Pharmacokinetics of loxapine following inhalation of a thermally generated aerosol in healthy volunteers

Fifty years of experience with loxapine for the rapid non-coercive tranquilization of acute behavioral disturbances in schizophrenia patients, and beyond

INTRODUCTION

Acute behavioral disturbances in psychosis, including agitation, comprise a heterogeneous group of manifestations varying in intensity and duration they last for. They require rapid, non-coercive treatments ranging from verbal de-escalation to the calming effect of pharmacological agents. The treatment goals are reduction of patient suffering and prevention of disease deterioration. Stabilizing rather than sedating is preferred to ensure improved compliance and a stronger therapeutic alliance. Furthermore, animal pharmacology and clinical studies on agitation reveal the robust calming and anxiolytic properties of loxapine.

AREAS COVERED

This review covers the pharmacological and clinical history of loxapine along with research developments. It emphasizes the advantages of its multiple formulations ranging from injectable forms and tablets to orally inhaled forms to attain rapid and fine-tuned tranquilization.

EXPERT OPINION

Rapid tranquillization is achieved within 2-6 hours using liquid orally-consumed loxapine, and within an hour or less with its IM or orally inhaled forms. Loxapine has been adopted in the management of a wide range of acute disturbances, such as agitation in psychosis. In the context of personalized medicine, key cellular and molecular elements of the schizophrenia phenotype were recently shown to be improved with loxapine.

Recent advances in drug delivery to the central nervous system by inhalation

INTRODUCTION

Drugs need to enter the systemic circulation efficiently before they can cross the blood-brain barrier and reach the central nervous system. Although the respiratory tract is not a common route of administration for delivering drugs to the central nervous system, it has attracted increasing interest in recent years for this purpose.

AREAS COVERED

In this article, we compare pulmonary delivery to three other common routes (parenteral, oral, and intranasal) for delivering drugs to the central nervous system, followed by summarising the devices used to aerosolise neurological drugs. Recent studies delivering drugs for different neurological disorders via inhalation are then discussed to illustrate the strengths of pulmonary delivery.

EXPERT OPINION

Recent studies provide strong evidence and rationale to support inhaling neurological drugs. Since inhalation can achieve improved pharmacokinetics and rapid onset of action for multiple drugs, it is a non-invasive and efficient method to deliver drugs to the central nervous system. Future research should focus on delivering other small and macro-molecules via the lungs for different neurological conditions.

New Antipsychotic Medications in the Last Decade

PURPOSE OF REVIEW

Over the last ten years, the treatment of psychosis has seen a near explosion of creative development in both novel agents and new delivery modalities. The current review summarizes these developments over the past decade (2011-2020). We performed a systematic review utilizing PubMed and PsychInfo with the aim of identifying all the RCT and related analyses in adults with psychosis (schizophrenia and mania).

RECENT FINDINGS

We identified 11 significant developments: the introduction of new antipsychotics cariprazine, brexpiprazole, lumateperone, and pimavanserin; introduction of new delivery methods: subcutaneous long-acting risperidone, aripiprazole lauroxil, transdermal asenapine, and inhaled loxapine; and the introduction of new approaches such as olanzapine/samidorphan for olanzapine-associated weight gain, examination of the TAAR1 agonist SEP 363,856 as a test of concept, and the combination of Xanomeline/Trospium, an M₁ and M₄ muscarinic receptor agonist in conjunction with a peripheral anticholinergic. Last decade has seen a tremendous development in second-generation antipsychotics which provides unprecedented treatment options for clinicians in treating psychosis.

Safety and efficacy of pharmacologic agents used for rapid tranquilization of emergency department patients with acute agitation or excited delirium

Introduction: Management of patients with acute agitation or aggressive behavior can pose a significant challenge to health-care providers in emergency departments. Areas covered: This article provides a comprehensive review of the pharmacologic properties, efficacy, and safety profiles of select intramuscular (IM) sedative agents (i.e., antipsychotics, benzodiazepines, and ketamine) for rapid tranquilization. Expert opinion: Using antipsychotics and benzodiazepines - whether a single agent or combined - will have similar efficacy in producing sedation. But there are differences in the time to sedation depending on which agent is used. Based upon the available studies, droperidol (5-10 mg IM) and midazolam (5-10 mg IM) have the fastest onset of sedation when either is used as a single agent. When combination therapy is used, using midazolam with an antipsychotic agent, instead of lorazepam, may result in faster sedative effect. QT prolongation and torsades de pointes are uncommon adverse drug effects of antipsychotic administration. Ketamine is often reserved as a second-line agent when antipsychotics and benzodiazepines fail to produce the desired tranquilization. However, ketamine (5 mg/kg IM) is more frequently associated with airway compromise requiring endotracheal intubation. A low-dose of ketamine (2 mg/kg IM) may reduce the risk of airway compromise while providing adequate sedation.

Inhaled Loxapine for the Management of Acute Agitation in Bipolar Disorder and Schizophrenia: Expert Review and Commentary in an Era of Change

Agitation is a common and costly phenomenon associated with a number of psychiatric conditions including schizophrenia and bipolar disorder. Early identification and prompt intervention to relieve the symptoms of agitation are essential to avoid symptomatic escalation and emergence of aggressive behaviour. Recent consensus guidelines emphasise the need for non-coercive management strategies to protect the therapeutic alliance between patients and their healthcare providers—an alliance that is critical for the effective management of chronic psychiatric conditions. Rapid symptom relief and de-escalation of agitation are necessary to avoid the costly and traumatic use of coercive techniques of physical restraint and seclusion, which require admission and prolonged hospitalisation. Inhaled loxapine is approved for the treatment of acute agitation in patients with schizophrenia or bipolar disorder. Clinical studies have confirmed the efficacy, rapid onset of action, and safety and tolerability of this agent in the psychiatric emergency and hospital settings. Emerging data have indicated the potential for inhaled loxapine as a self-administered agent for use in the community setting without the direct supervision of a healthcare professional. We discuss the evolving treatment paradigm and the place of inhaled medications for acutely agitated patients both within and outside the emergency and hospital setting.

