Population Pharmacokinetic Modeling and Simulation of Recombinant Single-Chain Factor VIII (r VIII-SingleChain) in Patients with Hemophilia a

Abstract Introduction: Hemophilia A is a rare but serious X-linked recessive bleeding disorder that affects males and is characterized by a deficiency in the plasma protein known as coagulation Factor VIII. rVIII-SingleChain is a proprietary, lyophilized formulation of clotting factor VIII (FVIII) produced by recombinant technology. As part of the clinical development of rVIII-SingleChain, a population pharmacokinetic (PK) analysis was undertaken, utilizing data from Study CSL627_1001 in subjects with hemophilia A, with the objectives of (a) characterizing the PK of rVIII-SingleChain at a population level, (b) assessing the ability of various patient characteristics (e.g., von Willebrand factor, VWF) to describe variability in the PK parameters, and (c) enable population-based simulations of rVIII-SingleChain dosing regimens that may provide improved prophylaxis coverage compared with octocog alfa (Advate®). Methods: Twenty-seven male subjects (aged 19-60 years) enrolled in Study CSL627_1001 (Part 1) received a single 50 IU/kg IV infusion of Advate®, followed by a single 50 IU/kg IV infusion of rVIII-SingleChain, with a minimum 4-day washout period. Plasma PK samples (for the determination of FVIII activity) were collected over 72 hours for both Advate® and rVIII-SingleChain (at pre-specified time points) and were measured by a validated chromogenic assay. Population PK models were developed separately for rVIII-SingleChain and Advate®, using the NONMEM 7 with FOCEI method. Various covariates, including VWF, body weight, and effect of age on clearance (CL) and volume of distribution were tested. Bootstrap and visual predictive check (VPC) were used for model evaluation. Simulations of different dosing regimens were performed to evaluate the FVIII activity plasma exposure profiles that may provide improved prophylaxis coverage. Results: A two-compartmental model with first-order elimination was developed to describe FVIII plasma activity data for both rVIII-SingleChain and Advate®. VWF was found to be a significant covariate influence on FVIII plasma activity CL, whilst body weight influenced both CL and volume of distribution in the central compartment. Population parameter estimates indicated a lower CL (2.02 vs 2.49 dL/h) and longer half-life (13.1 vs 9.3 h) for rVIII-SingleChain compared with Advate®. The results of bootstrap and VPC implied that the model was stable, and the parameters were estimated with good precision. PK simulations indicated that rVIII-SingleChain, at the same doses and frequencies, resulted in higher FVIII plasma activities throughout the dosing period, as reflected in higher area-under-the-curve (AUC). The dosing regimens for the simulations were designed based on the dosing recommendations of the Advate® label and rVIII-SingleChain phase III study. The results showed that rVIII-SingleChain provided a higher percentage of subjects with trough levels of at least 1% FVIII plasma activity, compared with Advate® at the same dosing regimen. Every 3 days dosing at 40-50 IU/kg rVIII-SingleChain was predicted to achieve similar prophylaxis protection compared with Advate® every 2 days (i.e., about 90% of subjects with trough levels of at least 1% FVIII plasma activity). In addition, 73-90% of subjects were predicted to achieve trough levels of at least 1% FVIII plasma activity with twice weekly dosing (4- and 3-day schedule) at 50 IU/kg rVIII-SingleChain, compared with 65-80% of subjects dosed with Advate® using the same regimen. Conclusion: The population model shows that rVIII-SingleChain has a longer half-life, lower CL and higher AUC compared with Advate®. Simulations demonstrated that rVIII-SingleChain resulted in higher trough concentrations when compared with Advate®, indicating the possibility of greater prophylaxis coverage. Disclosures Zhang: CSL Behring: Employment. Limsakun:CSL Behring: Employment. Bensen-Kennedy:CSL Behring: Employment. Veldman:CSL Behring GmbH: Employment. Yao:CSL Behring: Employment.

