Clinical pharmacology of psychotropic drugs

Investigation of Safety and Tolerability of ASP3652 Based on Clinical Studies of Cerebrospinal Fluid Transfer After Multiple Doses and Exposure After Single Doses at High Dose Levels

INTRODUCTION

The studies described here were conducted to investigate the central nervous system (CNS) transfer of ASP3652, a peripherally acting inhibitor of fatty acid amide hydrolase, after multiple doses at around the anticipated therapeutic dose and the safety, tolerability, and pharmacokinetics after single doses at corresponding supratherapeutic doses in healthy subjects.

METHODS

Study 1 was an open-label multiple dose study in which ASP3652 (300 mg bid) or matching placebo was administered in multiple doses to healthy subjects. Study 2 was a placebo-controlled, randomized 4 × 4 crossover study in which ASP3652 was given as three single ascending doses of ASP3652 (600-1800 mg) or matching placebo to healthy subjects. Levels of ASP3652 and endocannabinoids (eCBs) in plasma, cerebrospinal fluid (CSF) (study 1 only), and safety were evaluated.

RESULTS

In study 1, ASP3652 was readily absorbed to reach C_max at 1 h after dosing. AUC_tau and C_max of ASP3652 in CSF were approximately 0.2% and 0.06% of the AUC_tau and C_max in plasma after multiple doses of ASP3652 300 mg bid. At steady state the area under the response-time curve (AURC) from 0 to 12 h and the maximum response for anandamide in plasma were approximately 550-fold and 230-fold higher than those in CSF. In study 2, the C_max and AUC of ASP3652 increased higher than dose proportionally in subjects receiving 600-1800 mg ASP3652. For eCBs, although the AURC increased less than dose proportionally, maximum plasma levels were comparable across all treatment groups. The incidence of adverse events (AEs) was similar across all treatment groups including the placebo group. There was no evidence of CNS-related side effects.

CONCLUSIONS

ASP3652 showed low CNS penetration at the anticipated therapeutic dose and was well tolerable without any CNS-related AEs at supratherapeutic doses, supporting that the drug can be safely tested at the anticipated therapeutic dose.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02034734 for study 1, NCT01815684 for study 2.

Pharmacodynamic interactions of a solid formulation of sodium oxybate and ethanol in healthy volunteers

AIM

The pharmacologic effects of sodium oxybate (SO) have a number of similarities with those of alcohol. This study evaluated the pharmacodynamic interaction of SMO.IR (a solid immediate release formulation of SO) and alcohol (0.7 (males) or 0.57 (females) g kg(-1) alcohol using 40% vodka).

METHODS

In a randomized, double-blind, double-dummy, crossover trial, 24 healthy volunteers received randomly a) 2.25 g SMO.IR and placebo alcohol preparation, b) 2.25 g f SMO.IR and alcohol, c) 2.25 g SMO.IR matching placebo and alcohol and d) 2.25 g of SMO.IR matching placebo and placebo alcohol preparation. Objective and subjective cognitive parameters, adverse events and vital signs were assessed before, 15 and 165 min after treatment administration.

RESULTS

Alcohol produced the expected cognitive impairment and the expected subjective sedation rapidly after intake (from 15 min). The objective effects of SMO.IR were much less pronounced than those of alcohol. The reverse was observed for subjective complaints, which were related to lesser stimulation and greater sedation. Nevertheless, 165 min after administration this sedation feeling was less with SMO.IR than with alcohol. There was a significant interaction between SMO.IR and alcohol at 15 min (i.e. increase in alertness and stimulation and decrease in sedation). In addition, an isolated mild decrease in digit vigilance accuracy occurred at 165 min post-dose after the combination. The co-administration of SMO.IR and alcohol was safe and well-tolerated.

CONCLUSION

SMO.IR and alcohol have distinct adverse effect profiles. The objective effects of SMO.IR are much less marked than those of alcohol. No deleterious interaction was observed.

