Evaluation of drug‐drug interaction potential between omecamtiv mecarbil and rosuvastatin,a BCRP substrate,with a clinical study in healthy subjects and using a physiologically‐based pharmacokinetic model

Omecamtiv mecarbil (OM) is a novel cardiac myosin activator in development for the treatment of heart failure. In vitro, OM is an inhibitor of BCRP. Rosuvastatin, a BCRP substrate, is one of the most commonly prescribed medications in patients with heart failure. The potential for a pharmacokinetic (PK) drug‐drug interaction (DDI) was investigated, specifically to determine whether a single 50 mg dose of OM would impact the PKs of a single 10 mg dose of rosuvastatin in an open‐label study in 14 healthy subjects. The ratios of the geometric least‐square means (90% confidence intervals [CIs]) of rosuvastatin co‐administered with OM compared to rosuvastatin alone were 127.1% (90% CI 113.8–141.9), 132.8% (90% CI 120.7–146.1), and 154.2% (90% CI 132.8–179.1) for area under the plasma‐concentration time curve from time zero to infinity (AUC_inf), area under the plasma‐concentration time curve from time zero to time of last quantifiable concentration (AUC_last), and maximum observed plasma concentration (C_max), respectively. Whereas the DDI study with rosuvastatin was conducted with the co‐administration of a single dose of OM, in the clinical setting, patients receive OM at doses of 25, 37.5, or 50 mg twice daily (b.i.d.). Hence, to extrapolate the results of the DDI study to a clinically relevant scenario of continuous b.i.d. dosing with OM, physiologically‐based pharmacokinetic (PBPK) modeling was performed to explore the potential of BCRP inhibition following continuous b.i.d. dosing of OM at the highest 50 mg dose. Modeling results indicated that following 50 mg b.i.d. dosing of OM, the predicted ratios of the geometric means (90% CIs) for rosuvastatin AUC_inf and C_max were 1.18 (90% CI 1.16–1.20) and 2.04 (90% CI 1.99–2.10), respectively. Therefore, these results suggest that OM, following multiple dose administration, is a weak inhibitor of BCRP substrates and is in accordance with that observed in the single dose OM DDI clinical study.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Omecamtiv mecarbil (OM) is a cardiac myosin activator and is currently under investigation for the treatment of heart failure with reduced ejection fraction.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study investigated the drug‐drug interaction (DDI) potential of OM on the pharmacokinetics of rosuvastatin, a BCRP substrate, using a clinical study and a physiologically‐based pharmacokinetic (PBPK) modeling approach.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

The clinical study and PBPK modeling analyses confirm that OM is expected to be a weak inhibitor of BCRP in the clinical setting.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

This study highlights the DDI potential of single doses of OM for BCRP substrates from a clinical study and demonstrates the importance of the PBPK modeling approach to investigate DDI effects following multiple doses of OM at therapeutic concentrations.     

Safety,tolerability, and pharmacokinetics of oral baicalein tablets in healthy Chinese subjects: A single‐center,randomized, double‐blind,placebo‐controlled multiple‐ascending‐dose study

Baicalein is a biologically important flavonoid in extracted from the Scutellaria baicalensis Georgi, which can effectively inhibit the influenza virus. This study aimed to analyze the safety and pharmacokinetic (PK) characteristics of baicalein tablets in healthy Chinese subjects and provide more information for phase II clinical trials. In this multiple‐ascending‐dose placebo‐controlled trial, 36 healthy subjects were randomized to receive 200, 400, and 600 mg of baicalein tablet or placebo once daily on day 1 and day 10, 3 times daily on days 4–9. All groups were intended to produce safety and tolerability outcomes (lowest dose first). Blood and urine samples were collected from subjects in the 600 mg group for baicalein PK analysis. Our study had shown that Baicalein tablet was generally safe and well‐tolerated. All adverse events were mild and resolved without any intervention except one case of fever reported in the 600 mg group, which was considered as moderate but not related with baicalein as judged by the investigator. Oral baicalein tablets were rapidly absorbed with peak plasma levels being reached within 2 h after multiple administration. The highest urinary excretion of baicalein and its metabolites peaked in 2 h, followed by 12 h, with a double peak trend.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Many studies have shown that baicalin has an anti‐influenza effect in cell and animal experiments. The primary mechanism of action is that baicalein has a strong inhibitory effect on the sialidase of the influenza virus.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study aimed to analyze the safety and pharmacokinetic (PK) characteristics of baicalein tablets in healthy Chinese subjects and provide more information for phase II clinical trials.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Our study results have shown that baicalein tablets were administered multiple times within the studied dose range were safe and well‐tolerated in healthy Chinese subjects with no serious or severe adverse effects. The highest urinary excretion of baicalein and its metabolites peaked in 2 h, followed by 12 h, with a double peak trend. Oral baicalein tablets were rapidly absorbed with peak plasma levels reached within 2 h after multiple administration.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Our study addresses the safety outcomes of baicalein tablets and emphasizes the PKs of baicalein, which provides a better understanding and a scientific basis of the clinical application of baicalein for further evaluation.     

Pharmacokinetics and pharmacodynamics of itepekimab in healthy adults and patients with asthma: Phase I first‐in‐human and first‐in‐patient trials

