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Ibrutinib, an antineoplastic agent tackling chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's Macroglobulinemia, falls under the category of BCS class II drugs, characterized by a puzzling combination of low solubility and high permeability. Its oral bioavailability remains a perplexing challenge, merely reaching 2.9 % due to formidable first-pass metabolism hurdles. In a bid to surmount this obstacle, researchers embarked on a journey to develop ibrutinib-loaded NLCs (Nanostructured Lipid Carriers) using a methodology steeped in complexity: a Design of Experiments (DoE)-based hot melted ultrasonication approach. Despite a plethora of methods for analyzing ibrutinib in various matrices, the absence of a spectrofluorimetric method for assessing it in rat plasma added to the enigma. Thus emerged a spectrofluorimetric method, embodying principles of white analytical chemistry and analytical quality by design, employing a Placket-Burman design for initial method exploration and a central composite design for subsequent refinement. This method underwent rigorous validation in accordance with ICH guidelines, paving the way for its application in scrutinizing the in-vivo pharmacokinetics of ibrutinib-loaded NLCs, juxtaposed against commercially available formulations. Surprisingly, the optimized NLCs exhibited a striking 1.82-fold boost in oral bioavailability, shedding light on their potential efficacy. The environmental impact of this method was scrutinized using analytical greenness tools, affirming its eco-friendly attributes. In essence, the culmination of these efforts has not only propelled advancements in drug bioavailability but also heralded the dawn of a streamlined and environmentally conscious analytical paradigm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chirality in 1,4-Dihydropyrimidines influences their pharmacological properties and synthetic strategies. Enantiomers of chiral drugs often exhibit different pharmacokinetic profiles. Therefore, separating and studying individual enantiomers is crucial to optimize drug efficacy and safety. Enantiomeric separation of ±4-(4-chlorophenyl)-6-methyl-2-oxo-N-(O-toyl)-1,2,3,4-tetrahydropyrimidine-5-carboxamide (DP-1), which is a 1,4-Dihydropyrimidine derivative is achieved on CHIRALCEL® OD-H column (particle size: 5 μm, inner diameter: 4.6 mm, length:150 mm), following by investigating the kinetic properties of (R) and (S) enantiomers. The separation was achieved with a mobile phase composed of 70% (v/v) isopropyl alcohol and 30% (v/v) n-hexane. For the bioanalytical study, acetonitrile was used to precipitate the rat plasma samples and validated the method according to USFDA guidelines. The validated bioanalytical method was then successfully applied to determine the pharmacokinetic parameters of the drug in biological samples. Molecular modeling techniques, specifically docking simulations, were employed to predict the elution order of DP-1 enantiomers. The docking results revealed moderate binding interactions between the enantiomers and the chiral stationary phase (CSP), which aligns with the theoretical expectation that stronger interactions lead to longer retention times on the column., (© 2024 Wiley Periodicals LLC.)

Background: Ibrutinib and zanubrutinib are Bruton tyrosine kinase inhibitors used to treat mantle cell lymphoma, chronic lymphocytic leukemia, and small lymphocytic lymphoma. Dihydroxydiol ibrutinib (DHI) is an active metabolite of the drug. A liquid chromatography-tandem mass spectrometry method was developed to detect ibrutinib, DHI, and zanubrutinib in human plasma., Methods: The method involved a protein precipitation step, followed by chromatographic separation using a gradient of 10 mM ammonium acetate (containing 0.1% formic acid)-acetonitrile. Ibrutinib-d5 was used as an internal standard. Analytes were separated within 6.5 minutes. The optimized multiple reaction monitoring transitions of m/z 441.1 → 304.2, 475.2 → 304.2, 472.2 → 455.2, and 446.2 → 309.2 were selected to inspect ibrutinib, DHI, zanubrutinib, and the internal standards in positive ion mode., Results: The validated curve ranges included 0.200-800, 0.500-500, and 1.00-1000 ng/mL for ibrutinib, DHI, and zanubrutinib, respectively. The precisions of the lower limit of quantification of samples were below 15.5%, the precisions of the other level samples were below 11.4%, and the accuracies were between -8.6% and 8.4%. The matrix effect and extraction recovery of all compounds ranged between 97.6%-109.0% and 93.9%-105.2%, respectively. The selectivity, accuracy, precision, matrix effect, and extraction recovery results were acceptable according to international method validation guidelines., Conclusions: A simple and rapid method was developed and validated in this study. This method was used to analyze plasma concentrations of ibrutinib and zanubrutinib in patients with mantle cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, or diffuse large B-cell lymphoma. The selected patients were aged between 44 and 74 years., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Endometriosis, a common and distressing gynecological condition, affects fertility and causes pain, is often managed with medications such as Elagolix. The present study aimed to construct a physiologically based pharmacokinetic (PBPK) model for elagolix to predict its pharmacokinetics in different populations, including those with special conditions, to enhance treatment strategies for endometriosis., Methods: The PBPK model was optimized using observational data based on the oral administration of elagolix in a healthy Chinese population under fasting conditions. Model accuracy was further verified by comparing the predicted postprandial elagolix concentration data for healthy Chinese individuals with observed data and by comparing these values with the predicted values in a US population model with renal injury or following multiple-dose administration., Results: Elagolix pharmacokinetic (PK) profiles in the Chinese and American populations exhibited no differences that were attributable to ethnicity. The model predicted in vivo PK in adolescents aged 14-18 years, revealing no clinically significant differences in the effects of elagolix between adolescents and adults. In addition, no predicted PK differences in individuals with overweight were observed. However, notable variations emerged in those classified as obesity class 2 and above compared to healthy individuals., Conclusion: Our study presents a novel PBPK model for elagolix in healthy Chinese women, addressing a clinical data gap for its use in adolescents and obese patients. By validating the model with real-world factors, including diet and renal impairment, we provide initial pharmacokinetic predictions for these populations, contributing to a more informed clinical approach., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: Accurate and selective LC/ESI-MSMS method development and validation for the quantitation of pacritinib is the primary goal of this study to perform kinetic studies in the healthy rabbit., Methods: Chromatographic resolution was accomplished with a hypersil/ODS (50 mm × 4.6 mm, 3 μ) analytical C 18 column and a mobile phase composition of 0.1% formic acid and ACN in the proportion of 25:75 with a 0.6 ml/min flow of the mobile phasic system from the analytical column. The method was employed by monitoring the established ionic transitions of m/z-473.25/98.09 for Pacritinib and 506.18/57.12 for the internal standard (Amprenavir) in multiple reaction monitoring., Results: The calibration plot regression line was y = 0.0002× + 0.007, with a correction coefficient (r 2 ) of 0.9989. The CV outcomes for the matrix effect at low-QC and high-QC levels were 4.79% and 4.91%, respectively. The percentage average recoveries for Pacritinib in High-QC (12.70 μg/ml), MQC (8.50 μg/ml), and Low-QC (1.19 μg/ml) were 95.87%, 103.64%, and 94.32%, respectively. The obtained values were found between 2.98 and 5.07% for the QC (1.19, 8.50, and 12.70 μg/ml) samples. The established procedure was subjected to kinetics study of Pacritinib after oral administration in rabbits. C max, T max, and T 1/2, of the Pacritinib tablets were 247.25 ± 3.32 ng/ml, 6.0 ± 0.03 h, and 12.24 ± 0.53 h, respectively. AUC 0-∞ infinity for Pacritinib tablets was 1691.74 ± 3.67 ng h/ml., Conclusion: After oral administration of Pacritinib to healthy rabbits, pharmacokinetic characteristics were presented, and the established technique was effectively verified., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

An open-label, single-center, phase I study was conducted to determine the absolute bioavailability and absorption, distribution, metabolism, and excretion of capivasertib-a potent, selective AKT serine/threonine kinase inhibitor-in healthy males. In part 1, six participants received a single oral dose of capivasertib (400 mg; tablets) followed by a [ 14 C]-radiolabeled intravenous microdose of capivasertib (100 μ g). After a 14-day washout, five of the participants proceeded to part 2 and received a single oral dose of [ 14 C]capivasertib (400 mg; solution). In part 1, median time of maximum observed concentration for capivasertib was 1.7 hours, geometric mean terminal elimination half-life was 12.9 hours, and absolute bioavailability was estimated at 28.6% (90% confidence interval, 23.9 to 34.2). In part 2, a high proportion of the administered radioactivity was recovered over the 168-hour sampling period [mean recovery: 95.1% (feces, 50.4%; urine, 44.7%)]. Unchanged capivasertib in urine accounted for 7.4% of the total dose and 21.1% of the systemically available drug. Geometric mean renal clearance was 8.3 L/h, suggesting active tubular secretion. Twelve metabolites were identified in plasma. M11 (AZ14102143)-the glucuronide conjugate of capivasertib, inactive as an AKT serine/threonine kinase inhibitor-was the most abundant, accounting for a mean 78.4% of the plasma drug-related area under the curve. Of 22 metabolites identified in excreta, M11 was the most abundant (mean 28.2% of administered dose), indicating direct glucuronidation as one of the major routes of metabolism. No new safety concerns were identified. SIGNIFICANCE STATEMENT: This study provides characterization of the pharmacokinetics of capivasertib-a potent, selective AKT serine/threonine kinase (AKT) inhibitor-including absolute bioavailability, mass balance, and metabolic fate in humans; the findings are being used to inform further clinical development. Absolute bioavailability was estimated at 28.6%, and mean recovery of the administered dose in excreta over 168 hours was 95.1%. M11 (AZ14102143)-the glucuronide conjugate, inactive as an AKT inhibitor-was the most abundant identified metabolite in plasma and excreta., (Copyright © 2024 by The Author(s).)

