Brexpiprazole

Co-administration of rifampicin (600 mg twice daily for 12 days), a potent CYP3A4 inducer, with a single 4 mg oral dose of brexpiprazole resulted in an approximate 31% and 73% decrease in brexpiprazole C_max and AUC, respectively. If brexpiprazole is used concomitantly with strong CYP3A4 inducers (e.g. rifampicin), the total daily dose requirement of brexpiprazole is increased by approximately a factor of three times the recommended daily dose. Once daily dosing while CYP3A4 inducers are administered results in high peak to trough fluctuation, hence twice daily divided dosing is preferable.

CYP3A4 inhibitors

Co-administration of ketoconazole (200 mg twice daily for 7 days), a potent inhibitor of CYP3A4, with a 2 mg single oral dose of brexpiprazole increased the AUC of brexpiprazole by 97% and no change in C_max. Based on results of interaction studies, dose adjustment of brexpiprazole to half the dose is recommended when administered concomitantly with strong CYP3A4 inhibitors (itraconazole, ketoconazole, ritonavir, and clarithromycin).

CYP2D6 inhibitors

Co-administration of a 2 mg single oral dose of brexpiprazole with quinidine (324 mg/day for 7 days), a potent inhibitor of CYP2D6, increased the AUC of brexpiprazole by 94% and no change in C_max.

Based on results of interaction studies, dose adjustment of brexpiprazole to half the dose is recommended when administered concomitantly with strong CYP2D6 inhibitors (quinidine, paroxetine, and fluoxetine).

Based on estimations from the population pharmacokinetic analysis, CYP2D6 extensive metabolisers receiving both CYP3A4 and CYP2D6 inhibitors or CYP2D6 poor metabolisers receiving strong CYP3A4 inhibitors are expected to have approximately 4-fold to 5-fold increase in brexpiprazole concentrations and dose adjustment to a quarter of the dose is recommended for these subjects.

Dose adjustments should be made in patients taking concomitant strong CYP3A4 inhibitors/inducers or strong CYP2D6 inhibitors. If the CYP3A4 inhibitor/inducers or CYP2D6 inhibitor is withdrawn, the dose may need to be returned to the original dose. In case of adverse reactions despite dose adjustments of brexpiprazole, the necessity of concomitant use of brexpiprazole and CYP2D6 or CYP3A4 inhibitor should be reassessed.

Dose adjustments of brexpiprazole in patients who are CYP2D6 poor metabolisers and for concomitant use with CYP inhibitors:

Given the primary Central Nervous System (CNS) effects of brexpiprazole, caution should be used when brexpiprazole is taken in combination with alcohol or other CNS medicinal products with overlapping adverse reactions such as sedation.

If brexpiprazole is used concomitantly with strong CYP3A4 inducers (e.g. rifampicin), in a patient stabilised on brexpiprazole it is necessary to titrate the daily dose of brexpiprazole stepwise up to double the recommended dose over the course of 1 to 2 weeks. Thereafter, if according to clinical response, further dose adjustments are required, the dose may be increased up to a maximum of three times the recommended daily dose. Daily dose must not exceed 12 mg when brexpiprazole is used concomitantly with strong CYP3A4 inducers. Twice daily divided dosing of brexpiprazole is preferable as once daily dosing results in high peak to trough fluctuation.

CYP3A4 inducers exert their effect in a time-dependent manner, and may take at least 2 weeks to reach maximal effect after introduction. Conversely, on discontinuation, CYP3A4 induction may take at least 2 weeks to decline.

The maximum recommended dose in patients with moderate to severe impaired renal function is reduced to 3 mg once daily.

The maximum recommended dose in patients with moderate to severe hepatic impairment (Child-Pugh score ≥7) is reduced to 3 mg once daily.

The effect of brexpiprazole on human fertility has not been evaluated. Studies in animals have shown decreased female fertility.

A syndrome of potentially irreversible, involuntary, dyskinetic movements may develop in patients treated with antipsychotics. Although the prevalence of the syndrome appears to be highest among the elderly, especially elderly women, it is impossible to rely upon prevalence estimates to predict, at the inception of antipsychotic treatment, which patients are likely to develop the syndrome. If signs and symptoms of tardive dyskinesia appear in a patient on brexpiprazole, dose reduction or discontinuation should be considered. These symptoms can temporally deteriorate or can even arise after discontinuation of treatment.

