Characterization of the Pharmacokinetic and Pharmacodynamic Profile of Apraglutide, a Glucagon-Like Peptide-2 Analog, in Healthy Volunteers.

Apraglutide (FE 203799) is a glucagon-like peptide-2 (GLP-2) analog under development for the treatment of intestinal failure associated with short bowel syndrome (SBS-IF) and graft-versus-host disease (GvHD). Compared with native GLP-2, apraglutide has slower absorption, reduced clearance, and higher protein binding, enabling once-weekly dosing. This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) profile of apraglutide in healthy adults. Healthy volunteers were randomized to receive 6 weekly subcutaneous administrations of 1, 5, or 10 mg apraglutide or placebo. PK and citrulline (an enterocyte mass PD marker) samples were collected at multiple time points. Kinetic parameters of apraglutide and citrulline were calculated using noncompartmental analysis; repeated PD measures were analyzed with a mixed model of covariance. A population PK/PD model was developed that also included data from a previous phase 1 study in healthy volunteers. Twenty-four subjects were randomized; 23 received all study drug administrations. Mean estimated apraglutide clearance was 16.5-20.7 l/day, and mean volume of distribution was 55.4-105.0 liters. A dose-dependent increase in citrulline plasma concentration was observed, with 5-mg and 10-mg doses inducing higher citrulline levels than 1-mg doses and placebo. PK/PD analysis showed that weekly 5-mg apraglutide induced the maximal citrulline response. Increased plasma citrulline levels were sustained for 10-17 days after the final apraglutide administration. Apraglutide displays predictable dose-dependent PK and PD profiles, with a 5-mg dose showing significant PD effects. Results suggest that apraglutide has early and enduring effects on enterocyte mass and supports the continued development of weekly subcutaneous apraglutide for SBS-IF and GvHD patient populations. SIGNIFICANCE STATEMENT: Once-weekly subcutaneous apraglutide results in dose-dependent elevations of plasma citrulline (an enterocyte mass pharmacodynamic marker) with parameters suggesting that apraglutide has lasting effects on enterocyte mass and the potential to provide therapeutic benefits. This is the first report of a model relating glucagon-like peptide-2 (GLP-2) agonism and its effects in intestinal mucosa, affording not only the ability to predict pharmacologic effects of GLP-2 analogs but also the exploration of optimal dosing regimens for this drug class across populations with different body weights.

Low Potential of Basimglurant to Be Involved in Drug-Drug Interactions: Influence of Non-Michaelis-Menten P450 Kinetics on Fraction Metabolized.

Basimglurant, a novel mGlu5-negative allosteric modulator under development for the treatment of major depressive disorder, is cleared via cytochrome P450 (P450)-mediated oxidative metabolism. Initial enzyme phenotyping studies indicated that CYP3A4/5 dominates basimglurant metabolism and highlights a risk for drug-drug interactions when it is comedicated with strong CYP3A4/5 inhibitors or inactivators; however, a clinical drug-drug interaction (DDI) study using the potent and selective CYP3A4/5 inhibitor ketoconazole resulted in an area under the curve (AUC) AUCi/AUC ratio of only 1.24. A further study using the CYP3A4 inducer carbamazepine resulted in an AUCi/AUC ratio of 0.69. More detailed in vitro enzyme phenotyping and kinetics studies showed that, at the low concentrations attained clinically, basimglurant metabolic clearance is catalyzed mainly by CYP1A2. The relative contributions of the enzymes were estimated as 70:30 CYP1A2:CYP3A4/5. Using this information, a clinical study using the CYP1A2 inhibitor fluvoxamine was performed, resulting in an AUCi/AUC ratio of 1.60, confirming the role of CYP1A2 and indicating a balanced DDI risk profile. Basimglurant metabolism kinetics show enzyme dependency: CYP1A2-mediated metabolism follows Michaelis-Menten kinetics, whereas CYP3A4 and CYP3A5 follow sigmoidal kinetics [with similar constant (KM) and S50 values]. The interplay of the different enzyme kinetics leads to changing fractional enzyme contributions to metabolism with substrate concentration, even though none of the metabolic enzymes is saturated. This example demonstrates the relevance of non-Michaelis-Menten P450 enzyme kinetics and highlights the need for a thorough understanding of metabolism enzymology to make accurate predictions for human metabolism in vivo.