The discovery and development of inhaled therapeutics for migraine

INTRODUCTION

Migraine is a disabling primary headache disorder that requires effective treatments. Inhalation is currently being explored for the delivery of drugs for migraine. Pulmonary-route delivery of drugs shows potential advantages for its use as a treatment, particularly compared the oral route. Areas covered: The authors highlight the current state of the literature and review multiple therapies for migraine-utilizing inhalation as the route of administration. The following therapeutics are discussed: inhaled ergotamine, inhaled dihydroergotamine mesylate (MAP0004), inhaled prochlorperazine, and inhaled loxapine. Coverage is also given to normobaric oxygen, hyperbaric oxygen, and nitrous oxide therapies. Expert opinion: Inhalation of MAP0004 showed promising results in terms of efficacy for acute migraine treatment in phase 3 studies, together with a more favorable tolerability profile compared to parenteral dosing and a better pharmacokinetic profile versus oral or intranasal delivery. In phase 2 trials, inhaled prochlorperazine shows good pharmacokinetics and efficacy, in contrast to inhaled loxapine that did not provide encouraging results in terms of efficacy. The authors see the potential for the use of dihydroergotamine mesylate in clinical practice pending regulatory approval.

Examining the safety, efficacy, and patient acceptability of inhaled loxapine for the acute treatment of agitation associated with schizophrenia or bipolar I disorder in adults

Agitation is a common and serious symptom of bipolar mania and schizophrenia, and can be defined as excessive motor and verbal activity. If left unrecognized and untreated, agitation can evolve into aggression, resulting in potential patient and staff injury. An ideal treatment for agitation would have a rapid onset, cause calmness without sedation, and be tolerable, efficacious, and non-coercive, while managing the underlying condition. A novel approach for the treatment of agitation is inhaled loxapine. Inhaled loxapine is rapidly absorbed into the systemic circulation through the alveoli, resulting in a near immediate onset of action. The efficacy of inhaled loxapine was established in an extensive clinical development program that included persons with schizophrenia and bipolar mania. Additionally, inhaled loxapine has comparable efficacy to intramuscular ziprasidone, olanzapine, haloperidol, aripiprazole, and lorazepam, with the added benefit of being non-painful and non-traumatizing. Inhaled loxapine carries a bolded black box warning for bronchospasm, and as a result, in the US, requires enrollment in a Risk Evaluation and Mitigation Strategy program, and is contraindicated in those with pulmonary disease. Additionally, the use of inhaled loxapine can be associated with dysgeusia and throat irritation. Inhaled loxapine requires some degree of patient cooperation, and therefore may not be appropriate for all agitated patients.

Inhaled loxapine for agitation in patients with personality disorder: an initial approach

Inhaled Loxapine (IL) has demonstrated efficacy in the treatment of agitation in schizophrenic and bipolar patients, although data in patients with Personality Disorder (PD) are scarce. To evaluate the effectiveness and safety of IL in the treatment of agitation in PD, data from 41 patients who presented at our unit with acute agitation and were treated with 9.1 mg of IL were collected retrospectively. The results showed that IL significantly decreased agitation within 10 minutes and its effect was greater at 20 minutes (Positive and Negative Syndrome Scale-excited component: from 22.78 ± 4.39 at baseline to 11.14 ± 4.17 at 20 minutes; p < 0.001; Agitation and Calmness Evaluation Scale: from 1.80 ± 0.49 at baseline to 4.53 ± 1.05 at 20 minutes; p < 0.01) without any severe adverse reactions registered. IL led to fast, safe and well-tolerated control of agitation in patients with PD.

PLACID study: A randomized trial comparing the efficacy and safety of inhaled loxapine versus intramuscular aripiprazole in acutely agitated patients with schizophrenia or bipolar disorder

The aim of the study was to investigate the efficacy and safety of inhaled loxapine compared with the intramuscular (IM) antipsychotic aripiprazole in acutely agitated patients with schizophrenia or bipolar I disorder. PLACID was an assessor-blind, parallel-group trial conducted in 23 centres in the Czech Republic, Germany, Spain, and Russia. Patients (aged 18-65 years) diagnosed with schizophrenia or bipolar I disorder experiencing acute agitation (Clinical Global Impression [CGI]-Severity score ≥ 4) while hospitalized or attending an emergency room were randomized to receive up to two doses of inhaled loxapine 9.1 mg or IM aripiprazole 9.75 mg (≥ 2 h between doses) during the 24-h study period. The primary efficacy endpoint was time to response (CGI-Improvement score 1 [very much improved] or 2 [much improved]). The primary analysis included randomized patients who provided informed consent (full analysis set [FAS]); the safety analysis included all patients who received study medication. The FAS comprised 357 patients (enrolled December 2, 2014 - October 31, 2016). The between-treatment difference in median time to CGI-Improvement response was 10 min (95% CI 0.0-30.0); p = 0.0005) in favour of inhaled loxapine (median [95% CI]: 50 min [30.0-50.0] vs 60 min [50.0-90.0] with IM aripiprazole); the difference was significant at 10 min (responders: 14% [loxapine] vs 4% [aripiprazole]; p = 0.001). There were no safety issues. Inhaled loxapine reduced agitation faster than IM aripiprazole, supporting its use as a first-line option for managing acute agitation in patients with schizophrenia or bipolar disorder.

Response to inhaled loxapine in patients with schizophrenia or bipolar I disorder: PANSS-EC responder analyses

BACKGROUND

Efficacy of inhaled loxapine 5 or 10 mg in treating agitation was shown using the Positive and Negative Syndrome Scale - Excited Component (PANSS-EC) in two Phase III randomised, double-blind, placebo-controlled trials in 344 agitated patients with schizophrenia and 314 patients with bipolar I disorder (Clinicaltrials.gov: NCT00628589, NCT00721955).

AIMS

To examine the five individual items comprising the PANSS-EC and the percentage of patients achieving a clinical response (reduction of ≥40%) in PANSS-EC (Response-40) for these two studies.

METHOD

Response-40 was examined at the primary end-point (2 h) and over time.

RESULTS

Response-40 and each PANSS-EC item score were statistically significant v. placebo at 2 h and at each assessment time point for both doses.

