Long-acting injectable antipsychotics: focus on olanzapine pamoate

Role of Modeling and Simulation in Preclinical and Clinical Long-Acting Injectable Drug Development

Innovations in the field of long-acting injectable drug development are increasingly being reported. More advanced in vitro and in vivo characterization can improve our understanding of the injection space and aid in describing the long-acting injectable (LAI) drug's behavior at the injection site more mechanistically. These innovations may enable unlocking the potential of employing a model-based framework in the LAI preclinical and clinical space. This review provides a brief overview of the LAI development process before delving deeper into the current status of modeling and simulation approaches in characterizing the preclinical and clinical LAI pharmacokinetics, focused on aqueous crystalline suspensions. A closer look is provided on in vitro release methods, available biopharmaceutical models and reported in vitro/in vivo correlations (IVIVCs) that may advance LAI drug development. The overview allows identifying the opportunities for use of model-informed drug development approaches and potential gaps where further research may be most warranted. Continued investment in improving our understanding of LAI PK across species through translational approaches may facilitate the future development of LAI drug products.

Seventy Years of Antipsychotic Development: A Critical Review

Since the mid-1950s discovery of the first effective antipsychotic medications (APM), we have only been able to improve the tolerability but not the overall efficacy of currently available APMs, as reflected by effectiveness trials in Europe and the United States. This inability to develop more effective APMs is attributable to multiple factors, including failure to create and use assessment tools to assess core symptom domains in schizophrenia, move beyond the dopaminergic hypothesis and to develop "me too" drugs, imposing ill-defined research domain criteria, and lacking federal funding for clinical trials. The classification of APMs is also confusing, including second-generation, partial agonists, and multimodal APMs in the same class of APMs, despite significant differences in their mechanisms of action. Other factors stagnating drug development include inadequate sample sizes to address heterogeneity, lack of statistical measures correlating with clinical significance, using the atheoretical basis of psychiatric diagnoses, failure to control placebo response, and high cost of newer and perhaps more tolerable APMs. Furthermore, there has been a failure to develop early predictors of antipsychotic response and various tools to optimize an APM response. Finally, some mental health providers are also responsible for the suboptimal use of APMs, by using excessive maintenance doses, often with irrational polypharmacy, further compromising effectiveness and medication adherence. However, some bright spots in antipsychotic development include improved tolerability of APMs and long-acting injectables to address the high prevalence of medication nonadherence. This review critically reviews 70 years of antipsychotic development, the reasons behind the failure to develop more effective APMs, and suggestions for future direction.

3D-printed implantable devices with biodegradable rate-controlling membrane for sustained delivery of hydrophobic drugs

Implantable drug delivery systems offer an alternative for the treatments of long-term conditions (i.e. schizophrenia, HIV, or Parkinson’s disease among many others). The objective of the present work was to formulate implantable devices loaded with the model hydrophobic drug olanzapine (OLZ) using robocasting 3D-printing combined with a pre-formed rate controlling membrane. OLZ was selected as a model molecule due to its hydrophobic nature and because is a good example of a molecule used to treat a chronic condition schizophrenia. The resulting implants consisted of a poly(ethylene oxide) (PEO) implant coated with a poly(caprolactone) (PCL)-based membrane. The implants were loaded with 50 and 80% (w/w) of OLZ. They were prepared using an extrusion-based 3D-printer from aqueous pastes containing 36–38% (w/w) of water. The printing process was carried out at room temperature. The resulting implants were characterized by using infrared spectroscopy, scanning electron microscopy, thermal analysis, and X-ray diffraction. Crystals of OLZ were present in the implant after the printing process. In vitro release studies showed that implants containing 50% and 80% (w/w) of OLZ were capable of providing drug release for up to 190 days. On the other hand, implants containing 80% (w/w) of OLZ presented a slower release kinetics. After 190 days, total drug release was ca. 77% and ca. 64% for implants containing 50% and 80% (w/w) of OLZ, respectively. The higher PEO content within implants containing 50% (w/w) of OLZ allows a faster release as this polymer acts as a co-solvent of the drug.

Drug Nanocrystals: Focus on Brain Delivery from Therapeutic to Diagnostic Applications

The development of new drugs is often hindered by low solubility in water, a problem common to nearly 90% of natural and/or synthetic molecules in the discovery pipeline. Nanocrystalline drug technology involves the reduction in the bulk particle size down to the nanosize range, thus modifying its physico-chemical properties with beneficial effects on drug bioavailability. Nanocrystals (NCs) are carrier-free drug particles surrounded by a stabilizer and suspended in an aqueous medium. Due to high drug loading, NCs maintain a potent therapeutic concentration to produce desirable pharmacological action, particularly useful in the treatment of central nervous system (CNS) diseases. In addition to the therapeutic purpose, NC technology can be applied for diagnostic scope. This review aims to provide an overview of NC application by different administration routes, especially focusing on brain targeting, and with a particular attention to therapeutic and diagnostic fields. NC therapeutic applications are analyzed for the most common CNS pathologies (i.e., Parkinson's disease, psychosis, Alzheimer's disease, etc.). Recently, a growing interest has emerged from the use of colloidal fluorescent NCs for brain diagnostics. Therefore, the use of NCs in the imaging of brain vessels and tumor cells is also discussed. Finally, the clinical effectiveness of NCs is leading to an increasing number of FDA-approved products, among which the NCs approved for neurological disorders have increased.

