Striatal and extrastriatal dopamine D2 receptor occupancy by a novel antipsychotic, blonanserin: a PET study with [11C]raclopride and [11C]FLB 457 in schizophrenia

Optimisation of pharmacotherapy in psychiatry through therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests: Focus on antipsychotics

BACKGROUND

For psychotic disorders (i.e. schizophrenia), pharmacotherapy plays a key role in controlling acute and long-term symptoms. To find the optimal individual dose and dosage strategy, specialised tools are used. Three tools have been proven useful to personalise drug treatments: therapeutic drug monitoring (TDM) of drug levels, pharmacogenetic testing (PG), and molecular neuroimaging.

METHODS

In these Guidelines, we provide an in-depth review of pharmacokinetics, pharmacodynamics, and pharmacogenetics for 45 antipsychotics. Over 30 international experts in psychiatry selected studies that have measured drug concentrations in the blood (TDM), gene polymorphisms of enzymes involved in drug metabolism, or receptor/transporter occupancies in the brain (positron emission tomography (PET)).

RESULTS

Study results strongly support the use of TDM and the cytochrome P450 (CYP) genotyping and/or phenotyping to guide drug therapies. Evidence-based target ranges are available for titrating drug doses that are often supported by PET findings.

CONCLUSION

All three tools discussed in these Guidelines are essential for drug treatment. TDM goes well beyond typical indications such as unclear compliance and polypharmacy. Despite its enormous potential to optimise treatment effects, minimise side effects and ultimately reduce the global burden of diseases, personalised drug treatment has not yet become the standard of care in psychiatry.

Recent applications of positron emission tomographic (PET) imaging in psychiatric drug discovery

INTRODUCTION

Psychiatry is one of the medical disciplines that suffers most from a lack of innovation in its therapeutic arsenal. Many failures in drug candidate trials can be explained by pharmacological properties that have been poorly assessed upstream, in terms of brain passage, brain target binding and clinical outcomes. Positron emission tomography can provide pharmacokinetic and pharmacodynamic data to help select candidate-molecules for further clinical trials.

AREAS COVERED

This review aims to explain and discuss the various methods using positron-emitting radiolabeled molecules to trace the cerebral distribution of the drug-candidate or indirectly measure binding to its therapeutic target. More than an exhaustive review of PET studies in psychopharmacology, this article highlights the contributions this technology can make in drug discovery applied to psychiatry.

EXPERT OPINION

PET neuroimaging is the only technological approach that can, in vivo in humans, measure cerebral delivery of a drug candidate, percentage and duration of target binding, and even the pharmacological effects. PET studies in a small number of subjects in the early stages of the development of a psychotropic drug can therefore provide the pharmacokinetic/pharmacodynamic data required for subsequent clinical evaluation. While PET technology is demanding in terms of radiochemical, radiopharmacological and nuclear medicine expertise, its integration into the development process of new drugs for psychiatry has great added value.

Safety and effectiveness of oral medium to high dose blonanserin in patients with schizophrenia: subgroup analysis from a prospective, multicenter, post-marketing surveillance study in mainland China

BACKGROUND

Blonanserin (BNS) had been undergoing post-market surveillance (PMS) since September 2018. Using the surveillance data, we did this analysis to assess the safety and effectiveness of different doses of BNS to explore a sufficient dose range of BNS in Chinese patients with schizophrenia (SZ).

METHODS

A 12-week, prospective, observational, single-arm, multicenter, open-label PMS was conducted. In this analysis, we divided the patients from PMS into low, medium to high, and high dose groups based on the dose of BNS they received, with medium to high dose group being the focus. The Brief Psychiatric Rating Scale (BPRS) scores at week 2 or 4, 6 or 8, and 12 were calculated to evaluate the effectiveness of BNS in improving psychiatric symptoms. The safety of BNS was reported as the incidence of adverse drug reactions.

RESULTS

364 patients were included in the medium to high dose group, of which 321 completed the surveillance, with a dropout rate of 11.8%. The mean daily dose was 15.1 ± 1.92 mg. The BPRS total score was 50.1 ± 11.95 at baseline and decreased to 26.6 ± 7.43 at 12 weeks (P < 0.001). When compared with other groups, the median to high dose group achieved significantly more reduction in BPRS score at week 12 (P = 0.004 versus low dose and P = 0.033 versus higher dose). Extrapyramidal symptoms [EPS (46.4%)] were the most common adverse reactions in the medium to high group. The average weight gain during the surveillance was 0.5 ± 2.56 kg and prolactin elevation occurred in 2.2% patients. Most adverse reactions were mild.

