The Experts below are selected from a list of 3375 Experts worldwide ranked by ideXlab platform
Elena Santagostino - One of the best experts on this subject based on the ideXlab platform.
-
long term safety and efficacy of recombinant Coagulation Factor IX albumin fusion protein rIX fp in previously treated pediatric patients with hemophilia b results from a phase 3b extension study
Thrombosis and Haemostasis, 2020Co-Authors: Gili Kenet, Herve Chambost, Christoph Male, Thierry Lambert, Susan Halimeh, Wilfried Seifert, Elena SantagostinoAbstract:Introduction A phase 3b extension study evaluated the long-term safety and efficacy of a recombinant fusion protein-linking Coagulation Factor IX (FIX) with albumin (rIX-FP) for the routine prophylaxis and on-demand treatment of bleeding in pediatric hemophilia B patients. Methods Previously treated patients aged Results Compared with their initial regimen, by the end of the study, dosing intervals were the same, extended, and shortened in 16, 4, and 4 patients, respectively. Very low annualized spontaneous bleeding rates (AsBRs) were observed; median AsBR was 0.0 for the 7- and 10-day regimens, and 1.1 for the 14-day regimen. The 7- and 14-day regimens were comparable in preventing spontaneous bleeds; mean (95% confidence interval) difference in AsBR of −1.2 (−2.6 to 0.3) bleeding episodes/year/subject. Overall, 96% of bleeding episodes were successfully treated with one or two injections of rIX-FP. Patients on a 14-day regimen maintained a mean steady-state trough FIX level of >7.2 IU/dL. No patient developed an inhibitor. Conclusion This extension study demonstrated the long-term safety and efficacy of weekly rIX-FP in pediatric patients. Additionally, it showed that adequate bleed protection can be achieved with 10- or 14-day rIX-FP regimens in selected pediatric patients while maintaining safety.
-
transforming the treatment for hemophilia b patients update on the clinical development of recombinant fusion protein linking recombinant Coagulation Factor IX with recombinant albumin rIX fp
Thrombosis Research, 2016Co-Authors: Elena SantagostinoAbstract:Recombinant fusion protein linking recombinant Coagulation Factor IX with recombinant albumin (rIX-FP; Idelvion®(†)) is an innovative new treatment designed to extend the half-life of Factor IX (FIX) and ease the burden of care for hemophilia B patients. The rIX-FP clinical development program - PROLONG-9FP - is in its advanced phases, with pivotal studies in previously treated adults, adolescents, and pediatrics now completed. Across all age groups studied, rIX-FP has demonstrated a markedly improved pharmacokinetic profile compared with plasma-derived and recombinant FIX treatments, with a 30-40% higher incremental recovery, an approximately 5-fold longer half-life, a lower clearance, and a greater area under the curve. rIX-FP has been very well tolerated with an excellent safety profile. In the pivotal studies, there have been no reports of FIX inhibitors or antidrug antibodies, and few treatment-related adverse events have been observed. Prophylactic regimens of rIX-FP administered once weekly to once every 14 days have been highly effective. When used for surgical prophylaxis, a single infusion of rIX-FP has been sufficient to maintain hemostasis, even during major orthopedic surgery. An ongoing study is now enrolling previously untreated patients and evaluating the possibility of extending the dosing interval to every 21 days. There is little doubt that rIX-FP will transform the treatment of hemophilia B.
-
long acting recombinant Coagulation Factor IX albumin fusion protein rIX fp in hemophilia b results of a phase 3 trial
Blood, 2016Co-Authors: Elena Santagostino, Johannes Oldenburg, Claude Negrier, Uri Martinowitz, Toshko Lissitchkov, Brigitte Panpetesch, Hideji Hanabusa, Lisa N Boggio, Ingrid Pabinger, Mario Von Depka ProndzinskiAbstract:A global phase 3 study evaluated the pharmacokinetics, efficacy, and safety of recombinant fusion protein linking Coagulation Factor IX with albumin (rIX-FP) in 63 previously treated male patients (12-61 years) with severe hemophilia B (Factor IX [FIX] activity ≤2%). The study included 2 groups: group 1 patients received routine prophylaxis once every 7 days for 26 weeks, followed by either 7-, 10-, or 14-day prophylaxis regimen for a mean of 50, 38, or 51 weeks, respectively; group 2 patients received on-demand treatment of bleeding episodes for 26 weeks and then switched to a 7-day prophylaxis regimen for a mean of 45 weeks. The mean terminal half-life of rIX-FP was 102 hours, 4.3-fold longer than previous FIX treatment. Patients maintained a mean trough of 20 and 12 IU/dL FIX activity on prophylaxis with rIX-FP 40 IU/kg weekly and 75 IU/kg every 2 weeks, respectively. There was 100% reduction in median annualized spontaneous bleeding rate (AsBR) and 100% resolution of target joints when subjects switched from on-demand to prophylaxis treatment with rIX-FP (P< .0001). The median AsBR was 0.00 for all prophylaxis regimens. Overall, 98.6% of bleeding episodes were treated successfully, including 93.6% that were treated with a single injection. No patient developed an inhibitor, and no safety concerns were identified. These results indicate rIX-FP is safe and effective for preventing and treating bleeding episodes in patients with hemophilia B at dosing regimens of 40 IU/kg weekly and 75 IU/kg every 2 weeks. This trial was registered at www.clinicaltrials.gov as #NCT0101496274.
