A Bioequivalence Comparison Between the Once-Daily Extended-Release Tablet and the Twice-Daily Tablet Formulations of Deutetrabenazine at Steady State.

Deutetrabenazine is approved for the treatment of tardive dyskinesia and chorea associated with Huntington's disease. This study compared the exposure between the once-daily (test) and twice-daily (reference) formulations of deutetrabenazine under fed conditions. Using a randomized crossover design, healthy adults (n = 262) received the 24 mg of the test formulation once daily and 12 mg of the reference formulation twice daily, each for 7 days. Plasma concentrations were collected on Days 4-6 before dose intake, and frequently for pharmacokinetic evaluation on Days 6 and 7 for determination of deutetrabenazine and active metabolites, deuterated α-dihydrotetrabenazine (α-HTBZ) and ß-dihydrotetrabenazine (ß-HTBZ). Geometric mean ratios (GMRs, test/reference) were computed for all analytes, and bioequivalence was tested for area under the plasma concentration-time curve over 24 hours at steady state (AUC0-24 h,ss ) and for maximum plasma concentrations at steady state (Cmax,ss ). The GMRs for AUC0-24 h,ss were 115% for deutetrabenazine and 95% for deuterated total (α+ß)-HTBZ; and the GMR for Cmax,ss for deutetrabenazine was 95%. Relative bioavailability was assessed for Cmax,ss of the active metabolites; the GMR was 78% for total (α+ß)-HTBZ. At steady state, deutetrabenazine administered as the once-daily formulation was bioequivalent to the twice-daily formulation for both AUC and Cmax, and the active metabolites were bioequivalent with regard to AUC0-24 h,ss .

Evaluation of Deutetrabenazine's Potential to Delay Cardiac Repolarization Using Concentration-QTc Analysis.

Deutetrabenazine (Austedo) is indicated in adults for chorea associated with Huntington disease and tardive dyskinesia. Escalating deutetrabenazine doses were administered to healthy volunteers who were cytochrome P450 2D6 extensive/intermediate metabolizers (EMs) or poor metabolizers (PMs) to determine pharmacokinetic exposure of parent drug and active metabolites (α-dihydrotetrabenazine [α-HTBZ] and ß-dihydrotetrabenazine [ß-HTBZ]), and collect corresponding electrocardiograms (ECGs) for evaluation of the cardiodynamic effect using concentration-QTc (C-QTc) modeling. Participants (12 EMs, 24 PMs) received placebo or single doses of deutetrabenazine (24, 48, and 72 mg) to achieve plasma concentrations exceeding therapeutic range in both cohorts. Pharmacokinetic samples were obtained over 72 hours after dosing and were time matched with 12-lead ECGs extracted from continuous ECG recordings. C-QTc analysis, using linear mixed-effects modeling and model selection procedure, characterized the relationship between plasma concentrations of deutetrabenazine, deuterated α-HTBZ and ß-HTBZ, and the change from baseline in QT interval corrected using Fridericia's formula. Deutetrabenazine exhibited linear kinetics, and a C-QTc model with deuterated α-HTBZ and ß-HTBZ was selected to best describe the C-QTc relationship in pooled EM and PM data. This model predicted a placebo-corrected Fridericia corrected QT interval prolongation higher than 10 milliseconds can be excluded at concentrations associated with the maximum recommended doses in both populations. Adverse events increased with higher exposure as reflected by the higher event number in the PM cohort receiving 48 and 72 mg doses. No subject discontinued due to cardiac-related adverse events and no clinically relevant ECG findings were reported. Thus, this study found that deutetrabenazine does not have a clinically relevant effect on QT prolongation at maximum recommended doses in either cytochrome P450 2D6 EMs or PMs.

Dose selection for fremanezumab (AJOVY) phase 3 pediatric migraine studies using pharmacokinetic data from a pediatric phase 1 study and a population pharmacokinetic modeling and simulation approach.

