Clinical Pharmacokinetic Interaction Research Articles

Unveiling Pharmacokinetics and Drug Interaction of Linagliptin and Pioglitazone HCl in Rat Plasma Using LC-MS/MS.

The linagliptin (LIN) and pioglitazone HCl (PIO) combination, currently undergoing phase III clinical trials for diabetes mellitus treatment, demonstrated significant improvements in glycemic control. However, the absence of an analytical method for simultaneous determination in biological fluids highlights a crucial gap. This underscores the pressing need for sensitive bioanalytical methods, emphasizing the paramount importance of developing such tools to advance diabetes management strategies and enhance patient care. Herein, a sensitive reverse-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed for simultaneous determination of LIN and PIO in rat plasma using alogliptin as an internal standard. Chromatographic separation was performed on an Agilent Eclipse Plus C18 (4.6 × 100 mm, 3.5 μm) using an isocratic mobile phase system consisting of ammonium formate (pH 4.5) and methanol using an acetonitrile-induced protein precipitation technique for sample preparation. Multiple reaction monitoring in positive ion mode was used for quantitation of the precursor to production at m/z 473.2 → 419.9 for LIN, 357.1 → 134.2 for PIO, and 340.3 → 116.1 for ALO. The linearity range was 0.5 to 100 and 1 to 2000 ng/mL for LIN and PIO, respectively. The developed method was validated as per US-FDA guidelines and successfully applied to clinical pharmacokinetic and drug-drug interaction studies with a single oral administration of LIN and PIO in rat plasma. Pharmacokinetic parameters of LIN were significantly influenced by the concomitant administration of PIO and vice versa. Molecular modeling revealed the significant interaction of LIN and PIO with P-glycoprotein. Therefore, the drug-drug interaction between LIN and PIO deserves further study to improve drug therapy and prevent dangerous adverse effects.

Assessment of the clinical pharmacokinetic interaction potential mediated So-Cheong-Ryong-Tang on a cocktail of anti-inflammatory and anti-biotic drugs, established by physiologically based pharmacokinetic modelings

Assessment of the clinical pharmacokinetic interaction potential mediated So-Cheong-Ryong-Tang on a cocktail of anti-inflammatory and anti-biotic drugs, established by physiologically based pharmacokinetic modelings

Comprehensive Physiologically Based Pharmacokinetic Model to Assess Drug-Drug Interactions of Phenytoin.

Regulatory agencies worldwide expect that clinical pharmacokinetic drug-drug interactions (DDIs) between an investigational new drug and other drugs should be conducted during drug development as part of an adequate assessment of the drug's safety and efficacy. However, it is neither time nor cost efficient to test all possible DDI scenarios clinically. Phenytoin is classified by the Food and Drug Administration as a strong clinical index inducer of CYP3A4, and a moderate sensitive substrate of CYP2C9. A physiologically based pharmacokinetic (PBPK) platform model was developed using GastroPlus® to assess DDIs with phenytoin acting as the victim (CYP2C9, CYP2C19) or perpetrator (CYP3A4). Pharmacokinetic data were obtained from 15 different studies in healthy subjects. The PBPK model of phenytoin explains the contribution of CYP2C9 and CYP2C19 to the formation of 5-(4'-hydroxyphenyl)-5-phenylhydantoin. Furthermore, it accurately recapitulated phenytoin exposure after single and multiple intravenous and oral doses/formulations ranging from 248 to 900 mg, the dose-dependent nonlinearity and the magnitude of the effect of food on phenytoin pharmacokinetics. Once developed and verified, the model was used to characterize and predict phenytoin DDIs with fluconazole, omeprazole and itraconazole, i.e., simulated/observed DDI AUC ratio ranging from 0.89 to 1.25. This study supports the utility of the PBPK approach in informing drug development.

Goldenseal-Mediated Inhibition of Intestinal Uptake Transporters Decreases Metformin Systemic Exposure in Mice

