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Napabucasin is an orally administered reactive oxygen species generator that is bioactivated by the intracellular antioxidant nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1. Napabucasin induces cell death in cancer cells, including cancer stem cells. This phase 1 study (NCT03411122) evaluated napabucasin drug‐drug interaction potential for 7 cytochrome P450 (CYP) enzymes and the breast cancer resistance protein transporter/organic anion transporter 3. Healthy volunteers who tolerated napabucasin during period 1 received probe drugs during period 2, and in period 3 received napabucasin (240 mg twice daily; days 1‐11) plus a phenotyping cocktail containing omeprazole (CYP2C19), caffeine (CYP1A2), flurbiprofen (CYP2C9), bupropion (CYP2B6), dextromethorphan (CYP2D6), midazolam (CYP3A) (all oral; day 6), intravenous midazolam (day 7), repaglinide (CYP2C8; day 8), and rosuvastatin (breast cancer resistance protein/organic anion transporter 3; day 9). Drug‐drug interaction potential was evaluated in 17 of 30 enrolled volunteers. Napabucasin coadministration increased the area under the plasma concentration–time curve from time 0 extrapolated to infinity (geometric mean ratio [90% confidence interval]) of caffeine (124% [109.0%‐141.4%]), intravenous midazolam (118% [94.4%‐147.3%]), repaglinide (127% [104.7%‐153.3%]), and rosuvastatin (213% [42.5%‐1068.3%]) and decreased the area under the plasma concentration–time curve from time 0 extrapolated to infinity of dextromethorphan (71% [47.1%‐108.3%]), bupropion (79% [64.6%‐97.0%]), and hydroxybupropion (45% [15.7%‐129.6%]). No serious adverse events/deaths were reported. Generally, napabucasin is not expected to induce/inhibit drug clearance to a clinically meaningful degree.

Azeliragon is an inhibitor of the receptor for advanced glycation end products being developed for the treatment of Alzheimer's disease. The objective of the current analysis was to evaluate the relationship between plasma azeliragon concentrations and QT interval. Simultaneous QT values and plasma concentrations were available from 711 subjects (6236 records), pooled from 5 studies in healthy volunteers, 2 studies in patients with mild to moderate Alzheimer's disease, and 1 study in patients with type 2 diabetes and persistent albuminuria. Nonlinear mixed-effects modeling was conducted to describe azeliragon concentration-related changes in QT interval, after correcting for heart rate, using Fridericia's criteria (QTcF) and sex-related differences in baseline QTcF. Azeliragon-related changes in QTcF were predicted using 2 methods: simulation and bias-corrected 90% confidence interval approaches. A small positive relationship between azeliragon plasma concentration and QTcF was noted with a slope of 0.059 ms/ng/mL. Simulations predicted mean (90% prediction interval) changes in QTcF of 0.733 milliseconds (0.32-1.66 milliseconds) with the phase 3 dose (5 mg once daily steady state) and 4.32 milliseconds (1.7-8.74 milliseconds) at supratherapeutic doses (20 mg once daily steady state or 60 mg once daily × 6 days). Bias-corrected upper 90% confidence intervals for therapeutic and supratherapeutic doses were 0.88 and 5.01 milliseconds, respectively. Model-based analysis showed a small, nonclinically meaningful, positive relationship between azeliragon plasma concentration and QTcF with a slope close to zero. Neither the prediction interval nor the upper bound of the 90% confidence interval reached 10 milliseconds, demonstrating no clinically meaningful drug-related effect on QTcF at expected therapeutic and supratherapeutic doses of azeliragon.