-
pharmacokinetic results of two phase iii clinical studies of Coagulation Factor IX recombinant albumin fusion protein rIX fp in previously treated patients with hemophilia b prolong 9fp
Blood, 2014Co-Authors: Elena Santagostino, Christine Voigt, Iris Jacobs, Annettee Feussner, Tharin LimsakunAbstract:A recombinant fusion protein linking recombinant Coagulation Factor IX (FIX) with recombinant human albumin (rIX-FP) has been developed to extend the plasma half-life of FIX, thus improving hemophilia B treatment by allowing less frequent dosing than required with standard plasma-derived (pd) and recombinant (r) FIX products. The PROLONG-9FP clinical program aims to evaluate the use of rIX-FP for prophylaxis and on-demand treatment of bleeding in patients with severe hemophilia B. In a completed Phase I pharmacokinetic (PK) study in subjects aged 15 to 58 years (y), the mean half-life of rIX-FP was 92 hours, 5 times longer than the half-life of the FIX products previously used by the subjects. The mean trough FIX activity after injection of rIX-FP was 7.4% (day 7) at a dose of 25 IU/kg, and 13.4% (day 7) and 5.5% (day 14) at a dose of 50 IU/kg (Santagostino E, et al. Blood 2012; 120:2405-11) . A Phase II study demonstrated the efficacy of weekly prophylaxis with rIX-FP, with excellent safety and an improved PK profile. Following completion of these studies, 2 Phase III, open-label, multicenter studies have been conducted in previously treated patients (PTPs) with severe hemophilia B, aged 12 to 65 years ([NCT01496274][1]) and < 12 years ([NCT01662531][2]). Both studies, which were designed to evaluate the long term safety and efficacy of rIX-FP for both prophylaxis and on-demand treatment of bleeding episodes, consisted of an initial PK evaluation period followed by a treatment period during which subjects were administered rIX-FP as prophylaxis and on-demand treatment. Subjects from 42 hemophilia treatment centers in 12 countries participated; to date, the PROLONG-9FP clinical program encompasses over 100 hemophilia B subjects for the PK evaluation. Here, we report on the PK results from these 2 studies. During the 14-day PK evaluation periods, blood samples for PK analysis were taken before dosing, and then at 30 minutes, 3, 24, 48, 72, 120, 168, 240 and 336 hours after injection of 50 IU/kg rIX-FP. A subgroup of subjects also completed a PK evaluation of their previously used Factor IX products (pdFIX and rFIX), with sampling before dosing, and then at 30 minutes, 3, 6, 12, 24 and 48 hours after 50 IU/kg FIX injection. Plasma FIX activity (FIX:C) was measured by a one-stage clotting assay (CSL Behring central laboratory). The mean plasma FIX half-life after injection of 50 IU/kg rIX-FP was 105, 92 and 84 hours in the respective age groups of 12 to 61 years (n = 46), 6 to 11 years (n = 15) and 1 to 5 years (n = 12); the baseline corrected mean incremental recovery (IR) was 1.3, 1.1 and 1.0 IU/dL per IU/kg, the mean area under the curve (AUC) was 7,360, 4,949 and 4,358 IU*hr/dL, and the clearance was 0.7, 1.1 and 1.3 mL/h/kg in the respective age groups. The time to 5% FIX:C after injection of 50 IU/kg rIX-FP administration was Day 10 for children and Day 14 for adults; at Day 14, the mean trough FIX activity in children was 3%. Compared with the FIX products previously used by the subjects, rIX-FP had a 30 to 40% higher incremental recovery, > 5-times longer half-life, larger AUC and lower clearance. In conclusion, compared with standard FIX products, rIX-FP demonstrated an improved PK profile with a prolonged half-life in all age groups (1 to 61 years). At 14 days after injection of rIX-FP, the mean trough FIX activity is 3% in children and above 5% in adults, supporting a treatment interval of 14 days for routine prophylaxis. Treatment intervals of 7-, 10- and 14 days for routine prophylaxis were tested in the pivotal Phase III studies; every 21 day regimen will be tested in selected age groups during the Phase IIIb extension study. Detailed PK results will be presented during the meeting. Disclosures Santagostino: CSL: Honoraria, Speakers Bureau. Jacobs: CSL Behring: Employment. Voigt: Csl Behring: Employment. Feussner: CSL Behring: Employment. Limsakun: CSL Behring: Employment. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01496274&atom=%2Fbloodjournal%2F124%2F21%2F1491.atom [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01662531&atom=%2Fbloodjournal%2F124%2F21%2F1491.atom
-
prolong 9fp clinical development program phase i results of recombinant fusion protein linking Coagulation Factor IX with recombinant albumin rIX fp
Thrombosis Research, 2013Co-Authors: Elena SantagostinoAbstract:Abstract Hemophilia B is a severe bleeding disorder that is characterized by a deficiency or dysfunction of Coagulation Factor IX (FIX). Replacement therapy using recombinant or plasma-derived FIX is available, but the relatively short half-life of FIX (approximately 18 hours) necessitates administration every 2–3 days to prevent bleeding episodes. A recombinant fusion protein linking Coagulation Factor IX with albumin, known as rIX-FP, was developed to extend the half-life of recombinant FIX and allow for less frequent dosing. In a phase I, multicenter, dose-escalation trial ( PROLONG-9FP ), the safety and pharmacokinetics of rIX-FP were assessed in patients with hemophilia B. At a dose of 25–75 IU/kg, rIX-FP was well tolerated: no serious adverse events were reported and there was no evidence of hypersensitivity or immunogenic reactions. Pharmacokinetic analysis indicated enhanced properties, including a 5-fold increase in half-life, 44% higher recovery, 7-fold greater area under the curve, and 7-fold slower clearance, compared with recombinant FIX. Trough levels were maintained above 5% after 7 days when rIX-FP was administered at 25 IU/kg and after 14 days when given at 50 IU/kg, suggesting that schedules involving weekly dosing or dosing every 2 weeks are feasible. These results represent the first reported experience with rIX-FP in humans, and suggest that rIX-FP therapy is feasible and well tolerated in patients with hemophilia B. Phase II/III studies evaluating rIX-FP are underway.