CONCLUSIONS

BNS at medium to high doses (mean 15.1 mg/d) significantly improved symptoms of SZ and was well-tolerated. Most ADRs were mild, and the likelihood of causing metabolic side effects and prolactin elevations was low. Medium to high dose of BNS is a more potent treatment choice for SZ.

TRIAL REGISTRATION NUMBER

ChiCTR2100048734. Date of registration: 2021/07/15 (retrospectively registered).

Effectiveness and safety of blonanserin in young and middle-aged female patients with schizophrenia: data from a post-marketing surveillance

BACKGROUND

A post-marketing surveillance of blonanserin has been ongoing since September 2018. The aim of this study was to assess the effectiveness and safety of oral blonanserin in Chinese young and middle-aged female patients with schizophrenia in real clinical settings, using the data from the post-marketing surveillance.

METHODS

A 12-week, prospective, multi-center, open-label, post-marketing surveillance was conducted. Female patients aged 18-40 years were included in this analysis. The Brief Psychiatric Rating Scale (BPRS) was used to evaluate the effectiveness of blonanserin in improving psychiatric symptoms. The incidence of adverse drug reactions (ADRs) such as of extrapyramidal symptoms (EPS), prolactin elevation and the weight gain were used to evaluate the safety profile of blonanserin.

RESULTS

A total of 392 patients were included both in the safety and full analysis sets, 311 patients completed the surveillance protocol. The BPRS total score was 48.8 ± 14.11 at the baseline, decreasing to 25.5 ± 7.56 at 12 weeks (P < 0.001, compared with baseline). EPS (20.2%) including akathisia, tremor, dystonia, and parkinsonism were found as the most frequent ADRs. The mean weight gain was 0.27 ± 2.5 kg at 12 weeks from the baseline. Four cases (1%) of prolactin elevation were observed during the period of surveillance.

CONCLUSION

Blonanserin significantly improved the symptoms of schizophrenia in female patients aged 18-40 years; the drug was well tolerated and had a low tendency to cause metabolic side effects, including prolactin elevation in these patients. Blonanserin might be a reasonable drug for the treatment of schizophrenia in young and middle-aged female patients.

Prediction of Corresponding Dose of Transdermal Blonanserin to Oral Dose Based on Dopamine D2 Receptor Occupancy: Unique Characteristics of Blonanserin Transdermal Patch

BACKGROUND/PURPOSE

Blonanserin is an atypical antipsychotic, a potent selective antagonist of dopamine D2 receptor (D2), prescribed as oral formulations in patients with schizophrenia. Blonanserin transdermal patch was developed to provide a new treatment option, but the corresponding dose to oral blonanserin was not clear. The aims of this study were to clarify the pharmacokinetic (PK)-pharmacodynamic characteristics of blonanserin after transdermal patch application and to evaluate the corresponding dose to oral formulation based on striatal D2 occupancy.

METHODS

The relationship between D2 occupancy and plasma blonanserin concentration was analyzed using an Emax model based on data from positron emission tomography study with oral and transdermal blonanserin. D2 occupancy was simulated using Emax models based on the observed plasma concentrations and the simulated plasma concentrations obtained from population PK model.

RESULTS

Plasma blonanserin concentration levels after repeated patch applications were nearly stable throughout the day and no effect of sex, advanced age, or application site was detected. The concentration at half maximal D2 occupancy during transdermal patch applications, 0.857 ng/mL, was higher than that after oral doses, 0.112 ng/mL, suggesting metabolite contribution after oral doses. The median predicted D2 occupancy during blonanserin patch applications at doses of 40 and 80 mg/d was 48.7% and 62.5%, respectively, and the distribution of D2 occupancy at these doses could cover most of that at oral doses of 8 to 24 mg/d.

CONCLUSIONS

Predicted D2 occupancy suggested that a 40- to 80-mg/d blonanserin transdermal patch dose corresponds to an 8- to 24-mg/d oral dose for the treatment of schizophrenia.