QT prolongation can develop in patients treated with antipsychotics. In clinical trials, only a few, nonserious, QT prolongations have been reported with brexpiprazole. Caution should be exercised when brexpiprazole is prescribed in patients with known cardiovascular disease, family history of QT prolongation, electrolyte imbalance or in concomitant use with other medicinal products thought to prolong the QT interval.

Brexpiprazole can elevate prolactin levels. Elevations associated with brexpiprazole treatment are generally mild and may decline during administration, however, in some infrequent cases the effect may persist during administration.

A potentially fatal symptom complex referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with antipsychotic treatment, including brexpiprazole. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmia). Additional signs may include increased creatine phosphokinase, myoglobinuria (rhabdomyolysis), and acute renal failure. If a patient develops signs and symptoms indicative of NMS, or presents with unexplained high fever without additional clinical manifestations of NMS brexpiprazole must be discontinued immediately.

Adverse reactions related to orthostatic hypotension can include dizziness, light-headedness and tachycardia. Generally, these risks are greatest at the beginning of treatment with antipsychotics and during dose escalation. Patients at increased risk of these adverse reactions (e.g. elderly) or at increased risk of developing complications from hypotension include those with dehydration, hypovolemia, treatment with antihypertensive medicinal products, history of cardiovascular disease (e.g., heart failure, myocardial infarction, ischemia, or conduction abnormalities), history of cerebrovascular disease, as well as patients who are antipsychotic-naive. In such patients, a lower starting dose and slower titration should be considered, and orthostatic vital signs should be monitored.

Disruption of the body’s ability to reduce core body temperature has been attributed to antipsychotics. Appropriate care is advised when prescribing brexpiprazole for patients who will be experiencing conditions that may contribute to an elevation in core body temperature, e.g., exercising strenuously, exposure to extreme heat, receiving concomitant medicinal products with anticholinergic activity, or being subject to dehydration.

Oesophageal dysmotility and aspiration have been associated with antipsychotic use. Brexpiprazole should be used cautiously in patients at risk for aspiration pneumonia.

Cases of venous thromboembolism (VTE) have been reported with antipsychotics. Since patients treated with antipsychotics often present with acquired risk factors for VTE, all possible risk factors for VTE should be identified before and during treatment with brexpiprazole and preventive measures undertaken.

Extrapyramidal symptoms (including acute dystonia) are known class effects for antipsychotics. Brexpiprazole should be used with caution in patients with a known history of EPS.

Brexpiprazole has not been evaluated in patients with a history of myocardial infarction/ischaemic heart disease or clinically significant cardiovascular disease since such patients were excluded from clinical trials.

Brexpiprazole should be used with caution in patients with known cardiovascular disease (history of myocardial infarction or ischaemic heart disease, heart failure, or conduction abnormalities), cerebrovascular disease, conditions which would predispose patients to hypotension (dehydration, hypovolemia, and treatment with antihypertensive medicinal products) or hypertension (including accelerated or malignant).

Brexpiprazole has not been studied in elderly patients with dementia and is not recommended to treat elderly patients with dementia due to increased risk of overall mortality.

Impulse-control disorders including gambling disorder have been reported in patients treated with brexpiprazole. Patients can experience increased urges, particularly for gambling, and the inability to control these urges while taking brexpiprazole. Other urges, reported, include: compulsive sexual behaviours, compulsive shopping, binge eating, and other impulsive and compulsive behaviours. Patients with a prior history of impulse-control disorders may be at increased risk and should be monitored carefully. Because patients may not recognise these behaviours as abnormal, it is important for prescribers to ask patients or their caregivers specifically about the development of new or increased impulse-control disorders or other compulsive behaviours while being treated with brexpiprazole.

It should be noted that impulse-control symptoms can be associated with the underlying disorder; however, in some cases, urges were reported to have stopped when the dose was reduced or the medication was discontinued. Compulsive behaviours may result in harm to the patient and others if not recognised. Consider dose reduction or stopping the medication if a patient develops such urges while taking brexpiprazole.

Hyperglycaemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics. Risk factors that may predispose patients to severe complications include obesity and family history of diabetes.

Patients treated with any antipsychotics, including brexpiprazole, should be observed for signs and symptoms of hyperglycaemia (such as polydipsia, polyuria, polyphagia and weakness). Fasting plasma glucose should be assessed before or soon after the initiation of the antipsychotic treatment. During long term treatment the plasma glucose levels should be monitored regularly for worsening of glucose control.