Abrocitinib is approved to treat moderate-to-severe atopic dermatitis and eliminated mainly through cytochrome P450 (CYP450) enzyme. Two commonly used antidepressants, amitriptyline and fluoxetine, could inhibit the activities of CYP2C19 and CYP3A4. In this study, we developed a new and quick ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for quantitatively analyzing the plasma concentration of abrocitinib, and further investigated the effects of amitriptyline or fluoxetine on the pharmacokinetics of abrocitinib in rats. The selectivity, linearity, recovery, accuracy, precision, matrix effect and stability of UPLC-MS/MS assay were satisfied according to the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines. Our result showed that when co-administered with amitriptyline and fluoxetine, the CLz/F of abrocitinib was reduced by 44.4 % and 33.3 %, respectively, while the AUC (0-t) of abrocitinib was increased by 77.7 % and 49.4 %, respectively. It indicated that amitriptyline and fluoxetine could significantly increase the plasma concentration of abrocitinib in rats. Thus, dose adjustment of abrocitinib may be required when it is combined with amitriptyline or fluoxetine in ongoing clinical practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Hematologic malignancies such as leukemia and lymphoma present treatment challenges due to their genetic and molecular heterogeneity. Ruxolitinib, a Janus kinase (JAK) inhibitor, has demonstrated efficacy in managing these cancers. However, optimal therapeutic outcomes are contingent upon maintaining drug levels within a therapeutic window, highlighting the necessity for precise drug monitoring., Methods: We developed a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify ruxolitinib in human plasma, improving upon traditional methods in specificity, sensitivity, and efficiency. The process involved the use of advanced chromatographic techniques and robust mass spectrometric conditions to ensure high accuracy and minimal matrix effects. The study was conducted using samples from 20 patients undergoing treatment, with calibration standards ranging from 10 to 2000 ng/mL., Results: The method displayed linearity ( R 2 > 0.99) across the studied range and proved highly selective with no significant interference observed. The method's precision and accuracy met FDA guidelines, with recovery rates consistently exceeding 85%. Clinical application demonstrated significant variability in ruxolitinib plasma levels among patients, reinforcing the need for individualized dosing schedules., Conclusion: The validated LC-MS/MS method offers a reliable and efficient tool for the therapeutic drug monitoring of ruxolitinib, facilitating personalized treatment approaches in hematologic malignancies. This approach promises to enhance patient outcomes by optimizing dosing to reduce toxicity and improve efficacy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Li, Zhang, Bai and Lu.)

Pemigatinib (PGT) is a recently FDA-approved small molecule kinase inhibitor used for the treatment of relapsed or refractory myeloid/lymphoid neoplasms in adults. This study introduces the development of a first microwell spectrofluorimetric method (MW-SFM) for quantifying PGT in FDA-approved tablets and plasma samples. The method utilized the enhancement of PGT's weak native fluorescence by blocking photoinduced electron transfer (PET) and micellization with sodium lauryl sulfate (SLS). The MW-SFM was performed in 96-microwell plates, and fluorescence signals were measured using a fluorescence microplate reader with excitation at 290 nm and emission at 350 nm. The method exhibited a linear range of 2-250 ng mL -1 , and a limit of quantitation was 6.5 ng mL -1 . The accuracy and precision of the method were confirmed with recovery rates ranging from 96.5% to 102.8% and relative standard deviations of 1.52% to 3.51%. The MW-SFM successfully analyzed Pemazyre® tablets, assessed content uniformity, and analyzed PGT-spiked human plasma samples. The greenness of the MW-SFM was verified using three different metric tools. In conclusion, the proposed MW-SFM is a valuable tool in supporting quality assessment of dosage forms, conducting pharmacokinetic studies, and monitoring therapeutic outcomes., (© 2024 John Wiley & Sons Ltd.)

The primary aim was to demonstrate bioequivalence between the 10/20 mg fixed-dose combination (FDC) of macitentan/tadalafil in a single tablet and the free combination of both drugs, and to evaluate the food effect on the 10/20 mg FDC in healthy participants. In this single-center, randomized, open-label, 3-way crossover, single-dose Phase 1 study in healthy adult participants, macitentan/tadalafil was administered as a 10/20 mg FDC formulation and compared with the free combination of macitentan and tadalafil. The food effect on the FDC was also evaluated. Pharmacokinetic sampling (216 h) was conducted. The 90% confidence intervals (CIs) for the geometric mean ratios of maximum observed plasma analyte concentration (C max ) and area under the plasma analyte concentration-time curves (AUCs) for Treatment A (FDC, fasted) versus C (free combination, fasted) were within bioequivalence limits demonstrating that the FDC formulation can be considered bioequivalent to the free combination. The 90% CIs for the geometric mean ratios of C max and AUC for Treatment B (FDC, fed) versus A (FDC, fasted) were contained within bioequivalence limits demonstrating that there was no food effect. The administration of the 10/20 mg FDC was generally safe and well tolerated in healthy participants. This study demonstrated bioequivalence between the FDC of macitentan/tadalafil (10/20 mg) in a single tablet and the free combination of both drugs in healthy participants, and that the FDC can be taken without regard to food, similarly to the individual components. The FDC was generally safe and well tolerated., (© 2024 Actelion Pharmaceuticals Ltd. Pharmacology Research & Perspectives published by British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics and John Wiley & Sons Ltd.)

Atopic dermatitis (AD) is a persistent, inflammatory skin condition that impacts approximately 15 to 20% of children and 1 to 3% of adults globally. Common skin manifestations include papules, papulovesicular, and brown or red patches with swelling, crusting, and flaking. Therefore, the drug abrocitinib (ABR) was approved by the US FDA as an oral treatment for atopic dermatitis. The present study outlines the development of innovative, thermostable, and pH-stable organic solvent-free nitrogen-doped carbon dots (N@CQDs) synthesized through a one-step method for evaluating ABR with a notable quantum yield of 33.84% to minimize the use of organic solvents. Their cost-effectiveness, eco-friendly characteristics, and outstanding photocatalytic properties have established them as a promising alternative to conventional luminescent techniques like fluorescent dyes and luminous derivatization technique. The reaction of ABR with N@CQDs led to a significant decrease in the luminescent response of the produced green and stable carbon quantum dots at 513 nm. The detection range was determined to be 1.0-150.0 ng mL -1 , with a lower limit of quantitation (LOQ) equal to 0.52 ng mL -1 based on the linear graph. The green method effectively used for analysis of ABR in pharmaceutical tablets and pharmacokinetic study with high sensitivity., (© 2024 John Wiley & Sons Ltd.)

Aim: The feasibility of using Tasso devices (Tasso-SST ® and Tasso + ) collecting capillary blood samples for measuring abrocitinib and its metabolites were evaluated, and assay concordance established between capillary and venous blood samplings. Methods: Capillary serum and venous plasma concentrations were measured using their respective qualified and validated assays. Concentration and exposure comparisons were conducted for abrocitinib and its metabolites (M1, M2 and M4) to establish assay concordance. Results: The correlation coefficient between capillary serum and venous plasma concentrations were >0.98 for all four analytes from three separate assays, and PK parameters (AUC last and C max ) were compared and met bioequivalence criteria. Conclusion: These results demonstrate the feasibility of patient-centric microsampling device, such as Tasso, in future abrocitinib pediatric study.