Effect of DL-Methylephedrine on Dopamine Transporter Using Positron Emission Tomography With [18F]FE-PE2I

RATIONALE

Since ephedrine has a dopamine transporter (DAT) inhibitory effect similar to amphetamine, dl-methylephedrine, a derivative of ephedrine, is considered to have the characteristics of a central nervous system stimulant due to the DAT inhibitory effect. For example, the World Anti-Doping Agency categorizes dl-methylephedrine as a stimulant in the prohibited list for competitions. Assuming to have the same effect as ephedrine, the urinary concentration of dl-methylephedrine is regulated below 10 μg/mL, as is ephedrine. However, the extent to which dl-methylephedrine affects brain function is not yet fully understood.

OBJECTIVES

The purpose of this study was to evaluate DAT occupancy by a single oral administration of a daily dose of dl-methylephedrine using positron emission tomography (PET) with [¹⁸F]FE-PE2I to characterize its stimulatory effect on the central nervous system.

METHODS

Nine healthy male volunteers were enrolled in the study. The experiments were designed as a placebo-controlled randomized double-blind crossover comparative study. After the first PET scan in a drug-free state, the second and third PET scans were performed with randomized dosing at 60 mg of dl-methylephedrine or placebo. The plasma and urine concentrations of dl-methylephedrine were measured just before and after the PET scans, respectively.

RESULTS

Mean urine and plasma concentrations of dl-methylephedrine were 13.9 μg/mL and 215.2 ng/mL, respectively. Mean DAT occupancy in the caudate was 4.4% for dl-methylephedrine and 1.2% for placebo. Mean DAT occupancy in the putamen was 3.6% for dl-methylephedrine and 0.5% for placebo. There was no significant difference of DAT occupancies between the groups.

CONCLUSION

In this study, the urinary concentration of dl-methylephedrine (13.9 μg/mL) was higher than the prohibited reference value (10.0 μg/mL), and there was no significant difference in DAT occupancy between dl-methylephedrine and placebo. These findings suggest that a clinical daily dose of dl-methylephedrine may exceed the doping regulation value according to urine concentration; however, it was considered that at least the central excitatory effect mediated by DAT inhibition was not observed at the daily dose of dl-methylephedrine.

Safety and Effectiveness of Blonanserin in Chinese Patients with Schizophrenia: An Interim Analysis of a 12-Week Open-Label Prospective Multi-Center Post-marketing Surveillance

Schizophrenia is an unexplained, complex and serious mental illness. Blonanserin (BNS) is a new antipsychotic drug widely used in the treatment of schizophrenia. However, large-scale clinical studies have not been conducted in China. A multi-center, prospective, open-label, 12-week surveillance was carried out to evaluate the safety and effectiveness of BNS in patients with schizophrenia in China. Safety assessments included adverse drug reactions (ADRs), extrapyramidal symptoms (EPS), akathisia, concomitant medications for EPS by the end of treatment, and the changes in body weight from baseline by the end of treatment. The effectiveness was evaluated by the Brief Psychiatric Rating Scale (BPRS). From September 2018 to May 2020, of the 1,060 patients enrolled, 1,018 were included in the full analysis set (FAS) and safety set (SS), respectively. ADRs were developed in 205 patients among the included, the incidence being 20.1%. ADRs of EPS occurred in 169 patients, the incidence being 16.6%, ADRs of akathisia occurred in 90 patients, the incidence being 8.8%; concomitant therapeutic and prophylactic agents for EPS accounts for 19.2%; 4.0% of patients had a ≥7% increase in body weight from baseline at 12 weeks after initiating treatment. Using the last-observation-carried-forward (LOCF) method, the changes in total BPRS scores were -11.2 ± 10.17 (N = 1,018), -16.8 ± 12.69 (N = 1,018) and -20.6 ± 13.99 (N = 1,018) after 2/4, 6/8, or 12 weeks, respectively. 53.5% (545/1,018) patients showed response to blonanserin treatment in week 12. The post-marketing surveillance results of BNS demonstrates safety profile and effectiveness of the drug.