Goldenseal is a perennial plant native to eastern North America. A recent clinical study reported goldenseal decreased metformin Cmax and area under the blood concentration versus time curve (AUC) by 27% and 23%, respectively, but half-life and renal clearance were unchanged. These observations suggested goldenseal altered processes involved in metformin absorption. The underlying mechanism(s) remain(s) unknown. One mechanism for the decreased metformin systemic exposure is inhibition by goldenseal of intestinal uptake transporters involved in metformin absorption. Goldenseal extract and three goldenseal alkaloids (berberine, (-)-β-hydrastine, hydrastinine) were tested as inhibitors of organic cation transporter (OCT) 3, plasma membrane monoamine transporter (PMAT), and thiamine transporter (THTR) 2 using human embryonic kidney 293 cells overexpressing each transporter. The goldenseal extract, normalized to berberine content, was the strongest inhibitor of each transporter (IC50: 4.9, 13.1, and 5.8 μM for OCT3, PMAT, and THTR2, respectively). A pharmacokinetic study in mice compared the effects of berberine, (-)-β-hydrastine, goldenseal extract, and imatinib (OCT inhibitor) on orally administered metformin. Goldenseal extract and imatinib significantly decreased metformin Cmax by 31% and 25%, respectively, and had no effect on half-life. Berberine and (-)-β-hydrastine had no effect on metformin pharmacokinetics, indicating neither alkaloid alone precipitated the interaction in vivo. A follow-up murine study involving intravenous metformin and oral inhibitors examined the contributions of basolateral enteric/hepatic uptake transporters to the goldenseal-metformin interaction. Goldenseal extract and imatinib had no effect on metformin AUC and half-life, suggesting lack of inhibition of basolateral enteric/hepatic uptake transporters. Results may have implications for patients taking goldenseal with drugs that are substrates for OCT3 and THTR2. SIGNIFICANCE STATEMENT: Goldenseal is used to self-treat respiratory infections and digestive disorders. We investigated potential mechanisms for the clinical pharmacokinetic interaction observed between goldenseal and metformin, specifically inhibition by goldenseal of intestinal uptake transporters (OCT3, PMAT, THTR2) involved in metformin absorption. Goldenseal extract inhibited all three transporters in vitro and decreased metformin systemic exposure in mice. These data may have broader implications for patients co-consuming goldenseal with other drugs that are substrates for these transporters.

Pharmacokinetics and Drug-Drug Interaction of Ocedurenone (KBP-5074) in vitro and in vivo.

Ocedurenone (KBP-5074) is a novel nonsteroidal mineralocorticoid receptor antagonist that has demonstrated safety and efficacy in clinical trials in patients with uncontrolled hypertension and stage 3b/4 chronic kidney disease. This study evaluated the involvement of cytochrome P450 (CYP) isozymes and drug transporters in the biotransformation of ocedurenone, and whether ocedurenone inhibited or induced CYP enzymes and transporters. Clinical pharmacokinetic drug-drug interaction (DDI) of ocedurenone with CYP3A inhibitor and inducer were investigated in healthy volunteers. In vitro tests were conducted to determine which CYP enzymes were involved in ocedurenone's metabolism and whether ocedurenone inhibited or induced these CYP enzymes; ocedurenone substrate characteristics for efflux and uptake transporters and its inhibitory potential on major drug transporters were also assessed. A clinical DDI study was conducted in healthy volunteers to evaluate the effects of a strong CYP3A inhibitor (itraconazole) and inducer (rifampin) on ocedurenone's pharmacokinetics. The in vitro study showed that ocedurenone was primarily metabolized by CYP3A4 and that it did not inhibit CYP enzymes. Ocedurenone appeared to be a substrate of BCRP and P-gp efflux transporters and inhibited BCRP, BSEP, MDR1, MATE1 and 2-K, OATP1B1/3, and OCT1. The clinical DDI study showed that itraconazole reduced ocedurenone's oral clearance by 51% and increased area under the plasma concentration-time curve extrapolated to infinity(AUC0-inf) by104%, while rifampin increased its oral clearance by 6.4-fold and decreased plasma AUC0-inf by 84%. Ocedurenone was shown to be a CYP3A substrate, with no inhibition potential on major drug metabolizing CYP enzymes and transporters at clinical efficacious doses. Ocedurenone did not induce CYP1A2 and 3A4 activity in cultured human primary hepatocytes. Clinical DDI study indicated ocedurenone was well tolerated when administered as a single 0.5-mg dose both alone and with itraconazole or rifampin, and while itraconazole had a weak effect on ocedurenone's pharmacokinetics, rifampin had a significant effect reducing systemic exposures.