Introduction In a pivotal study, apomorphine sublingual film (APL; KYNMOBI®) was an effective and generally well-tolerated on-demand treatment of “OFF” episodes in patients with Parkinson’s disease (PD), approved across the dose range of 10–30 mg. Pharmacokinetics and comparative bioavailability of APL and two subcutaneous (SC) apomorphine formulations (SC-APO [APOKYN®] and SC-APO-GO [APO-go® PEN]) were evaluated in a randomized, three-way crossover, open-label study (NCT03292016). Methods Patients with PD and “OFF” episodes received an open-label randomized sequence of single doses of SC-APO and SC-APO-GO at the currently prescribed dose (2/3/4/5 mg) and APL doses with similar plasma exposure (15/20/25/30 mg) with ≥ 1-day washout between formulations. Plasma pharmacokinetics of apomorphine and apomorphine sulfate (major inactive metabolite) were measured 0–6 h postdose. Results Median time to maximum plasma concentration (tmax) of apomorphine was 0.63–0.75 h for APL and 0.25–0.38 h for SC-APO and SC-APO-GO. Geometric mean maximum plasma concentration (Cmax) of apomorphine was 4.31–11.2 ng/ml across APL doses and was generally lower compared with SC apomorphine formulations within dose groups. Area under the concentration-time curve from time 0 to infinity (AUC∞) was similar across apomorphine formulations within most dose groups. Relative bioavailability of APL was ~ 17% of SC apomorphine by AUC∞; SC-APO and SC-APO-GO had similar bioavailability (98% and 83% by AUC∞ and Cmax, respectively). Apomorphine sulfate exposure was ~ three-fold higher for APL versus SC-APO and SC-APO-GO by AUC∞ and Cmax. Conclusion In patients with PD and “OFF” episodes, APL demonstrated lower Cmax and relative bioavailability but similar exposures (AUCs) versus SC apomorphine within the approved dose range. Trial Registration ClinicalTrials.gov, NCT03292016. Supplementary Information The online version contains supplementary material available at 10.1007/s40120-021-00251-6.

The pharmacokinetics (PKs) of sodium oxybate (SXB) was evaluated in a subset of participants from a study of SXB treatment in children (aged 7-11 years; n = 11) and adolescents (aged 12-17 years; n = 18) with narcolepsy with cataplexy. PK evaluation was conducted over 2 nights during the period when participants received a stable nightly SXB dose. The SXB dose on night 1 was half of night 2 and was administered in two equally divided doses: dose 1 was administered > 2 hours after the evening meal, and dose 2 was administered ≥ 4 hours after dose 1. Noncompartmental PK analysis demonstrated higher plasma concentrations post-dose 2 vs. post-dose 1, higher than dose-proportional increases in area under the concentration-time curve from 0 to 4 hours (AUC0-4h ) after dose 1, indicating nonlinear clearance, and better correlation between exposure and mg/kg than exposure and gram dose. To confirm the noncompartmental findings, identify factors affecting SXB PK, and compare with prior results in adults, a population PK (PopPK) model was established combining PK data from the current study with prior data from adults (132 healthy volunteers and 13 with narcolepsy). A two-compartment PopPK model with first-order absorption and nonlinear clearance from the central compartment described the data well. PopPK identified weight as the main intrinsic factor and food as the main extrinsic factor affecting SXB PK, and predicts similar PK profiles on a mg/kg basis across ages. These results, along with previously reported efficacy and safety outcomes, support weight-based SXB dose initiation in pediatric patients.

142 Background: Napabucasin is an NQO1-bioactivatable investigational agent hypothesized to affect multiple oncogenic cellular pathways including pSTAT3 through the generation of reactive oxygen species. This phase 1 open-label study evaluated the DDI potential of napabucasin and its major metabolite (M1) with respect to 7 major human drug cytochrome P450 (CYP) enzymes and the breast cancer resistance protein (BCRP) transporter. Methods: Healthy adult subjects who initially demonstrated they could tolerate administration of 240 or 480 mg twice daily (BID) napabucasin over 2-days (D) received single doses of the CYP and transporter substrates, followed by ≥7-day washout. In the DDI portion, subjects received napabucasin 240 mg BID on D1–11 with the phenotyping cocktail administered on D6 (omeprazole [CYP2C19] 20 mg, caffeine [CYP1A2] 100 mg, flurbiprofen [CYP2C9] 50 mg, bupropion [CYP2B6] 150 mg, dextromethorphan [CYP2D6] 30 mg, and oral midazolam [CYP3A] 2 mg), intravenous (IV) midazolam 2 mg on D7, repaglinide (CYP2C8) 0.25 mg on D8, and rosuvastatin (BRCP transporter) 10 mg on D9. Results: DDI potential was evaluated in 17 subjects. Exposure to omeprazole, flurbiprofen, and oral midazolam with (test) or without (reference) napabucasin 240 mg BID were similar. Napabucasin increased exposure (area under the curve to infinity) to caffeine (124%), IV midazolam (118%), repaglinide (127%), and rosuvastatin (213%); and decreased exposure to bupropion (79%) and dextromethorphan (71%). None of these changes were expected to be clinically meaningful. The exposure of the major metabolites of the probe drugs with or without napabucasin or M1 were similar. Of the 17 subjects, 12 (70.6%) reported adverse events (AEs); 58.8% reported gastrointestinal disorders. One patient had a grade 3 AE (neutrophil count low); no serious AEs were observed. Conclusions: The data suggest minimal in vivo DDI potential for napabucasin with respect to 7 major human drug CYP enzymes and the BCRP transporter. Napabucasin 240 mg BID was generally tolerable in healthy subjects. Co-administration of napabucasin with CYP and transporter substrates was safe and tolerable. Clinical trial information: NCT03411122.

