Assessment of the Effects of Abrocitinib on the Pharmacokinetics of Probe Substrates of Cytochrome P450 1A2, 2B6 and 2C19 Enzymes and Hormonal Oral Contraceptives in Healthy Individuals.

BACKGROUND AND OBJECTIVE: Abrocitinib is an oral small-molecule Janus kinase (JAK)-1 inhibitor approved for the treatment of moderate-to-severe atopic dermatitis. In vitro studies indicated that abrocitinib is a weak time-dependent inhibitor of cytochrome P450 (CYP) 2C19/3A and a weak inducer of CYP1A2/2B6/2C19/3A. To assess the potential effect of abrocitinib on concomitant medications, drug-drug interaction (DDI) studies were conducted for abrocitinib with sensitive probe substrates of these CYP enzymes. The impact of abrocitinib on hormonal oral contraceptives (ethinyl estradiol and levonorgestrel), as substrates of CYP3A and important concomitant medications for female patients, was also evaluated. METHODS: Three Phase 1 DDI studies were performed to assess the impact of abrocitinib 200 mg once daily (QD) on the probe substrates of: (1) 1A2 (caffeine), 2B6 (efavirenz) and 2C19 (omeprazole) in a cocktail study; (2) 3A (midazolam); and (3) 3A (oral contraceptives). RESULTS: After multiple doses of abrocitinib 200 mg QD, there is a lack of effect on the pharmacokinetics of midazolam, efavirenz and contraceptives. Abrocitinib increased the area under the concentration time curve from 0 to infinity (AUCinf) and the maximum concentration (Cmax) of omeprazole by approximately 189 and 134%, respectively. Abrocitinib increased the AUCinf of caffeine by 40% with lack of effect on Cmax. CONCLUSIONS: Based on the study results, abrocitinib is a moderate inhibitor of CYP2C19. Caution should be exercised when using abrocitinib concomitantly with narrow therapeutic index medicines that are primarily metabolized by CYP2C19 enzyme. Abrocitinib is a mild inhibitor of CYP1A2; however, the impact is not clinically relevant, and no general dose adjustment is recommended for CYP1A2 substrates. Abrocitinib does not inhibit CYP3A or induce CYP1A2/2B6/2C19/3A and does not affect the pharmacokinetics of contraceptives. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov registration IDs: NCT03647670, NCT05067439, NCT03662516.

Multivariate Assessment for Bioequivalence Based on the Correlation of Random Effect.

BACKGROUND AND OBJECTIVE: Bioequivalence tests are fundamental step in assessing the equivalence in bioavailability between a test and reference product. In practice, two separate linear mixed models (LMMs) with random subject effects, which have an area under the concentration-time curve (AUC) and the peak concentration (Cmax) as the responses, have become the gold standard for evaluating bioequivalence. Recently, Lee et al developed a multivariate hierarchical generalized linear model (HGLM) for several responses that modeled correlations among multivariate responses via correlated random effects. The objective of this study was to apply this multivariate analysis to the bioequivalence test in practice and to compare the performance of multivariate HGLM and separate LMMs. METHODS: Three pharmacokinetic datasets, fixed-dose combination (naproxen and esomeprazole), tramadol and fimasartan data were analyzed. We compared the 90% confidence interval (CI) for the geometric mean ratio (GMR) of a test product to a reference product using the multivariate HGLM and two conventional separate LMMs. RESULTS: We found that the 90% CIs for the GMRs of both AUC and Cmax from the multivariate HGLM were narrower than those from the separate LMMs: (0.843, 1.152) vs (0.825, 1.177) for Cmax of esomeprazole in fixed-dose combination data; (0.805, 0.931) vs (0.797, 0.941) for Cmax in tramadol data; (0.801, 1.501) vs (0.762, 1.578) for Cmax and (1.163, 1.332) vs (1.009, 1.341) for AUC in fimasartan data, consistent with the random subject effects from two separate LMMs being highly correlated in the three datasets (correlation coefficient r = 0.883; r = 0.966; r = 0.832). CONCLUSION: This multivariate HGLM had good performance in the bioequivalence test with multiple endpoints. This method would provide a more reasonable option to reduce the 90% CI by adding correlation parameters and thus an advantage especially in evaluating the bioequivalence of highly variable drugs with broad 90% CIs.

Assessment of Clinical Drug-Drug Interactions of Elagolix, a Gonadotropin-Releasing Hormone Receptor Antagonist.