Consideration of Long-Acting Injectable Antipsychotics for Polypharmacy Regimen in the Treatment of Schizophrenia: Put It on the Table or Not?

Antipsychotic monotherapy (APM) is considered best-acceptable treatment option regardless of antipsychotic class and formulation types for treating schizophrenia. However, antipsychotic polypharmacy (APP) has been also widely utilized in routine clinical practice. Despite APP has some clinical benefits it has also numerous pitfalls in relation with increased total number and doses of APs leading to adverse events as well as decrease of treatment adherence and persistence resulting in poor clinical outcomes. Recent introduction of long-acting injectable antipsychotics (LAIs) to the market has offered a chance for better medication adherence/persistence and also provided a simplification of treatment regime leading to more stabilized treatment for schizophrenia patients. When we cannot stay away from APP in the treatment of schizophrenia, clinicians need to find more proper APP regimens and thereby utilization of APP in efficient way should be a practical strategy to benefit schizophrenia patient in a real world treatment setting. With this regard, LAIs can be one of available APP regimen for treatment of schizophrenia in routine practice since their clinical utility and pharmacokinetic stability over oral APs have been well-elaborated today. However, when we have to commence LAIs as a part of APP with oral APs or other LAIs, every effort should be made before doing so whether or not validated and available treatment options or other clinical factors were not done or evaluated yet. Any treatment guidelines do not support APP regardless of the formulation of APP regimen or address two or more LAIs for treatment of schizophrenia till today.

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.

Clinical correlates of paliperidone palmitate and aripiprazole monohydrate prescription for subjects with schizophrenia-spectrum disorders: findings from the STAR Network Depot Study

This study, based on the 'Servizi Territoriali Associati per la Ricerca' (STAR) Network Depot Study nationwide baseline data, explored whether individual symptoms severity and clusters might influence the prescription of paliperidone palmitate 1-month (PP1M) vs. aripiprazole monohydrate. The Brief Psychiatric Rating Scale (BPRS) was used to assess psychopathology and relevant symptoms clusters. Drug Attitude Inventory, 10 items, was used to test attitude towards medications. Adherence to treatments was rated according to the Kemp seven-point scale. We assessed for eligibility 451 individuals and, among them, we included 195 subjects (n = 117 who started PPM1 and n = 78 aripiprazole monohydrate). Individuals were comparable in terms of age, gender, treatment years, recent hospitalizations, previous long-acting injectable antipsychotic treatments, additional oral treatments, attitude toward drugs, medication adherence, and alcohol/substance-related comorbidities. Subjects starting PP1M presented higher BPRS overall (P = 0.009), positive (P = 0.015), and negative (P = 0.010) symptom scores compared to subjects starting aripiprazole monohydrate. Results were confirmed by appropriate regression models and propensity score matching analysis. No differences were found comparing the other BPRS subscale scores: affect, resistance, and activation. Clinicians may be more prone to prescribe PPM1, rather than aripiprazole monohydrate, to subjects showing higher overall symptom severity, including positive and negative symptoms. No additional clinical factors influenced prescribing attitudes in our sample.

Long-Acting Injectable Statins-Is It Time for a Paradigm Shift?

In recent years, advances in pharmaceutical processing technologies have resulted in development of medicines that provide therapeutic pharmacokinetic exposure for a period ranging from weeks to months following a single parenteral administration. Benefits for adherence, dose and patient satisfaction have been witnessed across a range of indications from contraception to schizophrenia, with a range of long-acting medicines also in development for infectious diseases such as HIV. Existing drugs that have successfully been formulated as long-acting injectable formulations have long pharmacokinetic half-lives, low target plasma exposures, and low aqueous solubility. Of the statins that are clinically used currently, atorvastatin, rosuvastatin, and pitavastatin may have compatibility with this approach. The case for development of long-acting injectable statins is set out within this manuscript for this important class of life-saving drugs. An overview of some of the potential development and implementation challenges is also presented.

THE METABOLIC SYNDROME IN OUTPATIENTS WITH PSYCHOSIS: A COMPARATIVE STUDY BETWEEN LONG ACTING INJECTABLE OLANZAPINE AND RISPERIDONE

CONTEXT

Literature shows that patients taking antipsychotic medication risk developing metabolic complications.

OBJECTIVE

The study aims to compare the presence of the metabolic syndrome (MS) and its components in outpatients treated with long acting injectable (LAI) olanzapine and risperidone.

DESIGN

A double-center study was performed on outpatients with psychosis, which were divided into two samples: one treated with olanzapine and another with risperidone.

SUBJECTS AND METHODS

The following data were analyzed: age, gender, severity of psychiatric symptoms, blood pressure, waist circumference, fasting blood glucose, lipid profile, tobacco use, medication, and time intervals related to psychosis duration (pre-LAI and LAI treatment).