Itepekimab is a monoclonal antibody that targets interleukin (IL‐33) and has been shown to reduce airway inflammation and associated tissue damage in preclinical studies. We assessed the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamic profiles of single‐ascending and multiple‐ascending doses of itepekimab in two randomized, double‐blind, placebo‐controlled phase I studies. Healthy adults (N = 40) were randomized to the single‐dose study and patients with moderate asthma (N = 23) to the multiple‐dose study. Itepekimab was administered intravenously (0.3, 1, 3, or 10 mg/kg infusion) or subcutaneously (150 mg) in the single‐dose study and subcutaneously (75 or 150 mg weekly for 4 weeks) in the multiple‐dose study. Itepekimab exhibited linear PKs across studies and dose‐proportional increases in mean maximum concentration in serum and area under the concentration–time curve following single intravenous or multiple subcutaneous doses. Itepekimab demonstrated mean subcutaneous bioavailability of 59–73% and a long terminal half‐life (30.0–31.6 days). IL‐33 concentrations in most healthy participants and patients with asthma were undetectable at baseline. Following administration of itepekimab in both studies, total IL‐33 concentrations increased and blood eosinophils decreased, both with durable effect. Itepekimab was well‐tolerated in both studies with no detection of treatment‐emergent anti‐drug antibody responses.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Preclinical data suggest that itepekimab, a monoclonal antibody targeting IL‐33, may benefit patients with chronic inflammatory airway diseases by blocking IL‐33–mediated pathologic inflammation. Neither the pharmacokinetic (PK) profile of itepekimab nor its safety has been fully elucidated in first‐in‐human or first‐in‐patient studies.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The study evaluated the initial safety of itepekimab, and its PK and pharmacodynamic activity in healthy adults and patients with asthma.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Itepekimab demonstrated linear and dose‐proportional PKs in our studies and was well‐tolerated, with no evidence of immunogenicity. These findings have facilitated dose and regimen selection for subsequent clinical studies in patients with asthma and chronic obstructive pulmonary disease.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Itepekimab is one of a few anti‐alarmin biologics under development; if successful, it may provide an alternative mechanism of action with which to target chronic inflammatory airway diseases, alone or in combination with other targeted therapies.     

Required dose of sugammadex or neostigmine for reversal of vecuronium‐induced shallow residual neuromuscular block at a train‐of‐four ratio of 0.3

Residual shallow neuromuscular block (NMB) is potentially harmful and contributes to critical respiratory events. Evidence for the optimal dose of sugammadex required to reverse vecuronium‐induced shallow NMB is scarce. The aims of the present study were to find suitable doses of sugammadex and neostigmine to reverse a residual vecuronium‐induced NMB from a time of flight (TOF) ratio of 0.3–0.9 and evaluate their safety and efficacy. In total, 121 patients aged 18–65 years were randomly assigned to 11 groups to receive placebo, sugammadex (doses of 0.125, 0.25, 0.5, 1.0, or 2.0 mg/kg), or neostigmine (doses of 10, 25, 40, 55, or 70 μg/kg). The reversal time of sugammadex and neostigmine to antagonize a vecuronium‐induced shallow residual NMB (i.e., TOF ratio of 0.3) and related adverse reactions were recorded. Several statistical models were tested to find an appropriate statistical model to explore the suitable doses of sugammadex and neostigmine required to reverse a residual vecuronium‐induced NMB. Based on a monoexponential model with the response variable on a logarithmic scale, sugammadex 0.56 mg/kg may be sufficient to reverse vecuronium‐induced shallow residual NMB at a TOF ratio of 0.3 under anesthesia maintained with propofol. Neostigmine may not provide prompt and satisfactory antagonism as sugammadex, even in shallow NMB.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Sugammadex 4 and 2 mg/kg can effectively reverse deep and moderate neuromuscular blockade (NMB) induced by aminosteroidal NMB agents, respectively. The optimal dose of sugammadex required to reverse vecuronium on shallow NMB has not yet been evaluated, and whether neostigmine can provide the same satisfactory antagonism as sugammadex in vecuronium‐induced shallow NMB remains unknown.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This analysis of a single‐center, randomized, double‐blind trial evaluated biological models to find an appropriate model to explore suitable doses of sugammadex and neostigmine to reverse residual vecuronium‐induced NMB from a time of flight (TOF) ratio of 0.3 to 0.9.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Sugammadex 0.56 mg/kg may be sufficient to reverse vecuronium‐induced shallow residual NMB at a TOF ratio of 0.3 under anesthesia maintained with propofol. Neostigmine may not provide antagonism as satisfactory as the sugammadex dose due to its less stable recovery time and higher incidence of recurarization even in shallow NMB.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

A small dose of sugammadex—0.56 mg/kg—can satisfactorily reverse vecuronium‐induced shallow NMB at a TOF ratio of 0.3. If doctors use the required dose of sugammadex, it will promote rational drug use and avoid some side effects of excessive medication.     

First‐in‐human study of milvexian,an oral,direct, small molecule factor XIa inhibitor

Milvexian (BMS‐986177/JNJ‐70033093) is a small molecule, active‐site inhibitor of factor XIa (FXIa) being developed to prevent and treat thrombotic events. The safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of milvexian were assessed in a two‐part, double‐blind, placebo‐controlled, sequential single ascending dose (SAD) and multiple ascending dose (MAD) study in healthy adults. Participants in SAD panels (6 panels of 8 participants; n = 48) were randomized (3:1) to receive milvexian (4, 20, 60, 200, 300, or 500 mg) or placebo. The 200‐ and 500‐mg panels investigated the pharmacokinetic impact of a high‐fat meal. Participants in MAD panels (7 panels of 8 participants; n = 56) were randomized (3:1) to receive milvexian (once‐ or twice‐daily) or placebo for 14 days. All milvexian dosing regimens were safe and well‐tolerated, with only mild treatment‐emergent adverse events and no clinically significant bleeding events. In SAD panels, maximum milvexian plasma concentration occurred 3 h postdose in all fasted panels. The terminal half‐life (T_1/2) ranged from 8.3 to 13.8 h. In fasted panels from 20 to 200 mg, absorption was dose‐proportional; results at higher doses (300 and 500 mg) were consistent with saturable absorption. Food increased milvexian bioavailability in a dose‐dependent fashion. In MAD panels, steady‐state milvexian plasma concentration was reached within 3 and 6 dosing days with once‐ and twice‐daily dosing, respectively. Renal excretion was less than 20% in all panels. Prolongation of activated partial thromboplastin time was observed and was directly related to drug exposure. These results suggest that the safety, tolerability, PK, and PD properties of milvexian are suitable for further clinical development.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Factor XI (FXI) amplifies thrombin generation and has a limited role in hemostasis. Targeted FXI inhibition may reduce the burden of vascular and thromboembolic diseases while preserving hemostasis.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study evaluated the safety/tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of the selective, direct, small molecule FXIa inhibitor milvexian.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Single and multiple ascending doses of milvexian up to 500 mg were generally safe and well‐tolerated, with no clinically significant bleeding events. Milvexian plasma concentration was dose proportional at doses up to 200 mg q.d. The milvexian half‐life is suitable for q.d. or b.i.d. dosing. Milvexian exhibited low renal excretion and low overall variability in PK and PD parameters.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

These results can inform the future clinical development of milvexian.     