Elagolix is an oral gonadotropin-releasing hormone receptor antagonist indicated for the management of endometriosis-associated pain and in combination with estradiol/norethindrone acetate indicated for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women. Elagolix coadministered with estradiol/norethindrone acetate is in late-stage development for the management of heavy menstrual bleeding associated with uterine fibroids. Based on the in vitro profile of elagolix metabolism and disposition, 9 drug-drug interaction (DDI) studies evaluating the victim and perpetrator characteristics of elagolix were conducted in 144 healthy volunteers. As a victim of cytochrome P450 (CYPs) and transporter-mediated DDIs, elagolix area under the curve (AUC) increased by ∼2-fold following coadministration with ketoconazole and by ∼5- and ∼2-fold with single and multiple doses of rifampin, respectively. As a perpetrator, elagolix decreased midazolam AUC (90% confidence interval) by 54% (50%-59%) and increased digoxin AUC by 32% (23%-41%). Elagolix decreased rosuvastatin AUC by 40% (29%-50%). No clinically significant changes in exposure on coadministration with sertraline or fluconazole occurred. A elagolix 150-mg once-daily regimen should be limited to 6 months with strong CYP3A inhibitors and rifampin because of the potential increase in bone mineral density loss, as described in the drug label. A 200-mg twice-daily regimen is recommended for no more than 1 month with strong CYP3A inhibitors and not recommended with rifampin. Elagolix is contraindicated with strong organic anion transporter polypeptide B1 inhibitors (eg, cyclosporine and gemfibrozil). Consider increasing the doses of midazolam and rosuvastatin when coadministered with elagolix, and individualize therapy based on patient response. Clinical monitoring is recommended for P-glycoprotein substrates with a narrow therapeutic window (eg, digoxin). Dose adjustments are not required for sertraline, fluconazole, bupropion (or any CYP2B6 substrate), or elagolix when coadministered.

Comparative assessment of the effects of bumped kinase inhibitors on early zebrafish embryo development and pregnancy in mice.

Bumped kinase inhibitors (BKIs) are effective against a variety of apicomplexan parasites. Fifteen BKIs with promising in vitro efficacy against Neospora caninum tachyzoites, low cytotoxicity in mammalian cells, and no toxic effects in non-pregnant BALB/c mice were assessed in pregnant mice. Drugs were emulsified in corn oil and were applied by gavage for 5 days. Five BKIs did not affect pregnancy, five BKIs exhibited ~15-35% neonatal mortality and five compounds caused strong effects (infertility, abortion, stillbirth and pup mortality). Additionally, the impact of these compounds on zebrafish (Danio rerio) embryo development was assessed by exposing freshly fertilised eggs to 0.2-50 µM of BKIs and microscopic monitoring of embryo development in a blinded manner for 4 days. We propose an algorithm that includes quantification of malformations and embryo deaths, and established a scoring system that allows the calculation of an impact score (Si) indicating at which concentrations BKIs visibly affect zebrafish embryo development. Comparison of the two models showed that for nine compounds no clear correlation between Si and pregnancy outcome was observed. However, the three BKIs affecting zebrafish embryos only at high concentrations (≥40 µM) did not impair mouse pregnancy at all, and the three compounds that inhibited zebrafish embryo development already at 0.2 µM showed detrimental effects in the pregnancy model. Thus, the zebrafish embryo development test has limited predictive value to foresee pregnancy outcome in BKI-treated mice. We conclude that maternal health-related factors such as cardiovascular, pharmacokinetic and/or bioavailability properties also contribute to BKI-pregnancy effects.

Safety assessment of metarrestin in dogs: A clinical candidate targeting a subnuclear structure unique to metastatic cancer cells.

Pancreatic cancer is a leading cause of cancer-related deaths in the U.S. Ninety percent of patients with stage IV pancreatic cancer die within one year of diagnosis due to complications of metastasis. A metastatic potential of cancer cells has been shown to be closely associated with formation of perinucleolar compartment (PNC). Metarrestin, a first-in-class PNC inhibitor, was evaluated for its toxicity, toxicokinetics, and safety pharmacology in beagle dogs following every other day oral (capsule) administration for 28 days to support its introduction into clinical trials. The study consisted of four dose groups: vehicle; 0.25, 0.75 and 1.50 mg/kg/dose. Metarrestin reached its maximum concentration in blood at 3 h (overall median Tmax) across all doses with a mean t1/2 over 168 h of 55.5 h. Dose dependent increase in systemic exposure (Cmax and AUClast) with no sex difference was observed on days 1 and 27. Metarrestin accumulated from Day 1 to Day 27 at all dose levels and in both sexes by an overall factor of about 2.34. No mortality occurred during the dosing period; however, treatment-related clinical signs of toxicity consisting of hypoactivity, shaking/shivering, thinness, irritability, salivation, abnormal gait, tremors, ataxia and intermittent seizure-like activity were seen in both sexes at mid and high dose groups. Treatment-related effects on body weight and food consumption were seen at the mid and high dose levels. Safety pharmacology study showed no treatment-related effects on blood pressure, heart rate, corrected QT, PR, RR, or QRS intervals, or respiratory function parameters (respiratory rate, tidal volume, minute volume). There were no histopathological changes observed, with the exception of transient thymic atrophy which was considered to be non-adverse. Based primarily on clinical signs of toxicity, the No Observed Adverse Effect Level (NOAEL) in dogs was considered to be 0.25 mg/kg metarrestin after every other day dosing for 28 days with a mean of male and female Cmax = 82.5 ng/mL and AUClast = 2521 h*ng/mL, on Day 27.

