates for rFIX using clotting and chromogenic methods, when the rFIX candidate was measured against the plasma‐derived FIX (pdFIX) IS. This study explores potential chromogenic and one‐stage clotting method discrepancies in more detail. Five batches each of rFIX and pdFIX were assayed against the 4th IS FIX concentrate (a pdFIX) by activated partial thromboplastin time (APTT) one‐stage clotting assay and specific functional chromogenic assay. The potency of rFIX by chromogenic assay was consistently around 70% of the one‐stage clotting potency (average 78 and 108 IU mL^?1 respectively). These differences were not observed with pdFIX, which had similar potencies (average 96 IU mL^?1) by each assay method. In addition, different APTT reagents yielded different potency estimates for rFIX when assayed against the pdFIX IS, with a variation of up to 23%. In all cases, the differences were largely resolved when a rFIX reference was used as the standard. This study highlights some of the challenges associated with assay of rFIX products in the laboratory and that careful consideration needs to be given to the choice of reference material used. This is especially important with the imminent arrival of new and modified rFIX products.     

Safe switching from a pdFIX (Immunine®) to a rFIX (Bax326)

The ability to switch between coagulation factors safely is of common interest to haemophilia patients and treating physicians. This is the first formal prospective comparative evaluation of safety, efficacy and incremental recovery of a plasma‐derived FIX (pdFIX) and a recombinant FIX (rFIX) in the same haemophilia B patients following a switch from pdFIX Immunine^® to a recently developed rFIX Bax326 product. Patients (aged <65 years) who completed a pretreatment study which prospectively documented the exposure to Immunine^® and monitored FIX inhibitors while receiving prophylactic treatment were transitioned into pivotal (patients aged 12–65 years) and paediatric (patients aged <12 years) clinical studies investigating prophylaxis and treatment of bleeding episodes with Bax326. None of the 44 patients developed inhibitory or specific binding anti‐FIX antibodies during the course of the studies. A total of 38 unrelated adverse events (AEs) were occurred in 20/44 (45.5%) subjects during the Immunine^® study. Following a switch to Bax326, 51 AEs were reported in 25/44 (56.8%) subjects. The incidence of AEs related to Bax326 treatment (two episodes of dysgeusia in one patient) was low (2.3%); there were no serious adverse reactions. The comparison between Immunine^® and Bax326 demonstrated analogous haemostatic characteristics and annualized bleeding rates. Overall, there is direct evidence indicating a safe and clinically effective transition from a pdFIX (Immunine^®) to a newly developed rFIX (Bax326¹) for prophylaxis and treatment of bleeding in previously treated patients of all age cohorts with severe or moderately severe haemophilia B.     

Recombinant human factor IX: replacement therapy, prophylaxis, and pharmacokinetics in canine hemophilia B

Recombinant human factor IX (rFIX) has been expressed in transduced cultured cell systems since 1985. Because there has been limited in vivo testing of rFIX in hemophilia B subjects, this study was undertaken using the severe hemophilia B canines of the Chapel Hill strain. Three groups of hemophilic dogs received either 50, 100, or 200 IU/kg of rFIX. As a control, a fourth group of hemophilic dogs received 50 IU/kg of a high purity, plasma-derived human FIX (pdFIX). The coagulant and hemostatic effects of rFIX and pdFIX were similar with all comparative dosing regimens. Based on activity data, the elimination half-life of rFIX was 18.9 +/- 2.3 hours and pdFIX was 17.9 +/- 2.1 hours. A prophylactic regimen administering rFIX daily resulted in a continuous therapeutic level of plasma FIX and was accompanied by a two-fold increase in recovery levels by day 5, compared to that observed with administration of a single bolus. The mechanisms of the high to complete recovery of FIX with the prophylactic regimen could depend not only on the degree of saturation of the vascular endothelial binding sites but also on the altered dynamics of the balance of FIX distribution between the intravascular and extravascular compartments. The pharmacokinetic (PK) parameters for rFIX and pdFIX were similar. However, the relative PK values for V1 and V5s of both products on day 5 differed greatly from day 1 and may reflect the changing equilibrium of FIX between compartments with elevated levels of plasma FIX. Neutralizing antihuman FIX antibodies resulting from human FIX antigen being administered to FIX deficient dogs were observed beginning at 14 days. The antigenicity of rFIX and pdFIX appeared to be comparable. Despite the very different procedures used for production of rFIX and pdFIX products, in vivo testing in hemophilia B dogs showed the functional behavior of these products is similar; they are highly effective for replacement therapy and for prophylaxis.     

