An alternative start regimen with aripiprazole once-monthly in patients with schizophrenia: population pharmacokinetic analysis of a single-day, two-injection start with gluteal and/or deltoid intramuscular injection.

BACKGROUND: The single-injection start regimen for aripiprazole once-monthly 400 mg (AOM 400) in patients with schizophrenia requires a single intramuscular injection in the gluteal or deltoid site and 14 days of concurrent oral therapy. A simplified, single-day regimen of two injections at separate gluteal and/or deltoid injection sites, together with a single 20-mg dose of oral aripiprazole on the 1st day, was assessed. PATIENTS AND METHODS: A previously developed population-pharmacokinetic (popPK) model for characterizing aripiprazole PK following oral administration and gluteal intramuscular depot injection was expanded to include deltoid injection. Simulations were conducted to assess PK profiles following various (including two-injection) start regimens. Postmarketing data on patients who received higher-than-recommended AOM doses were used to assess overall safety/tolerability. RESULTS: The two-injection start regimen with a single concurrent oral dose displayed a comparable PK profile to the single-injection start regimen with concurrent 14-day oral administration in simulations. The safety assessment indicated the two-injection start regimen was unlikely to be associated with safety concerns beyond those expected with a single-injection start regimen. CONCLUSION: These data support use of the two-injection start regimen in clinical practice to reduce reliance on daily oral administration and optimize the therapeutic benefits of AOM 400 in patients with schizophrenia.

A positron emission tomography occupancy study of brexpiprazole at dopamine D2 and D3 and serotonin 5-HT1A and 5-HT2A receptors, and serotonin reuptake transporters in subjects with schizophrenia.

The objective of this study (NCT01854944) was to assess D2/D3, 5-HT1A, 5-HT2A and serotonin transporter (SERT) occupancies of brexpiprazole in adult subjects with schizophrenia in order to identify the in vivo pharmacologic profile that may be relevant to the antipsychotic, antidepressant, and side effect profiles of the drug. Subjects were grouped into three independent cohorts of four subjects each. All subjects underwent positron emission tomography (PET) scans with two different radiotracers at baseline prior to brexpiprazole administration, and again on Day 10 after daily doses of either 4 mg (Cohorts 1 and 2), or 1 mg (Cohort 3). Cohort 1 received scans with [11C]-(+)-PHNO to measure D2 and D3 receptor occupancy and [11C]CUMI101 to measure 5-HT1A occupancy; Cohort 2 received [11C]MDL100907 for 5-HT2A occupancy and [11C]DASB for SERT occupancy; Cohort 3 underwent scanning with [11C]-(+)-PHNO and [11C]MDL100907. Five female and seven male subjects, aged 42 ± 8 years (range, 28-55 years), participated in this study. Dose dependency was observed at D2 receptors, with occupancies reaching 64 ± 8% (mean +/- SD) following 1 mg/day and 80 ± 12% following 4 mg/day. D3 receptor availability increased following 1 mg brexpiprazole treatment and did not change with 4 mg. Robust and dose-related occupancy was also observed at 5-HT2A receptors. Negligible occupancy (<5%) was observed at 5-HT1A and SERT at 4 mg/day. In summary, brexpiprazole demonstrated in vivo binding to D2 receptors and 5-HT2A receptors at steady state after 10 days of daily administration in a dose dependent manner, while binding to D3, 5-HT1A receptors and SERT was not detectable with the radiotracers used for these targets. This pharmacologic profile is consistent with the observed antipsychotic and antidepressant effects.

A Long-Term, Open-Label Study to Evaluate the Safety and Tolerability of Brexpiprazole as Maintenance Treatment in Adults with Schizophrenia.

