Nanofiltration is incorporated into the manufacturing processes of many protein biopharmaceuticals to enhance safety by providing the capacity to retain pathogens while allowing protein drugs to pass through the filter. Retention is mainly a function of size; however, the shape of the pathogen may also influence retention. The ability of the Viresolve(®) Pro nanofilter to remove different sized viruses during the manufacture of a Coagulation Factor IX (Alphanine(®) SD) was studied at varying ionic strength, a process condition with the potential to affect virus shape and, hence, virus retention. Eight viruses were tested in a scale-down of the nanofiltration process. Five of the viruses (EMCV, Reo, BVDV, HIV, PRV) were nanofiltered at normal sodium processing conditions and three (PPV, HAV and WNV) were nanofiltered at higher and lower sodium. Representative Reduction Factors for all viruses were ≥4.50 logs and removal was consistent over a wide range of ionic strength.

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.

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.

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.

This study employed sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting to assess the purity of seven high purity factor IX concentrates: Aimafix (Aima), AlphaNine-SD (Alpha Therapeutic), Factor IX VHP (Biotransfusion), Immunine (Immuno), Mononine (Armour Pharmaceutical), Nanotiv (Kabi Pharmacia), and 9MC (Blood Products Laboratory). The mean specific activity of these products ranged from 68 U factor IX/mg (Aimafix) to 246 U factor IX/mg (Mononine). SDS-PAGE analysis showed that the highest purity product, Mononine, had a single contaminating band under non-reducing conditions. Two additional bands were detected when this product was analyzed under reducing conditions. All other products had multiple contaminating bands that were more apparent under reducing than non-reducing conditions. The immunoblot for factor IX showed a dominant factor IX band for all products. In addition, visible light chain of factor IX was detected for AlphaNine-SD, Factor IX VHP, Immunine, Mononine, Nanotiv, and 9MC, suggesting that the factor IX in these products had undergone partial activation to factor IXa. Another contaminating band was visible at 49,500 for all of the products except 9MC. In addition to this band, high molecular weight contaminants were apparent for some products, most notably AlphaNine-SD. The identity of these bands is unknown. Immunoblotting failed to demonstrate factor VII as a contaminant of any of the high purity products, although factor VIIa could be detected in some lots of Immunine, Nanotiv, and 9MC by a clot-based assay. Factor X contaminated Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Nanotiv, and 9MC, but activation products of factor X were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Constituents other than factor IX have been implicated as etiologic agents for thrombotic complications in patients receiving prothrombin complex concentrates (PCCs). In vitro studies, in vivo animal models, and clinical evaluations in patients with hemophilia B indicate that high-purity factor IX concentrates contain significantly fewer potentially thrombogenic contaminants than PCCs. A recent in vitro study from our laboratory used highly sensitive assays to analyze the relative purity of these newer products. The following products were studied using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting: Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Mononine, Nanotiv, and 9MC (now known as Replinine). The mean specific activity of the high-purity factor IX products ranged from 68 IU factor IX/mg (Aimafix) to 246 IU factor IX/mg (Mononine). SDS-PAGE analysis under reducing and nonreducing conditions showed that Mononine had the fewest contaminating bands. The immunoblot to detect factor IX showed a dominant factor IX band for all products, visible light chain of factor IX for all products except Aimafix, and another contaminating band visible at 49,500 daltons for all products except 9MC. High molecular weight contaminants were apparent for some products. Factor VIIa was detected in some lots of Immunine, Nanotiv and 9MC. Factor X and prothrombin contaminated Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Nanotiv and 9MC. Thus, Mononine, Nanotiv and 9MC demonstrated the highest purity but no product was totally free of contaminants.