BACKGROUND: Potential fremanezumab doses for pediatric patients were evaluated using pharmacokinetic modeling and simulation. An open-label phase 1 pharmacokinetic and safety study was conducted in pediatric patients with migraine. This study's results together with refinement of the adult population pharmacokinetic model were used to determine fremanezumab dose recommendations for phase 3 pediatric studies. METHODS: Initial application of the adult model suggested that a 75 mg dose in pediatric patients would match exposures determined safe and efficacious in adults; thus, in the phase 1 study, 15 patients, aged 6-11 years and weighing 17-45 kg received a single subcutaneous 75 mg fremanezumab dose. The sparse pharmacokinetic data collected were used to refine the adult model and simulate concentration-time profiles for monthly subcutaneous doses (60 to 225 mg) in a virtual pediatric population. RESULTS: In the phase 1 pediatric study, the safety profile was similar to that of adults. A two-compartment model with first-order absorption and elimination and body weight effects on clearance and central volume was found to adequately describe the pediatric pharmacokinetic data. CONCLUSIONS: Using exposure matching to the effective adult fremanezumab dose (225 mg subcutaneous monthly), modeling and simulations predict recommended dose of 120 mg in pediatric patients weighing < 45 kg.Registration: The phase 1 study of this report is registered at EudraCT with the identifier 2018-000734-35.

A Pharmacokinetic Bioequivalence Study of Fremanezumab Administered Subcutaneously Using an Autoinjector and a Prefilled Syringe.

Fremanezumab (AJOVY; Teva Pharmaceutical Industries Ltd, Netanya, Israel), approved for the preventive treatment of migraine, is available as a subcutaneous injection either once a month or once every 3 months using an autoinjector or a prefilled syringe. The present study evaluated the pharmacokinetic (PK) bioequivalence of a single subcutaneous injection of fremanezumab 225 mg administered using an autoinjector compared to a prefilled syringe in healthy volunteers. Blood samples for PK and antidrug antibodies were collected before and after dosing. Safety and tolerability assessments included physical examinations, adverse event reporting, laboratory evaluations, and immunogenicity. Following single-dose administration, the mean concentration-time profiles for the 2 treatment groups (autoinjector, n = 106; and prefilled syringe, n = 110) were similar. The point estimates for the back-transformed ratio (autoinjector/prefilled syringe) of geometric least squares means of maximum plasma concentration, area under the plasma concentration-time curve from time 0 to the time of the last measurable drug concentration, and area under the plasma concentration-time curve from time 0 extrapolated to infinity were 1.03, 1.04, and 1.05, respectively, with the 90% confidence intervals entirely contained within bioequivalence margins of 0.8 to 1.25. For both groups, median time to maximum observed concentration was 5 days and mean terminal elimination half-life was approximately 29 days. Treatment-related adverse events were reported by 39 (36%) subjects in the autoinjector group and 26 (24%) in the prefilled syringe group, and the majority were nonserious injection site reactions. The incidence of treatment-emergent antidrug antibody response was low and evenly distributed between the autoinjector (n = 3; 3%) and prefilled syringe (n = 4; 4%) groups. These results indicate that the fremanezumab autoinjector presentation provides an easy-to-use bioequivalent PK profile with a similar safety and tolerability profile to that of the prefilled syringe.

Pharmacokinetics of Deutetrabenazine and Tetrabenazine: Dose Proportionality and Food Effect.

Deutetrabenazine (Austedo, Teva), an approved treatment of chorea in Huntington's disease and tardive dyskinesia in adult patients, is a rationally designed deuterated form of tetrabenazine. Two studies assessed the pharmacokinetics and safety of deutetrabenazine compared with tetrabenazine, and the effects of food on absorption of the deuterated active metabolites, α-dihydrotetrabenazine (α-HTBZ) and ß-dihydrotetrabenazine (ß-HTBZ). One study was an open-label 2-part study in healthy volunteers; the first part included a crossover single dose of two 15 mg candidate deutetrabenazine formulations in fed and fasted states compared with tetrabenazine 25 mg in the fasted state, and the second part included single and repeated dosing of the commercial formulation of deutetrabenazine (7.5, 15, and 22.5 mg) compared with tetrabenazine 25 mg. The second study was an open-label 5-way crossover study in healthy volunteers (n = 32) to evaluate relative bioavailability of 4 dose levels of the commercial formulation of deutetrabenazine (6, 12, 18, and 24 mg) with a standard meal and 18 mg with a high-fat meal. Both studies confirmed longer half-lives for active metabolites and lower peak-to-trough fluctuations for the sum of the metabolites (total [α+ß]-HTBZ) following deutetrabenazine compared with tetrabenazine (3- to 4-fold and 11-fold, respectively) in steady-state conditions. Deutetrabenazine doses estimated to provide total (α+ß)-HTBZ exposure comparable to tetrabenazine 25 mg were 11.4-13.2 mg. Food had no effect on exposure to total (α+ß)-HTBZ, as measured by AUC. Although the total (α+ß)-HTBZ Cmax of deutetrabenazine was increased by ≈50% in the presence of food, it remained lower than that of tetrabenazine.

