Amisulpride and olanzapine combination treatment versus each monotherapy in acutely ill patients with schizophrenia in Germany (COMBINE): a double-blind randomised controlled trial

BACKGROUND

Combining antipsychotics is common in schizophrenia treatment, despite evidence-based guidelines generally not recommending such practice. Otherwise, evidence remains inconclusive, especially regarding specific combinations. The trial aimed to test whether a combination of amisulpride plus olanzapine is more effective than either intervention as a monotherapy.

METHODS

A multicentre, 16-week, randomised, double-blind, controlled trial was done at 16 psychiatric in-patient centres throughout Germany. Inclusion criteria were adults aged 18-65 years with non-first episode schizophrenia or schizoaffective disorder and with a Positive and Negative Syndrome Scale (PANSS) total score of at least 70 and at least two items of the positive symptoms subscale rated at least 4. Patients were randomly assigned to receive 16 weeks of treatment with either amisulpride plus olanzapine, amisulpride plus placebo, or olanzapine plus placebo (1:1:1), and block randomisation was stratified by study site. To keep patients and investigators masked throughout the duration of the trial, amisulpride, olanzapine, and placebo were administered as identical capsules. Flexibly dosed monotherapy of oral amisulpride (amisulpride plus placebo, 200-800 mg per day) or olanzapine (olanzapine plus placebo, 5-20 mg per day) was compared with a combination of amisulpride plus olanzapine. The primary outcome was symptom reduction measured by the PANSS total score after 8 weeks, in the modified intention-to-treat population (all patients randomly assigned to an intervention and receiving at least one study drug dose). As determined a priori, group differences were examined by t tests (Bonferroni-Holm-adjustment) followed by pre-planned Bayesian analyses as well as imputation methods based on mixed models to account for missing values and post-hoc ANCOVA adjusting for PANSS baseline scores. The study was registered on ClinicalTrials.gov, NCT01609153; the German Clinical Trials Register, DRKS00003603; and the European Union Drug Regulating Authorities Clinical Trials Database, EudraCT-No. 2011-002463-20.

FINDINGS

Between June 15, 2012, and Dec 15, 2018, 13 692 patients were assessed for eligibility. 13 364 patients were excluded (including for not meeting inclusion criteria, declining to participate, or inappropriate reasons for changing pharmacological treatment), and 328 were then randomly assigned to an intervention group. 112 patients were randomly assigned to receive amisulpride plus olanzapine, 109 were randomly assigned to receive amisulpride plus placebo, and 107 were randomly assigned to receive olanzapine plus placebo. 321 patients were analysed for the primary outcome in the modified intention-to-treat population after exclusion of screening failures and patients who did not receive the intervention (110 for amisulpride plus olanzapine, 109 for amisulpride plus placebo, and 102 for olanzapine plus placebo). Among the 321 patients who were randomly assigned to intervention groups and analysed for the primary outcome, 229 (71%) were male, 92 (29%) were female; the mean age was 40·2 years (SD 11·7); and 296 (92%) were White and 25 (8%) were classified as other ethnicity. PANSS total score improved significantly more at 8 weeks in the amisulpride plus olanzapine group (-29·6 [SD 14·5]) than in the olanzapine plus placebo group (-24·1 [13·4], p=0·049, Cohen's d=0·396). A significant difference was not observed in reduction of PANSS total score between the amisulpride and olanzapine group compared with the amisulpride and placebo group (-25·2 [SD 15·9], p=0·095, Cohen's d=0·29). After 8 weeks and 16 weeks, sexual dysfunction, weight, and waist circumference increase were significantly higher for patients receiving amisulpride plus olanzapine than for those receiving amisulpride plus placebo, with no differences in serious adverse events. Two patients died during study participation; one randomly assigned to the amisulpride plus olanzapine group, and one assigned to the olanzapine plus placebo group (both assessed with no relation to treatment).

INTERPRETATION

The advantages of amisulpride plus olanzapine have to be weighed against a higher propensity for side-effects. The use of this specific combination therapy could be an alternative to monotherapy in certain clinical situations, but side-effects should be considered.

FUNDING

German Federal Ministry of Education and Research.

