Recombinant FVIIIFc-VWF-XTEN Demonstrates Significant Bioavailability Following Subcutaneous Administration in Hemophilia A Mice

Abstract All currently marketed Factor VIII (FVIII) molecules are administered intravenously (IV) for the treatment of hemophilia A (HemA). Conventional FVIII prophylaxis requires a dosing interval of three times per week to every other day. This frequent dosing regimen necessitates repeated venous access and is associated with complications such as secondary infection in children with a venous port/catheter. More recently, extended half-life variants of FVIII have been shown in clinical trials to decrease the dosing interval to twice weekly or less frequent IV dosing, which reduces, but does not eliminate, the burden of treatment. A FVIII molecule with further prolonged half-life and subcutaneous (SQ) delivery potential could significantly relieve the treatment burden for HemA patients and improve the adherence rate to FVIII prophylaxis. Recombinant FVIIIFc-VWF-XTEN has been shown to not bind endogenous VWF, and is able to achieve a 4-fold extension of half-life in hemophilia A mice compared to conventional FVIII, well beyond the approximately 2-fold half-life extension limit demonstrated by other long-acting FVIII variants that bind endogenous VWF. It comprises of two polypeptide chains: 1) a single chain B-domain deleted FVIIIFc-XTEN chain with a XTEN polypeptide inserted at the B-domain region of native FVIII sequence, and 2) a VWF D'D3-XTEN-Fc chain xtend one that n TEN fragemnt o FVIII prophylaxis.ntial rity of the patients depending on the half-life of the FVIII molecule. with a second XTEN polypeptide inserted between D'D3 domain and Fc. The rFVIIIFc-VWF-XTEN protein was produced in HEK293 cells and affinity purified using VIIISelect resin. The pharmacokinetic (PK) profiles of intravenously (IV) and subcutaneously (SQ) administered rFVIIIFc-VWF-XTEN were compared to those of rFVIII in HemA mice. The duration of the in vivo efficacy of rFVIIIFc-VWF-XTEN post-SQ delivery was assessed in a HemA mouse tail vein transection (TVT) bleeding model. After intravenous dosing in HemA mice, we observed a linear PK profile for rFVIIIFc-VWF-XTEN within the therapeutic dose range (25, 50, 100 IU/kg). The half-life of IV-administered rFVIIIFc-VWF-XTEN was about 37 h, which is more than 4-fold longer than that of rFVIII. In addition, animals that received 25 IU/kg of rFVIIIFc-VWF-XTEN treatment retained 5% of normal FVIII activity at 120 h post-dosing, which suggests the potential for full protection from spontaneous bleeding in this animal model. When delivered subcutaneously, the bioavailability of rFVIIIFc-VWF-XTEN was 20%, a significant increase compared to the bioavailability of rFVIII (less than 1%). Starting at 24 h post-dosing, subcutaneous administration of rFVIIIFc-VWF-XTEN achieved plasma FVIII levels that were equal to or greater than those attained with rFVIII delivered intravenously at the same dose. In addition, greater than 5% of normal circulating FVIII level was observed at 96 h post SQ administration of rFVIIIFc-VWF-XTEN with a 100 IU/kg dose, which provided 80% protection on survival in mice subjected to tail vein transection injury. These results suggest that rFVIIIFc-VWF-XTEN could enable less frequent FVIII replacement treatment compared to rFVIII even when administered subcutaneously. The VWF independence of rFVIIIFc-VWF-XTEN enables a 4-fold increase in circulating half-life compared to that of rFVIII. Also, the addition of D'D3 domains and the two XTEN insertions dramatically increases subcutaneous bioavailability to 20%, compared to less than 1% with conventional FVIII. These unique properties of rFVIIIFc-VWF-XTEN make it a potential candidate for both IV and SQ treatments for hemophilia A. Disclosures Drager: Biogen: Employment, Equity Ownership. Patarroyo-White:Biogen: Employment, Equity Ownership. Chao:Biogen: Employment, Equity Ownership. Ismail:Biogen: Employment. Liu:Biogen: Employment, Equity Ownership. Holthaus:Biogen: Employment. Chhabra:Biogen: Employment, Equity Ownership. Kulman:Biogen: Employment. Schellenberger:Amunix Operating Inc: Employment. Liu:Biogen: Employment, Equity Ownership. Peters:Biogen: Employment.

Download Full-text

Evaluation of Enhanced in Vitro Plasma Stability of a Novel Long Acting Recombinant FVIIIFc-VWF-XTEN Fusion Protein

Blood ◽

10.1182/blood.v126.23.2279.2279 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2279-2279 ◽

Cited By ~ 3

Author(s):

Ekta Seth Chhabra ◽

Nancy Moore ◽

Chris Furcht ◽

Amy M Holthaus ◽

Jiayun Liu ◽

...

Keyword(s):