Christine Voigt - One of the best experts on this subject based on the ideXlab platform.
-
population pharmacokinetics of a new long acting recombinant Coagulation Factor IX albumin fusion protein for patients with severe hemophilia b
Journal of Thrombosis and Haemostasis, 2016Co-Authors: Ying Zhang, Christine Voigt, Iris Jacobs, Massimo Morfini, John Roberts, Debra M Bensenkennedy, E Santagostino, Annette Feussner, Jagdev SidhuAbstract:Essentials The new recombinant Factor IX (FIX) albumin fusion protein (rIX-FP) has a prolonged half-life. A population pharmacokinetic (PK) model was based on FIX activity levels of hemophilia B patients. The model was used to simulate different dosing scenarios of rIX-FP to help guide dosing. The population PK model supported prolonged dosing of rIX-FP with intervals of up to 2 weeks. Click to hear Prof.Makris's presentation on new treatments in hemophilia SUMMARY: Background The recombinant fusion protein linking recombinant Coagulation Factor IX with recombinant albumin (rIX-FP; Idelvion® ) exhibits a longer half-life than plasma-derived Factor IX (FIX) and the commercially available recombinant FIX products. Objectives (i) Characterize the population pharmacokinetics (PK) of rIX-FP in hemophilia B patients, (ii) identify covariates that are potential determinants of rIX-FP PK variability and (iii) simulate different dosing scenarios of rIX-FP following single and steady-state dosing. Patients/Methods A population PK model was developed based on FIX activity levels of 104 patients who had received treatment with rIX-FP. Patients were aged 1-65 years with FIX activity ≤ 2 IU dL-1 . PK sampling was performed for up to 14 days (336 h). Results Simulation of a single intravenous infusion of rIX-FP (25-75 IU kg-1 ) predicted that the median trough exogenous FIX activity levels would remain > 5 IU dL-1 for up to 16 days in adolescents/adults aged ≥ 12 years, up to 12 days in children aged 6 to 5 IU dL-1 for the duration of the dosing interval for the 25, 35 and 40 IU kg-1 weekly regimens and for 75 IU kg-1 every 14 days in adolescents/adults, and for the 35 and 40 IU kg-1 weekly regimens in children. Conclusion The population PK model developed here correlates well with observed clinical data and supports prolonged dosing of rIX-FP with intervals of up to 2 weeks.
-
long acting recombinant fusion protein linking Coagulation Factor IX with albumin rIX fp in children results of a phase 3 trial
Thrombosis and Haemostasis, 2016Co-Authors: Gili Kenet, Herve Chambost, Christoph Male, Thierry Lambert, Susan Halimeh, Tatiana Chernova, Maria Elisa Mancuso, Julie Curtin, Christine VoigtAbstract:A global phase 3 study evaluated the pharmacokinetics, efficacy and safety of a recombinant fusion protein linking Coagulation Factor IX with albumin (rIX-FP) in 27 previously treated male children (1–11 years) with severe and moderately severe haemophilia B (Factor IX [FIX] activity ≤2 IU/dl). All patients received routine prophylaxis once every seven days for up to 77 weeks, and treated any bleeding episodes on-demand. The mean terminal half-life of rIX-FP was 91.4 hours (h), 4.3-fold longer than previous FIX treatment and clearance was 1.11 ml/h/kg, 6.4-fold slower than previous FIX treatment. The median (Q1, Q3) annualised spontaneous bleeding rate was 0.00 (0.00, 0.91) and was similar between the
-
results of a phase i ii open label safety and efficacy trial of Coagulation Factor IX recombinant albumin fusion protein in haemophilia b patients
Haemophilia, 2015Co-Authors: Uri Martinowitz, Christine Voigt, Iris Jacobs, Toshko Lissitchkov, Aaron Lubetsky, G Jotov, Tami Barazanibrutman, T Wuerfel, E SantagostinoAbstract:Introduction rIX-FP is a Coagulation Factor IX (recombinant), albumin fusion protein with more than fivefold half-life prolongation over other standard Factor IX (FIX) products available on the market. Aim This prospective phase II, open-label study evaluated the safety and efficacy of rIX-FP for the prevention of bleeding episodes during weekly prophylaxis and assessed the haemostatic efficacy for on-demand treatment of bleeding episodes in previously treated patients with haemophilia B. Methods The study consisted of a 10–14 day evaluation of rIX-FP pharmacokinetics (PK), and an 11 month safety and efficacy evaluation period with subjects receiving weekly prophylaxis treatment. Safety was evaluated by the occurrence of related adverse events, and immunogenic events, including development of inhibitors. Efficacy was evaluated by annualized spontaneous bleeding rate (AsBR), and the number of injections to achieve haemostasis. Results Seventeen subjects participated in the study, 13 received weekly prophylaxis and 4 received episodic treatment only. No inhibitors were detected in any subject. The mean and median AsBR were 1.25, and 1.13 respectively in the weekly prophylaxis arm. All bleeding episodes were treated with 1 or 2 injections of rIX-FP. Three prophylaxis subjects who were treated on demand prior to study entry had >85% reduction in AsBR compared to the bleeding rate prior to study entry. Conclusion This study demonstrated the efficacy for weekly routine prophylaxis of rIX-FP to prevent spontaneous bleeding episodes and for the treatment of bleeding episodes. In addition no safety issues were detected during the study and an improved PK profile was demonstrated.