Leukopenia, neutropenia and agranulocytosis (including fatal cases) have been reported during treatment with antipsychotics. Possible risk factors for leukopenia/neutropenia include pre-existing low white blood cell count (WBC) and history of drug-induced leukopenia/neutropenia. Patients with a pre-existing low WBC or a history of drug-induced leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and brexpiprazole should be discontinued at the first sign of decline in WBC, in the absence of other causative factors. Patients with neutropenia should be carefully monitored for fever or other symptoms or signs of infection and treated promptly if such symptoms or signs occur. Patients with severe neutropenia (absolute neutrophil count <1,000/mm³) should discontinue brexpiprazole and have their WBC followed until recovery.

Antipsychotics including brexpiprazole have been associated with metabolic changes, including weight gain and dyslipidaemia. An increased frequency of weight gain has been observed with increased duration of brexpiprazole treatment. At the beginning of treatment the lipid profile should be assessed. Clinical monitoring of weight and lipid profile is recommended at baseline and during treatment.

As with other antipsychotics, brexpiprazole should be used with caution in patients who have a history of seizure disorder or other conditions that potentially lower the seizure threshold. Seizures have been reported during use of brexpiprazole.

There are no or limited amount of data from the use of brexpiprazole in pregnant women. Studies in animals have shown reproductive toxicity. Brexpiprazole is not recommended during pregnancy and in women of childbearing potential not using contraception.

Neonates exposed to antipsychotics, including brexpiprazole, during the third trimester of pregnancy are at risk of adverse reactions including extrapyramidal and/or withdrawal symptoms that may vary in severity and duration following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress and feeding disorder. Consequently, new-borns should be monitored carefully.

It is unknown whether brexpiprazole/metabolites are excreted in human milk. Available pharmacodynamic/toxicological data in animals have shown excretion of brexpiprazole/metabolites in milk of rats. A risk to the new-borns/infants cannot be excluded. A decision must be made whether to discontinue breast-feeding or to discontinue/abstain from brexpiprazole therapy taking into account the benefit of breast-feeding for the child and the benefit of therapy for the woman.

Fertility

The effect of brexpiprazole on human fertility has not been evaluated. Studies in animals have shown decreased female fertility.

Brexpiprazole has minor to moderate influence on the ability to drive and use machines due to potential nervous system effects, such as sedation and dizziness that are common adverse drug reactions.

Summary of the safety profile

The most frequently observed adverse drug reactions (ADRs) were akathisia (5.6%) and weight gain (3.9%).

List of adverse reactions

The incidences of the ADRs associated with brexpiprazole therapy are listed below. The list is based on adverse reactions reported in short-term placebo-controlled phase 2 and 3 clinical trials with relevant therapeutic doses (2 mg to 4 mg).

All ADRs are listed by system organ class (SOC) and frequency: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1,000), very rare (<1/10,000) and not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.

Immune system disorders

Common: Rash

Uncommon: Angioedema, Urticaria, Swelling face

Metabolism and nutrition disorders

Common: Weight increase

Psychiatric disorders

Uncommon: Suicide attempt, Suicidal ideation

Not known: Gambling disorder, Impulsive behaviour, Binge eating, Compulsive shopping, Compulsive sexual behaviour

Nervous system disorders

Common: Akathisia, Dizziness, Tremor, Sedation

Uncommon: Parkinsonism

Not known: Seizures, Neuroleptic malignant syndrome (NMS)

Cardiac disorders

Not known: Electrocardiogram, QT prolonged

Vascular disorders

Uncommon: Venous thromboembolism (including pulmonary embolism and deep vein thrombosis), Orthostatic hypotension

Respiratory, thoracic and mediastinal disorders

Uncommon: Cough

Gastrointestinal disorders

Common: Diarrhoea, Nausea, Abdominal pain upper

Uncommon: Dental caries Flatulence

Musculoskeletal and connective tissue disorders

Common: Back pain, Pain in extremity

Uncommon: Myalgia

Not known: Rhabdomyolysis

Pregnancy, puerperium and perinatal conditions

Not known: Drug withdrawal syndrome neonatal

Investigations

Very common: Blood prolactin increased¹

Common: Blood creatine phosphokinase increased

Uncommon: Blood pressure increased, Blood triglycerides increased, Hepatic enzymes increased

¹ The categorisation of blood prolactin increased is based on Potentially Clinically Relevant (PCR) criteria of >1 × upper limit of normal (ULN).

