Clinical efficacy, safety and pharmacokinetic properties of the factor VIII concentrate Haemoctin® SDH in previously treated patients with severe haemophilia A

Clinical efficacy, safety and pharmacokinetic properties of the high-purity double-virus inactivated plasma-derived factor VIII concentrate Haemoctin SDH (pdFVIII) were evaluated in three prospective open-label uncontrolled studies in previously treated patients (PTPs) with severe haemophilia A. The pharmacokinetic properties assessed at baseline and after 3 months of treatment are in accurate accordance with published data and remain unchanged over time (study A, n = 12). Mean terminal elimination half-life was 11.8 and 11.9 h, mean incremental recovery (IU dL(-1)/IU kg(-1)) was 2.3 and 2.0, respectively. Long-term efficacy and safety, in particular the potential immunogenicity, were investigated in a total of 53 PTPs (studies A and B) treated prophylactically and on-demand, as required. PdFVIII has shown to be effective in preventing and controlling bleeding episodes; 23.5% of patients were free of bleeding events. A total of 177 haemorrhages occurred with 74.0% resolving after a single infusion, 87.6% within two infusions. 98.3% of responses reported on haemorrhages were rated as 'excellent' or 'good'. Moreover, 'excellent' haemostatic efficacy has been demonstrated in 10 surgical procedures including general and severe orthopaedic interventions (study C). No complication occurred in any surgery. Few adverse events were reported, one patient developed a high-titre FVIII inhibitor without clinical relevance. In all three studies, over 6 million units were administered in nearly 4300 infusions, approximately 94% units or infusions were given for prophylaxis and only 6% for treatment on-demand. In conclusion, pdFVIII has shown to be effective, safe and well tolerated in long-term prophylaxis and treatment on-demand as well as after minor and major surgical procedures.     

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.     

Reformulated BeneFix®: efficacy and safety in previously treated patients with moderately severe to severe haemophilia B

BeneFix, the only recombinant factor IX (FIX), has been reformulated. The reformulation involves a change in diluent and allows for more concentrated infusions of recombinant FIX. A double-blind, randomized, pharmacokinetic (PK) crossover study demonstrated that reformulated BeneFix was bioequivalent to original BeneFix and follow-up PK evaluation after 6 months of treatment demonstrated the PK stability of reformulated BeneFix after multiple exposures. Favourable efficacy and safety profiles, consistent with those already well-established for original BeneFix, were observed: 81.1% of haemorrhages resolved with only a single infusion; 85.3% of initial treatment response ratings were Excellent or Good; more than half of the subjects using reformulated BeneFix for routine prophylaxis (11 of 17, 64.7%) had no spontaneous haemorrhages during their 6-12 month course of prophylactic treatment, with an overall spontaneous bleeding rate of 0.72 year(-1); and for the single surgical procedure (knee washing), treatment was rated Useful. In addition, there was no FIX inhibitor development, allergic-type manifestations, or thrombogenic complications with more than 1100 infusions (nearly 5.2 million IUs) administered in this trial. All efficacy and safety outcomes from this study were achieved with more concentrated recombinant protein infusions than that possible with original BeneFix, and utilization of the 2000 IU per vial dosage strength, newly introduced with the reformulated product, was high (>62%). The reformulation of BeneFix allows smaller delivery volumes and an increased choice of dosage strengths without altering the PK properties (including incremental recovery and half-life) or the established efficacy and safety profile of recombinant FIX.     

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 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.     

Role of enhanced half‐life factor VIII and IX in the treatment of haemophilia

Treatment of congenital haemophilia with factor VIII and IX concentrates often requires frequent infusions. This has obvious implications in establishing effective administration strategies and, in turn, adherence. To overcome these issues, three main technologies – polyethylene‐glycol, Fc‐neonatal IgG₁ and albumin fusion products – have emerged into various stages of clinical development. Published data indicates an approximately 1·5‐ and fivefold increase in half‐life of factor VIII and IX, respectively, compared to standard recombinant concentrates. Studies into efficacy and safety are starting to be published. Monitoring and optimal use of these new concentrates remains unknown. Weekly factor IX prophylaxis appears to be a feasible prophylactic regimen in haemophilia B patients. Weekly longer‐acting FVIII is unlikely to provide adequate prophylaxis in most patients with haemophilia A but may reduce the frequency of infusions. Ongoing clinical trials and real life experience will help shape how these products can be used in practice and their cost effectiveness. The drive for convenience however should not overshadow the ultimate goal of prophylaxis, namely, preventing bleeding and arthropathy.     