Population Pharmacokinetic and Pharmacokinetic/Pharmacodynamic Modeling of Weight-Based Intravenous Reslizumab Dosing.

Reslizumab 3.0 mg/kg has demonstrated efficacy in clinical studies of patients with eosinophilic asthma and a history of exacerbations. A population pharmacokinetic (PK) model was developed to determine whether 3.0 mg/kg weight-based dosing is appropriate to obtain consistent reslizumab exposures in all patients. PK data in healthy volunteers and patients ≥12 years with moderate to severe asthma, eosinophilic asthma, or nasal polyposis were analyzed from 4 phase 1, 2 phase 2, and 2 phase 3 studies of intravenous (IV) reslizumab (N = 804). Covariates evaluated included age, race, sex, baseline weight, renal and liver function, concomitant medications, and antidrug antibody status. Exposure-response models were developed to characterize key efficacy (blood eosinophil levels, forced expiratory volume in 1 second [FEV1 ], Asthma Control Questionnaire [ACQ-7] scores), and safety end points (muscle disorder adverse events [AEs]). Vial-based dosing was evaluated as an alternative to weight-based dosing. IV reslizumab PK was accurately described by a 2-compartment PK model with 0-order input and first-order elimination. Body weight was the only covariate that significantly influenced PK parameters. However, with weight-based dosing, comparable steady-state exposures were observed across high and low body weights. Greater eosinophil lowering and longer response duration were observed with increasing dose; exposure-related effects on FEV1 and ACQ-7 were also seen, demonstrating the clinical importance of a dosing regimen to optimize reslizumab exposure. The probability of a muscle disorder AE appeared to increase with increasing exposure. Steady-state exposure measures were similar for both dosing regimens, showing vial-based dosing as an alternative method of achieving the benefits of weight-based dosing.

Pharmacokinetic and Metabolic Profile of Deutetrabenazine (TEV-50717) Compared With Tetrabenazine in Healthy Volunteers.

Deutetrabenazine (Austedo, Teva Pharmaceuticals) is a deuterated form of tetrabenazine. It is the first deuterated drug to receive US regulatory approval and is approved for treatment of chorea in Huntington's disease and tardive dyskinesia. Two oral single dose studies comparing deutetrabenazine (25 mg) with tetrabenazine (25 mg) in healthy volunteers evaluated the impact of deuteration on pharmacokinetics of the active metabolites, alpha-dihydrotetrabenazine (α-HTBZ) and beta-dihydrotetrabenazine (ß-HTBZ), metabolite profile, safety, and tolerability. In the two-way, cross-over study, the mean elimination half-life of deuterated total (α + ß)-HTBZ was doubled compared with nondeuterated total (α + ß)-HTBZ, with a twofold increase in overall mean exposure (area under the concentration-time curve from zero to infinity (AUC0-inf )) and a marginal increase in mean peak plasma concentration (Cmax ). In the mass balance and metabolite profiling study, there were no novel plasma or urinary metabolites of [14 C]-deutetrabenazine relative to [14 C]-tetrabenazine. Specific deuteration in deutetrabenazine resulted in a superior pharmacokinetic profile and an increased ratio of active-to-inactive metabolites, attributes considered to provide significant benefits to patients.

Pharmacokinetic and Pharmacodynamic Correlations From 2 Studies Evaluating Abuse Potential of Hydrocodone Extended-Release Tablets.

Pharmacokinetic (PK)/pharmacodynamic (PD) correlations were explored in 2 human abuse potential studies of orally and intranasally administered hydrocodone extended-release (ER) 45 mg in healthy, nondependent opioid users. In a crossover study design, subjects received intact hydrocodone ER, finely milled hydrocodone ER, and hydrocodone powder in solution in the oral study and finely milled hydrocodone ER, hydrocodone powder, and finely milled Zohydro® ER in the intranasal study. Spearman ρ2 and Pearson r2 values were calculated for PD (maximum effect [Emax ] for "at the moment" Drug Liking, Overall Drug Liking, and Take Drug Again visual analog scales [VAS]) vs PK (partial area under the concentration-time curve [AUC], maximum drug concentration [Cmax ], time to Cmax [Tmax ], and abuse quotient [PK AQ; Cmax /Tmax ]) for all treatments. In the oral study, correlations were strongest between Emax of "at the moment" Drug Liking and PK parameters (Cmax [ρ2  = 0.4446], PK AQ [ρ2  = 0.5179], Tmax [ρ2  = 0.5093], and early systemic exposure [ρ2  = 0.4782]). For Overall Drug Liking and Take Drug Again VAS, ρ2 values for correlations with PK parameters ranged from 0.2620 to 0.3637. In the intranasal study, no clear correlations between PK and PD parameters were apparent.