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A Method for Deriving Pharmacokinetic Constants for Factor VIII and IX from Limited Blood Sampling

Blood ◽

10.1182/blood.v126.23.3501.3501 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3501-3501 ◽

Cited By ~ 1

Author(s):

Miguel Antonio Escobar ◽

Daniel Preston Bond ◽

Madeline Cantini ◽

Krishna Cannon

Keyword(s):

Factor Viii ◽

Half Life ◽

Research Funding ◽

Decay Constant ◽

Hemophilia A ◽

Health Science ◽

Blood Sampling ◽

Population Pharmacokinetic ◽

Viii And Ix ◽

Trough Levels

Abstract Introduction The treatment of hemophilia A and B is based on the replacement of the deficient factor dosed by weight. However, dosing for hemophilia treatment has been arrived at by empiric assessment, essentially "trial and error" based on the pharmacokinetics (PK) of the factors and the characteristics of the replacement product. In the last decade clinical pharmacokinetics has gained popularity in hemophilia so that factor dosage can be adjusted according to the requirement of the individual patient. Factor-specific population pharmacokinetic models have been developed for individualized treatment of patients with hemophilia A and B. The math modeling technique presented in this project relies on minimal blood sampling to derive the constants necessary to predict the peak and trough levels within the commonly excepted error bounds. Methods Data that included FVIII, FIX levels and weight were obtained retrospectively from severe hemophilia A and B adult patients and approved by the ethics committee of the University of Texas Health Science Center. A single compartment decay model equation was used in both a custom iOS application and an Excel spreadsheet to calculate the decay constant between any 2 points on a decay curve. Using this local constant as the half-life in the standard decay equation allowed the calculation of the peak at time = 0. This peak combined with dosing information and the subject's weight allowed the calculation of the Recovery. These 2 constants in the equation: Level=(dose*Recovery/weight)*0.5^(time/half-life) allowed the calculation of the level at any point on the curve. Using this method on several example datasets showed that the model is reasonably able to predict peak and trough levels for both factor VIII and IX. Because of the time dependent nature of the local decay constant, better results are obtained using data points after the first half of the expected half-life. This method can also be used to predict steady state levels, peaks and troughs for any prophylaxis schedule. Conclusion Appropriate dosing of factor VIII or IX is at best an approximate calculation. The method described in this publication generates a math model that is generally as accurate as a multiple sample PK study with far fewer blood samples taken. Clinical applications of this model can be utilized to predict factor levels after a single infusion of factor VIII/IX in adults that are treated on-demand or prophylaxis. It can also be utilized in individuals that are infusing extended half-life products or in the surgical setting. Disclosures Escobar: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bond:Pfizer: Consultancy, Research Funding. Cantini:Pfizer: Research Funding. Cannon:Pfizer: Research Funding.

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Site-Specific PEGylation of Factor VIII (PEG-FVIII) Preserves Full Clotting Activity and Extends Therapeutic Efficacy in HemophiliaA Dogs

Blood ◽

10.1182/blood.v112.11.511.511 ◽

2008 ◽

Vol 112 (11) ◽

pp. 511-511 ◽

Cited By ~ 3

Author(s):

Tongyao Liu ◽

David Lillicrap ◽

Xin Zhang ◽

Andrea Labelle ◽

Sandra Powell ◽

...

Keyword(s):

