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This paper describes the pharmacokinetics (PK), mass balance, metabolic profiling, and safety of talazoparib after a single oral dose of

This study aims at evaluating the utility of the population pharmacokinetics approach in therapeutic protein drug-drug-interaction (DDI) assessment. Simulations were conducted for 2 representative victim drugs, methotrexate and trastuzumab, using a parallel-group design with and without the interaction drug. The effect of a perpetrator on the exposure of the victim drug is described as the ratio of clearance/apparent clearance of the victim drug given with or without the perpetrator. The power of DDI assessment was calculated as the percentage of runs with 90% confidence interval of the estimated DDI effect within 80% to 125% for the scenarios of no DDI, benchmarked with the noncompartmental approach with intensive sampling. The impact of the number of subjects, the number of sampling points per subject, sampling time error, and model misspecification on the power of DDI determination were evaluated. Results showed that with equal numbers of subjects in each arm, the population pharmacokinetics approach with sparse sampling may need about the same or a higher number of subjects compared to a noncompartmental approach in order to achieve similar power. Increasing the number of subjects, even if only in the study drug alone arm, can increase the power. Sampling or dosing time error had notable impacts on the power for methotrexate but not for trastuzumab. Model misspecification had no notable impacts on the power for trastuzumab. Overall, the population pharmacokinetics approach with sparse sampling built in phase 2/3 studies allows appropriate DDI assessment with adequate study design and analysis and can be considered as an alternative to dedicated DDI studies.

Palbociclib is an orally available CDK4/6 inhibitor. In humans, palbociclib undergoes metabolism mediated primarily by CYP3A and SULT2A1, and it is also a weak time-dependent CYP3A inhibitor. The objectives of the current study are to (1) develop a physiologically based pharmacokinetic (PBPK) model of palbociclib based on the in silico, in vitro, and in vivo pharmacokinetic data of palbociclib, (2) verify the PBPK model with clinical drug-drug interaction (DDI) results of palbociclib with strong CYP3A inhibitor (itraconazole), inducer (rifampin), and a sensitive CYP3A substrate (midazolam), and (3) predict the DDI risk of palbociclib with moderate/weak CYP3A inhibitors. The developed PBPK model adequately described the observed pharmacokinetics of palbociclib after administration of a single oral or intravenous dose of palbociclib. The model-predicted DDIs of palbociclib with itraconazole, rifampin, and midazolam were consistent with the observed DDIs, with the discrepancies of the predicted vs observed AUCR and C

E2212, a novel γ-secretase modulator, is under development for the treatment of Alzheimer's disease. The safety, tolerability, pharmacokinetics, and pharmacodynamics of single ascending oral doses (10-250 mg, double-blind, placebo-controlled, randomized) of E2212 were evaluated. In this phase I clinical trial, E2212 was found to be well tolerated in single doses. Maximum tolerated dose was not achieved up to 250 mg. Most AEs were mild to moderate in severity with no identifiable dose related pattern. There were no clinically significant findings on physical and ophthalmologic examinations as well as vital signs, laboratory, ECG and C-SSRS assessments. E2212 was rapidly absorbed, with median tmax values ranging from 0.5 to 1.0 h. E2212 exhibited biphasic disposition with the terminal t1/2 of 12.5-19.0 h. Renal excretion was the minor pathway for E2212 elimination. Increased PD response (reduction in plasma concentrations of Aβ(x-42)) was observed with increasing doses. The maximum PD response was observed in the highest dose 250 mg cohort, with ΔAUAC(0-24 h) of 44.1% and Amax of 53.6%. These results support further clinical development of E2212.