Fusion Protein ◽

Half Life ◽

Hek293 Cells ◽

Clotting Factor ◽

Plasma Stability ◽

Single Chain ◽

Employment Equity ◽

Equity Ownership

Abstract INTRODUCTION More than 95% of circulating clotting factor VIII (FVIII) exists in a non-covalent complex with von Willebrand Factor (VWF). While VWF stabilizes and protects FVIII from its clearance pathways, it also subjects FVIII to VWF-mediated clearance. Thus, interaction with VWF imposes a limitation on the extent of FVIII half-life extension achieved by current technologies (Fc fusion, PEGylation etc.). Recombinant FVIIIFc-VWF-XTEN (rFVIIIFc-VWF-XTEN) is a novel fusion protein, consisting of the FVIII binding D'D3 domains of VWF fused to a single chain rFVIIIFc (scFVIIIFc). Appending the domains of VWF to FVIII provides the protection and stability of endogenous VWF, while avoiding the limitation imposed by VWF clearance. Besides D'D3 domains, it also contains two XTEN linkers. XTEN is an unstructured polypeptide consisting of six amino acids repeats (Gly, Ala, Pro, Glu, Ser, Thr). Fusion of XTEN to a protein reduces the rate of clearance and degradation of the fusion protein. In rFVIIIFc-VWF-XTEN, one XTEN linker replaces the B-domain of FVIII and other is attached to the D'D3 domains. In preclinical studies, this protein has shown >4-fold prolonged half-life and similar in vivo acute efficacy compared to rFVIII. In the current study, we examined the impact of various modifications on the in vitro plasma stability of rFVIIIFc-VWF-XTEN protein. MATERIALS AND METHODS rFVIIIFc-VWF-XTEN is a fusion protein which is expressed as a dual chain molecule. One chain expresses the D'D3 domains linked to a Fc monomer through an XTEN linker. This polypeptide is co-expressed with a single chain rFVIIIFc monomer to generate a dimer, via the disulfide-bond between the Fc domains. To assess the in vitro plasma stability, fusion proteins were expressed in HEK293 cells, purified and incubated with plasma from FVIII KO (Hem A) or FVIII/VWF DKO mice, for various time periods at 37 degree centigrade. After the desired incubation time, plasma stability of the recombinant proteins was determined by FVIII chromogenic activity assay. Results and Conclusions rFVIIIFc-VWF-XTEN fusion protein showed significantly enhanced in vitro plasma stability compared to rFVIII. In FVIII KO plasma, rFVIII started losing activity by 4 hours, and by 24 hours it lost more than 80% of its activity. The decline in activity was more pronounced and rapid when rFVIII was incubated with FVIII/VWF DKO plasma, mainly due to the absence of protection provided by VWF. Conversely, in the case of rFVIIIFc-VWF-XTEN, there was no significant drop in activity even after 6 hours (in both FVIII KO and DKO plasma). By 24 hours, only 10-15% activity reduction was observed in FVIII KO plasma and about a 35% decrease in DKO plasma. Further studies were conducted to evaluate various parameters which contributed to the improved stability of this fusion protein. Our results suggest that there are multiple factors which contribute to the overall stability of rFVIII-VWF-XTEN protein. These include: presence of covalently attached D'D3 domains, enhanced stability of single chain FVIII isoform used in the fusion protein and presence of the XTEN linker in the B-domain of FVIII. These data suggest that superior plasma stability of this novel fusion protein might be a contributing factor to its prolonged in vivo half-life and efficacy. Disclosures Seth Chhabra: Biogen: Employment, Equity Ownership. Moore:Biogen: Employment, Equity Ownership. Furcht:Biogen: Employment, Equity Ownership. Holthaus:Biogen: Employment. Liu:Biogen: Employment, Equity Ownership. Liu:Biogen: Employment, Equity Ownership. Schellenberger:Amunix Operating Inc: Employment. Kulman:Biogen: Employment. Salas:Biogen: Employment, Equity Ownership. Peters:Biogen: Employment.

Download Full-text

Perioperative Efficacy of an Extended Half-Life, Pegylated, Full-Length, Recombinant Factor VIII (BAX 855) in Individual Procedures

Blood ◽

10.1182/blood.v126.23.2299.2299 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2299-2299

Author(s):

Brigitte Brand ◽

Ralph A. Gruppo ◽

Tung T. Wynn ◽

Laimonas Griskevicius ◽

Maria Fernanda Lopez Fernandez ◽

...

Keyword(s):

Blood Loss ◽

Factor Viii ◽

Half Life ◽

Research Funding ◽

Hemophilia A ◽

Full Length ◽

Recombinant Factor Viii ◽

Employment Equity ◽

Major Procedure ◽

Equity Ownership

Abstract BAX 855 is a pegylated full-length recombinant factor VIII (PEG rFVIII) built on rFVIII (ADVATE) with an extended half-life and is intended for prophylaxis and the treatment of bleeding in patients with hemophilia A.1 This phase 3 surgery study is evaluating the efficacy and safety of BAX 855 for the perioperative control of hemostasis. Patients' informed consent and appropriate ethics committee approvals were obtained. Elective procedures were prospectively classified (major or minor) by the investigator/surgeon and major emergency surgeries were excluded. The target trough FVIII levels for major and minor surgeries were to be ≥80% and 30-60%, respectively. Each patient's pharmacokinetic (PK) profile was used to guide the BAX 855 dose and infusion frequency. BAX 855 PK were consistent with previous PK assessments with terminal half-life ranging from 8.81 to 18.06 hours for the 15 patients in this study. In this interim analysis, 15 male previously treated patients (PTPs) ranging from 19 to 52 years of age have undergone 15 procedures in 7 countries. Individual procedure profiles are compiled to evaluate the control of hemostasis for BAX 855. There were 11 major procedures: 6 orthopedic (3 knee replacements, 2 arthroscopic synovectomies, 1 elbow cyst extirpation) and 5 non-orthopedic procedures (3 dental [root canals for 2 teeth, 2 extractions of ≥4 teeth, 1 radicular cyst removal], 1 cardiovascular [mediport placement], 1 abdominal [gastric band insertion]). The 4 minor surgeries comprised 1 synoviorthesis, 1 dental, 1 dermatological and 1 endoscopy (radiosynovectomy) procedure. Efficacy was evaluated by the surgeon or investigator's rating of hemostatic control using 4-point scale which was based on blood loss and by comparing actual blood loss with predicted blood loss which was specified by the surgeon for non-hemophilia patients prior to the procedure. For all procedures, the hemostatic control of BAX 855 was rated "excellent" for the intraoperative (during the procedure), postoperative (24 hours after completion of the procedure), and perioperative (from start of the procedure until discharge or day 14) periods, except for 1 minor dental procedure in which postoperative efficacy was rated "good" and 1 minor procedure in which a postoperative rating was not provided (for both of these procedures intra- and perioperative ratings were "excellent"). Actual blood loss (ABL) for the intraoperative and postoperative periods were compared with predicted average and maximum values. Intraoperative ABL for all minor and major procedures was less than or equal to predicted averages and maximums, except for 1 minor procedure in which the ABL was greater than the predicted average and maximum and 1 major procedure which did not have ABL recorded. Postoperative ABL was less than or equal to predicted averages and maximums for 4/4 minor procedures and 5 major procedures. For 4 major procedures, postoperative ABL was greater than or equal to predicted average, but less than predicted maximums. For the remaining major procedure (synovectomy with general anesthesia) with reported ABL, postoperative ABL was greater than the predicted the average and maximum - the efficacy assessments at all periods for this procedure were considered "excellent". These results demonstrate the efficacy of BAX 855 for the perioperative control of hemostasis in patients with severe hemophilia A. 1 Konkle BA, Stasyshyn O, Chowdary P et al. Pegylated, full-length, recombinant factor VIII for prophylactic and on-demand treatment of severe hemophilia A. Blood. 2015; Link to Publisher's site: http://www.bloodjournal.org/content/bloodjournal/early/2015/07/08/blood-2015-03-630897.full.pdf Disclosures Brand: CSL Behring: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; Baxalta: Consultancy, Research Funding; Novo Nordisk: Consultancy; Biotest: Consultancy. Gruppo:Baxalta: Consultancy, Research Funding; Novo Nordisk: Consultancy; Pfizer: Consultancy; Alexion: Speakers Bureau. Wynn:Baxalta: Research Funding. Griskevicius:Novartis: Consultancy, Research Funding; Baxalta: Research Funding. Fernanda Lopez Fernandez:Baxalta: Research Funding. Dvorak:Baxalta: Employment, Equity Ownership. Patrone:Baxalta: Employment, Equity Ownership. Abbuehl:Baxalta: Employment, Equity Ownership.