Critical Assessment of Pharmacokinetic Drug-Drug Interaction Potential of Tofacitinib, Baricitinib and Upadacitinib, the Three Approved Janus Kinase Inhibitors for Rheumatoid Arthritis Treatment.

The introduction of novel, small-molecule Janus kinase inhibitors namely tofacitinib, baricitinib and upadacitinib has provided an alternative treatment option for patients with rheumatoid arthritis outside of traditional drugs and expensive biologics. This review aimed to critically assess the drug-drug interaction potential of tofacitinib, baricitinib and upadacitinib and provide a balanced perspective for choosing the most appropriate Janus kinase inhibitor based on the needs of patients with rheumatoid arthritis including co-medications and renal/hepatic impairment status. Based on the critical assessment, all three approved Janus kinase inhibitors generally provide a favourable opportunity for co-prescription with a plethora of drugs. While cytochrome P450 3A4-related inhibition or induction altered the exposures (area under the curve) of tofacitinib and upadacitinib, it did not impact the exposure of baricitinib. Transporter drug-drug interaction studies revealed that the disposition of baricitinib was altered with certain transporter inhibitors as compared with either tofacitinib or upadacitinib. Adjustment of tofacitinib or baricitinib dosages but not that of upadacitinib is required with the progression of renal impairment from a mild to a severe condition. While the dosage of tofacitinib needs to be adjusted for patients with moderate hepatic impairment status, it is not the case for either baricitinib or upadacitinib. Assessment of the drug-drug interaction potential suggests that tofacitinib, baricitinib and upadacitinib generally show a favourable disposition with no perpetrator activity; however, as victim drugs, they show subtle pharmacokinetic differences that may be considered during polypharmacy. Moreover, careful choice of the three drugs could be made in patients with rheumatoid arthritis with varying degrees of renal/hepatic impairments.

An Assessment of Pharmacokinetic Interaction Between Lobeglitazone and Sitagliptin After Multiple Oral Administrations in Healthy Men.

PURPOSE: Patients with type 2 diabetes mellitus require strict blood glucose control, and combination therapy with a thiazolidinedione and dipeptidyl peptidase-4 inhibitors, such as lobeglitazone and sitagliptin, is one of the recommended treatments. The objective of this study was to investigate a possible pharmacokinetic interaction between lobeglitazone and sitagliptin after multiple oral administrations in healthy Korean men. METHODS: Two randomized, open-label, multiple-dose, 2-way crossover studies were conducted simultaneously in healthy men. In study 1, men were randomly assigned to 1 of 2 sequences, and 1 of the following treatments was administered in each period: 1 tablet of lobeglitazone sulfate (0.5 mg) once daily for 5 days and or 1 tablet each of lobeglitazone sulfate (0.5 mg) and sitagliptin (100 mg) once daily for 5 days. In study 2, men were also randomly assigned to 1 of 2 sequences and the treatments were as follows: 1 tablet of sitagliptin (100 mg) once daily for 5 days or 1 tablet each of sitagliptin (100 mg) and lobeglitazone sulfate (0.5 mg) once daily for 5 days. Serial blood samples were collected up to 48 h after dosing on the fifth day. Plasma drug concentrations were measured by LC-MS/MS. Pharmacokinetic parameters, including Cmax,ss and AUC0-τ , were determined by noncompartmental analysis. The geometric least-square mean (GLSM) ratios and associated 90% CIs of log-transformed Cmax,ss and AUC0-τ for separate or coadministration were calculated to evaluate pharmacokinetic interactions. FINDINGS: Nineteen men from study 1 and 17 from study 2 completed the pharmacokinetic sampling and were included in the analyses. The GLSM ratios of Cmax,ss and AUC0-τ were 0.9494 (95% CI, 0.8798-1.0243) and 1.0106 (95% CI, 0.9119-1.1198) for lobeglitazone (from study 1) and 1.1694 (95% CI, 1.0740-1.2732) and 1.0037 (95% CI, 0.9715-1.0369) for sitagliptin (from study 2), respectively. IMPLICATIONS: Except for the slight 17% increase in the sitagliptin Cmax,ss value, the pharmacokinetic parameters of lobeglitazone and sitagliptin met the pharmacokinetic equivalent criteria when administered separately or in combination. The increase in Cmax of sitagliptin when coadministered with lobeglitazone would not be clinically significant in practice. ClinicalTrials.gov Identifier: NCT02824874 and NCT02827890.

