Pharmacokinetics of subcutaneously administered etanercept in subjects with psoriasis.
OBJECTIVE
To present the results of the pharmacokinetic analysis of the concentration-time profiles of etanercept, a soluble receptor tumour necrosis factor (TNF) antagonist, in more than 1300 subjects with psoriasis.


METHODS
Pharmacokinetic samples were collected in one phase-2 and two phase-3 placebo-controlled, randomized clinical trials. Study 1 evaluated a 25-mg twice weekly (BIW) etanercept dosing regimen administered by subcutaneous (s.c.) injection for 24 weeks. Study 2 evaluated 25-mg BIW and 50-mg BIW s.c. doses for 12 weeks. Study 3 evaluated 25 mg once weekly (QW), 25 mg BIW and 50 mg BIW s.c. doses for 24 weeks.


RESULTS
The mean +/- SD steady-state predose serum concentrations of etanercept for the 25-mg BIW arm at 12 weeks in study 1 were 1590 +/- 885 ng ml(-1). In study 2, mean +/- SD etanercept steady-state concentrations at 12 weeks were 1900 +/- 1110 ng ml(-1) in the 25-mg BIW group and 3830 +/- 1870 ng ml(-1) in the 50-mg BIW group. The mean +/- SD steady-state predose serum concentrations of etanercept at 12 weeks in study 3 were 768 +/- 475 ng ml(-1) for the 25-mg QW regimen, 1990 +/- 1030 ng ml(-1) for the 25-mg BIW regimen and 4020 +/- 2100 ng ml(-1) for the 50-mg BIW regimen.


CONCLUSIONS
Pharmacokinetic results were highly consistent across clinical trials. The concentration-time profiles displayed dose proportionality. Etanercept concentrations in subjects with psoriasis are similar to the concentrations in subjects with rheumatoid arthritis.
Nestorov
Ivan
I
ZymoGenetics, Seattle, WA, USA.
Zitnik
Ralph
R
DeVries
Todd
T
Nakanishi
Arline M
AM
Wang
Andrea
A
Banfield
Christopher
C
D000279:Administration, Cutaneous; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004311:Double-Blind Method; D000068800:Etanercept; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000188:drug therapy*; D018124:Receptors, Tumor Necrosis Factor / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents; D018124:Receptors, Tumor Necrosis Factor; D000068800:Etanercept