α-Pyrrolidinohexanophenone (α-PHP) vs. α-pyrrolidinoisohexanophenone (α-PiHP): A toxicological investigation about plasma concentrations and behavior in forensic routine cases.

New psychoactive substances (NPS), like pyrrolidinophenones, are still very present on the illegal drug market. The presented study reports on two members of this substance group, α-pyrrolidinohexanophenone (α-PHP) and α-pyrrolidinoisohexanophenone (α-PiHP), which occurred in forensic routine cases in the last 6 years. α-PHP could be detected predominantly by a validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) method in 33 authentic human plasma samples and α-PiHP in 8. α-PHP concentrations ranged from ca. 0.75 to 128 µg/L (mean: 23.2, median: 16.3) and α-PiHP concentrations from 7.33 to 118 µg/L (mean: 44.7, median: 33.7, quantified via α-PHP). Individuals were predominantly male and middle aged. As different studies have shown, some pyrrolidinophenones are able to cause aggressive behavior. Therefore, we set out to investigate the relation of α-PHP and α-PiHP plasma concentrations and the behavior of the consumers, reported by police and medical experts. Part of the subjects showed aggressive behavior, including agitation and restlessness. Lethargic and unremarkable behavior might be explained by co-consumption of other drugs, such as opiates/opioids, benzodiazepines, pregabalin or alcohol as well as by drug tolerance and subacute effects of stimulants. Multi-drug use could be detected in all cases; also stimulating substances and multiple different pyrrolidinophenones were determined. Nevertheless, users of α-PHP and α-PiHP showed a tendency to act aggressively, possibly triggered by a high selectivity for dopamine transporter inhibition. In accordance, committed offenses were often violent crimes. This might be considered in terms of toxicological assessment of criminal responsibility and driving ability.

Therapeutic Effects of Time-Limited Treatment with Brivaracetam on Posttraumatic Epilepsy after Fluid Percussion Injury in the Rat.

Mounting evidence suggests the synaptic vesicle glycoprotein 2A (SV2A) targeted by levetiracetam may contribute to epileptogenesis. Levetiracetam has shown anti-inflammatory, antioxidant, neuroprotective, and possible antiepileptogenic effects in brain injury and seizure/epilepsy models, and a phase 2 study has signaled a possible clinical antiepileptogenic effect. Brivaracetam shows greater affinity and specificity for SV2A than levetiracetam and broader preclinical antiseizure effects. Thus, we assessed the antiepileptogenic/disease-modifying potential of brivaracetam in an etiologically realistic rat posttraumatic epilepsy model optimized for efficient drug testing. Brivaracetam delivery protocols were designed to maintain clinical moderate-to-high plasma levels in young (5-week-old) male Sprague-Dawley rats for 4 weeks. Treatment protocols were rapidly screened in 4-week experiments using small groups of animals to ensure against rigorous testing of futile treatment protocols. The antiepileptogenic effects of brivaracetam treatment initiated 30 minutes, 4 hours, and 8 hours after rostral parasagittal fluid percussion injury (rpFPI) were then compared with vehicle-treated controls in a fully powered blind and randomized 16-week validation. Seizures were evaluated by video-electrocorticography using a 5-electrode epidural montage. Endpoint measures included incidence, frequency, duration, and spread of seizures. Group sizes and recording durations were supported by published power analyses. Three months after treatment ended, rats treated with brivaracetam starting at 4 hours post-FPI (the best-performing protocol) experienced a 38% decrease in overall incidence of seizures, 59% decrease in seizure frequency, 67% decrease in time spent seizing, and a 45% decrease in the proportion of spreading seizures that was independent of duration-based seizure definition. Thus, brivaracetam shows both antiepileptogenic and disease-modifying properties after rpFPI. SIGNIFICANCE STATEMENT: The rpFPI model, which likely incorporates epileptogenic mechanisms operating after human head injury, can be used to efficiently screen investigational treatment protocols and assess antiepileptogenic/disease-modifying effects. Our studies 1) support a role for SV2A in epileptogenesis, 2) suggest that brivaracetam and other drugs targeting SV2A should be considered for human clinical trials of prevention of post-traumatic epilepsy after head injury, and 3) provide data to inform the design of treatment protocols for clinical trials.

Influence of dose and antiepileptic comedication on brivaracetam serum concentrations in patients with epilepsy.