CONCLUSIONS

Inhaled loxapine produced rapid improvement in agitated patients with schizophrenia or bipolar I disorder, achieving Response-40 at the first assessment (10 min post dose). These results highlight the effectiveness of loxapine across all components of agitation as measured by the PANSS-EC.

DECLARATION OF INTEREST

S.Z. is a member of the speakers bureau for Grupo Ferrer. L.Z. has been a speaker and grant recipient for Teva Pharmaceuticals. J.V.C. and D.A.S. were employees of Alexza Pharmaceuticals during execution of the studies, and are currently paid consultants for and have received stock and/or stock options from Alexza Pharmaceuticals. P.P.Y. is a full-time employee and receives stock options from Teva Pharmaceuticals.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Clinical Trial Simulations and Pharmacometric Analysis in Pediatrics: Application to Inhaled Loxapine in Children and Adolescents

BACKGROUND AND OBJECTIVES

Loxapine for inhalation is a drug-device combination product approved in adults for the acute treatment of agitation associated with schizophrenia or bipolar I disorder. The primary objective of this study was to develop a clinical trial protocol to support a phase I pharmacokinetic study in children aged 10 years and older. In addition, this report details the results of the clinical study in relation to the predicted likelihood of achieving the target exposure associated with therapeutic effect in adults.

METHODS

A nonlinear mixed-effects population pharmacokinetic model was developed using adult data and was adjusted for the targeted pediatric age groups by applying allometric scaling to account for body size effects. Based on this pediatric model, age-appropriate regimens to achieve loxapine exposures similar to the ones associated with therapeutic effect in the adult studies were identified via trial simulation. D-optimal design and power analysis were conducted to identify optimal pharmacokinetic sampling times and sample size, respectively.

RESULTS

The developed clinical trial design formed the basis of a phase I study to assess the safety and pharmacokinetics of loxapine for inhalation in children aged 10 years and older (ClinicalTrials.gov ID: NCT02184767).

CONCLUSION

The results of the study indicated that overall loxapine exposures were consistent with what had been predicted by the trial simulations. The presented approach illustrates how modeling and simulation can assist in the design of informative clinical trials to identify safe and effective doses and dose ranges in children and adolescents.

Pharmacokinetics and Safety of Single-Dose Inhaled Loxapine in Children and Adolescents

This multisite open-label study sought to characterize the pharmacokinetics and safety of a single dose of inhaled loxapine in children and adolescents. Loxapine powder for oral inhalation was administered via a single-use handheld drug device to children and adolescents (aged 10-17 years) with any condition warranting chronic antipsychotic use. Patients were dosed according to body weight and cohort (<50 kg [n = 15], 2.5 or 5 mg; ≥50 kg [n = 15], 5 or 10 mg); the first 6 patients (cohort 1) enrolled in each weight group received the lower dose. Patients were enrolled in the higher-dose group (cohort 2) after an interim pharmacokinetic and safety analysis of data from cohort 1. Blood samples were collected for 48 hours after dosing to determine the pharmacokinetic profile of loxapine and its metabolites. Safety was assessed using adverse event (AE), laboratory value, physical/neurologic examination, vital sign, electrocardiogram, suicidality, and extrapyramidal symptom assessment. Thirty patients were enrolled and evaluable for pharmacokinetics. Loxapine plasma concentrations peaked by 2 to 5 minutes in most patients; systemic exposure increased with dose in both weight subgroups. Loxapine terminal elimination half-life was ∼13 to 17 hours. The most common AEs were sedation and dysgeusia. Sedation was severe in 1 patient in the <50-kg group (2.5-mg dose) and 1 patient in the ≥50-kg group (5-mg dose). No AEs indicative of bronchospasm or other serious AEs were reported. Inhaled loxapine was rapidly absorbed and generally well tolerated in pediatric patients; no new safety signals were observed.

Rationale and design of the PLACID study: a randomised trial comparing the efficacy and safety of inhaled loxapine versus IM aripiprazole in acutely agitated patients with schizophrenia or bipolar disorder

BACKGROUND

The management of acute agitation manifesting in patients with schizophrenia or bipolar disorder requires swift pharmacological intervention to provide rapid symptomatic relief and prevent escalation to aggression and violence. Antipsychotic medications are widely used in this setting and the availability of an inhaled formulation with deep lung absorption of the antipsychotic loxapine has the potential to deliver a faster onset of therapeutic effect than the available intramuscular formulations of antipsychotics.

METHODS

The efficacy of inhaled loxapine and the alternative antipsychotic aripiprazole delivered via intramuscular (IM) injection will be compared in the Phase IIIb PLACID study. Adults (18-65 years) with a confirmed diagnosis of schizophrenia or bipolar I disorder presenting with acute agitation will be randomly assigned to open-label treatment in a 1:1 ratio. Clinical evaluation will be conducted by raters blinded to treatment assignment. The primary efficacy endpoint is time to response (defined as a Clinical Global Impression of Improvement [CGI-I] score of 1 [very much improved] or 2 [much improved]). Secondary endpoints will include the percentage of responders at different time points after dosing; the proportion of patients who receive 1 or 2 doses of study drug; time to second dose; time to rescue medication; satisfaction with study drug (evaluated using Item 14 of the Treatment Satisfaction Questionnaire for Medication); and safety and tolerability. Approximately 360 patients will be recruited with an interim analysis conducted once 180 patients have completed the study to decide whether to stop for futility or continue with or without an increase in the sample size up to additional 288 patients.

DISCUSSION

The PLACID trial will assess the efficacy and safety of inhaled loxapine with deep lung absorption compared with the IM antipsychotic, aripiprazole, in acutely agitated patients with schizophrenia or bipolar disorder. In the event that the median time to response of inhaled loxapine is significantly shorter than that of the intramuscular aripiprazole, the PLACID study has the potential to support the inhaled antipsychotic therapy as the standard of care in this setting.

TRIAL REGISTRATION

The study protocol was registered with the European Clinical Trials Database on the 31 October 2014 (EudraCT number 2014-000456-29 ).