Background: Tirabrutinib is an orally effective, approved, and highly selective second-generation Bruton's tyrosine kinase (BTK) inhibitor for the treatment of recurrent or refractory primary central nervous system lymphoma (PCNSL)., Objective: This study aimed to develop an ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) method for the determination of tirabrutinib concentration in rat plasma, where zanubrutinib was used as an internal standard (IS). This method was also applied to study whether tirabrutinib would interact with voriconazole, itraconazole, and fluconazole in rats, providing a reference value for clinical medication guidance., Methods: In the current study, the organic solvent protein precipitation method was used to treat plasma samples, which is simple and reproducible. Tirabrutinib (m/z 455.32 → 320.21) and zanubrutinib ( m/z 472.13 → 455.04) were separated on a Waters Acquity BEH C18 column (2.1 × 50 mm, 1.7 μm) and detected by multiple reaction monitoring (MRM) in positive ionization mode., Results: The method showed good linearity in the range of 5-3000 ng/mL for tirabrutinib with the lower limit of quantification (LLOQ) of 5 ng/mL. The recovery and matrix effects were 85.7-91.0% and 102.0-113.3%, respectively. The accuracy, precision, stability, and carry-over effect were also acceptable. The method could also be used for determining the pharmacokinetic interaction of tirabrutinib in rats. The results showed AUC 0→∞ of tirabrutinib to be increased by 139.3% and 83.9% in the presence of voriconazole and fluconazole, respectively, while itraconazole had little effect., Conclusion: It is necessary to monitor the concentration of tirabrutinib in patients when it is combined with voriconazole and fluconazole to achieve a better therapeutic effect and reduce the risk of adverse reaction. Further research should be conducted in the future., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Tofacitinib is an oral JAK inhibitor for the treatment of rheumatoid arthritis (RA). The clinical efficacy and safety of an administered tofacitinib, either monotherapy or in combination with conventional synthetic disease-modifying anti-rheumatic drugs, mainly methotrexate (MTX), have been evaluated. The high plasma concentration with delayed medicine clearance may affect the liver and/or kidney functions. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC- MS/MS) method for the quantitative analysis of methotrexate, tofacitinib, and metabolite M9 in plasma of Sprague Dawley (SD) rats was developed, and its effectiveness was validated as well., Methods: Methotrexate, tofacitinib, M9 and fedratinib (internal standard, IS) were separated by gradient elution. The chromatography was performed on an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 μm) column with the mobile phases of acetonitrile and 0.1% formic acid aqueous solution with different proportions at the flow rate of 0.30 mL/min. In the positive ionization mode, the analyzes were detected using a Xevo TQ-S triple quadrupole tandem mass spectrometer, with the following mass transition pairs: m/z 313.12 → 148.97 for tofacitinib, m/z 329.10 → 165.00 for M9 and m/z 455.12 → 308.05 for methotrexate., Results: The obtained results manifested good calibration linearity over the ranges of tofacitinib at 0.1-100 ng/mL, M9 at 0.05-100 ng/mL, and methotrexate at 0.05-100 ng/mL. The lower limit of quantifications (LLOQs) of methotrexate, tofacitinib and M9 were 0.05 ng/mL, 0.1 ng/mL and 0.05 ng/mL, respectively. Intra-day and inter-day accuracy values were confirmed with a range of -6.3% to 12.7%, while intra-day and inter-- day precision values were ≤14.4%. Additionally, recoveries were greater than 86.5% for each compound without significant matrix effects., Conclusion: The currently established analytical method exhibited great potential for the evaluation of plasma concentrations of methotrexate, tofacitinib and M9 simultaneously, greatly reducing the detection time, which would serve as a supplementary role in formulating dose decisions to achieve personalized treatment, identify drugs that cause adverse reactions and finally, to assess drug-drug interactions on clinical studies., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Vericiguat, as a new stimulator of soluble guanylate cyclase (s- GC), was recently approved as a first-in-class treatment for reducing risks in patients with ejection fraction less than 45 percent and heart failure (HF) in the USA., Objective: The main aim of the present experiment was to establish an acceptable, sensitive assay based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for quantitatively analyzing the plasma concentration levels of vericiguat in rats, and to further evaluate the effect of apigenin on the metabolism of vericiguat in vivo ., Methods: In sample processes, acetonitrile was finally chosen for quickly precipitating protein. The levels of vericiguat in plasma were analyzed by a Xevo TQ-S triple quadrupole tandem mass spectrometry (Milford, MA, USA) in a positive ion mode., Results: The scope of the calibration standard for vericiguat ranged from 0.5 to 1000 ng/mL, where a great linearity was acceptable. The lower limit of quantification (also called LLOQ) of vericiguat presented the sensitivity of this assay was evaluated as low as 0.5 ng/mL. Additionally, selectivity, accuracy and precision, extraction recovery, matrix effect, and stability were all verified. Subsequently, this approach also supported to assess the plasmatic concentrations of vericiguat from an interaction survey on herb-- drug, in which oral administration of apigenin (20 mg/kg) obviously increased the plasmatic levels of vericiguat and altered the pharmacokinetics of vericiguat in rats., Conclusion: These results would help us to further understand the pharmacokinetic properties of vericiguat when co-administration with apigenin, and to avoid unexpected clinical risks in the future., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objective: To evaluate the reproducibility of cerebral adenosine A 2A receptor (A 2A R) quantification using [ 11 C]preladenant ([ 11 C]PLN) and PET in a test-retest study., Methods: Eight healthy male volunteers were enrolled. Dynamic 90 min PET scans were performed twice at the same time of the day to avoid the effect of diurnal variation. Subjects refrained from caffeine from 12 h prior to scanning, and serum caffeine was measured before radioligand injection. Arterial blood was sampled repeatedly during scanning and the fraction of the parent compound in plasma was determined. Total distribution volume (V T ) was estimated using 1- and 2-tissue compartment models (1-TCM and 2-TCM, respectively) and Logan graphical analysis (Logan plot) (t* = 30 min). Plasma-free fraction (f P ) of [ 11 C]PLN was measured and used for correction of V T values. Distribution volume ratio (DVR) was calculated from V T of target and reference regions and obtained by noninvasive Logan graphical reference tissue model (LGAR) (t* = 30 min). Absolute test-retest variability (aTRV), and intra-class correlation coefficient (ICC) of V T and DVR were calculated as indexes of repeatability. Correlation between DVR and serum concentration of caffeine (a nonselective A 2A R blocker) was analyzed by Pearson's correlation analysis., Results: Regional time-activity curves were well described by 2-TCM models. Estimation of V T by 2-TCM produced some erroneous values; therefore, the more robust Logan plot was selected as the appropriate model. Global mean aTRV was 20% for V T and 14% for V T /f P (ICC, 0.72 for V T and 0.87 for V T /f P ). Global mean aTRV of DVR was 13% for Logan plot and 10% for LGAR (ICC, 0.70 for Logan plot and 0.81 for LGAR). DVR estimates using LGAR and Logan plot were in good agreement (r 2  = 0.96). Coefficients of variation for V T , V T /f P , DVR (Logan plot), and DVR (LGAR) were 47%, 47%, 27%, and 18%, respectively. Despite low serum caffeine levels, significant concentration-dependent effects on [ 11 C]PLN binding to target regions were observed (p < 0.01)., Conclusions: In this study, moderate test-retest reproducibility and large inter-subject differences were observed with [ 11 C]PLN PET, possibly attributable to competition by baseline amount of caffeine. Analysis of plasma caffeine concentration is recommended during [ 11 C]PLN PET studies., Trial Registration: UMIN000030040., (© 2021. The Japanese Society of Nuclear Medicine.)

Purpose: Knowledge on Ruxolitinib exposure in patients with graft versus host disease (GvHD) is scarce. The purpose of this prospective study was to analyze Ruxolitinib concentrations of GvHD patients and to investigate effects of CYP3A4 and CYP2C9 inhibitors and other covariates as well as concentration-dependent effects., Methods: 262 blood samples of 29 patients with acute or chronic GvHD who were administered Ruxolitinib during clinical routine were analyzed. A population pharmacokinetic model obtained from myelofibrosis patients was adapted to our population and was used to identify relevant pharmacokinetic properties and covariates on drug exposure. Relationships between Ruxolitinib exposure and adverse events were assessed., Results: Median of individual mean trough serum concentrations was 39.9 ng/mL at 10 mg twice daily (IQR 27.1 ng/mL, range 5.6-99.8 ng/mL). Applying a population pharmacokinetic model revealed that concentrations in our cohort were significantly higher compared to myelofibrosis patients receiving the same daily dose (p < 0.001). Increased Ruxolitinib exposure was caused by a significant reduction in Ruxolitinib clearance by approximately 50%. Additional comedication with at least one strong CYP3A4 or CYP2C9 inhibitor led to a further reduction by 15% (p < 0.05). No other covariate affected pharmacokinetics significantly. Mean trough concentrations of patients requiring dose reduction related to adverse events were significantly elevated (p < 0.05)., Conclusion: Ruxolitinib exposure is increased in GvHD patients in comparison to myelofibrosis patients due to reduced clearance and comedication with CYP3A4 or CYP2C9 inhibitors. Elevated Ruxolitinib trough concentrations might be a surrogate for toxicity., (© 2021. The Author(s).)