Safety,tolerability, and pharmacokinetics of single‐ and multiple‐dose administration of islatravir (MK‐8591) in adults without HIV

Islatravir (MK‐8591) is a nucleoside analogue in development for the treatment and prevention of HIV‐1. Two phase 1 trials were conducted during initial evaluation of islatravir: rising single doses (Study 1) and rising multiple doses (Study 2) of oral islatravir in male and female participants without HIV (aged 18–60 years). Safety, tolerability, and pharmacokinetics of islatravir (plasma) and islatravir‐triphosphate (peripheral blood mononuclear cells) were assessed. In Study 1, 24 participants, assigned to 1 of 3 panels, received alternating single doses of islatravir in a fasted state from 5 mg to 400 mg, or placebo, over 3 dosing periods; a 30 mg dose was additionally assessed following a high‐fat meal. In Study 2, 8 participants per dose received 3 once‐weekly doses of 10, 30, or 100 mg islatravir or placebo in a fasted state. For each panel in both trials, 6 participants received active drug and 2 received placebo. Islatravir was generally well‐tolerated, with no serious adverse events or discontinuations due to adverse events. Islatravir was rapidly absorbed (median time to maximum plasma concentration 0.5 hours); plasma half‐life was 49–61 h; intracellular islatravir‐triphosphate half‐life was 118–171 h. Plasma exposure increased in an approximately dose‐proportional manner; there was no meaningful food effect. There was a modest degree of intracellular islatravir‐triphosphate accumulation after multiple weekly dosing. After single oral doses of islatravir greater than or equal to 5 mg, intracellular islatravir‐triphosphate levels were comparable to levels associated with efficacy in preclinical studies. These results warrant continued clinical investigation of islatravir.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

​Current HIV treatment and prevention strategies have limitations, and novel agents that offer improved safety and tolerability, a high barrier to HIV resistance, and more convenient dosing regimens are required.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Two phase 1 studies in participants without HIV assessed safety and pharmacokinetics of rising single and multiple doses of oral islatravir, a nucleoside analogue, to support continued development for the treatment and prevention of HIV‐1 infection.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Islatravir was generally well‐tolerated at single doses up to 400 mg. Oral doses of islatravir greater than or equal to 10 mg resulted in intracellular peripheral blood mononuclear cell levels of the active form, islatravir‐triphosphate, comparable to those associated with antiviral efficacy in preclinical studies.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

These studies provide important safety and pharmacokinetic information about islatravir in adults without HIV, which will be used to support further clinical investigation of islatravir for the treatment and prevention of HIV‐1 infection.     

Evaluation of moxifloxacin in canine and non‐human primate telemetry assays: Comparison of QTc interval prolongation by timepoint and concentration‐QTc analysis

The in vivo correct QT (QTc) assay is used by the pharmaceutical industry to characterize the potential for delayed ventricular repolarization and is a core safety assay mentioned in International Conference on Harmonization (ICH) S7B guideline. The typical telemetry study involves a dose‐response analysis of QTc intervals over time using a crossover (CO) design. This method has proven utility but does not include direct integration of pharmacokinetic (PK) data. An alternative approach has been validated and is used routinely in the clinical setting that pairs pharmacodynamic (PD) responses with PK exposure (e.g., concentration‐QTc (C‐QTc) analysis. The goal of our paper was to compare the QTc sensitivity of two experimental approaches in the conscious dog and non‐human primate (NHP) QTc assays. For timepoint analysis, a conventional design using eight animals (8 × 4 CO) to detect moxifloxacin‐induced QTc prolongation was compared to a PK/PD design in a subset (N = 4) of the same animals. The findings demonstrate that both approaches are equally sensitive in detecting threshold QTc prolongation on the order of 10 ms. Both QTc models demonstrated linearity in the QTc prolongation response to moxifloxacin dose escalation (6 to 46 ms). Further, comparison with human QTc findings with moxifloxacin showed agreement and consistent translation across the three species: C‐QTc slope values were 0.7‐ (dog) and 1.2‐ (NHP) fold of the composite human value. In conclusion, our data show that dog and NHP QTc telemetry with an integrated PK arm (C‐QTc) has the potential to supplement clinical evaluation and improve integrated QTc risk assessment.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Typical cardiovascular studies usually employ timepoint analysis. Published in vivo corrected QT (QTc) assay data has exhibited variability in QTc sensitivity that results in challenges in nonclinical‐clinical assessment of translation.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Comparison of nonclinical timepoint and concentration QTc (C‐QTc) analyses and how it relates to clinical moxifloxacin data.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Dog and non‐human primate (NHP) QTc timepoint and C‐QTc analyses detect QTc internal prolongation, have equivalent sensitivity, and improve confidence in these models for proarrhythmic risk mitigation.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Risk assessment in nonclinical models translates well to human thorough QT (TQT) data for moxifloxacin. The new data highlights the value of a high‐quality dog or NHP QTc assay to support clinical risk assessment and regulatory decision making.     