C. elegans has been widely used as a model organism for programmed cell death and apoptosis. Although the CED-3 caspase is the primary effector of cell death in C. elegans, no selective inhibitors have been identified. Utilizing high-throughput screening with recombinant C. elegans CED-3 protein, we have discovered and confirmed 21 novel small molecule inhibitors. Six compounds had IC50 values < 10 μM. From these, four distinct chemotypes were identified. The inhibitor scaffolds described here could lead to the development of selective molecular probes to facilitate our understanding of programmed cell death in this model organism.

Azeliragon is an inhibitor of the receptor for advanced glycation end products being developed for the treatment of Alzheimer's disease. The objective of the current analysis was to evaluate the relationship between plasma azeliragon concentrations and QT interval. Simultaneous QT values and plasma concentrations were available from 711 subjects (6236 records), pooled from 5 studies in healthy volunteers, 2 studies in patients with mild to moderate Alzheimer's disease, and 1 study in patients with type 2 diabetes and persistent albuminuria. Nonlinear mixed-effects modeling was conducted to describe azeliragon concentration-related changes in QT interval, after correcting for heart rate, using Fridericia's criteria (QTcF) and sex-related differences in baseline QTcF. Azeliragon-related changes in QTcF were predicted using 2 methods: simulation and bias-corrected 90% confidence interval approaches. A small positive relationship between azeliragon plasma concentration and QTcF was noted with a slope of 0.059 ms/ng/mL. Simulations predicted mean (90% prediction interval) changes in QTcF of 0.733 milliseconds (0.32-1.66 milliseconds) with the phase 3 dose (5 mg once daily steady state) and 4.32 milliseconds (1.7-8.74 milliseconds) at supratherapeutic doses (20 mg once daily steady state or 60 mg once daily × 6 days). Bias-corrected upper 90% confidence intervals for therapeutic and supratherapeutic doses were 0.88 and 5.01 milliseconds, respectively. Model-based analysis showed a small, nonclinically meaningful, positive relationship between azeliragon plasma concentration and QTcF with a slope close to zero. Neither the prediction interval nor the upper bound of the 90% confidence interval reached 10 milliseconds, demonstrating no clinically meaningful drug-related effect on QTcF at expected therapeutic and supratherapeutic doses of azeliragon.

Supported by a usage history that predates written records and the perception that "natural" ensures safety, herbal products have increasingly been incorporated into Western health care. Consumers often self-administer these products concomitantly with conventional medications without informing their health care provider(s). Such herb-drug combinations can produce untoward effects when the herbal product perturbs the activity of drug metabolizing enzymes and/or transporters. Despite increasing recognition of these types of herb-drug interactions, a standard system for interaction prediction and evaluation is nonexistent. Consequently, the mechanisms underlying herb-drug interactions remain an understudied area of pharmacotherapy. Evaluation of herbal product interaction liability is challenging due to variability in herbal product composition, uncertainty of the causative constituents, and often scant knowledge of causative constituent pharmacokinetics. These limitations are confounded further by the varying perspectives concerning herbal product regulation. Systematic evaluation of herbal product drug interaction liability, as is routine for new drugs under development, necessitates identifying individual constituents from herbal products and characterizing the interaction potential of such constituents. Integration of this information into in silico models that estimate the pharmacokinetics of individual constituents should facilitate prospective identification of herb-drug interactions. These concepts are highlighted with the exemplar herbal products milk thistle and resveratrol. Implementation of this methodology should help provide definitive information to both consumers and clinicians about the risk of adding herbal products to conventional pharmacotherapeutic regimens.

