Quantifying VMAT2 target occupancy at effective valbenazine doses and comparing to a novel VMAT2 inhibitor: a translational PET study.

Positron emission tomography (PET) is frequently used to obtain target occupancy (%TO) of central nervous system (CNS) drug candidates during clinical development. Obtaining %TO with PET can be particularly powerful when the %TO associated with efficacy is known for a protein target. Using the radiotracer [F]AV-133, the relationship between plasma concentration (PK) and %TO of NBI-750142, an experimental inhibitor of the vesicular monoamine transporter type 2 (VMAT2) was obtained in both nonhuman primate (NHP) and human.

Crinecerfont, a CRF1 Receptor Antagonist, Lowers Adrenal Androgens in Adolescents With Congenital Adrenal Hyperplasia.

Context: Crinecerfont, a corticotropin-releasing factor type 1 receptor antagonist, has been shown to reduce elevated adrenal androgens and precursors in adults with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD), a rare autosomal recessive disorder characterized by cortisol deficiency and androgen excess due to elevated adrenocorticotropin.

Objective: To evaluate the safety, tolerability, and efficacy of crinecerfont in adolescents with 21OHD CAH.

Methods: This was an open-label, phase 2 study (NCT04045145) at 4 centers in the United States.

Crinecerfont Lowers Elevated Hormone Markers in Adults With 21-Hydroxylase Deficiency Congenital Adrenal Hyperplasia.

Context: Classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD) is characterized by impaired cortisol synthesis and excess androgen production. Corticotropin-releasing factor type 1 receptor (CRF1R) antagonism may decrease adrenal androgen production.

Objective: This work aimed to evaluate the safety, tolerability, and efficacy of crinecerfont (NBI-74788), a selective CRF1R antagonist, in 21OHD.

Evaluation of the potential effect of dacomitinib, an EGFR tyrosine kinase inhibitor, on ECG parameters in patients with advanced non-small cell lung cancer.

Purpose The study evaluated the potential effect of dacomitinib, a small molecule epidermal growth factor receptor (EGFR) inhibitor, on the electrocardiogram (ECG) parameters in adult patients with advanced non-small cell lung cancer enrolled in a multicenter, open-label, phase 2 study. Methods Patients received dacomitinib for six doses of 45 mg every 12 h in a 7-day lead-in cycle (cycle 0), then 60 mg every 12 h for six doses in a 14-day cycle (cycle 1). Clock time-matched triplicate ECGs were performed at 0, 2, 4, 6, 8 and 10 h on day 1 (baseline) and day 4 of cycle 0, and prior to dose on days 1 and 4 of cycle 1.

Phase 2 study of intermittent pulse dacomitinib in patients with advanced non-small cell lung cancers.

Background: Dacomitinib is a second-generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). Pre-clinical data suggest that intermittent pulsatile dosing of dacomitinib may result in inhibition of EGFR T790M.

Methods: We evaluated safety, pharmacokinetics and efficacy of intermittent pulsatile dacomitinib in both molecularly unselected patients and patients with lung cancers harboring EGFR T790M (Clinical Trial Registration Number NCT01858389).

Evaluation of the effect of new formulation, food, or a proton pump inhibitor on the relative bioavailability of the smoothened inhibitor glasdegib (PF-04449913) in healthy volunteers.

Purpose: This phase I open-label study investigated the oral bioavailability of two novel maleate salt-based glasdegib (PF-04449913) tablet formulations (small- and large-particle size) relative to the current clinical formulation (diHCl salt-based). In addition, the effect of a gastric pH-altering agent (rabeprazole) and food on the pharmacokinetics of the large-particle size formulation of glasdegib were evaluated. The pharmacokinetics of glasdegib oral solution was also assessed.

Phase 1 study to investigate the pharmacokinetic properties of dacomitinib in healthy adult Chinese subjects genotyped for CYP2D6.

1. This study aimed to characterise the pharmacokinetics of dacomitinib, a pan-human epidermal growth factor receptor tyrosine kinase inhibitor, and its metabolite, PF-05199265, in healthy Chinese subjects. 2.

Impact of a planned dose interruption of dacomitinib in the treatment of advanced non-small-cell lung cancer (ARCHER 1042).

Objectives: Dacomitinib is a pan-HER inhibitor for advanced non-small-cell lung cancer (NSCLC). We explored the impact of a planned 4-day dacomitinib dose interruption on plasma exposure of dacomitinib and adverse events (AEs) of interest in Cohort III of the ARCHER 1042 study.

Materials And Methods: Patients, treatment-naïve for advanced NSCLC with EGFR activating mutations, received oral dacomitinib 45mg QD (once daily).

A Phase I Clinical Trial and Independent Patient-Derived Xenograft Study of Combined Targeted Treatment with Dacomitinib and Figitumumab in Advanced Solid Tumors.

This phase I, open-label, single-arm trial assessed the safety and tolerability of dacomitinib-figitumumab combination therapy in patients with advanced solid tumors. A standard 3 + 3 dose escalation/de-escalation design was utilized. Starting doses were figitumumab 20 mg/kg administered intravenously once every 3 weeks and dacomitinib 30 mg administered orally once daily.

Investigation of the impact of hepatic impairment on the pharmacokinetics of dacomitinib.

Dacomitinib (PF-00299804) is a small-molecule inhibitor of the tyrosine kinases human epidermal growth factor receptor-1 (HER1; epidermal growth factor receptor, EGFR), HER2, and HER4 currently being developed for the treatment of lung cancer with sensitizing mutations in EGFR or refractory to EGFR-directed treatment. Dacomitinib is largely metabolized by the liver through oxidative and conjugative metabolism; therefore, determination of the impact of varying degrees of hepatic impairment on the pharmacokinetics (PK) of dacomitinib was warranted to ensure patient safety. In this phase I, open-label, parallel-group study, a single dose of dacomitinib was administered to healthy volunteers and to subjects with mild or moderate liver dysfunction, as determined by Child-Pugh classification.