Background: Brexpiprazole is a serotonin-dopamine activity modulator with efficacy in acute schizophrenia and relapse prevention. The aim of this Phase 3, multicenter study was to assess the long-term safety, tolerability, and efficacy of treatment with brexpiprazole flexible-dose 1-4 mg/d. Methods: Patients rolled over into this 52-week open-label study (amended to 26 weeks towards the end) from 3 randomized, double-blind, placebo-controlled Phase 3 studies. De novo patients, not part of the previous studies, were also enrolled. The primary outcome variable was the frequency and severity of treatment-emergent adverse events. Efficacy was assessed as a secondary objective using the Positive and Negative Syndrome Scale and the Personal and Social Performance scale. Results: A total of 1072 patients was enrolled (952 for 52 weeks and 120 for 26 weeks), 47.4% of whom completed the study. Among patients who took at least one dose of brexpiprazole, 14.6% discontinued due to treatment-emergent adverse events, most commonly schizophrenia (8.8%) and psychotic disorder (1.5%). Treatment-emergent adverse events with an incidence of ≥5% were schizophrenia (11.6%), insomnia (8.6%), weight increased (7.8%), headache (6.4%), and agitation (5.4%). Most treatment-emergent adverse events were mild or moderate in severity. The mean increase in body weight from baseline to week 26 was 1.3 kg and to week 52 was 2.1 kg. There were no clinically relevant findings related to prolactin, lipids, and glucose, or QT prolongation. On average, patients' symptoms and functioning showed continual improvement. Conclusions: Treatment with brexpiprazole 1-4 mg/d was generally well tolerated for up to 52 weeks in patients with schizophrenia. ClinicalTrials.gov identifier: NCT01397786 (https://clinicaltrials.gov/show/NCT01397786).

Efficacy and Safety of Brexpiprazole (OPC-34712) as Maintenance Treatment in Adults with Schizophrenia: a Randomized, Double-Blind, Placebo-Controlled Study.

Background: Brexpiprazole has previously demonstrated efficacy in acute schizophrenia trials. The objective of this trial was to assess the efficacy, safety, and tolerability of maintenance treatment with brexpiprazole in adults with schizophrenia. Methods: Patients with an acute exacerbation of psychotic symptoms were converted to brexpiprazole (1-4mg/d) over 1 to 4 weeks and entered a single-blind stabilization phase. Those patients who met stability criteria for 12 weeks were randomized 1:1 to double-blind maintenance treatment with either brexpiprazole (at their stabilization dose) or placebo for up to 52 weeks. The primary efficacy endpoint was the time from randomization to impending relapse. Safety and tolerability were also assessed. Results: A total of 524 patients were enrolled, 202 of whom were stabilized on brexpiprazole and randomized to brexpiprazole (n=97) or placebo (n=105). Efficacy was demonstrated at a prespecified interim analysis (conducted after 45 events), and so the trial was terminated early. The final analysis showed that time to impending relapse was statistically significantly delayed with brexpiprazole treatment compared with placebo (P<.0001, log-rank test). The hazard ratio for the final analysis was 0.292 (95% confidence interval: 0.156, 0.548); mean dose at last visit, 3.6mg. The proportion of patients meeting the criteria for impending relapse was 13.5% with brexpiprazole and 38.5% with placebo (P<.0001). During the maintenance phase, the incidence of adverse events was comparable to placebo. Conclusions: or patients with schizophrenia already stabilized on brexpiprazole, maintenance treatment with brexpiprazole was efficacious, with a favorable safety profile.

Effects of chicory/perennial ryegrass swards compared with perennial ryegrass swards on the performance and carcass quality of grazing beef steers.