Pharmacokinetics and safety of single and multiple doses of rasagiline in healthy Japanese and caucasian subjects.

As of March 2018, rasagiline is approved for the treatment of Parkinson disease in 55 countries including Japan. The present study evaluated the pharmacokinetics (PK) and safety of rasagiline in healthy Japanese and Caucasian subjects following single and multiple administrations of three rasagiline doses. In this double-blind, placebo-controlled study, 64 healthy subjects (32 Japanese and 32 Caucasian) received either rasagiline (0.5, 1.0, or 2.0 mg) or placebo for 10 days with PK sampling for single-dose administration on day 1 and for multiple administration on day 10. Regardless of administration schedule, rasagiline plasma concentrations and dose-related increases in exposure parameters were similar between Japanese and Caucasians. Rasagiline accumulation (2-fold for 0.5 mg and 3-fold for 1.0 mg and 2.0 mg doses) following multiple administration was similar across the ethnic groups. Geometric mean ratios (GMR) comparing Japanese to Caucasians for AUC0-24 , Cmax and AUCinf following single administration were 1.38, 1.17 and 1.38 for 0.5 mg; 1.22, 1.20 and 1.22 at 1.0 mg; and 1.02, 1.00 and 1.02 at for 2.0 mg. GMR for AUCtau and Cmax,ss following multiple administration were 1.43 and 1.06 at 0.5 mg, 1.06 and 1.00 at 1.0 mg, and 1.09 and 1.07 at 2.0 mg. Safety measures were unremarkable and similar between Caucasian and Japanese subjects. Comparable systemic exposure and safety parameters were demonstrated for rasagiline administered to healthy Japanese and Caucasian subjects.

Evaluation of the Relative Intranasal Abuse Potential of a Hydrocodone Extended-Release Tablet Formulated with Abuse-Deterrence Technology in Nondependent, Recreational Opioid Users.

Objective: To assess the intranasal abuse potential of hydrocodone extended-release (ER) tablets developed with CIMA Abuse-Deterrence Technology compared with hydrocodone powder and hydrocodone bitartrate ER capsules (Zohydro ER, original formulation [HYD-OF]). Design: Single-dose, randomized, double-blind, quadruple-dummy, active- and placebo-controlled, crossover study. Setting: One US site. Subjects: Healthy, adult, nondependent, recreational opioid users. Methods: Subjects able to tolerate intranasal hydrocodone and discriminate hydrocodone from placebo were eligible for study enrollment. Eligible participants randomly received intranasal hydrocodone ER, intranasal hydrocodone powder, intranasal HYD-OF, intact oral hydrocodone ER, and placebo. Coprimary pharmacodynamic end points were a maximum effect on "at the moment" Drug Liking visual analog scale and Overall Drug Liking visual analog scale. Pharmacokinetics and safety were assessed. Results: Mean maximum effect for "at the moment" Drug Liking was significantly (P < 0.01) lower for intranasal hydrocodone ER (72.8) compared with hydrocodone powder (80.2) and HYD-OF (83.2). Similar results were observed for Overall Drug Liking maximum effect (68.5 vs 77.1 and 79.8, respectively; P < 0.01). Secondary end points, including balance of effects and positive, sedative, and other effects, were consistent with these results. Intranasal treatments showed significantly greater effects vs placebo, while intact oral hydrocodone ER was similar to placebo. For each treatment, plasma concentration-time profiles paralleled "at the moment" Drug Liking over time. Incidences of adverse events for intranasal treatments were 52% for hydrocodone ER, 53% for hydrocodone powder, and 61% for HYD-OF. Conclusions: The statistically significant differences between hydrocodone ER vs hydrocodone powder and HYD-OF for the primary drug liking end points indicate a lower intranasal abuse potential with hydrocodone ER in healthy, nondependent, recreational opioid users.

