Paliperidone LAI and Aripiprazole LAI Plasma Level Monitoring in the Prophylaxis of Bipolar Disorder Type I with Manic Predominance

Combining predominant polarity and affective spectrum concepts in bipolar disorder: towards a novel theoretical and clinical perspective

This is an overview of recent advances on predominant polarity conceptualization in bipolar disorder (BD). Current evidence on its operationalized definitions, possible contextualization within the affective spectrum, along with its epidemiological impact, and treatment implications, are summarized. Predominant polarity identifies three subgroups of patients with BD according to their mood recurrencies: (i) those with depressive or (ii) manic predominance as well as (iii) patients without any preponderance ('nuclear' type). A predominant polarity can be identified in approximately half of patients, with similar rates for depressive and manic predominance. Different factors may influence the predominant polarity, including affective temperaments. More generally, affective disorders should be considered as existing on a spectrum ranging from depressive to manic features, also accounting for disorders with 'ultrapredominant' polarity, i.e., unipolar depression and mania. While mixed findings emerge on its utility in clinical practice, it is likely that the construct of predominant polarity, in place of conventional differentiation between BD-I and BD-II, may be useful to clarify the natural history of the disorder and select the most appropriate interventions. The conceptualization of predominant polarity seems to reconcile previous theoretical views of both BD and affective spectrum into a novel perspective. It may provide useful information to clinicians for the early identification of possible trajectories of BD and thus guide them when selecting interventions for maintenance treatment. However, further research is needed to clarify the specific role of predominant polarity as a key determinant of BD course, outcome, and treatment response.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotics as a Predictor of Relapse in Schizophrenia Spectrum Disorders: A 1-Year Pilot Study

BACKGROUND

Long-acting injectable antipsychotics (LAIs) have been shown to reduce acute episodes of schizophrenia spectrum disorders (SSDs). However, breakthrough relapses are frequent, possibly because of underdosing in clinical practice. In this framework, the advantages of therapeutic drug monitoring (TDM) may be overlooked. This study explored the association of low steady-state LAI levels with a higher risk of relapse in SSDs, despite the use of a licensed posology.

METHODS

Forty-eight clinically stable outpatients with SSD underwent LAI-TDM using liquid chromatography-mass spectrometry for routine observational purposes. Baseline anamnestic, pharmacological, and psychometric evaluations compared subjects with "under-range" versus "in-range" LAI serum levels; between-group comparisons for different LAI treatments were also performed. A binary logistic regression explored which baseline factors (age, sex, previous hospitalizations, psychopathology, specific LAI treatment, and underrange serum levels) predicted relapse during the next 12 months.

RESULTS

Baseline comparisons did not show significant between-group differences, except for a higher percentage of underrange values in individuals receiving olanzapine pamoate. A total of 10 patients (20.8%) relapsed during the follow-up; only underrange LAI levels predicted the event (odds ratio 0.03, 95% confidence interval 0.01-0.36; P = 0.005).

CONCLUSIONS

Even if relapse remains as a multifactorial event, LAI-TDM may identify subjects at risk for this negative outcome, thus optimizing antipsychotic maintenance treatment in the context of precision medicine. The finding of underrange LAI plasma levels in real-world practice should prompt adequate monitoring of clinically stable outpatients to identify the early signs of psychopathological deterioration.

Current Status of Therapeutic Drug Monitoring in Mental Health Treatment: A Review

Therapeutic drug monitoring (TDM) receives growing interest in different psychiatric clinical settings (emergency, inpatient, and outpatient services). Despite its usefulness, TDM remains underemployed in mental health. This is partly due to the need for evidence about the relationship between drug serum concentration and efficacy and tolerability, both in the general population and even more in subpopulations with atypical pharmacokinetics. This work aims at reviewing the scientific literature published after 2017, when the most recent guidelines about the use of TDM in mental health were written. We found 164 pertinent records that we included in the review. Some promising studies highlighted the possibility of correlating early drug serum concentration and clinical efficacy and safety, especially for antipsychotics, potentially enabling clinicians to make decisions on early laboratory findings and not proceeding by trial and error. About populations with pharmacokinetic peculiarities, the latest studies confirmed very common alterations in drug blood levels in pregnant women, generally with a progressive decrease over pregnancy and a very relevant dose-adjusted concentration increase in the elderly. For adolescents also, several drugs result in having different dose-related concentration values compared to adults. These findings stress the recommendation to use TDM in these populations to ensure a safe and effective treatment. Moreover, the integration of TDM with pharmacogenetic analyses may allow clinicians to adopt precise treatments, addressing therapy on an individual pharmacometabolic basis. Mini-invasive TDM procedures that may be easily performed at home or in a point-of-care are very promising and may represent a turning point toward an extensive real-world TDM application. Although the highlighted recent evidence, research efforts have to be carried on: further studies, especially prospective and fixed-dose, are needed to replicate present findings and provide clearer knowledge on relationships between dose, serum concentration, and efficacy/safety.