Safety and effectiveness of oral blonanserin for schizophrenia: A review of Japanese post-marketing surveillances

Schizophrenia significantly limits social functioning with positive and negative symptoms and cognitive dysfunction. Blonanserin (LONASEN®), a novel second-generation antipsychotic approved for treating schizophrenia in Japan in 2008, reportedly shows beneficial effects on cognitive function as well as positive and negative symptoms, with potential for improving social functioning. To understand the safety and effectiveness of blonanserin in the real clinical practice, five Japanese post-marketing surveillances have been conducted and published to date. In this article, we reviewed all the Japanese post-marketing surveillances and discussed the clinical usefulness of blonanserin in patients with schizophrenia having diverse clinical characteristics. Adverse drug reactions, such as akathisia and extrapyramidal symptoms, were common in all surveillances. However, those specific to second-generation antipsychotics, such as weight gain and abnormalities in glycometabolism or lipid metabolism, were rarely observed. In addition, no adverse drug reactions apart from clinical trial results were found. Brief Psychiatric Rating Scale total scores in all surveillances significantly lowered at the last evaluation than at baseline. These results were consistent through 1-year of treatment, suggesting that effectiveness is maintained even after long-term use. In conclusion, blonanserin is considered a beneficial drug in real clinical practice for patients with schizophrenia having diverse characteristics.

A randomized-controlled trial of blonanserin and olanzapine as adjunct to antipsychotics in the treatment of patients with schizophrenia and dopamine supersensitivity psychosis: The ROADS study

Dopamine supersensitivity psychosis (DSP) is a key factor contributing to the development of antipsychotic treatment-resistant schizophrenia. We examined the efficacy and safety of blonanserin (BNS) and olanzapine (OLZ) as adjuncts to prior antipsychotic treatment in patients with schizophrenia and DSP in a 24-week, multicenter (17 sites), randomized, rater-blinded study with two parallel groups (BNS and OLZ add-on treatments) in patients with schizophrenia and DSP: the ROADS Study. The primary outcome was the change in the Positive and Negative Syndrome Scale (PANSS) total score from baseline to week 24. Secondary outcomes were changes in the PANSS subscale scores, Clinical Global Impressions, and Extrapyramidal Symptom Rating Scale (ESRS), and changes in antipsychotic doses. The 61 assessed patients were allocated into a BNS group (n = 26) and an OLZ group (n = 29). The PANSS total scores were reduced in both groups (mean ± SD: -14.8 ± 24.0, p = 0.0042; -10.5 ± 12.9, p = 0.0003; respectively) with no significant between-group difference (mean, -4.3, 95 %CI 15.1-6.4, p = 0.42). The BNS group showed significant reductions from week 4; the OLZ group showed significant reductions from week 8. The ESRS scores were reduced in the BNS group and the others were reduced in both groups. The antipsychotic monotherapy rates at the endpoint were 26.3 % (n = 6) for BNS and 23.8 % (n = 5) for OLZ. The concomitant antipsychotic doses were reduced in both groups with good tolerability. Our results suggest that augmentations with BNS and OLZ are antipsychotic treatment options for DSP patients, and BNS may be favorable for DSP based on the relatively quick responses to BNS observed herein.

Striatal Dopamine D2 Receptor Occupancy Induced by Daily Application of Blonanserin Transdermal Patches: Phase II Study in Japanese Patients With Schizophrenia

BACKGROUND

Transdermal antipsychotic patch formulations offer potential benefits, including improved adherence. This study investigated the striatal dopamine D2 receptor occupancy with daily blonanserin transdermal patch application.

METHODS

This open-label, phase II study enrolled 18 Japanese outpatients (20 to <65 years) with schizophrenia (DSM-IV-TR criteria; total Positive and Negative Syndrome Scale score <120 at screening) treated with blonanserin 8-mg or 16-mg tablets. Patients continued tablets for 2-4 weeks at their current dose and were then assigned to once-daily blonanserin patches (10/20/40/60/80 mg daily) for 2-4 weeks based on the oral dose. [11C]raclopride positron emission tomography scanning determined blonanserin striatal dopamine D2 receptor occupancy (primary endpoint). Secondary endpoints included assessment of receptor occupancy by dose, changes in Positive and Negative Syndrome Scale and Clinical Global Impressions-Severity of Illness-Severity scores, patient attitudes towards adherence, and patch adhesiveness.

RESULTS

Of 18 patients who started the blonanserin tablet treatment period, 14 patients completed treatment. Mean D2 receptor occupancy for blonanserin tablets 8 mg/d (59.2%, n = 5) and 16 mg/d (66.3%, n = 9) was within the values for blonanserin patches: 10 mg/d (33.3%, n = 3), 20 mg/d (29.9%, n = 2), 40 mg/d (61.2%, n = 3), 60 mg/d (59.0%, n = 3), and 80 mg/d (69.9%, n = 3). Occupancy generally increased with increasing blonanserin dose for both formulations with the half maximal receptor occupancy for tablets and patches associated with doses of 6.9 mg/d and 31.9 mg/d, respectively. Diurnal variability in occupancy was lower during transdermal patch treatment than during tablet treatment. Blonanserin transdermal patches were well tolerated with no major safety concerns.

