A pharmacodynamic model of erythropoietin therapy for uremic anemia.
Fifty-seven patients receiving chronic high-flux hemodialysis began receiving recombinant alpha-human erythropoietin (rHuEPO). The mean initial rHuEPO dose used in 54 evaluable patients was 9963 +/- 4364 U/week; the final dose was 8972 +/- 4058 U/week. Treatment over a mean period of 154 +/- 40 days (84 to 224 days) resulted in an average increase in hematocrit from 24.7% +/- 3.7% to 32.5% +/- 4.4%. We present a model for these data that describes changes in hematocrit during rHuEPO therapy and that allows simultaneous estimation of red blood cell lifespan and rHuEPO-induced increases in red blood cell production rate. Analysis of the hematocrit values of the patients with the model, by use of NONMEM, a computer program for analysis of population data, reveals a nonlinear dose-response relationship with large interindividual variability (coefficient of variation) of about 50%. The estimated mean red blood cell lifespan is 64 days, with interindividual variability of about 30% (coefficient of variation). The intraindividual random variability in hematocrit about its prediction is +/- 5% of the prediction. For clinical dose adjustment, we present a method that uses only simple calculations.
Uehlinger
D E
DE
Hemodialysis Research Unit, Davies Medical Center, San Francisco, CA.
Gotch
F A
FA
Sheiner
L B
LB
D000740:Anemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D004905:Erythrocyte Aging / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology; D004921:Erythropoietin / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005260:Female; D014644:Genetic Variation / Q000502:physiology; D006400:Hematocrit; D006801:Humans; D008297:Male; D011994:Recombinant Proteins / Q000493:pharmacokinetics / Q000627:therapeutic use; D012984:Software; D014511:Uremia / Q000097:blood / Q000150:complications / Q000188:drug therapy*
D011994:Recombinant Proteins; D004921:Erythropoietin