RESULTS

The study included 77 patients with schizophrenia and schizoaffective disorder. MS was present in 45 (58.4%) patients. Subjects with MS and abdominal obesity had higher durations of psychosis and of LAI treatment. Patients with hypertension had a higher pre-LAI treatment interval. Risperidone was associated with higher rates of hypertension and higher values of abdominal circumference than olanzapine.

CONCLUSIONS

The presence of MS is related to the duration of the psychosis and the time spent on LAI treatment with no differences between olanzapine and risperidone. Hypertension may be a consequence of age, disorder induced stress, or of treatment with risperidone.

Development and evaluation of intramuscularly administered nano/microcrystal suspension

INTRODUCTION

Formulation of nanocrystals is one of the most important drug delivery systems for poorly soluble drug molecules. Nanocrystals are produced by techniques like precipitation, media milling, high-pressure homogenization, and so on. In order to achieve sustained release and higher absorption of nanosuspensions, intramuscularly administered nanosuspensions have been developed. As well, intramuscularly administered nanosuspensions have been implemented in order to improve the bioavailability of drug nanocrystals which have both a low oral bioavailability and cannot be administered by intravenous injection routes.

AREAS COVERED

This review summarizes studies that have focused on the production, classification, in vitro release and in vivo pharmacokinetics of intramuscularly administered nanosuspensions. In order to avoid common drawbacks of intramuscularly administered nanosuspensions, such as tissue residues and some local tissue damage, nanosuspensions with a reduced administration volume of high drug loading and extended therapeutic effects are developed.

EXPERT OPINION

Intramuscularly administered nano/micro crystal suspensions have been developed for the treatment of various diseases such as schizophrenia, hormone disordered diseases, HIV and more. Additionally, intramuscularly administered nanosuspensions are also a good route for the development of traditional chinese medicines which have lower oral bioavailability and are not suitable for intravenous injection.

A New Level A Type IVIVC for the Rational Design of Clinical Trials Toward Regulatory Approval of Generic Polymeric Long-Acting Injectables

Chronic neuropsychiatric disorders and diabetes mellitus affect millions of patients and require long-term supervision and expensive medical care. Although repeated drug administration can help manage these diseases, relapses and re-hospitalization owing to patient non-adherence and reduced therapeutic efficacy remain challenging. In response, long-acting injectables, which provide sustained drug release over longer periods at concentrations close to therapeutic ranges, have been proposed. Recent advancements include polymeric long-acting injectables (pLAIs), in which the active pharmaceutical ingredient (API) is encapsulated within U.S. Food and Drug Administration (FDA)-approved biocompatible polymers, such as poly(lactic-co-glycolic acid), or PLGA. Despite significant progress and development in the global pLAI market, FDA guidance for the approval of complex drug products, such as generic pLAIs, is not clearly defined. Although in vitro to in vivo correlation (IVIVC) can facilitate the identification of critical quality attributes (CQAs), drug formulations, and in vitro test platforms for evaluating drug performance in vivo, the application of IVIVC in order to shortlist time- and resource-intensive clinical trials for generic pLAIs has not been reported. Here, we propose a new Level A Type IVIVC that directly correlates the in vitro outcomes, such as drug dissolution, of candidate generic formulations with the clinical characteristics, such as drug absorption, of a reference listed drug (RLD), to help identify the specific generic pLAI formulations with clinical absorptions that are likely to be similar to that of the RLD, thereby reducing the number of clinical trials required for evaluation of clinical bioequivalence (BE). Therefore, the scope of the proposed method is intended only for the rational design of clinical trials, i.e., to shortlist the specific pLAI generic formulations for clinical BE evaluation, and not necessarily to analyze drug performances (i.e., drug safety and effectiveness) in the shortlisted clinical trials or post-approval. Once validated, this method will be of great value to developers of generic pLAIs and regulatory bodies to accelerate their approval of these generic pLAIs.

Gray matter volumes may predict the clinical response to paliperidone palmitate long-acting in acute psychosis: A pilot longitudinal neuroimaging study

In schizophrenia, paliperidone palmitate (PP) long acting injectable (LAI) has been reported to sustain plasma concentrations and improve clinical symptoms. Moreover, it has also been demonstrated the important role of total gray matter (GM) volumes in predicting the clinical outcome. However, no studies investigating the association between PP-LAI treatment and brain morphometry has been published so far. Therefore, the main aim of our 24 weeks prospective observational exploratory study was to investigate the relation between brain anatomy and clinical outcome in seven patients with acute psychosis treated with PP-LAI. At baseline and every month (from T0 to T6) patients were clinically evaluated with the Brief Psychiatric Rating Scale (BPRS). 3T Magnetic Resonance Imaging at baseline was acquired and total GM and intracranial volumes were extracted to explore their predictive values on BPRS scores. After 24 weeks of treatment with PP-LAI, patients showed statistically significant improvements in BPRS scores. Moreover, subjects with higher total GM volumes had a significantly higher BPRS improvement at 24 weeks compared to patients with lower total GM volumes. Our findings confirm the effectiveness of PP-LAI in treating acute psychosis and suggest that greater GM volumes predict drug response, potentially supporting a favorable prognosis.