The aim of this study was to investigate the influence of concomitant antiepileptic drugs (AEDs) on brivaracetam (BRV) trough serum concentrations. A total number of 368 routinely collected blood samples from 148 inpatients from Mara Hospital (Bethel Epilepsy Center) and von Bodelschwingh Foundation Bethel were retrospectively evaluated. Generalized estimation equations (GEEs) were used for statistical analysis. GEE analyses showed that BRV trough serum concentrations were significantly lower in patients with strong enzyme-inducing AEDs (carbamazepine, phenytoin, and/or phenobarbital/primidone, -49%), but were not affected by concomitant intake of oxcarbazepine or eslicarbazepine. Age and gender did not have a significant effect. An alternative GEE model analyzing the BRV level-to-dose ratios yielded comparable results. Our results from routine therapeutic drug monitoring data indicate that the effect of enzyme-inducing AEDs on BRV serum concentrations is stronger than the 20%-30% reduction in BRV exposure previously reported in pharmacokinetics studies. Further research is necessary to evaluate these differences and to elucidate possible clinical consequences.

Development and Validation of an UHPLC-MS/MS Assay for the Therapeutic Monitoring of Brivaracetam Plasma Concentrations in Patients with Epilepsy.

BACKGROUND: Brivaracetam is an antiepileptic drug used as an add-on therapy for partial-onset seizures in subjects aged 4 years and older. Owing to potential drug interactions and intersubject variability in plasma concentrations, therapeutic monitoring for brivaracetam may be useful. The aim of this study was to develop a simplified method for measuring brivaracetam plasma concentrations applicable to therapeutic drug monitoring in epilepsy. METHODS: An ultra high-pressure liquid chromatography-tandem mass spectrometry method was developed and validated according to current guidelines for bioanalytical methods. Sample preparation (100 µL) involved only a simple precipitation step by acetonitrile. Brivaracetam-d7 was used as internal standard. The chromatographic analysis was performed by a Synergi Fusion column using 0.1% formic acid in water/acetonitrile as a binary gradient mobile phase, at a flow rate of 0.3 mL/min. Both brivaracetam and the internal standard eluted at 1.01 minutes. This method was applied to measure trough and 1-hour postmorning dose brivaracetam plasma concentrations of 11 patients with epilepsy. RESULTS: The method was validated over a concentration range of 0.10-10 mcg/mL. The mean recovery was 95%. Both intra- and inter-assay imprecision and inaccuracy were <15% for all quality control samples. The lower limit of quantitation and detection was 0.10 and 0.05 mcg/mL, respectively. No interferences or carry-over was observed. Median (25%-75% quartiles) trough and 1-hour postdosing brivaracetam plasma concentrations were 0.61 mcg/mL (0.47-0.83 mcg/mL) and 1.55 mcg/mL (1.24-2.12 mcg/mL), respectively, at a median dose of 80 mg/d (50-150 mg/d). Large, up to 8-fold, intrasubject fluctuations of brivaracetam concentrations between trough and 1-hour postdosing were observed. CONCLUSIONS: The present assay is faster and simpler than previously published analytical reports for brivaracetam in human plasma and is suitable for therapeutic drug monitoring.

Effects of cannabidiol on brivaracetam plasma levels.

The use of cannabidiol (CBD) for treatment of pharmacoresistant epilepsies is increasing. CBD is metabolized via UDP-glucuronosyltransferase (UGT) and cytochrome 450 (CYP) enzymes, but information on interactions with common anticonvulsive drugs is incomplete. We report a case series of five patients receiving adjunctive treatment with CBD who showed increases in brivaracetam (BRV) levels by 95% to 280%. Only two patients reported mild adverse events, leading to a reduction of BRV in one patient. One possible mechanism contributing at least partially to increasing BRV level is the inhibition of CYP2C19 by cannabidiol. Further pharmacokinetic studies are required to understand other possible mechanisms of brivaracetam-cannabidiol interaction.

Serum Metabolomics and Incidence of Atrial Fibrillation (from the Atherosclerosis Risk in Communities Study).