Factor Viii ◽

Whole Blood ◽

Half Life ◽

Therapeutic Efficacy ◽

Neutralizing Antibodies ◽

Hemophilia A ◽

Volume Of Distribution ◽

Pharmacokinetic Analysis ◽

Site Specific ◽

Intravenous Injections

Abstract To improve the effectiveness of Factor VIII replacement therapy for Hemophilia A, we sought to develop a PEGylated Factor VIII that would effectively treat bleeding episodes, while reducing the frequency of intravenous injections required for prophylaxis. Previously, we found that the site-specific PEGylation of Factor VIII (PEG-FVIII) preserves full clotting activity, prolongs circulating half-life and extends therapeutic efficacy in a number of bleeding models in hemophilic mice. To further characterize its activity, four naïve Hemophilia A dogs were treated with either PEG-FVIII or unmodified BDD-FVIII in a cross-over study design. All treated dogs showed normalized Whole Blood Clotting Time (WBCT), whole blood Thromboelastograph (TEG) profile, and Cuticle Bleeding Time within 30 min from dosing. Pharmacokinetic analysis of the decay of plasma FVIII activity and antigen levels showed that PEG-FVIII achieved 2-fold longer half-life and reduced clearance and volume of distribution relative to BDD-FVIII. Consistently, PEG-FVIII also demonstrated significantly prolonged efficacy relative to BDD-FVIII by measurement of WBCT and TEG. Both BDD-FVIII and PEG-FVIII were well tolerated in naïve HemA dogs, normal hematology and serum chemistry values were observed following administration. However, two naive dogs that received BDD-FVIII and one naive dog that received PEG-FVIII developed detectable neutralizing antibodies to human FVIII as early as on day 9 post-treatment. In summary, consistent with our previously reported findings in hemophilic mice, in comparison to BDD-FVIII, PEG-FVIII demonstrated superior half-life, full activity in stopping acute bleeding and prolonged efficacy in hemophilia A dogs. Taken together, the results support the use of site-specific PEGylation to create a homogeneous therapeutic for both prophylactic and on-demand treatment of patients with Hemophilia A.

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Pharmacokinetic Properties of Recombinant Factor VIII Compared with a Monoclonally Purified Concentrate (Hemofil® M)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646292 ◽

1992 ◽

Vol 68 (04) ◽

pp. 433-435 ◽

Cited By ~ 30

Author(s):

M Morfini ◽

G Longo ◽

A Messori ◽

M Lee ◽

G White ◽

...

Keyword(s):

Factor Viii ◽

Half Life ◽

Hemophilia A ◽

Recombinant Dna ◽

Volume Of Distribution ◽

Pharmacokinetic Properties ◽

Recombinant Fviii ◽

Reported Data ◽

In Vivo Recovery

SummaryA recombinant FVIII preparation, Recombinate™, was compared with a high-purity plasma-derived concentrate, Hemofil® M, in 47 hemophilia A patients in a cross-over evaluation of pharmacokinetic properties. The recombinant material showed a significantly lower clearance, volume of distribution, and higher in vivo recovery, but a similar half-life to the plasma-based product.In a comparison with reported data from other standard concentrates, the recombinant preparation exhibited potentially better pharmacokinetic properties in that its clearance was slower and its half-life was longer.We conclude that the recombinant DNA method of preparation does not adversely affect the biological and pharmacological characteristics of the factor VIII molecule.

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Cross-evaluation of Pharmacokinetic-Guided Dosing Tools for Factor VIII

Thrombosis and Haemostasis ◽

10.1055/s-0038-1623531 ◽

2018 ◽

Vol 118 (03) ◽

pp. 514-525 ◽

Cited By ~ 8

Author(s):

T. Preijers ◽

I. van Moort ◽

K. Fijnvandraat ◽

F. Leebeek ◽

M. Cnossen ◽

...

Keyword(s):

Factor Viii ◽

Half Life ◽

Trough Level ◽

Patient Characteristics ◽

Population Pharmacokinetic ◽

Parameter Estimates ◽

Haemophilia A ◽

Blood Samples ◽

Fviii Activity ◽

Recombinant Fviii

Background Patients with severe and moderate haemophilia A are treated prophylactically with factor VIII (FVIII) concentrate. Individualization of prophylaxis can be achieved by pharmacokinetic (PK)-guided dosing. Aim In this study, the performance of three PK tools (myPKFiT, Web-Accessible Population Pharmacokinetic Service-Hemophilia [WAPPS] and NONMEM) is compared. Methods In 39 patients, with severe or moderate haemophilia A, blood samples were collected 4, 24 and 48 hours after administration of 50 IU kg−1 of recombinant FVIII (Advate [n = 30] or Kogenate [n = 9]). FVIII dose, FVIII activity and patient characteristics were entered into the three PK tools. Obtained PK parameters and dosing advises were compared. Results myPKFiT provided PK parameters for 24 of 30 patients receiving Advate, whereas WAPPS and NONMEM provided estimates for all patients. Half-life was different among the three methods: medians were 12.6 hours (n = 24), 11.2 hours (n = 30) and 13.0 hours (n = 30) for myPKFiT, WAPPS and NONMEM (p < 0.001), respectively. To maintain a FVIII trough level of 0.01 IU mL−1 after 48 hours, doses for myPKFiT and NONMEM were 15.1 and 11.0 IU kg−1 (p < 0.01, n = 11) and for WAPPS and NONMEM were 9.0 and 8.0 IU kg−1 (p < 0.01, n = 23), respectively. In nine patients receiving Kogenate, WAPPS and NONMEM produced different PK-parameter estimates; half-life was 15.0 and 12.3 hours and time to 0.05 IU mL−1 was 69.2 and 60.8 hours, respectively (p < 0.01, n = 9). However, recommended doses to obtain these levels were not different. Conclusion The three evaluated PK tools produced different PK parameters and doses for recombinant FVIII. Haematologists should be aware that recommended doses may be influenced by the choice of PK tool.