-
pharmacokinetic results of two phase iii clinical studies of Coagulation Factor IX recombinant albumin fusion protein rIX fp in previously treated patients with hemophilia b prolong 9fp
Blood, 2014Co-Authors: Elena Santagostino, Christine Voigt, Iris Jacobs, Annettee Feussner, Tharin LimsakunAbstract:A recombinant fusion protein linking recombinant Coagulation Factor IX (FIX) with recombinant human albumin (rIX-FP) has been developed to extend the plasma half-life of FIX, thus improving hemophilia B treatment by allowing less frequent dosing than required with standard plasma-derived (pd) and recombinant (r) FIX products. The PROLONG-9FP clinical program aims to evaluate the use of rIX-FP for prophylaxis and on-demand treatment of bleeding in patients with severe hemophilia B. In a completed Phase I pharmacokinetic (PK) study in subjects aged 15 to 58 years (y), the mean half-life of rIX-FP was 92 hours, 5 times longer than the half-life of the FIX products previously used by the subjects. The mean trough FIX activity after injection of rIX-FP was 7.4% (day 7) at a dose of 25 IU/kg, and 13.4% (day 7) and 5.5% (day 14) at a dose of 50 IU/kg (Santagostino E, et al. Blood 2012; 120:2405-11) . A Phase II study demonstrated the efficacy of weekly prophylaxis with rIX-FP, with excellent safety and an improved PK profile. Following completion of these studies, 2 Phase III, open-label, multicenter studies have been conducted in previously treated patients (PTPs) with severe hemophilia B, aged 12 to 65 years ([NCT01496274][1]) and < 12 years ([NCT01662531][2]). Both studies, which were designed to evaluate the long term safety and efficacy of rIX-FP for both prophylaxis and on-demand treatment of bleeding episodes, consisted of an initial PK evaluation period followed by a treatment period during which subjects were administered rIX-FP as prophylaxis and on-demand treatment. Subjects from 42 hemophilia treatment centers in 12 countries participated; to date, the PROLONG-9FP clinical program encompasses over 100 hemophilia B subjects for the PK evaluation. Here, we report on the PK results from these 2 studies. During the 14-day PK evaluation periods, blood samples for PK analysis were taken before dosing, and then at 30 minutes, 3, 24, 48, 72, 120, 168, 240 and 336 hours after injection of 50 IU/kg rIX-FP. A subgroup of subjects also completed a PK evaluation of their previously used Factor IX products (pdFIX and rFIX), with sampling before dosing, and then at 30 minutes, 3, 6, 12, 24 and 48 hours after 50 IU/kg FIX injection. Plasma FIX activity (FIX:C) was measured by a one-stage clotting assay (CSL Behring central laboratory). The mean plasma FIX half-life after injection of 50 IU/kg rIX-FP was 105, 92 and 84 hours in the respective age groups of 12 to 61 years (n = 46), 6 to 11 years (n = 15) and 1 to 5 years (n = 12); the baseline corrected mean incremental recovery (IR) was 1.3, 1.1 and 1.0 IU/dL per IU/kg, the mean area under the curve (AUC) was 7,360, 4,949 and 4,358 IU*hr/dL, and the clearance was 0.7, 1.1 and 1.3 mL/h/kg in the respective age groups. The time to 5% FIX:C after injection of 50 IU/kg rIX-FP administration was Day 10 for children and Day 14 for adults; at Day 14, the mean trough FIX activity in children was 3%. Compared with the FIX products previously used by the subjects, rIX-FP had a 30 to 40% higher incremental recovery, > 5-times longer half-life, larger AUC and lower clearance. In conclusion, compared with standard FIX products, rIX-FP demonstrated an improved PK profile with a prolonged half-life in all age groups (1 to 61 years). At 14 days after injection of rIX-FP, the mean trough FIX activity is 3% in children and above 5% in adults, supporting a treatment interval of 14 days for routine prophylaxis. Treatment intervals of 7-, 10- and 14 days for routine prophylaxis were tested in the pivotal Phase III studies; every 21 day regimen will be tested in selected age groups during the Phase IIIb extension study. Detailed PK results will be presented during the meeting. Disclosures Santagostino: CSL: Honoraria, Speakers Bureau. Jacobs: CSL Behring: Employment. Voigt: Csl Behring: Employment. Feussner: CSL Behring: Employment. Limsakun: CSL Behring: Employment. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01496274&atom=%2Fbloodjournal%2F124%2F21%2F1491.atom [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01662531&atom=%2Fbloodjournal%2F124%2F21%2F1491.atom
-
safety and pharmacokinetics of a novel recombinant fusion protein linking Coagulation Factor IX with albumin rIX fp in hemophilia b patients