We have previously identified associations of 2 circulating secondary bile acids (glycocholenate and glycolithocolate sulfate) with atrial fibrillation (AF) risk in 1,919 blacks in the Atherosclerosis Risk in Communities cohort. We aimed to replicate these findings in an independent sample of 2,003 white and black Atherosclerosis Risk in Communities participants, and performed a new metabolomic analysis in the combined sample of 3,922 participants, followed between 1987 and 2013. Metabolomic profiling was done in baseline serum samples using gas and liquid chromatography mass spectrometry. AF was ascertained from electrocardiograms, hospitalizations, and death certificates. We used multivariable Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) of AF by 1 standard deviation difference of metabolite levels. Over a mean follow-up of 20 years, 608 participants developed AF. Glycocholenate sulfate was associated with AF in the replication and combined samples (HR 1.10, 95% CI 1.00, 1.21 and HR 1.13, 95% CI 1.04, 1.22, respectively). Glycolithocolate sulfate was not related to AF risk in the replication sample (HR 1.02, 95% CI 0.92, 1.13). An analysis of 245 metabolites in the combined cohort identified 3 additional metabolites associated with AF after multiple-comparison correction: pseudouridine (HR 1.18, 95% CI 1.10, 1.28), uridine (HR 0.86, 95% CI 0.79, 0.93) and acisoga (HR 1.17, 95% CI 1.09, 1.26). In conclusion, we replicated a prospective association among a previously identified secondary bile acid, glycocholenate sulfate, and AF incidence, and identified new metabolites involved in nucleoside and polyamine metabolism as markers of AF risk.

A single-center, open-label positron emission tomography study to evaluate brivaracetam and levetiracetam synaptic vesicle glycoprotein 2A binding in healthy volunteers.

OBJECTIVE: Brivaracetam (BRV) and levetiracetam (LEV) are antiepileptic drugs that bind synaptic vesicle glycoprotein 2A (SV2A). In vitro and in vivo animal studies suggest faster brain penetration and SV2A occupancy (SO) after dosing with BRV than LEV. We evaluated human brain penetration and SO time course of BRV and LEV at therapeutically relevant doses using the SV2A positron emission tomography (PET) tracer 11 C-UCB-J (EP0074; NCT02602860). METHODS: Healthy volunteers were recruited into three cohorts. Cohort 1 (n = 4) was examined with PET at baseline and during displacement after intravenous BRV (100 mg) or LEV (1500 mg). Cohort 2 (n = 5) was studied during displacement and 4 hours postdose (BRV 50-200 mg or LEV 1500 mg). Cohort 3 (n = 4) was examined at baseline and steady state after 4 days of twice-daily oral dosing of BRV (50-100 mg) and 4 hours postdose of LEV (250-600 mg). Half-time of 11 C-UCB-J signal change was computed from displacement measurements. Half-saturation concentrations (IC50 ) were determined from calculated SO. RESULTS: Observed tracer displacement half-times were 18 ± 6 minutes for BRV (100 mg, n = 4), 9.7 and 10.1 minutes for BRV (200 mg, n = 2), and 28 ± 6 minutes for LEV (1500 mg, n = 6). Estimated corrected half-times were 8 minutes shorter. The SO was 66%-70% for 100 mg intravenous BRV, 84%-85% for 200 mg intravenous BRV, and 78%-84% for intravenous 1500 mg LEV. The IC50 of BRV (0.46 µg/mL) was 8.7-fold lower than of LEV (4.02 µg/mL). BRV data fitted a single SO versus plasma concentration relationship. Steady state SO for 100 mg BRV was 86%-87% (peak) and 76%-82% (trough). SIGNIFICANCE: BRV achieves high SO more rapidly than LEV when intravenously administered at therapeutic doses. Thus, BRV may have utility in treating acute seizures; further clinical studies are needed for confirmation.

Toxicokinetics of N-ethyl-2-pyrrolidone and its metabolites in blood, urine and amniotic fluid of rats after oral administration.