The Role of Inhaled Loxapine in the Treatment of Acute Agitation in Patients with Psychiatric Disorders: A Clinical Review

Loxapine is a first generation antipsychotic, belonging to the dibenzoxazepine class. Recently, loxapine has been reformulated at a lower dose, producing an inhaled powder that can be directly administered to the lungs to treat the agitation associated with psychiatric disorders, such as schizophrenia and bipolar disorder. Thus, the aim of this narrative and clinical mini-review was to evaluate the efficacy and tolerability of inhaled loxapine in the treatment of acute agitation in patients with psychiatric disorders. The efficacy of inhaled loxapine has been evaluated in one Phase II trial on patients with schizophrenia, and in two Phase III trials in patients with schizophrenia and bipolar disorder. Moreover, there are two published case series on patients with borderline personality disorder and dual diagnosis patients. Inhaled loxapine has proven to be effective and generally well tolerated when administered to agitated patients with schizophrenia and bipolar disorder. Two case series have suggested that inhaled loxapine may also be useful to treat agitation in patients with borderline personality disorder and with dual diagnosis, but further studies are needed to clarify this point. However, the administration of inhaled loxapine requires at least some kind of patient collaboration, and is not recommended in the treatment of severe agitation in totally uncooperative patients. Moreover, the drug-related risk of bronchospasm must always be kept in mind when planning to use inhaled loxapine, leading to a careful patient assessment prior to, and after, administration. Also, the higher costs of inhaled loxapine, when compared to oral and intramuscular medications, should be taken into account when selecting it for the treatment of agitation.

Inhaled loxapine for the urgent treatment of acute agitation associated with schizophrenia or bipolar disorder

BACKGROUND

Acute agitation is a serious complication of schizophrenia and bipolar disorder, which may escalate quickly to aggressive behavior. Rapid treatment is therefore important to calm and stabilize the patient, reducing the potential for harm to the patient and others, and allowing further assessment. Current guidelines suggest that where pharmacologic intervention is indicated, medication should preferably be non-invasive, should have a rapid onset and should control aggressive behavior in the short term without compromising the physician-patient relationship in the long term.

OBJECTIVES

This article presents an overview of a new inhaled formulation of the established antipsychotic loxapine, which aims to provide a more rapidly acting agent for the treatment of acute agitation without the disadvantages of intramuscular or intravenous injection.

DISCUSSION

Inhaled loxapine is rapidly absorbed with intravenous-like pharmacokinetics, with a time to maximum plasma concentration of 2 minutes and a plasma half-life of approximately 6 hours. In phase III studies, loxapine reduced agitation within 10 minutes of inhalation; agitation was decreased at all subsequent assessments during a 24-hour evaluation period. Inhaled loxapine was generally well tolerated with no undue sedation. The most common adverse events were dysgeusia, mild sedation, and dizziness. Inhaled loxapine is contraindicated in patients with asthma, COPD or other pulmonary disease associated with bronchospasm.

CONCLUSIONS

Inhaled loxapine rapidly reduces acute agitation in patients with schizophrenia or bipolar disorder and is generally well tolerated. The non-invasive route of delivery respects the patient's autonomy, reducing the perception of coercion or forced medication. Inhaled loxapine is therefore an effective and appropriate option for use in the emergency setting in patients with acute agitation.

Inhaled loxapine and intramuscular lorazepam in healthy volunteers: a randomized placebo-controlled drug-drug interaction study

Pharmacodynamic effects and safety of single‐dose inhaled loxapine administered via the Staccato^® system and intramuscular (IM) lorazepam in combination versus each agent alone were compared in a randomized, double‐blind, crossover study in healthy volunteers. Subjects received: inhaled loxapine 10 mg + IM lorazepam 1 mg; inhaled loxapine 10 mg + IM placebo; IM lorazepam 1 mg + Staccato placebo in random order, each separated by a 3‐day washout. Primary endpoints were maximum effect (minimum value) and area under the curve (AUC) from baseline to 2 h post treatment for respirations/min and pulse oximetry. Least‐squares means (90% confidence interval [CI]) for concomitant treatment versus each agent alone were derived and equivalence (no difference) confirmed if the 90% CI was within 0.8–1.25. Blood pressure (BP), heart rate (HR), sedation (100‐mm visual analog scale), and adverse events (AEs) were recorded. All 18 subjects (mean age, 20.4 years; 61% male) completed the study. There was no difference between inhaled loxapine + IM lorazepam and either agent alone on respiration or pulse oximetery during the 12‐h postdose period, confirmed by 90% CIs for AUC and C_min ratios. BP and HR were no different for inhaled loxapine + IM lorazepam and each agent alone over a 12‐h postdose period. Although the central nervous system sedative effects were observed for each treatment in healthy volunteers, the effect was greater following concomitant lorazepam 1 mg IM + inhaled loxapine 10 mg administration. There were no deaths, serious AEs, premature discontinuations due to AEs, or treatment‐related AEs.

A randomized, placebo-controlled repeat-dose thorough QT study of inhaled loxapine in healthy volunteers

OBJECTIVE

This randomized, double-blind, active- and placebo-controlled, crossover, thorough QT study assessed the effect of two inhaled loxapine doses on cardiac repolarization as measured by corrected QT (QTc) interval in healthy subjects (ClinicalTrials.gov NCT01854710).

METHODS

Subjects received two doses of inhaled loxapine (10 mg) 2 hours apart + oral placebo, two doses of inhaled placebo + oral placebo, or two doses of inhaled placebo + oral moxifloxacin (400 mg; positive control), with ≥ 3 days washout between treatments. Two-sided 90% confidence intervals (CIs) were calculated around least-squares mean predose placebo-subtracted individually corrected QT durations (ΔΔQTcIs) at 12 time points throughout 24 hours after dosing. A ΔΔQTcI 95% upper CI exceeding 10 msec was the threshold indicating QTc prolongation (primary endpoint). Secondary endpoints included Fridericia- and Bazettcorrected QT duration and QTcI outliers Pharmacokinetics and adverse events (AEs) were also assessed.