Differential investigations from plasma‐derived and recombinant Factor IX revealed major differences in post‐translational modifications of activation peptides

Post‐translational modifications (PTMs) located on the activation peptide (AP) of recombinant FIX (rFIX, BeneFIX^®) and plasma‐derived FIX (pdFIX, Betafact^®) have been investigated by mass spectrometry to review the structural differences between these two products. Three major structural differences were pointed out. rFIX contains a low amount of phosphorylated and sulphated AP (4% for rFIX vs. 70% for pdFIX); rFIX N‐glycans are only sialylated in the α2‐3 linkage, whereas pdFIX N‐glycans contain both type of α2‐3 and α2‐6 linkages, and rFIX does not contain any sialyl Lewis^X glycoantigens contrary to pdFIX. These variations might participate in the in vivo potential different behaviours of the two molecules.     

A clinical study assessing the pharmacokinetics,efficacy and safety of AlphaNine®, a high‐purity factor IX concentrate,in patients with severe haemophilia B

Summary. Effective treatment with factor IX (FIX) requires a thorough consideration of the properties of the concentrate to be used as replacement therapy, to date, the only available treatment for haemophilia B. The aim of the study was to determine the pharmacokinetics, clinical efficacy and safety in routine clinical use of AlphaNine^®, a high‐purity human FIX concentrate. This open, single‐arm, multicentre, non‐randomized trial included 25 subjects (age ≥ 12) with moderate/severe haemophilia B. Pharmacokinetics was assessed at baseline and after a 6‐month follow‐up. The degree of haemostasis control achieved was evaluated during a 12‐month follow‐up. Safety was evaluated in terms of tolerance, thrombogenicity, immunogenicity and viral safety. Mean recovery was 1.01 ± 0.19 IU dL^?1 per IU kg^?1 at baseline and 1.23 ± 0.34 IU dL^?1 per IU kg^?1 6 months later. Terminal half‐life was 34.5 ± 6.2 h and 33.7 ± 5.4 h, respectively. Ratios of each parameter between the two pharmacokinetic studies were all close to 1. A total of 1,576,890 IU AlphaNine^® were administered in 889 infusions (mean dose per infusion: 1774 IU; 3.2 infusions per month per patient). The main reasons for infusion were mild/moderate bleeding (62.3%) and prophylaxis (20.5% continuous, 15.6% intermittent). Overall, 93.0% of the efficacy assessments were rated as excellent/good and 88.8% of bleedings resolved after the first infusion. Twenty‐one adverse events were reported in eight patients, none of which was considered related to the study medication. AlphaNine^® showed a pharmacokinetic profile in agreement with that of other plasma‐derived FIX concentrates and provides safe and clinically effective substitution therapy for patients with haemophilia B.     