Blood, 2012Co-Authors: Elena Santagostino, Christine Voigt, Claude Negrier, R Klamroth, Andreas Tiede, Ingrid Pabingerfasching, Iris Jacobs, Massimo MorfiniAbstract:A recombinant fusion protein linking Coagulation Factor IX (FIX) with human albumin (rIX-FP) has been developed to facilitate hemophilia B treatment by less frequent FIX dosing. This first-in-human dose-escalation trial in 25 previously treated subjects with hemophilia B (FIX ≤ 2 IU/dL) examined the safety and pharmacokinetics of 25, 50, and 75 IU/kg rIX-FP. Patients in the 50-IU/kg cohort underwent a comparative pharmacokinetics assessment with their previous FIX product (plasma-derived or recombinant). No allergic reactions or inhibitors were observed. Four mild, possibly treatment-related adverse events were reported. In the 50-IU/kg cohort (13 subjects), the mean half-life of rIX-FP was 92 hours, more than 5 times longer than the subjects' previous FIX product. After 25 or 50 IU/kg rIX-FP administration, the baseline-corrected mean FIX activity remained elevated at day 7 (7.4 IU/dL and 13.4 IU/dL, respectively) and day 14 (2.5 IU/dL and 5.5 IU/dL, respectively). The incremental recovery of rIX-FP was higher than both recombinant and plasma-derived FIX (1.4 vs 0.95 and 1.1 IU/dL per IU/kg, respectively). These results demonstrated both the safety and improved pharmacokinetics of rIX-FP, thus indicating this new product with extended half-life as possibly able to control and prevent bleeding with less frequent injection.
Takashi Morita - One of the best experts on this subject based on the ideXlab platform.
-
Re-evaluation of M-LAO, L-amino acid oxidase, from the venom of Gloydius blomhoffi as an anticoagulant protein.
Journal of biochemistry, 2009Co-Authors: Daisuke Fujisawa, Yasuo Yamazaki, Takashi MoritaAbstract:Many anticoagulant proteins have been found from snake venoms. Recently, L -amino acid oxidase (LAO) from the venom of Gloydius blomhoffi, M-LAO, was reported to inhibit Coagulation Factor IX; however, the mechanism of its anticoagulant activity is still unclear. Here, we re-evaluated the anticoagulant activity of M-LAO. We first purified M-LAO from the venom of G. blomhoffi, and examined the effect of LAO inhibitors and the hydrogen peroxide scavenger, catalase, on the anticoagulant activity of M-LAO. We found that the isolated M-LAO fraction prolongs the APTT, PT and fibrinogen clotting time and cleaves the Aα-chain of fibrinogen. LAO inhibitors or catalase did not inhibit these effects. Detailed analysis revealed that the M-LAO fraction contained a small amount of 39-kDa metalloproteinase. The prolongation of clotting time and degradation of fibrinogen were inhibited by a metalloproteinase inhibitor. Therefore, we concluded that the anticoagulant activity of the M-LAO fraction was caused by the 39-kDa metalloproteinase.
-
characterization of a monoclonal antibody b1 that recognizes phosphorylated ser 158 in the activation peptide region of human Coagulation Factor IX
Journal of Biological Chemistry, 2006Co-Authors: Hideko Atoda, Emi Yokota, Takashi MoritaAbstract:Blood Coagulation Factor IX (FIX) undergoes various post-translational modifications such as gamma-carboxylation and glycosylation. Non-phosphorylated recombinant FIX has been reported to rapidly disappear from plasma, indicating that phosphorylation of FIX plays an important role in the physiological activity of this Coagulation Factor. In this study, we characterized the human FIX activation peptide (AP) using a monoclonal antibody that recognizes phosphorylated Ser-158 in the AP region. Murine monoclonal antibody B1 against human FIX recognized FIX with an apparent K(d) value of 5 nm in the presence of Ca(2+) (EC(50) = 0.58 mm). B1 bound to the isolated AP of FIX and retained the Ca(2+) dependence of binding to the isolated AP. The deglycosylation of AP did not affect the binding of B1 to AP, while B1 failed to bind to recombinant AP expressed in Escherichia coli. MALDI-TOF mass spectrometry showed that the m/z of plasma-derived deglycosylated AP is 82.54 Da greater than that of recombinant AP. The binding ability of B1 to AP was lost by the dephosphorylation of plasma-derived AP. B1 bound to synthetic peptide AP-(5-19), including phosphoserine-13, but not to the non-phosphorylated AP-(5-19) in the presence of Ca(2+). These data provide direct evidence that Ser-13 of the plasma-derived FIX AP region (Ser-158 of FIX) is phosphorylated and that B1 recognizes the epitope, which includes Ca(2+)-bound phosphoserine-158. B1 should be useful in the quality control of biologically active recombinant FIX containing phosphoserine-158.