A double-tracer technique to characterize absorption, distribution, metabolism and excretion (ADME) of [14C]-basimglurant and absolute bioavailability after oral administration and concomitant intravenous microdose administration of [13C6]-labeled basimglurant in humans.

1. The emerging technique of employing intravenous microdose administration of an isotope tracer concomitantly with an [14C]-labeled oral dose was used to characterize the disposition and absolute bioavailability of a novel metabotropic glutamate 5 (mGlu5) receptor antagonist under clinical development for major depressive disorder (MDD). 2. Six healthy volunteers received a single 1 mg [12C/14C]-basimglurant (2.22 MBq) oral dose and a concomitant i.v. tracer dose of 100 µg of [13C6]-basimglurant. Concentrations of [12C]-basimglurant and the stable isotope [13C6]-basimglurant were determined in plasma by a specific LC/MS-MS method. Total [14C] radioactivity was determined in whole blood, plasma, urine and feces by liquid scintillation counting. Metabolic profiling was conducted in plasma, urine, blood cell pellet and feces samples. 3. The mean absolute bioavailability after oral administration (F) of basimglurant was ∼67% (range 45.7-77.7%). The major route of [14C]-radioactivity excretion, primarily in form of metabolites, was in urine (mean recovery 73.4%), with the remainder excreted in feces (mean recovery 26.5%). The median tmax for [12C]-basimglurant after the oral administration was 0.71 h (range 0.58-1.00) and the mean terminal half-life was 77.2 ± 38.5 h. Terminal half-life for the [14C]-basimglurant was 178 h indicating presence of metabolites with a longer terminal half-life. Five metabolites were identified with M1-Glucuronide as major and the others in trace amounts. There was minimal binding of drug to RBCs. IV pharmacokinetics was characterized with a mean ± SD CL of 11.8 ± 7.4 mL/h and a Vss of 677 ± 229 L. 4. The double-tracer technique used in this study allowed to simultaneously characterize the absolute bioavailability and disposition characteristics of the new oral molecular entity in a single study.

Pharmacokinetics and Tolerability of a Single Dose of Apraglutide, a Novel, Long-Acting, Synthetic glucagon-like peptide-2 Analog With a Unique Pharmacologic Profile, in Individuals With Impaired Renal Function.

Renal impairment is a common complication in patients with short bowel syndrome with intestinal failure (SBS-IF). Glucagon-like peptide-2 analogs, such as apraglutide, have been developed as a treatment option for SBS-IF. This study assessed the potential for apraglutide overexposure in individuals with severely impaired renal function versus healthy volunteers with normal renal function. In this phase 1, open-label, multicenter, nonrandomized, parallel-group study, a single dose of apraglutide 5 mg was administered subcutaneously to individuals with severely impaired renal function (<30 mL/min/1.73 m2) and healthy volunteers with normal renal function (≥90 mL/min/1.73 m2). Primary pharmacokinetic endpoints were maximum observed concentration (Cmax) and exposure to apraglutide (area under the curve [AUC] from time 0 to infinity [AUCinf], and AUC from time 0 to the last quantifiable concentration [AUClast]). Each group comprised 8 individuals. Results show that patients with severe renal impairment do not have increased apraglutide exposure. Apraglutide achieved a lower Cmax and AUCinf in individuals with severe renal impairment versus those with normal renal function (Cmax = 36.9 vs 59.5 ng/L; AUCinf = 3100 vs 4470 h · ng/mL, respectively). The respective geometric mean ratios were 0.620 and 0.693 for Cmax and AUCinf, and the upper bound of their 90% confidence intervals were <2, indicating patients with severe renal impairment were not overexposed to apraglutide versus those with normal renal function. Adverse events were mild or moderate in severity. Apraglutide does not require dose reduction for any degree of renal impairment and could be used in a broader patient population of renally impaired patients without dose adjustment.

Pattern recognition analysis of digital ECGs: decreased QT measurement error and improved precision compared to semi-automated methods.