Bioequivalence of cyclobenzaprine hydrochloride extended-release capsule taken intact or sprinkled over applesauce
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OBJECTIVE: Difficulty swallowing pills can compromise pain control in painful musculoskeletal disorders. This open-label, 2-period crossover study assessed pharmacokinetics and safety of cyclobenzaprine extended-release (CER) 30-mg capsule contents sprinkled over applesauce compared with intact capsules in healthy subjects. MATERIALS AND METHODS: 32 subjects were randomized to treatment sequences AB or BA (A = single CER intact capsule; B = single CER capsule contents sprinkled over applesauce (15 mL)). Treatments were separated by a ≥ 14-day washout. Pharmacokinetic assessments included maximum observed plasma drug concentration (Cmax), time to Cmax (tmax), time to first quantifiable plasma drug concentration (tlag), and area under the plasma drug concentration-vs.-time curve from time 0 to the last measurable drug concentration (AUC0-t) and extrapolated to infinity (AUC0-∞). Bioequivalence was established if the 90% confidence intervals (CIs) of the geometric least squares (LS) means ratios of B:A of Cmax, AUC0-t, and AUC0-∞ were 80 - 125%. Safety was also assessed. RESULTS: Mean plasma drug concentration-vs.-time profiles were similar for CER intact and sprinkled over applesauce. The 90% CIs of LS means ratios indicated bioequivalence: Cmax 91.96 - 100.76%, AUC0-t 96.18 - 103.50%, and AUC0-∞ 95.70 - 103.07%. Median tmax was not significantly different (p > 0.05), and median tlag was the same (1 hour). All adverse effects were mild and resolved during the study. No clinically meaningful changes were noted for clinical laboratory values. CONCLUSION: CER capsules intact and sprinkled over applesauce are bioequivalent. Sprinkling CER capsule contents is not expected to affect efficacy or safety and can, therefore, be an option for patients with musculoskeletal pain and difficulty swallowing capsules.
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Effect of Food on the Pharmacokinetics of Single- and Multiple-Dose Hydrocodone Extended Release in Healthy Subjects.

BACKGROUND AND OBJECTIVES: Food intake can alter the pharmacokinetics of certain medications, including changes in their oral bioavailability, which is of particular concern for extended-release (ER) opioids because of the high drug loads. Two randomized, open-label studies assessed the effect of food on the pharmacokinetics of single and multiple doses of hydrocodone ER formulated with CIMA® Abuse-Deterrence Technology. METHODS: Healthy subjects in fed and fasted states received single 90-mg doses of hydrocodone ER (Studies 1 and 2) or multiple doses of hydrocodone ER (45 mg twice daily on days 2-3, 60 mg twice daily on days 4-5, 90 mg twice daily on days 6-10, and 90 mg once in the morning on day 11) (Study 2). Naltrexone was administered to minimize opioid-related adverse events. Pharmacokinetic parameters included maximum hydrocodone plasma concentration (C max) and area under the concentration-versus-time curve from time 0 to infinity (AUC0-∞) in Study 1 (day 1) and for one dosing interval at steady state (AUCτ,ss) in Study 2 (day 11). Before conducting the multiple-dose study, single-dose data were fitted with a population pharmacokinetic methodology. RESULTS: In total, 40 subjects were randomized to Study 1 and 43 subjects were randomized to Study 2. While overall exposure (AUC0-∞) was relatively similar (least squares mean ratio [90% CI]: 1.11 [1.06-1.16]), results indicated that the single-dose C max was 40% higher under fed versus fasted conditions (least squares mean ratio [90% CI]: 1.40 [1.31-1.51]; Study 1). Modeling of single-dose data predicted that the effect of food would be much less at steady state [predicted fed:fasted C max at steady state (C max,ss) and AUCτ,ss ratios of 1.18 and 1.09, respectively]. The multiple-dose study results validated these predicted ratios and indicated that the steady-state 90% CIs were within 0.80-1.25 for the fed:fasted C max,ss (1.14 [1.07-1.21]) and AUCτ,ss (1.11 [1.04-1.17]) parameters, indicating that clinically meaningful food effects at steady state are not expected. CONCLUSION: No evidence of an effect of food was found on the pharmacokinetics of hydrocodone ER after multiple days of twice-daily dosing.

Pharmacokinetics and Safety of Single-Dose Inhaled Loxapine in Children and Adolescents.