The toxicokinetics of N-ethyl-2-pyrrolidone (NEP), an embryotoxic organic solvent, has been studied in Sprague-Dawley rats after oral exposure. NEP and its metabolites 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI) were measured in plasma of pregnant and non-pregnant rats, and fetuses after NEP administration by gavage for 14 consecutive days at 50 mg/kg/day, and in plasma of non-pregnant rats after a single NEP administration. Additionally, amniotic fluid and 24-h urine samples of the pregnant rats were analyzed for NEP metabolites. Furthermore, 24-h urine samples from a repeated dose 28-day oral toxicity study in female (non-pregnant) and male rats administered developmentally non-toxic (0, 5, and 50 mg/kg/day) or toxic (250 mg/kg/day) doses of NEP were analyzed. Median peak plasma concentrations in non-pregnant rats after a single dose and repeated doses were 551 and 611 (NEP), 182 and 158 (5-HNEP), and 63.8 and 108 µmol/L (2-HESI), respectively; whereas in pregnant rats and fetuses 653 and 619 (NEP), 80.5 and 91.7 (5-HNEP) and 77.3 and 45.7 µmol/L (2-HESI) were detected. Times to reach maximum plasma concentrations for NEP, 5-HNEP, and 2-HESI were 1, 4, and 8 h, respectively, and were comparable to N-methyl-2-pyrrolidone (NMP) and its corresponding metabolites. In pregnant rats, plasma elimination of NEP and metabolite formation/elimination was much slower compared to non-pregnant rats and efficient placental transfer of NEP was observed. Our data, overall, suggest differences in the toxicokinetics of chemicals between pregnant and non-pregnant rats which need to be addressed in risk assessment, specifically when assessing developmental toxicants such as NEP.

Simultaneous Detection and Quantification of Three Novel Prescription Drugs of Abuse (Suvorexant, Lorcaserin and Brivaracetam) in Human Plasma by UPLC-MS-MS.

Suvorexant (SVR), lorcaserin (LCR) and brivaracetam (BVR) have been recently approved for the treatment of insomnia, obesity and epilepsy, respectively. Despite their clinical uses, these drugs have some abuse potential and have been enlisted under the schedule IV (SVR, LVR) and schedule V (BVR) categories of the Controlled Substances Act. A sensitive UPLC-MS-MS assay was developed for simultaneously determining SVR, LCR and BVR in human plasma. The liquid-liquid extraction method, using tert-butyl methyl ether as an extracting solvent, was used for sample preparation. Chromatographic separation was performed by using the Acquity BEH C18 column, using 10 mM ammonium acetate/acetonitrile/formic acid (15/85/0.1%; v/v/v) as the mobile phase. For sample ionization, electrospray ionization was used in the positive-ion mode. The multiple-reaction monitoring mode was used for detecting and quantifying analytes by using separate precursor-to-product ion transitions. The assay was validated following the SWGTOX guidelines, and all validation results were within the acceptable limits. The calibration curves of the analytes in the plasma were found to be linear, and the coefficient of determination (R2) was ≥ 0.992 for all the three analytes. The limit of detection values for SVR, LCR and BVR were 0.08, 0.11 and 0.26 ng/mL, respectively, whereas the limit of quantification values were 0.16, 0.27 and 0.65 ng/mL, respectively. The assay developed in this study is suitable for the identification and quantification of SVR, LCR and BVR in the forensic laboratory.

Intravenous brivaracetam in status epilepticus: Correlation between loading dose, plasma levels and clinical response.

Brivaracetam is available in intravenous formulation, and its favourable pharmacokinetic profile makes it a promising agent in the treatment of status epilepticus (SE). Its availability as an intravenous formulation and its favourable pharmacokinetic profile make it a promising agent in the treatment of status epilepticus. Our aim was to assess the correlation between BRV exposure and clinical response. We retrospectively studied all consecutive SE patients treated with BRV in our centre from September 2016 to March 2018. Correlations between loading doses, plasma concentrations, extrapolated exposures (approach based on a population pharmacokinetics model) and the clinical response (defined as BRV being able to resolve SE without the need of further treatment), were analysed. Among 14 patients, 7 (50%) responded to BRV. Responders received significantly greater median loading dosage per body weight (3.3 mg/kg) compared to non-responders (1.5 mg/kg) (p = 0.02); no responders had loading doses below 1.9 mg/kg. There was a significant correlation of the clinical response with calculated exposure parameters, whereas measured BRV concentrations did not. BRV doses higher than 1.9 mg/kg are associated with greater probabilities of response in SE; consequently, a minimum dose of 2 mg/kg seems advisable in treatment of SE. It is unclear whether increasing further BRV loading doses would provide any additional benefit. BRV concentrations performed outside the frame of a standardised protocol merely ascertain BRV administration. This study is however limited by its small sample size.