A clinical pharmacokinetic drug-drug interaction study between dextromethorphan and emvododstat, a potent anti-SARS-CoV-2 dihydroorotate dehydrogenase inhibitor

PurposeA therapeutic agent that targets both viral replication and the hyper-reactive immune response would offer a highly desirable treatment for severe acute respiratory syndrome corona virus 2 (SARS-CoV-2, coronavirus disease 2019, COVID-19) management. Emvododstat (PTC299; 4-chlorophenyl 6-chloro-1-[4-methoxyphenyl]-1,3, 4,9-tetrahydro-2H-pyrido[3,4-b]indole-2-carboxylate) was found to be a potent inhibitor of immunomodulatory and inflammation-related processes by inhibition of dihydroorotate dehydrogenase to reduce the severity of SARS-CoV-2 infections This drug interaction study was performed to determine if emvododstat was an inhibitor of CYP2D6.MethodsPotential drug-drug interactions between emvododstat and a CYP2D6 probe substrate (dextromethorphan) were investigated by measuring plasma dextromethorphan and metabolite (dextrorphan) concentrations before and after emvododstat administration. On day 1, 18 healthy subjects received an oral dose of 30 mg dextromethorphan followed by a 4-day washout period. On day 5, subjects received an oral dose of 250 mg emvododstat with food. Two hours later, 30 mg dextromethorphan was administered.ResultsWhen given with emvododstat, plasma dextromethorphan concentrations increased substantially, while metabolite levels (dextrorphan) remained essentially the same. Maximum plasma dextromethorphan concentration (Cmax) increased from 2006 to 5847 pg/mL. Dextromethorphan exposure (AUC) increased from 18,829 to 157,400 h·pg/mL for AUC0-last and from 21,585 to 362,107 h·pg/mL for AUC0-inf following administration of emvododstat. When dextromethorphan parameters were compared before and after emvododstat, least squares mean ratios (90% confidence interval) were found to be 2.9 (2.2, 3.8), 8.4 (6.1, 11.5), and 14.9 (10.0, 22.1) for Cmax, AUC0-last, and AUC0-inf, respectively.ConclusionEmvododstat appears to be a strong CYP2D6 inhibitor. No drug-related treatment emergent adverse effects (TEAEs) were considered to be severe or serious.Trial registrationEudraCT 2021-004626-29, 11 May 2021.

Adapting regulatory drug‐drug interaction guidance to design clinical pharmacokinetic natural product‐drug interaction studies: A NaPDI Center recommended approach

Pharmacokinetic drug interactions precipitated by botanical and other natural products (NPs) remain critically understudied. Investigating these complex interactions is fraught with difficulties due to the methodologic and technical challenges associated with the inherently complex chemistries and product variability of NPs. This knowledge gap is perpetuated by a continuing absence of a harmonized framework regarding the design of clinical pharmacokinetic studies of NPs and NP‐drug interactions. Accordingly, this Recommended Approach, the fourth in a series of Recommended Approaches released by the Center of Excellence for Natural Product Drug Interaction Research (NaPDI Center), provides recommendations for the design of clinical pharmacokinetic studies involving NPs. Building on prior Recommended Approaches and data generated from the NaPDI Center, such a framework is presented for the design of (1) phase 0 studies to assess the pharmacokinetics of an NP and (2) clinical pharmacokinetic NP‐drug interaction studies. Suggestions for NP sourcing, dosing, study design, participant selection, sampling periods, and data analysis are presented. With the intent to begin addressing the gap between regulatory agencies’ guidance documents about drug‐drug interactions and contemporary NPDI research, the objective of this Recommended Approach is to propose methods for the design of clinical pharmacokinetic studies of NPs and NP‐drug interactions.

Clinical Pharmacokinetic Drug Interaction Potential of MenoAct851 in Adult, Female Healthy Volunteers

MenoAct851 (Varanasi BioResearch Pvt. Ltd., Varanasi, India) is a patented polyherbal formulation developed to manage menopause symptoms that can be taken along with other allopathic medicines. The present study aims to evaluate the drug interaction potential of MenoAct851 to inhibit cytochrome (CY) P450 in vitro in rats, and to measure its effects on simvastatin pharmacokinetic parameters in healthy human volunteers. CYP450-carbon monoxide assay of MenoAct851 was performed in rat liver microsomes to calculate the percentage inhibition. Fluorometric assays of CYP3A4 and CYP2D6 determined half maximal inhibitory concentration value. A double-blind, randomized, placebo-controlled drug interaction study of MenoAct851 was conducted in 24 healthy adult female volunteers aged 25 to 50 years. The selected volunteers were randomized to receive placebo or MenoAct851 500 mg BID PO for 14 days. On the 15th day, each group received 40 mg single-dose simvastatin. Blood samples were drawn at different intervals to measure simvastatin pharmacokinetic parameters. The mean (SD) CYP450 concentration of the diluted microsome sample was calculated and found to be 0.405 (0.12) nmol/mg. The inhibitory potential of MenoAct851 (41.16% [1.24%]) was found to be less than ketoconazole. Half maximal inhibitory concentration values of MenoAct851 on CYP3A4 and CYP2D6 were 11.96 (1.04) µg/mL and 15.24 (0.58) µg/mL, respectively, but they were higher than respective positive controls. There was no statistically significant difference between MenoAct851 and placebo groups concerning the pharmacokinetic parameters such as Cmax, Tmax, t½, and mean residence time of simvastatin; however, AUC showed a significant difference (P < 0.05) between the groups. MenoAct851 produced weaker interaction potential with CYP3A4 and CYP2D6 substrates based on in vitro assays, but the findings of clinical pharmacokinetic analysis indicate that MenoAct851 increased the AUC of simvastatin and simvastatin hydroxy acid. Therefore, coadministration of MenoAct851 might lead to drug-herb interaction, thereby affecting the therapeutic effect of CYP3A4 substrates. (Curr Ther Res Clin Exp. 2020; 81:XXX-XXX).