Enhancing neuroimaging genetics through meta-analysis for Tourette syndrome (ENIGMA-TS): A worldwide platform for collaboration

Tourette syndrome (TS) is characterized by multiple motor and vocal tics, and high-comorbidity rates with other neuropsychiatric disorders. Obsessive compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), autism spectrum disorders (ASDs), major depressive disorder (MDD), and anxiety disorders (AXDs) are among the most prevalent TS comorbidities. To date, studies on TS brain structure and function have been limited in size with efforts mostly fragmented. This leads to low-statistical power, discordant results due to differences in approaches, and hinders the ability to stratify patients according to clinical parameters and investigate comorbidity patterns. Here, we present the scientific premise, perspectives, and key goals that have motivated the establishment of the Enhancing Neuroimaging Genetics through Meta-Analysis for TS (ENIGMA-TS) working group. The ENIGMA-TS working group is an international collaborative effort bringing together a large network of investigators who aim to understand brain structure and function in TS and dissect the underlying neurobiology that leads to observed comorbidity patterns and clinical heterogeneity. Previously collected TS neuroimaging data will be analyzed jointly and integrated with TS genomic data, as well as equivalently large and already existing studies of highly comorbid OCD, ADHD, ASD, MDD, and AXD. Our work highlights the power of collaborative efforts and transdiagnostic approaches, and points to the existence of different TS subtypes. ENIGMA-TS will offer large-scale, high-powered studies that will lead to important insights toward understanding brain structure and function and genetic effects in TS and related disorders, and the identification of biomarkers that could help inform improved clinical practice.

A meta-analysis on shared and distinct neural correlates of the decision-making underlying altruistic and retaliatory punishment

Individuals who violate social norms will most likely face social punishment sanctions. Those sanctions are based on different motivation aspects, depending on the context. Altruistic punishment occurs if punishment aims to re‐establish the social norms even at cost for the punisher. Retaliatory punishment is driven by anger or spite and aims to harm the other. While neuroimaging research highlighted the neural networks supporting decision‐making in both types of punishment in isolation, it remains unclear whether they rely on the same or distinct neural systems. We ran an activation likelihood estimation meta‐analysis on functional magnetic resonance imaging data on 24 altruistic and 19 retaliatory punishment studies to investigate the neural correlates of decision‐making underlying social punishment and whether altruistic and retaliatory punishments share similar brain networks. Social punishment reliably activated the bilateral insula, inferior frontal gyrus, midcingulate cortex (MCC), and superior and medial frontal gyri. This network largely overlapped with activation clusters found for altruistic punishment. However, retaliatory punishment revealed only one cluster in a posterior part of the MCC, which was not recruited in altruistic punishment. Our results support previous models on social punishment and highlight differential involvement of the MCC in altruistic and retaliatory punishments, reflecting the underlying different motivations.

Pharmacokinetic correlates of venlafaxine: associated adverse reactions

To address the potential correlation between plasma concentrations of venlafaxine (VEN), its active metabolite O-desmethylvenlafaxine (ODVEN) and the active moiety, AM, (ODVEN + VEN) and adverse drug reactions (ADR) in a large naturalistic sample of in- and outpatients. We compared plasma concentrations of VEN, ODVEN and AM and dose-adjusted (C/D) levels as well the ODVEN/VEN ratios between patients complaining ADRs, following the Udvalg for Kliniske Undersogelser side effect rating scales (UKU) (n = 114) and patients without ADRs (control group, n = 688) out of a naturalistic database. We also investigated potential pharmacokinetic correlates of the four UKU categories by comparing patients complaining ADRs with those who did not. Based on previous literature we applied different ODVEN/VEN ratio values as cut-offs to split our sample into two groups at a time and compare frequencies of ADRs between the groups. No differences for demographic and pharmacokinetic variables including plasma and C/D concentrations as well as ODVEN/VEN ratios were observed between study groups. Neither the comparisons between females and males nor between elderly and non-elderly patients revealed significant differences (p > 0.05 in all cases). No differences were also reported exploring the patients complaining ADRs from the 4 UKU categories separately. After applying various ODVEN/VEN cut-offs, groups did not display differences in frequencies of ADRs (p > 0.05 in all cases). Our findings do not demonstrate a direct link between venlafaxine metabolism measures and ADRs. Therefore, additional dimensions are needed to be considered in future trials aiming to disentangle the involved aspects of ADRs in patients receiving venlafaxine.

Duloxetine enters the brain - But why is it not found in the cerebrospinal fluid

BACKGROUND

Antidepressants enter the brain to reach their site of action in a different extent. However, there has been no study to date about duloxetine's ability to enter the brain and cerebrospinal fluid. Aim of this study was to measure blood and cerebrospinal fluid concentrations of duloxetine and to account for the distribution between the two compartments.