Brivaracetam-induced elevation of carbamazepine epoxide levels: A post-hoc analysis from the clinical development program.

To assess the association, if any, between brivaracetam (BRV)-induced elevated carbamazepine-10,11-epoxide (CBZ-E) and toxicity and efficacy in patients with epilepsy. Data were pooled from three double-blind, placebo-controlled, Phase III studies of adjunctive BRV in adults with uncontrolled focal seizures (N01252/NCT00490035, N01253/NCT00464269, N01358/NCT01261325). Treatment-emergent adverse events (TEAEs) of interest (ataxia, diplopia, dizziness, nystagmus, somnolence, accidental overdose or poisoning, and toxicity), discontinuations due to TEAEs, and serious TEAEs (SAEs) were assessed in subgroups who did/did not receive carbamazepine (CBZ) at study entry (CBZ+ and CBZ-). Logistic regression analysis evaluated CBZ-E/CBZ plasma concentrations and TEAEs. SAEs suggestive of CBZ-E toxicity were summarized from the BRV safety database up to a cut-off of October 1, 2014. Percent reduction in focal seizure frequency over placebo was assessed in subgroups of CBZ-E/CBZ ratios. Data from 1558 patients were included in the pooled safety population. Of these, concomitant CBZ was received by 184/459 (40.1%) placebo-treated and 315/803 (39.2%) BRV-treated patients (≥50 mg/day). In BRV-treated patients, study completion rates were similar in the CBZ+ (92.7%) and CBZ- (88.7%) groups; incidence of TEAEs of interest was similar (CBZ+ 24.4%; CBZ- 24.2%), and did not appear affected by CBZ dosage; SAEs and discontinuations due to TEAEs were CBZ+ 1.6%; CBZ- 3.9% and 2.9%; 9.2%, respectively. Likelihood of TEAEs of interest decreased with increasing CBZ-E/CBZ ratio for BRV-treated patients: odds ratio 0.88 (95% confidence intervals 0.74, 1.03; p = 0.112). In the safety database, five SAEs suggestive of CBZ-E toxicity were identified. Efficacy outcomes did not appear to have a consistent pattern across CBZ-E/CBZ ratio subgroups. This post-hoc analysis does not support an association between CBZ-E levels and TEAEs potentially associated with CBZ-E toxicity, or with increases in efficacy. Overall, current evidence does not suggest that BRV dose adjustment is required with concomitant CBZ.

Evaluation of the pharmacokinetic drug interaction potential of tivantinib (ARQ 197) using cocktail probes in patients with advanced solid tumours.

AIMS: This phase 1, open-label, crossover study sought to evaluate drug-drug interactions between tivantinib and cytochrome P450 (CYP) substrates and tivantinib and P-glycoprotein. METHODS: The effect of tivantinib doses on the pharmacokinetics of the probe drugs for CYP1A2 (caffeine), CYP2C9 (S-warfarin), CYP2C19 (omeprazole), and CYP3A4 (midazolam), and for P-glycoprotein (digoxin) was investigated in 28 patients with advanced cancer using a cocktail probe approach. Patients received single doses of probe drugs alone and, after 5 days of treatment, with tivantinib 360 mg twice daily. RESULTS: The ratios of geometric least squares mean (90% confidence interval) for the area under the concentration-time curve from time zero to the last quantifiable concentration in the presence/absence of tivantinib were 0.97 (0.89-1.05) for caffeine, 0.88 (0.76-1.02) for S-warfarin, 0.89 (0.60-1.31) for omeprazole, 0.83 (0.67-1.02) for midazolam, and 0.69 (0.51-0.94) for digoxin. Similar effects were observed for maximum plasma concentrations; the ratio for digoxin in the presence/absence of tivantinib was 0.75 (0.60-0.95). CONCLUSIONS: The data suggest that tivantinib 360 mg twice daily has either a minimal or no effect on the pharmacokinetics of probe drugs for CYP1A2, CYP2C9, CYP2C19 and CYP3A4 substrates, and decreases the systemic exposure of P-glycoprotein substrates when administered with tivantinib.

UPLC-MS/MS assay for identification and quantification of brivaracetam in plasma sample: Application to pharmacokinetic study in rats.

