title: Pharmacokinetics of CTLA4Ig fusion protein in healthy volunteers and patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To evaluate single-dose and multiple-dose pharmacokinetics of cytotoxic T-lymphocyte-associated antigen 4 fusion protein (CTLA4Ig) in healthy volunteers and patients with rheumatoid arthritis (RA).
  
  
  METHODS
  The clinical trials included two phase I open studies: study 1 was an open-label dose-escalation study in 27 healthy volunteers and study 2 was a single-group, open-label study in patients with rheumatoid arthritis. In study 2, 9 patients were arranged to receive 10 mg/kg of CTLA4Ig at 0, 2, 4, 8, 12, and 16 weeks. The concentration-time data obtained by a validated ELISA method were subjected to non-compartmental pharmacokinetic analysis by DAS 2.1 software.
  
  
  RESULTS
  In study 1, serum CTLA4Ig concentrations climbed rapidly to the peak and declined slowly with a t(1/2) of 15.1+/-2.6 d, 14.2+/-2.3 d, and 11.8+/-1.2 d after a single infusion of 1, 10, and 20 mg/kg, respectively. C(max) and AUC(0-infinity) increased proportionally with the dose. In study 2, the steady-state condition for CTLA4Ig following multiple doses of 10 mg/kg appeared to be attained at the fourth dose (d 56), with peak and trough concentrations of 239.8+/-45.3 mg/L and 20.5+/-7.9 mg/L, respectively. After multiple infusions, serum concentrations dropped slowly and the terminal half-life was 12.6+/-4.7 d.
  
  
  CONCLUSIONS
  Intravenous infusion of CTLA4Ig was well tolerated in healthy volunteers and patients with rheumatoid arthritis. CTLA4Ig exhibited linear pharmacokinetics over the dose range of 1 to 20 mg/kg in healthy volunteers. The pharmacokinetics in RA patients appeared to be similar to that in healthy volunteers. No system accumulation appeared upon repeated infusions of 10 mg/kg every 4 weeks.
authors.affiliation: Shanghai Key Laboratory of Cell Engineering and Shanghai National Engineering Research Center for Antibody Medicine, Shanghai, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.forename: Bi-rong
authors.initials: BR
authors.lastname: Lin
authors.forename: Bei
authors.initials: B
authors.lastname: Lin
authors.forename: Sheng
authors.initials: S
authors.lastname: Hou
authors.forename: Wei-zhu
authors.initials: WZ
authors.lastname: Qian
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Tan
authors.forename: Jian
authors.initials: J
authors.lastname: Ma
authors.forename: Bo-hua
authors.initials: BH
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Ai-dong
authors.initials: AD
authors.lastname: Wen
authors.forename: Ya-jun
authors.initials: YJ
authors.lastname: Guo
mesh_terms: D000069594:Abatacept; D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D019540:Area Under Curve; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D018796:Immunoconjugates / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D018796:Immunoconjugates; D000069594:Abatacept