An experiment investigated whether the inclusion of chicory (Cichorium intybus) in swards grazed by beef steers altered their performance, carcass characteristics or parasitism when compared to steers grazing perennial ryegrass (Lolium perenne). Triplicate 2-ha plots were established with a chicory/ryegrass mix or ryegrass control. Forty-eight Belgian Blue-cross steers were used in the first grazing season and a core group (n = 36) were retained for finishing in the second grazing season. The experiment comprised of a standardisation and measurement period. During standardisation, steers grazed a ryegrass/white clover pasture as one group. Animals were allocated to treatment on the basis of liveweight, body condition and faecal egg counts (FEC) determined 7 days prior to the measurement period. The measurement period ran from 25 May until 28 September 2010 and 12 April until 11 October 2011 in the first and second grazing year. Steers were weighed every 14 days at pasture or 28 days during housing. In the first grazing year, faecal samples were collected for FEC and parasite cultures. At the end of the first grazing year, individual blood samples were taken to determine O. ostertagi antibody and plasma pepsinogen levels. During winter, animals were housed as one group and fed silage. In the second grazing year, steers were slaughtered when deemed to reach fat class 3. Data on steer performance showed no differences in daily live-weight gain which averaged 1.04 kg/day. The conformation, fat grade and killing out proportion of beef steers grazing chicory/ryegrass or ryegrass were not found to differ. No differences in FEC, O. ostertagi antibody or plasma pepsinogen levels of beef steers grazing either chicory/ryegrass or ryegrass were observed. Overall, there were no detrimental effects of including chicory in swards grazed by beef cattle on their performance, carcass characteristics or helminth parasitism, when compared with steers grazing ryegrass.

Multivariate analysis of bipolar mania: retrospectively assessed structure of bipolar I manic and mixed episodes in randomized clinical trial participants.

BACKGROUND: Manic episodes are heterogeneous. Mixed states may differ in important clinical characteristics from other manic episodes. However, it has not been established whether mixed states are a distinct type of episodes, or a common basic structure exists across manic episodes. METHODS: Using 2179 well-characterized subjects in the pretreatment phase of six randomized, clinical trials, we conducted rotated factor analysis followed by cluster analysis, using all items from the Young Mania Rating Scale and the Montgomery-Åsberg Depression Scale. Analyses were conducted for all subjects (n=2179) and for those in Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition (DSM-IV) mixed (n=644) and non-mixed (n=1535) episodes separately. RESULTS: There were five factors characterized (in order of variance accounted for) as depression, mania, sleep disturbance, judgment/impulsivity and irritability/hostility. Cluster analysis identified five clusters. Three were predominately manic, with depression scores below average for the overall group. Two had high average depression scores; these clusters differed in irritability/hostility. Judgment/impulsivity scores were similar across factors. Essentially identical factors and clusters existed whether analyses were done in all subjects or only in subjects classified by DSM-IV as mixed or non-mixed. LIMITATIONS: Exclusion criteria of studies may limit generalizability of findings. DISCUSSION: All manic episodes, whether mixed or non-mixed, shared a similar structure according to factor/cluster analysis. Patients with high depression factor scores were heterogeneous with respect to irritability. These data suggest that depressive symptoms should be considered a dimensional property across manic episodes, rather than as defining a specific type of episode.

Aripiprazole as adjunctive therapy for patients with major depressive disorder: overview and implications of clinical trial data.

Aripiprazole was initially approved to treat schizophrenia and later approved for bipolar mania, as a monotherapy and an adjunctive therapy (manic or mixed episodes), and for irritability associated with autism. Aripiprazole is a partial agonist at dopamine D(2) and D(3) and serotonin 5-HT(1A) receptors, and is an antagonist at 5-HT(2A) receptors. This profile, and convincing preliminary data from small-scale studies, provided the rationale for the large-scale exploration of aripiprazole for unipolar depression. Recently, three 6-week, large-scale, randomized, double-blind, placebo-controlled clinical trials demonstrated clinically meaningful efficacy for aripiprazole as an adjunctive therapy to antidepressants for treating major depressive disorder (MDD). In November 2007, aripiprazole was approved by the US FDA as an adjunctive therapy to antidepressants for treating MDD, with support from two of the above-mentioned trials. In the trials, aripiprazole was demonstrated to be safe and well tolerated, and showed a minimal trend for weight gain over the course of a 6-week treatment. The incidence of akathisia was higher than that reported in studies of patients with schizophrenia; however, most cases were mild to moderate and infrequently lead to discontinuation (5/1090 from all three trials). This comprehensive review provides an overview of the data from all three 6-week studies (including a pooled analysis) and from an unpublished 52-week, open-label extension study, to inform physicians and facilitate reasonable treatment decisions. In addition, specific issues associated with the use of aripiprazole as an adjunctive therapy in patients with MDD, including possible early treatment effect, appropriate timing of therapy initiation, appropriate dosing and duration of treatment, possible differential effect on depressive subgroups and long-term tolerability, are also discussed.