Brivaracetam (BVR) is a novel antiepileptic drug (AED), approved clinically for the treatment of partial onset seizures in adults and adolescents. It has some abuse potential and assigned to Schedule V category under the Controlled Substance Act by the Drug Enforcement Administration. Being an AED and drug of abuse, a sensitive and robust assay is necessary for determination of BVR in biological fluids. Herein, we report a sensitive and validated UPLC-MS/MS assay for identification and quantification of BVR in plasma samples. The samples were prepared by one step liquid liquid extraction method using tert-Butyl methyl ether as extracting solvent. BVR and internal standard (carbamazepine) were separated on Aquity BEH™ C-18 column and eluted by using gradient mobile phase combination of acetonitrile and 0.1% formic acid in water. The precursor to product ion transition of m/z 213.12→54.95 (qualifier), 213.12→168.10 (quantifier) for BVR, and m/z 237.06→193.25 for IS were used for MRM detection and quantification. The assay was validated according to USFDA and SWGTOX guidelines for method validation and all parameter results were within the acceptable limits. The calibration curves were found to be linear in concentration range of 1.98-2000ng/mL (r2≥0.995) having LOD and LLOQ of 0.80 and 1.98ng/mL, respectively. The assay was successfully employed in BVR pharmacokinetic study in rats and can be suitable for therapeutic drug monitoring, pharmacokinetic study and forensic analysis.

Positron emission tomography measurement of brain MAO-B inhibition in patients with Alzheimer's disease and elderly controls after oral administration of sembragiline.

PURPOSE: In Alzheimer's disease (AD), increased metabolism of monoamines by monoamine oxidase type B (MAO-B) leads to the production of toxic reactive oxygen species (ROS), which are thought to contribute to disease pathogenesis. Inhibition of the MAO-B enzyme may restore brain levels of monoaminergic neurotransmitters, reduce the formation of toxic ROS and reduce neuroinflammation (reactive astrocytosis), potentially leading to neuroprotection. Sembragiline (also referred as RO4602522, RG1577 and EVT 302 in previous communications) is a potent, selective and reversible inhibitor of MAO-B developed as a potential treatment for AD. METHODS: This study assessed the relationship between plasma concentration of sembragiline and brain MAO-B inhibition in patients with AD and in healthy elderly control (EC) subjects. Positron emission tomography (PET) scans using [11C]-L-deprenyl-D2 radiotracer were performed in ten patients with AD and six EC subjects, who received sembragiline each day for 6-15 days. RESULTS: At steady state, the relationship between sembragiline plasma concentration and MAO-B inhibition resulted in an Emax of ∼80-90 % across brain regions of interest and in an EC50 of 1-2 ng/mL. Data in patients with AD and EC subjects showed that near-maximal inhibition of brain MAO-B was achieved with 1 mg sembragiline daily, regardless of the population, whereas lower doses resulted in lower and variable brain MAO-B inhibition. CONCLUSIONS: This PET study confirmed that daily treatment of at least 1 mg sembragiline resulted in near-maximal inhibition of brain MAO-B enzyme in patients with AD.

A phase I study of tivantinib in combination with temsirolimus in patients with advanced solid tumors.