-
crystal structure of Coagulation Factor IX binding protein from habu snake venom at 2 6 a implication of central loop swapping based on deletion in the linker region
Journal of Molecular Biology, 1999Co-Authors: Hiroshi Mizuno, Hideko Atoda, Zui Fujimoto, Mika Koizumi, Hiromi Kano, Takashi MoritaAbstract:Abstract Coagulation Factor IX-binding protein (IX-bp) isolated from the venom of the habu snake ( Trimeresurus flavoviridis ) is a disulfide-linked heterodimer consisting of homologous subunits A and B. The structure of IX-bp has been solved by X-ray crystallography at 2.6 A resolution to a crystallographic R -value of 0.181. The main-chain fold of each subunit is homologous to the carbohydrate-recognition domain of C-type lectins (C-type CRDs) except for the extended central loop. The structure is almost identical with that of Factors IX and X-binding protein (IX/X-bp) as expected from the high level of amino acid sequence homology. The functional difference in ligand recognition from IX/X-bp must reside in the amino acid differences. A continuity of different amino acid residues located from the C-terminal of the second α-helIX to the following loop forms the local conformational difference in this region between the two proteins. This loop participates in the formation of the concave surface between the two subunits, the putative binding site for the Gla-domain (γ-carboxyglutamic acid-containing domain) of the Coagulation Factors. Another difference between the two proteins is in the relative disposition of subunits A and B. When the B subunits are superimposed, about a 6 ° rotation is required for the superposition of the A subunits. A calcium ion links the second α-helIX region to the C-terminal tail in each subunit and helps to stabilize the structure for Gla-domain binding. The interface created by the central loop swapping in the dimer IX-bp is almost identical with that seen within the monomeric C-type CRDs. This dimer forms as the result of the amino acid deletion in the linker region of the central loop of the original C-type lectins. Such a dimerization disrupts the lectin active site and creates a Gla-domain binding site, imparting functional diversity.
-
blood Coagulation Factor IX binding protein from the venom of trimeresurus flavoviridis purification and characterization
Journal of Biochemistry, 1995Co-Authors: Hideko Atoda, Midori Ishikawa, Eiji Yoshihara, Fujio Sekiya, Takashi MoritaAbstract:: The Coagulation Factor IX/Factor X-binding protein (IX/X-bp) from the venom of Trimeresurus flavoviridis is a heterogeneous two-chain protein, and the structure of each chain is similar to that of the carbohydrate-recognition domain of C-type lectins, such as asialoglycoprotein receptors, pancreatic stone protein, and the Fc epsilon receptor for immunoglobulin E. Analysis of the binding properties of IX/X-bp revealed that it binds to the gamma-carboxyglutamic acid (Gla)-containing domains of Factors IX and X [Atoda, H. et al. (1994) Eur. J. Biochem. 224, 703-708]. In the present study, we isolated another anticoagulant protein that binds to Factor IX but is not to Factor X. This protein, designated IX-bp, inhibited Factor IXa-induced clotting but not Factor Xa-induced clotting, whereas IX/X-bp inhibits both. The concentration of IX-bp for half-maximal binding to solid-phase bovine Factor IX was 0.4 nM whereas IX-bp did not bind to Factor X even at 40 nM. The binding of IX-bp to solid-phase Factor IX was inhibited by the addition of Gla-domain peptide of Factor IX, indicating that IX-bp binds to the Gla-domain region of Factor IX. IX-bp had two Ca(2+)-binding sites with different affinities for Ca2+ ions. At pH 7.5, the apparent Kd values for these sites were 14 and 130 microM, respectively. IX-bp was a two-chain protein (27.5-kDa band before reduction and 16.8- and 15.7-kDa bands after reduction on SDS-PAGE) and it reacted with immunoglobulin G against IX/X-bp. The complete amino acid sequence of IX-bp was determined. The 16.8-kDa chain (A chain) of IX-bp consisted of 129 residues, of which 19 were different from those in the A chain of IX/X-bp (129 residues). The sequence of the 15.7-kDa chain (B chain) was identical to that of the B chain of IX/X-bp (123 residues). We conclude that IX-bp is a protein that is structurally similar to but functionally different from IX/X-bp. The difference of binding specificity between IX-bp and IX/X-bp presumably arises from the sequence differences in the A chains.
-
regulation of the tertiary structure and function of Coagulation Factor IX by magnesium ii ions
Journal of Biological Chemistry, 1995Co-Authors: Fujio Sekiya, Hideko Atoda, Toshiko Yamashita, Yutaka Komiyama, Takashi MoritaAbstract:The indispensable role of Ca2+ ions in the maintenance of the functional tertiary structures of vitamin K-dependent Coagulation Factors has been definitively established but the participation of Mg2+ ions, another alkaline-earth metal that is present abundantly in blood plasma, in such a process is not yet understood. We show here that the Ca2+-stabilized conformation of Coagulation Factor IX undergoes a further conformational change upon binding of Mg2+ ions using three independent structural probes. The probes we used were (i) IX/X-bp, a snake venom anticoagulant that recognizes the Gla domains in Coagulation Factors IX and X, (ii) conformation-specific polyclonal antibodies against bovine Factor IX, and (iii) monoclonal antibodies against the Gla domain of human Factor IX. The binding of all these probes had an absolute requirement for Ca2+ ions, and Mg2+ ions alone were ineffective. However, when added together with Ca2+ ions, Mg2+ ions at physiological concentrations greatly augmented the binding of these probes to Factor IX; the required concentration of Ca2+ ions was much reduced, and the affinity of each probe for Factor IX was increased even in the presence of an excess of Ca2+ ions. These results suggest the presence of a Mg2+-specific binding site that does not interact with Ca2+ ions in Factor IX. Furthermore, Mg2+ ions potentiated the susceptibility of Factor IX to activation by Factor XIa, concomitant with their effect on the conformation. Similarly, the required Ca2+ concentration was reduced by Mg2+ ions, and the rate of conversion to Factor IXa was increased by Mg2+ ions in the presence of an excess of Ca2+ ions. At a saturating concentration of Ca2+ ions (5 mM), addition of 1 mM Mg2+ reduced the apparent Km value for Factor IX from 0.31 to 0.18 μM, and in the presence of a physiological concentration of Ca2+ ions (1 mM), the reduction in Km by Mg2+ ions was far more striking (from 0.91 to 0.24 μM). The apparent Vmax values were hardly affected by Mg2+ ions. Our present data reveal a hitherto novel physiological role of the Mg2+ ions in plasma. Not only Ca2+ ions but also Mg2+ ions are important regulators of the stabilization of the native conformation of Factor IX as well as of its efficient activation.