CONCLUSIONS

Blonanserin patches (40/80 mg/d) have lower diurnal variability in occupancy than blonanserin tablets (8/16 mg/d), and patches at doses of 40 mg/d and 80 mg/d appear to be a suitable alternative for blonanserin tablets at doses of 8 mg/d and 16 mg/d, respectively. Blonanserin patches represent a potential new treatment option for patients with schizophrenia.

TRIAL REGISTRY

JAPIC Clinical Trials Information registry (www.clinicaltrials.jp; JapicCTI-No: JapicCTI-121914).

PET technology for drug development in psychiatry

Positron emission tomography (PET) is a non‐invasive imaging method to measure the molecule in vivo. PET imaging can evaluate the central nervous system drugs as target engagement in the human brain. For antipsychotic drugs, adequate dopamine D2 receptor occupancy (“therapeutic window”) is reported to be from 65%‐70% to 80% to achieve the antipsychotic effect without extrapyramidal symptoms. For antidepressants, the clinical threshold of serotonin transporter (5‐HTT) occupancy is reported to be 70%‐80% although the relation between the side effect and 5‐HTT occupancy has not yet been established. Evaluation of norepinephrine transporter (NET) occupancy for antidepressant is ongoing as adequate PET radioligands for NET were developed recently. Measurement of the target occupancy has been a key element to evaluate the in vivo target engagement of the drugs. In order to evaluate new drug targets for disease conditions such as negative symptoms/cognitive impairment of schizophrenia and treatment‐resistant depression, new PET radioligands need to be developed concurrently with the drug development.

PET imaging can evaluate the central nervous system drugs as target engagement in the human brain. The uptake of [¹¹C]raclopride for dopamine D2 receptors decreased from (A) baseline to (B) antipsychotic administration conditions.

Model-based analysis of therapeutic efficacy of blonanserin and risperidone in schizophrenia patients and effects on prolactin: A randomized double-blind study

This study examined randomized controlled trial data for blonanserin and risperidone in Chinese schizophrenia patients (N = 264). Data related to historical changes in the Positive and Negative Syndrome Scale (PANSS) were used to successfully construct a longitudinal E_max model. Results: (a) The efficacy of the two drugs was similar after week 8, showing a small difference in PANSS reduction. (b) Using the model, we predicted that each 5-point increase in the baseline FPOS (positive score in PANSS five-factor subscales) leads to a decrease in the PANSS total scores at week 8 for 2 points in patients administered blonanserin. (c) The effect of blonanserin on prolactin (PRL) elevation was less. The model was used to predict that prolactin elevations in patients administered risperidone were 2.41-fold of those in patients administered blonanserin. (d) Model quantitation showed that gender is a risk factor for prolactin elevation. Prolactin elevations in female patients were 2.95-fold of the value in male patients administered the same drug. The model demonstrated Blonanserin has similar antischizophrenic efficacy and less serum prolactin rising compared to risperidone in Chinese patients.

Switching Antipsychotics to Blonanserin in Patients with Schizophrenia: An Open-label, Prospective, Multicenter Study

Objective

This study was performed to investigate the efficacy and tolerability of blonanserin in schizophrenic patients who were previously treated with other antipsychotics but, due to insufficient response, were switched to blonanserin.

Methods

A total of 52 patients with schizophrenia who were unresponsive to treatment with antipsychotic monotherapy or combination therapy were recruited into this 12-week, open-label, prospective, multicenter study. Patients were switched to blonanserin from their existing antipsychotics over a maximum 2-week tapering-off period. Efficacy was primarily evaluated using the 18-item Brief Psychiatric Rating Scale (BPRS). Assessments were performed at baseline, and at weeks 1, 2, 4, 8, and 12.