Safety, tolerability, pharmacokinetics and pharmacodynamics of ascending single and multiple doses of lecozotan in healthy young and elderly subjects

AIMS

To determine the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of oral immediate release (IR) lecozotan in healthy young and elderly subjects.

METHODS

Three randomized, double-blind, placebo-controlled, sequential, ascending dose Phase I studies of lecozotan were conducted. In a single-dose study, ascending doses of 2, 5 and 10 mg were administered to cohorts of eight young subjects. In the two ascending 14-day multiple-dose studies, 41 young subjects received 0.1, 0.25, 0.5, 1 and 5 mg q12h of lecozotan or placebo and 24 elderly received 0.5 mg and 5 mg q12h of lecozotan or placebo. Assessments included safety evaluations, a complete PK profile and PD.

RESULTS

Lecozotan was safe and well tolerated at steady state up to 5 mg q12. The maximum tolerated dose after multiple doses was >10 mg (5 mg q12). In the single-dose study, the maximum tolerated dose was 10 mg. Dose-limiting mild-to-moderate adverse events included paraesthesia, dizziness and visual disturbances peaking at t(max) and disappearing concomitantly with plasma concentrations. No clinically relevant changes in vital signs, ECG intervals or routine laboratory tests occurred. Lecozotan did not significantly change cognitive function, EEG or hormone levels. PK was characterized by rapid absorption, dose proportionality, extensive distribution and rapid elimination. The mean CL/F was approximately 35% lower in the elderly.

CONCLUSIONS

Lecozotan IR was safe and well tolerated after administration of multiple oral doses up to 5 mg q12h in young and elderly subjects. These results support the development of lecozotan in patients with Alzheimer's disease.

Impaired cognition and attention in adults: pharmacological management strategies

Cognitive psychology has provided clinicians with specific tools for analyzing the processes of cognition (memory, language) and executive functions (attention-concentration, abstract reasoning, planning). Neuropsychology, coupled with the neurosciences (including neuroimaging techniques), has authenticated the existence of early disorders affecting the "superior or intellectual" functions of the human brain. The prevalence of cognitive and attention disorders is high in adults because all the diseases implicating the central nervous system are associated with cognitive correlates of variable intensity depending on the disease process and the age of the patient. In some pathologies, cognitive impairment can be a leading symptom such as in schizophrenia, posttraumatic stress disorder or an emblematic stigmata as in dementia including Alzheimer's disease. Paradoxically, public health authorities have only recognized as medications for improving cognitive symptoms those with proven efficacy in the symptomatic treatment of patients with Alzheimer's disease; the other cognitive impairments are relegated to the orphanage of syndromes and symptoms dispossessed of medication. The purpose of this review is to promote a true "pharmacology of cognition" based on the recent knowledge in neurosciences. Data from adult human beings, mainly concerning memory, language, and attention processes, will be reported. "Drug therapeutic strategies" for improving cognition (except for memory function) are currently rather scarce, but promising perspectives for a new neurobiological approach to cognitive pharmacology will be highlighted.

Steady-state pharmacokinetics and pharmacodynamics of CHF3381, a novel antineuropathic pain agent, in healthy subjects

AIMS

To evaluate the safety, tolerability, pharmacokinetic and pharmacodynamic profiles of CHF3381, a dual NMDA and MAO-A inhibitor, after multiple oral doses in healthy subjects.

METHODS

Forty-eight young males received CHF3381 at doses of 100 mg twice daily, 200 mg twice daily, 400 mg twice daily or placebo for 2 weeks according to a double-blind, randomized, parallel group design. Plasma and urine concentrations of the parent drug and of two major metabolites (CHF3567 and 2-aminoindane) were measured over time. MAO-A activity in plasma was estimated by measuring plasma concentrations of 3,4-dihydroxyphenylglycol. Sustained attention, memory and sedation were assessed throughout the study with standard psychometric tests.