Purpose: Pemigatinib (INCB054828), a potent and selective oral fibroblast growth factor receptor 1-3 inhibitor, is a Biopharmaceutical Classification System class II compound with good permeability and pH-dependent solubility that is predominantly metabolized by cytochrome P450 (CYP) 3A. Two drug-drug interaction studies, one with acid-reducing agents, esomeprazole (proton pump inhibitor [PPI]) and ranitidine (histamine-2 [H2] antagonist), and the other with potent CYP3A-modulating agents, itraconazole (CYP3A inhibitor) and rifampin (CYP3A inducer), were performed., Methods: Both were open-label, fixed-sequence studies conducted in up to 36 healthy participants each, enrolled into two cohorts (n = 18 each). Pemigatinib plasma concentration was measured, and pharmacokinetic parameters were derived by non-compartmental analysis., Results: There was an 88% and 17% increase in pemigatinib area under the plasma drug concentration-time curve (AUC) and maximum plasma drug concentration (C max ), respectively, with itraconazole, and an 85% and 62% decrease in pemigatinib AUC and C max with rifampin coadministration. There was a 35% and 8% decrease in pemigatinib AUC and C max , respectively, with esomeprazole, and a 2% decrease in C max and 3% increase in AUC with ranitidine coadministration. In both studies, all adverse events reported were grade ≤ 2., Conclusion: Coadministration with itraconazole or rifampin resulted in a clinically significant change in pemigatinib exposure. Therefore, coadministration of strong CYP3A inducers with pemigatinib should be avoided, and the dose of pemigatinib should be reduced if coadministration with strong CYP3A inhibitors cannot be avoided. The effect of PPIs/H2 antagonists on pemigatinib exposure was modest, and pemigatinib can be administered without regard to coadministration of PPIs/H2 antagonists., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background and Purpose: Pralsetinib is an FDA-approved oral small-molecule inhibitor for treatment of rearranged during transfection (RET) proto-oncogene fusion-positive non-small cell lung cancer. We investigated how the efflux transporters ABCB1 and ABCG2, the SLCO1A/1B uptake transporters and the drug-metabolizing enzyme CYP3A influence pralsetinib pharmacokinetics., Experimental Approach: In vitro, transepithelial pralsetinib transport was assessed. In vivo, pralsetinib (10 mg/kg) was administered orally to relevant genetically modified mouse models. Pralsetinib concentrations in cell medium, plasma samples and organ homogenates were measured using liquid chromatography-tandem mass spectrometry., Key Results: Pralsetinib was efficiently transported by human (h)ABCB1 and mouse (m)Abcg2, but not hACBG2. In vivo, mAbcb1a/1b markedly and mAbcg2 slightly limited pralsetinib brain penetration (6.3-and 1.8-fold, respectively). Testis distribution showed similar results. Abcb1a/1b;Abcg2 -/- mice showed 1.5-fold higher plasma exposure, 23-fold increased brain penetration, and 4-fold reduced recovery of pralsetinib in the small intestinal content. mSlco1a/1b deficiency did not affect pralsetinib oral availability or tissue exposure. Oral coadministration of the ABCB1/ABCG2 inhibitor elacridar boosted pralsetinib plasma exposure (1.3-fold) and brain penetration (19.6-fold) in wild-type mice. Additionally, pralsetinib was a modest substrate of mCYP3A, but not of hCYP3A4, which did not noticeably restrict the oral availability or tissue distribution of pralsetinib., Conclusions and Implications: SLCO1A/1B and CYP3A4 are unlikely to affect the pharmacokinetics of pralsetinib, but ABCG2 and especially ABCB1 markedly limit its brain and testis penetration, as well as oral availability. These effects are mostly reversed by oral coadministration of the ABCB1/ABCG2 inhibitor elacridar. These insights may be useful in the further clinical development of pralsetinib., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Aims: A chiral HPLC-MS/MS method for quantitation of an active metabolite (M2) of abrocitinib was validated in human plasma. Methods: Protein precipitation extraction and normal phase LC with baseline separation of five analytes (abrocitinib; isomeric metabolites M1, M2, M3 and M4) were achieved followed by mass spectrometric quantitation of M2 using positive-mode APCI. Results: With a 5-5000 ng/ml assay range using 100 μl K 2 EDTA aliquot, the assay provided short (17-min) runtime and robust separation up to approximately 330 injections on one column. Interday and intraday accuracy ranged from -6.80% to 13.4%; between-day and within-day precision was ≤10.4%. Conclusion: The method was used in multiple clinical studies, with excellent run passing rate and incurred sample reproducibility.

The COVID-19 pandemic has forced clinical studies to accommodate imposed limitations. In this study, the bioequivalence part could not be conducted as planned. Thus, the aim was to demonstrate bioequivalence, using an adaptive study design, of tadalafil in fixed-dose combination (FDC) tablets of macitentan/tadalafil with single macitentan and tadalafil (Canadian-sourced) tablets and assess the effect of food on FDC tablets in healthy subjects. This Phase 1, single-center, open-label, single-dose, two-part, two-period, randomized, crossover study enrolled 62 subjects. Tadalafil bioequivalence as part of FDC of macitentan/tadalafil (10/40 mg) with single-component tablets of macitentan (10 mg) and tadalafil (40 mg) was determined by pharmacokinetic (PK) assessment under fasted conditions. The effect of food on FDC was evaluated under fed and fasted conditions. Fasted 90% confidence intervals (CIs) for geometric mean ratios (GMRs) were within bioequivalence limits for tadalafil and macitentan. Fed and fasted 90% CIs for area under the curve (AUC) GMR were within bioequivalence limits. However, 90% CIs for maximum plasma concentration (C max ) GMR for macitentan and tadalafil were outside bioequivalence limits. One FDC-treated subject experienced a serious adverse event of transient ischemic attack (bioequivalence part). To address pandemic-imposed limitations, an adaptive study design was implemented to demonstrate that the FDC tablet was bioequivalent to the free combination of macitentan and tadalafil (Canadian-sourced). No clinically significant differences in PK were determined between fed and fasted conditions; the FDC formulation could be taken irrespective of meals. The FDC formulation under fasted and fed conditions was well tolerated with no clinically relevant differences in safety profiles between the treatment groups. NCT Number: NCT04235270., (© 2021 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

Background Brigatinib, a next-generation anaplastic lymphoma kinase (ALK) inhibitor, targets activated, mutant forms of ALK and overcomes mechanisms of resistance to the ALK inhibitors crizotinib, ceritinib, and alectinib. Brigatinib is approved in multiple countries for treatment of patients with ALK-positive non-small cell lung cancer. Based on population pharmacokinetic (PK) analyses, no dosage adjustment is required for patients with mild or moderate renal impairment. Methods An open-label, single-dose study was conducted to evaluate the PK of brigatinib (90 mg) in patients with severe renal impairment (estimated glomerular filtration rate < 30 mL/min/1.73 m 2 ; n = 8) and matched healthy volunteers with normal renal function (estimated glomerular filtration rate ≥ 90 mL/min/1.73 m 2 ; n = 8). Plasma and urine were collected for the determination of plasma protein binding and estimation of plasma and urine PK parameters. Results Plasma protein binding of brigatinib was similar between patients with severe renal impairment (92 % bound) and matched healthy volunteers with normal renal function (91 % bound). Unbound brigatinib exposure (area under the plasma concentration-time curve from time zero to infinity) was approximately 92 % higher in patients with severe renal impairment compared with healthy volunteers with normal renal function. The renal clearance of brigatinib in patients with severe renal impairment was approximately 20 % of that observed in volunteers with normal renal function. Conclusions These findings support a brigatinib dosage reduction of approximately 50 % in patients with severe renal impairment.Trial registry: Not applicable., (© 2021. The Author(s).)

Recent studies have shown that therapeutic drug monitoring of tyrosine kinase inhibitors (TKIs) could improve treatment efficacy and safety. A simple analytical method using high-performance LC/electrospray ionization-tandem mass spectrometry has been developed and validated for simultaneous quantification of BCR-ABL and Bruton's TKIs used for chronic leukemia (imatinib, dasatinib, bosutinib, nilotinib, and ibrutinib) in human plasma. Although these structures and physical properties are similar, owing to their different linear ranges, simultaneously determining the plasma levels of these five TKIs by applying optimal MS parameters remains difficult. A quantitative range exceeding 60,000-fold was required, and the linear dynamic ranges of imatinib, bosutinib, and nilotinib were limited because of the presence of a saturated detection signal. In this study, we applied the in-source collision-induced dissociation technique to control the ion amounts in mass spectrometry. This new method allowed rapid determination within 5 min with simple pretreatment. The method was validated according to the US Food and Drug Administration guidelines. Moreover, all samples of patients with chronic leukemia were successfully measured and their values were within the linear range of measurement. Therefore, our high-throughput analytical system is useful to measure the plasma concentrations of imatinib, dasatinib, bosutinib, nilotinib, and ibrutinib in clinical practice., (© 2021 John Wiley & Sons, Ltd.)