Download Full-text

Platelet-Targeted rFVIIa-Xten Improves Thrombin Generation and Fibrin Formation Compared to Recombinant FVIIa

Blood ◽

10.1182/blood.v126.23.2269.2269 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2269-2269 ◽

Cited By ~ 2

Author(s):

Maria M. Aleman ◽

Elena N. Kistanova ◽

Nancy Moore ◽

Volker Schellenberger ◽

Robert Peters ◽

...

Keyword(s):

Half Life ◽

Thrombin Generation ◽

Hemophilia A ◽

Platelet Rich Plasma ◽

Life Extension ◽

Employment Equity ◽

On Demand ◽

Fibrin Formation ◽

Fibrin Network ◽

Equity Ownership

Abstract The development of inhibitors to replacement plasma factors in hemophilia is an ongoing clinical complication. Bypass therapies, such as recombinant factor VIIa (rFVIIa), have emerged as important alternative on-demand strategies for hemophilic patients with inhibitors to treat spontaneous bleeds and prevent bleeding during surgery. However, general prophylaxis strategies for hemophilia inhibitor patients are lacking. An attractive approach for effective prophylaxis and on-demand treatment includes engineering potent rFVIIa variants with prolonged pharmacokinetics. Because the primary mechanism of action of rFVIIa is thought to occur on the platelet surface, we combined rFVIIa with platelet-targeting and XTEN half-life extension technologies to improve its pharmacokinetic profile and procoagulant activity. Platelet-targeting was achieved by recombinant fusion of an antibody fragment which binds the human alpha IIb integrin. Half-life extension was achieved by fusion of an XTEN polypeptide which increases the hydrodynamic radius, and therefore half-life, of rFVIIa. We have shown that these rFVIIa modifications improve the pharmacokinetics and efficacy of rFVIIa in vivo in humanized alpha IIb transgenic hemophilia A mice. The goal of the current study was to evaluate and compare thrombin generation and fibrin formation kinetics in hemophilic platelet-rich plasma in the presence of platelet-targeted rFVIIa-XTEN or rFVIIa. To achieve this, platelet-rich plasma from normal human donors was treated with an inhibitory factor VIII antibody to model hemophilia A and spiked with doses of platelet-targeted rFVIIa-XTEN or rFVIIa. Reactions were triggered with low tissue factor and recalcification. Thrombin generation (n=9) was monitored by calibrated automated thrombography and fibrin formation (n=7) was monitored optically on a plate reader. Non-linear regression analysis of dose responses was used to determine EC50 values for each parameter for each donor. Platelet-targeted rFVIIa-XTEN increases the rate and peak of thrombin generation with 2- to 6-fold lower EC50 values (peak and rate, respectively) than rFVIIa. These data were confirmed by thrombin generation in platelet-rich plasma from 1 hemophilia A donor and 1 hemophilia B donor which demonstrated similar responses to platelet-targeted rFVIIa-XTEN with 2.5- to 5-fold lower EC50 values (peak and rate, respectively) than rFVIIa. Notably, platelet count-dependent changes in thrombin generation activity were similar between platelet-targeted rFVIIa-XTEN and rFVIIa. Fibrin formation analysis indicated platelet-targeted rFVIIa-XTEN increases the rate and time to plateau of fibrin formation with 5- to 13-fold lower EC50 values (rate and time to plateau, respectively) than rFVIIa. Analysis of fibrin network structure by confocal microscopy indicated platelet-targeted rFVIIa-XTEN increases fibrin network density in platelet-rich plasma clots. Together, these data show platelet-targeted rFVIIa-XTEN has more procoagulant activity than rFVIIa by supporting more thrombin generation and faster fibrin formation and suggest our approach has the potential to be an effective alternative for the treatment and prevention of bleeds in hemophilia patients with inhibitors. Disclosures Aleman: Biogen: Employment, Equity Ownership. Kistanova:Biogen: Employment, Equity Ownership. Moore:Biogen: Employment, Equity Ownership. Schellenberger:Amunix Operating Inc: Employment. Peters:Biogen: Employment. Salas:Biogen: Employment, Equity Ownership.