Therapeutic Reference Range for Aripiprazole in Schizophrenia Revised: a Systematic Review and Metaanalysis

RATIONALE

While one of the basic axioms of pharmacology postulates that there is a relationship between the concentration and effects of a drug, the value of measuring blood levels is questioned by many clinicians. This is due to the often-missing validation of therapeutic reference ranges.

OBJECTIVES

Here, we present a prototypical meta-analysis of the relationships between blood levels of aripiprazole, its target engagement in the human brain, and clinical effects and side effects in patients with schizophrenia and related disorders.

METHODS

The relevant literature was systematically searched and reviewed for aripiprazole oral and injectable formulations. Population-based concentration ranges were computed (N = 3,373) and pharmacokinetic influences investigated.

RESULTS

Fifty-three study cohorts met the eligibility criteria. Twenty-nine studies report blood level after oral, 15 after injectable formulations, and nine were positron emission tomography studies. Conflicting evidence for a relationship between concentration, efficacy, and side effects exists (assigned level of evidence low, C; and absent, D). Population-based reference ranges are well in-line with findings from neuroimaging data and individual efficacy studies. We suggest a therapeutic reference range of 120-270 ng/ml and 180-380 ng/ml, respectively, for aripiprazole and its active moiety for the treatment of schizophrenia and related disorders.

CONCLUSIONS

High interindividual variability and the influence of CYP2D6 genotypes gives a special indication for Therapeutic Drug Monitoring of oral and long-acting aripiprazole. A starting dose of 10 mg will in most patients result in effective concentrations in blood and brain. 5 mg will be sufficient for known poor metabolizers.

The Switch From Paliperidone Long-Acting Injectable 1- to 3-Monthly: Clinical Pharmacokinetic Evaluation in Patients With Schizophrenia (Preliminary Data)

PURPOSE/BACKGROUND

The aim of the study was a preliminary evaluation of the maintenance of clinical efficacy and tolerability of paliperidone palmitate in patients with schizophrenia during the transition phase from 1-monthly paliperidone palmitate formulation (PP1M) to PP3M, with the evaluation of plasma levels of the drug.

METHODS/PROCEDURES

A prospective observational study was conducted for 13 months involving 22 outpatients, aged 18 to 66 years and clinically stabilized. Patients were affected by schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria. For each patient, clinical assessment, safety and tolerability, and drug plasma level determination were performed. Clinical efficacy was assessed by Brief Psychiatric Rating Scale, Positive and Negative Symptom Scale, and Hamilton Rating Scale for Depression. During the first 4 months of the study, once-monthly paliperidone palmitate was administered, and then during the following 9 months, the 3-monthly formulation was administered.

FINDINGS/RESULTS

The time course of the Brief Psychiatric Rating Scale total scores showed a statistically significant (P = 0.006) improvement from T0 to T8; Positive and Negative Symptom Scale scores showed a similar time course, with a statistically significant (P = 0.0016) reduction of the mean total score; Hamilton Rating Scale for Depression mean scores showed a statistically significant (P = 0.003) reduction with substantial maintenance of clinical stabilization of the patients. Only 1 patient dropped out after the first PP3M injection.

IMPLICATIONS/CONCLUSIONS

Our preliminary data currently confirm the maintenance of clinical stability shifting from PP1M to PP3M.

Clinical response in patients treated with once-monthly paliperidone palmitate: analysis of a therapeutic drug monitoring (TDM) database

To investigate pharmacokinetic correlates of clinical response in patients treated with once-monthly paliperidone palmitate (PP1M) injections at steady state. Plasma concentrations and dose-adjusted-plasma concentrations (C/D) of paliperidone from a naturalistic therapeutic drug monitoring (TDM) database were compared between responders and non-responders using the Clinical Global Impressions-Improvement scale (CGI-I) ratings. Analyses were based on the non-parametric Mann-Whitney U test and the Pearson Chi-squared test (χ²) with a significance level of 0.05. Subgroup analyses were performed separately in patients with schizophrenia spectrum, schizoaffective disorders and bipolar disorders. Comparing 93 responders with 80 non-responders, we detected no significant differences in the proportion of females, age, and body mass index (p's ranging 0.18-0.83); there were more smokers in the group of non-responders (p = 0.04), which also included more patients with bipolar disorders (p = 0.014). Despite the lack of differences for prescribed PP1M doses and dose intervals (p = 0.42 and p = 0.11, respectively), non-responders had higher paliperidone plasma concentrations and C/D levels (p = 0.033 and p = 0.021, respectively). Subgroup analyses did not yield differences for paliperidone plasma and C/D levels between non-responders and responders with schizophrenia spectrum (p = 0.099 and p = 0.14, respectively) and bipolar disorders (p = 0.95 and p = 0.75, respectively); dose-adjusted plasma concentrations were higher in non-responders compared to responders with schizoaffective disorders (p = 0.039), while no differences were reported for plasma levels (p = 0. 15). Our results show that paliperidone plasma concentrations over injection doses may be associated with patterns of clinical response suggesting potential utility of TDM as part of PP1M-based maintenance treatment.

