A comparison of continuous subcutaneous paliperidone infusion and repeated subcutaneous injection of risperidone free-base in rats

Paliperidone alleviates MK-801-induced damage to prefrontal cortical neurons via the PP2A/PTEN pathway

BACKGROUND

The putative mechanisms underlying the efficacy of the US Food and Drug Administration-approved antipsychotic drug paliperidone for the treatment of schizophrenia deserve additional investigation, which is the aim of the present animal study.

METHODS

The behavioral activities of mice were recorded in the open field test and light-dark box test. The effects of paliperidone on MK-801-induced neuronal damage in the prefrontal cortex were tested by flow cytometry, TUNEL staining assays, and ROS staining assays. The neuroprotective effects of paliperidone on neural dendrites and synapses were evaluated using Golgi staining and Sholl analysis. An adenovirus vector containing a Ca²⁺ indicator was used to monitor the calcium ion concentration in the prefrontal cortex. The expression levels of protein phosphatase 2A (PP2A) and phosphatase and tensin homolog (PTEN) were investigated using Western blotting.

RESULTS

The data showed that MK-801 caused stereotyped behavior in mice and induced synaptic damage and dendritic spine impairment compared with the control, whereas paliperidone ameliorated these changes. Moreover, paliperidone reversed MK-801-induced decreases in PP2A and PTEN levels in prefrontal cortical neurons. Furthermore, in primary cultured cortical neurons and HT-22 cells, paliperidone inhibited cell apoptosis caused by MK-801. In particular, pretreatment with the PP2A inhibitor LB-100 significantly restrained the protective effects of paliperidone on MK-801-treated neurons and on locomotor activity and stereotypical behavior of mice.

LIMITATIONS

Whether other proteins are involved in this pathway and how the pathway works have not been revealed.

CONCLUSION

Our data show that paliperidone alleviates neuronal damage induced by MK-801 via the PP2A/PTEN pathway.

A Flexible-Dose Study of Paliperidone ER in Patients With Nonacute Schizophrenia Previously Treated Unsuccessfully With Oral Olanzapine

OBJECTIVE

The goal of this study was to explore the tolerability, safety, and treatment response of switching from oral olanzapine to paliperidone extended release (ER).

METHODS

Adult patients with nonacute schizophrenia who had been treated unsuccessfully with oral olanzapine were switched to flexible doses of paliperidone ER (3 to 12 mg/d). The primary efficacy outcome was a ≥ 20% improvement in Positive and Negative Syndrome Scale (PANSS) total scores from baseline to endpoint for patients who switched medications because of lack of efficacy with olanzapine and noninferiority versus previous olanzapine treatment (mean endpoint change in PANSS total scores vs. baseline of ≤ 5 points) for patients who switched for reasons other than lack of efficacy. Safety and tolerability were assessed by monitoring adverse events, extrapyramidal symptoms, and weight change.

RESULTS

Of 396 patients, 65.2% were men, mean age was 40.0 ± 12.0 years, and 75.5% had paranoid schizophrenia. Among the patients whose main reason for switching was lack of efficacy, an improvement in the PANSS total score of ≥ 20% occurred in 57.4% of patients. Noninferiority was confirmed for each subgroup of patients whose main reason for switching was something other than lack of efficacy. Paliperidone ER was generally well tolerated. Extrapyramidal symptoms as measured by total Extrapyramidal Symptom Rating Scale scores showed statistically significant and clinically relevant improvements at endpoint, the average weight decreased by 0.8 ± 5.2 kg at endpoint, and a clinically relevant weight gain of ≥ 7% occurred in 8.0% of patients.

CONCLUSION

Paliperidone ER flexibly-dosed over 6 months was well tolerated and associated with a meaningful clinical response in patients with nonacute schizophrenia who had previously been unsuccessfully treated with oral olanzapine.

Treatment response, safety, and tolerability of paliperidone extended release treatment in patients recently diagnosed with schizophrenia

OBJECTIVE

This study was designed to explore the efficacy and tolerability of oral paliperidone extended release (ER) in a sample of patients who were switched to flexible doses within the crucial first 5 years after receiving a diagnosis of schizophrenia.

