Switching to long-acting injectable antipsychotics: pharmacological considerations and practical approaches

INTRODUCTION

Long-acting injectable antipsychotics (LAIs) are an effective, but potentially underutilized treatment option in schizophrenia and other severe mental illnesses. Prescribing information typically focuses on how to initiate treatment from the corresponding oral formulations. However, in clinical practice other scenarios, such as switching from other oral antipsychotics or other LAIs, occur frequently, requiring guidance.

AREAS COVERED

Pharmacodynamic properties of antipsychotics and their relation to rebound symptoms. Pharmacokinetic properties of LAIs and their implications for switching approaches. Specific approaches to switching to LAIs.

EXPERT OPINION

The LAI landscape has evolved significantly in the last decade with more formulations available, longer dosing intervals, and extended indications. However, currently available LAIs have various shortcomings, e.g. short dosing intervals, need for oral supplementation, loading regimens, deep intramuscular injection and/or restricted indications. Recent improvements include a one-day initiation option for aripiprazole lauroxil, aripiprazole monohydrate once-monthly, risperidone in situ microparticles and subcutaneous risperidone. Future LAI developments should focus on longer dosing intervals, subcutaneous administration, expansion of LAIs beyond currently available antipsychotic agents and indications beyond schizophrenia and bipolar disorder. In the future, LAIs might become a first-line treatment after initial oral stabilization for chronic mental disorders with need for maintenance treatment and presence of significant non-adherence.

Risk of Drug-induced Movement Disorders with Newer Antipsychotic Agents

Background:

The last decade has seen development of numerous novel antipsychotic drugs with unique mechanisms including long-acting formulations for clinical use. A comparative assessment of these new drugs with each other and previous antipsychotics have not been performed with regards to risk for drug-induced movement disorders (DIMD).

Methods:

Medline was searched from January 2010 to February 2022 for primary research articles and review articles in English using the search terms “extrapyramidal” and “tardive” with individual drug names of novel antipsychotics.

Results:

We identified articles describing the risk of DIMD with 6 novel antipsychotics, 4 novel formulations, and 3 experimental antipsychotics. Both short- and long-term data generally showed comparable to lower risk of DIMD with novel antipsychotics and recent long-acting formulations compared to previously marketed antipsychotics.

Discussion:

Several novel antipsychotics, particularly lumateperone and pimavanserin, show promise in being able to treat psychosis while reducing the risk of DIMD. Long-acting paliperidone may reduce risk of DIMD while other long-acting injectable formulations of SGA have similar risk of DIMD compared to oral formulations. New drug targets for treating psychosis without dopamine blockade also show promise.

Aripiprazole Lauroxil Dosing Regimens: Understanding Dosage Strengths and Injection Intervals

Aripiprazole lauroxil (AL) is a long-acting atypical antipsychotic approved for the treatment of schizophrenia in adults. AL has five regimen options that offer three different injection intervals using four different dosage strengths. The relationship between dosage strength (milligram injected), injection interval (time between injection visits), and expected steady-state plasma aripiprazole concentrations may not be readily apparent. This article illustrates the relationship by providing visual scenarios of steady-state plasma aripiprazole concentrations for the five AL regimens. The efficacy of AL was originally demonstrated in a pivotal study of two AL regimens (approved as 441 mg monthly and 882 mg monthly). The three additional regimens (662 mg monthly, 882 mg every 6 weeks, and 1064 mg every 2 months) were approved based on pharmacokinetic bridging studies and population pharmacokinetic models. For this paper, expected steady-state concentrations for each AL regimen were derived from the published population pharmacokinetic models and compared using median values and ranges. The five labeled AL regimens differ in dosage strength and injection interval; however, model-simulated concentrations illustrate that each regimen produces steady-state plasma aripiprazole concentrations within the upper and lower bounds associated with known efficacy for AL 441 mg and 882 mg administered monthly. This visual presentation of the relationship between dosage strength of the AL injection, the interval between successive injections, and steady-state aripiprazole plasma concentrations may demonstrate for clinicians how dosage strength and injection interval can be considered in selecting the AL regimen option that best fits the clinical circumstances of the individual patient.

