Efficacy of Brexpiprazole as Adjunctive Treatment in Major Depressive Disorder With Irritability: Post Hoc Analysis of 2 Pivotal Clinical Studies

Irritability in Mood Disorders: Neurobiological Underpinnings and Implications for Pharmacological Intervention

Feeling irritable is a common experience, both in health and disease. In the context of psychiatric illnesses, it is a transdiagnostic phenomenon that features across all ages, and often causes significant distress and impairment. In mood disorders, irritability is near ubiquitous and plays a central role in diagnosis and yet, despite its prevalence, it remains poorly understood. A neurobiological model of irritability posits that, in children and adolescents, it is consequent upon deficits in reward and threat processing, involving regions such as the amygdala and frontal cortices. In comparison, in adults with mood disorders, the few studies that have been conducted implicate the amygdala, orbitofrontal cortices, and hypothalamus; however, the patterns of activity in these areas are at variance with the findings in youth. These age-related differences seem to extend to the neurochemistry of irritability, with links between increased monoamine transmission and irritability evident in adults, but aberrant levels of, and responses to, dopamine in youth. Presently, there are no specific treatments that have significant efficacy in reducing irritability in mood disorders. However, treatments that hold some potential and warrant further exploration include agents that act on serotonergic and dopaminergic systems, especially as irritability may serve as a prognostic indicator for overall clinical responsiveness to specific medications. Therefore, for understanding and treatment of irritability to advance meaningfully, it is imperative that an accurate definition and means of measuring irritability are developed. To achieve this, it is necessary that the subjective experience of irritability, both in health and illness, is better understood. These insights will inform an accurate, comprehensive, and valid interrogation of the qualities of irritability in health and illness, and allow not only a clinical appreciation of the phenomenon, but also a deeper understanding of its important role within the development and manifestation of mood disorders.

Novel antipsychotics specificity profile: A clinically oriented review of lurasidone, brexpiprazole, cariprazine and lumateperone

Second generation antipsychotics (SGAs) are effective options in the treatment of schizophrenia and mood disorders, each with characteristic efficacy and safety features. In order to optimize the balance between efficacy and side effects, it is of upmost importance to match compound specificity against patient clinical profile. As the number of SGAs increased, this review can assist physicians in the prescription of three novel SGAs already on the market, namely lurasidone, brexpiprazole, cariprazine, and lumateperone, which is in the approval phase for schizophrenia treatment at the FDA. Besides schizophrenia, EMA and/or FDA approved lurasidone for bipolar depression, brexpiprazole as augmentation in major depressive disorder and cariprazine for the acute treatment of manic or mixed episodes associated with bipolar I disorder. These new antipsychotics were developed with the aim of improving efficacy on negative and depressive symptoms and reducing metabolic and cardiovascular side effects compared to prior SGAs, while keeping the risk of extrapyramidal symptoms low. They succeeded quite well in containing these side effects, despite weight gain during acute treatment remains a possible concern for brexpiprazole, while cariprazine and lurasidone show higher risk of akathisia compared to placebo and other SGAs such as olanzapine. The available studies support the expected benefits on negative symptoms, cognitive dysfunction and depressive symptoms, while the overall effect on acute psychotic symptoms may be similar to other SGAs such as quetiapine, aripiprazole and ziprasidone. The discussed new antipsychotics represent useful therapeutic options but their efficacy and side effect profiles should be considered to personalize prescription.