Strengths, weaknesses, opportunities and challenges for long acting injectable therapies: Insights for applications in HIV therapy

Advances in solid drug nanoparticle technologies have resulted in a number of long-acting (LA) formulations with the potential for once monthly or longer administration. Such formulations offer great utility for chronic diseases, particularly when a lack of medication compliance may be detrimental to treatment response. Two such formulations are in clinical development for HIV but the concept of LA delivery has its origins in indications such as schizophrenia and contraception. Many terms have been utilised to describe the LA approach and standardisation would be beneficial. Ultimately, definitions will depend upon specific indications and routes of delivery, but for HIV we propose benchmarks that reflect perceived clinical benefits and available data on patient attitudes. Specifically, we propose dosing intervals of ≥1week, ≥1month or ≥6months, for oral, injectable or implantable strategies, respectively. This review focuses upon the critical importance of potency in achieving the LA outcome for injectable formulations and explores established and emerging technologies that have been employed across indications. Key technological challenges such as the need for consistency and ease of administration for drug combinations, are also discussed. Finally, the review explores the gaps in knowledge regarding the pharmacology of drug release from particulate-based LA injectable suspensions. A number of hypotheses are discussed based upon available data relating to local drug metabolism, active transport systems, the lymphatics, macrophages and patient-specific factors. Greater knowledge of the mechanisms that underpin drug release and protracted exposure will help facilitate further development of this strategy to achieve the promising clinical benefits.

Olanzapine pamoate for the treatment of schizophrenia--a safety evaluation

INTRODUCTION

Non-adherence to long-term treatment is a major issue for patients with schizophrenia and is associated with an increased risk of relapse. Long-acting injectable (LAI) antipsychotics can offer a useful option to improve adherence. Due to the type of sustained-release mechanism, olanzapine pamoate (OLAI) can differ in safety as compared with oral olanzapine. Recent safety data concerning olanzapine pamoate required an update of previous systematic reviews.

AREAS COVERED

Safety data were found in US and EU clinical trial registries, and a literature search was undertaken using the databases PubMed and EMBASE to find all relevant published studies. Where appropriate, the number needed to harm and 95% confidence interval for categorical safety outcomes were calculated.

EXPERT OPINION

The safety profile of OLAI was similar to the well-known safety profile of oral olanzapine, except for the risk of occurrence of post-injection delirium/sedation syndrome (PDSS). Olanzapine pamoate can be a choice for schizophrenic patients with a history of response to and acceptable tolerance of oral olanzapine, who have easy access to mental healthcare settings with emergency services for the treatment of PDSS. Long-term, prospective studies assessing the efficacy and safety of OLAI and head-to-head comparisons with other LAI and oral antipsychotics are needed.

Modeling the Time Course of the Tissue Responses to Intramuscular Long-acting Paliperidone Palmitate Nano-/Microcrystals and Polystyrene Microspheres in the Rat

Long-acting injectable (LAI) drug suspensions consist of drug nano-/microcrystals suspended in an aqueous vehicle and enable prolonged therapeutic drug exposure up to several months. The examination of injection site reactions (ISRs) to the intramuscular (IM) injection of LAI suspensions is relevant not only from a safety perspective but also for the understanding of the pharmacokinetics. The aim of this study was to perform a multilevel temporal characterization of the local and lymphatic histopathological/immunological alterations triggered by the IM injection of an LAI paliperidone palmitate suspension and an analog polystyrene suspension in rats and identify critical time points and parameters with regard to the host response. The ISRs showed a moderate to marked chronic granulomatous inflammation, which was mediated by multiple cyto-/chemokines, including interleukin-1β, monocyte Chemoattractant Protein-1, and vascular endothelial growth factor. Lymphatic uptake and lymph node retention of nano-/microparticles were observed, but the contribution to the drug absorption was negligible. A simple image analysis procedure and empirical model were proposed for the accurate evaluation of the depot geometry, cell infiltration, and vascularization. This study was designed as a reference for the evaluation and comparison of future LAIs and to support the mechanistic modeling of the formulation–physiology interplay regulating the drug absorption from LAIs.

"Long-acting" olanzapine in maintenance therapy of schizophrenia: A study with plasma levels

INTRODUCTION

This prospective study was performed to evaluate clinical efficacy and tolerability of olanzapine long-acting injection (OLZ-LAI) and the relation between OLZ plasma level (PL) and the clinical outcome in maintenance therapy of schizophrenia.

MATERIAL AND METHODS

Twenty-five chronic schizophrenic outpatients with age ranging from 18 to 65 years were included in this 9-month study. Patients were given a dosage of either 210 or 300 or 405 mg of OLZ-LAI every 28 days. Patients were evaluated at baseline and every four weeks by Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Symptom Scale (PANSS); at the same time, PL of OLZ was determined. The metabolic profile (aspartate aminotransferase, alanine aminotransferase, high-density lipoprotein, low-density lipoprotein, total cholesterol, and glucose levels) was analyzed every two months.

RESULTS

BPRS and total PANSS showed a statistically significant improvement from T2 with a clinical stabilization of psychopathological picture. PL ranged from 4.0 to 78.9 ng/ml (mean 20.59 ng/ml ± 14.66 standard deviation). The coefficient of variation of PLs was related to clinical stabilization. No post-injection delirium sedation syndrome occurred.