The Relation between the Plasma Concentrations of Long-Acting Atypical Antipsychotics and Clinical Effectiveness in Patients Affected by Schizophrenia or Schizoaffective Disorder: A Comprehensive Overview

Atypical antipsychotic depot medications are currently recommended for patients with schizophrenia (SCZ) to prevent relapse and ameliorate the long-term prognosis of these patients. This review critically summarizes the available data about the association between the plasma concentrations of long-acting Second- Generation Antipsychotics (SGAs) and the clinical effectiveness of these compounds in patients affected by SCZ or schizoaffective disorder. Our question is if the measurement of these concentrations can be helpful for clinicians in predicting treatment response and clinical stabilization of patients. Bibliographic research on the main databases was performed, and 13 studies were finally included in this review. Contrasting results were found between plasma concentrations of long-acting injectable (LAI) risperidone and clinical amelioration according to rating scale scores. Data are too scanty to draw conclusions for olanzapine and paliperidone. In contrast, despite small sample sizes, data are quite concordant in showing a relation between long-acting SGA plasma concentrations and D2 receptor occupancy. Despite the preliminary encouraging results, particularly for D2 receptor occupancy, future research with larger samples will have to confirm the clinical usefulness of measuring LAI SGA plasma concentrations to predict the clinical response of patients affected by severe mental conditions such as SCZ.

Pharmacokinetic Correlates of Once-Monthly Paliperidone Palmitate-Related Adverse Drug Reactions

OBJECTIVE

The objective of this study was to investigate associations between pharmacokinetic correlates and once-monthly paliperidone palmitate (PP1M)-related adverse drug reactions (ADRs).

METHODS

Plasma concentrations and dose-adjusted plasma concentrations ('concentration-by-dose' [C/D]) of paliperidone from a naturalistic therapeutic drug monitoring database of PP1M-treated patients were compared between patients with ADRs, classified according to the Udvalg for Kliniske Undersogelser side-effect rating scales categories, and patients without ADRs. Analyses included non-parametric tests and a logistic regression model with a significance level set at 0.05.

RESULTS

In 172 patients, we found no differences in sex, age, smoking, body mass index, PP1M dose, paliperidone plasma concentrations, and C/D values (p > 0.05) between 44 patients with and 128 patients without PP1M-related ADRs. We did not detect differences when specifying for different types of ADRs (p > 0.05). Injection intervals were shorter in patients with vs patients without ADRs (p = 0.03). The logistic regression did not report effects for sex, plasma concentrations, or C/D values (p > 0.05). Post hoc analyses in male patients receiving PP1M every 28 weeks reported higher paliperidone concentrations and C/D values in patients with vs without ADRs (p = 0.049 and p = 0.022). Within the group of male patients, we found an odds ratio of 3.07 for PP1M-associated ADRs in patients with C/D values above 7.7 (ng/mL)/(mg/day).

CONCLUSIONS

Our findings did not reveal distinct patterns of paliperidone concentrations in patients with PP1M-related ADRs. However, male patients receiving PP1M every 28 days with C/D values higher than 7.7 (ng/mL)/(mg/day) showed a higher risk for ADRs, implying that therapeutic drug monitoring may be useful in assessing the risk of PP1M-related ADRs.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotic Drugs

BACKGROUND

The use of therapeutic drug monitoring (TDM) to guide treatment with long-acting injectable (LAI) antipsychotics, which are increasingly prescribed, remains a matter of debate. The aim of this review was to provide a practical framework for the integration of TDM when switching from an oral formulation to the LAI counterpart, and in maintenance treatment.

METHODS

The authors critically reviewed 3 types of data: (1) positron emission tomography data evaluating dopamine (D2/D3) receptor occupancy related to antipsychotic concentrations in serum or plasma; D2/D3 receptors are embraced as target sites in the brain for antipsychotic efficacy and tolerability, (2) pharmacokinetic studies evaluating the switch from oral to LAI antipsychotics, and (3) pharmacokinetic data for LAI formulations. Based on these data, indications for TDM and therapeutic reference ranges were considered for LAI antipsychotics.

RESULTS

Antipsychotic concentrations in blood exhibited interindividual variability not only under oral but also under LAI formulations because these concentrations are affected by demographic characteristics such as age and sex, genetic peculiarities, and clinical variables, including comedications and comorbidities. Reported data combined with positron emission tomography evidence indicated a trend toward lower concentrations under LAI administration than under oral medications. However, the available evidence is insufficient to recommend LAI-specific therapeutic reference ranges.

CONCLUSIONS

Although TDM evidence for newer LAI formulations is limited, this review suggests the use of TDM when switching an antipsychotic from oral to its LAI formulation. The application of TDM practice is more accurate for dose selection than the use of dose equivalents as it accounts more precisely for individual characteristics.