Efficacy and safety of brexpiprazole as adjunctive treatment in major depressive disorder: overview of four short-term studies

Background: There is a need for effective, safe and well-tolerated pharmacotherapies for patients with major depressive disorder (MDD) who have inadequate response to antidepressant treatments (ADTs). This analysis aimed to summarize the short-term efficacy and safety of adjunctive brexpiprazole in adults with MDD. Research design and methods: A pooled analysis of data from the 6-week, randomized, double-blind treatment phases of four studies of adjunctive brexpiprazole 1-3 mg/day versus placebo in outpatients with MDD and inadequate response to ADTs (n = 1,853). Efficacy was measured by Montgomery-Åsberg Depression Rating Scale (MADRS) scores, and safety by treatment-emergent adverse events (TEAEs). Results: ADT + brexpiprazole 2-3 mg/day showed greater improvement in MADRS Total score from baseline to Week 6 than ADT + placebo (least squares mean difference: -2.15; confidence limits: -2.82, -1.48; p < 0.0001; Cohen's d effect size: 0.33). TEAEs with incidence ≥5% with ADT + brexpiprazole 1-3 mg/day were akathisia (8.0% versus 2.6% with ADT + placebo), headache (5.8% versus 6.0%), and weight increased (5.8% versus 1.6%). Conclusions: Adjunctive brexpiprazole is an efficacious and well-tolerated treatment option for adult patients with MDD and inadequate response to ADTs. Study limitations included a lack of active comparator.

Irritability and Its Clinical Utility in Major Depressive Disorder: Prediction of Individual-Level Acute-Phase Outcomes Using Early Changes in Irritability and Depression Severity

OBJECTIVE

The authors evaluated improvement in irritability with antidepressant treatment and its prognostic utility in treatment-seeking adult outpatients with major depressive disorder.

METHODS

Mixed-model analyses were used to assess changes in irritability (as measured with the five-item irritability domain of the Concise Associated Symptom Tracking [CAST-IRR] scale) from baseline to week 4 after controlling for depression severity (as measured with the 16-item Quick Inventory of Depressive Symptomatology-Clinician Rated [QIDS-C]) in the Combining Medications to Enhance Depression Outcomes (CO-MED) trial (N=664). An interactive calculator for remission (QIDS-C score ≤5) and no meaningful benefit (<30% reduction in QIDS-C score from baseline) at week 8 was developed with logistic regression analyses in the CO-MED trial using participants with complete data (N=431) and independently replicated in the Suicide Assessment and Methodology Study (SAMS) (N=163).

RESULTS

In the CO-MED trial, irritability was significantly reduced (effect size=1.06) from baseline to week 4, and this reduction remained significant after adjusting for QIDS-C change (adjusted effect size=0.36). A one-standard-deviation greater reduction in CAST-IRR score from baseline to week 4 predicted a 1.73 times higher likelihood of remission and a 0.72 times lower likelihood of no meaningful benefit at week 8, independent of baseline QIDS-C and CAST-IRR scores and reduction in QIDS-C score from baseline to week 4. The model estimates for remission (area under the curve [AUC]=0.79) and no meaningful benefit (AUC=0.76) in the CO-MED trial were used to predict remission (AUC=0.80) and no meaningful benefit (AUC=0.84) in SAMS and to develop an interactive calculator.

CONCLUSIONS

Irritability is an important symptom domain of major depressive disorder that is not fully reflected in depressive symptom severity measures. Early reductions in irritability, when combined with changes in depressive symptom severity, provide a robust estimate of likelihood of remission or no meaningful benefit in outpatients with major depression.

Brexpiprazole: a step forward for precision medicine in resistant depression

INTRODUCTION

Resistant depression is still a common and burdensome issue and there is an urgent need for new and effective adjunctive treatments. Areas covered: In this paper, the author discusses the background, trial design, results and implications of a recent study (NCT02196506, Sirius study) which confirmed the possible benefit of brexpiprazole as adjunctive treatment in depressed subjects with inadequate benefit from first line treatments. As secondary aims, the study confirmed the effects in subjects with minimal benefit from standard treatments and in subjects with anxious distress. Despite some reported side effects such as akathisia, restlessness, and increased weight, the treatment was well tolerated. Expert opinion: The unique pharmacodynamic profile of brexpiprazole, in terms of reduced dopamine intrinsic stimulation and a range of other more anxiolytic receptor effects, suggests that brexpiprazole should be preferred in specific subpopulations, particularly where a more sedative profile is needed. Indeed, this study suggests another step in the direction of precision medicine.