E Santagostino - One of the best experts on this subject based on the ideXlab platform.
-
population pharmacokinetics of a new long acting recombinant Coagulation Factor IX albumin fusion protein for patients with severe hemophilia b
Journal of Thrombosis and Haemostasis, 2016Co-Authors: Ying Zhang, Christine Voigt, Iris Jacobs, Massimo Morfini, John Roberts, Debra M Bensenkennedy, E Santagostino, Annette Feussner, Jagdev SidhuAbstract:Essentials The new recombinant Factor IX (FIX) albumin fusion protein (rIX-FP) has a prolonged half-life. A population pharmacokinetic (PK) model was based on FIX activity levels of hemophilia B patients. The model was used to simulate different dosing scenarios of rIX-FP to help guide dosing. The population PK model supported prolonged dosing of rIX-FP with intervals of up to 2 weeks. Click to hear Prof.Makris's presentation on new treatments in hemophilia SUMMARY: Background The recombinant fusion protein linking recombinant Coagulation Factor IX with recombinant albumin (rIX-FP; Idelvion® ) exhibits a longer half-life than plasma-derived Factor IX (FIX) and the commercially available recombinant FIX products. Objectives (i) Characterize the population pharmacokinetics (PK) of rIX-FP in hemophilia B patients, (ii) identify covariates that are potential determinants of rIX-FP PK variability and (iii) simulate different dosing scenarios of rIX-FP following single and steady-state dosing. Patients/Methods A population PK model was developed based on FIX activity levels of 104 patients who had received treatment with rIX-FP. Patients were aged 1-65 years with FIX activity ≤ 2 IU dL-1 . PK sampling was performed for up to 14 days (336 h). Results Simulation of a single intravenous infusion of rIX-FP (25-75 IU kg-1 ) predicted that the median trough exogenous FIX activity levels would remain > 5 IU dL-1 for up to 16 days in adolescents/adults aged ≥ 12 years, up to 12 days in children aged 6 to 5 IU dL-1 for the duration of the dosing interval for the 25, 35 and 40 IU kg-1 weekly regimens and for 75 IU kg-1 every 14 days in adolescents/adults, and for the 35 and 40 IU kg-1 weekly regimens in children. Conclusion The population PK model developed here correlates well with observed clinical data and supports prolonged dosing of rIX-FP with intervals of up to 2 weeks.
-
results of a phase i ii open label safety and efficacy trial of Coagulation Factor IX recombinant albumin fusion protein in haemophilia b patients
Haemophilia, 2015Co-Authors: Uri Martinowitz, Christine Voigt, Iris Jacobs, Toshko Lissitchkov, Aaron Lubetsky, G Jotov, Tami Barazanibrutman, T Wuerfel, E SantagostinoAbstract:Introduction rIX-FP is a Coagulation Factor IX (recombinant), albumin fusion protein with more than fivefold half-life prolongation over other standard Factor IX (FIX) products available on the market. Aim This prospective phase II, open-label study evaluated the safety and efficacy of rIX-FP for the prevention of bleeding episodes during weekly prophylaxis and assessed the haemostatic efficacy for on-demand treatment of bleeding episodes in previously treated patients with haemophilia B. Methods The study consisted of a 10–14 day evaluation of rIX-FP pharmacokinetics (PK), and an 11 month safety and efficacy evaluation period with subjects receiving weekly prophylaxis treatment. Safety was evaluated by the occurrence of related adverse events, and immunogenic events, including development of inhibitors. Efficacy was evaluated by annualized spontaneous bleeding rate (AsBR), and the number of injections to achieve haemostasis. Results Seventeen subjects participated in the study, 13 received weekly prophylaxis and 4 received episodic treatment only. No inhibitors were detected in any subject. The mean and median AsBR were 1.25, and 1.13 respectively in the weekly prophylaxis arm. All bleeding episodes were treated with 1 or 2 injections of rIX-FP. Three prophylaxis subjects who were treated on demand prior to study entry had >85% reduction in AsBR compared to the bleeding rate prior to study entry. Conclusion This study demonstrated the efficacy for weekly routine prophylaxis of rIX-FP to prevent spontaneous bleeding episodes and for the treatment of bleeding episodes. In addition no safety issues were detected during the study and an improved PK profile was demonstrated.