CONCLUSIONS

Our data reveal the efficacy of OLZ-LAI in maintenance treatment of schizophrenia at lower dosages also in comparison with that of oral therapy. OLZ-LAI seems to be useful for guaranteeing constant PL of the drug. A lesser variation of PL was the most predictable factor associated with maintenance of clinical benefit.

Post-injection delirium/sedation syndrome in patients treated with olanzapine pamoate: mechanism, incidence, and management

Second-generation antipsychotics (SGAs) are a mainstay in the treatment of patients with schizophrenia. However, continuity in intake of the prescribed medication has been one of the greatest challenges in these patients. One option to improve medication adherence is to prescribe depot or long-acting injectable formulations (LAIs) of antipsychotics. Following risperidone, several other SGAs have been introduced as LAIs. Olanzapine pamoate, paliperidone palmitate, and aripiprazole are the new-generation LAIs, which are available for 2- to 4-week intervals of application in many countries. The literature shows a clear advantage of these drugs over placebo regarding symptom reduction and relapse prevention. LAIs show a similar safety profile to oral formulations of the relevant drug, with the exception of olanzapine pamoate, which can lead to rare cases of post-injection delirium/sedation syndrome (PDSS). PDSS is characterized by heavy sedation (possibly including coma) and/or delirium after injection. During PDSS events, patients show higher plasma concentrations of olanzapine, leading to the assumption that unintended partial intravascular injection or blood vessel injury during the injection is causative of PDSS. Therefore, a risk-management plan proposing an observation period of 3 h was introduced. In August 2013, a new proposal by the European Medicines Agency terminated the requirement to accompany these patients to their next destination, although this requirement remains in place according to US FDA recommendations.

Long-acting olanzapine versus long-acting risperidone for schizophrenia in Spain - a cost-effectiveness comparison

BACKGROUND

In schizophrenia, medication adherence is critical to achieve better patient outcomes and to avoid relapses, which are responsible for a significant proportion of total healthcare costs for this chronic illness. The aim of this study was to assess the cost-effectiveness of olanzapine long-acting injection (OLAI) compared with risperidone long-acting injection (RLAI) in patients with schizophrenia in Spain.

METHODS

A discrete event simulation (DES) model was developed from a Spanish healthcare system perspective to estimate clinical and economic outcomes for patients with schizophrenia over a five-year period. Patients who had earlier responded to oral medication and have a history of relapse due to adherence problems were considered. Identical model populations were treated with either OLAI or RLAI. In the absence of a head-to-head clinical trial, discontinuation and relapse rates were obtained from open-label studies. The model accounted for age, gender, risks of relapse and discontinuation, relapse management, hospitalization, treatment switching and adverse events. Direct medical costs for the year 2011 and outcomes including relapse avoided, life years (LYs), and quality-adjusted life years (QALYs) were discounted at a rate of 3%.

RESULTS

When comparing RLAI and OLAI, the model predicts that OLAI would decrease 5-year costs by €2,940 (Standard Deviation between replications 300.83), and result in a QALY and LY gains of 0.07 (SD 0.019) and 0.04 (SD 0.025), respectively. Patients on OLAI had fewer relapses compared to RLAI (1.392 [SD 0.035] vs. 1.815 [SD 0.035]) and fewer discontinuations (1.222 [SD 0.031] vs. 1.710 [SD 0.039]). Sensitivity analysis indicated that the study was robust and conclusions were largely unaffected by changes in a wide range of parameters.

CONCLUSIONS

The present evaluation results in OLAI being dominant over RLAI, meaning that OLAI represents a more effective and less costly alternative compared to RLAI in the treatment of patients with schizophrenia in the Spanish setting.

Pharmacokinetics of olanzapine long-acting injection: the clinical perspective

Olanzapine long-acting injection (OLAI) is a sustained-release depot antipsychotic for the treatment of schizophrenia in adults. Our objective was to explain the pharmacokinetics of OLAI to provide clinical insight. Simulation models and data from clinical trials are presented. Olanzapine concentrations were observed immediately upon injection. Half-life was ∼30 days, controlled by the slow rate of intramuscular absorption rather than the 30-h elimination rate-based half-life of oral olanzapine. As each injection builds on the drug still being released from previous injections, concentrations increase gradually until a steady state is reached after ∼3 months. Concentrations were similar to oral olanzapine and proportional to the dose; the average steady-state concentrations (10th-90th percentile) for the 150, 210, and 300 mg/2-week doses were 16-32, 15-55, and 20-67 ng/ml, respectively, and those for the 300 and 405 mg/4-week doses were 19-48 and 19-62 ng/ml, respectively. Peak concentrations most often occurred at 2-4 days after injection. Peak-to-trough fluctuation was greater for the 4-week dosing interval than the 2-week one, with no apparent clinical ramifications for these differences. Trough concentrations were above the lower end of the therapeutic range, even at the first injection. Long-term use up to 6 years indicated no additional accumulation. The impact of smoking and sex was similar, but less pronounced than for oral olanzapine.