This multisite open-label study sought to characterize the pharmacokinetics and safety of a single dose of inhaled loxapine in children and adolescents. Loxapine powder for oral inhalation was administered via a single-use handheld drug device to children and adolescents (aged 10-17 years) with any condition warranting chronic antipsychotic use. Patients were dosed according to body weight and cohort (<50 kg [n = 15], 2.5 or 5 mg; ≥50 kg [n = 15], 5 or 10 mg); the first 6 patients (cohort 1) enrolled in each weight group received the lower dose. Patients were enrolled in the higher-dose group (cohort 2) after an interim pharmacokinetic and safety analysis of data from cohort 1. Blood samples were collected for 48 hours after dosing to determine the pharmacokinetic profile of loxapine and its metabolites. Safety was assessed using adverse event (AE), laboratory value, physical/neurologic examination, vital sign, electrocardiogram, suicidality, and extrapyramidal symptom assessment. Thirty patients were enrolled and evaluable for pharmacokinetics. Loxapine plasma concentrations peaked by 2 to 5 minutes in most patients; systemic exposure increased with dose in both weight subgroups. Loxapine terminal elimination half-life was ∼13 to 17 hours. The most common AEs were sedation and dysgeusia. Sedation was severe in 1 patient in the <50-kg group (2.5-mg dose) and 1 patient in the ≥50-kg group (5-mg dose). No AEs indicative of bronchospasm or other serious AEs were reported. Inhaled loxapine was rapidly absorbed and generally well tolerated in pediatric patients; no new safety signals were observed.

Metoprolol-pridopidine drug-drug interaction and food effect assessments of pridopidine, a new drug for treatment of Huntington's disease.

AIMS: Pridopidine is an oral drug in clinical development for treatment of patients with Huntington's disease. This study examined the interactions of pridopidine with in vitro cytochrome P450 activity and characterized the effects of pridopidine on CYP2D6 activity in healthy volunteers using metoprolol as a probe substrate. The effect of food on pridopidine exposure was assessed. METHODS: The ability of pridopidine to inhibit and/or induce in vitro activity of drug metabolizing enzymes was examined in human liver microsomes and fresh hepatocytes. CYP2D6 inhibition potency and reversibility was assessed using dextromethorphan. For the clinical assessment, 22 healthy subjects were given metoprolol 100 mg alone and concomitantly with steady-state pridopidine 45 mg twice daily. Food effect on a single 90 mg dose of pridopidine was evaluated in a crossover manner. Safety assessments and pharmacokinetic sampling occurred throughout the study. RESULTS: Pridopidine was found to be a metabolism dependent inhibitor of CYP2D6, the main enzyme catalysing its own metabolism. Flavin-containing monooxygenase heat inactivation of liver microsomes did not affect pridopidine metabolism-dependent inhibition of CYP2D6 and its inhibition of CYP2D6 was not reversible with addition of FeCN3 . Exposure to metoprolol was markedly increased when coadministered with pridopidine; the ratio of the geometric means (90% confidence interval) for maximum observed plasma concentration, and area under the plasma concentration-time curve from time 0 to the time of the last quantifiable concentration and extrapolated to infinity were 3.5 (2.9, 4.22), 6.64 (5.27, 8.38) and 6.55 (5.18, 8.28), respectively. Systemic exposure to pridopidine was unaffected by food conditions. CONCLUSIONS: As pridopidine is a metabolism-dependent inhibitor of CYP2D6, systemic levels of drugs metabolized by CYP2D6 may increase with chronic coadministration of pridopidine. Pridopidine can be administered without regard to food.

A population pharmacokinetic meta-analysis of custirsen, an antisense oligonucleotide, in oncology patients and healthy subjects.

AIMS: Custirsen (OGX-011/TV-1011), a second-generation antisense oligonucleotide that reduces clusterin production, is under investigation with chemotherapy in prostate and lung cancer. This meta-analysis evaluated the population pharmacokinetics (PK) of custirsen in cancer patients and healthy subjects. METHODS: The population PK analysis used custirsen plasma concentrations from five Phase 1 studies, one Phase 1/2 study, and one Phase 3 study in two stages. Cancer patients received multiple doses of custirsen (40-640 mg intravenously over 120 min) with chemotherapy; healthy subjects received single or multiple doses (320-640 mg). An interim population PK model was developed using a nonlinear mixed-effect approach incorporating data from four Phase 1 or 1/2 studies, followed by model refinement and inclusion of two Phase 1 and one Phase 3 studies. RESULTS: The final model was developed with 5588 concentrations from 631 subjects with doses of 160-640 mg. Custirsen PK was adequately described by a three-compartment model with first-order elimination. For a representative 66-year-old individual with body weight 82 kg and serum creatinine level 0.933 mg dl-1 , the estimated typical (95% CI) parameter values were clearance (CL) = 2.36 (2.30-2.42) l h-1 , central volume of distribution (V1 ) = 6.08 (5.93-6.23) l, peripheral volume of distribution (V2 ) = 1.13 (1.01-1.25) l, volume of the second peripheral compartment (V3 ) = 15.8 (14.6-17.0) l, inter-compartmental clearance Q2 = 0.0755 (0.0689-0.0821) l h-1 , and Q3 = 0.0573 (0.0532-0.0614) l h-1 . Age, weight and serum creatinine were predictors of CL; age was a predictor of Q3 . CONCLUSION: A population PK model for custirsen was successfully developed in cancer patients and healthy subjects, including covariates contributing to variability in custirsen PK.