RESULTS

Most of the adverse events were mild in intensity, with dose regimens of 100 mg twice daily and 200 mg twice daily being indistinguishable from placebo. After 400 mg twice daily, the most frequent adverse events were mild dizziness, asthenia and insomnia. At steady-state, 400 mg twice daily slightly increased supine heart rate (+ 9 +/- 2 beats min(-1)) and diastolic blood pressure (+6 +/- 2 mmHg) compared with placebo. There were no dose-dependent or consistent effects of CHF3381 on attention, motor co-ordination or memory, but 400 mg twice daily significantly decreased alertness compared with placebo. Plasma concentrations of CHF3381 peaked at around 3 h and were dose-proportional. The elimination half-life of CHF3381 was estimated to be 4-6 h. At steady-state, significant CHF3381 plasma concentrations were detected at predose with a modest accumulation (1.3-1.5 times), showing that the drug given twice daily is active over the entire 24 h period. Plasma concentrations of CHF3567 and of 2-aminoindane were also proportional to the dose of CHF3381. CHF3381 dose-dependently inhibited MAO-A activity with peak effects at steady-state of 27 +/- 4%, 46 +/- 2% and 65 +/- 5% after 100 mg twice daily, 200 mg twice daily and 400 mg twice daily, respectively. There were no significant effects of CHF3381 on attention (rapid visual information processing), motor co-ordination (body sway) or memory (learning memory task) at any of the doses. At steady-state, there was a significant decrease in alertness (Bond & Lader visual analogue scale) in the 400 mg twice daily group compared with placebo.

CONCLUSIONS

A twice daily regimen of CHF3381 appears to be adequate from a pharmacokinetic and pharmacodynamic perspective. Plasma concentrations reached with 400 mg twice daily exceeded those observed in animals receiving pharmacologically active doses in chronic pain models.

Postural Instability and Consequent Falls and Hip Fractures Associated with Use of Hypnotics in the Elderly

The aim of this review is to establish the relationship between treatment with hypnotics and the risk of postural instability and as a consequence, falls and hip fractures, in the elderly. A review of the literature was performed through a search of the MEDLINE, Ingenta and PASCAL databases from 1975 to 2005. We considered as hypnotics only those drugs approved for treating insomnia, i.e. some benzodiazepines and the more recently launched 'Z'-compounds, i.e. zopiclone, zolpidem and zaleplon. Large-scale surveys consistently report increases in the frequency of falls and hip fractures when hypnotics are used in the elderly (2-fold risk). Benzodiazepines are the major class of hypnotics involved in this context; falls and fractures in patients taking Z-compounds are less frequently reported, and in this respect, zolpidem is considered as at risk in only one study. It is important to note, however, that drug adverse effect relationships are difficult to establish with this type of epidemiological data-mining. On the other hand, data obtained in laboratory settings, where confounding factors can be eliminated, prove that benzodiazepines are the most deleterious hypnotics at least in terms of their effects on body sway. Z-compounds are considered safer, probably because of their pharmacokinetic properties as well as their selective pharmacological activities at benzodiazepine-1 (BZ(1)) receptors. The effects of hypnotics on balance, gait and equilibrium are the consequence of differential negative impacts on vigilance and cognitive functions, and are highly dose- and time-dependent. Z-compounds have short half-lives and have less cognitive and residual effects than older medications. Some practical rules need to be followed when prescribing hypnotics in order to prevent falls and hip fractures as much as possible in elderly insomniacs, whether institutionalised or not. These are: (i) establish a clear diagnosis of the sleep disorder; (ii) take into account chronic conditions leading to balance and gait difficulties (motor and cognitive status); (iii) search for concomitant prescription of psychotropics and sedatives; (iv) use half the recommended adult dosage; and (v) declare any adverse effect to pharmacovigilance centres. Comparative pharmacovigilance studies focused on the impact of hypnotics on postural stability are very much needed.