A randomized,double‐blind,placebo‐ and positive‐controlled crossover study of the effects of durlobactam on cardiac repolarization in healthy subjects

Durlobactam (formerly ETX2514) is a diazabicyclooctane β‐lactamase inhibitor that inhibits class A, C, and D β‐lactamases. Sulbactam combined with durlobactam has in vitro and in vivo activity against Acinetobacter baumannii including carbapenem‐ and colistin‐resistant isolates and is being developed for treating serious infections due to A. baumannii. The effect of a single supratherapeutic dose of durlobactam on the heart rate corrected QT interval (QTc) was evaluated in healthy subjects in a placebo‐ and active‐controlled, single‐infusion, three‐way crossover study. Subjects were randomized to 1 of 6 sequences that included a single 3‐h i.v. infusion of durlobactam 4 g (supratherapeutic dose), a single 3‐h i.v. infusion of placebo, and a single 3‐h i.v. infusion of placebo plus a single oral dose of moxifloxacin 400 mg given open‐label at the end of the i.v. infusion. In each treatment period, Holter electrocardiogram (ECG) measurements were obtained from predose through 24 h post‐start of infusion. For the primary ECG end point, placebo‐corrected change‐from‐baseline corrected QT Fridericia’s formula (ΔΔQTcF), no significant change was observed with durlobactam. A concentration‐QT analysis demonstrated no significant effect of durlobactam on ECG parameters, including QT interval prolongation. Thus, durlobactam has a low risk for prolonging the QT interval and is unlikely to produce any proarrhythmic effects.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Drug‐induced prolongation of the QT interval has the potential to cause severe, potentially fatal ventricular arrhythmias. A number of antimicrobial agents, including fluoroquinolones and macrolides, are associated with a low, but clinically significant increased risk of QT prolongation.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study evaluated the effect of a single supratherapeutic dose of durlobactam on the heart rate corrected QT interval in healthy subjects to determine if there were any potentials for proarrhythmic effects.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study found that durlobactam had a low risk for prolonging the QT interval and is unlikely to produce any proarrhythmic effects.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Because durlobactam had a low risk for prolonging the QT interval alone and when co‐administered with sulbactam, clinicians should be confident in administering the combination without risk for proarrhythmic effects.     

Effect of difelikefalin,a selective kappa opioid receptor agonist,on respiratory depression: A randomized,double‐blind,placebo‐controlled trial

Difelikefalin, a selective kappa opioid receptor agonist designed to limit central nervous system (CNS) penetration, is under development for the treatment of pruritus. Its hydrophilic, small‐peptidic structure limits CNS entry, minimizing potential CNS‐mediated adverse events (AEs). This study assessed the effect of difelikefalin on key relevant measures of respiratory depression in healthy volunteers. This single‐center, randomized, double‐blind, placebo‐controlled, three‐way crossover study enrolled healthy, nonsmoking volunteers. Subjects were randomized to 1 of 3 treatment sequences of difelikefalin (1.0 or 5.0 mcg/kg i.v.) or placebo on sequential days with an intervening 24 (±2) h washout period. The primary end points included incidence of increased end‐tidal carbon dioxide (ETCO₂) greater than or equal to 10 mm Hg versus baseline or a level greater than 50 mm Hg sustained greater than or equal to 30 seconds, and incidence of reduction in saturation of peripheral oxygen (SpO₂) to less than 92% sustained greater than or equal to 30 seconds. Secondary end points included incidence of reduced respiratory rate and other safety assessments. Fifteen subjects were randomized and completed the study. No subject on placebo or difelikefalin met the increased ETCO₂ or reduced SpO₂ primary end point criteria for respiratory depression. All respiratory measures in each group remained near baseline values during 4‐h postdose observations. No subject met the reduced respiratory rate criterion or experienced clinically significant changes in ETCO₂, SpO₂, or respiratory rate. The most commonly reported treatment‐emergent AEs (TEAEs; ≥20% of subjects) were paresthesia, hypoesthesia, and somnolence in the difelikefalin arms. All TEAEs were mild and resolved without intervention. Difelikefalin 1.0 and 5.0 mcg/kg i.v. did not produce respiratory depression.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Severe respiratory depression is a life‐threatening complication of inappropriate use of mu opioid receptor agonists. Difelikefalin, a peripherally restricted kappa opioid receptor (KOR) agonist, has not demonstrated evidence of compromised respiratory safety.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study evaluated whether difelikefalin, a selective and potent KOR agonist, induces respiratory depression.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study helps to expand on the safety profile for difelikefalin. Difelikefalin did not produce respiratory depression in healthy volunteers at doses that were 2 to 10 times higher than those observed to be therapeutically effective in clinical trials of patients with chronic kidney disease–associated pruritus.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

KOR agonists may be potentially safe and effective therapeutics. Difelikefalin is currently being evaluated for chronic kidney disease‐associated pruritus and other chronic pruritic conditions.     

First‐in‐human trial assessing the pharmacokinetic‐pharmacodynamic profile of a novel recombinant human chorionic gonadotropin in healthy women and men of reproductive age

The purpose of this first‐in‐human trial was to examine the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of a novel recombinant human chorionic gonadotropin (rhCG; FE 999302, choriogonadotropin beta) to support its clinical development for various therapeutic indications. The single and multiple dose PK of choriogonadotropin beta (CG beta) were evaluated in women and the single dose PK and PD of CG beta were compared to those of CG alfa in men. CG beta was safe and well‐tolerated in all 84 healthy subjects. In women, the area under the curve (AUC) and the peak serum concentration (C_max) increased approximately dose proportionally following single and multiple doses of CG beta. The apparent clearance (CL/F) was ~ 0.5 L/h, the mean terminal half‐life (t_½) ~ 45 h and the apparent distribution volume (V_z/F) ~ 30 L. After single administration in men, the mean AUC was 1.5‐fold greater for CG beta than for CG alfa. Mean C_max and V_z/F were comparable for the 2 preparations. In accordance with the differences in AUC, the CL/F was lower for CG beta (CL/F 0.5 vs. 0.8 L/h), explained by a longer t_½ (47 vs. 32 h). Serum testosterone levels induced by a single dose rhCG reflected the PK profiles with a slight delay, resulting in 59% higher AUC for CG beta. The PK parameters for CG beta were comparable in men and in women. In conclusion, the PK differs between the two rhCG preparations, causing higher exposure and a higher PD response for CG beta, which may require relatively lower therapeutic doses.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Recombinant human chorionic gonadotropin (hCG) is indicated for the treatment of male or female infertility and administered by single or multiple subcutaneous injections.

• WHAT QUESTION DID THIS STUDY ADDRESS?