Renal (RIP) and hepatic (HIP) impairments are prevalent conditions in cancer patients. They can cause changes in gastric emptying time, albumin levels, hematocrit, glomerular filtration rate, hepatic functional volume, blood flow rates, and metabolic activity that can modify drug pharmacokinetics. Performing clinical studies in such populations has ethical and practical issues. Using predictive physiologically-based pharmacokinetic (PBPK) models in the evaluation of the PK of alectinib, ruxolitinib, and panobinostat exposures in the presence of cancer, RIP, and HIP can help in using optimal doses with lower toxicity in these populations. Verified PBPK models were customized under scrutiny to account for the pathophysiological changes induced in these diseases. The PBPK model-predicted plasma exposures in patients with different health conditions within average 2-fold error. The PBPK model predicted an area under the curve ratio (AUCR) of 1, and 1.8, for ruxolitinib and panobinostat, respectively, in the presence of severe RIP. On the other hand, the severe HIP was associated with AUCR of 1.4, 2.9, and 1.8 for alectinib, ruxolitinib, and panobinostat, respectively, in agreement with the observed AUCR. Moreover, the PBPK model predicted that alectinib therapeutic cerebrospinal fluid levels are achieved in patients with non-small cell lung cancer, moderate HIP, and severe HIP at 1-, 1.5-, and 1.8-fold that of healthy subjects. The customized PBPK models showed promising ethical alternatives for simulating clinical studies in patients with cancer, RIP, and HIP. More work is needed to quantify other pathophysiological changes induced by simultaneous affliction by cancer and RIP or HIP., (© 2021 John Wiley & Sons Ltd.)

Sotorasib is a KRAS inhibitor with promising anticancer activity in phase I clinical studies. This compound is currently under further clinical evaluation as monotherapy and combination therapy against solid tumors. In this study, a liquid chromatography-tandem mass spectrometric method to quantify sotorasib in mouse plasma and eight tissue-related matrices (brain, liver, spleen, kidney, small intestine, small intestine content, lung, and testis homogenates) was developed and validated. Protein precipitation using acetonitrile was utilized in 96-well format to extract sotorasib and erlotinib (internal standard) from mouse plasma and tissue homogenates. Separation of the analytes was performed on an Acquity UPLC® BEH C18 column by gradient elution of methanol and 0.1% formic acid in water at a flow rate of 0.6 ml/min. Sotorasib was detected by a triple quadrupole mass spectrometer with positive electrospray ionization in selected reaction monitoring mode. A linear calibration range of 2-2,000 ng/ml of sotorasib was achieved during the validation. Accuracy values were in the range of 90.7-111.4%, and precision values (intra- and interday) were between 1.7% and 9.2% for all tested levels in all investigated matrices. The method was successfully applied to investigate the plasma pharmacokinetics and tissue accumulation of sotorasib in female wild-type mice., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Pazopanib is widely used to treat renal cell carcinomas and soft tissue tumors in Japan. Pazopanib has significant therapeutic efficacy but it is associated with frequent severe adverse effects. Therapeutic drug monitoring (TDM) may help to prevent adverse effects. A more convenient and rapid pazopanib assay is desirable for the application of TDM in clinical settings. In this study, the authors developed a high-throughput method for quantifying pazopanib in human plasma using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS)., Methods: After a simple solid-phase extraction step using a 96-well plate, pazopanib was analyzed by UHPLC-MS/MS in the positive electrospray ionization mode., Results: The novel method fulfilled the requirements of the US Food and Drug Administration and the European Medicines Agency guidelines for assay validation, and the lower limit of quantification was 0.5 mcg/mL. The calibration curves were linear over the concentration range of 0.5-100 mcg/mL. The average recovery rate was 102.0% ± 3.9% (mean ± SD). The precision was below 5.0%, and the accuracy was within 12.0% for all quality control levels. Matrix effect varied between 90.9% and 97.1%. This assay was successfully applied to TDM of pazopanib trough concentrations in 3 patients treated with the drug for soft tissue tumors., Conclusions: The authors succeeded in developing a novel high-throughput UHPLC-MS/MS method for quantifying pazopanib in human plasma. This method can be applied to TDM of patients receiving pazopanib in clinical settings., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Firsocostat (FIR: previously GS-0976), a highly sensitive OATP substrate, reduces hepatic de novo lipogenesis (DNL) by inhibiting acetyl-CoA carboxylases (ACC). Measuring the pharmacodynamic (PD) efficacy of FIR on DNL provides a unique opportunity to determine optimal dosing strategies for liver-targeted OATP substrates in settings of altered OATP function. A randomized, four-way crossover drug-drug interaction study was conducted. Hepatic DNL, a marker for ACC activity, was measured in 28 healthy volunteers after reference, single dose FIR 10 mg, FIR 10 mg plus the OATP inhibitor rifampin (RIF) 300 mg i.v., or RIF 300 mg i.v. (control for DNL effect of RIF), each separated by a 7-day washout. Samples were collected for pharmacokinetic (PK) and PD assessments through 24 hours after each treatment. Hepatic DNL and its inhibition by FIR were assessed. Twenty-four subjects completed the study. All adverse events were mild. RIF alone increased hepatic DNL area under the effect curve from time of administration up to the time of the last quantifiable concentration (AUEC last ; 35.7%). Despite a 5.2-fold increase in FIR plasma exposure (area under the concentration-time curve from zero to infinity (AUC inf )) when administered with RIF, FIR alone, and FIR + RIF had the same hepatic PD effect, 37.1% and 34.9% reduction in DNL AUEC last , respectively, compared with their respective controls. These findings indicate that large decreases in OATP activity do not alter hepatic intracellular exposure (as inferred by no change in PD) for drugs that are primarily eliminated hepatically and permeability rate-limited, such as FIR. These results support PK theory that has been difficult to test and provide practical guidance on administration of liver-targeted drugs in settings of reduced OATP function., (© 2020 The Authors. Clinical Pharmacology & Therapeutics © 2020 American Society for Clinical Pharmacology and Therapeutics.)

AMG 510 is the first-in-class KRAS G12C inhibitor, currently in phase 2 clinical trials as an orphan drug to treat non-small cell lung cancer patients. We developed and validated a sensitive, selective, and high-throughput HPLC-MS/MS method for the quantitation of AMG 510 in mouse plasma per the regulatory guideline of the US Food and Drug and Administration. AMG 510 and the IS (MRTX-1257) were extracted from mouse plasma using tert-butyl methyl ether and chromatographed using an isocratic mobile phase (0.2% formic acid:acetonitrile; 25:75, v/v) at a flow rate of 0.65 mL/min on an Atlantis dC 18 column. AMG 510 and the IS eluted at ~0.95 and 0.73 min, respectively. AMG 510 and the IS were detected by positive electrospray ionization in multiple reaction monitoring using transition pair (Q1 → Q3) m/z 561.1 → 134.1 and m/z 566.5 → 98.2, respectively. Excellent linearity was achieved in the concentration range of 1.08-5040 ng/mL (r > 0.0996). No matrix effect and carryover were observed. Intra- and inter-day accuracies and precisions were within the acceptance range. AMG 510 was demonstrated to be stable under the tested storage conditions. This novel method has been applied to a pharmacokinetic study in mice., (© 2020 John Wiley & Sons, Ltd.)

Background: There continues to be a need for HIV prevention options that women can initiate and use autonomously. The dapivirine vaginal ring (VR) has been shown to have a favorable safety profile and reduce the risk of HIV-1 acquisition. We report on women's experiences with VR adherence during the MTN-025/HIV Open-label Prevention Extension (HOPE) study and responses to Residual Drug Level (RDL) results., Setting: Ten women at each of the 6 HOPE research sites in Lilongwe, Malawi; Durban (2 sites) and Johannesburg, South Africa; Kampala, Uganda; and Chitungwiza, Zimbabwe, were randomly selected (n = 60)., Methods: After confirmation of eligibility criteria, in-depth interviews were conducted where available RDL results were presented., Results: Many women with low RDL release measurements deflected blame onto other factors (the ring, the drug, and faulty testing machines) and distrust of the testing method. The disclosure of RDL results enabled some users to discuss their challenges experienced (fear of partner objections, perceived side effects, and removals during menses). Consistent users reported important motivators (support from others, protection from HIV, and enhanced sexual experiences from the VR)., Conclusion: The VR provided a sense of security for some women; however, adherence was still challenging for others regardless of it being a female controlled, long-acting HIV prevention technology. Adherence measurements may not be sustainable in the real-world implementation of the VR, although they can be seen as a benefit as they provide a better understanding of actual product use and provide women with a platform to discuss their experiences., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To characterize the safety, pharmacodynamics, and pharmacokinetics (PK) of vericiguat in healthy males., Methods: Six phase I studies were conducted in European, Chinese, and Japanese males. Subjects received oral vericiguat as a single dose (0.5-15.0 mg solution [for first-in-human study] or 1.25-10.0 mg immediate release [IR tablets]) or multiple doses (1.25-10.0 mg IR tablets once daily [QD] or 5.0 mg IR tablets twice daily for 7 consecutive days). Bioavailability and food effects on vericiguat PK (IR tablets) were also studied in European subjects., Results: Overall, 255 of 265 randomized subjects completed their respective studies. There were no deaths or serious adverse events. Vericiguat was generally well tolerated at doses ≤ 10.0 mg. In the first-in-human study, the most frequent drug-related adverse events were headache and postural dizziness (experienced by five subjects each [7.2%]). Three of four subjects who received vericiguat 15.0 mg (oral solution, fasted) experienced orthostatic reactions. Vericiguat (≤ 10.0 mg, IR tablets) was rapidly absorbed (median time to reach maximum plasma concentration ≤ 2.5 h [fasted]) with a mean half-life of about 22.0 h (range 17.9-27.0 h for single and multiple doses). No evidence for deviation from dose proportionality or unexpected accumulation was observed. Administration of vericiguat 5.0 mg IR tablets with food increased bioavailability by 19% (estimated ratio 119% [90% confidence interval]: 108; 131]), reduced PK variability, and prolonged vericiguat absorption relative to the fasted state., Conclusion: In general, vericiguat was well tolerated. These results supported further clinical evaluation of vericiguat QD in patients with heart failure., Registry Numbers: EudraCT: 2011-001627-21; EudraCT: 2012-000953-30.

