Steady-state pharmacokinetics of darunavir/ritonavir and pitavastatin when co-administered to healthy adult volunteers.
BACKGROUND
The treatment of hyperlipidaemia in human immunodeficiency virus (HIV)-infected patients has become increasingly important. However, treatment options are limited because of the drug-drug interaction between certain statins and HIV medications metabolized by cytochrome P450 (CYP) enzymes.


OBJECTIVE
The primary objective was to investigate the steady-state pharmacokinetics of pitavastatin when co-administered with darunavir/ritonavir. The secondary objective was to investigate the steady-state pharmacokinetics of both darunavir and ritonavir when co-administered with pitavastatin.


METHODS
This was a single-centre, open-label, multi-dose, fixed-sequence study in HIV seronegative healthy volunteers. Pitavastatin 4 mg was administered once daily on days 1-5 and on days 12-16, and darunavir 800 mg/ritonavir 100 mg once daily on days 6-16. Pharmacokinetic blood sampling was performed on days 5, 11 and 16. No significant interaction was concluded if the 90 % confidence intervals (CIs) of the geometric mean ratios (GMRs) for total exposure [i.e. the area under the plasma concentration-time curve over a dosing interval at steady state (AUC(0-τ))] and for peak exposure [i.e. the maximum plasma concentration (C(max))] of the two treatments were within the 80-125 % range.


RESULTS
Twenty-eight subjects (mean age 30.5 years) were enrolled, and pharmacokinetic data were available for 27 subjects. For pitavastatin, the GMRs and 90 % CIs for the AUC(0-τ) and C(max) ratios with co-administration were 0.74 (0.69-0.80) and 0.96 (0.84-1.09), respectively. For both darunavir and ritonavir, the 90 % CIs for the AUC(0-τ) and C max ratios were within 80-125 % with pitavastatin co-administration. No significant safety issues were reported.


CONCLUSIONS
Darunavir/ritonavir decreased total exposure to pitavastatin by 26 %, while peak exposures were similar. Pitavastatin did not influence the pharmacokinetics of darunavir or ritonavir. There is limited interaction between pitavastatin and darunavir/ritonavir.
Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, DC 0545, Indianapolis, IN, 46285, USA, yucy@lilly.com.
Christine Y
CY
Yu
Stuart E
SE
Campbell
Craig A
CA
Sponseller
David S
DS
Small
Matthew M
MM
Medlock
Roger E
RE
Morgan
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000069454:Darunavir; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D011804:Quinolines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019438:Ritonavir / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013449:Sulfonamides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D055815:Young Adult
D011804:Quinolines; D013449:Sulfonamides; C108475:pitavastatin; D019438:Ritonavir; D000069454:Darunavir