Bioequivalence of 2 Aripiprazole Orally Disintegrating Tablets in Healthy Chinese Volunteers Under Fasting and Fed Conditions

To assess the bioequivalence of 2 formulations of aripiprazole orally disintegrating tablets and to monitor their safety and tolerability in Chinese subjects, a single-site, open-label, randomized, 2-preparation, single-dose, 2-period crossover design was conducted. All 60 subjects were randomly divided into the fasting group and the fed group. Blood samples were collected at scheduled times after a single oral dose of orodispersible tablets containing 10 mg of aripiprazole. In the fasting state, the geometric mean ratios (90% confidence intervals [CIs]) of the test/reference formulation were 92.22%-100.20% for the area under the concentration-time curve (AUC) from time zero to the last measured concentration (AUC_0-t ), 91.73%-100.14% for the AUC from administration to infinite time (AUC_0-∞ ), and 98.52%-112.52% for the maximum plasma concentration (C_max ). In the fed state, AUC_0-t , AUC_0-∞ , and C_max were 92.23%-100.20%, 91.73%-100.14%, and 95.91%-105.13%, respectively. The 90%CIs of the test/reference AUC ratio and C_max ratio were within the acceptance range of 80.00%-125.00% for bioequivalence. Neither the maximum peak plasma concentration (t_max ) nor the terminal elimination half-life (t_1/2 ) showed any significant difference. No serious adverse events) were encountered during the study. The test and reference formulations were bioequivalent under both fasting and fed conditions and were found to be safe and tolerated.

Long-Acting Formulations: A Promising Approach for the Treatment of Chronic Diseases

Medication and patient adherence are the two main aspects of any successful treatment of chronic disease. Even though diseases and its treatment existed for several hundred years, the treatment optimization for a given patient is still a researcher question for scientists. There are differences in treatment duration, prognostic signs and symptoms between patient to patient. Hence, designing ideal formulation to suit individual patient is a challenging task. The conventional formulations like oral solids and liquids gives a partial or incomplete treatment because the patient needs to follow the daily pills for a longer time. In such cases, the long-acting formulations will have better patient compliances as drug will be released for a longer duration. Many such approaches are under the clinical investigation. The favorable pharmacokinetic and pharmacodynamic relationships, will be promising option for the treatment of chronic diseases. In this review, we have highlighted the importance of long-acting formulations in the treatment of chronic diseases and the advent of newer formulation technologies.

Aripiprazole IM depot as an option for the treatment of bipolar disorder

Introduction: Long-acting injectable (LAI) antipsychotic drugs are developed to reduce daily intake need and to overcome treatment non-adherence. Aripiprazole IM depot refers to two long-acting aripiprazole formulations, once monthly monohydrate (AOM) and aripiprazole lauroxil. AOM has been approved for schizophrenia since 2012 and for bipolar disorder since 2017. Aripiprazole lauroxil is approved for schizophrenia, not for bipolar disorder.Areas covered: To assess the effect of AOM in bipolar disorder, the authors searched PubMed and ClinicalTrials.gov for randomized trials using AOM in patients with bipolar disorder. Included were four studies covering efficacy, functioning, quality of life, and safety/tolerability. Studies lasted 12 months.Expert opinion: AOM reduced symptoms of patients with bipolar disorder and a manic episode, increased functioning and quality of life, and protected from recurrence of manic episodes. It proved to be safe/tolerable, with only akathisia occurring in ≥10% of cases and more frequently than with placebo. However, there were only 143 patients receiving AOM in the considered studies. Included studies were backed in their conclusions by other literature, but they come from 2017-2018. No studies are expected or planned in the near future. Aripiprazole lauroxil has not applied for approval in bipolar disorder and there is no sign it will.

