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In vivo recovery of factor VIII and factor IX: intra- and interindividual variance in a clinical setting.

Bjorkman, S; Folkesson, A and Berntorp, Erik LU (2007) In Haemophilia 13(1). p.2-8
Abstract
In vivo recovery IVR) is traditionally used as a parameter to characterize the pharmacokinetic properties of coagulation factors. It has also been suggested that dosing of factor VIII (FVIII) and factor IX (FIX) can be adjusted according to the need of the individual patient, based on an individually determined IVR value. This approach, however, requires that the individual IVR value is more reliably representative for the patient than the mean value in the population, i.e. that there is less variance within than between the individuals. The aim of this investigation was to compare intra- and interindividual variance in TVR (as U dL(-1) per U kg(-1)) for FVIII and plasma-derived FIX in a cohort of nonbleeding patients with haemophilia. The... (More)
In vivo recovery IVR) is traditionally used as a parameter to characterize the pharmacokinetic properties of coagulation factors. It has also been suggested that dosing of factor VIII (FVIII) and factor IX (FIX) can be adjusted according to the need of the individual patient, based on an individually determined IVR value. This approach, however, requires that the individual IVR value is more reliably representative for the patient than the mean value in the population, i.e. that there is less variance within than between the individuals. The aim of this investigation was to compare intra- and interindividual variance in TVR (as U dL(-1) per U kg(-1)) for FVIII and plasma-derived FIX in a cohort of nonbleeding patients with haemophilia. The data were collected retrospectively from six clinical studies, yielding 297 IVR determinations in 50 patients with haemophilia A and 93 determinations in 13 patients with haemophilia B. For FVIII, the mean variance within patients exceeded the between-patient variance. Thus, an individually determined IVR value is apparently no more informative than an average, or population, value for the dosing of FVIII. There was no apparent relationship between IVR and age of the patient (1.5-67 years). For FIX, the mean variance within patients was lower than the between-patient variance, and there was a significant positive relationship between IVR and age (13-69 years). From these data, it seems probable that using an individual IVR confers little advantage in comparison to using an age-specific population mean value. Dose tailoring of coagulation factor treatment has been applied successfully after determination of the entire single-dose curve of FVIII:C or FIX:C in the patient and calculation of the relevant pharmacokinetic parameters. However, the findings presented here do not support the assumption that dosing of FVIII or FIX can be individualized on the basis of a clinically determined IVR value. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
in vivo recovery, dosing, factor VIII, pharmacokinetics, variance, factor IX
in
Haemophilia
volume
13
issue
1
pages
2 - 8
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • wos:000243982900002
  • scopus:33845730827
ISSN
1351-8216
DOI
10.1111/j.1365-2516.2006.01401.x
language
English
LU publication?
yes
id
86addfd6-38f8-48e3-ba87-70723cb46c53 (old id 165066)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=17212717&dopt=Abstract
date added to LUP
2007-07-13 13:52:10
date last changed
2017-11-19 03:29:07
@article{86addfd6-38f8-48e3-ba87-70723cb46c53,
  abstract     = {In vivo recovery IVR) is traditionally used as a parameter to characterize the pharmacokinetic properties of coagulation factors. It has also been suggested that dosing of factor VIII (FVIII) and factor IX (FIX) can be adjusted according to the need of the individual patient, based on an individually determined IVR value. This approach, however, requires that the individual IVR value is more reliably representative for the patient than the mean value in the population, i.e. that there is less variance within than between the individuals. The aim of this investigation was to compare intra- and interindividual variance in TVR (as U dL(-1) per U kg(-1)) for FVIII and plasma-derived FIX in a cohort of nonbleeding patients with haemophilia. The data were collected retrospectively from six clinical studies, yielding 297 IVR determinations in 50 patients with haemophilia A and 93 determinations in 13 patients with haemophilia B. For FVIII, the mean variance within patients exceeded the between-patient variance. Thus, an individually determined IVR value is apparently no more informative than an average, or population, value for the dosing of FVIII. There was no apparent relationship between IVR and age of the patient (1.5-67 years). For FIX, the mean variance within patients was lower than the between-patient variance, and there was a significant positive relationship between IVR and age (13-69 years). From these data, it seems probable that using an individual IVR confers little advantage in comparison to using an age-specific population mean value. Dose tailoring of coagulation factor treatment has been applied successfully after determination of the entire single-dose curve of FVIII:C or FIX:C in the patient and calculation of the relevant pharmacokinetic parameters. However, the findings presented here do not support the assumption that dosing of FVIII or FIX can be individualized on the basis of a clinically determined IVR value.},
  author       = {Bjorkman, S and Folkesson, A and Berntorp, Erik},
  issn         = {1351-8216},
  keyword      = {in vivo recovery,dosing,factor VIII,pharmacokinetics,variance,factor IX},
  language     = {eng},
  number       = {1},
  pages        = {2--8},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Haemophilia},
  title        = {In vivo recovery of factor VIII and factor IX: intra- and interindividual variance in a clinical setting.},
  url          = {http://dx.doi.org/10.1111/j.1365-2516.2006.01401.x},
  volume       = {13},
  year         = {2007},
}