Clinical pharmacology of atypical antipsychotics: an update

This review will concentrate on the clinical pharmacology, in particular pharmacodynamic data, related to atypical antipsychotics, clozapine, risperidone, paliperidone, olanzapine, que¬tiapine, amisulpride, ziprasidone, aripiprazole, asenapine, iloperidone, lurasidone and cariprazine. A summary of their acute pharmacokinetics properties are also reported. Four new second-generation antipsychotics are available: iloperidone, asenapine, lurasidone and in the next future cariprazine. Similar to ziprasidone and aripiprazole, these new agents are advisable for the lower propensity to give weight gain and metabolic abnormalities in comparison with older second-generation antipsychotics such as olanzapine or clozapine. Actually lurasidone seems to be best in terms of minimizing unwanted alterations in body weight and metabolic variables. Therapeutic drug monitoring is not strictly necessary for all of the new antipsychotic drugs because there are no unequivocal data supporting a relationship between plasma drug levels and clinical outcomes or side effects. The exception can be represented by clozapine for which plasma levels of 350-420 ng/ml are reported to be associated with an increased probability of a good clinical response. Also for olanzapine an established therapeutic range (20-50 ng/ml) is proposed to yield an optimal response and minimize side effects.

Pharmacokinetics, tolerability and safety of aripiprazole once-monthly in adult schizophrenia: an open-label, parallel-arm, multiple-dose study

This 24-week, open-label, Phase Ib, parallel-arm, multiple-dose trial assessed the pharmacokinetics, safety and tolerability of a once-monthly injection of aripiprazole (aripiprazole once-monthly) in 41 subjects with schizophrenia. The objective was to determine if aripiprazole plasma concentrations (at doses of 200, 300 and 400mg) were within the therapeutic range observed for the oral tablet (10-30 mg). Completion rates were 36.4% (n=4/11), 50.0% (n=8/16) and 71.4% (n=10/14) for the 200mg, 300 mg and 400mg groups, respectively. Patients were stabilized on oral aripiprazole (10mg/day) before the first injection and received oral aripiprazole (10mg/day) concomitantly with the first dose of aripiprazole once-monthly for 14 days. Administration of aripiprazole once-monthly at doses of 300 and 400mg provided sustained mean aripiprazole plasma concentrations comparable with the concentration range observed following multiple consecutive daily doses of oral aripiprazole. In contrast, plasma concentrations following administration of aripiprazole once-monthly at a dose of 200mg were below the therapeutic range and pharmacokinetic parameters were not proportional to the administered dose compared with the 300 mg and 400mg doses. Treatment with aripiprazole once-monthly, at any dose, did not result in any clinically meaningful changes from baseline in extrapyramidal symptom scales, clinical laboratory tests, vital signs, or electrocardiogram parameters. The most common treatment-emergent adverse events were vomiting (13.3%, 300 mg; 14.3%, 400mg), injection site pain (28.6%, 400mg), upper respiratory tract infection (10%, 200mg; 6.7% 300 mg; 14.3%, 400mg) and tremor (6.7%, 300 mg; 21.4%, 400mg). In conclusion, aripiprazole once-monthly at doses of 300 and 400mg is a viable formulation for treatment of adults with schizophrenia.

Drug safety evaluation of olanzapine pamoate

INTRODUCTION

Olanzapine pamoate is one of three second-generation antipsychotics available as depot medication. While non-adherence is a major problem in the treatment of schizophrenia, olanzapine pamoate can improve adherence, though its use is limited by its safety profile.

AREAS COVERED

The review covers data on efficacy with a focus on tolerability and safety of olanzapine pamoate using the known databases including PubMed, Psychinfo and Embase using keywords. Relevant websites were also reviewed.

EXPERT OPINION

Olanzapine is an efficacious antipsychotic that can be used in its oral and depot formula (olanzapine pamoate) for the treatment of patients with schizophrenia. It has demonstrated superiority over conventional and some other atypical antipsychotics, with both formulas having comparable low rates of motor side effects. The side effects on body weight and glucose homeostasis are also similar in both formulas and limit its use. The only clear difference regarding side effects is 'the risk that 0.07% of injections in preclinical trials have led to a post-injection delirium/sedation syndrome event which requires a risk management plan'. Especially in outpatients this could cause inconveniences that should be overcome by offering, for example, psychological therapies or psychoeducation to effectively use the time when patients have to remain in the healthcare facilities.

A review of paliperidone palmitate

Risperidone long-acting injection (RLAI) was the first second-generation antipsychotic available as a long-acting injection. Paliperidone (9-hydroxyrisperidone) is the active metabolite of risperidone, introduced initially as an extended release oral (ORal Osmotic System, OROS®, Alza Corporation) formulation (Invega®, Janssen). Paliperidone long-acting injection (PLAI) has now been developed as a suspension of paliperidone palmitate nanocrystals in an aqueous formulation (Invega Sustenna®, Xeplion®), administered monthly by intramuscular injection (deltoid or gluteal). Doses of PLAI can be expressed either in milligram equivalents (mg eq) of paliperidone palmitate or in milligrams of the active fraction of paliperidone. The recommended initiation regimen of 150 mg eq (234 mg) on day 1 and 100 mg eq (156 mg) on day 8 (both administered in the deltoid) achieves therapeutic blood levels rapidly and without the necessity of oral supplementation. No refrigeration or reconstitution prior to administration is required. PLAI has been shown in to be effective in controlling the acute symptoms of schizophrenia as well as delaying time to relapse. Safety and tolerability are comparable to RLAI with no new safety signals. Thus, PLAI may represent the rational development of RLAI with greater ease of use.