Long-acting injectable antipsychotics: what, when, and how

Current guidelines for the treatment of patients with schizophrenia advocate that patients receive treatment with a long-acting injectable (LAI) antipsychotic medication if they prefer such treatment or if they have a history of poor or uncertain adherence. Available LAI formulations in the United States include first-generation antipsychotics (fluphenazine decanoate and haloperidol decanoate), risperidone/paliperidone containing products (risperidone microspheres, paliperidone palmitate, and risperidone subcutaneous), aripiprazole containing products (aripiprazole monohydrate and aripiprazole lauroxil), and olanzapine pamoate. LAI antipsychotics can address the guesswork about adherence status and patients may prefer them if they are offered this as a choice, including individuals early in their disease course. Additional approved indications in the United States for LAI antipsychotics include bipolar I disorder maintenance treatment for risperidone microspheres and aripiprazole monohydrate, and schizoaffective disorder for paliperidone palmitate once monthly. Differences and similarities among the different products are discussed, including guidance regarding optimal treatment selection. Tips are provided to enhance effective patient communication to maximize the likelihood of acceptance of this treatment modality.

Specific Anti-hostility Effects of Atypical Antipsychotics in Persons with Schizophrenia: From Clozapine to Cariprazine

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to:• Evaluate the anti-hostility effects of available atypical antipsychotic agents.

ABSTRACT

In addition to hallucinations and delusions, persons with schizophrenia may exhibit hostility. In clinical trials of antipsychotics, hostility is routinely measured as part of rating scales such as the Brief Psychiatric Rating Scale or Positive and Negative Syndrome Scale. The availability of the atypical antipsychotic clozapine in 1989 led to the observation that it is possible to have a treatment effect on hostility that is independent of the treatment effect on hallucinations or delusions, and independent of general sedative effects. The data supporting this notion of a specific anti-hostility effect are the most robust for clozapine as the data include specifically designed randomized, controlled clinical trials. A specific anti-hostility effect is also observable to various degrees with most of the other atypical antipsychotics, as evidenced in post hoc analyses of clinical trials originally conducted for regulatory purposes, supplemented by post hoc analyses of large effectiveness trials. The generalizability of these studies, however, may be limited. Participants in these trials were not selected for aggressive and hostile behavior. Some of the studies also excluded patients with substance use disorders. The latter is particularly important because alcohol and substance use are well known to increase risk for hostility and aggression. Nevertheless, the repeated demonstrations of the specificity of an anti-hostility effect (in terms of statistical independence of effects on other positive symptoms and of sedation) are of potential clinical importance.

Schizophrenia; A Review on Promising Drug Delivery Systems

Background:

Schizophrenia belongs to mental illnesses affecting 1% of the worldwide population. Its therapy is still unmet; thus, researchers aimed to develop new pharmacological molecules which can improve its management.

Methods:

Moreover, the current typical and atypical antipsychotics should be formulated in more efficacious systems that can deliver the drug in the brain with as few side effects as possible. Further, the development of long-acting efficient drug delivery systems could be significant in minimizing frequent dosing which is nonpreferred to schizophrenics.

Results:

Herein, authors focused on current developments of antipsychotic medications used in schizophrenia management. Various studies, which include the use of first and second-generation antipsychotics, were analyzed according to their efficacy. In fact, in this review, oral, injectable, transdermal and intranasal formulations entrapped antipsychotics are presented to be valuable guidance for scientists to formulate more effective drug delivery systems for schizophrenic patients.

Conclusions:

This review aimed to assist researchers working on schizophrenia management by summarizing current medications and newly synthesized drug delivery systems recently found in the literature.

Metabolism of bioconjugate therapeutics: why, when, and how?

Bioconjugation of therapeutic agents has been used as a selective drug delivery platform for many therapeutic areas. Bioconjugates are prepared by the covalent linkage of active compounds (small or large molecule) to a carrier molecule (lipids, proteins, peptides, carbohydrates, and polymers) through a chemical linker. The linkage of the active component to a carrier molecule enhances the therapeutic window through a targeted delivery and by reducing toxicity. Bioconjugates also possess improved pharmacokinetic properties such as a long half-life, increased stability, and cleavage by intracellular enzymes/environment. However, premature cleavage of the bioconjugates and the resulting metabolites/catabolites may produce undesirable toxic effects and, hence, it is critical to understand cleavage mechanisms, metabolism of bioconjugates, and translatability to human in the discovery stages. This article provides a comprehensive overview of linker cleavage pathways and catabolism/metabolism of antibody-drug conjugates, glycoconjugates, polymer-drug conjugates, lipid-drug conjugates, folate-targeted small molecule-drug conjugates, and drug-drug conjugates.

