Dose- and Formulation-Dependent Non-Linear Pharmacokinetic Model of Paritaprevir, a Protease Inhibitor for the Treatment of Hepatitis C Virus Infection: Combined Analysis from 12 Phase I Studies

Beyond Rule of Five and PROTACs in Modern Drug Discovery: Polarity Reducers, Chameleonicity, and the Evolving Physicochemical Landscape

Developing orally bioavailable drugs demands an understanding of absorption in early drug development. Traditional methods and physicochemical properties optimize absorption for rule of five (Ro5) compounds; beyond rule of five (bRo5) drugs necessitate advanced tools like the experimental measure of exposed polarity (EPSA) and the AbbVie multiparametric score (AB-MPS). Analyzing AB-MPS and EPSA against ∼1000 compounds with human absorption data and ∼10,000 AbbVie tool compounds (∼1000 proteolysis targeting chimeras or PROTACs, ∼7000 Ro5s, and ∼2000 bRo5s) revealed new patterns of physicochemical trends. We introduced a high-throughput "polarity reduction" descriptor: ETR, the EPSA-to-topological polar surface area (TPSA) ratio, highlights unique bRo5 and PROTAC subsets for specialized drug design strategies for effective absorption. Our methods and guidelines refine drug design by providing innovative in vitro approaches, enhancing physicochemical property optimization, and enabling accurate predictions of intestinal absorption in the complex bRo5 domain.

Pharmacokinetic Interactions and Safety of Coadministration of Glecaprevir and Pibrentasvir in Healthy Volunteers

BACKGROUND AND OBJECTIVE

Glecaprevir and pibrentasvir are pangenotypic direct-acting antiviral agents for the treatment of chronic hepatitis C virus infection. The aim of the present study was to evaluate the drug-drug interaction and safety of glecaprevir and pibrentasvir coadministration in healthy volunteers.

METHODS

In this open-label, randomized, multiple-dose, Phase 1 study in 72 subjects, glecaprevir (100-1200 mg once daily) and pibrentasvir (40-200 mg once daily) were administered alone for 7 days and then in combination for another 7 days. Intensive blood sampling was performed on Days 1, 7, 8, and 14, and pharmacokinetic interactions were assessed using a repeated measures analysis of glecaprevir and pibrentasvir maximum plasma concentration (C _max) and area under the curve (AUC).

RESULTS

Coadministration of glecaprevir 400 mg increased pibrentasvir 120 and 40 mg steady-state C _max and AUC values to 2.9-6.3-fold, and coadministration of glecaprevir 700 mg increased pibrentasvir 160 mg steady-state C _max and AUC₂₄ values to up to sevenfold of the values when pibrentasvir was administered alone. Glecaprevir C _max and AUC values during coadministration were less than 1.5-fold of the values when glecaprevir was administered alone. The combination of glecaprevir and pibrentasvir at doses up to 400 mg was well tolerated by the healthy subjects in this study. High glecaprevir exposures at 700 and 1200 mg were associated with grade 2/3 elevations in alanine aminotransferase, aspartate aminotransferase, and/or bilirubin.

CONCLUSIONS

Coadministration of pibrentasvir 120 mg with glecaprevir doses up to 400 mg resulted in increases in pibrentasvir exposures without significant changes in glecaprevir exposures in the absence of any clinically significant laboratory abnormalities.

Population Pharmacokinetics of Paritaprevir, Ombitasvir, and Ritonavir in Japanese Patients with Hepatitis C Virus Genotype 1b Infection

BACKGROUND AND OBJECTIVE

Hepatitis C virus (HCV) infection is of considerable clinical concern in Japan. We modeled the population pharmacokinetics of an oral interferon-free, direct-acting antiviral agent (DAA) regimen (i.e., the 2D regimen) recently approved for the treatment of chronic HCV genotype 1 infection as a new option for affected Japanese patients.

METHODS

Using data from a phase III clinical trial (GIFT-I) that enrolled Japanese patients with HCV genotype 1b infection, population pharmacokinetic models were developed for the drugs that comprise the 2D regimen: paritaprevir, ombitasvir, and ritonavir. Demographic and clinical covariates with potential to influence 2D pharmacokinetics were evaluated for their effects on drug exposures. Proposed models were assessed using goodness-of-fit plots, visual predictive checks, and bootstrap evaluations.

RESULTS

One-compartment models with first-order absorption and elimination adequately described the population pharmacokinetics of paritaprevir, ombitasvir, and ritonavir. On average, patients with cirrhosis had approximately 95-145 % higher, 19-24 % lower, and 58-68 % higher exposures of paritaprevir, ombitasvir, and ritonavir, respectively. Female patients had 58-81 % higher ombitasvir exposures, whereas patients with mild renal impairment (creatinine clearance 75 mL/min) had 9-14 % higher ombitasvir exposures than did patients with normal renal function (creatinine clearance 105 mL/min). The DAA exposure values were comparable between responders and non-responders.

CONCLUSION

Population pharmacokinetic modeling did not reveal any patient-related or clinical parameters that would require dose adjustment of the 2D regimen when used for the treatment of HCV genotype 1b infection in Japanese patients.

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_24,ss) 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_24,ss 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_24,ss 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_24,ss 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.