Safety, pharmacokinetics, and pharmacodynamics of CHF 3381, a novel N-methyl-D-aspartate antagonist, after single oral doses in healthy subjects

A double-blind, randomized, placebo-controlled study was performed to assess the safety, tolerability, and pharmacokinetics of single oral doses of CHF 3381 in 56 young healthy male volunteers. The central nervous system effects of CHF 3381 were also evaluated, as well as the effect of food on the rate and extent of CHF 3381 absorption. Seven doses of CHF 3381 (25, 50, 100, 200, 300, 450, and 600 mg) were evaluated in an escalating order. At each dose level, 6 subjects were given CHF 3381, and 2 subjects were given placebo. Safety and tolerability evaluation included adverse events, physical examination, vital functions, electrocardiogram, laboratory tests, and 24-hour Holter (100-mg and 450-mg dose panels). Plasma and urinary concentrations of CHF 3381 and its two main metabolites (CHF 3567 and 2-aminoindane) were measured with a validated high-performance liquid chromatography method. Central nervous system effects were evaluated with the simple reaction time (SRT); learning memory task (LMT); Bond & Lader Visual Analog Scale for alertness, contentedness, and calmness; Addiction Research Center Inventory (ARCI); and electroencephalogram. There were no serious adverse events; the most frequent adverse events were dizziness, abnormal thinking, and asthenia. The number of adverse events with moderate intensity increased sharply with the dose, with no or few events up to 450 mg and 17 events with 600 mg. Therefore, 600 mg was defined as the maximum tolerated dose. There were no significant treatment effects on cardiovascular function and electrocardiogram parameters at any CHF 3381 dose or on oral temperature or laboratory tests. There were no clinically significant changes in laboratory variables. CHF 3381 was absorbed rapidly (tmax = 0.5-2 h) and cleared from plasma with a half-life of 3 to 4 hours. Plasma levels of CHF 3381 and its two major metabolites were found to be proportional to the dose. 2-Aminoindane formed slowly and reached much lower concentrations compared to the parent compound and the other metabolite (CHF 3567). Within 48 hours after dosing, 2% to 6% of the administered dose was found in the urine as unchanged drug, about 50% to 55% as the acid derivative (CHF 3567), and 2% to 3% as 2-aminoindane. Ingestion of food did not affect the extent of absorption of the drug, while the rate of absorption was considerably reduced (tmax = 4 h). No significant effects of CHF 3381 were observed on attention (SRT) or memory (LMT). Visual analog scales revealed a decreasing effect of CHF 3381 on alertness at 1 hour that reached statistical significance at 300 and 600 mg. EEG spectral analysis revealed minor decreasing effects of the 200-mg dose on total electric power measured at 2 hours. A stimulant effect was detected by the ARCI scale 24 hours after the 300-mg dose and might be related to the slow formation of the 2-aminoindane metabolite. In conclusion, this study has shown that the maximum tolerated dose of CHF 3381 after single oral administration in young healthy male volunteers is 600 mg. CHF 3381 displays linear pharmacokinetics in the dose range of 25 to 600 mg. The compound is rapidly absorbed and cleared from plasma with a half-life of 3 to 4 hours. The ingestion of food seems to not affect the extent of absorption of the drug. Minor effects on the central nervous system were detected at doses equal to or greater than 300 mg.