RESULTS

Of 60 subjects enrolled (mean age, 33.8 years; 52% male), 44 completed the study. Post loxapine dosing, no ΔΔQTcI 95% upper CI exceeded 10 msec; the largest was 6.31 msec 5 minutes post dose 2. Methodology was validated by ΔΔQTcI 95% lower CIs exceeding 5 msec at 9 of 12 time points after moxifloxacin dosing. Loxapine plasma concentrations increased rapidly (mean Cmax, 177 ng/mL; median tmax 2 minutes after dose 2, 2.03 hours after dose 1). There were no deaths, serious AEs, or AEs leading to discontinuation, and one severe AE.

CONCLUSIONS

Primary and secondary endpoints indicated two therapeutic doses of inhaled loxapine did not cause threshold QTc prolongation in this study.

Safety and tolerability of inhaled loxapine in subjects with asthma and chronic obstructive pulmonary disease--two randomized controlled trials

BACKGROUND

Loxapine, a first-generation antipsychotic, delivered with a novel inhalation delivery device developed for the acute treatment of agitation in patients with schizophrenia or bipolar disorder was evaluated in subjects with asthma or chronic obstructive pulmonary disease (COPD).

METHODS

Separate randomized, double-blind, parallel-arm, placebo-controlled trials compared two administrations of inhaled loxapine (10 mg) 10 hr apart with placebo in 52 subjects with asthma and in 53 subjects with COPD. A thermally-generated drug aerosol of loxapine was delivered to the deep lung for rapid systemic absorption. Controller medications were continued throughout the study, but quick-relief bronchodilators were withheld from 6-8 hr before through 34 hr after dose 1, unless indicated as rescue.

RESULTS

All airway adverse events (AEs) were of mild or moderate severity. Symptomatic bronchospasm occurred in 53.8% of subjects with asthma after inhaled loxapine and 11.5% after placebo; and in 19.2% of COPD subjects after inhaled loxapine and 11.1% after placebo. Subjects required inhaled albuterol as follows: asthma: 53.8% after inhaled loxapine and 11.5% after placebo; and COPD: 23.1% after inhaled loxapine and 14.8% after placebo. Respiratory signs/symptoms requiring treatment responded to rescue bronchodilator [forced expiratory volume in 1 sec (FEV(1)) return to within 10% of baseline] within 1 hr in 11 of 15 events in asthma subjects and four of seven events in COPD subjects, the remainder by the last spirometry.

CONCLUSIONS

In subjects with either asthma or COPD, FEV(1) decline and bronchospasm can occur following inhaled loxapine, but more frequently in asthmatic subjects. Most subjects with bronchospasm responded to rescue bronchodilator within 1 hr. No treatment-related serious AE occurred. Although inhaled loxapine is contraindicated in patients with active airways disease per the current approved US labeling, these studies demonstrated that rescue bronchodilator mitigated the symptomatic bronchospasms that may occur in case of inadvertent use.

Effect of smoking on the pharmacokinetics of inhaled loxapine

Background:

Loxapine inhalation powder delivered by a hand-held device as a thermally generated aerosol (ADASUVE) was recently approved in the United States and European Union for use in the acute treatment of agitation in patients with bipolar disorder or schizophrenia. As smokers comprise a large subpopulation of these patients, and many antipsychotic drugs require dose adjustments for smokers, the objective of this study was to compare the pharmacokinetics of inhaled loxapine administered to smokers and nonsmokers.

Methods:

Pharmacokinetics and sedation pharmacodynamics using a visual analog scale were studied in 35 male and female adult subjects (18 nonsmokers and 17 smokers) following a single dose of 10 mg of inhaled loxapine. Blood samples were drawn at predose, 30 seconds, 1, 2, 3, 10, 30, and 60 minutes, and 2, 6, 12, and 24 hours after dosing. Loxapine and 8-OH-loxapine were analyzed using reverse-phase liquid chromatography coupled with a tandem mass spectrometer. Pharmacokinetic parameters assessed included C_max, T_max, AUC_inf, and T_1/2 for loxapine and 8-OH-loxapine. Geometric mean ratios (GMRs) were determined for smokers to nonsmokers.

Results:

Loxapine C_max was similar in smokers and nonsmokers with a GMR of 99.0%. The median loxapine T_max was 1.88 and 1.01 minutes for nonsmokers and smokers, respectively. Loxapine AUC_inf and AUC_last values in nonsmokers were comparable with smokers (GMRs of 85.3% and 86.7%, respectively). A slight decrease in the observed mean terminal half-life values was observed for smokers (6.52 hours for smokers and 7.30 hours for nonsmokers).

Conclusions:

Sedation profiles and visual analog scale scores at each time point were similar for nonsmokers and smokers. It was concluded that inhaled loxapine does not require dosage adjustment based on smoking behavior.

Multiple dose pharmacokinetics of inhaled loxapine in subjects on chronic, stable antipsychotic regimens

This randomized, double‐blind, placebo‐controlled, parallel‐group study was to determine the pharmacokinetic characteristics, safety, and tolerability of multiple doses of inhaled loxapine aerosol in subjects on a stable, oral, chronic antipsychotic regimen. Loxapine was delivered by means of a unique thermally generated aerosol comprising drug particles of a size designed for deep lung delivery and absorption. Thirty‐two subjects were randomized 1:1:1:1 to receive inhaled loxapine (total doses of 15, 20, or 30 mg) or inhaled placebo administered in 3 divided doses, given 4 hours apart. Following inhalation, the median T_max was 2 minutes, and concentrations declined to about half C_max approximately 5 minutes later across the 3 dose levels. The dose proportionality across data from this study combined with data from the single‐dose study showed a slope (90%CI) of log AUC_inf versus log dose of 0.818 (0.762–0.875) across the 8 doses (n = 60 subjects) studied, indicating reasonable dose proportionality. The most common adverse events were cough (3 of 32, 9%), sedation (3 of 32, 9%), and dysgeusia (2 of 32, 6%). The inhalation of multiple doses of inhaled loxapine were well tolerated in study subjects and provided a safe, well‐tolerated means for rapidly and reliably achieving therapeutic plasma concentrations of loxapine. ClinicalTrials.gov identifier: NCT00555412

Inhaled vs. oral alprazolam: subjective, behavioral and cognitive effects, and modestly increased abuse potential

RATIONALE

Infrahuman and human studies suggest that a determinant of the abuse potential of a drug is rate of onset of subjective effects.