METHODS

Concentrations of duloxetine were measured in blood serum and cerebrospinal fluid of 19 patients treated with daily doses of 30-120mg. Daily doses were correlated with serum and cerebrospinal fluid concentrations and serum concentrations were correlated with concentrations in cerebrospinal fluid.

RESULTS

Serum concentrations of duloxetine showed a moderate but significant correlation with the applied daily dose, r=+0.473, p=0.04. Duloxetine concentrations in the cerebrospinal fluid above the designated limit of quantification of 2.0ng/mL were only found in three of the 19 patients.

CONCLUSIONS AND LIMITATIONS

Contrasting to own preceding studies on venlafaxine, mirtazapine and citalopram with comparably high concentrations in cerebrospinal fluid, the here presented findings indicate that duloxetine shows a very different distribution pattern. Very low concentrations in the cerebrospinal fluid may be due to the fact that the drug crosses the blood-cerebrospinal fluid barrier much worse than other antidepressants do, suggesting a low ability of duloxetine to enter the brain. Alternatively, low drug concentrations may be interpreted in a sense of a missing residence time in cerebrospinal fluid due to active transport mechanisms out of this environment either back into the bloodstream or into the brain.

Distribution pattern of mirtazapine and normirtazapine in blood and CSF

RATIONALE

The aim of this study was to investigate the distribution pattern of mirtazapine and its metabolite normirtazapine (N-desmethylmirtazapine) in blood and cerebrospinal fluid (CSF).

OBJECTIVES AND METHODS

Concentrations of mirtazapine were measured in blood serum and CSF of 16 patients treated with daily doses of 7.5-60 mg. Daily doses were correlated with serum and CSF concentrations as well as serum levels with those in CSF.

RESULTS

Serum levels of mirtazapine and normirtazapine showed a strong relation to the daily dose of mirtazapine of r = +0.631 and r = +0.732, respectively (p < 0.01). Between the daily doses and the CSF levels of both mirtazapine and normirtazapine, we only found a trend-wise correlation (r = +0.535, p = 0.060). The correlation between mirtazapine and normirtazapine in serum and CSF was highly significant (r = +0.664, p = 0.005 and r = +0.885, p < 0.001, respectively). High discrepancies between (total) mirtazapine levels in serum and CSF indicate a low penetration into CSF with regard to the total serum concentration as the mean of the calculated penetration ratio was 0.16 (SD = 0.11). By correcting the penetration ratio for the plasma protein binding, the mean CSF/serum ratio for the unbound fraction was 1.05 (SD 0.72, range 0.56-3.19) indicating a high passage into CSF.

CONCLUSIONS

Findings indicate a good ability of mirtazapine and normirtazapine to overcome the blood-cerebrospinal fluid barrier and suggest a high ability to enter the brain with sufficient drug levels at the target sites within the brain contributing to clinical efficacy.

Venlafaxine and O-desmethylvenlafaxine concentrations in plasma and cerebrospinal fluid

OBJECTIVE

To investigate whether drug concentrations of venlafaxine and its metabolite O-desmethylvenlafaxine in plasma can be considered as a surrogate marker of concentrations in brain/cerebrospinal fluid (CSF).

METHOD

For therapeutic drug monitoring purposes, plasma and CSF concentrations of venlafaxine and O-desmethylvenlafaxine were measured between November 2011 and August 2013 in 16 depressive inpatients (ICD-10 diagnoses) who were treated with daily doses of venlafaxine extended release (dose range, 75-225 mg). Daily doses were correlated with plasma and CSF levels. The correlation between venlafaxine, O-desmethylvenlafaxine, and the active moiety (AM) in plasma and CSF was calculated.

RESULTS

Venlafaxine in plasma (P = .005) and CSF (P = .023) correlated significantly with the daily dose, while O-desmethylvenlafaxine and the active moiety (AM = venlafaxine + O-desmethylvenlafaxine) did not. The correlation between venlafaxine, O-desmethylvenlafaxine, and the AM in plasma and CSF was highly significant (P < .001). The calculated CSF/plasma ratio was 0.74 for venlafaxine, 0.88 for O-desmethylvenlafaxine, and 0.84 for the AM.

CONCLUSIONS

Venlafaxine and O-desmethylvenlafaxine were found to penetrate well into CSF in patients, which indicated good availability of the drug in the brain, although the findings on CSF concentrations do not allow calculation of concentrations at the target structure within the brain. CSF/plasma ratios for venlafaxine and its metabolite were high probably due to low plasma protein binding. The poor correlation of dose to concentrations in body fluids and the highly significant correlation of plasma to CSF concentrations indicate that plasma concentration is a much better marker of drug concentration in brain than the dose.