Clinical Trial Simulations and Pharmacometric Analysis in Pediatrics: Application to Inhaled Loxapine in Children and Adolescents.

BACKGROUND AND OBJECTIVES: Loxapine for inhalation is a drug-device combination product approved in adults for the acute treatment of agitation associated with schizophrenia or bipolar I disorder. The primary objective of this study was to develop a clinical trial protocol to support a phase I pharmacokinetic study in children aged 10 years and older. In addition, this report details the results of the clinical study in relation to the predicted likelihood of achieving the target exposure associated with therapeutic effect in adults. METHODS: A nonlinear mixed-effects population pharmacokinetic model was developed using adult data and was adjusted for the targeted pediatric age groups by applying allometric scaling to account for body size effects. Based on this pediatric model, age-appropriate regimens to achieve loxapine exposures similar to the ones associated with therapeutic effect in the adult studies were identified via trial simulation. D-optimal design and power analysis were conducted to identify optimal pharmacokinetic sampling times and sample size, respectively. RESULTS: The developed clinical trial design formed the basis of a phase I study to assess the safety and pharmacokinetics of loxapine for inhalation in children aged 10 years and older (ClinicalTrials.gov ID: NCT02184767). CONCLUSION: The results of the study indicated that overall loxapine exposures were consistent with what had been predicted by the trial simulations. The presented approach illustrates how modeling and simulation can assist in the design of informative clinical trials to identify safe and effective doses and dose ranges in children and adolescents.

Is it possible to achieve bio-equivalence between an oral solid immediate-release and an analogue enteric-coated formulation?

OBJECTIVES: While bioequivalence between enteric-coated and immediate-release formulations can be achieved in terms of AUC, gastric emptying of enteric-coated dosage forms is a stochastic event, usually leading to lower Cmax values than those observed with the corresponding immediate release. This article examines challenges of developing enteric-coated dosage forms which are bioequivalent to the corresponding immediate-release formulations in terms of both AUC and Cmax using rasagiline as a model compound. METHODS: In vitro drug release profiles of enteric-coated formulations were obtained and compared to those of the immediate-release formulation by dissolution testing. Pharmacokinetics was evaluated in bioequivalence studies in healthy human volunteers after single oral administration of enteric-coated and immediate-release formulations. KEY FINDINGS: The initial enteric-coated pellet formulation prototype was equivalent in terms of AUC, but differed in Cmax ; a second formulation prototype, consisting of a single-unit core and enteric-coating film, proved to be bioequivalent to immediate-release rasagiline tablets in terms of AUC and Cmax . In vitro, it released rasagiline rapidly at a pH of 6.8. CONCLUSIONS: Despite differences in gastric emptying between disintegrating immediate-release and enteric-coated solid dosage forms, bioequivalence in pharmacokinetic studies was achieved.

Pharmacokinetics and excretion of (14)C-omacetaxine in patients with advanced solid tumors.