Results

Switching to blonanserin resulted in a significant decrease in the mean total score on the BPRS from baseline (56.8 ± 9.4) to week 12 (42.1 ± 13.8, p < 0.001). The most common adverse events were extrapyramidal symptoms (n = 12, 23.1%), insomnia (n = 10, 19.2%), and emotional arousal (n = 6, 11.5%). Overweight or obese patients (body mass index ≥ 23 kg/m², n = 33) who switched to blonanserin exhibited significant weight loss from 75.2 ± 9.3 kg at baseline to 73.5 ± 9.2 kg at week 12 (p = 0.006). The total cholesterol (baseline, 236.1 ± 47.6 mg/dl; endpoint [week 12], 209.9 ± 28.0 mg/dl; p = 0.005) and prolactin levels (baseline, 80.0 ± 85.2 ng/ml; endpoint [week 12], 63.2 ± 88.9 ng/ml; p = 0.003) were also significantly improved in patients with hypercholesterolemia or hyperprolactinemia.

Conclusion

The results of the present study suggest that switching to blonanserin may be an effective strategy for schizophrenic patients unresponsive to other antipsychotic treatments.

Comparison of Dopamine D3 and D2 Receptor Occupancies by a Single Dose of Blonanserin in Healthy Subjects: A Positron Emission Tomography Study With [11C]-(+)-PHNO

BACKGROUND

Blockade of D3 receptor, a member of the dopamine D2-like receptor family, has been suggested as a possible medication for schizophrenia. Blonanserin has high affinity in vitro for D3 as well as D2 receptors. We investigated whether a single dose of 12 mg blonanserin, which was within the daily clinical dose range (i.e., 8-24 mg) for the treatment of schizophrenia, occupies D3 as well as D2 receptors in healthy subjects.

METHODS

Six healthy males (mean 35.7±7.6 years) received 2 positron emission tomography scans, the first prior to taking blonanserin, and the second 2 hours after the administration of a single dose of 12 mg blonanserin. Dopamine receptor occupancies by blonanserin were evaluated by [11C]-(+)-PHNO.

RESULTS

Occupancy of each region by 12 mg blonanserin was: caudate (range 64.3%-81.5%; mean±SD, 74.3±5.6%), putamen (range 60.4%-84.3%; mean±SD, 73.3%±8.2%), ventral striatum (range 40.1%-88.2%; mean±SD, 60.8%±17.1%), globus pallidus (range 65.8%-87.6%; mean±SD, 75.7%±8.6%), and substantia nigra (range 56.0%-88.7%; mean±SD, 72.4%±11.0%). Correlation analysis between plasma concentration of blonanserin and receptor occupancy in D2-rich (caudate and putamen) and D3-rich (globus pallidus and substantia nigra) regions showed that EC50 for D2-rich region was 0.39 ng/mL (r=0.43) and EC50 for D3-rich region was 0.40 ng/mL (r=0.79).

CONCLUSIONS

A single dose of 12 mg blonanserin occupied D3 receptor to the same degree as D2 receptor in vivo. Our results were consistent with previous studies that reported that some of the pharmacological effect of blonanserin is mediated via D3 receptor antagonism.

Quantitative positron emission tomography in brain research

The application of positron emission tomography (PET) in brain research has increased substantially during the past 20years, and is still growing. PET provides a unique insight into physiological and pathological processes in vivo. In this article we introduce the fundamentals of PET, and the methods available for acquiring quantitative estimates of the parameters of interest. A short introduction to different areas of application is also given, including basic research of brain function and in neurology, psychiatry, drug receptor occupancy studies, and its application in diagnostics of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Our aim is to inform the unfamiliar reader of the underlying basics and potential applications of PET, hoping to inspire the reader into considering how the technique could be of benefit for his or her own research.

Longer Telomere Length of T lymphocytes in Patients with Early and Chronic Psychosis

Objective

To investigate pathological conditions that act as sources of pro-inflammatory cytokines and cytotoxic substances to examine telomere length (TL) in patients with either early (duration of illness [DI] ≤5 years) or chronic (DI >5 years) psychosis using T lymphocytes.

Methods

Based on these factors and the important role that T lymphocytes play in inflammation, the present study measured the TL of T lymphocytes in patients with either early or chronic psychosis. Additionally, smoking, metabolic syndrome, depression, and cognitive functioning were assessed to control for confounding effects.

Results

TL was significantly longer in patients with early and chronic psychosis than in healthy control subjects and, moreover, the significance of these findings remained after controlling for age, smoking, metabolic syndrome, DI, chlorpromazine-equivalent dose, and cognitive functioning (F=9.57, degree of freedom=2, p<0.001). Additionally, the DI, chlorpromazine-equivalent doses, and the five-factor scores of the Positive and Negative Syndrome Scale were not significantly correlated with the TL of T lymphocytes in either all patients or each psychosis group.