Flavonolignans from milk thistle (Silybum marianum) have been investigated for their cellular modulatory properties, including cancer chemoprevention and hepatoprotection, as an extract (silymarin), as partially purified mixtures (silibinin and isosilibinin), and as pure compounds (a series of seven isomers). One challenge with the use of these compounds in vivo is their relatively short half-life due to conjugation, particularly glucuronidation. In an attempt to generate analogues with improved in vivo properties, particularly reduced metabolic liability, a semi-synthetic series was prepared in which the hydroxy groups of silybin B were alkylated. A total of five methylated analogues of silybin B were synthesized using standard alkylation conditions (dimethyl sulfate and potassium carbonate in acetone), purified using preparative HPLC, and elucidated via spectroscopy and spectrometry. Of the five, one was monomethylated (3), one was dimethylated (4), two were trimethylated (2 and 6), and one was tetramethylated (5). The relative potency of all compounds was determined in a 72 hr growth-inhibition assay against a panel of three prostate cancer cell lines (DU-145, PC-3, and LNCaP) and a human hepatoma cell line (Huh7.5.1) and compared to natural silybin B. Compounds also were evaluated for inhibition of both cytochrome P450 2C9 (CYP2C9) activity in human liver microsomes and hepatitis C virus infection in Huh7.5.1 cells. The monomethyl and dimethyl analogues were shown to have enhanced activity in terms of cytotoxicity, CYP2C9 inhibitory potency, and antiviral activity (up to 6-fold increased potency) compared to the parent compound, silybin B. In total, these data suggested that methylation of flavonolignans can increase bioactivity.

Despite increasing recognition of potential untoward interactions between herbal products and conventional medications, a standard system for prospective assessment of these interactions remains elusive. This information gap was addressed by evaluating the drug interaction liability of the model herbal product milk thistle (Silybum marianum) with the CYP3A probe substrate midazolam. The inhibitory effects of commercially available milk thistle extracts and isolated constituents on midazolam 1′-hydroxylation were screened using human liver and intestinal microsomes. Relative to vehicle, the extract silymarin and constituents silybin A, isosilybin A, isosilybin B, and silychristin at 100 μM demonstrated >50% inhibition of CYP3A activity with at least one microsomal preparation, prompting IC50 determination. The IC50s for isosilybin B and silychristin were ∼60 and 90 μM, respectively, whereas those for the remaining constituents were >100 μM. Extracts and constituents that contained the 1,4-dioxane moiety demonstrated a >1.5-fold shift in IC50 when tested as potential mechanism-based inhibitors. The semipurified extract, silibinin, and the two associated constituents (silybin A and silybin B) demonstrated mechanism-based inhibition of recombinant CYP3A4 (KI, ∼100 μM; kinact, ∼0.20 min−1) but not microsomal CYP3A activity. The maximum predicted increases in midazolam area under the curve using the static mechanistic equation and recombinant CYP3A4 data were 1.75-fold, which may necessitate clinical assessment. Evaluation of the interaction liability of single herbal product constituents, in addition to commercially available extracts, will enable elucidation of mechanisms underlying potential clinically significant herb-drug interactions. Application of this framework to other herbal products would permit predictions of herb-drug interactions and assist in prioritizing clinical evaluation.

Herb-drug interaction predictions remain challenging. Physiologically based pharmacokinetic (PBPK) modeling was used to improve prediction accuracy of potential herb-drug interactions using the semipurified milk thistle preparation, silibinin, as an exemplar herbal product. Interactions between silibinin constituents and the probe substrates warfarin (CYP2C9) and midazolam (CYP3A) were simulated. A low silibinin dose (160 mg/day × 14 days) was predicted to increase midazolam area under the curve (AUC) by 1%, which was corroborated with external data; a higher dose (1,650 mg/day × 7 days) was predicted to increase midazolam and (S)-warfarin AUC by 5% and 4%, respectively. A proof-of-concept clinical study confirmed minimal interaction between high-dose silibinin and both midazolam and (S)-warfarin (9 and 13% increase in AUC, respectively). Unexpectedly, (R)-warfarin AUC decreased (by 15%), but this is unlikely to be clinically important. Application of this PBPK modeling framework to other herb-drug interactions could facilitate development of guidelines for quantitative prediction of clinically relevant interactions.CPT Pharmacometrics Syst. Pharmacol. (2014) 3, e107; doi:10.1038/psp.2013.69; advance online publication 26 March 2014.