Assessment of Pharmacokinetics and Metabolism Profiles of SCH 58261 in Rats Using Liquid Chromatography-Mass Spectrometric Method.

5-Amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c) pyrimidine (SCH 58261) is one of the new chemical entities that has been developed as an adenosine A2A receptor antagonist. Although SCH 58261 has been reported to be beneficial, there is little information about SCH 58261 from a drug metabolism or pharmacokinetics perspective. This study describes the metabolism and pharmacokinetic properties of SCH 58261 in order to understand its behaviors in vivo. Rats were used as the in vivo model species. First, an LC-MS/MS method was developed for the determination of SCH 58261 in rat plasma. A GastroPlus™ simulation, in vitro microsomal metabolic stability, and bile duct-cannulated studies were also performed to understand its pharmacokinetic profile. The parameter sensitivity analysis of GastroPlus™ was used to examine the factors that influence exposure when the drug is orally administered. The factors are as follows: permeability, systemic clearance, renal clearance, and liver first-pass effect. In vitro microsomal metabolic stability indicates how much the drug is metabolized. The extrapolated hepatic clearance value of SCH 58261 was 39.97 mL/min/kg, indicating that the drug is greatly affected by hepatic metabolism. In vitro microsomal metabolite identification studies revealed that metabolites produce oxidized and ketone-formed metabolites via metabolic enzymes in the liver. The bile duct-cannulated rat study, after oral administration of SCH 58261, showed that a significant amount of the drug was excreted in feces. These results imply that the drug is not absorbed well in the body after oral administration. Taken together, SCH 58261 showed quite a low bioavailability when administered orally and this was likely due to significantly limited absorption, as well as high metabolism in vivo.

Cost-Neutral Optimization of Pazopanib Exposure by Splitting Intake Moments: A Prospective Pharmacokinetic Study in Cancer Patients.

BACKGROUND AND OBJECTIVE: Pazopanib is an oral tyrosine kinase inhibitor used in the treatment of renal cell carcinoma and soft-tissue sarcoma. At the approved dose of 800 mg once daily (QD), 16-20% of patients are being underdosed and at risk of decreased efficacy. This study aimed to show whether splitting intake moments, as a cost-neutral alternative to a dose increase, leads to an increased exposure. METHODS: We performed a cross-over trial comparing the pharmacokinetics of pazopanib 800 mg QD with pazopanib 400 mg twice daily. Pharmacokinetic sampling was performed at steady-state for both dosing schedules. RESULTS: Nine evaluable patients were included. At the 800 mg QD dosing schedule, median minimum plasma concentration (Cmin), area under the concentration-time curve from 0 to 24 h (AUC0-24h), and maximum plasma concentration (Cmax) were 23.2 mg/L (interquartile range 18.5-27.6), 773 mg h/L (557-1009), and 40.6 mg/L (36.4-56.4) compared with 41.6 mg/L (30.5-55.8, p = 0.004), 942 mg h/L (885-1419, p = 0.027), and 50.2 mg/L (46.8-72.5, p = 0.074) at 400 mg twice daily. One patient experienced a grade 3 event (i.e., diarrhea). CONCLUSIONS: This study demonstrates that splitting intake moments of pazopanib leads to a 79% increase in Cmin, with acceptable tolerability. Therefore, this new dosing schedule offers a cost-neutral opportunity to optimize treatment in patients with low exposure. CLINICAL TRIAL REGISTRATION: NL6137 ( http://www.trialregister.nl ).

Quantitative Assessment of Elagolix Enzyme-Transporter Interplay and Drug-Drug Interactions Using Physiologically Based Pharmacokinetic Modeling.