Background Omacetaxine mepesuccinate is indicated in adults with chronic myeloid leukemia resistant and/or intolerant to ≥ 2 tyrosine kinase inhibitor treatments. This phase I study assessed the disposition, elimination, and safety of (14)C-omacetaxine in patients with solid tumors. Methods The study comprised a 7-days pharmacokinetic assessment followed by a treatment period of ≤ six 28-days cycles. A single subcutaneous dose of 1.25 mg/m(2) (14)C-omacetaxine was administered to six patients. Blood, urine, and feces were collected through 168 h or until radioactivity excreted within 24 h was <1 % of the dose. Total radioactivity (TRA) was measured in all matrices and concentrations of omacetaxine, 4'-desmethylhomoharringtonine (4'-DMHHT), and cephalotaxine were measured in plasma and urine. For each treatment cycle, patients received 1.25 mg/m(2) omacetaxine twice daily for 7 days. Results Mean TRA recovered was approximately 81 % of the dose, with approximately half of the radioactivity recovered in feces and half in urine. Approximately 20 % of the dose was excreted unchanged in urine; cephalotaxine (0.4 % of dose) and 4' DMHHT (9 %) were also present. Plasma concentrations of TRA were higher than the sum of omacetaxine and known metabolites, suggesting the presence of other (14)C-omacetaxine-derived compounds. Fatigue and anemia were common, consistent with the known toxicity profile of omacetaxine. Conclusion Renal and hepatic processes contribute to the elimination of (14)C-omacetaxine-derived radioactivity in cancer patients. In addition to omacetaxine and its known metabolites, other (14)C-omacetaxine-derived materials appear to be present in plasma and urine. Omacetaxine was adequately tolerated, with no new safety signals.

Impact of dosing regimen of custirsen, an antisense oligonucleotide, on safety, tolerability and cardiac repolarization in healthy subjects.

AIMS: Custirsen (OGX-011/TV-1011), a second-generation antisense oligonucleotide (ASO) that reduces clusterin production, is under investigation with chemotherapy in patients with solid tumours. Custirsen is associated with constitutional symptoms (CS) that may interfere with clinical pharmacology investigations, such as QT interval studies. Experience with other ASOs suggests NSAID premedication may ameliorate CS, but we observed suboptimal outcomes in healthy subjects given custirsen and NSAIDs. We sought to establish a custirsen regimen for future clinical pharmacology studies in healthy subjects. METHODS: Subjects received custirsen (640 mg intravenously over 120 min) with dexamethasone premedication or increasing doses (320, 480, 640 mg over 6 days) of custirsen with dexamethasone premedication, then one full custirsen dose without premedication on day 8. Incidence/severity of adverse events (AEs) and extensive electrocardiogram readings were evaluated. Pharmacokinetic parameters were estimated. RESULTS: AEs included CS, elevated transaminases and prolonged activated partial thromboplastin time (aPTT) that were predominantly grade 1/2. Administration of increasing custirsen doses and dexamethasone premedication reduced the incidence of CS associated with full dose custirsen. Transaminase elevation showed a dose-dependent effect (0% at days 2, 4, 27% at day 6) with the highest custirsen doses. Increasing doses of custirsen may have mitigated the severity but not incidence of aPTT prolongation. Neither regimen was associated with cardiac repolarization changes in QT values or concentration-effect analyses. The custirsen pharmacokinetic profile was consistent with previous experience. CONCLUSION: Escalation of custirsen dose combined with dexamethasone premedication reduced CS associated with full dose custirsen and should be considered in future clinical pharmacology studies of custirsen.

Cardiac safety of rasagiline, a selective monoamine oxidase type B inhibitor for the treatment of Parkinson's disease: a thorough QT/QTc study.

AIMS: Rasagiline is a selective, irreversible monoamine oxidase type B inhibitor, developed for the treatment of Parkinson's disease. In compliance with current regulatory requirements, rasagiline underwent a thorough QT/QTc (TQT) study to assess its potential to prolong cardiac repolarization. The primary aim of this study was to evaluate the effects of clinical (1 mg/day) and supratherapeutic (2 mg/day and 6 mg/day) multiple oral doses of rasagiline on the baseline- and placebo-adjusted QTc interval (delta delta QTc (ddQTc)). Other electrocardiogram parameters, pharmacokinetic assessments, safety and tolerability as well as vital signs were investigated. METHODS: This was a five-arm, randomized, double-blind, placebo- and active-controlled, and parallel study in healthy subjects. Moxifloxacin (400 mg) positive control was included to demonstrate assay sensitivity. RESULTS: 247 of 250 randomized subjects completed the study. Time-matched analysis of ddQTc yielded two-sided 90% confidence intervals for all rasagiline doses below the 10 ms regulatory threshold, showing no effect on cardiac repolarization. Concentration-effect analysis demonstrated no relationships between rasagiline (and its metabolite 1-aminoindan), plasma concentrations, and ddQTc. The pharmacokinetic profile of rasagiline was consistent with previous studies. Adverse events were mild to moderate in intensity and were similar across all treatment groups. There were no clinically significant changes in heart rate and systolic blood pressure. CONCLUSION: This TQT study demonstrated a favorable cardiac safety profile of rasagiline.