OBJECTIVES

This study sought to determine if the rate of onset of subjective effects and abuse potential of alprazolam would be increased when administered via inhalation vs. the oral route.

METHODS

Placebo, inhaled alprazolam (0.5, 1, and 2 mg), and oral alprazolam (1, 2, and 4 mg) were administered under double-blind, double-dummy conditions using a crossover design in 14 healthy participants with histories of drug abuse. Participant and observer ratings and behavioral and cognitive performance measures were assessed repeatedly during 9-h sessions.

RESULTS

Both routes of administration produced orderly dose and time-related effects, with higher doses producing greater and longer-lasting effects. Onset of subjective effects following inhaled alprazolam was very rapid (e.g., 2 vs. 49 min after 2 mg inhaled vs. oral). On measures of abuse potential (e.g., liking and good effects), inhaled alprazolam was more potent, as evidenced by a leftward shift in the dose-response curve. Despite the potency difference, at the highest doses, peak ratings of subjective effects related to abuse potential (e.g., "drug liking") were similar across the two routes. On other measures (e.g., sedation and performance), the routes were equipotent.

CONCLUSIONS

The inhaled route of administration modestly increased the abuse potential of alprazolam despite significantly increasing its rate of onset. If marketed, the reduced availability and increased cost of inhaled alprazolam may render the societal risk of increased abuse to be low.

Safety and efficacy review of inhaled loxapine for treatment of agitation

Agitation is common in patients with acute schizophrenia and bipolar disorder, and rapid and effective treatment of acute agitation is an important clinical goal. Loxapine is a first-generation antipsychotic medication available in the United States in oral form for more than three decades. In December 2012, an inhaled version of vaporized loxapine was approved by the U.S. FDA for the treatment of agitated adults in the context of schizophrenia or bipolar disorder. In this review, we examine available literature to describe efficacy and safety of inhaled loxapine in healthy patients and in those with pulmonary compromise. Limitations of the current evidence base to predict efficacy in "real world" patients are described, and safeguards necessary for appropriate use in psychiatric acute care settings are discussed.

[Inhalative loxapine: old tried and trusted medication with new indications]

Inhalative loxapine which will come onto the market shortly, is an important new alternative medication for the treatment of agitation, restlessness and tension in patients with schizophrenia and bipolar disorders. The possibility of inhaled administration provides an advantage for patients and staff in certain acute situations. In patients with obstructive lung diseases there is a danger concerning bronchospasms. The resulting safety regulations limit the easy and broad usage of inhaled loxapine slightly but these can be easily realized within hospitals. In view of the rapid onset antiagitation effect and the easy handling of inhaled loxapine, this might be a rather minor problem.

Loxapine delivered as a thermally generated aerosol does not prolong QTc in a thorough QT/QTc study in healthy subjects

The objective of this study was to establish effects of inhaled loxapine on the QTc interval in this randomized, placebo-controlled, double-blind crossover study. Forty-eight healthy volunteers received a single inhaled placebo or 10 mg loxapine. Plasma concentrations of loxapine increased with a median Tmax of 1 minute and a mean Cmax of 312 ng/mL. After an initial rapid distribution phase, plasma concentrations of loxapine declined with a terminal half-life of 8 hours. Exposure to the active metabolite 7-OH-loxapine was 15% of the parent compound based on mean AUCinf and its terminal half-life was 12 hours. Inhaled loxapine did not increase QT intervals, as demonstrated by the upper bound of the 1-sided 95% CIs placed on the point estimate of the placebo-subtracted change of QTcI (ΔΔQTcI) being less than 10 milliseconds at all 11 post-dose times. The maximum ΔΔQTcI occurred at 1 hour post-dose (LSmean 5.42 milliseconds, upper confidence bound 7.75 milliseconds). The study outcome was validated by the demonstrated assay sensitivity using the positive control moxifloxacin maximum ΔΔQTcI occurred at 3 hour post-dose (LSmean 8.36 milliseconds, lower confidence bound 5.82 milliseconds). The analyses of QTc outliers, and the lack of emergent diagnostic findings for QTcI, QTcB, and QTcF; and simple mean placebo-subtracted changes of QTcI and QTcF supported the primary QT analysis conclusion that this is a negative finding and there is no apparent QT prolongation associated with the therapeutic dose of inhaled loxapine.

CYP450 pharmacogenetic treatment strategies for antipsychotics: a review of the evidence

Although a number of first- and second-generation antipsychotics are available, achieving optimal therapeutic response for patients with schizophrenia can be challenging. The presence of polymorphic alleles for cytochrome P (CYP) 450 may result in lack of expression, altered levels of expression, or altered function of CYP450 enzymes. CYP2D6, CYP1A2, and CYP3A4/5 are major enzymes in the metabolism of antipsychotics and polymorphisms of alleles for these proteins are associated with altered plasma levels. Consequently, standard dosing may result in drug plasma concentrations that are subtherapeutic or toxic in some patients. Patient CYP450 genotype testing can predict altered pharmacokinetics, and is currently available and relatively inexpensive. Evidence-based guidelines provide dose recommendations for some antipsychotics. To date few studies have demonstrated a significant association with genotype-guided antipsychotic use and clinical efficacy. However, many studies have been small, retrospective or cohort designs, and many have not been adequately powered. Numerous studies have shown a significant association between genotype and adverse effects, such as CYP2D6 polymorphisms and tardive dyskinesia. This review summarizes evidence for the role of CYP450 genetic variants in the response to antipsychotic medications and the clinical implications of pharmacogenetics in the management of patients with schizophrenia.

