Investigating clearance mechanisms for recombinant activated factor VII in a perfused liver model.
Clearance mechanisms for recombinant activated human FVII (rFVIIa; NovoSeven), a heterogeneously glycosylated protein, have yet to be fully elucidated, but may involve the liver. The effects of the gamma-carboxy glutamic acid (Gla) domain and the sialic acid content of the protein on rFVIIa clearance were investigated following intravenous administration of rFVIIa lacking the Gla domain, des(1-44) rFVIIa and asialo-rFVIIa in pharmacokinetic (PK) studies and perfused rat livers. PK parameters for both rFVIIa and des(1-44) rFVIIa had similar biphasic clearance profiles, as well as half-lives ([t(1/2)]=80 and 88 minutes, respectively), while asialo-rFVIIa was cleared quickly (t(1/2)=21 minutes) with a linear clearance profile. Perfused liver studies with all proteins (10 nM) mirrored the trends in profiles observed in the PK study. rFVIIa and des(1-44) rFVIIa were cleared to a similar extent, 41% and 35%, respectively, after 1 h, whereas plasma-derived FVII from humans (which has a higher sialylation content than rFVIIa) was cleared to a lesser extent (21%). Asialo-rFVIIa, on the other hand, was almost totally cleared and when an excess of asialo-orosomucoid was added to the perfusate, its clearance was significantly reduced (by 34%) and also for rFVIIa, albeit to a lesser extent (by 14%). Together these data suggest that carbohydrate receptor(s) (e.g. the asialoglycoprotein receptor, ASGPR) play a role in asialo-rFVIIa and rFVIIa clearance. In vivo and liver clearance data correlated well showing similar trends and indicated that rFVIIa clearance is not affected by the Gla domain, but rather by a subpopulation of N-glycosylated structures on rFVIIa.
Exploratory ADME, Biopharmaceutical Research Unit, Novo Nordisk A/S, Måløv, Denmark. rupa@novonordisk.com
Rupa  S
R
Appa
Charlotte
C
Theill
Lene
L
Hansen
Judi
J
Møss
Carsten
C
Behrens
Else Marie
EM
Nicolaisen
Niels K
NK
Klausen
Michael S
MS
Christensen
D000818:Animals; D037263:Asialoglycoprotein Receptor / Q000378:metabolism; D001212:Asialoglycoproteins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D003029:Coagulants / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D015942:Factor VIIa / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006031:Glycosylation; D006207:Half-Life; D006801:Humans; D007275:Injections, Intravenous; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D009961:Orosomucoid / Q000031:analogs & derivatives / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics
D037263:Asialoglycoprotein Receptor; D001212:Asialoglycoproteins; D003029:Coagulants; D009961:Orosomucoid; D010446:Peptide Fragments; D011994:Recombinant Proteins; C017030:asialoorosomucoid; C087993:des(1-44) factor VIIa; C103587:recombinant FVIIa; D015942:Factor VIIa