ABSTRACT
In HBV/HIV-coinfected patients, the risk of end-stage liver disease and death is increased. This open-label, prospective, pilot study evaluated abacavir/lamivudine/zidovudine twice daily plus tenofovir once daily in HBV/HIV-coinfected antiretroviral-naïve subjects. Nine adults (8 males) enrolled, with baseline mean HIV-1 RNA = 4.5 log(10) copies/mL, HBV DNA = 9.0 log(10) copies/mL, and median CD4 count =158 cells/mm(3). No subject had baseline ALT >5x ULN.SIX SUBJECTS COMPLETED THE STUDY: 1 withdrew due to non-treatment-related toxoplasmosis and 2 were lost-to-follow-up. At week 48, 100% (6/6) of remaining subjects had ≥2 log(10) decrease in HBV DNA, and 100% (6/6) and 83% (5/6) had HIV-1 RNA <400 and <50 copies/mL, respectively. Median change from baseline in CD4 count was 157 cells/mm(3). One subject experienced treatment-related grade 3 leukopenia. These results demonstrate that abacavir/lamivudine/zidovudine and tenofovir were well tolerated with sustained HIV-1 and HBV antiviral activity through 48 weeks in HBV/HIV-coinfected, antiretroviral-naïve subjects.
ABSTRACT
STUDY OBJECTIVE: To compare steady-state pharmacokinetics and pharmacodynamics of methadone enantiomers when coadministered with fosamprenavir 700 mg-ritonavir 100 mg twice/day. DESIGN: Open-label, single-sequence, two-period crossover, drug-interaction study. SETTING: Two university-affiliated research centers. SUBJECTS: Twenty-six opioid-dependent, methadone-maintained, healthy adults. INTERVENTION: Subjects received their usual daily dose of methadone alone for 4 days (period 1). Subjects then received the same daily dose of methadone plus fosamprenavir 700 mg-ritonavir 100 mg twice/day for 14 days (period 2). MEASUREMENTS AND MAIN RESULTS: Blood was collected on days 1-4 (period 1) and on days 11-14 (period 2) for plasma R- and S-methadone concentrations; amprenavir concentrations were assessed during period 2. Opioid-effect measures were assessed in each study period. Subjects served as their own controls for comparison of period 1 with period 2. Coadministration of fosamprenavir-ritonavir with methadone reduced plasma total R-methadone area under the plasma concentration-time curve over the dosing interval at steady state (AUC tau-ss) by 18%, maximum concentration at steady state (Cmax-ss) by 21%, and concentration at the end of the dosing interval at steady state (Ctau-ss) by 11%; time to reach Cmax-ss (Tmax) was delayed by 1.75 hours. Coadministration of fosamprenavir-ritonavir with methadone also reduced plasma total S-methadone AUC tau-ss and Cmax-ss by 43% each, Ctau-ss by 41%, and delayed Tmax by 0.85 hours. Fosamprenavir-ritonavir administered with methadone did not alter plasma amprenavir pharmacokinetics compared with historical control data; nor did it alter the unbound R-methadone at 2 and 6 hours after methadone dosing. Pharmacodynamic indexes remained essentially unchanged after adding fosamprenavir-ritonavir to methadone. No subject demonstrated opioid intoxication or withdrawal, or requested methadone dosage modification. CONCLUSION: No adjustment in the dosages of either methadone or fosamprenavir 700 mg-ritonavir 100 mg twice/day is required during coadministration, on the basis of the small reduction in total R-methadone exposure, no change in unbound R-methadone, no clinically important opioid effects, and no change in amprenavir exposure.