BACKGROUND AND PURPOSE: Machine-read QT measurements employing T-wave detection algorithms (ALG) are not accepted by regulatory agencies for the primary analysis of thorough QT (TQT) studies. Newly developed pattern recognition software (PRO) which matches ECG waveforms to user-defined templates may improve this situation. METHODS: We compared RR, QT, QTc, QT variability, T-end measurement errors, and individual QT rate correction factors and their associated coefficients of determination (R(2)) following ALG and PRO analysis. Machine-read QTc values were compared with core laboratory semi-automated (SA) values for verification. RESULTS: Compared to ALG, PRO reduced the frequency of T-end measurement errors (5.6% vs. 0.1%), reduced the intra-individual QT variability (12.6±5.9 vs. 4.9±1.1ms) and allowed the recovery of 3/58 subjects that exhibited an unacceptable (<0.9) R(2). CONCLUSIONS: PRO adjusted for ALG-based T-end measurement errors and provided an accurate and precise automated method for continuous QT analysis, thus offering an alternative to resource-intensive semi-automated analyses currently performed by ECG core laboratories.

Comparative TQT analysis with three fully-automated platforms: comparison to core laboratory semi-automated results.

BACKGROUND AND PURPOSE: Technological advances in machine-read QT measurement now enable detailed and precise cardiac repolarization assessments. This study assessed the applicability of three state-of-art ECG measurement applications to provide reliable continuous analyses from data obtained in a positive thorough QT study previously characterized with sparse semi-automated measurements performed by an ECG core laboratory. METHODS: Continuous RR, QT, QTc measurements, and individual QT/RR relationships and their associated intra- and inter-subject variability were derived in parallel with BioQT, Ponemah PRO, and WinAtrec analysis software. RESULTS: Despite slight vendor-specific differences in measurement variability and QTc, all machine-read methods demonstrated requisite assay sensitivity and yielded similar conclusions in accordance with SA analysis. CONCLUSIONS: Three commercially available ECG analytical software applications reliably detected the drug-induced QT prolonging effects and replicated the SA core-laboratory conclusions, with greatly improved temporal resolution and reduced analytical costs. With broader experience, these data suggest that current SA methodologies could be effectively replaced by fully automated ECG analysis.

Pharmacokinetics of licarbazepine in healthy volunteers: single and multiple oral doses and effect of food.

Two studies characterized single- and multiple-dose pharmacokinetics of licarbazepine immediate-release tablets and food effects on single-dose pharmacokinetics. In 1 study, 12 volunteers received 500 mg licarbazepine on day 1, 500 mg bid on days 3 to 6, and 500 mg on day 7. In the second study, 12 subjects received one 500-mg licarbazepine dose under fasted and fed conditions. After multiple dosing, geometric mean (%CV) Cmax ss, Cmin ss, and AUCtau were 77.6 micromol/L (18), 45.3 micromol/L (25), and 747 h.mol/L (19), respectively, with a tmax of 2 hours. Mean half-lives were 9.3 and 11.3 hours for single and multiple dosing, respectively. Food had no clinically significant effect on single-dose pharmacokinetics. Half-life ( approximately 10 hours) and low intersubject variability in main pharmacokinetic parameters were similar under fasted and fed conditions. Median tmax increased from 1.5 to 2.5 hours with food. Licarbazepine is well tolerated and has predictable pharmacokinetics.

Test-retest reliability of task-based and resting-state blood oxygen level dependence and cerebral blood flow measures.

Despite their wide-spread use, only limited information is available on the comparative test-retest reliability of task-based functional and resting state magnetic resonance imaging measures of blood oxygen level dependence (tb-fMRI and rs-fMRI) and cerebral blood flow (CBF) using arterial spin labeling. This information is critical to designing properly powered longitudinal studies. Here we comprehensively quantified and compared the test-retest reliability and reproducibility performance of 8 commonly applied fMRI tasks, 6 rs-fMRI metrics and CBF in 30 healthy volunteers. We find large variability in test-retest reliability performance across the different tb-fMRI paradigms and rs-fMRI metrics, ranging from poor to excellent. A larger extent of activation in tb-fMRI is linked to higher between-subject reliability of the respective task suggesting that differences in the amount of activation may be used as a first reliability estimate of novel tb-fMRI paradigms. For rs-fMRI, a good reliability of local activity estimates is paralleled by poor performance of global connectivity metrics. Evaluated CBF measures provide in general a good to excellent test-reliability matching or surpassing the best performing tb-fMRI and rs-fMRI metrics. This comprehensive effort allows for direct comparisons of test-retest reliability between the evaluated MRI domains and measures to aid the design of future tb-fMRI, rs-fMRI and CBF studies.