Download Full-text

Pharmacokinetics Of Recombinant Factor VIII Fc Fusion Protein (rFVIIIFc) in Pediatric Subjects With Hemophilia A: An Interim Analysis Of The Kids A-LONG Study

Blood ◽

10.1182/blood.v122.21.3609.3609 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3609-3609

Author(s):

Guy Young ◽

Johnny Mahlangu ◽

Beatrice Nolan ◽

Simon Brown ◽

Leonard A. Valentino ◽

...

Keyword(s):

Board Of Directors ◽

Half Life ◽

Interim Analysis ◽

Research Funding ◽

Hemophilia A ◽

Additional Time ◽

Employment Equity ◽

Advisory Committees ◽

Age Cohorts ◽

Equity Ownership

Abstract Introduction Prophylactic factor VIII (FVIII) administration is the standard of care for patients with severe hemophilia A; however, frequent injections are required to maintain protective factor levels. To reduce injection frequency, we developed a long-lasting recombinant FVIII Fc fusion protein (rFVIIIFc) consisting of one rFVIII molecule covalently linked to the Fc domain of immunoglobulin G1 (IgG1). rFVIIIFc had a 1.53-fold higher half-life and a 36% reduction in clearance (CL) versus FVIII (Advate®) in a phase 3 study of adults and adolescents (J Thromb Haemost. 2013;11[2]:169). The Kids A-LONG study (NCT01458106) was designed to investigate the pharmacokinetics (PK), safety, and efficacy of rFVIIIFc in pediatric subjects with hemophilia A who were previously treated with FVIII products. The objective of this planned interim analysis was to determine the PK parameters of rFVIIIFc in pediatric subjects and compare these parameters to those of the subjects' prescribed FVIII products. Methods This multi-center, open-label, phase 3 study is currently enrolling previously-treated subjects aged<12 years with severe hemophilia A (≤1 IU/dL endogenous FVIII), at least 50 exposure days (EDs) to FVIII products, and no history of or current inhibitors to FVIII. Subjects are stratified into two age cohorts (<6 years and 6 to<12 years). All subjects are started on a twice-weekly rFVIIIFc prophylactic regimen 25 IU/kg on day 1 and 50 IU/kg on day 4 with subsequent dosing adjustment based on PK data and bleeding frequency. The primary endpoint is the incidence of inhibitor development. A sequential PK analysis is performed to compare the PK parameters of rFVIIIFc with that of the prescribed FVIII product. Subjects undergo a washout period of at least 72 hours before receiving the first dose of either FVIII or rFVIIIFc. For FVIII PK analysis, subjects receive 50 IU/kg of their currently prescribed FVIII product with sampling at baseline and at 4 additional time points after for up to 48 hours. For rFVIIIFc PK assessment, subjects receive 50 IU/kg rFVIIIFc, with sampling prior to rFVIIIFc administration and at 5 additional time points after for up to 72 hours. PK parameters were derived from FVIII activity-over-time profiles estimated by the non-compartmental analysis using the PK data analysis software Phoenix™ WinNonlin 6.2.1.51. FVIII activity was measured by the one-stage clotting assay calibrated against a commercially available FVIII plasma standard. A data cut-off date of 8 February 2013 was used to report PK data in this interim analysis. Results At the time of this analysis, 52 subjects were enrolled and received at least one dose of FVIII and/or rFVIIIFc. Of 37 subjects with evaluable PK profiles, 30 received both FVIII and rFVIIIFc. For PK assessment of FVIII, 7 different FVIII products were used, of which Advate ®, Haemosolvate®, and Kogenate FS® were the most common. A comparison of PK parameters for rFVIIIFc versus FVIII for both age cohorts demonstrated that rFVIIIFc had a longer half-life (∼1.5 fold increase) and a lower CL (30% to 50% reduction) than FVIII (Table 1). Conclusion In comparison to currently available FVIII products, rFVIIIFc had an extended half-life and reduced CL in children. These results are in agreement with those previously observed in adults and adolescents. The final analysis of the Kids A-LONG study will provide additional PK information and evaluate the safety and efficacy of rFVIIIFc in children. Disclosures: Young: Novo Nordisk: Consultancy, Honoraria; Biogen Idec, Baxter, Kedrion: Consultancy. Mahlangu:Bayer, Novo Nordisk: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity’s Board of Directors or advisory committees; Biogen Idec: Research Funding. Brown:Novo Nordisk, Biogen Idec, Baxter: Membership on an entity’s Board of Directors or advisory committees. Valentino:Baxter, Bayer, Biogen Idec, GTC Biotherapeutics, Inspiration Biopharmaceuticals, Novo Nordisk: Consultancy, Membership on an entity’s Board of Directors or advisory committees. Liesner:Bayer, Baxter, Novo Nordisk, Pfizer: Consultancy, Sponsorship Other; Octapharma: Consultancy, Research Funding, Sponsorship, Sponsorship Other; Inspiration Biopharmaceuticals: Research Funding. Dong:Biogen Idec: Employment, Equity Ownership. Diao:Biogen Idec: Employment, Equity Ownership. Jiang:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Nugent:Biogen Idec: Employment, Equity Ownership. Pierce:Biogen Idec: Employment, Equity Ownership. Allen:Biogen Idec: Employment, Equity Ownership.