INTRODUCTION: Elagolix is approved for the management of moderate-to-severe pain associated with endometriosis. The aim of this analysis was to develop a physiologically based pharmacokinetic (PBPK) model that describes the enzyme-transporter interplay involved in the disposition of elagolix and to predict the magnitude of drug-drug interaction (DDI) potential of elagolix as an inhibitor of P-glycoprotein (P-gp) and inducer of cytochrome P450 (CYP) 3A4. METHODS: A PBPK model (SimCYP® version 15.0.86.0) was developed using elagolix data from in vitro, clinical PK and DDI studies. Data from DDI studies were used to quantify contributions of the uptake transporter organic anion transporting polypeptide (OATP) 1B1 and CYP3A4 in the disposition of elagolix, and to quantitatively assess the perpetrator potential of elagolix as a CYP3A4 inducer and P-gp inhibitor. RESULTS: After accounting for the interplay between elagolix metabolism by CYP3A4 and uptake by OATP1B1, the model-predicted PK parameters of elagolix along with the DDI AUC∞ and Cmax ratios, were within 1.5-fold of the observed data. Based on model simulations, elagolix 200 mg administered twice daily is a moderate inducer of CYP3A4 (approximately 56% reduction in midazolam AUC∞). Simulations of elagolix 150 mg administered once daily with digoxin predicted an increase in digoxin Cmax and AUC∞ by 68% and 19%, respectively. CONCLUSIONS: A PBPK model of elagolix was developed, verified, and applied to characterize the disposition interplay between CYP3A4 and OATP1B1, and to predict the DDI potential of elagolix as a perpetrator under dosing conditions that were not tested clinically. PBPK model-based predictions were used to support labeling language for DDI recommendations of elagolix.

In vivo assessment of neuroinflammation in progressive multiple sclerosis: a proof of concept study with [18F]DPA714 PET.

BACKGROUND: Over the past decades, positron emission tomography (PET) imaging has become an increasingly useful research modality in the field of multiple sclerosis (MS) research, as PET can visualise molecular processes, such as neuroinflammation, in vivo. The second generation PET radioligand [18F]DPA714 binds with high affinity to the 18-kDa translocator-protein (TSPO), which is mainly expressed on activated microglia. The aim of this proof of concept study was to evaluate this in vivo marker of neuroinflammation in primary and secondary progressive MS. METHODS: All subjects were genotyped for the rs6971 polymorphism within the TSPO gene, and low-affinity binders were excluded from participation in this study. Eight patients with progressive MS and seven age and genetic binding status matched healthy controls underwent a 60 min dynamic PET scan using [18F]DPA714, including both continuous on-line and manual arterial blood sampling to obtain metabolite-corrected arterial plasma input functions. RESULTS: The optimal model for quantification of [18F]DPA714 kinetics was a reversible two-tissue compartment model with additional blood volume parameter. For genetic high-affinity binders, a clear increase in binding potential was observed in patients with MS compared with age-matched controls. For both high and medium affinity binders, a further increase in binding potential was observed in T2 white matter lesions compared with non-lesional white matter. Volume of distribution, however, did not differentiate patients from healthy controls, as the large non-displaceable compartment of [18F]DPA714 masks its relatively small specific signal. CONCLUSION: The TSPO radioligand [18F]DPA714 can reliably identify increased focal and diffuse neuroinflammation in progressive MS when using plasma input-derived binding potential, but observed differences were predominantly visible in high-affinity binders.

Brain Targeted Intranasal Zaleplon Nano-emulsion: In-Vitro Characterization and Assessment of Gamma Aminobutyric Acid Levels in Rabbits' Brain and Plasma at Low and High Doses.

BACKGROUND: Zaleplon is a pyrazolopyrimidin derivative hypnotic drug indicated for the short-term management of insomnia. Zaleplon belongs to Class II drugs, according to the biopharmaceutical classification system (BCS), showing poor solubility and high permeability. It undergoes extensive first-pass hepatic metabolism after oral absorption, with only 30% of Zaleplon being systemically available. It is available in tablet form which is unable to overcome the previous problems. OBJECTIVE: The aim of this study is to enhance solubility and bioavailability via utilizing nanotechnology in the formulation of intranasal Zaleplon nano-emulsion (ZP-NE) to bypass the barriers and deliver an effective therapy to the brain. METHOD: Screening studies were carried out wherein the solubility of zaleplon in various oils, surfactants( S) and co-surfactants(CoS) were estimated. Pseudo-ternary phase diagrams were constructed and various nano-emulsion formulations were prepared. These formulations were subjected to thermodynamic stability, in-vitro characterization, histopathological studies and assessment of the gamma aminobutyric acid (GABA) level in plasma and brain in rabbits compared to the market product (Sleep aid®). RESULTS: Stable NEs were successfully developed with a particle size range of 44.6±3.4 to 136.9±1.6 nm. CONCLUSION: A NE composed of 10% Miglyol® 812, 40% Cremophor® RH40 40%Transcutol® HP and 10% water successfully enhanced the bioavailability and brain targeting in the rabbits, showing a three to four folds increase than the marketed product.