Clinical efficacy,safety and pharmacokinetic properties of the plasma‐derived factor IX concentrate Haemonine® in previously treated patients with severe haemophilia B

Summary. Plasma‐derived factor IX (FIX) concentrate remains an important choice for replacement therapy in haemophilia B patients. Haemonine ^® is a high purity double‐virus inactivated human plasma‐derived coagulation FIX concentrate (pdFIX). Aim was to evaluate the clinical efficacy, safety and pharmacokinetic properties of Haemonine in three prospective, open‐label uncontrolled studies and a compassionate use program in previously treated patients with severe haemophilia B. Long‐term efficacy and safety were investigated in 29 patients treated prophylactically and, in addition, treatment on‐demand (TOD) in the case of acute haemorrhage. Pharmacokinetic properties were assessed in 14 patients at baseline and after 3 months of regular treatment. Pharmacokinetic parameters were in accordance with published data and remained nearly unchanged over time, notably recovery and half‐life. Mean terminal elimination half‐life was 27.6 h and 25.0 h, mean incremental recovery (IU dL^?1/IU kg^?1) was 1.55 and 1.60, at baseline and 3 months, respectively. Haemonine was shown to be effective in preventing and controlling bleeds. 55.2% (16/29) of patients were free of bleeds under prophylaxis. 38 haemorrhages occurred, 42% (16/38) required treatment and 87.5% (14/16) resolved after a single infusion, 12.5% after 2 infusions. All responses reported on haemorrhages were rated as ‘excellent’ or ‘good’. Moreover, ‘excellent’ haemostatic efficacy was demonstrated in 12 surgeries with no complications. Few adverse events (AEs) and no thrombogenic complication, nor induction of FIX inhibitory antibodies were observed. Haemonine is effective, safe and well tolerated in long‐term prophylaxis, TOD and when applied after minor and major surgeries.     

Pharmacokinetic study of a high-purity factor IX concentrate (Factor IX Grifols®) with a 6-month follow up in previously treated patients with severe haemophilia B

Summary. Optimal replacement treatment in haemophilia B patients requires a good understanding of the pharmacokinetics of factor IX (FIX). The aim of this study was to compare the pharmacokinetic profile of Factor IX Grífols^®, a highly purified human FIX concentrate with two specific pathogen inactivation/removal steps, to that of available FIX preparations. The study was an open, non‐randomized trial including 25 male subjects older than 12 years of age with severe haemophilia B. Pharmacokinetic profile of the FIX preparation regularly used by the subjects was determined as control. Pharmacokinetic profile of Factor IX Grifols^® was determined twice, one 7–15 days after control assessment and second after a 6 months period had elapsed. Results showed that all products had peak plasma levels of FIX:C within 30 min. Mean recovery was 1.3 ± 0.3 IU dL⁻¹ per IU kg⁻¹ for Factor IX Grifols^® and 1.0 ± 0.3 IU dL⁻¹ per IU kg⁻¹ for control products (P < 0.001). The mean terminal half‐life (t_1/2) for Factor IX Grifols^® was 26.7 h and 26.8 h for control product. Pharmacokinetic parameters after 6 months of treatment with Factor IX Grifols^® did not statistically differ from the parameters obtained with the first infusion. There were no adverse events related to Factor IX Grifols^® for the duration of the study. In conclusion, Factor IX Grifols^® has adequated pharmacokinetic properties comparable to the control plasma‐derived FIX and these parameters remain stable after 6 months of treatment. Factor IX Grifols^® can be an effective and safe plasma‐derived FIX concentrate for replacement therapy in haemophilia B patients.     

Safety and efficacy of plasma‐derived coagulation factor IX concentrate (AlphaNine® SD) in patients with haemophilia B undergoing surgical intervention: a single institution retrospective analysis