Clinical trial considerations on male contraception and collection of pregnancy information from female partner: update.

BACKGROUND: This is an update to our 2012 publication on clinical trial considerations on male contraception and collection of pregnancy information from female partner, after critical review of recent (draft) guidances released by the International Council for Harmonisation [ICH] the Clinical Trial Facilitation Group [CTFG] and the US Food & Drug Administration [FDA]. METHODS: Relevant aspects of the new guidance documents are discussed in the context of male contraception and pregnancy reporting from female partner in clinical trials and the approach is updated accordingly. RESULTS: Genotoxicity The concept of a threshold is introduced using acceptable daily intake/permissible daily exposure to define genotoxicity requirements, hence highly effective contraception in order to avoid conception. The duration for highly effective contraception has been extended from 74 to 90 days from the end of relevant systemic exposure. Teratogenicity Pharmacokinetic considerations to estimate safety margins have been contextualized with regard to over- and underestimation of the risk of teratogenicity transmitted by a vaginal dose. The duration of male contraception after the last dose takes into account the end of relevant systemic exposure if measured, or a default period of five half-lives after last dose for small molecules and two half-lives for immunoglobulins (mAbs). Measures to prevent exposure of the conceptus via a vaginal dose apply to reproductively competent or vasectomized men, unless measurements fail to detect the compound in seminal fluid. CONCLUSION: Critical review of new guidance documents provides a comparison across approaches and resulted in an update of our previous publication. Separate algorithms for small molecules and monoclonal antibodies are proposed to guide the recommendations for contraception for male trial participants and pregnancy reporting from female partners. No male contraception is required if the dose is below a defined threshold for genotoxic concern applicable to small molecules. For men treated with teratogenic mAbs, condom use to prevent exposure of a potentially pregnant partner is unlikely to be recommended because of the minimal female exposure anticipated following a vaginal dose. The proposed safety margins for teratogenicity may evolve with further knowledge.

QT and QTc interval with standard and supratherapeutic doses of darifenacin, a muscarinic M3 selective receptor antagonist for the treatment of overactive bladder.

Prolongation of QT interval on an electrocardiogram is a valuable predictor of a drug's ability to cause potentially fatal ventricular tachyarrhythmia (torsades de pointes). Darifenacin is a muscarinic M3 selective receptor antagonist developed for the treatment of overactive bladder, a debilitating condition that is particularly prevalent in the older population. This 7-day, randomized, parallel-group study (n=188) measured QT/QTc interval in healthy volunteers receiving once-daily darifenacin at steady-state therapeutic (15 mg) and supratherapeutic (75 mg) doses, alongside controls receiving placebo or moxifloxacin (positive control, 400 mg) once daily. There was no significant increase in QTcF interval with darifenacin treatment compared with placebo. Mean changes from baseline at pharmacokinetic Tmax versus placebo were -0.4 and -2.2 milliseconds in the darifenacin 15 mg and 75 mg groups, respectively, compared with +11.6 milliseconds in the moxifloxacin group (P<.01). This study demonstrates that darifenacin does not prolong QT/QTc interval.

Pimecrolimus identifies a common genomic anti-inflammatory profile, is clinically highly effective in psoriasis and is well tolerated.