Pharmacokinetic and Pharmacodynamic Analyses To Determine the Optimal Fixed Dosing Regimen of Iclaprim for Treatment of Patients with Serious Infections Caused by Gram-Positive Pathogens.

Iclaprim is a bacterial dihydrofolate reductase inhibitor that is currently being evaluated in two phase 3 trials for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI). Prior animal infection model studies suggest that the pharmacokinetic/pharmacodynamic (PK/PD) drivers for efficacy are area under the concentration-time curve from 0 to 24 h at steady state (AUC0-24ss), AUC/MIC, and time above the MIC during the dosing interval (T > MIC), while QTc prolongation was associated with the maximal concentration at steady state (Cmaxss) in a thorough QTc phase 1 study. Using PK data collected from 470 patients from the previously conducted phase 3 complicated skin and skin structure infection (cSSSI) trials, population PK modeling and Monte Carlo simulation (MCS) were used to identify a fixed iclaprim dosage regimen for the ongoing phase 3 ABSSSI studies that maximizes AUC0-24ss, AUC/MIC, and T > MIC while minimizing the probability of a Cmaxss of ≥800 ng/ml relative to the values for the previously employed cSSSI regimen of 0.8 mg/kg of body weight infused intravenously over 0.5 h every 12 h. The MCS analyses indicated that administration of 80 mg as a 2-h infusion every 12 h provides 28%, 28%, and 32% increases in AUC0-24ss, AUC/MIC, and T > MIC, respectively, compared to values for the 0.8-mg/kg cSSSI regimen, while decreasing the probability of a Cmaxss of ≥800 ng/ml, by 9%. Based on PK/PD analyses, 80 mg iclaprim administered over 2 h every 12 h was selected as the dosing scheme for subsequent phase 3 clinical trials.

Population Pharmacokinetics and Exposure Response Assessment of CC-292, a Potent BTK Inhibitor, in Patients With Chronic Lymphocytic Leukemia.

CC-292, a potent Bruton tyrosine kinase inhibitor, is under development for the treatment of B-cell malignancies. An analysis was performed to develop a population pharmacokinetic model of CC-292 and assess the influence of demographics and disease-related covariates on CC-292 exposure and to assess the exposure-response (overall response rate) relationship in patients with chronic lymphocytic leukemia. Population pharmacokinetic analysis was based on a 2-compartment base model conducted in NONMEM. Categorical exposure-response analysis was performed using logistic regression in SAS. The population pharmacokinetic analysis results indicated that CC-292 pharmacokinetic disposition is similar between healthy subjects and patients. CC-292 showed a larger central compartment volume of distribution than the peripheral compartment volume of distribution (158 L and 72 L, respectively) and a faster clearance than intercompartmental clearance (134 L/h and 18.7 L/h, respectively), indicating that for CC-292, clearance from blood occurs faster than distribution into deep tissues and organs. CC-292 clearance is not affected by demographics or baseline clinical lab factors, except for sex. Although sex significantly reduced variation of apparent clearance, the sex effect on apparent clearance is unlikely to be clinically relevant. The exposure-response analysis suggested that higher drug exposure is linearly correlated with higher overall response rate. A twice-daily dose regimen showed higher overall response rate as compared to once-daily dosing, consistent with a threshold concentration of approximately 300 ng/mL, above which the probability of overall response rate significantly increases.

Assessment of drug-drug interaction potential between ceritinib and proton pump inhibitors in healthy subjects and in patients with ALK-positive non-small cell lung cancer.

PURPOSE: The impact of proton pump inhibitors (PPIs) on the pharmacokinetics (PK) and efficacy of ceritinib was evaluated. METHODS: A healthy subject drug-drug interaction (DDI) study was conducted to assess the effect of esomeprazole on the PK of a single 750 mg dose of ceritinib. To further investigate the impact of PPIs on the PK and efficacy of ceritinib in ALK-positive cancer patients, two subgroup analyses were performed. Analysis 1 evaluated ceritinib steady-state trough concentration (Ctrough,ss) and overall response rate (ORR) by concomitant use of PPIs in patients from the ASCEND-1, -2, and -3 studies; analysis 2 evaluated ceritinib single-dose and steady-state AUC0-24h and C max by concomitant PPI use in patients from ASCEND-1 using a definition of PPI usage similar to that used in the healthy subject study. RESULTS: In the healthy subject study, co-administration of a single 750 mg dose of ceritinib with esomeprazole 40 mg for 6 days decreased ceritinib AUC0-∞ by 76% and C max by 79%. However, based on subgroup analysis 1, patients had similar C trough,ss and ORR regardless of concomitant PPI usage. Based on analysis 2, co-administration of a single 750 mg ceritinib dose with PPIs for 6 days in patients suggested less effect on ceritinib exposure than that observed in healthy subjects as AUC0-24h decreased by 30% and C max decreased by 25%. No clinically meaningful effect on steady-state exposure was observed after daily dosing. CONCLUSIONS: Long-term administration of ceritinib with PPIs does not adversely affect the PK and efficacy of ceritinib in ALK-positive cancer patients.