Summary. While coagulation factor replacement is essential in surgical intervention in haemophilia B patients, few studies are available on the safety and efficacy of plasma‐derived factor IX (FIX) for haemostasis during surgery. This retrospective study examined outcomes in these patients. A total of 20 patients who underwent 29 surgical procedures at the Hemophilia Treatment Center at Orthopaedic Hospital in Los Angeles, California, were identified and their inpatient charts were reviewed and abstracted. Outcomes included pre‐ and postoperative FIX dosing, recovery of FIX, blood loss, use of blood products, safety and haemostatic response. Identified patients had mild (10%), moderate (15%) or severe (75%) haemophilia B, and average age at surgery was 48.5 years. All surgical procedures were major (orthopaedic 89.7%; abdominal 10.3%), all were completed under general anaesthesia, and average time in surgery was 3.25 h. Average hospital length of stay was 11.0 days [standard deviation (SD) = 8.5] and all patients were discharged home. All patients were treated with AlphaNine^® SD at an average dose of 254.9 IU kg^?1 (SD = 65.4) on the day of surgery and the dose was adjusted over the course of hospital stay. Mean perioperative blood loss was 255.5 mL (SD = 283.1) and blood replacement was required in only two surgeries (6.9%). FIX recovery analysis performed preoperatively related well to FIX levels obtained. Identified patients had little blood loss perioperatively and had no bleeding related complications. Plasma‐derived FIX pre‐ and postoperatively appeared to be a safe and effective treatment in haemophilia B patients undergoing surgery.     

Head‐to‐head comparison of the pharmacokinetic profiles of a high‐purity factor IX concentrate (AlphaNine®) and a recombinant factor IX (BeneFIX®) in patients with severe haemophilia B

Head‐on comparative studies of factor IX (FIX) concentrates performed under standardized conditions are rarely conducted regardless of being a valuable instrument guiding health care providers towards better informed and cost‐effective decisions. This study is an extension of a multicentre study that assessed the efficacy, safety and pharmacokinetics (PK) of AlphaNine^® in 25 previously treated patients with severe haemophilia B (FIX:C ≤ 2%). After a washout period ≥7 days following the last PK performed with AlphaNine^® after a dose of 65–75 IU kg^?1, an identical PK study was performed with BeneFIX^® on 22 of the same patients. Venous blood samples for analysis were taken at baseline and at 0.25, 0.5, 1, 3, 6, 9, 24, 48, 72 and 74 h post infusion. The outcomes of the comparison of the PK parameters were as follows: Mean (±SD) in vivo recovery (IVR) was 1.3 ± 0.4 IU dL^?1 per IU kg^?1 for AlphaNine^® and 1.0 ± 0.3 IU dL^?1 per IU kg^?1 for BeneFIX^® (P < 0.01). Mean terminal half‐life, mean residence time, area under the curve, clearance and volume of distribution of BeneFIX^® were 36.0 ± 12.8 h, 39.3 ± 13.9 h, 1631 ± 467 IU h dL^?1, 0.046 ± 0.01 dL kg^?1 min^?1 and 1.75 ± 0.52 mL kg^?1 respectively. These values were not significantly different to those observed in AlphaNine^®, although BeneFIX^® displayed higher than expected IVR values and lower than expected clearance values. In conclusion, AlphaNine^® showed a comparable half‐life, but an IVR significantly higher than that of BeneFIX^®. This dissimilarity may have implications on dosing requirements for on‐demand treatment regimes affecting optimal resource allocation.     

An ultrapure plasma‐derived monoclonal antibody‐purified factor IX concentrate (Nonafact®), results of phase III and IV clinical studies

Summary. Nonafact^®, an ultrapure, monoclonal antibody‐purified factor IX concentrate (FIX) was developed to minimize risk of thrombotic complications and viral transmission. To investigate the pharmacokinetics, efficacy and safety, phase III/IV studies were performed in the Netherlands and Poland from 1996 to 2007. The mean half‐life, in vivo response and recovery of Nonafact^® were 18.7 (SD 2.0) h, 1.1 (SD 0.2) IU dL^?1 per IU kg^?1 b.w. of FIX infused and 49% (SD 10%), respectively. Eleven surgical procedures were performed in eight patients. During two surgeries, both high‐risk, blood loss was observed. No postoperative bleeding occurred. The in vivo recovery of FIX was higher than expected. In the phase III follow‐up study, 26 previously treated patients (PTP) were included with a median follow‐up of 1130 days. From the 1617 minor bleedings, 80.5% was stopped after a single infusion. In the phase IV study thirteen patients were treated for a median study period of 737 days. In the two follow‐up studies the investigators rated the effect of Nonafact^® as excellent/good in 95% of major bleedings. Surgeries for which Nonafact^® was given prophylactically were without bleeding problems. In total more than 10 million units of Nonafact^® were used during almost 120 person‐years. Only one minor adverse event was reported. No inhibitors, viral transmissions and thrombogenic events occurred. In conclusion, Nonafact^® is safe and provides excellent haemostasis in haemophilia B patients treated for spontaneous bleeding or undergoing surgical procedures. Due to the excellent in vivo recovery characteristic, treatment with Nonafact^® is cost saving compared to other FIX products.     