A new recombinant hCG (rhCG; choriogonadotropin [CG] beta) produced by a human‐derived cell line (PER.C6) is currently in clinical development. The amino acid sequence of the α‐ and β‐chains are identical to the natural sequences and also to that of rhCG expressed by Chinese Hamster Ovary (CHO) cell line (CG alfa), but the glycosylation provided by the PER.C6 and CHO cells is different. In this trial, the pharmacokinetics (PK) of choriogonadotropin beta were assessed in women and men and the PKs and pharmacodynamics (PDs) were compared in men to those of CG alfa.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

It is concluded that the PK of the two rhCG preparations are different, due to a slower clearance of CG beta resulting in a higher PD response.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Further development of CG beta may require lower doses of this potent hCG compared to current therapeutic hCG preparations.     

Propsective evaluation of high‐dose methotrexate pharmacokinetics in adult patients with lymphoma using novel determinants of kidney function

High‐dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single‐center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7‐hydroxy‐MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine‐ or cystatin C‐based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2–75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8–11.3) grams. Median clearance was similar across three dosing levels at 4.5–5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFR_cys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4‐h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C‐based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Methotrexate (MTX) clearance has a relationship with glomerular filtration rate (GFR), which is often calculated using serum creatinine as a surrogate marker of renal clearance; however, kidney function estimation derived from serum creatinine‐based GFR formulas has several known limitations, particularly in patients with cancer.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study attempts to answer the question of which estimated GFR (eGFR) equation has the strongest correlation with MTX clearance.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Results of this study suggest that, when high‐dose MTX is administered, cystatin C based eGFR equations more strongly correlate with MTX clearance than eGFR equations based on serum creatinine alone.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Incorporating cystatin C into baseline evaluation when estimating kidney function has potential to improve MTX safety and optimize MTX exposure.     

The bioequivalence of fixed‐dose combination tablets of bisoprolol and ramipril and its drug‐drug interaction potential

Chronic antihypertensive treatment often includes combination of two or more therapies with complementary mechanism of action targeting different blood pressure (BP) control system. If available, these components are recommended to be administered as a fixed‐dose combination (FDC) to reduce tablet burden, improve adherence and thus BP control. A combination of ramipril (RAMI) and bisoprolol (BISO) is one of the options used in clinical practice and is supported by therapeutic guidelines. The clinical program for a novel BISO/RAMI FDC consisted of two randomized, open‐label, bioequivalence (BE) studies and one drug‐drug interaction (DDI) study. The BE was examined between two FDC strengths of BISO/RAMI (10/10 and 10/5 mg) and the individual reference products administered concomitantly at respective doses after a single oral dose under fasting conditions. In both BE studies, 64 healthy subjects were randomized according to a two‐way crossover design. The DDI study evaluated a potential pharmacokinetic (PK) interaction between BISO 10 mg and RAMI 10 mg following their single or concomitant administrations in 30 healthy subjects under fasting condition. BE for BISO/RAMI 10/5 mg and absence of a clinically relevant PK DDI between BISO and RAMI was demonstrated as the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) for area under the concentration time curve (AUC) and maximum concentration (C_max) remained within the acceptance range of 80.00 to 125.00%. However, BE for BISO/RAMI 10/10 mg was not demonstrated, as the lower bound of the 90% CI of C_max for RAMI was outside the acceptance range of BE. Both drugs administered alone or combined were well‐tolerated. No PK interaction was observed between BISO and RAMI/ramiprilat, since the co‐administration of BISO and RAMI 10 mg single doses resulted in comparable rate and extent of absorption for BISO and RAMI when compared to their individual products.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Bisoprolol (BISO) and ramipril (RAMI) have both well‐characterized pharmacokinetic (PK) properties, however, clinical studies for this fixed‐dose combination (FDC) are limited and as per our knowledge, a potential of PK drug‐drug interactions (DDIs) between both compounds has not been evaluated.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The clinical program was focused on the evaluation of bioequivalence (BE) for two strengths of novel FDCs containing BISO/RAMI in comparison with their free‐combinations and evaluation of potential PK interaction between BISO and RAMI.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

An absence of PK interaction between BISO and RAMI has been demonstrated in the DDI study. The BE studies provided information about in vivo behavior of the FDC, as well as additional PK, and statistical and safety data for BISO and RAMI.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

FDC containing BISO and RAMI may reduce tablet burden, improve adherence to treatment, and blood pressure control in patients with hypertension. The administration of BISO and RAMI is not associated with a risk of PK interaction between both compounds.     

Diagnostic and prognostic capabilities of a biomarker and EMR‐based machine learning algorithm for sepsis

Sepsis is a major cause of mortality among hospitalized patients worldwide. Shorter time to administration of broad‐spectrum antibiotics is associated with improved outcomes, but early recognition of sepsis remains a major challenge. In a two‐center cohort study with prospective sample collection from 1400 adult patients in emergency departments suspected of sepsis, we sought to determine the diagnostic and prognostic capabilities of a machine‐learning algorithm based on clinical data and a set of uncommonly measured biomarkers. Specifically, we demonstrate that a machine‐learning model developed using this dataset outputs a score with not only diagnostic capability but also prognostic power with respect to hospital length of stay (LOS), 30‐day mortality, and 3‐day inpatient re‐admission both in our entire testing cohort and various subpopulations. The area under the receiver operating curve (AUROC) for diagnosis of sepsis was 0.83. Predicted risk scores for patients with septic shock were higher compared with patients with sepsis but without shock (p < 0.0001). Scores for patients with infection and organ dysfunction were higher compared with those without either condition (p < 0.0001). Stratification based on predicted scores of the patients into low, medium, and high‐risk groups showed significant differences in LOS (p < 0.0001), 30‐day mortality (p < 0.0001), and 30‐day inpatient readmission (p < 0.0001). In conclusion, a machine‐learning algorithm based on electronic medical record (EMR) data and three nonroutinely measured biomarkers demonstrated good diagnostic and prognostic capability at the time of initial blood culture.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Sepsis represents significant morbidity, mortality, and cost in modern health care. Timely treatment with antibiotics improves outcomes, but it can be difficult to identify patients with sepsis early on in the clinical course.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Can a machine‐learning algorithm incorporating basic clinical data and nonroutinely measured biomarkers accurately predict sepsis and other related secondary outcomes?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

A machine‐learning algorithm incorporating basic clinical data and nonroutinely measured biomarkers accurately identify sepsis. Meanwhile, a higher score outputted by the algorithm predicts less favorable outcomes with respect to discharge time, 30‐day mortality, and 30‐day inpatient re‐admission.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Earlier treatment of patients who are on a course for poor outcomes has the potential to significantly improve those outcomes. This study suggests that a machine‐learning‐based score may assist clinicians in identifying such patients.     