Drug-drug interaction between crizotinib and entecavir via renal secretory transporter OCT2

Both entecavir and crizotinib are substrates of organic cation transporter 2 (OCT2). The aim of present study was to investigate the mechanisms of drug interactions between these two drugs. Kinetic analysis of entecavir on crizotinib uptake was conduct. Plasma concentration of crizotinib in rats and lung cancer patients, uptake of crizotinib in kidney slices and OCT2 transfected cells, were determined by LC-MS/MS. The clinical pharmacokinetic interactions and impact on adverse reaction of crizotinib in lung cancer patients were investigated. Steady-state through concentration of crizotinib was measured. The crizotinib-related adverse reactions were recorded in lung cancer patients with and without entecavir. Entecavir and 1-methyl-4-phenylpyridinium iodide significantly inhibited the uptake of crizotinib in kidney slices. Kinetic constants for crizotinib uptake by OCT2 were Km 1.16 ± 0.26 µM, Vmax 12.05 ± 0.53 µmol/min mg-1 protein and Ki 9.711 nM. Entecavir can inhibit crizotinib transport by OCT2 in kidney. Co-administration of entecavir significantly reduced the elimination of crizotinib in rats. In lung cancer patients, the steady-state AUCss of crizotinib increased approximately 1.2 fold (p < 0.05) but clearance was decreased by approximately 15% in the presence of entecavir. Steady-state through concentration of crizotinib significantly increased 1.3-fold when co-administrated with entecavir (p>0.001). Co-medication of entecavir significantly (p < 0.05) increased the risks of vision disorders, diarrhea and vomiting 1.6-, 2.3- and 1.8-fold. Entecavir could increase the exposure and reduce the elimination of crizotinib in lung cancer patients. Moreover, the presence of entecavir could significantly increase the incidences of adverse reaction of crizotinib.

Molecular modeling, spectrofluorimetric, and tandem mass spectrometric analysis reveal a competitive binding of amlodipine and rosuvastatin to plasma albumin: Insight into drug-drug interaction

Hyperlipidemia and hypertension are common co-morbidities and considerably increase the risk of cardiovascular complications. The combined treatment has been recommended for decades; the lipid-lowering agents, statins, and calcium channel blockers (CCBs) are commonly prescribed to control the situation. Hence, the development of sensitive assay is of great importance for pharmacokinetic and therapeutic drug monitoring of the combined drugs. Herein, simple and robust chromatography-electrospray ionization-tandem mass spectrometry LC-ESI/MS) method for simultaneous determination of rosuvastatin (ROS) and amlodipine (AML) in rat plasma was developed and fully validated using irbesartan (IRB) as an internal standard (IS). Specimen preparation involved acetonitrile (ACN)-induce protein precipitation followed by gradient elution using 6 mM ammonium formate plus 0.1% formic acid and ACN at a flow rate of 0.4 mL min−1on an Agilent Eclipse Plus ODS (4.6 × 100 mm, 3.5 μm) column. Multiple reaction monitoring in positive ion mode was used for quantitation of precursor ion production at m/z 409.2 → 294.1 & 238.2 for AML, 482.1 → 258.1 for ROS, and 492.1 → 206.9 for IRB. Linearity was observed in the range of 1–5000 ng mL−1 for AML and 1–10,000 ng mL−1 for ROS with detection limits (S/N of 3) of 0.09 and 0.07 ng mL−1 for AML and ROS, respectively. No interference from endogenous substances was detected. The developed method was validated in terms of accuracy, precision, selectivity, recovery, matrix effects, and stability as per US-FDA Bioanalytical guidelines and successfully applied to clinical pharmacokinetic and drug-drug interaction (DDI) studies with a single oral administration of AML and ROS in rat plasma. The peak plasma concentrations (Cmax), area under the concentration-time curve (AUC), and volume of distribution (Vd) of AML was significantly influenced by the co-administration of ROS and vice versa. The data obtained from molecular modeling and spectrofluorimetric studies indicated that AML and ROS are competitively bound to plasma albumin. AML and ROS quenched the intrinsic fluorescence of human serum albumin owing to their binding nearest to tryptophan 214 within the hydrophobic pocket. A potential DDI in cardiovascular complicated patients receiving chronic treatment with AML and ROS thus deserves further attention and study to improve drug therapy and prevent serious side effects.