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Use of a Population Pharmacokinetic Model of ADVATE In Pediatric and Adult Patients with Hemophilia A Permits Limited Blood Sampling for Individual Dose Tailoring.

Blood ◽

10.1182/blood.v116.21.1416.1416 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1416-1416

Author(s):

MyungShin Oh ◽

Sven Björkman ◽

Phillip Schroth ◽

Sandor Fritsch ◽

Peter W Collins ◽

...

Keyword(s):

Body Weight ◽

Hemophilia A ◽

Volume Of Distribution ◽

Sampling Time ◽

Adult Patients ◽

Population Pharmacokinetic ◽

Data Sets ◽

Time Points ◽

Population Pk ◽

Post Infusion

Abstract Abstract 1416 Introduction: A population pharmacokinetic (PK) model of a recombinant FVIII (rFVIII) was established on ADVATE® (Antihemophilic Factor (Recombinant), Plasma/Albumin-Free Method) studies in pediatric and adult patients with hemophilia A. The objective of this analysis was to evaluate the effect of reduced PK sampling time points on the estimated PK parameters in the population PK model. Patients and Methods: Plasma FVIII activity PK data were collected for 3 ADVATE® clinical trials in previously treated patients: 184 full PK data sets (11 time points) for 100 adults/adolescents, aged 10 to 65 years, and from 52 reduced sample PK data sets (5 time points) for 52 children, aged 1 to 6 years. A population PK analysis was conducted on a two-compartment structure model and the covariate effect of age and weight was explored. Four reduced sampling scenarios from the full 10 post-infusion sampling time points, were investigated: 1) Reduced to 4 (1 hr, 9 hr, 24 hr, and 48 hr), 2) Reduced to 3 (6 hr, 24 hr, and 48 hr), 3) Reduced to 2 (6 hr and 24 hr), and 4) Reduced to 1 sampling time points (24 hr post-infusion). After applying the reduced sampling on a random 10% of sampling set at a time in the population PK model, the differences in model estimates and individual PK estimates between full and reduced sampling, were evaluated. Results: The two-compartment population PK model adequately described the data. Clearance (CL) was significantly correlated with age and body weight and central volume of distribution was also related with body weight. Absolute deviations (%) from the estimates using full PK sampling in the Individual PK estimates (CL, Vss, and Half-life) using each of the reduced sampling time points were showed in the below table. Conclusions: It appears that PK parameters estimated using population PK model are robust to reduced sampling time points. Accurate measurement of PK on reduced samples gives patients and clinicians the opportunity to design treatment regimens that are better tailored to individuals. Disclosures: Oh: Baxter: Employment. Björkman:Baxter: Consultancy; Octapharma: Consultancy. Schroth:Baxter: Employment. Fritsch:Baxter: Employment. Collins:NovoNordisk: Consultancy, Honoraria, The EACH2 registry was funded by Novonordisk; Baxter Healthcare: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Fischer:Baxter: Consultancy; NovoNordisk: Consultancy. Blanchette:Bayer: Consultancy; Baxter: Research Support. Casey:Baxter: Employment. Spotts:Baxter: Employment. Ewenstein:Baxter Bioscience: Employment.

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Recombinant, B-domain Deleted Factor VIII (r-VIII SQ): Pharmacokinetics and Initial Safety Aspects in Hemophilia A Patients

Thrombosis and Haemostasis ◽

10.1055/s-0038-1655957 ◽

1997 ◽

Vol 77 (02) ◽

pp. 298-302 ◽

Cited By ~ 71

Author(s):

K Fijnvandraat ◽

E Berntorp ◽

J W ten Cate ◽

H Johnsson ◽

M Peters ◽

...