Long-acting injectable formulations of antipsychotic drugs for the treatment of schizophrenia

Antipsychotic drugs have been used to treat patients with schizophrenia and other psychotic disorders. Long-acting injectable antipsychotic drugs are useful for improving medication compliance with a better therapeutic option to treat patients who lack insight or adhere poorly to oral medication. Several long-acting injectable antipsychotic drugs are clinically available. Haloperidol decanoate and fluphenazine decanoate are first-generation depot drugs, but the use of these medicines has declined since the advent of second-generation depot agents, such as long-acting risperidone, paliperidone palmitate, and olanzapine pamoate. The second-generation depot drugs are better tolerated and have fewer adverse neurological side effects. Long-acting injectable risperidone, the first depot formulation of an atypical antipsychotic drug, was prepared by encapsulating risperidone into biodegradable microspheres. Paliperidone palmitate is an aqueous suspension of nanocrystal molecules, and olanzapine pamoate is a microcrystalline salt of olanzapine and pamoic acid suspended in aqueous solution. This review summarizes the characteristics and recent research of formulations of each long-acting injectable antipsychotic drug.

Patients' and clinicians' attitude towards long-acting depot antipsychotics in subjects with a first episode of psychosis

OBJECTIVES

The acceptance and use of long-acting depot antipsychotics has been shown to be influenced by the attitudes of patients and clinicians. Depot treatment rates are low across countries and especially patients with first-episode psychosis are rarely treated with depot medication. The aim of this article was to review the literature on patients' and clinicians' attitudes towards long-acting depot antipsychotics in subjects with first-episode psychosis.

METHODS

A systematic search of Medline, Embase, PsycINF and Google Scholar was conducted. Studies were included if they reported original data describing patients' and clinicians' attitudes towards long-acting depot antipsychotic in subjects with first-episode psychosis.

RESULTS

Six studies out of a total of 503 articles met the inclusion criteria. Four studies conveyed a negative and two a positive opinion of clinicians toward depot medication. No systematic study directly addressed the attitude of patients with first-episode psychosis. Psychiatrists frequently presume that patients with first-episode psychosis would not accept depot medication and that depots are mostly eligible for chronic patients.

CONCLUSIONS

Full information of all patients especially those with first episode psychosis in a therapeutic relationship that includes shared decision-making processes could reduce the negative image and stigmatization attached to depots.

Efficacy of olanzapine long-acting injection in patients with acutely exacerbated schizophrenia: an insight from effect size comparison with historical oral data

BACKGROUND

To treat acute schizophrenia, a long-acting injectable antipsychotic needs a rapid onset of action and therapeutic profile similar to that of oral agents. The present post-hoc analyses compared results from a randomized, double-blind, placebo-controlled trial of olanzapine long-acting injection (LAI) for acute schizophrenia with those observed in similarly designed trials of oral olanzapine.

METHODS

Six-week results from the olanzapine LAI study (N = 404) were compared with those of 3 oral studies (study 1: olanzapine vs. haloperidol vs. placebo [N = 335]; study 2: olanzapine vs. haloperidol vs. low-dose olanzapine [N = 431]; study 3: olanzapine vs. placebo vs. low-dose olanzapine [N = 152]). All patients had baseline Brief Psychiatric Rating Scale (BPRS) scores ≥24 (0-6 scale). Six-week effect sizes were calculated. Efficacy onset, pharmacokinetics, discontinuations, weight gain, and extrapyramidal symptoms were also assessed.

RESULTS

At 6 weeks, mean BPRS scores decreased by 14 to 15 points for olanzapine LAI (405 mg/4 weeks, 210 or 300 mg/2 weeks), by 8 to 16 for oral olanzapine (10 ± 2.5 or 15 ± 2.5 mg/day), and by 12 to 13 for haloperidol (15 ± 5 mg/day). For those same dose groups, effect sizes vs. placebo for the BPRS were 0.7 to 0.8 for olanzapine LAI, 0.5 to 0.7 for oral olanzapine, and 0.6 for haloperidol. The first statistically significant separation from placebo on the BPRS occurred at 3 days for the olanzapine LAI groups and at 1 week for oral olanzapine and haloperidol (15 ± 5 mg/day) in oral study 1 although as late as week 6 for the 10-mg/day olanzapine dose in oral study 3. Olanzapine concentrations were similar across studies. Weight gain ≥7% of baseline occurred in up to 35% of olanzapine LAI and oral patients versus up to 12% of haloperidol and placebo patients. Extrapyramidal symptoms were lowest in the olanzapine LAI groups and significantly greater in the haloperidol groups. No post-injection delirium/sedation syndrome events occurred in the olanzapine LAI study.

CONCLUSIONS

Patients treated acutely with olanzapine LAI showed a similar pattern of improvement to that seen historically with oral olanzapine. With the exception of injection-related adverse events, the efficacy and tolerability profile of olanzapine LAI is similar to oral olanzapine.