Phosphatidylinositol 3-kinase (PI3K) inhibitors are a novel class of anticancer drugs that are approved to treat various malignancies. We report the development and validation of a HPLC method for the simultaneous quantitation of three PI3K inhibitors, namely copanlisib, duvelisib and idelalisib, in rat plasma as per the regulatory guidelines of the United States Food and Drug Administration. The method involves extraction of copanlisib, duvelisib and idelalisib along with an internal standard (IS; filgotinib) from rat plasma (100 μL) using a liquid-liquid extraction process. The chromatographic separation of the analytes was achieved using step-wise gradient elution on a Hypersil Gold C 18 column. The UV detection wavelength was set at λ max = 280 nm. Copanlisib, duvelisib, idelalisib and the IS eluted at 7.16, 12.6, 11.9 and 9.86 min, respectively, with a total run time of 15 min. The calibration curve ranged from 50 to 5000 ng/mL for all the analytes. Inter- and intra-day precision and accuracy, stability studies, dilution integrity and incurred sample reanalysis were investigated for all three analytes, and the results met the acceptance criteria. The validated HPLC method was successfully applied to a pharmacokinetic study in rats., (© 2020 John Wiley & Sons, Ltd.)

What Is Known and Objective: The purpose of this study was to investigate the relationships among nilotinib plasma trough concentration (C 0 ), low-density lipoprotein (LDL) cholesterol, and PCSK9 plasma concentration in 31 patients with chronic myeloid leukaemia., Methods: Plasma concentrations of nilotinib and PCSK9 were measured by high-performance liquid chromatography and enzyme-linked immunosorbent assays, respectively., Results and Discussion: LDL cholesterol concentrations at 1 month after nilotinib treatment were significantly increased compared with those before therapy. The mean C 0 (±SD) of nilotinib at 1, 2, and 3 months after nilotinib treatment were 645 ± 516, 902 ± 623, and 951 ± 1088 ng/mL, respectively. Mean PCSK9 concentrations at 3 months after nilotinib treatment were significantly higher than those at the start of therapy (320 vs 257 ng/mL, respectively, P = .019). When the change rate in the PCSK9 concentration induced by nilotinib was classified with a cut-off value of +40%, the change rate in LDL cholesterol in patients with a change rate in PCSK9 of ≥40% was significantly higher than that in patients with a PCSK9 change rate of <40% (67.1% vs 38.0%, P = .043); however, there were no differences in mean nilotinib C 0 ., What Is New and Conclusion: Nilotinib may lead to hypercholesterolaemia by increasing plasma concentrations of PCSK9 after indirect inhibition of mammalian target of rapamycin (mTOR) complex 1. In addition, certain patients seem to have high sensitivity for nilotinib in a signalling cascade of the PI3K/Akt/mTOR pathway, despite low plasma concentrations of nilotinib. Consequently, nilotinib-induced hypercholesterolaemia could not be predicted based on the plasma concentration of nilotinib., (© 2020 John Wiley & Sons Ltd.)

We aimed to use serum metabolomics to discriminate infants with severe respiratory syncytial virus (RSV) bronchiolitis who later developed subsequent recurrent wheezing from those who did not and to investigate the relationship between serum metabolome and host immune responses with regard to the subsequent development of recurrent wheezing. Fifty-one infants who were hospitalized during an initial episode of severe RSV bronchiolitis at 6 months of age or less were included and followed for up to the age of 3 years. Of them, 24 developed subsequent recurrent wheezing and 27 did not. Untargeted serum metabolomics was performed by ultraperformance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-MS/MS). Cytokines were measured by multiplex immunoassay. Difference in serum metabolomic profiles was observed between infants who developed recurrent wheezing and those who did not. L-lactic acid level was significantly higher in infants with recurrent wheezing than those without. Pyrimidine metabolism, glycerophospholipid metabolism, and arginine biosynthesis were identified as the most significant changed pathways between the two groups. Moreover, L-lactic acid level was positively associated with serum CXCL8 level. This exploratory study showed that differential serum metabolic signatures during severe RSV bronchiolitis in early infancy were associated with the development of subsequent recurrent wheezing in later childhood., (© 2020 APMIS. Published by John Wiley & Sons Ltd.)

An LC-tandem mass spectrometry method was developed and validated for the simultaneous quantitation of fimasartan and sacubitrilat using positive ion mode. The protein precipitation method was employed for the extraction of fimasartan, sacubitrilat and alprazolam (internal standard) from rat heparinized plasma. Baseline separation of the analytes was accomplished using an ACE-5, C 18 (4.6 × 50 mm) column and gradient elution of mobile phase A (5 mm ammonium formate and 0.1% formic acid in purified water) and B (acetonitrile:methanol, 80:20; v/v). All peaks of interest were eluted within a 5-min runtime. The quantitation was achieved in the selected reaction monitoring mode. The developed method was validated as per US Food and Drug Administration guidelines and met the pre-defined acceptance criteria. The method showed linearity from 5 to 10,000 ng/mL. The accuracy/precision of intra- and inter-batch assays was 96.64%/2.05% to 109.17%/13.70% and 100.74%/3.76% to 106.39%/9.75% for fimasartan and 100.02%/1.49% to 113.80%/9.38% and 100.75%/2.31% to 108.40%/7.74% for sacubitrilat, respectively, in rat plasma. Fimasartan and sacubitrilat remained stable in rat plasma at different experimental conditions up to 21 days. The developed method was sensitive, selective and applied successfully to monitor plasma concentrations of fimasartan and sacubitrilat in an oral rat pharmacokinetic study., (© 2020 John Wiley & Sons, Ltd.)

Purpose: Therapeutic drug monitoring (TDM) is widely used in clinical practice to maximize drug efficacy and minimize toxicities. Currently, it is also practiced in the use of oral molecular targeted drugs. The objective of this study was to assess the clinical importance of measuring the systemic concentration of oral molecular targeted drugs used to treat renal cell carcinoma (RCC)., Methods: The systemic concentrations of the oral molecular targeted drugs sorafenib, sunitinib, axitinib, pazopanib, and everolimus used for RCC were useful for therapeutic interventions, and clinical outcomes were evaluated retrospectively., Results: The interventional use of systemic drug concentration was confirmed in 26 of 87, and their categories are presented. The systemic concentration of sunitinib was useful in dose reduction and/or discontinuation (n = 10), dose escalation (n = 3), and adherence monitoring (n = 2). Nine of the 10 patients whose dose was reduced showed reduced adverse event. Two patients who were intervened in adherence monitor showed improved adherence. For axitinib, dose reduction and/or discontinuation (n = 1) and dose escalation (n = 6) were confirmed. For pazopanib, dose reduction and/or discontinuation (n = 1) and drug interaction detection (n = 1) were confirmed, both of them were confirmed to have reduced adverse events. For everolimus, dose reduction and/or discontinuation (n = 1) and drug interaction detection (n = 1) were confirmed, a patient with reduced dose recovered from adverse events. Interventions for sorafenib were not identified., Conclusions: This study demonstrated that systemic concentrations of oral molecular targeted drugs for RCC were considered to be clinically useful for dose adjustment, monitoring of treatment adherence, and the detection of drug interactions. Moreover, this information could be successfully used to guide individualized therapy to maximize the antitumor effects of these drugs.