Continuous infusion of recombinant factor VIII formulated with sucrose in surgery: Non‐interventional,observational study in patients with severe haemophilia A

In haemophilia A, continuous infusion (CI) of FVIII perioperatively provides a more constant FVIII level than conventional bolus injections, avoiding low trough levels that could increase bleeding risk. Due to the low number of surgical cases in clinical trials, especially in haemophilia, more information on the clinical practice of CI from observational studies is helpful. We aimed to evaluate the effectiveness and safety of CI with recombinant factor VIII formulated with sucrose (rFVIII‐FS) in a typical surgery practice setting. This was a non‐interventional study in 12 centres. Patients with severe haemophilia A who received rFVIII‐FS by CI during and after surgery were included in this study if they had more than 150 exposure days (EDs) to any FVIII product and had no history of inhibitors before CI. Patients were observed during the entire course of CI, with monitoring up to 3 months thereafter. Twenty‐five patients with 28 surgeries were included in the analysis. Median age was 51.7 (range 10–75). Most (75%; 21/25) patients underwent orthopaedic surgeries. The median dose of rFVIII‐FS consumed during CI was 376 IU kg^?1 (range 157.9–3605.6 IU kg^?1) with a greater median dose for orthopaedic surgeries (424.0 IU kg^?1) compared to non‐orthopaedic surgeries (278.5 IU kg^?1). 95% of all FVIII measurements (214/224) were on target. Efficacy and tolerability were rated as good/excellent in 89.3% (25/28) of surgeries. No inhibitors were observed during or after surgery. This study demonstrates the effectiveness of CI with rFVIII‐FS during surgery in patients with severe haemophilia A in a clinical practice setting.     

An open clinical study assessing the efficacy and safety of Factor IX Grifols®, a high‐purity Factor IX concentrate,in patients with severe haemophilia B

Summary. Factor IX Grifols^® is a new high‐purity plasma‐derived FIX concentrate with two specific pathogen elimination steps. Until this study was performed, there were no detailed reports with an adequate number of patients on the clinical evaluation of this product. To determine the efficacy and safety of Factor IX Grifols^® for replacement therapy in previously treated patients with severe haemophilia B, this open, multicentre and non‐randomized study included 25 male subjects over the age of 12 with severe haemophilia B. Patients underwent prophylaxis and treatment of bleeding episodes with Factor IX Grifols^® for 1 year. The clinical efficacy and safety of this product were assessed. Forty percent of the patients were children and adolescents (12–17 years old). During the 12 months follow‐up, 1 446 000 IU of Factor IX Grifols^® were administered in 961 infusions (range 12–83 infusions per patient): 31% for prophylaxis and 69% for bleeding episodes. Only five major bleeding events were reported in two patients. These haemorrhages were successfully treated with a mean of 2900 IU per bleed (range 1500–4000 IU), and 1–3 infusions per bleed. The average time elapsed from the first infusion to resolution of bleeding was 43 h (median). Overall, haemostasis was rated as excellent or good by the investigator in 96% of the infusions. No product‐related adverse events were reported. Factor IX Grifols^® is an effective and safe Factor IX concentrate and can be considered as a first line option for replacement therapy in haemophilia B patients.     

