Effect of co-medications on paritaprevir, ritonavir, ombitasvir, dasabuvir and ribavirin pharmacokinetics: analysis of data from seven Phase II/III trials.

Background: The three drug direct-acting antiviral regimen (3D regimen) of ombitasvir, paritaprevir/ritonavir and dasabuvir, with and without ribavirin, was evaluated in one Phase II trial and six Phase III trials in over 2,300 HCV genotype-1-infected patients. Patients continued taking their protocol-permitted co-medications while receiving the 3D ± ribavirin regimen. The effects of the co-medications on exposures of the 3D regimen and ribavirin were examined.

Methods: Population pharmacokinetic model-predicted steady-state area under the curve (AUC) values were evaluated in the presence/absence of the co-medications. Interactions resulting in a greater than 50% reduction or 100% increase in an AUC value were examined as covariates for an effect on apparent clearance (CL/F).

Results: More than 1,200 co-medications belonging to 15 drug classes and/or 19 enzyme and transporter inhibitor and/or inducer categories were used concomitantly with the 3D regimen in the trials. Approximately 1,500 patients (65%) in Phase III trials received two or more co-medications from multiple drug classes or categories. No co-medication class/category decreased or increased ombitasvir, dasabuvir, ritonavir or ribavirin AUC by more than half or twofold, respectively. Opioids, antipsychotics, anti-epileptics, antidiabetics and non-ethinyl estradiol-containing hormone replacement therapies appeared to have an effect (AUC ratio ≤0.5 or ≥2.0) on paritaprevir exposures. However, when these classes were included in the paritaprevir population pharmacokinetic model, only opioids and antidiabetics had a statistically significant effect on CL/F, but with no clinically meaningful increase in exposures (≤55%).

Conclusions: No dose adjustment is necessary for the 3D ± ribavirin regimen when used with the co-medications included in this analysis as there were no clinically meaningful effects on exposures of the DAAs.