Uri Martinowitz - One of the best experts on this subject based on the ideXlab platform.
-
long acting recombinant Coagulation Factor IX albumin fusion protein rIX fp in hemophilia b results of a phase 3 trial
Blood, 2016Co-Authors: Elena Santagostino, Johannes Oldenburg, Claude Negrier, Uri Martinowitz, Toshko Lissitchkov, Brigitte Panpetesch, Hideji Hanabusa, Lisa N Boggio, Ingrid Pabinger, Mario Von Depka ProndzinskiAbstract:A global phase 3 study evaluated the pharmacokinetics, efficacy, and safety of recombinant fusion protein linking Coagulation Factor IX with albumin (rIX-FP) in 63 previously treated male patients (12-61 years) with severe hemophilia B (Factor IX [FIX] activity ≤2%). The study included 2 groups: group 1 patients received routine prophylaxis once every 7 days for 26 weeks, followed by either 7-, 10-, or 14-day prophylaxis regimen for a mean of 50, 38, or 51 weeks, respectively; group 2 patients received on-demand treatment of bleeding episodes for 26 weeks and then switched to a 7-day prophylaxis regimen for a mean of 45 weeks. The mean terminal half-life of rIX-FP was 102 hours, 4.3-fold longer than previous FIX treatment. Patients maintained a mean trough of 20 and 12 IU/dL FIX activity on prophylaxis with rIX-FP 40 IU/kg weekly and 75 IU/kg every 2 weeks, respectively. There was 100% reduction in median annualized spontaneous bleeding rate (AsBR) and 100% resolution of target joints when subjects switched from on-demand to prophylaxis treatment with rIX-FP (P< .0001). The median AsBR was 0.00 for all prophylaxis regimens. Overall, 98.6% of bleeding episodes were treated successfully, including 93.6% that were treated with a single injection. No patient developed an inhibitor, and no safety concerns were identified. These results indicate rIX-FP is safe and effective for preventing and treating bleeding episodes in patients with hemophilia B at dosing regimens of 40 IU/kg weekly and 75 IU/kg every 2 weeks. This trial was registered at www.clinicaltrials.gov as #NCT0101496274.
-
results of a phase i ii open label safety and efficacy trial of Coagulation Factor IX recombinant albumin fusion protein in haemophilia b patients
Haemophilia, 2015Co-Authors: Uri Martinowitz, Christine Voigt, Iris Jacobs, Toshko Lissitchkov, Aaron Lubetsky, G Jotov, Tami Barazanibrutman, T Wuerfel, E SantagostinoAbstract:Introduction rIX-FP is a Coagulation Factor IX (recombinant), albumin fusion protein with more than fivefold half-life prolongation over other standard Factor IX (FIX) products available on the market. Aim This prospective phase II, open-label study evaluated the safety and efficacy of rIX-FP for the prevention of bleeding episodes during weekly prophylaxis and assessed the haemostatic efficacy for on-demand treatment of bleeding episodes in previously treated patients with haemophilia B. Methods The study consisted of a 10–14 day evaluation of rIX-FP pharmacokinetics (PK), and an 11 month safety and efficacy evaluation period with subjects receiving weekly prophylaxis treatment. Safety was evaluated by the occurrence of related adverse events, and immunogenic events, including development of inhibitors. Efficacy was evaluated by annualized spontaneous bleeding rate (AsBR), and the number of injections to achieve haemostasis. Results Seventeen subjects participated in the study, 13 received weekly prophylaxis and 4 received episodic treatment only. No inhibitors were detected in any subject. The mean and median AsBR were 1.25, and 1.13 respectively in the weekly prophylaxis arm. All bleeding episodes were treated with 1 or 2 injections of rIX-FP. Three prophylaxis subjects who were treated on demand prior to study entry had >85% reduction in AsBR compared to the bleeding rate prior to study entry. Conclusion This study demonstrated the efficacy for weekly routine prophylaxis of rIX-FP to prevent spontaneous bleeding episodes and for the treatment of bleeding episodes. In addition no safety issues were detected during the study and an improved PK profile was demonstrated.
-
phase i ii open label multicenter safety efficacy and pk study of a recombinant Coagulation Factor IX albumin fusion protein rIX fp in subjects with hemophilia b
Thrombosis Research, 2013Co-Authors: Uri Martinowitz, Aaron LubetskyAbstract:Recombinant fusion protein linking Coagulation Factor IX with albumin (rIX-FP) is a novel recombinant albumin fusion protein designed to extend the half-life of recombinant Factor IX (rFIX), which is used in the management of hemophilia B. Clinical evaluation of rIX-FP in humans is underway, including a recently completed phase I/II, open-label, multicenter, study that assessed the safety, pharmacokinetics, and efficacy of rIX-FP in patients with severe hemophilia B. A total of 17 patients received rIX-FP (25 IU/kg) as either on-demand therapy (n = 4) for 20 weeks or weekly prophylaxis (n = 13) for up to 44 weeks. Preliminary results confirm that rIX-FP has an excellent safety profile and a pharmacokinetic profile highlighted by a marked extended half-life, suggesting that weekly prophylaxis with rIX-FP at a dose of 25 IU/kg may be appropriate in patients with severe hemophilia B, and that extended dosing intervals (10-14 days) may be feasible in some patients. A phase II/III study evaluating the safety and efficacy of rIX-FP in patients with hemophilia B is underway.