Efficacy and safety of monoclonal antibody purified factor IX concentrate in haemophilia B patients undergoing surgical procedures

The present study summarizes results of the efficacy and safety of monoclonal antibody (MAb) purified factor IX concentrate [Mononine® Coagulation Factor IX (Human), Centeon L.L.C., King of Prussia, PA, USA] for surgical prophylaxis in 74 patients with mild, moderate or severe haemophilia B who underwent a total of 81 different operative interventions. Surgical procedures included joint replacement/arthroplasty ( n = 12), gastrointestinal (GI) or rectal surgery ( n = 6), synovectomy/osteotomy ( n = 8), hernia repair ( n = 4), central catheter insertion ( n = 3), ENT surgery ( n = 4), dental procedures ( n = 14), biopsies ( n = 2), gynaecological procedures ( n = 4), ophthalmological surgery ( n = 4), spinal surgery ( n = 4), urogenital surgery ( n = 2), other orthopaedic surgery ( n = 4) or other miscellaneous procedures ( n = 10). All patients demonstrated haemostasis rated as 'excellent' by the investigators. No patients experienced clinically evident thromboembolic complications during treatment with MAb factor IX. These results, from a large and varied random group of patients, demonstrate that this highly purified factor IX concentrate is safe and effective for surgical prophylaxis in patients with haemophilia B, including those patients who have experienced thromboembolic complications during prior treatment with prothrombin complex concentrates.     

Kinetics of factor IX activity differ from that of factor IX antigen in patients with haemophilia B receiving high-purity factor IX replacement

Pharmacokinetic studies in haemophilia B have found in vivo recovery of FIX (FIX) to be uniformly lower than the factor VIII recovery in haemophilia A. We hypothesized that this lower recovery could result from rapid binding to high-affinity receptors on platelets and endothelium. To test this hypothesis, we evaluated the kinetics of FIX activity and protein in haemophilia B patients. Twelve patients were enrolled in a double dosing, crossover study with two high-purity FIX concentrates, AlphaNine SD and MonoNine. Subjects were given 40 U kg-1 of FIX concentrate and blood samples were taken at 15, 30, and 60 min. A second infusion of 40 U kg-1 was given after the 60 min blood sample and further blood samples removed at 15, 60, 120, and 360 min after the second dose. Patients were infused with the alternate concentrate at least 7 days later. Plasma samples were assayed for FIX activity by coagulation assay and antigen by RIA. FIX antigen in the infused concentrates was measured and quantified as microg U-1. There was no difference between the two FIX concentrates (AlphaNine vs. MonoNine) in the initial (15 min) activity (57% +/-1 19% vs. 53% +/-1 12%) and antigen (62% +/-1 16% vs. 55% +/-1 19%) recoveries. Recoveries after the second FIX dose were not statistically different than those observed after the first FIX dose. In one patient, a doubling of the initial infusion dose did not increase FIX recovery after the second FIX dose. However, the recovery of FIX antigen was significantly greater than the recovery of FIX activity and the differences became more significant in the post-15 min samples. We calculated a ratio of plasma FIX antigen to FIX activity in microg U-1. Average antigen to activity ratio increased from 5.8 +/-1 1.9 microg U-1 at 15 min to 7.1 +/-1 2.2 microg U-1 at 60 min. At 420 min the ratio increased to 9.3 +/-1 2.4 microg U-1. Although these studies failed to demonstrate a significant FIX receptor pool, they did demonstrate a phenomenon of progressive loss of biologic activity of the FIX protein after infusion of FIX concentrates.     

Recombinant factor IX (BAX326) in previously treated paediatric patients with haemophilia B: a prospective clinical trial

A newly developed recombinant factor IX (BAX326¹) was investigated for prophylactic use in paediatric patients aged <12 years with severe (FIX level <1%) or moderately severe (FIX level 1–2%) haemophilia B. The aim of this prospective clinical trial was to assess the safety, haemostatic efficacy and pharmacokinetic profile of BAX326 in previously treated paediatric patients. BAX326 was administered as prophylaxis twice a week for a period of 6 months, and on demand for treatment of bleeds. Safety was assessed by the occurrence of related AEs, thrombotic events and immunologic assessments. Efficacy was evaluated by annualized bleeding rate (ABR), and by treatment response rating (excellent, good, fair, none). PK was assessed over 72 h. None of the 23 treated paediatric subjects had treatment‐related SAEs or AEs. There were no thrombotic events, inhibitory or specific binding antibodies against FIX, rFurin or CHO protein. Twenty‐six bleeds (19 non‐joint vs. 7 joint bleeds) occurred (mean ABR 2.7 ± 3.14, median 2.0), of which 23 were injury‐related. Twenty subjects (87%) did not experience any bleeds of spontaneous aetiology. Haemostatic efficacy of BAX326 was excellent or good for >96% of bleeds (100% of minor, 88.9% of moderate and 100% of major bleeds); the majority (88.5%) resolved after 1–2 infusions. Longer T_1/2 and lower IR were observed in younger children (<6 years) compared to those aged 6 to 12 years. BAX326 administered as prophylactic treatment as well as for controlling bleeds is efficacious and safe in paediatric patients aged <12 years with haemophilia B.