Download Full-text

An Evaluation of Safety with an Extended Half-Life, Pegylated, Full-Length Recombinant Factor VIII (BAX 855) in the Treatment of 243 Patients with Hemophilia a

Blood ◽

10.1182/blood.v128.22.3801.3801 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3801-3801

Author(s):

Werner Engl ◽

Lisa Patrone ◽

Dyck-Jones Jacqueline ◽

Srilatha D. Tangada ◽

Brigitt E. Abbuehl

Keyword(s):

Factor Viii ◽

Safety Profile ◽

Half Life ◽

Perioperative Management ◽

Hemophilia A ◽

Recombinant Factor Viii ◽

Employment Equity ◽

Equity Ownership ◽

Inhibitory Antibodies

Abstract BAX 855 is an extended half-life, pegylated full-length recombinant factor VIII (PEG-rFVIII) built on ADVATE and is approved for prophylaxis and the treatment of bleeding in hemophilia A. Safety data from 7 clinical studies were integrated to evaluate single, short-term, and long-term exposure with BAX 855. These clinical trials included the following patients: previously treated adult, adolescent, and pediatric patients (PTPs) and previously untreated patients (PUPs). Immunogenicity, adverse events (AEs), and clinical laboratory parameters were assessed during prophylaxis, treatment of bleeding, perioperative management, and PK evaluations. Of 243 patients, the mean ±SD (range) age was 23.4 ±15.84 (0-61) years, there was 1 female; 74.9% of patients were White, 21.4% were Asian, and 2.5% were Black. Overall, 97 million IUs of BAX 855 were infused, resulting in a median (Q1; Q3) of 111 (73-196) exposure days (EDs) per patient, which ranged from 1 to 322 EDs. No patient developed inhibitory antibodies to FVIII (≥0.6BU) at any time. The 95% confidence intervals for developing inhibitory antibodies based on exposure are as follows: 0-0.19 for 191 PTPs with ≥50 EDs, 0-0.027 for 135 patients with ≥100 EDs, 0-0.37 for 98 patients with ≥150 EDs, and 0-0.68 for 52 patients with ≥200 EDs. At the time of the last blood sample analyzed, no patient had any antibodies to CHO proteins or persistent binding antibodies to FVIII, PEG-FVIII, or PEG. Binding antibodies were either pre-existing (28 patients) or transient (13 patients). No conclusion can be drawn as yet for 5 patients who developed binding antibodies shortly before or at the data cut-off for the analysis. The presence of binding antibodies could not be correlated to an altered PK or impaired efficacy. The only AE considered related to BAX 855 occurring in ≥1% of patients was headache; other related AEs (nausea; diarrhea, flushing, rash, and hypersensitivity) were observed in <1% of patients. No SAEs related to the use of BAX 855 were reported. One PUP discontinued due to a treatment-related AE: a mild, non-serious AE of hypersensitivity (a rash), which resolved. In total, 819 AEs were reported in 182/243 subjects administered ≥1 BAX 855 infusion. The overall rate of AEs/infusion was 2.7% (819 AEs/30,865 infusions), for non-serious AEs 2.5% (773 AEs/30,865), and for serious AEs 0.1% (46/30,865). No trends were observed in laboratory parameters or in vital signs. This safety update for BAX 855 confirms that the safety profile of BAX 855 is consistent with the safety profile of ADVATE. Overall, short- and long-term treatment with BAX 855 was safe and well tolerated in 243 pediatric, adolescent and adult subjects with severe hemophilia A from 3 completed and 4 ongoing studies. As experience with BAX 855 grows, this integrated safety update continues to confirm the safe use of BAX 855 for prophylaxis, the treatment of bleeding episodes, and perioperative management. Disclosures Engl: Shire, formerly Baxalta and Baxter: Employment, Equity Ownership. Patrone:Shire, formerly Baxalta and Baxter: Employment, Equity Ownership. Jacqueline:Baxalta US Inc., now part of Shire: Employment, Equity Ownership. Tangada:Baxalta US Inc., now part of Shire: Employment, Equity Ownership. Abbuehl:Shire, formerly Baxalta and Baxter: Employment, Equity Ownership.

Download Full-text

Target Joint Status in Patients with Hemophilia a during 18 Consecutive Months of Prophylaxis with a Pegylated Full-Length Recombinant Factor VIII with Extended Half-Life

Blood ◽

10.1182/blood.v128.22.2592.2592 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2592-2592

Author(s):

Werner Engl ◽

Lisa Patrone ◽

Brigitt E. Abbuehl

Keyword(s):

Factor Viii ◽

Treatment Period ◽

Half Life ◽

Hemophilia A ◽

Full Length ◽

Adult Patients ◽

Recombinant Factor Viii ◽

Severe Hemophilia ◽

Employment Equity ◽

Equity Ownership

Abstract Introduction and Objective: Patients with severe hemophilia A repeatedly bleed into joints and subsequently develop target joints and arthropathy. BAX 855, a polyethylene glycol pegylated, full-length, recombinant factor VIII built on ADVATE, demonstrates an extended half-life, efficacy, and safety for prophylaxis and the treatment of bleeding in patients with severe hemophilia A. Target joint status was evaluated in an ad-hocanalysis of integrated efficacy data from previously treated adolescent and adult patients who participated in the pivotal (completed) and continuation (ongoing) studies. Methods: The number of target joints, defined as a single joint with ≥3 spontaneous bleeding episodes in any consecutive 6-month period, were analyzed over 3 consecutive 6-month periods in patients who received twice weekly BAX 855 prophylaxis at 40-50 IU/kg. Results: After approximately 6 months of twice weekly prophylaxis during the pivotal study, 101 adolescent and adult patients continued treatment in the continuation study, 51 of whom were treated with twice weekly prophylaxis for 18 consecutive months. At screening 29.4% (15/51) of these patients had no target joints, 19.6% (10) had 1 target joint, 21.6% (11) had 2, and the remaining 29.4% (15) had 3 or more. After the first 6-month treatment period, the percent of patients with no target joints increased to 66.7% (34 patients), including 19 patients in whom 1 or more target joints had resolved and 15 patients who remained target joint-free from screening. Of note, for the 15 patients with 3 or more target joints at screening, all of their target joints resolved after the first 6 months of treatment with BAX 855. This trend was maintained after the second 6-month treatment period. After the third 6-month period of twice weekly prophylaxis, the percent of patients with no target joints further increased to 82.4% (42), which included the 15 patients who remained target joint-free from screening. Nine patients had 1 or more unresolved target joint after 18 months of twice weekly prophylaxis, and in 6 of these patients, 1 to 3 other target joints had resolved. Overall, there were 89 target joints at screening which reduced to 14 after 18 months of twice weekly prophylaxis. Of those, 10 target joints changed status (eg, were present, resolved, and then re-appeared) and only 4 target joints (in 4 patients) persisted as unresolved through each of the 3 consecutive 6-month treatment periods. Conclusions: These results demonstrate the efficacy of continuous twice weekly prophylaxis with BAX 855 for preventing and resolving the majority of target joints. Disclosures Engl: Shire, formerly Baxalta and Baxter: Employment, Equity Ownership. Patrone:Shire, formerly Baxalta and Baxter: Employment, Equity Ownership. Abbuehl:Shire, formerly Baxalta and Baxter: Employment, Equity Ownership.