Identification of small molecules that mitigate vincristine‐induced neurotoxicity while sensitizing leukemia cells to vincristine

Vincristine (VCR) is one of the most widely prescribed medications for treating solid tumors and acute lymphoblastic leukemia (ALL) in children and adults. However, its major dose‐limiting toxicity is peripheral neuropathy that can disrupt curative therapy. Peripheral neuropathy can also persist into adulthood, compromising quality of life of childhood cancer survivors. Reducing VCR‐induced neurotoxicity without compromising its anticancer effects would be ideal. Here, we show that low expression of NHP2L1 is associated with increased sensitivity of primary leukemia cells to VCR, and that concomitant administration of VCR with inhibitors of NHP2L1 increases VCR cytotoxicity in leukemia cells, prolongs survival of ALL xenograft mice, but decreases VCR effects on human‐induced pluripotent stem cell‐derived neurons and mitigates neurotoxicity in mice. These findings offer a strategy for increasing VCR’s antileukemic effects while reducing peripheral neuropathy in patients treated with this widely prescribed medication.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Vincristine (VCR) is a widely prescribed drug, but its use is limited by its main side effect, neurotoxicity. There are currently no strategies to mitigate VCR neurotoxicity without altering its antileukemic effects.

• WHAT QUESTION DID THIS STUDY ADDRESS?

How to improve VCR efficacy while reducing its main side effect, neurotoxicity?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

The present study shows for the first time the possibility of reduced VCR ‐induced neurotoxicity while improving VCR anti‐leukemia effect by using small molecules.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

The current translational study could permit a safer and more efficient use of VCR.     

Model‐based assessments of CYP3A‐mediated drug‐drug interaction risk of milademetan

Milademetan is a small‐molecule inhibitor of murine double minute 2 (MDM2) that is in clinical development for advanced solid tumors and hematological cancers, including liposarcoma and acute myeloid leukemia. Milademetan is a CYP3A and P‐glycoprotein substrate and moderate CYP3A inhibitor. The current study aims to understand the drug‐drug interaction (DDI) risk of milademetan as a CYP3A substrate during its early clinical development. A clinical DDI study of milademetan ({"type":"clinical-trial","attrs":{"text":"NCT03614455","term_id":"NCT03614455"}}NCT03614455) showed that concomitant administration of single‐dose milademetan with the strong CYP3A inhibitor itraconazole or posaconazole increased milademetan mean area under the curve from zero to infinity (AUC_inf) by 2.15‐fold (90% confidence interval [CI], 1.98–2.34) and 2.49‐fold (90% CI, 2.26–2.74), respectively, supporting that the milademetan dose should be reduced by 50% when concomitantly administered with strong CYP3A inhibitors. A physiologically‐based pharmacokinetic (PBPK) model of milademetan was subsequently developed to predict the magnitude of CYP3A‐mediated DDI potential of milademetan with moderate CYP3A inhibitors. The PBPK model predicted an increase in milademetan exposure of 1.72‐fold (90% CI, 1.69–1.76) with fluconazole, 1.91‐fold (90% CI, 1.83–1.99) with erythromycin, and 2.02‐fold (90% CI, 1.93–2.11) with verapamil. In addition, it estimated that milademetan’s original dose (160 mg once daily) could be resumed from its half‐reduced dose 3 days after discontinuation of concomitant strong CYP3A inhibitors. The established PBPK model of milademetan was qualified and considered to be robust enough to support continued development of milademetan.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Milademetan is a CYP3A and P‐gp substrate and moderate CYP3A inhibitor. Evaluation of drug‐drug interaction (DDI) risk of milademetan by combining clinical studies and physiologically‐based pharmacokinetic (PBPK) modeling has not previously been described.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Will milademetan PK be affected by the concomitant administration of strong or moderate CYP3A inhibitors? When can the original dose of milademetan be resumed after the discontinuation of strong CYP3A inhibitors?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study illustrates the use of a clinical DDI study and PBPK modeling in the early clinical development of milademetan to assess DDI risks in scenarios that have not yet been tested clinically at the time.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

PBPK modeling integrates in vitro and clinical data to facilitate the mechanistic understanding of PKs. Recommendations from PBPK modeling can support the design of clinical studies for the investigation of DDIs.     

Evaluation of the abuse potential of difelikefalin,a selective kappa‐opioid receptor agonist,in recreational polydrug users

Difelikefalin, a selective kappa‐opioid receptor agonist with limited central nervous system penetration, is being developed for the treatment of chronic pruritic conditions. This randomized, double‐blind, active‐ and placebo‐controlled, four‐way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users. Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg); pentazocine (0.5 mg/kg), a schedule IV mu‐opioid partial agonist and kappa‐opioid receptor agonist; and placebo. The abuse potential of difelikefalin was compared with pentazocine and placebo using the maximal score (maximum effect [E_max]) of the Drug Liking visual analog scale (VAS; primary end point), along with multiple secondary end points of subject‐rated measures and pupillometry. Difelikefalin produced significantly lower Drug Liking VAS E_max, and lower peak positive, sedative, and perceptual effects compared with pentazocine. These effects of difelikefalin were small, brief, and not dose‐dependent, although marginally greater than those observed with placebo. Neither dose of difelikefalin elicited significant negative or hallucinogenic effects. On end‐of‐session measures of overall drug liking and willingness to take the drug again, difelikefalin did not differ from placebo, indicating subjects neither liked nor disliked the effects overall and did not feel motivated to take the drug again. Consistent with its lack of mu agonist activity, difelikefalin did not induce miosis compared with pentazocine. All treatments were generally well‐tolerated. This study indicates that difelikefalin presents a low potential for abuse.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Difelikefalin is a selective kappa‐opioid receptor agonist with limited central nervous system penetration being developed for the treatment of chronic pruritus. Difelikefalin has no affinity for other opioid receptors and therefore is different from opioid analgesics that predominantly bind to mu opioid receptors.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This randomized, double‐blind, active‐ and placebo‐controlled, four‐way crossover study addressed whether difelikefalin has abuse potential in healthy recreational polydrug users.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Intravenous difelikefalin, at supratherapeutic doses, had an abuse potential profile that was significantly lower than the schedule IV opioid pentazocine, and not meaningfully different from placebo. Difelikefalin did not elicit significant negative or hallucinogenic effects.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