Selection of a personalized dose for an individual patient can be informed by the patient's preferences, translated as weights on each of the clinically relevant safety and efficacy drug attributes, based on results from a brief patient preference elicitation questionnaire. In this analysis, the weighted attributes were simulated to represent various endometriosis patient profiles. Exposure-response simulations were performed for elagolix, a drug approved for management of moderate to severe pain associated with endometriosis, across a range of plasma exposures corresponding to a range of doses. The results were combined to calculate a personalized clinical utility index. An interactive user-friendly online application was developed and envisioned as a physician's desk tool to personalize the dose selection process based on individual patient preferences. This demonstration should serve as an example of how patient/physician conversation can be facilitated with quantitative tools for personalizing the dose., (© 2020 AbbVie Inc. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

Lemborexant is a novel dual orexin receptor antagonist recently approved for the treatment of insomnia in the United States and Japan. Here, disposition and metabolic profiles were investigated in healthy human subjects. After single oral administration of 10 mg [ 14 C]lemborexant (100 µCi), plasma concentrations of lemborexant and radioactivity peaked at 1 hour postdose and decreased biphasically. Cumulative recovery of the administered radioactivity within 480 hours was 86.5% of the dose, with 29.1% in urine and 57.4% in feces. Unchanged lemborexant was not detected in urine but accounted for 13.0% of the dose in feces, suggesting that the main elimination pathway of lemborexant was metabolism. Metabolite analyses revealed that the major metabolic pathways of lemborexant are oxidation of the dimethylpyrimidine moiety and subsequent further oxidation and/or glucuronidation. In plasma, lemborexant was the dominant component, accounting for 26.5% of total drug-related exposure. M4, M9, M10, and M18 were detected as the major radioactive components; M10 was the only metabolite exceeding 10% of total drug-related exposure. Although M4, M9, and M10 showed binding affinity for orexin receptors comparable to that of lemborexant, their contributions to the sleep-promoting effects of lemborexant are likely low because of the limited brain penetration by P-glycoprotein. Exposure comparison between humans and nonclinical toxicology species confirmed that plasma exposure of M10 was higher in at least one animal species compared with that in humans, indicating that there is no disproportionate metabolite in humans, as defined by International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use M3(R2) and U.S. Food and Drug Administration Metabolite in Safety Testing guidance; therefore, no additional toxicology studies are needed. SIGNIFICANCE STATEMENT: This study provides detailed data of the disposition and metabolism of lemborexant, a novel therapeutic drug for insomnia, in humans, as well as a characterization of the circulating metabolites and assessment of their contributions to efficacy and safety. The information presented herein furthers our understanding of the pharmacokinetic profiles of lemborexant and its metabolites and will promote the safe and effective use of lemborexant in the clinic., (Copyright © 2020 by The American Society for Pharmacology and Experimental Therapeutics.)

Aim and Objective: An analytical method for the determination of mobocertinib, an investigational tyrosine kinase inhibitor, was developed and optimized by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) in rat plasma., Materials and Methods: Plasma samples were pretreated by the protein precipitation method with a methanol solution of osimertinib as the internal standard (IS). Chromatographic separation was performed using an Inertsil ODS-3 column (50 mm × 4.6 mm, I.D. 5 μm) with the temperature maintained at 40°C. The mobile phase consisted of water (containing 0.1% formic acid) and methanol in a gradient mode at a flow rate of 0.5 mL/min. Mass spectrometric detection was carried out in the selected reaction monitoring (SRM) mode with positive electrospray ionization, and the mass transitions of mobocertinib and osimertinib were m/z 587.01 → 71.88 and m/z 499.80 → 71.94, respectively. The method was validated in terms of selectivity, linearity, accuracy and precision, extraction recovery and matrix effect, stability and carryover as per the guidelines for bioanalytical method validation (FDA, 2018). The method was applied to the pharmacokinetic study of mobocertinib in rats by oral gavage at the doses of 2, 6, and 18 mg/kg. A total of 216 plasma samples from 18 rats were analyzed., Results: The results showed good linearity over the range of 1-1000 ng/mL (R2 = 0.9957). The intra-batch accuracy was within 94.65-102.59% and the precision was within 5.49-10.46%. The inter-batch accuracy was within 97.08-102.25% with a precision of 7.54-10.13%. The extraction recovery and matrix factor were acceptable for the bioanalysis of mobocertinib. Additionally, mobocertinib was found to be stable under the detected conditions. Mobocertinib showed linear pharmacokinetic characteristics following oral administration to rats at 2.0-18.0 mg/kg., Conclusion: The developed and validated method was successfully employed in the pharmacokinetic study in rats following oral administration of mobocertinib at the doses of 2, 6, and 18 mg/kg., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Achondroplasia is caused by gain-of-function mutations in FGFR3 gene and leads to short-limb dwarfism. A stabilized analogue of C-type natriuretic peptide (CNP) is known to elongate bone by interacting with FGFR3 signals and thus is a promising drug candidate. However, it needs daily administration by percutaneous injection. FGFR inhibitor compounds are other drug candidates for achondroplasia because they directly fix the mutant protein malfunction. Although FGFR inhibitors elongate the bone of model mice, their adverse effects are not well studied. In this study, we found that a new FGFR inhibitor, ASP5878, which was originally developed as an anti-cancer drug, elongated the bone of achondroplasia model male mice at the dose of 300 μg/kg, which confers an AUC of 275 ng·h/ml in juvenile mice. Although ASP5878 was less effective in bone elongation than a CNP analogue, it is advantageous in that ASP5878 can be administered orally. The AUC at which minimal adverse effects were observed (very slight atrophy of the corneal epithelium) was 459 ng·h/ml in juvenile rats. The positive discrepancy between AUCs that brought efficacy and minimal adverse effect suggests the applicability of ASP5878 to achondroplasia in the clinical setting. We also analyzed effects of ASP5878 in a patient-specific induced pluripotent stem cell (iPSC) model for achondroplasia and found the effects on patient chondrocyte equivalents. Nevertheless, cautious consideration is needed when referring to safety data obtained from its application to adult patients with cancer in clinical tests.

Context: Naringenin and tofacitinib are often used together for treatment of rheumatoid arthritis in Chinese clinics. Objective: This experiment investigates the effect of naringenin on the pharmacokinetics of tofacitinib in rats. Materials and methods: Twelve Sprague-Dawley rats were randomly divided into two groups (experimental group and control group). The experimental group was pre-treated with naringenin (150 mg/kg/day) for two weeks before dosing tofacitinib, and equal amounts of CMC-Na solution in the control group. After a single oral administration of 5 mg/kg of tofacitinib, 50 μL blood samples were directly collected into 1.5 mL heparinized tubes via the caudal vein at 0.083, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 h. The plasma concentration of tofacitinib was quantified by UPLC/MS-MS. Results: Results indicated that naringenin could significantly affect the pharmacokinetics of tofacitinib. The AUC 0-24 of tofacitinib was increased from 1222.81 ± 222.07 to 2016.27 ± 481.62 ng/mL/h, and the difference was significant ( p  < 0.05). Compared with the control group, the T max was increased from 0.75 ± 0.29 to 3.00 ± 0.00 h ( p  < 0.05), and the MRT (0-24) was increased from 4.90 ± 0.51 to 6.57 ± 0.66 h ( p  < 0.05), but the clearance was obviously decreased from 4.10 ± 0.72 to 2.42 ± 0.70 L/h/kg ( p  < 0.05) in experimental group. Although the C max and t 1/2 of tofacitinib were increased, there were no significant differences ( p  > 0.05). Conclusions: This research demonstrated a drug-drug interaction between naringenin and tofacitinib possibly when preadministered with naringenin; thus, we should pay attention to this possibility in the clinic.