Risk assessment of substances used in food supplements: the example of the botanical Gymnemasylvestre.

Botanicals and preparations derived from these are among the substances frequently added to foods and food supplements, yet the safety of many botanicals has not been systematically assessed. In the context of the EU‐FORA fellowship programme, the fellow performed an assessment on the safety of the botanical Gymnema sylvestre, in accordance with EFSA's guidance on the assessment of safety of botanicals. Although preparations of G. sylvestre are marketed as food supplements, they may appeal to people who are suffering from metabolic syndrome and/or diabetes mellitus. A scientific literature search was carried out using PubMed/MEDLINE and EMBASE electronic databases. Experience was gained by the fellow in systematic data extraction from scientific publications, structuring of the data and evaluating toxicological key parameters, outcomes of clinical significance, pharmacokinetic and pharmacodynamic interactions, uncertainties and methodological shortcomings of studies. Limited evidence from toxicological in vivo studies and human clinical studies suggested lack of relevant adverse effects of this botanical. However, human studies provided some indications that certain Gymnema extracts may enhance the glucose‐lowering effects of certain antidiabetic drugs. Considering the uncertainties for the composition of different Gymnema preparations, potential herb–drug interactions and the indications of glucose lowering or hypoglycaemic effects, the use of Gymnema‐based food supplements in combination with authorised antidiabetic drugs may be associated with risks. The procedures learned for the safety evaluation of Gymnema may be similarly applied by the fellow for the risk assessment of other substances with nutritional or physiological effect added to foods and food supplements. Furthermore, apart from learning by conducting exercises in risk assessment, the fellow was able to develop other skills (e.g. communication skills), diversify his competencies and expand his network of scientific connections for future collaborations in the field of nutritional risk assessment.

Therapeutic Doses of Eltrombopag do not Inhibit Hepatic BCRP in Healthy Volunteers: Intravenous Ceftriaxone as a Model.

Ceftriaxone elimination occurs through breast cancer resistance transporter (BCRP) and multidrug resistance-associated protein 2 (MRP-2) which are expressed on the canalicular membrane of hepatocytes. Eltrombopag, a thrombopoetin receptor agonist used in the treatment of immune thrombocytopenic purpura, is reported in in vitro studies as an inhibitor of intestinal BCRP but not an inhibitor of hepatic BCRP. Thus, the present study evaluates the effect of therapeutic doses of eltrombopag on the clinical pharmacokinetics of intravenous ceftriaxone. Healthy adult (n=12) were treated with oral doses of eltrombopag (0, 25 or 50 mg) 28 and 4 h prior to intravenous ceftriaxone administration (1g). Serial blood samples were collected up to 48 h after ceftriaxone administration and plasma samples were analysed by LC-MS/MS using 50 μL aliquots (total concentration) and 100 μL (unbound concentration). A method to analyze total and unbound ceftriaxone in plasma using LC-MS/MS was developed and validated with linearity from 1 to 200 μg/mL. Both methods are sensitive, precise and accurate with coefficients of variation less than 15% in the study of inter- and intra-assay precision and accuracy. Ceftriaxone pharmacokinetics in healthy adults were described using a bicompartmental model, with a mean clearance of 0.96 L/h (CI95% 0.71-1.20) and AUC0-∞of 1106 mg.h/mL (CI95% 811-1400) for volunteers that received only ceftriaxone; clearance of 0.95 L/h (CI95% 0.77-1.13) and AUC0-∞ of 1083 mg.h/mL (CI95% 876-1290) for volunteers that received ceftriaxone plus 25 mg of eltrombopag and clearance of 0.96 L/h (CI95% 0.74-1.19) and AUC0-∞ of 1072 mg.h/mL (CI95% 872-1273) for volunteers that received ceftriaxone plus 50 mg of eltrombopag. The results do not support the existence of a clinical pharmacokinetic drug interaction involving hepatic BCRP in human subjects receiving intravenous ceftriaxone and oral eltrombopag.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Inhibitory effects of sulfonylureas and non-steroidal anti-inflammatory drugs on in vitro metabolism of canagliflozin in human liver microsomes.