Description of selected adverse reactions

Extrapyramidal Symptoms (EPS)

Akathisia was the most frequently reported EPS related ADR in the brexpiprazole 2 mg/day to 4 mg/day group (5.6%) compared to 4.5% in placebo, followed by tremor (2.7%) compared to 1.2% in placebo. The incidences of other EPS-related ADRs reported in short-term, controlled trials are dyskinesia (0.4%), extrapyramidal disorder (1.8%) and Parkinsonism (0.4%).

Akathisia

From fixed-dose trials there appears to be a dose-response relationship for akathisia in patients treated with brexpiprazole, with an increasing frequency with higher doses. The incidence of akathisia in the brexpiprazole 1 mg/day, 2 mg/day, and 4 mg/day groups was 3.0%, 4.6%, and 6.5%, respectively, compared with 5.2% of subjects in the placebo group. The incidence of akathisia in the short-term, controlled trials (5.4%) was similar to the incidence in the long-term, open-label trials (5.7%).

Suicidality

In short-term, controlled trials, Treatment Emergent Adverse Events (TEAEs) related to suicidality were reported for 8 subjects (0.5%, 2 serious events, 1 leading to discontinuation) in the all brexpiprazole treatment group and 3 subjects (0.4%, none serious) in the placebo group. In long-term, open-label trials, TEAEs related to suicidality were reported for 23 subjects (1.6%). Overall in the brexpiprazole clinical development program for schizophrenia, one death due to suicide, considered not drug related by the investigator, occurred. Spontaneous cases reporting completed suicide and suicide attempt have been reported in the post-marketing setting.

QT prolongation

In the short-term controlled trials with brexpiprazole, 3 TEAEs related to QT prolongation were reported in the 2 mg to 4 mg group (0.3%), compared with 3 TEAEs (0.5%) reported for subjects on placebo. The incidence of TEAEs in long-term trials was similar to that of the short-term trials. The effects of brexpiprazole at therapeutic (4 mg) and supra-therapeutic (12 mg) doses on QT interval were evaluated in subjects with schizophrenia or schizoaffective disorder in a randomised, double-blind, placebo- and positive-controlled (moxifloxacin), parallel-arm trial. Subgroup analyses from this trial suggested that the QTc prolongation was larger in female subjects than in males.

Weight gain

In short-term, controlled trials, the percentage of subjects with clinically significant weight gain (increase of ≥7% from baseline in body weight) was 9.1% in the brexpiprazole 2 mg/day to 4 mg/day group, compared with 3.8% in the placebo group. In the long-term, open-label trial, the percentage of subjects with clinically significant weight gain (increase of ≥7% in body weight) at any visit was 20.7% and 0.4% of the subjects discontinued due to weight gain. In subjects who had a weight gain ≥7% from baseline, weight increased over time, with mean weight gain up to 10.2 kg at week 52. The mean change in body weight overall for the brexpiprazole group in the long term, open label trial was 2.1 kg at week 52.

Prolactin

The incidence of blood prolactin increased was 0.9% in 2 mg to 4 mg brexpiprazole group compared to that of 0.5% in placebo in short-term, controlled trials. Higher frequencies of prolactin increased (1.5% versus 0.60%) were observed in females compared to males in short-term trials. In addition, the frequencies of prolactin elevations >1 × ULN in the 2 mg to 4 mg brexpiprazole group was 13.7% in females versus 6.4% in placebo and 11.1% in males versus 10.3% in placebo group.

Neuroleptic malignant syndrome

A potentially fatal symptom complex referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with brexpiprazole.

Nausea

For nausea, the incidence in the 2 mg to 4 mg brexpiprazole group was 2.3% overall in short-term controlled trials, compared to 2.0% in placebo; for vomiting, these incidences were 1.0% in the brexpiprazole-treated group compared to 1.2% in placebo group.

In terms of gender differences, there were higher observed frequencies of nausea (4.8% versus 2.8%) and vomiting (4.6% versus 1.4%) in females compared to males among brexpiprazole-treated subjects in short-term trials, in subjects receiving placebo: the frequency for nausea was 2.8% for males versus 3.2% for females and for vomiting the frequency was 3.0% for males versus 2.6% for females.