[Choosing wisely when prescribing statins]. / Verstandig kiezen bij het voorschrijven van statinen.

The Dutch campaign 'Verstandig kiezen', based on the American programme 'Choosing wisely', aims to improve quality in healthcare, with attention to cost control. The 'Choosing wisely'-based programme can be applied in the choice of a statin. Atorvastatin and rosuvastatin are regarded as equal choices in various guidelines regarding cardiovascular risk management. Generic atorvastatin is available, and is approximately 25 times cheaper than rosuvastatin in almost equipotent doses. Rosuvastatin provides a greater LDL reduction than atorvastatin. Patient LDL targets can usually be achieved with atorvastatin, and rosuvastatin is not needed. At group level, there are no relevant differences in adverse-events profile between both statins. Atorvastatin and rosuvastatin do have different pharmacokinetic interactions. When changing medication, good provision of information is a prerequisite for patient satisfaction and compliance. We advise use of atorvastatin instead of rosuvastatin as drug of choice when the LDL target is not reached using simvastatin. However, under specific conditions, rosuvastatin should be the treatment of choice. Efficacy and adverse effects should then be evaluated at individual patient level.

A fixed-dose combination tablet of gemigliptin and metformin sustained release has comparable pharmacodynamic, pharmacokinetic, and tolerability profiles to separate tablets in healthy subjects.

BACKGROUND: In type 2 diabetes mellitus, fixed-dose combination (FDC) can provide the complementary benefits of correction of multiple pathophysiologic defects such as dysfunctions in glycemic or metabolic control while improving compliance compared with separate tablets taken together. The objective of the study reported here was to compare the pharmacodynamic (PD), pharmacokinetic (PK), and tolerability profiles of gemigliptin and extended-release metformin (metformin XR) between FDC and separate tablets. METHODS: A randomized, open-label, single-dose, two-way, two-period, crossover study was conducted in 28 healthy male volunteers. Two FDC tablets of gemigliptin/metformin 25/500 mg or separate tablets of gemigliptin (50 mg ×1) and metformin XR (500 mg ×2) were orally administered in each period. Serial blood samples were collected up to 48 hours post-dose to determine dipeptidyl peptidase 4 (DPP-4) activity using spectrophotometric assay and concentrations of gemigliptin and metformin using tandem mass spectrometry. Geometric mean ratios (GMRs) of FDC to separate tablet formulations and their 90% confidence intervals (CIs) were calculated to compare the PD and PK parameters between the two formulations. Tolerability was assessed throughout the study. RESULTS: The plasma DPP-4 activity-time curves of the FDC and the separate tablets almost overlapped, leading to a GMR (90% CI) of the FDC to separate tablets for the plasma DPP-4 activity and its maximum inhibition of 1.00 (0.97-1.04) and 0.92 (0.82-1.05), respectively. Likewise, all of the GMRs (90% CIs) of FDC to separate tablets for the area under the plasma concentration-time curve and maximum plasma concentration of gemigliptin and metformin fell entirely within the conventional bioequivalence range of 0.80-1.25. Both the FDC and separate tablets were well tolerated. CONCLUSION: The PD, PK, and tolerability profiles of gemigliptin and metformin XR in FDC and separate tablets were found to be comparable. The FDC tablet of gemigliptin and metformin sustained release can be a convenient therapeutic option in patients with type 2 diabetes mellitus requiring a combination approach.

Metabolites in safety testing assessment in early clinical development: a case study with a glucokinase activator.