Download Full-text

An Integrated Analysis of Long Term Safety of an Extended Half-Life, Pegylated, Full-Length Recombinant Factor VIII (BAX 855) in the Treatment of Hemophilia a

Blood ◽

10.1182/blood.v126.23.3522.3522 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3522-3522

Author(s):

Pratima Chowdary ◽

Barbara Konkle ◽

Tadashi Matsushita ◽

Werner Engl ◽

Lisa Patrone ◽

...

Keyword(s):

Adverse Events ◽

Board Of Directors ◽

Half Life ◽

Research Funding ◽

Hemophilia A ◽

Vital Signs ◽

Integrated Analysis ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership

Abstract BAX 855 is a pegylated, full-length, recombinant factor VIII (PEG rFVIII) built on ADVATE with an extended half-life that is in development for prophylaxis and treatment of bleeding in patients with hemophilia A. This safety evaluation was derived from an integrated analysis of 5 clinical studies in previously treated patients (PTPs) who were treated with BAX 855 for prophylaxis, bleeding episodes, or perioperative management, or who received a single-dose for a pharmakokinetic (PK) evaluation. Two studies have been completed (pivotal phase 2/3 and phase 1) and 3 are ongoing (continuation, surgery, and pediatric). In all studies, adverse events (AEs) (including hematology and clinical chemistry laboratory values deemed AEs by the investigator) and immunogenicity (inhibitory and binding antibodies) were assessed. Shifts in laboratory values to clinically abnormal over the course of the study and changes in pre- and post-infusion vital signs were also assessed. Of the 169 unique patients (most participated in more than 1 study), 3 were <6 years of age, 1 was 6 to <12, 25 were 12 to <18, and 140 were ≥18. The mean (SD) age was 30.1 (13.0) years and all were male. Overall, 133 (78.7%) patients were White, 34 (20.1%) were Asian, 1 (0.6%) was Black, and 1 (0.6%) was "other". These 169 patients received nearly 46 million IUs of BAX 855; 117 patients started treatment in the pivotal study and transitioned to the continuation study, for an overall median (Q1;Q3) exposure of 96 (48.0;110) days. A total of 300 AEs were reported in 96 of 169 patients during or after treatment with at least 1 infusion of BAX 855. The overall rate of AEs by infusion was 2.2% (300 AEs/13,579 infusions), the rate of nonserious AEs by infusion was 2.1% (283 AEs/13,579 infusions), and the rate of SAEs by infusion was 0.1% (16 SAEs/13,579 infusions). Common AEs considered related to BAX 855 (in ≥1% of patients) were headache and nausea; diarrhea, flushing, and blood pressure increase occurred once in 1 patient each. None of the 16 SAEs reported were considered related to the use of BAX 855. No treated patient has discontinued from a study due to a treatment related AE (or SAE). None of the patients exposed to BAX 855 developed an inhibitory antibody to FVIII of ≥0.6 BU/mL by the Bethesda assay, including 120 patients with ≥50 EDs (95% CI: 0.000 to 0.030) and 48 with ≥100 EDs (95% CI: 0.000 to 0.074). None of the 169 treated patients developed a persistent binding antibody against FVIII, PEG-FVIII, PEG, or CHO protein. Pre-existing and transient binding antibodies were detected in 21 patients; however, these were not detectable at subsequent visits or at completion of the study and appeared to have no apparent impact on efficacy or temporal association with an AE. No remarkable trends were observed in changes in laboratory parameters from baseline to last study visit or in vital signs evaluated pre- and post-infusions given at the study site (eg, PK assessments). From this integrated analysis, BAX 855 was safe and well tolerated in 169 PTPs with severe hemophilia A. The common adverse events considered related to BAX 855 treatment were consistent with the safety profile of ADVATE. Disclosures Chowdary: Sobi: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding. Konkle:Baxalta: Consultancy, Research Funding; CSL Behring: Consultancy; Pfizer: Consultancy; Novo Nordisk: Consultancy; Octapharma: Research Funding; Biogen: Consultancy, Research Funding. Matsushita:Baxalta: Research Funding. Engl:Baxalta: Employment, Equity Ownership. Patrone:Baxalta: Employment, Equity Ownership. Abbuehl:Baxalta: Employment, Equity Ownership.

Download Full-text

Phase I, Randomized, Double-Blind, Placebo-Controlled, Single-Dose Escalation Study of the rFVIIa Variant (BAY 86–6150) In Hemophilia A or B with or without Inhibitors.

Blood ◽

10.1182/blood.v116.21.3679.3679 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3679-3679 ◽

Cited By ~ 1

Author(s):

J.N. Mahlangu ◽

M.J. Coetzee ◽

M. Laffan ◽

J. Windyga ◽

T. T. Yee ◽

...