These findings suggest that difelikefalin should not be a target for diversion for recreational use. This has important clinical implications for patients who may require this treatment, and it demonstrates that peripherally restricted kappa‐opioid receptor exhibit fewer adverse effects and toxicities related to abuse over typical opioids.     

Pharmacokinetics and safety of cenobamate,a novel antiseizure medication,in healthy Japanese,and an ethnic comparison with healthy non‐Japanese

Cenobamate (XCOPRI and ONTOZRY) is a novel antiseizure medication for the treatment of focal‐onset seizures. Nonetheless, there is limited information on the pharmacokinetics (PKs), safety, and efficacy of cenobamate in Asian people, including Japanese people. This study aimed to evaluate the PKs and safety of cenobamate after a single oral dose in healthy Japanese subjects and to compare the PKs with that reported in non‐Japanese subjects. A randomized, double‐blind, placebo‐controlled, single ascending dose study was conducted at four dose levels of 50, 100, 200, and 400 mg. Subjects were randomly assigned to cenobamate or placebo in a 6:2 ratio. Cenobamate was rapidly absorbed, reaching its maximum plasma concentration (C_max) in 0.75 to 2.25 h, and was eliminated with a mean half‐life of 37.0 to 57.7 h. The C_max increased dose proportionally, whereas area under the concentration‐time curve increased more than dose proportionally, which was consistent with the findings in non‐Japanese subjects. The systemic exposure of cenobamate was comparable between Japanese and non‐Japanese subjects at all dose levels evaluated. All adverse events were mild in severity, and their incidence did not show dose‐dependent trends. Furthermore, there were no clinically significant issues in safety parameters, including sedation tests, neurologic examinations, and Columbia Suicide Severity Rating Scale interviews. In conclusion, the systemic exposure of cenobamate after a single dose in Japanese subjects increased by dose, which was similar to the pattern in non‐Japanese subjects. In addition, a single dose of cenobamate was well‐tolerated in the dose range of 50 to 400 mg in healthy Japanese subjects.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Cenobamate is a novel antiseizure medication newly approved for the treatment of focal‐onset seizures in the United States and Europe. To date, properties of cenobamate including pharmacokinetics (PKs) have not been extensively studied in Asian people including Japanese people.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study evaluated the PKs and safety of a single oral dose of cenobamate in healthy Japanese subjects and compared the PKs with that in non‐Japanese subjects previously reported.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Cenobamate showed similar PK profiles in Japanese and non‐Japanese subjects, which suggests its negligible ethnic sensitivity. In addition, a single dose of cenobamate was well‐tolerated in healthy Japanese subjects. Our results indicate that the currently approved dosing regimen of cenobamate may also be applicable to Japanese patients with reasonable exposure and tolerability profiles.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Our study bridged the clinical pharmacology gap between ethnicities by providing new findings on the ethnic sensitivity as well as the PKs and safety of cenobamate in Asian people including Japanese people.     

A metabolomic analysis of thiol response for standard and modified N‐acetyl cysteine treatment regimens in patients with acetaminophen overdose

N‐acetylcysteine (NAC) is an antidote to prevent acetaminophen (paracetamol‐APAP)‐induced acute liver injury (ALI). The 3‐bag licensed 20.25 h standard regimen, and a 12 h modified regimen, are used to treat APAP overdose. This study evaluated the redox thiol response and APAP metabolites, in patients with a single APAP overdose treated with either the 20.25 h standard or 12 h modified regimen. We used liquid chromatography tandem mass spectrometry to quantify clinically important oxidative stress biomarkers and APAP metabolites in plasma samples from 45 patients who participated in a randomized controlled trial (SNAP trial). We investigated the time course response of plasma metabolites at predose, 12 h, and 20.25 h post‐start of NAC infusion. The results showed that the 12 h modified regimen resulted in a significant elevation of plasma NAC and cysteine concentrations at 12 h post‐infusion. We found no significant alteration in the metabolism of APAP, mitochondrial, amino acids, and other thiol biomarkers with the two regimens. We examined APAP and purine metabolism in overdose patients who developed ALI. We showed the major APAP‐metabolites and xanthine were significantly higher in patients with ALI. These biomarkers correlated well with alanine aminotransferase activity at admission. Receiver operating characteristic analysis showed that at admission, plasma APAP‐metabolites and xanthine concentrations were predictive for ALI. In conclusion, a significantly higher redox thiol response with the modified NAC regimen at 12 h postdose suggests this regimen may produce greater antioxidant efficacy. At baseline, plasma APAP and purine metabolites may be useful biomarkers for early prediction of APAP‐induced ALI.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

N‐acetylcysteine (NAC) is an effective antidote used to prevent acetaminophen (APAP)‐induced acute liver injury (ALI). The 12 h modified NAC regimen has a lower rate of adverse effects than the 20.25 h standard NAC regimen. However, the effect of NAC regimen on redox thiol and APAP metabolism have not been studied.

• WHAT QUESTION DID THIS STUDY ADDRESS?

What are the effects of modified and standard NAC regimens on circulating thiol biomarkers and APAP metabolites?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Patients who received 12 h modified NAC treatment have significantly higher circulating cysteine concentration at 12 h postinfusion than those who received 20.25 h standard NAC regimen. At baseline, plasma APAP and purine metabolites were significantly higher in patients who developed ALI.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

This study suggests the 12 h modified NAC regimen provides greater antioxidant protection to APAP overdose patients in this time frame allowing further NAC therapy to be targeted earlier to patients at risk. At baseline, plasma APAP and purine metabolites are predictive biomarkers for APAP‐induced ALI.     