Keyword(s):

Factor Viii ◽

Half Life ◽

Hemophilia A ◽

Peak Plasma ◽

Dose Range ◽

Pharmacokinetic Profile ◽

Volume Of Distribution ◽

Repeated Doses ◽

Recombinant Fviii

SummaryThe pharmacokinetics of a second-generation recombinant B-domain deleted factor VIII (FVIII) preparation (r-VIII SQ) were studied in 36 patients with severe hemophilia A. In contrast to full-length recombinant FVIII, no albumin needs to be added to stabilize the final formulation of this B-domain deleted FVIII preparation.The in vivo recovery and half-life of r-VIII SQ were similar to those of plasma-derived (pd) FVIII (mean half-life of r-VIII SQ, 11.7 h). The volume of distribution and clearance were slightly, but significantly, higher for r-VIII SQ than for pdFVIII (p<0.05). Peak plasma levels of FVIII were consistently related to the administered dose of r-VIII SQ (r = 0.94, p<0.0001). The pharmacokinetic profile of r-VIII SQ remained essentially unchanged in a dose range of 25-100 IU/kg body weight and could be reproduced after repeated doses. r-VIII SQ was well tolerated.In conclusion, deletion of the B-domain of FVIII does not influence its in vivo pharmacokinetics.

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The Effect of Adrenaline Infusions on Blood Coagulation in Normal and Haemophilia B Dogs

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649437 ◽

1966 ◽

Vol 15 (03/04) ◽

pp. 349-364 ◽

Cited By ~ 5

Author(s):

A.H Özge ◽

H.C Rowsell ◽

H.G Downie ◽

J.F Mustard

Keyword(s):

Body Weight ◽

Factor Viii ◽

Factor Ix ◽

Clotting Factor ◽

Blood Ph ◽

Order Of Magnitude ◽

Dose Dependent ◽

Generation Test ◽

Plasma Activity

SummaryThe addition of trace amounts of adrenaline to whole blood in plasma in vitro increased factor VIII, factor IX and whole plasma activity in the thromboplastin generation test. This was dose dependent.Adrenaline infusions less than 22 (μg/kg body weight in normal dogs accelerated clotting, increased factor IX, factor VIII and whole plasma activity in the thromboplastin generation test and caused a fall in blood pH. In a factor IX deficient dog, there was no increase in factor IX activity. After adrenaline infusions, however, the other changes occurred and were of the same order of magnitude as in the normal. Adrenaline in doses greater than 22 μg/kg body weight did not produce as great an effect on clotting in normal or factor IX deficient dogs. The platelet count in the peripheral blood was increased following the infusion of all doses of adrenaline. These observations suggest that the accelerating effect of adrenaline on clotting is not mediated through increase in activity of a specific clotting factor.

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MODERN POSSIBILITIES OF SUBSTITUTION THERAPY AND HEMOPHILIA A PREVENTION IN CHILDREN

PEDIATRIA Journal named after G N SPERANSKY ◽

10.24110/0031-403x-2021-100-2-182-187 ◽

2021 ◽

Vol 100 (2) ◽

pp. 182-187

Author(s):

P.A. Zharkov ◽

Keyword(s):

Factor Viii ◽

Half Life ◽

Hemophilia A ◽

Safety Data ◽

Residual Activity ◽

Recombinant Factor Viii ◽

Substitution Therapy ◽

Life Effectiveness ◽

Intravenous Injections ◽

Prophylactic Use

Currently, the prophylactic use of factor VIII concentrate is the «gold standard» for treatment of an uncomplicated severe hemophilia A without inhibitors. However, there are a number of difficulties associated with frequent intravenous injections to maintain the activity of factor VIII above 1% in children and adolescents, which cannot but affect the adherence of patients to this type of treatment. The article discusses modern approaches to extend the half-life of recombinant factor VIII allowing to reduce the frequency of infusions and increase the residual activity of the deficient factor. On the example of efmoroctocog alpha, the first recombinant factor VIII concentrate registered in our country with a prolonged half-life, effectiveness and safety data of this class of drugs approved for use in children is presented.

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