Effects of chronic renal failure on the pharmacokinetics of ruboxistaurin and its active metabolite 338522.
BACKGROUND
Ruboxistaurin, a specific inhibitor of the beta(1) and beta(2) isoforms of protein kinase C, is currently in clinical development for the treatment of several diabetic microvascular complications. The major metabolite, N-desmethyl ruboxistaurin (metabolite 338522), is equipotent in its inhibitory activity. The elimination of ruboxistaurin and its metabolites is primarily through bile and the faecal route, with urinary excretion constituting only a minor route.


OBJECTIVE
To assess the effects of chronic renal insufficiency on the pharmacokinetics of ruboxistaurin and metabolite 338522.


METHODS
Six healthy subjects (creatinine clearance >80 mL/min/1.73 m(2)) and six end-stage renal disease (ESRD) subjects requiring long-term haemodialysis were studied. All subjects received a single oral dose of ruboxistaurin 32 mg followed by serial blood sampling up to 72 hours. ESRD subjects underwent haemodialysis approximately 58 hours after dosing, with blood samples obtained immediately before and after dialysis.


RESULTS
No differences were observed in the pharmacokinetic parameters (area under the plasma concentration-time curve from time zero to infinity [AUC(infinity)], maximum plasma concentration [C(max)] and elimination half-life [t(1/2)]) of ruboxistaurin and metabolite 338522 between healthy and ESRD subjects Plasma concentrations of ruboxistaurin were below the lower limit of quantification by the time of haemodialysis. The predicted post-dialysis plasma concentrations of metabolite 338522 were not statistically different from the observed values (p=0.163). Ruboxistaurin was well tolerated in both groups of subjects.


CONCLUSIONS
These results indicate that the kidney is not an important route of metabolism or excretion for ruboxistaurin and metabolite 338522. Based on the pharmacokinetic and tolerability findings, no formal dosage adjustment of ruboxistaurin should be required for patients with any degree of renal impairment who are undergoing haemodialysis.
Wise
Stephen
S
Lilly-NUS Centre for Clinical Pharmacology, National University of Singapore, Singapore. sdw@lilly.com
Yuen
Eunice
E
Chan
Clark
C
Poo
Yeo Kwee
YK
Teng
Lorraine
L
Lau
Titus
T
Voelker
James
J
D000328:Adult; D000465:Algorithms; D019540:Area Under Curve; D001711:Biotransformation; D004791:Enzyme Inhibitors / Q000009:adverse effects / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007211:Indoles / Q000009:adverse effects / Q000493:pharmacokinetics*; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008301:Maleimides / Q000009:adverse effects / Q000493:pharmacokinetics*; D006435:Renal Dialysis
D004791:Enzyme Inhibitors; D007211:Indoles; C474461:LY 338522; D008301:Maleimides; C099154:ruboxistaurin