Aripiprazole attenuates established behavioral sensitization induced by methamphetamine.

Psychostimulant-induced behavioral sensitization is an experimental model of the stimulant psychosis and the vulnerability to relapse in schizophrenia. This study investigated the effects of aripiprazole, an antipsychotic drug that has dopamine D2 receptor partial agonist activity, on established sensitization induced by methamphetamine (MAP) in mice. Repeated treatment with MAP (1.0mg/kg, s.c.) for 10 days progressively increased the ability of MAP to increase locomotor activity. The enhanced locomotion induced by a challenge dose of MAP (0.24 mg/kg, s.c.) also occurred after withdrawal from MAP pretreatment. Repeated treatment with aripiprazole from days 10 to 14 during withdrawal from MAP administration attenuated the effect of MAP pretreatment, enhancing the motor response to a challenge dose of stimulant 3 days after the aripiprazole preparation. In contrast, sulpiride, a dopamine D2 receptor specific antagonist, and risperidone, a serotonin 5-HT2 and dopamine D2 receptor antagonist, did not show effects similar to aripiprazole. The attenuation effect of aripiprazole was blocked by pretreatment with the specific serotonin 5-HT1A antagonist WAY100635. These results of aripiprazole suggest that the attenuation effect of aripiprazole was mediated by 5-HT1A receptors and imply that aripiprazole may have therapeutic value in treating drug-induced psychosis and schizophrenia.

Measurement of antibodies to gastrointestinal nematodes and liver fluke in meat juice of beef cattle and associations with carcass parameters.

In an effort to develop non-invasive methods for the diagnosis of Ostertagia ostertagi and Fasciola hepatica infection in beef cattle, this study was undertaken to evaluate antibody-detection ELISAs in meat juice samples and to investigate the associations between test results and carcass parameters. Preliminary tests were carried out to determine optimal working dilutions of meat juice samples. The Pearson correlation coefficients between ELISA results (expressed as ODR) of serum and meat juice samples from 90 to 100 cows were R=0.82 and 0.75 for O. ostertagi and F. hepatica, respectively. Next, an abattoir survey in Belgian Blue suckler cows was performed, analysing meat juice samples from 726 animals in spring and 724 animals in autumn 2008, originating from a total of 480 herds. There was a large variation in the observed O. ostertagi and F. hepatica ODRs and inter-seasonal differences were observed for F. hepatica (spring>autumn), but not for O. ostertagi. The relationships between individual parasite-specific ELISA results and carcass parameters (warm carcass weight, conformation score, fat coverage) were investigated by linear or logistic mixed models with herd as a random effect, while the relationship between herd average ELISA results and herd averaged carcass weight was investigated by linear regression with mean cow age and season as covariates. An increase in individual O. ostertagi ODR over the interquartile range was associated with an increased likelihood by 1.3 of a low conformation score (score E vs. S), but no significant associations were found with other carcass parameters. However, herd mean ELISA results were negatively associated with a decrease in the herd average carcass weight (P=0.001 and P=0.09 for O. ostertagi and F. hepatica, respectively). An increase in the herd mean O. ostertagi or F. hepatica ODR over the interquartile range was associated with a decrease in herd mean carcass weight of 9.1 and 3.4 kg, respectively. The implications of these results and the value of monitoring parasitic infections by analysis of meat juice samples from the abattoir are discussed.

Aripiprazole for the treatment of psychoses in institutionalized patients with Alzheimer dementia: a multicenter, randomized, double-blind, placebo-controlled assessment of three fixed doses.