Conclusion

Possible mechanisms underlying the effects of antipsychotic medications on telomerase are discussed in the present study, but further studies measuring both telomerase activity and TL using a prospective design will be required.

Effectiveness of blonanserin for patients with drug treatment-resistant schizophrenia and dopamine supersensitivity: A retrospective analysis

OBJECTIVE

Dopamine supersensitivity psychosis (DSP) is one of the key factors contributing to the development of antipsychotic treatment-resistant schizophrenia (TRS). We investigated the efficacy of blonanserin, an atypical antipsychotic, for patients with TRS and DSP.

METHODS

In this 12-month retrospective follow-up study, we investigated the cases of eight consecutive patients with unstable TRS and DSP treated with blonanserin as an add-on therapy. We examined changes in scores for the Brief Psychiatric Rating Scale (BPRS), Clinical Global Impression-Severity of Illness (CGI-S) scale and the Global Assessment of Functioning scale (GAF) during the 12 months after the administration of blonanserin.

RESULTS

The patients' total scores on the BPRS and GAF scores were significantly improved by 3 months at the latest. Positive BPRS and CGI-S scores were also improved by 6 months at the latest. The total chlorpromazine-equivalent doses of antipsychotics were significantly reduced from 1462.3±499.6mg to 794.1±642.8mg (p=0.001) after 12 months of blonanserin treatment, with a favorable safety and tolerability profile.

CONCLUSIONS

Blonanserin may be a promising antipsychotic for the treatment of TRS and DSP.

Comparative study of the efficacy and safety between blonanserin and risperidone for the treatment of schizophrenia in Chinese patients: A double-blind, parallel-group multicenter randomized trial

This randomized, double-blind study compared the efficacy and safety of blonanserin and risperidone to treat Chinese schizophrenia patients aged ≥18 and < 65 years. Patients with Positive and Negative Syndrome Scale (PANSS) total scores ≥70 and ≤ 120 were randomized to receive blonanserin or risperidone using a gradual dose-titration method (blonanserin tablets: 8-24 mg/day; risperidone tablets: 2-6 mg/day), twice daily. Treatment populations consisted of 128 blonanserin-treated patients and 133 risperidone-treated patients. Intention-to-treat analysis was performed using the last observation carried forward method. Reductions of PANSS total scores by blonanserin and risperidone treatment were -30.59 and -33.56, respectively. Risperidone treatment was associated with elevated levels of serum prolactin (67.16% risperidone versus 52.31% blonanserin) and cardiac-related abnormalities (22.39% risperidone versus 12.31% blonanserin), and blonanserin patients were more prone to extrapyramidal side effects (48.46% blonanserin versus 29.10% risperidone). In conclusion, blonanserin was as effective as risperidone for the treatment of Chinese patients with schizophrenia. The overall safety profiles of these drugs are comparable, although blonanserin was associated with a higher incidence of EPS and risperidone was associated with a higher incidence of prolactin elevation and weight gain. Thus, blonanserin is useful for the treatment of Chinese schizophrenia patients.

Antipsychotic dosing: found in translation

In the field of schizophrenia research, as in other areas of psychiatry, there is a sense of frustration that greater advances have not been made over the years, calling into question existing research strategies. Arguably, many purported gains claimed by research have been "lost in translation," resulting in limited impact on diagnosis and treatment in the clinical setting. There are exceptions; for example, we would argue that different lines of preclinical and clinical research have substantially altered how we look at antipsychotic dosing. While this story remains a work in progress, advances "found in translation" have played an important role. Detailing these changes, the present paper speaks to a body of evidence that has already shifted clinical practice and raises questions that may further alter the manner in which antipsychotics have been administered over the last 6 decades.

In vivo activity of modafinil on dopamine transporter measured with positron emission tomography and [¹⁸F]FE-PE2I

Modafinil, a wake-promoting drug used to treat narcolepsy, is a dopamine transporter inhibitor and is said to have very low abuse liability; this, however, is still up for debate. We conducted a dopamine transporter (DAT) occupancy study with modafinil (200 or 300 mg) in ten healthy volunteers using positron emission tomography (PET) with [¹⁸F]FE-PE2I, a new PET radioligand with high affinity and selectivity for the dopamine transporter, to characterize its relation to abuse liability. Mean striatal DAT occupancies were 51.4% at 200 mg and 56.9% at 300 mg. There was a significant correlation between occupancy and plasma concentration, indicating dose dependency of DAT inhibition by modafinil in the striatum, and especially in the nucleus accumbens. This study showed that DAT occupancy by modafinil was close to that of methylphenidate, indicating that modafinil may be near the same level as methylphenidate in relation to abuse liability in terms of dopaminergic transmission.