Bioequivalence between two serum‐free recombinant factor VIII preparations (N8 and ADVATE®) – an open‐label,sequential dosing pharmacokinetic study in patients with severe haemophilia A

Summary. Recombinant coagulation factor VIII (rFVIII) concentrates provide a safe and efficacious replacement therapy for treatment and prevention of bleeding in patients with severe haemophilia A. The aim of this study was to compare the pharmacokinetic (PK) and safety profiles of two serum‐free rFVIII products: N8, a new rFVIII manufactured by Novo Nordisk and Advate^®, a marketed product. Patients with severe haemophilia A with >150 exposure days to FVIII, without current or past inhibitors, were enrolled in an open‐label, first human dose (FHD), multicentre trial. Twenty‐three patients first received a single dose of 50 IU kg^?1 body weight Advate^® followed by 50 IU kg^?1 body weight N8 at the next visit. A 4‐day washout period was required prior to each dosing. Blood samples for PK and safety analyses were drawn prior to dosing and at intervals up until 48 h postdosing. The PK parameters were based on FVIII clotting activity (FVIII:C) measurements. Occurrence of adverse events was closely monitored. The mean profiles of FVIII:C and all primary and secondary parameters for Advate^® and N8 were comparable. The 90% CI for the treatment ratio (Advate^®/N8) for all primary endpoints (incremental recovery, t_1/2, AUC and Cl), and the secondary endpoints (AUC_last and C_max) were within the bioequivalence interval of 0.8–1.25. There were no safety concerns in the study and no reports of inhibitor formation in the 72‐h period following exposure to a single N8 dose. In conclusion, N8 is bioequivalent to Advate^®. Furthermore, N8 is well tolerated in the FHD trial.     

Factor VIII and IX assays for post-infusion monitoring in hemophilia patients: Guidelines from the French BIMHO group (GFHT)

Replacement therapy with plasma-derived or recombinant FVIII and FIX (pdFVIII/pdFIX or rFVIII/rFIX) concentrates is the standard of treatment in patients with haemophilia A and B, respectively. Measurement of factor VIII (FVIII:C) or factor IX (FIX:C) levels can be done by one-stage clotting assay (OSA) or chromogenic substrate assay (CSA). The French study group on the Biology of Hemorrhagic Diseases (a collaborative group of the GFHT and MHEMO network) presents a literature review and proposals for the monitoring of FVIII:C and FIX:C levels in treated haemophilia A and B patients, respectively. The use of CSA is recommended for the monitoring of patients treated with pdFVIII or rFVIII including extended half-life (EHL) rFVIII. Except for rFVIII-Fc, great caution is required when measuring FVIII:C levels by OSA in patients substituted by EHL-rFVIII. The OSA is recommended for the monitoring of patients treated with pdFIX or rFIX. Large discordances in the FIX:C levels measured for extended half-life rFIX (EHL-rFIX), depending on the method and reagents used, must lead to great attention when OSA is used for measuring FIX:C levels in patients substituted by EHL-rFIX. Data of most of recent studies, obtained with spiked plasmas, deserve to be confirmed in plasma samples of treated patients.     

Multicentre,randomized, open‐label study of on‐demand treatment with two prophylaxis regimens of recombinant coagulation factor IX in haemophilia B subjects