Canagliflozin, used to treat type 2 diabetes mellitus (T2DM), is commonly co-administered with sulfonylureas. The objective of the present study was to evaluate the possible inhibitory effect of sulfonylureas and non-steroidal anti-inflammatory drugs (NSAIDs) on canagliflozin metabolism in vitro. Three sulfonylurea derivatives were evaluated as inhibitors: chlorpropamide, glimepiride and gliclazide. Two other NSAIDs were used as positive control inhibitors: niflumic acid and diclofenac. The rate of formation of canagliflozin metabolites was determined by HPLC analysis of in vitro incubations of canagliflozin as a substrate with and without inhibitors, using human liver microsomes (HLMs). Among sulfonylureas, glimepiride showed the most potent inhibitory effect against canagliflozin M7 metabolite formation, with an IC50 value of 88μm, compared to chlorpropamide and gliclazide with IC50 values of more than 500μm. Diclofenac inhibited M5 metabolite formation more than M7, with IC50 values of 32μm for M5 and 80μm for M7. Niflumic acid showed no inhibition activity against M5 formation, but had relatively selective inhibitory potency against M7 formation, which is catalysed by UGT1A9, with an IC50 value of 1.9μm and an inhibition constant value of 0.8μm. A clinical pharmacokinetic interaction between canagliflozin and sulfonylureas is unlikely. However, a possible clinically important drug interaction between niflumic acid and canagliflozin has been identified.

An Overview of Pharmacokinetic Considerations for the Use of Artemisinin-Based Combinations in Three Unique Populations

Malaria continues to be a global health burden and one of the most common infectious diseases worldwide. Treatment consists of artemisinin-based combination regimens that utilize pharmacokinetic principles to ensure optimal efficacy. Many pharmacokinetic considerations exist for these agents, including use in special populations and coadministration with agents prone to drug–drug interactions. This review provides an overview of pharmacokinetic considerations of artemisinin-based combinations. Key topics discussed include pharmacokinetic rationale for combinations of artemisinin agents with partner drugs, implications for dosing considerations with children, pharmacokinetic changes associated with pregnancy and known clinical pharmacokinetic interactions between antimalarials and other commonly used medications.

Clinical Pharmacokinetics and Pharmacodynamics of Bosutinib.

Chronic myeloid leukemia (CML) is a clonal myeloproliferative stem cell disorder. Bosutinib is an oral, once-daily SRC/ABL tyrosine kinase inhibitor with very potent inhibitory activity. Bosutinib is effective against all phases of intolerant or resistant Philadelphia chromosome-positive CML that do not harbor the T315I or V299LABL kinase domain mutations. Peak plasma concentrations of bosutinib occur at 4-6 h following oral administration, and dose-proportional increases in exposure are observed at doses ranging from 200 to 800mg. Absorption of bosutinib increases with food. Bosutinib is distributed extensively into the tissues. It is highly plasma protein bound (94%) and is primarily metabolized in the liver by cytochrome P450 3A4. Bosutinib is well tolerated overall and has a unique but manageable toxicity profile. This article provides a review of the available clinical pharmacokinetic, pharmacodynamic, and drug-drug interaction data on bosutinib in healthy subjects, patients with CML, and special populations.

Clinical Drug-Drug Pharmacokinetic Interaction Potential of Sucralfate with Other Drugs: Review and Perspectives.

Sucralfate, a complex of aluminium hydroxide with sulfated sucrose, forms a strong gastrointestinal tract (GIT) mucosal barrier with excellent anti-ulcer property. Because sucralfate does not undergo any significant oral absorption, sucralfate resides in the GIT for a considerable length of time. The unabsorbed sucralfate may alter the pharmacokinetics of the oral drugs by impeding its absorption and reducing the oral bioavailability. Because of the increased use of sucralfate, it was important to provide a reappraisal of the published clinical drug-drug interaction studies of sucralfate with scores of drugs. This review covers several category of drugs such as non-steroidal anti-inflammatory drugs, fluoroquinolones, histamine H2-receptor blockers, macrolides, anti-fungals, anti-diabetics, salicylic acid derivatives, steroidal anti-inflammatory drugs and provides pharmacokinetic data summary along with study design, objectives and key remarks. While the loss of oral bioavailability was significant for the fluoroquinolone class, it generally varied for other classes of drugs, suggesting that impact of the co-administration of sucralfate is manageable in clinical situations. Given the technology advancement in formulation development, it may be in order feasible to develop appropriate formulation strategies to either avoid or minimize the absorption-related issues when co-administered with sucralfate. It is recommended that consideration of both in vitro and preclinical studies may be in order to gauge the level of interaction of a drug with sucralfate. Such data may aid in the development of appropriate strategies to navigate the co-administration of sucralfate with other drugs in this age of polypharmacy.