Switching antipsychotics to aripiprazole or blonanserin and plasma monoamine metabolites levels in patients with schizophrenia

OBJECTIVE

Blonanserin is a novel atypical antipsychotic drug that has efficacy equal to risperidone. We investigated the effects of aripiprazole and blonanserin on clinical symptoms and plasma levels of homovanillic acid (pHVA) and 3-methoxy-4hydroxyphenylglycol in the switching strategy of schizophrenia.

METHODS

Twenty two Japanese patients with schizophrenia were enrolled into this open study. The antipsychotics of all patients were switched to aripiprazole or blonanserin for the improvement of clinical symptoms or side effects. Plasma monoamine metabolites levels were analyzed with high-performance liquid chromatography.

RESULTS

There were no significant effects for time (p = 0.346) or time × group interaction (p = 0.27) on the changes of positive and negative syndrome scale (PANSS) total score, although blonanserin decreased PANSS scores. We observed negative correlation between pHVA at baseline and the change in PANSS total score (rs = -0.450, p = 0.046). We also found positive correlation between the changes in pHVA and the changes in PANSS total (rs = 0.536, p = 0.015) and positive (rs = 0.572, p = 0.008) scores.

CONCLUSIONS

There were no differences between blonanserin and aripiprazole in the improvement of clinical symptoms. Our results suggest that pHVA may be useful indicator for the switching strategy to aripiprazole or blonanserin in schizophrenia.

Biomarker investigations related to pathophysiological pathways in schizophrenia and psychosis

Post-mortem brain investigations of schizophrenia have generated swathes of data in the last few decades implicating candidate genes and protein. However, the relation of these findings to peripheral biomarker indicators and symptomatology remain to be elucidated. While biomarkers for disease do not have to be involved with underlying pathophysiology and may be largely indicative of diagnosis or prognosis, the ideal may be a biomarker that is involved in underlying disease processes and which is therefore more likely to change with progression of the illness as well as potentially being more responsive to treatment. One of the main difficulties in conducting biomarker investigations for major psychiatric disorders is the relative inconsistency in clinical diagnoses between disorders such as bipolar and schizophrenia. This has led some researchers to investigate biomarkers associated with core symptoms of these disorders, such as psychosis. The aim of this review is to evaluate the contribution of post-mortem brain investigations to elucidating the pathophysiology pathways involved in schizophrenia and psychosis, with an emphasis on major neurotransmitter systems that have been implicated. This data will then be compared to functional neuroimaging findings as well as findings from blood based gene expression investigations in schizophrenia in order to highlight the relative overlap in pathological processes between these different modalities used to elucidate pathogenesis of schizophrenia. In addition we will cover some recent and exciting findings demonstrating microRNA (miRNA) dysregulation in both the blood and the brain in patients with schizophrenia. These changes are pertinent to the topic due to their known role in post-transcriptional modification of gene expression with the potential to contribute or underlie gene expression changes observed in schizophrenia. Finally, we will discuss how post-mortem studies may aid future biomarker investigations.

Newer antipsychotics and upcoming molecules for schizophrenia

BACKGROUND

The management of schizophrenia has seen significant strides over the last few decades, due to the increasing availability of a number of antipsychotics. Yet, the diminished efficacy in relation to the negative and cognitive symptoms of schizophrenia, and the disturbing adverse reactions associated with the current antipsychotics, reflect the need for better molecules targeting unexplored pathways.

PURPOSE

To review the salient features of the recently approved antipsychotics; namely, iloperidone, asenapine, lurasidone and blonanserin.

METHODS

We discuss the advantages, limitations and place in modern pharmacotherapy of each of these drugs. In addition, we briefly highlight the new targets that are being explored.

RESULTS

Promising strategies include modulation of the glutamatergic and GABAergic pathways, as well as cholinergic systems.

CONCLUSIONS

Although regulatory bodies have approved only a handful of antipsychotics in recent years, the wide spectrum of targets that are being explored could eventually bring out antipsychotics with improved efficacy and acceptability, as well as the potential to revolutionize psychiatric practice.