Few randomized studies have reported on the use of factor IX (FIX) for secondary prophylaxis in haemophilia B patients. This study aimed to evaluate the efficacy and safety of two secondary prophylaxis regimens of recombinant coagulation FIX, nonacog alfa, compared with on‐demand therapy. Male subjects aged 6–65 years with severe or moderately severe haemophilia B (FIX:C ≤ 2, n = 50) and ≥12 bleeding episodes (including ≥6 haemarthroses episodes) within 12 months of study participation were enrolled in this multicentre, randomized, open‐label, four‐period crossover trial. The primary measure was the annualized bleeding rate (ABR) of two prophylactic regimens vs. on‐demand therapy. In the intent‐to‐treat group, mean ABR values were 35.1, 2.6 and 4.6 for the first on‐demand period, the 50 IU kg^?1 twice‐weekly period, and the 100 IU kg^?1 once‐weekly period respectively. Differences in ABR between the first on‐demand period and both prophylaxis regimens were significant (P < 0.0001); no significant differences were observed between prophylaxis regimens (P = 0.22). Seven serious adverse events occurred in five subjects, none related to study drug. Results demonstrated that secondary prophylaxis therapy with nonacog alfa 50 IU kg^?1 twice weekly or 100 IU kg^?1 once weekly reduced ABR by 89.4% relative to on‐demand treatment. Both prophylaxis regimens demonstrated favourable safety profiles in subjects with haemophilia B.     

Experience with Optivate®, a new high purity concentrate of factor VIII with von Willebrand factor,in patients undergoing surgery

Summary. The efficacy and safety of Optivate^® was assessed in 23 surgical operations, orthopaedic (12) including 5 revision arthroplasties, ophthalmic (1), ENT (1), dental (6), liver biopsy (2), and removal of portacath (1) on 15 teenagers and adults with severe haemophilia A. The preoperative dose was calculated to raise the FVIII concentration to 100 IU dL^?1. Subsequent doses were targeted to maintain at least 50 IU dL^?1. There were 11 major and 12 minor operations categorized as receiving intensive replacement therapy for ≥5 days or <5 days respectively. The median preoperative dose was 50.4 (range 18.2–88.2) IU kg^?1. The median incremental recovery based on this first dose in 10 procedures (5 patients) was 2.9 (range 2.4–3.4 IU dL^?1) per IU kg^?1. The daily doses decreased during the first 4 days of the study. The patients in this study received 173 infusions in total. Outcome was ‘good’ or ‘excellent’ for 19 (83%) of 23 operations, ‘uncertain’ in three procedures because an antifibrinolytic agent was used as well and for one procedure outcome was not assessed. Tolerance was good. There were no excessive bleeds, no inhibitors and no virus transmissions.     

Pharmacokinetics of Optivate®, a high‐purity concentrate of factor VIII with von Willebrand factor,in patients with severe haemophilia A

Summary. Optivate^® is a high purity factor VIII/von Willebrand factor (FVIII/VWF) concentrate, which is manufactured using two antiviral processes: solvent/detergent and terminal dry heating (80°C for 72 h). A multicentre, non‐randomized open‐label study in 15 patients was conducted to test the pharmacokinetics (PK) of Optivate^®. PK variables were analysed for the patients’ prior FVIII product (PK1), their first dose of Optivate^® (PK2) and at 3 months therapy (PK3). Mean non‐compartmental half‐lives (h) were 14.1, 12.4 and 12.1, respectively (P = 0.45), mean clearances (mL h^?1 kg^?1) were 3.6, 3.2 and 3.1, respectively (P = 0.051), MRTs (h) were 19.0, 17.3 and 17.4, respectively (P = 0.39) and mean AUC_0–48h (h IU mL^?1) were 14.3, 15.4 and 16.6, respectively (P = 0.051) and mean AUC_0–∞ (h IU mL^?1) were 15.9, 16.4 and 17.9, respectively (P = 0.18). The recovery data from this PK study was aggregated with recovery data collected from another study, with similar design but devoid of the other PK measurements. A total of 309 recoveries were conducted in 70 patients. The overall mean recovery per subject across 27 Optivate^® batches was 2.7 IU dL^?1 per IU kg^?1. There were no clinical differences between Optivate^® and other FVIII products, and except for volume of distribution (Vd), no statistically significant differences were seen with respect to any of the other PK variables, or in recovery between weeks 0 and 12. Therefore, the PK of FVIII is not affected by the processes used to manufacture Optivate^®, which can be expected to be effective in the management of patients with haemophilia A.