Cranberry juice is used routinely, especially among women and the elderly, to prevent and treat urinary tract infections. These individuals are likely to be taking medications concomitantly with cranberry juice, leading to concern about potential drug-dietary substance interactions, particularly in the intestine, which, along with the liver, is rich in expression of the prominent drug metabolizing enzyme, cytochrome P450 3A (CYP3A). Using a systematic in vitro-in vivo approach, a cranberry juice product was identified recently that elicited a pharmacokinetic interaction with the CYP3A probe substrate midazolam in 16 healthy volunteers. Relative to water, a cranberry juice inhibited intestinal first-pass midazolam metabolism. In vitro studies were initiated to identify potential enteric CYP3A inhibitors from cranberry via a bioactivity-directed fractionation approach involving dried whole cranberry [Vaccinium macrocarpon Ait. (Ericaceae)], midazolam, and human intestinal microsomes (HIM). Three triterpenes (maslinic acid, corosolic acid, and ursolic acid) were isolated. The inhibitory potency (IC50) of maslinic acid, corosolic acid, and ursolic acid was 7.4, 8.8, and

Milk thistle (Silybum marianum) is a popular herbal product used for hepatoprotection and chemoprevention. Two commercially available formulations are the crude extract, silymarin, and the semipurified product, silibinin. Silymarin consists of at least seven flavonolignans, of which the most prevalent are the diastereoisomers silybin A and silybin B; silibinin consists only of silybin A and silybin B. Based on a recent clinical study showing an interaction between a silymarin product and the CYP2C9 substrate losartan, the CYP2C9 inhibition properties of silybin A and silybin B and corresponding regioisomers, isosilybin A and isosilybin B, were evaluated using human liver microsomes (HLMs), recombinant CYP2C9 (rCYP2C9) enzymes, and the clinically relevant probe, (S)-warfarin. Silybin B was the most potent inhibitor in HLMs, followed by silybin A, isosilybin B, and isosilybin A (IC(50) of 8.2, 18, 74, and100 microM, respectively). Next, silybin A and silybin B were selected for further characterization. As with HLMs, silybin B was more potent than silybin A toward rCYP2C9 1 (6.7 versus 12 microM), rCYP2C9 2 (9.3 versus 19 microM), and rCYP2C9 3 (2.4 versus 9.3 microM). Using a matrix of five substrate (1-15 microM) and six inhibitor (1-80 microM) concentrations and HLMs, both diastereoisomers inhibited (S)-warfarin 7-hydroxylation in a manner described best by a mixed-type inhibition model (K(i) values of 4.8 and 10 microM for silybin B and silybin A, respectively). These observations, combined with the high systemic silibinin concentrations (5-75 microM) achieved in a phase I study involving prostate cancer patients, prompt clinical evaluation of a potential warfarin-milk thistle interaction.

Ngoc Ngo1, Scott J Brantley1, Daniel R Carrizosa2, Angela DM Kashuba1, E Claire Dees2, David J Kroll3, Nicholas H Oberlies4, Mary F Paine11UNC Eshelman School of Pharmacy and 2Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 3Biomanufacturing Research Institute and Technology Enterprise and the Department of Pharmaceutical Sciences, North Carolina Central University, Durham, NC, USA; 4Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USABackground: Cranberry products have been implicated in several case reports to enhance the anticoagulant effect of warfarin. The mechanism could involve inhibition of the hepatic CYP2C9-mediated metabolic clearance of warfarin by components in cranberry. Because dietary/natural substances vary substantially in bioactive ingredient composition, multiple cranberry products were evaluated in vitro before testing this hypothesis in vivo.Methods: The inhibitory effects of five types of cranberry juices were compared with those of water on CYP2C9 activity (S-warfarin 7-hydroxylation) in human liver microsomes (HLM). The most potent juice was compared with water on S/R-warfarin pharmacokinetics in 16 healthy participants given a single dose of warfarin 10 mg.Results: Only one juice inhibited S-warfarin 7-hydroxylation in HLM in a concentration-dependent manner (P < 0.05), from 20% to >95% at 0.05% to 0.5% juice (v/v), respectively. However, this juice had no effect on the geometric mean AUC00-oo and terminal half-life of S/R-warfarin in human subjects.Conclusions: A cranberry juice that inhibited warfarin metabolism in HLM had no effect on warfarin clearance in healthy participants. The lack of an in vitro–in vivo concordance likely reflects the fact that the site of warfarin metabolism (liver) is remote from the site of exposure to the inhibitory components in the cranberry juice (intestine).Keywords: warfarin, cranberry, interaction, CYP2C9, metabolism, inhibition