Practical considerations for managing breakthrough psychosis and symptomatic worsening in patients with schizophrenia on long-acting injectable antipsychotics

With more long-acting injectable (LAI) antipsychotics available for treating schizophrenia, each with variable durations of action (2 weeks to 3 months), it is important to have clear management strategies for patients developing breakthrough psychotic symptoms or experiencing symptomatic worsening on LAIs. However, no treatment guidelines or clinical practice pathways exist; health-care providers must rely on their own clinical judgment to manage these patients. This article provides practical recommendations-based on a framework of clinical, pharmacokinetic, and dosing considerations-to guide clinicians' decisions regarding management of breakthrough psychotic symptoms. Management options include ruling out/addressing medical illness or substance abuse/misuse as a contributing factor, addressing stressors, optimizing nonpharmacologic treatments, treating medical/psychiatric comorbidities, ensuring proper LAI administration technique, addressing missed LAI doses or lack of steady-state attainment, and increasing LAI dose directly or indirectly by shortening the injection interval (off-label). If these strategies do not work sufficiently with frequent monitoring, the LAI could be supplemented with a low dose of the corresponding oral formulation for fast symptom control (off-label). However, caution should be exercised with this strategy, because data on the safety of concomitant use of LAI and oral antipsychotics (OAPs) are limited, especially over extended periods. If symptoms abate, therapy optimization could be continued and slow discontinuation of the OAP could be considered. For persistent/worsening symptoms, the OAP should be increased to optimum effective dose while intensifying the initial steps used before it was added. If this fails, switching the OAP or LAI could be considered. We believe that these strategies will help clinicians manage breakthrough psychotic symptoms during LAI treatment and improve overall outcomes among those who can benefit from LAIs.

Switching patients with schizophrenia from paliperidone palmitate to aripiprazole lauroxil: A 6-month, prospective, open-label study

We assessed the effectiveness of switching from paliperidone palmitate (PP) or risperidone long-acting injection (RLAI) to aripiprazole lauroxil (AL). Prospective, 6-month study in patients with schizophrenia with residual symptoms or intolerance with PP/RLAI. Effectiveness assessed via all-cause and medication-related discontinuation; CGI-S/BPRS and adverse event monitoring assessed efficacy/tolerability, respectively. Fifty-one patients (n = 50 PP; n = 1 RLAI) enrolled; 35 completed the study. All-cause and medication-related discontinuation was 30% and 9% over 6 months, respectively. CGI-S/BPRS improved significantly in those continuing treatment. Adverse events were generally mild to moderate. Patients with efficacy or tolerability concerns with PP/RLAI can be switched to AL.

Best Practices for Aripiprazole Lauroxil Administration: From Formulation Development to Injection Technique

Long-acting injectable (LAI) antipsychotics are an important treatment option for patients with schizophrenia. Advances and variability in formulation technology have provided several LAI antipsychotic treatment options for schizophrenia, with a wide range of doses and dose intervals. However, clinical reviews of LAIs have not focused on formulation development despite its clinical relevance to injection safety and technique. This article reviews the relationship between formulation technology and clinical practices for LAIs, with a focus on aripiprazole lauroxil, a long-acting atypical antipsychotic indicated for the treatment of schizophrenia. The formulation developed for aripiprazole lauroxil is an aqueous-based suspension suitable for use as a prefilled syringe that, after injection, will release aripiprazole slowly into the plasma. The clinical relationship between the aripiprazole lauroxil formulation and proper injection techniques is explained, including why tapping and shaking the syringe to resuspend the drug particles and rapid injection speed are key steps for best injection practices for this formulation.

