Rilpivirine Pharmacokinetics Without and With Darunavir/Ritonavir Once Daily in Adolescents and Young Adults

Foca, M.; Yogev, R.; Wiznia, A.; Hazra, R.; Jean-Philippe, P.; Graham, B.; Britto, P.; Carey, V. J.; King, J.; Acosta, E. P.; Cressey, T. R.

Pediatr Infect Dis J. 2016 May 18; 35(9):e271-4

Abstract

BACKGROUND: Rilpivirine (RPV), a recently developed, once daily human immunodeficiency virus non-nucleoside reverse transcriptase inhibitor, is not currently approved for pediatric patients, but is sometimes prescribed for adolescents with multiple treatment failures, for regimen simplification or to minimize toxicity. Darunavir/ritonavir (DRV/r) administered once daily is also increasingly used in adolescents and may alter RPV pharmacokinetics (PK). We evaluated the PK interactions between RPV and DRV/r once daily in adolescents and young adults. METHODS: Human immunodeficiency virus-infected subjects 12 to <24 years old receiving a stable background therapy including RPV 25 mg once daily without or combined with DRV/r 800/100 mg once daily were enrolled. Intensive 24-hour blood sampling was performed, and PK indices were determined using noncompartmental analysis. Protocol-defined target drug exposure ranges based on adult data were used to assess the adequacy of each regimen. RESULTS: Fifteen subjects receiving RPV without and 14 subjects with DRV/r were enrolled. When dosed without DRV/r, the RPV geometric mean (90% confidence interval) for RPV AUC0-24, Cmax and C24 h were 2.38 mug h/mL (1.92-2.94), 0.14 mug/mL (0.12-0.18) and 0.07 mug/mL (0.03-0.10), respectively, similar to adult values. RPV concentrations were significantly increased with concomitant DRV/r use: RPV AUC24, Cmax and C24 h were 6.74 mug h/mL (4.89-9.28), 0.39 mug/mL (0.27-0.57) and 0.23 mug/mL (0.17-0.32), respectively, well above the target ranges based on adult data. DRV/r PK was not affected by coadministration of RPV. CONCLUSIONS: RPV PK in this adolescent population was similar to adults when dosed without DRV/r. DRV/r coadministration increased RPV exposure 2- to 3-fold, indicating that drug-related side effects should be closely monitored.

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