Abstract C2: Clinical safety, pharmacokinetics and early evidence of activity of the oral IAPs inhibitor Debio 1143 in combination with carboplatin and paclitaxel: a phase Ib study

Abstract Background: Resistance to apoptosis is a typical hallmark of cancer. Inhibitor of Apoptosis Proteins (IAPs) block caspase activation, modulate NF-kB signaling pathways, and are involved in resistance to standard chemo and radiation therapies. As such, IAPs antagonism represents an attractive target for therapeutic intervention. Debio 1143 is a potent orally-available monovalent SMAC mimetic antagonist of IAPs currently in clinical development. A previous phase I study showed Debio 1143 was well tolerated up to 900 mg QD as a single agent, with strong evidence of pharmacodynamic (PD) activity and appropriate pharmacokinetic (PK) disposition at doses ≥ 120 mg. [1] This Phase I study defined the dose limiting toxicities (DLTs), maximum tolerated dose (MTD), safety, PK, and PD of Debio 1143 in combination with carboplatin and paclitaxel. Methods: Treatment-naïve and previously treated patients with squamous non-small cell lung cancer (NSCLC), and previously treated patients with triple negative breast cancer (TNBC) and platinum-resistant epithelial ovarian cancer (EOC) were treated with carboplatin (AUC 6) and paclitaxel 175 mg/m2 on day 1 of every 21-day-cycle up to a maximum of 6 cycles, combined with escalating doses of Debio 1143, administered once daily on days 1-5 of every 21-day cycle. The starting dose of Debio 1143 was 200 mg QD. Results: Thirty-one patients were included in the study. Four patients are still on treatment. Hematological DLTs were observed in 2/4 patients in the first two dose levels despite the reduction of Debio 1143 dose to 100 mg. PK data suggested a PK interaction between Debio 1143 and paclitaxel. The study protocol was amended to reduce the doses of carboplatin to AUC 5 and paclitaxel to 135 mg/m2. Afterwards, patients received Debio 1143 doses of 100 mg (n = 2), 125 mg (n = 2), 175 mg (n = 2), 200 mg (n = 7), 225 mg (n = 5), 250 mg (n = 9). DLTs were febrile neutropenia (n = 2) and G3 ALT increase (n = 1). The MTD of Debio 1143 to be combined with carboplatin (AUC 5) and paclitaxel (135 mg/m2) is 250 mg QD. Most common treatment-related AEs reported in ≥ 15% of patients were asthenia (n = 13), decreased appetite (n = 11), diarrhea (n = 9), neutropenia (n = 9), thrombocytopenia (n = 8), anemia (n = 8), nausea (n = 7), fatigue (n = 7), vomiting (n = 4), AST increase (n = 4), hypomagnesaemia (n = 4), myalgia (n = 4),and epistaxis (n = 4). Paclitaxel exposure in patients dosed at 135 mg/m2 in combination with Debio 1143 was similar to historical control dosed at 175 mg/m2 due to a 25 to 40% reduction in clearance. Preliminary evaluation of PD endpoints confirmed Debio 1143-induced cIAP1 degradation in PBMCs at doses starting from 100mg. In line with the expected mechanism of action, modulation of serum PD markers of NF-kB signaling pathways and epithelial apoptosis was also observed during treatment. Twenty-three patients were evaluable for response. Partial responses by RECIST have been observed in 7 patients with EOC (6/17) and TNBC (1/5). Conclusions: The combination of Debio 1143 with carboplatin and paclitaxel is well tolerated, with significant PD activity and hints of activity. The clinical PK interaction between Debio 1143 and paclitaxel is well-controlled and managed in the patients. These findings support a further Phase II program. [1] HI Hurwitz et al., Cancer Chemother Pharmacol (2015) 75:851 Citation Format: Isabelle Ray-Coquard, Christophe Le Tourneau, Nicolas Isambert, Carlos A. Gomez-Roca, Philippe Cassier, Marie Paule Sablin, Bruno Gavillet, Daniela Purcea, Elisabeth Rouits, Claudia Schusterbauer, Claudio Zanna, Pierre Fumoleau, Jean-Pierre Delord. Clinical safety, pharmacokinetics and early evidence of activity of the oral IAPs inhibitor Debio 1143 in combination with carboplatin and paclitaxel: a phase Ib study. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C2.