The present article summarizes Metabolites in Safety Testing (MIST) studies on a glucokinase activator, N,N-dimethyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide (PF-04937319), which is under development for the treatment of type 2 diametes mellitus. Metabolic profiling in rat, dog, and human hepatocytes revealed that PF-04937319 is metabolized via oxidative (major) and hydrolytic pathways (minor). N-Demethylation to metabolite M1 [N-methyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide] was the major metabolic fate of PF-04937319 in human (but not rat or dog) hepatocytes, and was catalyzed by CYP3A and CYP2C isoforms. Qualitative examination of circulating metabolites in humans at the 100- and 300-mg doses from a 14-day multiple dose study revealed unchanged parent drug and M1 as principal components. Because M1 accounted for 65% of the drug-related material at steady state, an authentic standard was synthesized and used for comparison of steady-state exposures in humans and the 3-month safety studies in rats and dogs at the no-observed-adverse-effect level. Although circulating levels of M1 were very low in beagle dogs and female rats, adequate coverage was obtained in terms of total maximal plasma concentration (∼7.7× and 1.8×) and area under the plasma concentration-time curve (AUC; 3.6× and 0.8× AUC) relative to the 100- and 300-mg doses, respectively, in male rats. Examination of primary pharmacology revealed M1 was less potent as a glucokinase activator than the parent drug (compound PF-04937319: EC50 = 0.17 µM; M1: EC50 = 4.69 µM). Furthermore, M1 did not inhibit major human P450 enzymes (IC50 > 30 µM), and was negative in the Salmonella Ames assay, with minimal off-target pharmacology, based on CEREP broad ligand profiling. Insights gained from this analysis should lead to a more efficient and focused development plan for fulfilling MIST requirements with PF-04937319.

Dopamine D2 receptor occupancy as a predictor of catalepsy in rats: a pharmacokinetic-pharmacodynamic modeling approach.

OBJECTIVES: Dopamine D2 receptor occupancy (D2RO) is the major determinant of efficacy and safety in schizophrenia drug therapy. Excessive D2RO (>80%) is known to cause catalepsy (CAT) in rats and extrapyramidal side effects (EPS) in human. The objective of this study was to use pharmacokinetic and pharmacodynamic modeling tools to relate CAT with D2RO in rats and to compare that with the relationship between D2RO and EPS in humans. METHODS: Severity of CAT was assessed in rats at hourly intervals over a period of 8 h after antipsychotic drug treatment. An indirect response model with and without Markov elements was used to explain the relationship of D2RO and CAT. RESULTS: Both models explained the CAT data well for olanzapine, paliperidone and risperidone. However, only the model with the Markov elements predicted the CAT severity well for clozapine and haloperidol. The relationship between CAT scores in rat and EPS scores in humans was implemented in a quantitative manner. Risk of EPS not exceeding 10% over placebo correlates with less than 86% D2RO and less than 30% probability of CAT events in rats. CONCLUSION: A quantitative relationship between rat CAT and human EPS was elucidated and may be used in drug discovery to predict the risk of EPS in humans from D2RO and CAT scores measured in rats.

Distribution of the phosphatidylinositol 3-kinase inhibitors Pictilisib (GDC-0941) and GNE-317 in U87 and GS2 intracranial glioblastoma models-assessment by matrix-assisted laser desorption ionization imaging.

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, and the limited available treatment options have not meaningfully impacted patient survival in the past decades. Such poor outcomes can be at least partly attributed to the inability of most drugs tested to cross the blood-brain barrier and reach all areas of the glioma. The objectives of these studies were to visualize and compare by matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry the brain and tumor distribution of the phosphatidylinositol 3-kinase (PI3K) inhibitors pictilisib (GDC-0941, 2-(1H-indazol-4-yl)-6-(4-methanesulfonyl-piperazin-1-ylmethyl)-4-morpholin-4-yl-thieno[3,2-d]pyrimidine) and GNE-317 [5-(6-(3-methoxyoxetan-3-yl)-7-methyl-4-morpholinothieno[3,2-d]pyrimidin-2-yl)pyrimidin-2-amine] in U87 and GS2 orthotopic models of GBM, models that exhibit differing blood-brain barrier characteristics. Following administration to tumor-bearing mice, pictilisib was readily detected within tumors of the contrast-enhancing U87 model whereas it was not located in tumors of the nonenhancing GS2 model. In both GBM models, pictilisib was not detected in the healthy brain. In contrast, GNE-317 was uniformly distributed throughout the brain in the U87 and GS2 models. MALDI imaging revealed also that the pictilisib signal varied regionally by up to 6-fold within the U87 tumors whereas GNE-317 intratumor levels were more homogeneous. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analyses of the nontumored half of the brain showed pictilisib had brain-to-plasma ratios lower than 0.03 whereas they were greater than 1 for GNE-317, in agreement with their brain penetration properties. These results in orthotopic models representing either the contrast-enhancing or invasive areas of GBM clearly demonstrate the need for whole-brain distribution to potentially achieve long-term efficacy in GBM.