Loxapine inhalation powder: a review of its use in the acute treatment of agitation in patients with bipolar disorder or schizophrenia

Loxapine is a well-established, first-generation antipsychotic agent. Loxapine inhalation powder (Adasuve(®)) was recently approved in the USA and the EU for use in the acute treatment of agitation in patients with bipolar disorder or schizophrenia. Inhaled loxapine is delivered by a hand-held, single-dose, single-use device that uses the Staccato(®) drug delivery system. With Adasuve(®), maximum plasma loxapine concentrations are reached in a median of 2 min. In two randomized, double-blind, placebo-controlled, multicentre trials, inhaled loxapine 5 or 10 mg significantly reduced agitation (assessed using Positive and Negative Syndrome Scale-Excited Component scores) in patients with bipolar I disorder or schizophrenia, with the onset of effect seen within 10 min of administration. Inhaled loxapine was generally well tolerated in phase III trials (which excluded patients with clinically significant acute or chronic pulmonary disease), with the most commonly occurring adverse events including dysgeusia and sedation. Inhaled loxapine is contraindicated in patients with airways disease associated with bronchospasm or acute respiratory signs or symptoms. In conclusion, inhaled loxapine provides a novel new option for use in the acute treatment of agitation in patients with bipolar disorder or schizophrenia, combining a rapid onset of effect with a noninvasive route of administration.

Addressing the need for rapid treatment of agitation in schizophrenia and bipolar disorder: focus on inhaled loxapine as an alternative to injectable agents

Agitation (excessive motor or verbal activity) can be associated with schizophrenia or bipolar mania, and can further escalate into aggressive behavior and potentially lead to injuries in patients and staff. Medications used to treat agitation include antipsychotics and benzodiazepines, usually administered intramuscularly when rapid action is desired. Loxapine, a first-generation antipsychotic, has recently been reformulated into an inhaled powder that allows for direct administration to the lungs, resulting in rapid absorption into the systemic circulation. Administered via a single-use device, inhaled loxapine was tested in randomized controlled trials in agitation associated with schizophrenia or bipolar mania; doses of 5 mg and 10 mg were found to be efficacious, with an apparent dose response. In the Phase III studies, number needed to treat versus placebo for a ≥40% reduction from baseline on the Positive and Negative Syndrome Scale – Excited Component (PANSS-EC) at 2 hours was three for patients with bipolar disorder, and five for 5 mg and four for 10 mg for patients with schizophrenia, with effect sizes comparable to what has been observed in analogous studies of intramuscular injection of antipsychotics or lorazepam. Separation from placebo on the PANSS-EC was as early as 10 minutes postinhalation, the first time point where this was measured. Dysgeusia was the most commonly encountered spontaneously reported adverse event. Adverse events related to extrapyramidal symptoms and akathisia were relatively rare. Spirometry studies identified the potential for bronchospasm particularly in persons with asthma. Because of concerns over pulmonary safety, inhaled loxapine is restricted to use in hospitals and patients need to be prescreened for the presence of pulmonary disease, as well as monitored for signs and symptoms of bronchospasm for 1 hour postdose administration, as per a Food and Drug Administration-mandated Risk Evaluation and Mitigation Strategy.

Rapid acute treatment of agitation in patients with bipolar I disorder: a multicenter, randomized, placebo-controlled clinical trial with inhaled loxapine

OBJECTIVE

The present study evaluated inhaled loxapine for the acute treatment of agitation in patients with bipolar I disorder.

METHODS

A Phase 3, randomized, double blind, placebo-controlled, parallel group inpatient study was performed at 17 psychiatric research facilities. Agitated patients (N=314) with bipolar I disorder (manic or mixed episodes) were randomized (1:1:1) to inhaled loxapine 5 mg or 10 mg, or inhaled placebo using the Staccato® system. Following baseline assessments, patients received Dose 1 and were evaluated for 24 hours. If required, up to two additional doses of study drug and/or lorazepam rescue medication were given. The primary efficacy endpoint was change from baseline in the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score two hours after Dose 1. The key secondary endpoint was the Clinical Global Impression-Improvement score at two hours after Dose 1. Additional endpoints included the changes from baseline in the PANSS-EC from 10 min through 24 hours after Dose 1. Safety was assessed by adverse events, vital signs, physical examinations, and laboratory tests.

RESULTS

For the primary and key secondary endpoints, both doses of inhaled loxapine significantly reduced agitation compared with placebo. Reduced agitation, as reflected in PANSS-EC score, was evident 10 min after Dose 1 with both doses. Inhaled loxapine was well tolerated, and the most common adverse events were known effects of loxapine or minor oral effects common with inhaled medications (dysgeusia was reported in 17% of patients receiving active drug versus 6% receiving placebo).

CONCLUSIONS

Inhaled loxapine provided a rapid, non-injection, well-tolerated acute treatment for agitation in patients with bipolar I disorder.

The antipsychotic drug loxapine is an opener of the sodium-activated potassium channel slack (Slo2.2)

Sodium-activated potassium (K(Na)) channels have been suggested to set the resting potential, to modulate slow after-hyperpolarizations, and to control bursting behavior or spike frequency adaptation (Trends Neurosci 28:422-428, 2005). One of the genes that encodes K(Na) channels is called Slack (Kcnt1, Slo2.2). Studies found that Slack channels were highly expressed in nociceptive dorsal root ganglion neurons and modulated their firing frequency (J Neurosci 30:14165-14172, 2010). Therefore, Slack channel openers are of significant interest as putative analgesic drugs. We screened the library of pharmacologically active compounds with recombinant human Slack channels expressed in Chinese hamster ovary cells, by using rubidium efflux measurements with atomic absorption spectrometry. Riluzole at 500 μM was used as a reference agonist. The antipsychotic drug loxapine and the anthelmintic drug niclosamide were both found to activate Slack channels, which was confirmed by using manual patch-clamp analyses (EC(50) = 4.4 μM and EC(50) = 2.9 μM, respectively). Psychotropic drugs structurally related to loxapine were also evaluated in patch-clamp experiments, but none was found to be as active as loxapine. Loxapine properties were confirmed at the single-channel level with recombinant rat Slack channels. In dorsal root ganglion neurons, loxapine was found to behave as an opener of native K(Na) channels and to increase the rheobase of action potential. This study identifies new K(Na) channel pharmacological tools, which will be useful for further Slack channel investigations.