Clinical Pharmacokinetic Drug Interactions Associated with Artemisinin Derivatives and HIV-Antivirals

Management of HIV and malaria co-infection is challenging due to potential drug-drug interactions between antimalarial and HIV-antiviral drugs. Little is known of the clinical significance of these drug interactions, and this review provides a comprehensive summary and critical evaluation of the literature. Specifically, drug interactions between WHO-recommended artemisinin combination therapies (ACT) and HIV-antivirals are discussed. An extensive literature search produced eight articles detailing n=44 individual pharmacokinetic interactions. Only data pertaining to artemether-lumefantrine and two other artesunate combinations are available, but most of the interactions are characterized on at least two occasions by two different groups. Overall, protease inhibitors (PIs) tended to increase the exposure of lumefantrine and decrease the exposures of artemether and dihydroartemisinin, a pharmacologically active metabolite of artemether. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) tended to decrease the exposures of artemether, dihydroartemisinin, and lumefantrine when co-administered with artemether-lumefantrine. Fewer studies characterized the effects of PIs or NNRTIs on artesunate combinations, but nevirapine increased artesunate exposure and ritonavir decreased dihydroartemisinin exposure. On the other hand, artemether-lumefantrine or artesunate combinations had little effect on the pharmacokinetics of HIV-antivirals, with the exception of decreased nevirapine exposure from artemether-lumefantrine or increased ritonavir exposure from pyronaridine/artesunate co-administration. In general, pharmacokinetic interactions can be explained by the metabolic properties of the co-administered drugs. Despite several limitations to the studies, these data do provide valuable insights into the potential pharmacokinetic perturbations, and the consistently marked elevation or reduction in ACT exposure in some cases cannot be overlooked.

Therapeutic Protein Drug–Drug Interactions: Navigating the Knowledge Gaps–Highlights from the 2012 AAPS NBC Roundtable and IQ Consortium/FDA Workshop

The investigation of therapeutic protein drug-drug interactions has proven to be challenging. In May 2012, a roundtable was held at the American Association of Pharmaceutical Scientists National Biotechnology Conference to discuss the challenges of preclinical assessment and in vitro to in vivo extrapolation of these interactions. Several weeks later, a 2-day workshop co-sponsored by the U.S. Food and Drug Administration and the International Consortium for Innovation and Quality in Pharmaceutical Development was held to facilitate better understanding of the current science, investigative approaches and knowledge gaps in this field. Both meetings focused primarily on drug interactions involving therapeutic proteins that are pro-inflammatory cytokines or cytokine modulators. In this meeting synopsis, we provide highlights from both meetings and summarize observations and recommendations that were developed to reflect the current state of the art thinking, including a four-step risk assessment that could be used to determine the need (or not) for a dedicated clinical pharmacokinetic interaction study.

Time-Dependent Inhibition and Estimation of CYP3A Clinical Pharmacokinetic Drug-Drug Interactions Using Plated Human Cell Systems

The current studies assessed the utility of freshly plated hepatocytes, cryopreserved plated hepatocytes, and cryopreserved plated HepaRG cells for the estimation of inactivation parameters k(inact) and K(I) for CYP3A. This was achieved using a subset of CYP3A time-dependent inhibitors (fluoxetine, verapamil, clarithromycin, troleandomycin, and mibefradil) representing a range of potencies. The estimated k(inact) and K(I) values for each time-dependent inhibitor were compared with those obtained using human liver microsomes and used to estimate the magnitude of clinical pharmacokinetic drug-drug interaction (DDI). The inactivation kinetic parameter, k(inact), was most consistent across systems tested for clarithromycin, verapamil, and troleandomycin, with a high k(inact) of 0.91 min(-1) observed for mibefradil in HepaRG cells. The apparent K(I) estimates derived from the various systems displayed a range of variability from 3-fold for clarithromycin (5.4-17.7 μM) to 6-fold for verapamil (1.9-12.6 μM). In general, the inactivation kinetic parameters derived from the cell systems tested fairly replicated what was observed in time-dependent inhibition studies using human liver microsomes. Despite some of the observed differences in inactivation kinetic parameters, the estimated DDIs derived from each of the tested systems generally agreed with the clinically reported DDI within approximately 2-fold. In addition, a plated cell approach offered the ability to conduct longer primary incubations (greater than 30 min), which afforded improved ability to identify the weak time-dependent inhibitor fluoxetine. Overall, results from these studies suggest that in vitro inactivation parameters generated from plated cell systems may be a practical approach for identifying time-dependent inhibitors and for estimating the magnitude of clinical DDIs.