Effect of aripiprazole lauroxil in patients with acute schizophrenia as assessed by the Positive and Negative Syndrome Scale-supportive analyses from a Phase 3 study

OBJECTIVE

Aripiprazole lauroxil (AL) is a long-acting injectable atypical antipsychotic that was evaluated for the treatment of schizophrenia in a randomized, placebo-controlled, Phase 3 study. Here, we present exploratory analyses of supportive efficacy endpoints.

METHODS

Patients experiencing an acute exacerbation of schizophrenia received AL 441 mg intramuscularly (IM), AL 882 mg IM, or matching placebo IM monthly. Supportive endpoints included changes from baseline at subsequent time points in Clinical Global Impression-Severity (CGI-S) scale score; Positive and Negative Syndrome Scale (PANSS) Total score; PANSS Positive, Negative, and General Psychopathology subscale scores; PANSS Marder factors (post hoc); and PANSS responder rate. Overall response rate, based on PANSS Total score and Clinical Global Impression-Improvement (CGI-I) scale score, was also analyzed.

RESULTS

Of 622 patients who were randomized, 596 had ≥1 post-baseline PANSS score. Patients were markedly ill at baseline (mean PANSS Total scores 92-94). Compared with placebo, CGI-S scores; PANSS Positive, Negative, and General Psychopathology subscale scores; and PANSS Marder factors were all significantly (p<0.001) improved by Day 85 with both AL doses, with significantly lower scores starting from Day 8 in most instances. Treatment response rates were significantly (p<0.001) greater with both doses of AL vs placebo.

CONCLUSION

AL demonstrated robust efficacy on CGI-S score, PANSS subscale scores, PANSS Marder factors, and response rates. Study limitations included use of a fixed dose for initial oral aripiprazole and fixed monthly AL doses without the option to individualize the oral initiation dosing or injection frequency for efficacy, tolerability, or safety.

Improving long-term subcutaneous drug delivery by regulating material-bioenvironment interaction

Subcutaneous long-acting release (LAR) formulations have been extensively developed in the clinic to increase patient compliance and reduce treatment cost. Despite preliminary success for some LAR systems, a major obstacle limiting the therapeutic effect remains on their interaction with surrounding tissues. In this review, we summarize how living bodies respond to injected or implanted materials, and highlight some typical strategies based on smart material design, which may significantly improve long-term subcutaneous drug delivery. Moreover, possible strategies to achieve ultra-long (months, years) subcutaneous drug delivery systems are proposed. Based on these discussions, we believe the well-designed subcutaneous long-acting formulations will hold great promise to improve patient quality of life in the clinic.

Paliperidone palmitate once-monthly maintains improvement in functioning domains of the Personal and Social Performance scale compared with placebo in subjects with schizoaffective disorder

OBJECTIVE

Evaluate the effect of paliperidone palmitate once-monthly (PP1M) injectable on the specific functioning domains of the Personal and Social Performance (PSP) scale in patients with schizoaffective disorder (SCA) participating in a long-term study.

METHODS

This study (NCT01193153) included both in- and outpatient subjects with SCA experiencing an acute exacerbation of psychotic and mood symptoms. Subjects were treated with PP1M either as monotherapy or in combination with antidepressants or mood stabilizers during a 25-week open-label (OL) phase. Stabilized subjects were randomly assigned 1:1 (PP1M or placebo) into a 15-month double-blind (DB) relapse-prevention period. Functioning of the randomized subjects during OL and DB phases was evaluated using the PSP scale (four domains: socially useful activities, personal/social relationships, self-care, and disturbing/aggressive behaviors). Three statistical approaches were utilized to analyze PSP scores to assess robustness and consistency of findings. No adjustments were made for multiplicity.

RESULTS

334 of 667 enrolled subjects were stabilized with PP1M, randomly assigned to PP1M (n=164) or placebo (n=170) in the DB phase, and included in this analysis. Improvements in all PSP domain scores were observed during the OL phase and were maintained during the DB phase with PP1M, but decreased with placebo. Differences compared to placebo were significant in all four PSP domains during the DB phase (P≤0.008).