Keyword(s):

Board Of Directors ◽

Half Life ◽

Research Funding ◽

Hemophilia A ◽

Employment Equity ◽

Advisory Committees ◽

Dose Escalation Study ◽

Double Blind ◽

Bleeding Episodes ◽

Equity Ownership

Abstract Abstract 3679 Bleeding episodes in hemophilia A or B patients with inhibitors to factors VIII or IX are commonly managed with bypassing agents such as recombinant factor VIIa (rFVIIa). However, currently available rFVIIa treatment is associated with variable response rates and a short elimination half-life, often necessitating the administration of multiple doses to control bleeding. BAY 86–6150, a human rFVIIa variant, was developed to provide a longer-acting and more potent activated factor VII in the management of bleeding episodes in patients with hemophilia who developed inhibitors. The safety, tolerability, pharmacodynamic/pharmacokinetic (PD/PK) profiles, and immunogenicity of BAY 86–6150 in nonbleeding patients with hemophilia was investigated in a phase I, randomized, double-blind, placebo-controlled, single-dose escalation study. The patient population comprised nonbleeding men aged 18–65 years with moderate or severe hemophilia A or B with or without inhibitors. 16 patients were randomized 3:1 to escalating doses of BAY 86–6150 at 6.5, 20, 50, or 90 μg/kg (n=3 each) or placebo (n=4). Patients were followed for 50 days postdose. The objective of the trial was to evaluate the safety and tolerability of BAY 86–6150, with adverse events (AEs) as the primary endpoint. Other endpoints included PK parameters, the effects of BAY 86–6150 on hemostasis markers and coagulation, and the immunogenicity of the compound. BAY 86–6150 was not associated with clinically significant AEs or dose-limiting toxicities and the PK parameters were linear over the dose range, with a half-life of 5–7 hours. Patients demonstrated consistent, dose-dependent thrombin generation ex-vivo in platelet-poor plasma (mean peak effect 26–237 nM thrombin from 6.5–90 μg/kg). Peak thrombin levels over time paralleled the presence of BAY 86–6150 by PK analysis, indicating that the drug in circulation retained activity. There were corresponding decreases in time and duration in the activated partial thromboplastin and prothrombin time testing. In contrast, there was no dose response seen in the thrombogenicity markers evaluated including antithrombin III, prothrombin fragment 1+2, TAT, and D-dimer. One patient demonstrated antibody activity to both BAY 86–6150 and to rVIIa as determined by ELISA testing at baseline. The level of inhibition and titer remained constant when evaluated in follow-up on day 29 and day 49. The data safety monitoring board recommended progression to the highest proposed dose (90 μg/kg). The phase II/III studies are designed to evaluate the clinical efficacy and safety as well as corresponding laboratory markers. Results of the present study suggest that the novel rFVIIa agent BAY 86–6150 is safe and has increased potency and a longer half-life compared with the currently available rFVIIa therapy. BAY 86–6150 may therefore have the potential to improve the treatment of bleeding episodes in hemophilic patients with inhibitors. Disclosures: Mahlangu: Bayer Helathcare: Consultancy, Honoraria, Speakers Bureau; NovoNordisk: Consultancy, Honoraria, Speakers Bureau; IAVI: Consultancy; Maxygen: Consultancy. Coetzee:Bayer Schering Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Laffan:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; NovoNordisk: Membership on an entity's Board of Directors or advisory committees. Windyga:Bayer HealthCare Pharmaceuticals: Research Funding; Bayer, Baxter, Behring, NovoNordisk, Octapharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Yee:Bayer HealthCare Pharmaceuticals: Research Funding. Schroeder:Bayer Schering Pharma AG: Employment, Equity Ownership. Haaning:Bayer HealthCare Pharmaceuticals: Employment, Equity Ownership. Siegel:Bayer HealthCare Pharmaceuticals: Employment, Equity Ownership. Lemm:Bayer Schering Pharma AG: Employment, Equity Ownership.

Download Full-text

An Immunodeficient Mouse Model With Circulating Human Platelets To Evaluate The Platelet Clearance and Pharmacokinetics Of Platelet-Targeted Coagulation Factor VIIa

Blood ◽

10.1182/blood.v122.21.2345.2345 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2345-2345

Author(s):

Siyuan Tan ◽

Kai Chen ◽

Joe Salas ◽

Robert Peters ◽

David R. Light ◽

...

Keyword(s):