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. It is eliminated via multiple pathways including oxidative metabolism (∼70%) and renal excretion (29%). This study aimed to predict the impact of drug-drug interactions and renal or hepatic impairment on tofacitinib pharmacokinetics using a physiologically based pharmacokinetic (PBPK) model. The model was developed using Simcyp based on the physicochemical properties and in vitro and in vivo pharmacokinetics data for tofacitinib. The model was verified by comparing the predicted pharmacokinetic profiles with those observed in available clinical studies after single or multiple doses of tofacitinib, as well as with tofacitinib as a victim of drug-drug interactions (because of inhibition of cytochrome P450 [CYP450] 3A4, CYP450 2C19, or CYP450 induction). In general, good agreement was observed between Simcyp predictions and clinical data. The results from this study provide confidence in using the PBPK modeling and simulation approach to predict the pharmacokinetics of tofacitinib under intrinsic (eg, renal or hepatic impairment) or extrinsic (eg, inhibition of CYP450 enzymes and/or renal transporters) conditions. This approach may also be useful in predicting pharmacokinetics under untested or complex situations (eg, when a combination of intrinsic and extrinsic factors may impact pharmacokinetics) when conducting clinical studies may be difficult, in response to health authority questions regarding dosing in special populations, or for labeling discussions., (© 2020 Pfizer Inc. The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Lemborexant is a novel orexin receptor antagonist approved in the United States and Japan for the treatment of insomnia. This article describes the population pharmacokinetics (PK) of lemborexant and the relationship of its daily steady-state exposure (C av,ss ) to the probability of most frequent treatment-emergent adverse events (TEAEs). The 12 230-observation, 1892-subject PK data set included data from 12 clinical studies with predominantly female subjects (66%) ranging in age from 18 to 88 years and from 37 to 168 kg in body weight. The 1664-subject exposure-response data set included data from 3 late-stage studies. Lemborexant pharmacokinetics were described by a 3-compartment model with combined first- and zero-order absorption with lag time and linear elimination. Oral clearance decreased with increasing body mass index (exponent, -0.428), increasing alkaline phosphatase levels (exponent, -0.118), and was 26% lower in the elderly (≥65 years). Across the adverse event analysis, the frequency of subjects experiencing TEAEs during active treatment ranged from approximately 3% to 8%, in the range estimated for placebo. With and without adjustment for age, lemborexant exposure (C av,ss ) was not a clinically meaningful linear predictor of the probability of specific TEAEs: somnolence, nasopharyngitis, flu/influenza, urinary tract infection, upper respiratory tract infection, or headache. Given the small effect sizes of covariates of the PK model and a low degree of association of lemborexant TEAEs and exposure over the range of phase 3 (therapeutic) 5- and 10-mg doses, lemborexant can be safely administered without the need for dose adjustment., (© 2020 Eisai Inc. The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Larotrectinib is a first-generation tropomyosin kinase inhibitor, approved for the treatment of solid tumors. In this paper, we present a validated dried blood spot (DBS) method for the quantitation of larotrectinib from mouse blood using HPLC-MS/MS, which was operated under multiple reaction monitoring mode. To the DBS disc cards, acidified methanol enriched with internal standard (IS; enasidenib) was added and extracted using tert-butyl methyl ether as an extraction solvent with sonication. Chromatographic separation of larotrectinib and the IS was achieved on an Atlantis dC 18 column using 10 mm ammonium formate-acetonitrile (30:70, v/v) delivered at a flow-rate of 0.80 ml/min. Under these optimized conditions, the retention times of larotrectinib and the IS were ~0.93 and 1.37 min, respectively. The total run time was 2.50 min. Larotrectinib and the IS were analyzed using positive ion scan mode and parent-daughter mass to charge ion (m/z) transitions of 429.1 → 342.1 and 474.1 → 267.1, respectively, were used for the quantitation. The calibration range was 1.06-5,080 ng/ml. No matrix effect or carryover was observed. Hematocrit did not influence DBS larotrectinib concentrations. All of the validation parameters met the acceptance criteria. The applicability of the validated method was shown in a mouse pharmacokinetic study., (© 2020 John Wiley & Sons, Ltd.)

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., (© 2020 AbbVie Inc. The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Purpose: Brigatinib, a next-generation anaplastic lymphoma kinase (ALK) inhibitor, demonstrated superior progression-free survival (PFS) and improved health-related quality of life (QoL) versus crizotinib in advanced ALK inhibitor-naive ALK-positive non-small cell lung cancer (NSCLC) at first interim analysis (99 events; median brigatinib follow-up, 11.0 months) in the open-label, phase III ALTA-1L trial (ClinicalTrials.gov identifier: NCT02737501). We report results of the second prespecified interim analysis (150 events)., Methods: Patients with ALK inhibitor-naive advanced ALK-positive NSCLC were randomly assigned 1:1 to brigatinib 180 mg once daily (7-day lead-in at 90 mg once daily) or crizotinib 250 mg twice daily. The primary end point was PFS as assessed by blinded independent review committee (BIRC). Investigator-assessed efficacy, blood samples for pharmacokinetic assessments, and patient-reported outcomes were also collected., Results: Two hundred seventy-five patients were randomly assigned (brigatinib, n = 137; crizotinib, n = 138). With median follow-up of 24.9 months for brigatinib (150 PFS events), brigatinib showed consistent superiority in BIRC-assessed PFS versus crizotinib (hazard ratio [HR], 0.49 [95% CI, 0.35 to 0.68]; log-rank P < .0001; median, 24.0 v 11.0 months). Investigator-assessed PFS HR was 0.43 (95% CI, 0.31 to 0.61; median, 29.4 v 9.2 months). No new safety concerns emerged. Brigatinib delayed median time to worsening of global health status/QoL scores compared with crizotinib (HR, 0.70 [95% CI, 0.49 to 1.00]; log-rank P = .049). Brigatinib daily area under the plasma concentration-time curve was not a predictor of PFS (HR, 1.005 [95% CI, 0.98 to 1.031]; P = .69)., Conclusion: Brigatinib represents a once-daily ALK inhibitor with superior efficacy, tolerability, and QoL over crizotinib, making it a promising first-line treatment of ALK-positive NSCLC.

A rapid, simple, and highly sensitive electroanalytical method was developed for the first time for the detection of ultra-trace amounts of nilotinib in sodium lauryl sulphate media. The electrochemical behavior of nilotinib was investigated on a glassy carbon electrode in the absence and presence of sodium lauryl sulphate media by cyclic voltammetry and adsorptive stripping voltammetric methods. The cyclic voltammograms proved that the electrochemical behavior of nilotinib showed irreversible and diffusion-adsorption-controlled oxidation processes in 0.1 M H 2 SO 4 . The effect of surfactant concentration on the first and second peaks of nilotinib was examined. Depending on whether the surfactants had a monomer or monolayer hemimicelle structure, they were attracted to amine moieties at related points in the nilotinib structure through the electrostatic interaction. The sensitivity of the method was markedly enhanced in the presence of surfactants using adsorptive stripping square-wave voltammetry. Under optimum conditions, nilotinib was determined in a concentration range of 2.0 × 10 -8 to 2.0 × 10 -6  mol L -1 , with a limit of detection of 6.33 × 10 -9  mol L -1 in 0.1 M H 2 SO 4 containing 2.0 × 10 -7  mol L -1 sodium lauryl sulphate. The proposed method can be applied for the sensitive determination of nilotinib in biological samples. Graphical abstract.

Parsaclisib, a selective, potent phosphatidylinositol 3-kinase delta inhibitor being developed for the treatment of cancer and autoimmune diseases, is primarily metabolized by cytochrome P450 (CYP) 3A4. This study assessed the pharmacokinetics (PK) and safety of parsaclisib alone or combined with itraconazole (potent CYP3A inhibitor) or rifampin (potent CYP3A4 inducer) in healthy participants. In this open-label, fixed-sequence study, cohort 1 received oral parsaclisib 10 mg once daily on days 1 and 8 and oral itraconazole 200 mg once daily on days 4-11; cohort 2 received oral parsaclisib 20 mg once daily on days 1 and 11 and oral rifampin 600 mg once daily on days 4-12. Parsaclisib plasma concentration was tested and PK parameters calculated by noncompartmental analysis. Geometric mean ratios (GMRs) and 2-sided 90% confidence intervals (CIs) were estimated by 2-factor analysis of variance. Thirty-six healthy participants were enrolled (18 per cohort). Parsaclisib maximum plasma drug concentration (C max ) and area under the concentration-time curve extrapolated to infinity (AUC 0-∞ ) were increased by 21% and 107% with concomitant itraconazole versus parsaclisib alone (GMR, 1.21; 90%CI, 1.14-1.29; and 2.07; 90%CI, 1.97-2.17, respectively). Parsaclisib C max and AUC were reduced by 43% and 77%, respectively, with concomitant rifampin versus parsaclisib alone (GMR, 0.57; 90%CI, 0.53-0.60; and 0.23; 90%CI, 0.21-0.24, respectively). Headache was the most common adverse event, reported by 13.9% of participants (all in cohort 2). Single-dose parsaclisib alone or combined with itraconazole or rifampin appeared safe and well tolerated in healthy participants. Parsaclisib dose adjustment may be necessary with concomitant administration of strong CYP3A4 inhibitors or inducers., (© 2020 Incyte Corporation. The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Tepotinib (MSC2156119J) is an oral, potent, highly selective MET inhibitor. This open-label, phase I study in healthy volunteers (EudraCT 2013-003226-86) investigated its mass balance (part A) and absolute bioavailability (part B). In part A, six participants received tepotinib orally (498 mg spiked with 2.67 MBq [ 14 C]-tepotinib). Blood, plasma, urine, and feces were collected up to day 25 or until excretion of radioactivity was <1% of the administered dose. In part B, six participants received 500 mg tepotinib orally as a film-coated tablet, followed by an intravenous [ 14 C]-tepotinib tracer dose (53-54 kBq) 4 h later. Blood samples were collected until day 14. In part A, a median of 92.5% (range, 87.1-96.9%) of the [ 14 C]-tepotinib dose was recovered in excreta. Radioactivity was mainly excreted via feces (median, 78.7%; range, 69.4-82.5%). Urinary excretion was a minor route of elimination (median, 14.4% [8.8-17.7%]). Parent compound was the main constituent in excreta (45% [feces] and 7% [urine] of the radioactive dose). M506 was the only major metabolite. In part B, absolute bioavailability was 72% (range, 62-81%) after oral administration of 500 mg tablets (the dose and formulation used in phase II trials). In conclusion, tepotinib and its metabolites are mainly excreted via feces; parent drug is the major eliminated constituent. Oral bioavailability of tepotinib is high, supporting the use of the current tablet formulation in clinical trials. Tepotinib was well tolerated in this study with healthy volunteers.

Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10-1000 ng/mL), with adequate accuracy (90.1-114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)