Safety and efficacy of dacomitinib in korean patients with KRAS wild-type advanced non-small-cell lung cancer refractory to chemotherapy and erlotinib or gefitinib: a phase I/II trial.

Introduction: Dacomitinib (PF-00299804), an irreversible pan-human epidermal growth factor receptor ([HER]-1/EGFR, HER-2, and HER-4) tyrosine kinase inhibitor, demonstrated antitumor activity in Western patients with non-small-cell lung cancer (NSCLC) at a dose of 45 mg once daily. We report data from a phase I/II, multicenter, open-label study of Korean patients with refractory KRAS wild-type adenocarcinoma NSCLC (defined as patients with evidence of disease progression during or within 6 months of treatment with chemotherapy and gefitinib or erlotinib).

Methods: The phase I dose-finding portion identified the recommended phase II dose (RP2D) in Korean patients, evaluated safety, and characterized the pharmacokinetics of dacomitinib.

A phase I open-label study to investigate the potential drug-drug interaction between single-dose dacomitinib and steady-state paroxetine in healthy volunteers.

Dacomitinib is currently in development for the treatment of non-small cell lung cancer. Formation of the major circulating metabolite (PF-05199265) is mediated by cytochrome P450 (CYP) 2D6 and CYP2C9. This phase I, single fixed-sequence, two-period study evaluated the effect of paroxetine, a CYP2D6 inactivator, on dacomitinib pharmacokinetics in healthy volunteers who were extensive CYP2D6 metabolizers.

Evaluation of the use of static and dynamic models to predict drug-drug interaction and its associated variability: impact on drug discovery and early development.

Simcyp, a population-based simulator, is widely used for evaluating drug-drug interaction (DDI) risks in healthy and disease populations. We compare the prediction performance of Simcyp with that of mechanistic static models using different types of inhibitor concentrations, with the aim of understanding their strengths/weaknesses and recommending the optimal use of tools in drug discovery/early development. The inclusion of an additional term in static equations to consider the contribution of hepatic first pass to DDIs (AUCR(hfp)) has also been examined.

Investigation of the micellar effect of pluronic P85 on P-glycoprotein inhibition: cell accumulation and equilibrium dialysis studies.

The objective of this study was: (1) to characterize the P-gp inhibitory effect of different concentrations of Pluronic P85 on anti-HIV-1 drug cellular accumulation, and (2) to investigate the relationship between cellular accumulation and free fraction of drug. Cellular accumulation studies in MDCKII-WT and MDCKII-MDR1 cell monolayers showed a biphasic dose response characterized by decline in accumulation at Pluronic concentrations greater than the CMC. This phenomenon was independent of the inhibition of P-gp efflux by Pluronic.

Substrate-dependent breast cancer resistance protein (Bcrp1/Abcg2)-mediated interactions: consideration of multiple binding sites in in vitro assay design.

In vitro assays are frequently used for the screening of substrates and inhibitors of transporter-mediated efflux. Examining directional flux across Madin-Darby canine kidney (MDCK) II cell monolayers that overexpress a transporter protein is particularly useful in identifying whether or not a candidate compound is an inhibitor or substrate for that transport system. Studies that use a single substrate or inhibitor in competition assays can be challenging to interpret because of the possible multiple mechanisms involved in substrate/inhibitor-protein interactions.

Investigation of the role of breast cancer resistance protein (Bcrp/Abcg2) on pharmacokinetics and central nervous system penetration of abacavir and zidovudine in the mouse.

Many anti-human immunodeficiency virus 1 nucleoside reverse-transcriptase inhibitors have low central nervous system (CNS) distribution due in part to active efflux transport at the blood-brain barrier. We have previously shown that zidovudine (AZT) and abacavir (ABC) are in vitro substrates for the efflux transport protein breast cancer resistance protein (Bcrp) 1. We evaluated the influence of Bcrp1 on plasma pharmacokinetics and brain penetration of zidovudine and abacavir in wild-type and Bcrp1-deficient (Bcrp1-/-) FVB mice.

P-glycoprotein-mediated active efflux of the anti-HIV1 nucleoside abacavir limits cellular accumulation and brain distribution.

P-glycoprotein (P-gp)-mediated efflux at the blood-brain barrier has been implicated in limiting the brain distribution of many anti-HIV1 drugs, primarily protease inhibitors, resulting in suboptimal concentrations in this important sanctuary site. The objective of this study was to characterize the interaction of abacavir with P-gp and determine whether P-gp is an important mechanism in limiting abacavir delivery to the central nervous system (CNS). In vitro and in vivo techniques were employed to characterize this interaction.

Abcg2/Bcrp1 mediates the polarized transport of antiretroviral nucleosides abacavir and zidovudine.

The bioavailability and targeted distribution of abacavir (ABC) and zidovudine (AZT) to viral reservoirs may be influenced by efflux transporters. The purpose of this study was to characterize the interaction of these nucleoside reverse transcriptase inhibitors with the Abcg2/Bcrp1 transporter, the murine homolog of human breast cancer resistance protein (BCRP), using a Bcrp1-transfected Madin-Darby canine kidney II cell model. Intracellular accumulation of ABC and AZT was significantly reduced by approximately 90% and approximately 70%, respectively, in Bcrp1-transfected cells compared with the wild-type cells.