Effects of psychotropic drugs on brain plasticity in humans

Although neurotransmitter-based hypotheses still prevail current thinking about the mechanism of action of psychotropic drugs, recent insight into the pathophysiology of psychiatric disorders has unveiled a range of new therapeutic actions of the drugs used to treat those disorders. Especially antidepressants seem to exert at least some of their effects via restoration of synaptic/neuronal plasticity. In addition, there is increasing evidence that several of the second-generation antipsychotics and some anticonvulsants affect neuronal survival/apoptosis as well as synaptic plasticity. Most of this evidence stems from work in animals. In this review, we will focus on the evidence for neuroplastic effects of psychotropic drugs in humans being aware of the fact that most of the data are derived from animals and that volumetric studies in humans can only indicate structural plasticity and not necessarily functional plasticity. However, as the data from human studies are rather poor and inconclusive, and sometimes even conflicting, it seems impossible to draw general conclusions. Until now studies on neuroplasticity in humans can only explain small pieces of the effects of psychotropic drugs on brain plasticity in humans. Nevertheless, future prospects for the development of new drugs targeting brain plasticity will be of importance and will complete this overview.

Effects of antipsychotic treatment on cognition in healthy subjects

Cognitive impairments can be observed in the majority of diseases with disturbed dopamine transmission. They are considered as core symptoms of schizophrenia, a disorder in which they appear to be particularly pronounced. Their neurobiological background is not yet sufficiently investigated, but dopaminergic systems are believed to play a crucial role. The aim of this single-blind, randomised, placebo-controlled study was to examine the effects of subchronic antidopaminergic treatment on cognitive functions in healthy subjects. In total, 72 healthy volunteers, randomised into four groups, received one antidopaminergic substance (aripiprazole, haloperidol or reserpine) or placebo, respectively, for 7 days. A comprehensive neurocognitive assessment was conducted at baseline, 24 h after the last medication intake and 7 days later. In the Digit Symbol Substitution Test a distinct, statistically significant improvement was measured in the second session in the placebo but not in the medication group. A significant group*time interaction for reaction times in three subtests of the Test battery for Attentional Performance (TAP) was also found. Our findings indicate that modulation of dopaminergic systems affects primarily speed of information processing, attention and learning. Absence of effects on other functions, differing from previous reports, may be an expression of a sufficient counter-regulation.

Brain and plasma pharmacokinetics of aripiprazole in patients with schizophrenia: an [18F]fallypride PET study

OBJECTIVE

Aripiprazole at clinically effective doses occupies some 90% of striatal dopamine 2 and 3 (D(2)/D(3)) receptors. In order to further characterize its extrastriatal and time-dependent binding characteristics, the authors conducted positron emission tomography (PET) studies with the D(2)/D(3) antagonist [(18)F]fallypride at varying time points after the last aripiprazole administration in patients with schizophrenia.

METHOD

Sixteen inpatients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder receiving treatment with aripiprazole underwent an [(18)F]fallypride PET scan. Receptor occupancy was calculated as the percentage reduction in binding potential relative to unblocked values measured in eight age-matched, medication-free patients with schizophrenia. In addition, aripiprazole serum concentrations were determined as part of a routine therapeutic drug monitoring program in a large group of patients (N=128) treated with aripiprazole.

RESULTS

Mean dopamine D(2)/D(3) receptor occupancy was high in all brain regions investigated, with no binding difference across brain regions. Nonlinear regression analysis revealed maximum attainable receptor occupancy (E(max)) values close to saturation. The values for serum concentration predicted to provide 50% of E(max) (EC(50)) were in the range of 5-10 ng/ml in all brain regions. The D(2)/D(3) receptors were completely saturated when serum aripiprazole concentration exceeded 100-150 ng/ml. The mean concentration in the large clinical patient sample was 228 ng/ml (SD=142).

CONCLUSIONS

Because of its high affinity for D(2)/D(3) receptors and its long elimination half-life, aripiprazole at clinical doses occupies a high fraction of its target receptor everywhere in the brain. Its dissociation from those receptors is very slow, such that the authors calculate from the results that in patients with serum aripiprazole concentrations in the range typical for clinical practice, D(2)/D(3) receptors must remain nearly saturated for as long as 1 week after the last dose.