Half Life ◽

Hemophilia A ◽

Human Platelet ◽

Human Platelets ◽

Employment Equity ◽

In Vivo Models ◽

Nsg Mice ◽

Equity Ownership

Abstract Treatment of bleeding episodes in hemophilia patients with inhibitory antibodies to factor VIII or factor IX by recombinant activated factor VII (rFVIIa, NovoSeven) has been sub-optimal partly due to its low affinity to activated platelets and its short half-life in circulation. To develop a rFVIIa variant with enhanced coagulant activity, we have targeted rFVIIa to platelets by monoclonal antibodies that recognize the human platelet receptor αIIbβ3. However, the assessment of pharmacokinetic parameters in mice is limited by the lack of recognition of mouse αIIbβ3 by antibodies to human αIIbβ3. The present study addresses the need to develop appropriate in vivo models to study this new class of bypass therapeutics. First, we evaluated the survival of human platelets in hemophilia A, NOD/SCID, and NOD/SCID/gamma (NSG) mice. Platelet concentrates were prepared from normal human donors and transfused retro-orbitally into mice. The whole blood from dosed mice was then collected via tail vein laceration at various times and the human platelet counts in blood was determined by flow cytometry after staining with fluorescently labeled antibodies against human CD42b, mouse CD61, human FVII to visualize the human platelets, mouse platelets, and the FVIIa candidate that bound to human platelets, respectively. The half-life of human platelets in NOD/scid/gamma (NSG) mice was approximately 4 hours, which is considerably longer than the 0.8 hour half-life observed in hemophilia A mice. The effect of platelet-targeted FVIIa variants on the clearance of human platelets was then investigated in NSG mice. The FVIIa candidates were pre-selected for their inactivity toward human platelet activation and aggregation, as determined in a battery of in vitro assays. In agreement with the in vitro results, all of these selected candidates did not affect the clearance of the transfused human platelets when dosed in NSG mice at 5 nmol/kg. In contrast, a control antibody fusion protein that is known to activate platelets and cause thrombocytopenia in vivo led to rapid platelet clearance in NSG mice. Similar results were observed for these proteins in cynomolgous monkeys when dosed at 2 nmol/kg. The NSG mice with circulating human platelets were also explored to evaluate the clearance of FVIIa candidates that remain platelet-associated in vivo. To improve the pharmacokinetics, we have fused XTEN, a hydrophilic peptide that increases the dynamic radius of payload proteins, to the platelet-targeted FVIIa candidates. When tested in NSG mice model for the clearance of platelet-associated protein, addition of XTEN markedly reduced the clearance rate, resulting in several fold increase in exposure. Together these data indicate that NSG mice with circulating human platelets can be used to assess the safety and pharmacokinetics of the platelet-targeted FVIIa variants, and the method can be adapted to evaluate other agents designed to utilize platelet-targeting approaches. Disclosures: Tan: Biogen Idec: Employment, Equity Ownership. Chen:Biogen Idec: Employment, Equity Ownership. Salas:Biogen Idec: Employment, Equity Ownership. Peters:Biogen Idec: Employment, Equity Ownership. Light:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Jiang:Biogen Idec: Employment; Biogen Idec: Equity Ownership.

Download Full-text

Enhancing the Acute Hemostatic Efficacy in Cynomolgus Monkeys By Targeting Activated Coagulation Factor VII to Platelets

Blood ◽

10.1182/blood.v124.21.1488.1488 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1488-1488

Author(s):

Siyuan Tan ◽

Joe Salas ◽

Kai Chen ◽

Tamera Ashworth ◽

Sarah Smith ◽

...

Keyword(s):

Flow Cytometry ◽

Whole Blood ◽

Half Life ◽

Hemophilia A ◽

Factor Vii ◽

Employment Equity ◽

Cynomolgus Monkeys ◽

Hemostatic Activity ◽

Equity Ownership ◽

Inhibitory Antibodies

Abstract Recombinant activated factor VII (rFVIIa) is used for controlling bleeds in hemophilia A and B patients with inhibitory antibodies against factor VIII or factor IX. The hemostatic effect of rFVIIa at pharmacological doses is believed to be mediated by activating the tenase complex on platelets directly at the site of injury to promote thrombin generation. To increase the hemostatic activity of rFVIIa, we sought to target rFVIIa to platelets by fusing a single chain variable region of a monoclonal antibody against human platelet receptor αIIbβ3. The resulting fusion protein, FVII-189, displays higher affinity to human platelets and about 50-fold higher hemostatic activity than that of rFVIIa in whole blood from hemophilia A patients by rotational thromboelastometry (ROTEM). Here we investigated the safety, pharmacokinetics, and pharmacodynamics of FVII-189 in cynomolgus monkeys. First, we confirmed that FVII-189 cross-reacted to platelets from cynomolgus monkeys. When spiked in the monkey whole blood, FVII-189 could bind platelets in a dose-dependent manner, as measured by flow cytometry using fluorescently labeled antibodies against FVII, whereas platelet-binding by rFVIIa was not detectable in the same assay. More importantly, increased hemostatic activity of FVII-189 was observed by ROTEM in acquired hemophilic monkey blood where factor VIII activity was neutralized by the inhibitory antibodies. We then evaluated FVII-189 in cynomolgus monkeys following a bolus intravenous administration (n=3) at an equal molar dose to the pharmacological dose of rFVIIa (~2 nmol/kg). rFVIIa was included as a comparator. Both FVII-189 and rFVIIa appeared to be well tolerated with no abnormal clinical observations that could be attributed to the dosing. No apparent effects on platelet count in whole blood, as well as other hematology and coagulation parameters except for a temporary decrease in prothrombin time over a few hours, which was an expected pharmacological effect of rFVIIa and FVII-189. Compared to rFVIIa, FVII-189 cleared more rapidly in plasma, and distributed more to the platelets. The half-life of FVII-189 antigen on platelets was found to be several fold longer than that of rFVIIa antigen in plasma, as measured by ELISA of the platelet-rich plasma, or by flow cytometry of platelet-associated FVII-189 antigen. Despite the lower initial recovery and faster clearance of FVII-189 in plasma, directing FVII-189 to platelets resulted in much higher hemostatic activity of the whole blood 5 minute and 1 hour after dosing, as measured by ex vivo ROTEM assay. In conclusion, these results indicate that in cynomolgus monkeys, 1) FVII-189 is safe and does not affect the platelet clearance, 2) FVII-189 protein is targeted to platelets with fast clearance in plasma and prolonged half-life on platelets and 3) FVII-189 could be more efficacious in controlling acute bleeds than rFVIIa. Disclosures Tan: Biogen Idec: Employment, Equity Ownership. Salas:Biogen Idec: Employment, Equity Ownership. Chen:Biogen Idec: Employment, Equity Ownership. Ashworth:Biogen Idec: Employment, Equity Ownership. Smith:Biogen Idec: Employment, Equity Ownership. Kistanova:Biogen Idec: Employment, Equity Ownership. Moore:Biogen Idec: Employment, Equity Ownership. Acosta:Biogen Idec: Employment, Equity Ownership. Kole:Biogen Idec: Employment, Equity Ownership. Light:Biogen Idec: Employment, Equity Ownership. Peters:Biogen Idec: Employment. Jiang:Biogen Idec: Employment, Equity Ownership.

Download Full-text