OBJECTIVE: To assess the efficacy and safety of aripiprazole for psychosis associated with Alzheimer dementia (AD). METHODS: In this double-blind, multicenter study, 487 institutionalized patients with psychosis associated with AD were randomized to placebo or aripiprazole, 2, 5 or 10 mg/day. Primary efficacy assessment was the mean change from baseline to week 10 on the Neuropsychiatric Inventory-Nursing Home (NPI-NH) version Psychosis Subscale score. Secondary measures included NPI-NH Total, Clinical Global Impression-Severity of Illness (CGI-S), Brief Psychiatric Rating Scale (BPRS) Core and Total, and the Cohen-Mansfield Agitation Inventory (CMAI) scores. RESULTS: Aripiprazole 10 mg/day showed significantly greater improvements (mean change [2 x SD]) than placebo on the NPI-NH Psychosis Subscale (-6.87 [8.6] versus -5.13 [10.0]; F = 6.29, df = 1, 422, p = 0.013 by analysis of covariance [ANCOVA]); CGI-S (-0.72 [1.8] versus -0.46 [1.6]; F = 4.68, df = 1, 419, p = 0.031 [ANCOVA]); BPRS Total (-7.12 [18.4] versus -4.17 [21.6]; F = 4.72, df = 1, 399, p = 0.030 [ANCOVA]); BPRS Core (-3.07 [6.9] versus -1.74 [7.8]; F = 7.30, df = 1, 407, p = 0.007 [ANCOVA]); CMAI (-10.96 [22.6] versus -6.64 [28.6]; F = 5.23, df = 1, 410, p = 0.023 [ANCOVA]), and NPI-NH Psychosis response rate (65 versus 50%; chi(2) = 5.52, df = 1, p = 0.019 [CMH]). Aripiprazole 5 mg/day showed significant improvements versus placebo on BPRS and CMAI scores. Aripiprazole 2 mg/day was not efficacious. Cerebrovascular adverse events were reported: aripiprazole 2 mg/day, N = 1; 5 mg/day, N = 2; 10 mg/day, N = 4; placebo, N = 0. No deaths in any group (aripiprazole 2 mg/day, 3%; 5 mg/day, 2%; 10 mg/day, 7%; placebo, 3%) were considered to be treatment-related. CONCLUSION: Aripiprazole 10 mg/day was efficacious and safe for psychosis associated with AD, significantly improving psychotic symptoms, agitation, and clinical global impression. However, clinicians should be aware of the safety considerations of atypical antipsychotic uses in this population.

Biodiversity as both a cause and consequence of resource availability: a study of reciprocal causality in a predator-prey system.

1. One of the oldest questions in ecology is how species diversity in any given trophic level is related to the availability of essential resources that limit biomass (e.g. water, nutrients, light or prey). Researchers have tried to understand this relationship by focusing either on how diversity is influenced by the availability of resources, or alternatively, how resource abundance is influenced by species diversity. These contrasting perspectives have led to a seeming paradox '... is species diversity the cause or the consequence of resources that limit community biomass?' 2. Here we present results of an experiment that show it is possible for species diversity and resource density to exhibit reciprocal causal relationships in the same ecological system. Using a guild of ladybeetle predators and their aphid prey, we manipulated the number of predator species in field enclosures to examine how predator diversity impacts prey population size. At the same time, we manipulated the abundance of aphid prey in discrete habitat patches within each enclosure to determine how smaller-scale spatial variation in resource abundance affects the number of co-occurring predator species. 3. We found that the number of ladybeetle species added to enclosures had a significant impact on aphid population dynamics because interference competition among the predators reduced per capita rates of predation and, in turn, the overall efficiency of the predator guild. At the same time, spatial variation in aphid abundance among smaller habitat patches generated variation in the observed richness of ladybeetles because more species occurred in patches where predators aggregated in response to high aphid density. 4. The results of our experiment demonstrate that it is possible for species diversity to simultaneously be a cause and a consequence of resource density in the same ecological system, and they shed light on how this might occur for groups of mobile consumers that exhibit rapid responses to spatial and temporal variation in their prey.