Plasma concentrations of the HIV-protease inhibitor lopinavir are suboptimal in children aged 2 years and below.
BACKGROUND
Lopinavir/ritonavir (LPV/r) has been licensed for the treatment of HIV-infected children >6 months in the US and >2 years in the EU. Limited LPV paediatric pharmacokinetic data are available. We studied LPV pharmacokinetics to determine whether the recommended dose (230/57.5 mg/m2 twice daily) results in optimal LPV exposure in all age groups. Virological efficacy was a secondary objective.


METHODS
HIV-1-infected children who started treatment with LPV/r and two nucleoside reverse transcriptase inhibitors underwent a 12-h pharmacokinetic curve. LPV plasma concentrations were determined with a validated HPLC method with UV detection. If Cmin was <1.0 mg/l LPV/r dose was increased by 33%. Plasma trough levels were drawn subsequently. HIV-1 RNA was followed-up until week 48.


RESULTS
A total of 23 children were included (seven girls; 16 boys), with a median (range) age of 5.6 (0.4-13.2) years. Mean (+/-SD) AUC0-12h, Cmax and Cmin of LPV were 75.3 (+/-33.7) mg/l.h, 9.33 (+/-3.27) mg/l and 3.68 (+/-2.48) mg/l, respectively, which is similar to previously published data. Interindividual variability was large. Cmin was inadequate in 7/23 children. Significantly more children <2 years had inadequate Cmin compared with children >2 years. Dose increase to +/-300/75 mg/m2 LPV/r led to Cmin >1.0 mg/l. The studied regimen provided excellent viral suppression for naive and pretreated patients.


CONCLUSIONS
Mean LPV pharmacokinetic parameters in these HIV-infected children are similar to published data, but exposure is significantly reduced in children <2 years. Prospective pharmacokinetic studies using 300/75 mg/m2 LPV/r in this age population are urgently warranted.
Erasmus MC-Sophia Children's Hospital, Rotterdam, the Netherlands.
Gwenda
G
Verweel
David M
DM
Burger
Nancy L
NL
Sheehan
Alina S
AS
Bergshoeff
Adilia
A
Warris
Linda C
LC
van der Knaap
Gertjan
G
Driessen
Ronald
R
de Groot
Nico G
NG
Hartwig
D000293:Adolescent; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007223:Infant; D061466:Lopinavir; D008297:Male; D011744:Pyrimidinones / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use; D012367:RNA, Viral / Q000097:blood; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use; D016896:Treatment Outcome
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D061466:Lopinavir