The ascomycin macrolactam pimecrolimus is a novel inflammatory cytokine release inhibitor that so far has not been administered systemically to humans. In this phase I/II randomized double-blind, placebo-controlled, multiple rising dose proof of concept study psoriasis patients were treated with oral pimecrolimus or placebo. Gene profiling identified a common genomic profile with a downregulation of genes associated with inflammation but no changes in gene expression linked to drug-related side-effects. A steady state of pimecrolimus was reached after 5-10 d, Cmax, and area under the curve (0-24) was 54.5 ng per ml and 589.9 ng h per ml, respectively, at steady state at the highest dose. There was clear clinical efficacy in patients receiving 20 mg pimecrolimus twice daily and 30 mg twice daily with a reduction of Psoriasis Area and Severity Index by 60% and 75%, respectively. Histopatho logically and immunopathologically there was a reversion of the psoriatic phenotype towards normal. There were no notable clinical, laboratory, kidney function, or immunologic side-effects. We conclude that pimecrolimus taken orally is highly effective in a concentration-dependent manner in patients with psoriasis and on a short-term basis it is well tolerated and this is confirmed by its pharmacogenomic profile. The latter also indicates that pimecrolimus should be equally effective in other inflammatory skin diseases.

Pharmacokinetics of pimecrolimus, a novel nonsteroid anti-inflammatory drug, after single and multiple oral administration.

OBJECTIVE: To investigate the pharmacokinetics and tolerability of the new nonsteroid anti-inflammatory pimecrolimus (SDZ ASM 981, Elidel) after oral administration. DESIGN: A single-dose, randomised, double-blind, placebo-controlled, dose-rising, parallel-group study in healthy male volunteers, and a multiple-dose, randomised, double-blind, placebo-controlled, dose-rising study in patients with psoriasis. SETTING: One centre in France (single-dose study) and one centre in Austria (multiple-dose study). METHODS: The first study investigated the pharmacokinetics and tolerability of ascending single oral doses of pimecrolimus (5-60mg). The 60mg dose was repeated in the same subjects after a fat-rich breakfast. The second study investigated the pharmacokinetics, tolerability, safety and efficacy of rising oral doses administered once daily (5-20mg) or twice daily (20 and 30mg) for 28 days. Only the pharmacokinetic, safety and tolerability data of this study are presented. OUTCOME MEASURES AND RESULTS: Oral administration of pimecrolimus was well tolerated up to the highest dose (60mg). Pimecrolimus was rapidly absorbed (time to maximum blood concentration 0.7-2 hours). A high-fat meal before drug administration delayed the time to peak concentration. Blood concentrations appear to have a long-terminal half-life (30-40 hours after a single dose in fasted subjects, 50-100 hours after the final dose on day 28 in psoriasis patients). After multiple doses, steady state was attained after 6-13 days. Maximum blood concentrations (C(max)) and exposure (area under the concentration-time curve; AUC) were broadly dose proportional. At the highest dose administered in the multiple-dose study (30mg twice daily), a C(max ) of 54.7 microg/L was measured and an AUC(24) of 589.8 microg.h/L was calculated at steady state (day 13). CONCLUSION: The results support further evaluation of the therapeutic potential of oral pimecrolimus for the treatment of inflammatory diseases.

A phase I study of weekly R1507, a human monoclonal antibody insulin-like growth factor-I receptor antagonist, in patients with advanced solid tumors.

PURPOSE: A phase I study was conducted to evaluate the pharmacokinetics, pharmacodynamics, safety, and tolerability of R1507-a fully human IgG1 type monoclonal antibody directed against the human insulin-like growth factor-I receptor. EXPERIMENTAL DESIGN: Patients with advanced solid tumors were assigned to receive i.v. R1507 weekly (qW), starting with 1 mg/kg. Subsequent cohorts were dosed at 3 and then 9 mg/kg. An additional 12 patients received 9 mg/kg R1507 qW. Patients remained on the study until the development of a dose-limiting toxicity or progressive disease. RESULTS: In total, 37 patients were treated with R1507 qW. No dose-limiting toxicities were identified and the maximum tolerated dose was not reached. The pharmacokinetics of R1507 were characterized by a slow clearance and limited volume of distribution, with an estimated elimination half-life justifying weekly administration. Serum IGF-I ligand levels increased proportionally to dose during the first 72 hours in all cohorts. R1507 was well tolerated. Two patients diagnosed with Ewing's sarcoma had partial responses of 11.5 and >26 months (ongoing at time of submission); 13 patients had stable disease; and 16 had progressive disease as best response by the Response Evaluation Criteria in Solid Tumors. CONCLUSION: R1507 is well tolerated and shows antitumor activity in patients with solid neoplasms, in particular Ewing's sarcoma. The recommended dose for the weekly schedule is 9 mg/kg qW.