Pharmacodynamic profile of Zaleplon, a new non-benzodiazepine hypnotic agent

The challenge in developing hypnotic agents for the treatment of insomnia is to balance the sedative effect needed at bedtime with the residual sedation on awakening. Zaleplon is a novel pyrazolopyrimidine hypnotic agent that acts as a selective agonist to the brain omega(1) receptor situated on the alpha(1) subunit of the GABA(A) receptor complex. Zaleplon was proven to be an effective hypnotic drug as it consistently and significantly reduced latency to persistent sleep in insomniac patients for doses of 10 mg and above in polysomnography studies. The pharmacodynamic profile of zaleplon on psychomotor performance, actual driving and cognitive function, including memory, was assessed in several randomized, double-blind, placebo-controlled studies in healthy young subjects as well as insomniac patients by using various positive controls (zolpidem, zopiclone, triazolam and flurazepam). The recommended hypnotic dose of zaleplon in young adults (10 mg) produced minimal or no impairment of psychomotor and memory performance even when administered during the night as little as 1 h before waking. No impairment of actual driving was observed when zaleplon 10 mg was administered either at bedtime or in the middle of the night as little as 4 h before waking. Zaleplon 20 mg, twice the recommended dose, generally produced significant impairment of performance and cognitive functions when these functions were measured at the time of peak plasma concentration, i.e. 1 h after dose administration, and no impairment of driving abilities was observed 4 h after a middle-of-the-night administration. In contrast, consistent detrimental residual effects on various aspects of psychomotor and cognitive functions were observed with the therapeutic doses of the various commonly prescribed hypnotic agents used as comparators, e.g. zolpidem 10 mg up to 5 h after dose administration, zopiclone 7.5 mg up to 10 h after, flurazepam 30 mg up to 14 h after and triazolam 0.25 mg up to 6 h after. Also, zolpidem 10 mg and zopiclone 7.5 mg were also shown to significantly impair driving ability the next morning when this was measured 4 h and up to 10 h after dose administration, respectively. The present review shows that zaleplon 10 mg has little or no residual effect when administered in the middle of the night, as late as 1 h before waking, and is devoid of impairment of driving abilities as assessed by actual driving 4 h after dose administration. The lack of clinically significant or minimally statistically significant residual effects of zaleplon even at its peak concentration may be explained by its unique pharmacokinetic (rapid elimination half-life) and pharmacodynamic (low affinity, and specific binding profile to various subunits of the GABA(A)receptor) profiles. These properties allow zaleplon to be used for treatment of symptoms only when they occur, either at bedtime or later in the night, without incurring significant risk of developing next-day impairment of psychomotor and cognitive functioning. Copyright 2001 John Wiley & Sons, Ltd.

Residual effects of zaleplon and zolpidem following middle of the night administration five hours to one hour before awakening

The objective was to assess residual effects of zaleplon and zolpidem after a middle of the night administration. This was a randomized, double-blind, placebo-controlled, crossover study, conducted in 40 healthy young male and female subjects. Subjects were awakened in the middle of the night and administered either placebo or zaleplon 10 or 20 mg or zolpidem 10 mg. A battery of objective tests exploring psychomotor and cognitive functions such as critical flicker fusion (CFF), choice reáction time (CRT), digit symbol substitution test (DSST), and memory tests (Sternberg memory scanning and a word list) were administered immediately after morning waking. Zaleplon 10 mg was devoid of residual effects whatever - the time of dosing - except a minimal but significant decrease in DSST scores when administered 1 h before awakening. Zaleplon 20 mg produced significant residual effects on performance (increase in CRT, and decrease in CFF threshold and in DSST scores) and memory (decrease in immediate and delayed free recall of words) only when administered 1 h before awakening. In contrast, zolpidem 10 mg produced significant detrimental residual effects on CRT and delayed free recall of words, when administered up to 5 h before waking, on DSST and Sternberg when administered up to 3 h before awakening and on CFF when administered 1 h before awakening. The residual effects of zolpidem 10 mg were more marked than those observed after zaleplon 20 mg. The present results demonstrate that zaleplon 10 mg has no or minimal residual effects when administered in the middle of the night as little as 1 h before waking. The lack of clinically significant residual effects with zaleplon may be explained by its unique pharmacokinetic (rapid elimination half-life) and pharmacodynamic (selective binding for GABA(A) receptors with the alpha(1) subunit, dissociation between sleep inducing properties and impairment of cognitive functions) profiles. Copyright 2001 John Wiley & Sons, Ltd.