METHODS

Patients were recruited from 23 countries. Adults with nonacute but symptomatic schizophrenia, previously unsuccessfully treated with other oral antipsychotics, were transitioned to paliperidone ER (3-12 mg/day) and prospectively treated for up to 6 months. The primary efficacy outcome for patients switching for the main reason of lack of efficacy with their previous antipsychotic was at least 20% improvement in Positive and Negative Syndrome Scale (PANSS) total scores. For patients switching for other main reasons, such as lack of tolerability, compliance or 'other', the primary outcome was non-inferiority in efficacy compared with the previous oral antipsychotic.

RESULTS

For patients switching for the main reason of lack of efficacy, 63.1% achieved an improvement of at least 20% in PANSS total scores from baseline to endpoint. For each reason for switching other than lack of efficacy, efficacy maintenance after switching to paliperidone ER was confirmed. Statistically significant improvement in patient functioning from baseline to endpoint, as assessed by the Personal and Social Performance scale, was observed (p < 0.0001). Treatment satisfaction with prior antipsychotic treatment at baseline was rated 'good' to 'very good' by 16.8% of patients, and at endpoint by 66.0% of patients treated with paliperidone ER. Paliperidone ER was generally well tolerated, with frequently reported treatment-emergent adverse events being insomnia, anxiety and somnolence.

CONCLUSIONS

Flexibly dosed paliperidone ER was associated with clinically relevant symptomatic and functional improvement in recently diagnosed patients with non-acute schizophrenia previously unsuccessfully treated with other oral antipsychotics.

Flexible dosing with paliperidone ER in the treatment of patients with acutely exacerbated schizophrenia: results from a single-arm, open-label study

OBJECTIVE

To extend findings from fixed-dose, double-blind, placebo-controlled clinical trials in selected patient populations by using flexibly-dosed oral paliperidone extended-release (ER) in a more naturalistic setting.

METHODS

Adults hospitalized with an acute exacerbation of schizophrenia were prospectively treated with open-label flexibly-dosed paliperidone ER 3-12 mg/day for 6 weeks.

RESULTS

Overall, 294 patients were treated. The primary endpoint, defined as ≥30% improvement in Positive and Negative Syndrome Scale total scores from baseline to endpoint, was achieved by 66.3% of patients. The percentage of patients rated as at least 'markedly ill' in Clinical Global Impression of Severity scale decreased from baseline (74.1%) to endpoint (20.0%). Patient functioning, assessed by the Personal and Social Performance scale, improved significantly from 50.0 ± 14.3 at baseline to 63.6 ± 14.9 at endpoint (p < 0.0001). Concomitant benzodiazepines were newly initiated in 191 patients (65.0%), and new concomitant medications other than benzodiazepines were started after baseline for 133 patients (45.2%), most frequently paracetamol, zolpidem, and zopiclone. No unexpected adverse events were identified.

CONCLUSIONS

These data support findings in more selected patient populations treated with fixed-dose paliperidone ER. Flexibly-dosed paliperidone ER administered in a naturalistic hospital setting to a more representative patient population experiencing an acute episode of schizophrenia, was associated with clinically meaningful treatment response. Strength of conclusions is limited by the open-label design and lack of a comparator group. Furthermore, some of the improvements observed may in part be associated with increased attention provided to patients and concomitant use of psychotropic medications, such as benzodiazepines, during this study.

Effects of controlled-release formulations of atypical antipsychotics on functioning and quality of life of schizophrenic individuals

INTRODUCTION

Controlled-release formulations of atypical antipsychotics have recently been introduced into clinical practice. Clinical studies have indicated that these new therapies induce meaningful improvements in the functioning and quality of life of schizophrenic individuals.

AREAS COVERED

The present analysis makes an attempt to address the clinical relevance of these studies and their contribution to the understanding of the mechanisms of action of these new drugs. A Medline search was done using the keywords 'antipsychotic', 'plasma level', 'quality of life' and 'functioning'.

EXPERT OPINION

After reviewing the literature, it seems that symptom control and side effects may play a role in modulating the functioning and quality of life of schizophrenic individuals treated with controlled-release formulations of atypical antipsychotics. The analysis also highlights that these new drugs may possess peculiarities and similarities in regulating patient functioning. However, the low number of clinical analyses that have focused on these aspects of antipsychotic therapy limits the interpretation of the results. Additional comparative clinical trials are needed to evaluate how the pharmacokinetic/pharmacodynamic properties of antipsychotic drugs may modulate the functioning and quality of life of schizophrenic individuals, as well as to establish whether new clinical benefits may come from the use of these drugs in schizophrenia therapy.