nd AUC of Exviera 250 mg twice daily with ombitasvir/paritaprevir/ritonavir 25 mg/150 mg/100 mg once daily following multiple doses with food in healthy volunteers.
Table 16. Geometric mean Cmax, AUC of multiple doses of Exviera 250 mg twice daily and ombitasvir/paritaprevir/ritonavir 25 mg/150 mg/100 mg once daily with food in healthy volunteers
Absorption
Dasabuvir was absorbed after oral administration with mean Tmax of approximately 4 to 5 hours. Dasabuvir exposures increased in a dose proportional manner and accumulation is minimal. Pharmacokinetic steady state for dasabuvir when coadministered with ombitasvir/paritaprevir/ritonavir is achieved after approximately 12 days of dosing.
Effects of food
Dasabuvir should be administered with food. All clinical trials with dasabuvir have been conducted following administration with food.
Food increased the exposure (AUC) of dasabuvir by up to 30% relative to the fasting state. The increase in exposure was similar regardless of meal type (e.g., high-fat versus moderate-fat) or calorie content (approximately 600 kcal versus approximately 1000 kcal). To maximise absorption, Exviera should be taken with food without regard to fat or calorie content.
Distribution
Dasabuvir is highly bound to plasma proteins. Plasma protein binding is not meaningfully altered in patients with renal or hepatic impairment. The blood to plasma concentration ratios in human ranged from 0.5 to 0.7 indicating that dasabuvir was preferentially distributed in the plasma compartment of whole blood. Dasabuvir was greater than 99.5%, and M1 major metabolite of dasabuvir was 94.5% bound to human plasma proteins over a concentration range of 0.05 to 5 μg/mL. At steady-state the exposures ratio of M1 to dasabuvir is approximately 0.6. Taking into account the protein binding and in vitro activity of M1 against HCV genotype 1, its contribution to efficacy is expected to be similar to that of dasabuvir. In addition, M1 is a substrate of the hepatic uptake transporters OATP family and OCT1 and thus, the hepatocyte concentration and thereby contribution to efficacy, may be larger than dasabuvir.
Biotransformation
Dasabuvir is predominantly metabolised by CYP2C8 and to a lesser extent by CYP3A. Following a 400 mg 14C-dasabuvir dose in humans, unchanged dasabuvir was the major component (approximately 60%) of drug related radioactivity in plasma. Seven metabolites were identified in plasma. The most abundant plasma metabolite was M1, which represented 21% of drug-related radioactivity (AUC) in circulation following single dose; it's formed via oxidative metabolism predominantly by CYP2C8.
Elimination
Following dosing of dasabuvir with ombitasvir/ paritaprevir /ritonavir, mean plasma half-life of dasabuvir was approximately 6 hours. Following a 400 mg 14C-dasabuvir dose, approximately 94% of the radioactivity was recovered in faeces with limited radioactivity (approximately 2%) in urine. Unchanged dasabuvir accounted for 26.2% and M1 for 31.5% of the total dose in faeces. M1 is mainly cleared through direct biliary excretion with the contribution of UGT-mediated glucuronidation and, to a small extent, oxidative metabolism.
Dasabuvir does not inhibit organic anion transporter (OAT1) in vivo and is not expected to inhibit organic cation transporters (OCT2), organic anion transporters (OAT3), or multidrug and toxin extrusion proteins (MATE1 and MATE2K) at clinically relevant concentrations; therefore, Exvi |