TRIAL REGISTRATION

ClinicalTrials.gov ID; URL: http://http//www.clinicaltrials.gov/: NCT00088478; ClinicalStudyResults.org ID; URL: http://www.clinicalstudyresults.org/: 917, 978, 982, and 5984.

[Informed Consent and the Approval by Ethics Committees of Studies Involving the Use of Atypical Antipsychotics in the Management of Delirium]

INTRODUCTION

Delirium is an acute alteration of consciousness and cognition. Atypical antipsychotics (AA) have recently become a main part of its treatment. Studies in this population generate a series of ethical dilemmas concerning the voluntary participation of patients and their state of vulnerability since their mental faculties are, by definition, compromised.

OBJECTIVE

To assess whether studies with AA for the treatment of delirium obtained an approval by an ethics committee on human research (ECHR), if an informed consent (IC) was obtained, whether the IC was verbal or written, and who gave the approval to participate.

METHOD

Systematic review of Medline for studies of delirium where quetiapine and olanzapine were the main treatment, assessing the existence of an ECHR approval and implementation of an IC.

RESULTS

11 studies were identified (6 of quetiapine and 5 of olanzapine). 5 had an ECHR approval.

CONCLUSIONS

Most studies examining the treatment of delirium with quetiapine or olanzapine were not subject to approval by an ECHR and most of them did not obtain an IC from the patient's legal guardian. It is essential that future studies of antipsychotics and other drugs for the treatment of delirium have the protocol approved by an ECHR and a written IC signed by the patient's legal representative, since by definition delirium is a condition that compromises superior mental processes.

The Potential Role of Long-acting Injectable Antipsychotics in People with Schizophrenia and Comorbid Substance Use

OBJECTIVE: Treatment of schizophrenia in patients with comorbid substance use (alcohol/illicit drug use, abuse or dependence) presents challenges for public health systems. Substance use in people with schizophrenia is up to four times greater than the general population and is associated with medication nonadherence and poor outcomes. Therefore, continuous antipsychotic treatment in this population may pose more of a challenge than for those with schizophrenia alone. Many clinical trials and treatment recommendations in schizophrenia do not take into consideration substance use as people with comorbid substance use have typically been excluded from most antipsychotic trials. Nonetheless, antipsychotic treatment appears to be as efficacious in this population, although treatment discontinuation remains high. The objective of this review was to highlight the importance and utility of considering long-acting injectable antipsychotics for patients with schizophrenia and comorbid substance use. METHODS: We did a literature search using PubMed with key words schizophrenia and substance use/abuse/dependence, nonadherence, antipsychotics, long acting injectables, relapse, and psychosocial interventions. We limited our search to human studies published in English and 4,971 articles were identified. We focused on clinical trials, case reports, case series, reviews and meta-analyses resulting in 125 articles from 1975-2011. RESULTS: Our review suggests the potential role of long-acting injectables for people with comorbid substance use and schizophrenia in leading to improvements in psychopathology, relapse prevention, fewer rehospitalizations, and better outcomes. CONCLUSIONS: While more research is needed, long-acting antipsychotics should be considered an important option in the management of people with schizophrenia and comorbid substance use.

Oral versus Long-Acting Injectable Antipsychotics in the Treatment of Schizophrenia and Special Populations at Risk for Treatment Nonadherence: A Systematic Review

Long-acting injectable antipsychotics (LAIs) should offer better efficacy and tolerability, compared to oral antipsychotics due to improved adherence and more stable pharmacokinetics. However, data on LAIs has been mixed, with some studies finding that they are more effective and tolerable than oral antipsychotics, and others finding the contrary. One possibility for the disparate results may be that some studies administered different antipsychotics in the oral and injectable form. The present systematic review examined the efficacy and tolerability of LAIs versus their oral equivalents in randomized and naturalistic studies. In addition, it examined the impact of LAIs on special populations such as patients with first-episode psychosis, substance use disorders, and a history of violence or on involuntary outpatient commitment. Randomized studies suggest that not all LAIs are the same; for example, long-acting risperidone may be associated with equal or less side effects than oral risperidone, whereas fluphenazine decanoate and enanthate may be associated with equal or more side effects than oral fluphenazine. They also suggest that LAIs reduce risk of relapse versus oral antipsychotics in schizophrenia outpatients when combined with quality psychosocial interventions. For their part, naturalistic studies point to a larger magnitude of benefit for LAIs, relative to their oral equivalents particularly among first-episode patients.

Patient and Health Care Provider Perspectives on Long Acting Injectable Antipsychotics in Schizophrenia and the Introduction of Olanzapine Long-Acting Injection

Olanzapine long acting injection has joined risperidone and paliperidone as the second generation long acting antipsychotic injection options for treatment of patients with schizophrenia. Long acting injections are important alternatives to oral medications for patients who have difficulty adhering to daily or multiple daily medication administrations, yet may be underutilized or not well understood. Patient perceptions, adherence, and preferences are important issues for health care providers to address when discussing treatment options with their patients. Reviewed here are overall patient and health care provider attitudes and perceptions regarding long acting injections and the details of olanzapine long acting injectable, the newest agent, and how it will fit in the marketplace. In addition, efficacy, safety, dosing and use data regarding this newest long acting agent are reviewed and compared to other available long acting agents.