Background A wide variety of human cancers exhibit dysregulated c-Met activity that has implications in oncogenesis. Phosphorylation of c-Met results in activation of the PI3K/AKT/mTOR pathway. Combined blockade of c-Met and mTOR pathways has shown efficacy in preclinical studies. Tivantinib is a c-Met inhibitor and temsirolimus is a selective mTOR inhibitor. We aimed to determine the maximum tolerated dose (MTD) and the recommended phase II dose (RP2D), dose-limiting toxicities (DLT), adverse events (AEs), clinical activity and pharmacokinetic (PK) parameters of the combination. Methods This open-label phase I study used a 3 + 3 dose escalation design. Patients (pts) were treated with escalating doses of tivantinib (120-360 mg tablets orally twice daily) and temsirolimus (20 mg IV weekly) followed by dose expansion at the MTD. Separate cohorts were planned for extensive (normal) and poor tivantinib metabolizers based on CYP2C19 genotypes. Cycles were 28 days besides cycle 1 that was 35 days to allow for PK analysis. Results Twenty-nine pts. [median age 58 (range 28-77)] were enrolled (21 in dose escalation and 8 in dose expansion). All were extensive CYP2C19 metabolizers. The most common types of cancer were colorectal, ovarian and non-small cell lung. Sixteen out of 21 and 6 out of 8 pts. were evaluable for DLT evaluation per protocol in the dose escalation and dose expansion phases, respectively. Pts remained on study for a median of 71 days (range 18-296). The MTD and RP2D was tivantinib 240 mg twice daily and temsirolimus 20 mg weekly. DLTs included grade (gr) 4 neutropenia (2 pts.; 1 with gr 3 febrile neutropenia), gr 3 abdominal pain (1 pt) and gr 2 mucositis resulting in inadequate drug delivery. The most common treatment related AEs grade ≥ 2 included: anemia (gr 2 in 9 pts., gr 3 in 3 pts), fatigue (gr 2 in 10 pts), anorexia (gr 2 in 9 pts), hypoalbuminemia (gr 2 in 6 pts., gr 3 in 2 pts), hypophosphatemia (gr 2 in 2 pts., gr 3 in 5 pts) and nausea (gr 2 in 6 pts., gr 3 in 1 pt). One pt. with ovarian cancer had a confirmed partial response and remained on study for 10 months, a second patient with ovarian cancer had stable disease and remained on study for 6 months and a third pt. with squamous cell carcinoma of the tongue had stable disease and remained on study for 7 months. Pharmacokinetic analysis showed that there is no interaction in the plasma concentrations between tivantinib and temsirolimus. Conclusions The combination of tivantinib with temsirolimus appears to be well tolerated with evidence of clinical activity.

Pharmacokinetic interaction of brivaracetam on carbamazepine in adult patients with epilepsy, with and without valproate co-administration.

OBJECTIVE: This Phase I, open-label, dose-escalation study investigated the effects of steady-state brivaracetam on the pharmacokinetics of carbamazepine in patients with epilepsy, with and without valproate co-administration. Valproate and brivaracetam inhibit epoxide hydrolase and increase carbamazepine epoxide levels. METHODS: Adult patients with epilepsy being chronically treated with carbamazepine alone (n=9) or with carbamazepine and valproate (n=9) received brivaracetam during successive 1-week periods at doses of 50mg, 100mg, 200mg, and 100mg twice daily (bid). Doses of carbamazepine and valproate must have been stable for at least 3 months. Trough plasma concentrations of carbamazepine, carbamazepine epoxide, and diol metabolites were determined on Days 1, 8, 15, 22, and 29, and at the end of study visit (ESV, 2-3weeks later). RESULTS: Eighteen patients with median (range) age of 45 (20-62) years and body weight of 74 (59-124) kg were enrolled and completed the study. In patients treated with carbamazepine alone, brivaracetam dose-dependently increased mean trough levels of carbamazepine epoxide from 1.38µg/mL on Day 1 pre-dose to 2.16µg/mL (+57%) on Day 8 (50mg bid), 2.72µg/mL (+97%) on Day 15 (100mg bid), 3.02µg/mL (+119%) on Day 22 (200mg bid), 2.67µg/mL (+94%) on Day 29 (100mg bid), and 1.22µg/mL (-12%) at ESV, respectively. In patients on carbamazepine and valproate, carbamazepine epoxide increased from 1.98µg/mL at baseline to 2.72µg/mL (+37%), 3.70µg/mL (+87%), 4.43µg/mL (+124%), 3.11µg/mL (+57%), and 1.94µg/mL (-2%), respectively. There was no trend for change in carbamazepine, carbamazepine diol or valproate levels. Brivaracetam levels increased linearly with dose. Brivaracetam was well tolerated. CONCLUSIONS: Carbamazepine epoxide plasma concentrations were approximately doubled by brivaracetam 100 or 200mg bid. Data are consistent with a dose-dependent and reversible inhibition of epoxide hydrolase by brivaracetam. Carbamazepine epoxide was approximately 0.7µg/mL higher in presence of valproate. There is no need to limit brivaracetam dosing when used concomitantly with carbamazepine.

Bioavailability and bioequivalence comparison of brivaracetam 10, 50, 75, and 100 mg tablets and 100 mg intravenous bolus.