Consistency of dosing with a thermal aerosol generation system: in vitro and in vivo correlation

Dosing consistency and reproducibility are presented for a novel pharmaceutical inhaler technology based on a thermal condensation process. Two different device platforms producing thermally generated aerosols have been created and used in clinical studies with a number of different drug compounds. Because this approach does not rely on energy from the user to disperse the aerosol particles, aerosol production is reliable, reproducible and virtually user independent following actuation. Pharmacokinetic data from multiple clinical studies show rapid absorption, dose proportionality, and concentration levels and variability similar to intravenous injection. In addition, products used in clinical trials show excellent subject consistency with the vast majority of devices delivering greater than 90% of the loaded dose and little drug exhaled.

Pulmonary delivery of therapeutic compounds for treating CNS disorders

Delivering therapeutic compounds via the lungs presents potential advantages relative to other routes of administration. Depending on the compound and the disease state, these advantages may include: non-invasive medication delivery, ease of administration, higher bioavailability leading to dose sparing and lower systemic toxicity, potentially greater blood–brain barrier penetration and rapid pharmacodynamic effect. The practice of inhaling drugs has been around for centuries, including both medical and recreational usage. It is only more recently that formal clinical development programs have been undertaken specifically to use medication delivery via the lung to achieve systemic blood levels for the treatment of CNS disorders. At present, there are several CNS therapies being developed for pulmonary administration, with some of those programs at or near the marketing authorization stage. While there are still regulatory hurdles before these therapies can be put into practice, the success of these programs thus far demonstrates the scientific viability of inhalation therapies for treating CNS disorders.

Aerosolised antipsychotic assuages agitation: inhaled loxapine for agitation associated with schizophrenia or bipolar disorder

OBJECTIVE

To describe the efficacy and safety of inhaled loxapine, a new formulation of an older antipsychotic being developed for the treatment of agitation associated with schizophrenia or bipolar disorder.

DATA SOURCES

A literature search was conducted by querying http://www.pubmed.gov, http://www.fda.gov, http://www.accessdata.fda.gov/scripts/cder/drugsatfda and http://www.clinicaltrials.gov for the search terms 'loxapine' AND 'agitation', 'inhaled loxapine', 'staccato loxapine'. The manufacturer was asked to provide copies of posters presented at national and international meetings, and to provide any copies of papers currently in press.

STUDY SELECTION

All available reports of studies were identified.

DATA EXTRACTION

Descriptions of the principal results and calculation of number needed to treat (NNT) and number needed to harm (NNH) for relevant dichotomous outcomes were extracted from the study reports.

DATA SYNTHESIS

Inhaled loxapine is delivered using a handheld device that produces a thermally generated condensation aerosol free of excipients or propellants. Time to maximum plasma concentration is approximately 2 min. In two phase III studies (one in subjects with schizophrenia, the other in subjects with bipolar disorder) inhaled loxapine 5 and 10 mg were both superior to placebo as early as 10 min after administration, as measured using the Positive and Negative Syndrome Scale excited component. Pooling together data from three efficacy studies, NNT for response for inhaled loxapine 5 or 10 mg vs. placebo were 4 (95% CI 3-5) and 3 (95% CI 3-4), respectively, with response defined as achieving a Clinical Global Impressions - Improvement score of 1 or 2 at 2 h postdose. This effect size is in the range observed for intramuscular administration of other antipsychotics for agitation associated with schizophrenia or bipolar disorder. There were no clinically relevant signals for the emergence of extra-pyramidal side effects or akathisia. The most commonly encountered adverse event appears to be dysgeusia (distorted taste sense or bad taste), with a NNH vs. placebo of 10 (95% CI 7-22) or 12 (95% CI 8-26), for loxapine 10 or 5 mg, respectively.

CONCLUSIONS

Inhaled loxapine appears efficacious and tolerable for the treatment of agitation associated with schizophrenia or bipolar disorder. Although simple to self-administer, inhaled loxapine requires a degree of cooperation from the recipient and thus will not be a substitute for an injection during psychiatric emergencies when the patient is actively refusing medication treatment. The efficacy and safety of inhaled loxapine in elderly patients and in outpatient care settings remain to be established.

Rapid acute treatment of agitation in individuals with schizophrenia: multicentre, randomised, placebo-controlled study of inhaled loxapine

BACKGROUND

There is a need for a rapid-acting, non-injection, acute treatment for agitation.

AIMS

To evaluate inhaled loxapine for acute treatment of agitation in schizophrenia.

METHOD

This phase III, randomised, double-blind, placebo-controlled, parallel-group study (ClinicalTrials.gov number NCT00628589) enrolled 344 individuals who received one, two or three doses of inhaled loxapine (5 or 10 mg) or a placebo. Lorazepam rescue was permitted after dose two. The primary efficacy end-point was change from baseline in Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) 2 h after dose one. The key secondary end-point was Clinical Global Impression-Improvement scale (CGI-I) score 2 h after dose one.

RESULTS

Inhaled loxapine (5 and 10 mg) significantly reduced agitation compared with placebo as assessed by primary and key secondary end-points. Reduced PANSS-EC score was evident 10 min after dose one with both 5 and 10 mg doses. Inhaled loxapine was well tolerated, and the most common adverse events were known effects of loxapine or minor oral effects common with inhaled medications.

CONCLUSIONS

Inhaled loxapine provided a rapid, well-tolerated acute treatment for agitation in people with schizophrenia.

Validation of HPLC–MS/MS methods for analysis of loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide in human plasma

Background: Two ESI-LC–MS/MS methods were validated for the quantitative analysis of loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide in human K2EDTA plasma. Cation-exchange solid-phase extraction (SPE) was used to extract loxapine, amoxapine and the two hydroxylated metabolites, and organic precipitation was used to quantify loxapine N-oxide. Results: Both methods were shown to be accurate (±13%), intra-assay precision was less than 15%, and inter-assay precision was less than 10% in all instances across the entire dynamic range of the assays (0.0500–50.0 ng/ml for the SPE method and 0.100–25.0 ng/ml for the precipitation method). Conclusion: The validated methods for loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide have been used to successfully support clinical trials.