CONCLUSION

The analysis in this study showed that PP1M improves functioning, as measured by the four PSP domain scores, in symptomatic subjects with SCA. Functioning was maintained compared with placebo.

Aripiprazole Lauroxil: Pharmacokinetic Profile of This Long-Acting Injectable Antipsychotic in Persons With Schizophrenia

BACKGROUND

Aripiprazole lauroxil is an extended-release prodrug of aripiprazole for intramuscular injection, approved for schizophrenia treatment. We developed a population pharmacokinetic (PopPK) model to characterize aripiprazole lauroxil PK and evaluate dosing scenarios likely to be encountered in clinical practice.

METHODS

Data from 616 patients with schizophrenia, collected from 5 clinical studies, were used to construct the PopPK model. The model was subsequently used to evaluate various dose levels and frequency and the impact of dosing delay on aripiprazole concentrations.

FINDINGS

The results of the model indicate that aripiprazole is released into the systemic circulation after 5 to 6 days, and release continues for an additional 36 days. The slow increase in aripiprazole concentration after injection necessitates the coadministration of oral aripiprazole for 21 days with the first injection. Based on the PopPK model simulations, a dosing interval of 882 mg every 6 weeks results in aripiprazole concentrations that fall within the concentration range associated with the efficacious aripiprazole lauroxil dose range (441-882 mg dosed monthly). A 662-mg monthly dose also resulted in aripiprazole concentrations within the efficacious dose range. Aripiprazole lauroxil administration results in prolonged exposure, such that dose delays of 2 to 4 weeks, depending on the dose regimen, do not require oral aripiprazole supplementation upon resumption of dosing.

CONCLUSIONS

This PopPK model and model-based simulations were effective means for evaluating aripiprazole lauroxil dosing regimens and management of missed doses. Such analyses play an important role in determining the use of this long-acting antipsychotic in clinical practice.

Morphological and Crystalline Transitions in Monohydrous and Anhydrous Aripiprazole for a Long-Acting Injectable Suspension

Many formulation and manufacturing processes can lead to morphological and crystalline transitions in many polycrystalline drugs, changing the properties of active pharmaceutical ingredients (APIs) such as solubility and physical stability which influence their therapeutic effects and safety and so limit their usefulness. Here, we report significant changes in crystal forms and morphology, including the shape and size of particles during the manufacture of off-white aripiprazole (APZ) dry powders used for long-acting and injectable suspensions. With the optimal top-down approach, powders were prepared by recrystallizing uniform monohydrous APZ (MA) and polycrystalline anhydrous APZ (AA) form III, characterized by thermal analysis, PXRD, and FT-IR. However, powders involving MA (MAP) with a lower mean size (2.126 μm), narrower distribution (span = 1.90), and higher stability compared with AA dry powders (AAP) were found to exhibit dehydration behavior and morphological changes after completion of the preparation processes based on the results of thermal analysis. In the case of APZ powders, we wished to obtain more information to guide in the industrial production and experimental design of suspensions in the future.

Emerging pharmacological therapies in schizophrenia: what's new, what's different, what's next?

There are several new and emerging medication interventions for both the acute and maintenance treatment phases of schizophrenia. Recently approved are 2 new dopamine receptor partial agonists, brexpiprazole and cariprazine, as well as 2 new long-acting injectable antipsychotic formulations, aripiprazole lauroxil and 3-month paliperidone palmitate. Although differences in efficacy compared to other available choices are not expected, the new oral options offer different tolerability profiles that may be attractive for individual patients who have had difficulties with older medications. The new long-acting injectable options provide additional flexibility in terms of increasing the time interval between injections. In Phase III of clinical development is a novel antipsychotic, lumateperone (ITI-007), that appears to have little in the way of significant adverse effects. Deutetrabenazine and valbenazine are agents in Phase III for the treatment of tardive dyskinesia, a condition that can be found among persons receiving chronic antipsychotic therapy. On the horizon are additional injectable formulations of familiar antipsychotics, aripiprazole and risperidone, that may be more convenient than what is presently available.