OBJECTIVE: To determine the bioequivalence of brivaracetam oral tablet formulations (10, 75, and 100 mg) versus 50 mg oral tablet and to compare the bioavailability of brivaracetam 100 mg intravenous (i.v.) bolus versus 50 and 100 mg tablets, in healthy participants. METHODS: Phase 1, randomized, open-label, five-period crossover study. Participants received five single doses of brivaracetam: 10, 50 (reference), 75, and 100 mg oral tablets; 100 mg, i.v., bolus injection. Pharmacokinetic parameters (maximum plasma concentration [Cmax ], area under the plasma concentration-time curve from time zero to the time of last quantifiable concentration [AUCt ], area under the plasma concentration-time curve extrapolated to infinity [AUCinf ]) were compared using analysis of variance (ANOVA) following dose normalization and logarithmic transformation. Bioavailability comparisons were based on the 90% confidence intervals (CIs) around the geometric least squares mean ratios (test: reference). RESULTS: Twenty-five participants were randomized. The 90% CIs around Cmax , AUCt , and AUCinf ratios for brivaracetam 10, 75, and 100 mg tablets versus 50 mg tablet were entirely contained within the bioequivalence limits (0.8000-1.2500). For brivaracetam 100 mg, i.v., bolus, bioequivalence versus 50 and 100 mg tablets was met for AUCt and AUCinf , but Cmax was partly outside the limits (90% CI: 1.1867-1.3863 and 1.1222-1.3136, respectively). SIGNIFICANCE: Brivaracetam 10, 75, and 100 mg tablets were bioequivalent to the 50 mg tablet. Brivaracetam 100 mg, i.v., bolus had bioavailability similar to that of 50 and 100 mg tablets.

Quantitative analysis of tivantinib in rat plasma using ultra performance liquid chromatography with tandem mass spectrometry.

In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitative determination of tivantinib in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an Acquity UPLC BEH C18 (2.1mm×50mm, 1.7µm) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 1.0-100ng/mL (r(2)>0.9967) with a lower limit of quantification (1.0ng/mL). The extraction recovery was in the range of 79.4-84.2% for tivantinib and 80.3% for carbamazepine (internal standard, IS). The intra- and inter-day precision was below 8.9% and accuracy was from -7.2% to 9.5%. No notable matrix effect and astaticism was observed for tivantinib. The method has been successfully applied to a pharmacokinetic study of tivantinib in rats for the first time, which provides the basis for the further development and application of tivantinib.

Safety and tolerability of adjunctive brivaracetam as intravenous infusion or bolus in patients with epilepsy.

OBJECTIVES: An intravenous (IV) formulation of brivaracetam (BRV), a selective, high-affinity ligand for synaptic vesicle protein 2A, has been developed. We investigated the safety, tolerability, and pharmacokinetics of adjunctive IV BRV administered as a bolus or infusion to adults with epilepsy. METHODS: A phase III, multicenter, randomized, four-arm, parallel-group study (NCT01405508) of patients aged 16-70 years with focal or generalized epilepsy uncontrolled by 1-2 antiepileptic drugs was undertaken. The study comprised a 7-day baseline period, a 7-day double-blind run-in period (oral BRV 200 mg/day or placebo [PBO] twice daily [BID]), and 4.5-day open-label evaluation period (IV BRV 200 mg/day BID; 2-min bolus or 15-min infusion, total nine doses). Patients were randomized 1:1:1:1 PBO/BRV bolus; PBO/BRV infusion; BRV/BRV bolus; BRV/BRV infusion. Safety and tolerability were assessed using adverse events, electrocardiography, vital signs, and laboratory assessments. BRV plasma concentrations were measured before and 15 min after the first and last IV doses. RESULTS: Of the 105 patients randomized (53.3% women; 77.1% white; mean [standard deviation; SD] age 41.6 [12.2] years), 103 (98.1%) completed the study. Treatment-emergent adverse event (TEAE) incidence during IV BRV was similar whether IV BRV was initiated first (70.6%) or followed oral BRV (66.0%), and whether it was administered as a bolus (71.2%) or infusion (65.4%). Injection-related TEAEs were reported by 9.6% of patients following bolus and 11.5% following infusion. No serious TEAEs were reported. IV BRV plasma concentrations were higher after the first dose in the conversion groups than initiation groups, and slightly higher in the bolus arm than the infusion arm; concentrations were similar in all patients after the last IV dose. SIGNIFICANCE: IV BRV was generally well tolerated, with similar tolerability as a bolus or infusion and independent of de novo administration or as conversion from oral BRV tablets. IV BRV may be an option for patients who are unable to receive oral BRV.