Short‐ and long‐term effects of body weight loss following calorie restriction and gastric bypass on CYP3A‐activity – a non‐randomized three‐armed controlled trial

It remains uncertain whether pharmacokinetic changes following Roux‐en‐Y gastric bypass (RYGB) can be attributed to surgery‐induced gastrointestinal alterations per se and/or the subsequent weight loss. The aim was to compare short‐ and long‐term effects of RYGB and calorie restriction on CYP3A‐activity, and cross‐sectionally compare CYP3A‐activity with normal weight to overweight controls using midazolam as probe drug. This three‐armed controlled trial included patients with severe obesity preparing for RYGB (n = 41) or diet‐induced (n = 41) weight‐loss, and controls (n = 18). Both weight‐loss groups underwent a 3‐week low‐energy‐diet (<1200 kcal/day) followed by a 6‐week very‐low‐energy‐diet or RYGB (both <800 kcal/day). Patients were followed for 2 years, with four pharmacokinetic investigations using semisimultaneous oral and intravenous dosing to determine changes in midazolam absolute bioavailability and clearance, within and between groups. The RYGB and diet groups showed similar weight‐loss at week 9 (13 ± 2.4% vs. 11 ± 3.6%), but differed substantially after 2 years (−30 ± 7.0% vs. −3.1 ± 6.3%). At baseline, mean absolute bioavailability and clearance of midazolam were similar in the RYGB and diet groups, but higher compared with controls. On average, absolute bioavailability was unaltered at week 9, but decreased by 40 ± 7.5% in the RYGB group and 32 ± 6.1% in the diet group at year 2 compared with baseline, with no between‐group difference. No difference in clearance was observed over time, nor between groups. In conclusion, neither RYGB per se nor weight loss impacted absolute bioavailability or clearance of midazolam short term. Long term, absolute bioavailability was similarly decreased in both groups despite different weight loss, suggesting that the recovered CYP3A‐activity is not only dependent on weight‐loss through RYGB.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

The current literature indicates an inverse relationship between body mass index (BMI) and CYP3A‐activity, and that systemic clearance of the CYP3A‐probe midazolam increases after Roux‐en‐Y gastric bypass (RYGB). However, the knowledge regarding changes in drug disposition following weight loss in general, and bariatric surgery in particular, is sparse and inconclusive, making drug dosing challenging. In addition, it remains uncertain whether pharmacokinetic changes following bariatric surgery are attributed to the gastrointestinal alterations per se and/or the subsequent weight loss.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Do body weight, weight loss, and RYGB impact CYP3A‐activity in vivo?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study shows that neither short‐term weight loss induced by RYGB or very‐low‐energy‐diet, nor RYGB per se, impact absolute bioavailability or systemic clearance of midazolam.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Our results suggests that dose adjustments of CYP3A substrate drugs, 30–50% of all drugs on the market, may not be necessary following nonsurgical and surgical weight loss neither in a short‐ nor long‐term perspective.     

Pharmacokinetics,bioavailability, and bioequivalence of lower‐sodium oxybate in healthy participants in two open‐label,randomized, crossover studies

American Academy of Sleep Medicine practice parameters designate sodium oxybate (SXB) as a standard of care for cataplexy, excessive daytime sleepiness (EDS), and disrupted night‐time sleep in narcolepsy. Recently, a lower‐sodium oxybate (LXB) with 92% less sodium than SXB was approved in the United States for the treatment of cataplexy or EDS in patients 7 years of age and older with narcolepsy. Two phase I, open‐label, randomized, single‐dose crossover pharmacokinetic studies in healthy adults were conducted. Single 4.5‐g oral doses of LXB and SXB were administered in a fasted or fed state. In the fasted state at equivalent oxybate doses, LXB, compared with SXB, had a lower maximum plasma concentration (C_max; study 1 [total aqueous volume, 240 ml]: 101.8 vs. 135.7 µg/ml; study 2 [60 ml]: 94.6 vs. 123.0 μg/ml), delayed time to C_max (T_max; study 1: 0.75 vs. 0.5 h; study 2: 1.0 vs. 0.5 h), but similar area under the curve (AUC; study 1: AUC_0‐t, 235.4 vs. 263.9 μg∙h/ml; AUC_0‐∞, 236.5 vs. 265.2 μg∙h/ml; study 2: AUC_0‐t, 241.5 vs. 254.7 μg∙h/ml; AUC_0‐∞, 243.1 vs. 256.3 μg∙h/ml). Bioequivalence criteria were met for AUC but not C_max (both studies). C_max and AUC were lower under fed than fasted conditions (LXB and SXB); differences between fed versus fasted were smaller for LXB than SXB. These pharmacokinetic differences between LXB and SXB are likely due to the lower sodium content in LXB. Pooled analyses demonstrated that a higher C_max is associated with a higher incidence of nausea and vomiting.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Sodium oxybate (SXB) and lower‐sodium oxybate (LXB) are approved in the United States for the treatment of cataplexy or excessive daytime sleepiness in patients greater than or equal to 7 years of age with narcolepsy. The pharmacokinetics (PK) of SXB includes a negative food effect (reduced maximum plasma concentration [C_max] and area under the curve [AUC]) and greater than dose‐proportional increase in exposure.

• WHAT QUESTION DID THIS STUDY ADDRESS?

What are the relative bioavailability and bioequivalence of LXB and SXB in the fasted state, and how is the PK of LXB affected by food?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

At equivalent oxybate doses, in the fasted state, LXB had a lower C_max, delayed time to C_max, and similar AUC versus SXB (bioequivalence criteria met for AUC). C_max and AUC were lower under fed conditions (LXB and SXB); reduction in C_max with food was less for LXB compared with SXB. Lower oxybate C_max was associated with lower incidence of nausea and vomiting.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

PK differences between LXB and SXB may stem from reduced sodium. LXB represents a novel oxybate treatment for narcolepsy.