Add-on of aripiprazole improves outcome in clozapine-resistant schizophrenia

Third-generation antipsychotics in patients with schizophrenia and non-responsivity or intolerance to clozapine regimen: What is the evidence?

Clozapine is considered « the golden standard » for the management of treatment-resistant schizophrenia, but many patients do not present adequate responsivity even to this antipsychotic. If we add the need to strictly monitor the hematologic and cardiometabolic adverse events during each clozapine trial and the difficulty of preserving therapeutic adherence in patients with low insight, residual negative/positive symptoms, or economic challenges, then the necessity of exploring alternative interventions for these patients becomes obvious. Also, in case of intolerance to clozapine or where clozapine did not induce remission, clinicians have to find new ways to help their patients. Switching to other antipsychotics or using these agents as add-ons to clozapine are the main interventions explored in this review, for patients with schizophrenia resistant to clozapine (ultra-resistant schizophrenia, URS). When clozapine intolerance is detected, conversion to another antipsychotic with distinct pharmacologic properties or formulation (e.g., long-acting intramuscular injectable agents, LAI) may be a useful option. Third-generation antipsychotics (TGA) have been selected for their distinct pharmacodynamically profile, which allows, at a theoretical level, their use in combination with clozapine. This narrative review is based on searching four electronic databases, that retrieved 19 primary and secondary reports on aripiprazole (seven case reports or case series presenting 24 patients; nine clinical trials, and three systematic reviews/meta-analyses), two primary reports on brexpiprazole (case report and case series, N = 3 patients), and six primary reports on cariprazine (case reports and case series, N = 14 patients). Based on the information collected from these reports, which included oral and LAI formulations, the TGA most supported by evidence for the augmentation of clozapine is aripiprazole (high-and medium-quality data), followed by cariprazine (low-quality data). Brexpiprazole has not yet been systematically explored for this indication, and in the case of lumateperone, no report could be found. The efficacy of aripiprazole and cariprazine was supported in the domains of positive, negative, and general symptoms, and aripiprazole may positively impact the metabolic profile in patients with URS. Also, adding TGA may lead to a decrease in the dose of clozapine concomitantly administered. More data derived from good quality research are needed in order to confirm the circumstances of TGAs recommendation in patients with URS, either as monotherapy, or added to clozapine.

Clozapine and paliperidone palmitate antipsychotic combination in treatment-resistant schizophrenia and other psychotic disorders: A retrospective 6-month mirror-image study

Background:

Around 30% of patients with schizophrenia are considered treatment resistant (TRS). Only around 40% of TRS patients respond to clozapine. Long acting injectable antipsychotics could be a useful augmentation strategy for nonresponders.

Methods:

We conducted a multicenter, observational, naturalistic, retrospective, 6-month mirror-image study to evaluate the efficacy and tolerability of clozapine and paliperidone palmitate association in 50 patients with TRS and other psychotic disorders. Clinical outcomes and side effects were systematically assessed.

Results:

Six months after starting the combined treatment, participants showed a significant relief of symptoms, decreasing the Brief Psychiatric Rating Scale total score from 18.32 ± 7.71 to 7.84 ± 5.16 (p < 0.001). The number of hospitalizations, the length of hospital stays and the number of visits to emergency services also decreased, while an increase of the functionality was observed (Personal and Social Performance total score increased from 46.06 ± 118.7 to 60.86 ± 18.68, p < 0.001). There was also a significant decrease in the number and severity of side effects with the combination therapy, decreasing the Udvalg for Kliniske Undersogelser total score from 10.76 ± 8.04 to 8.82 ± 6.63 (p = 0.004).

Conclusions:

This study provides the first evidence that combining clozapine with paliperidone palmitate in patients with TRS and other psychotic disorders could be effective and safe, suggesting further research with randomized controlled trials of augmentation strategies for clozapine nonresponder patients.

Policy Significance Statement:

Patients with psychotic disorders such as schizophrenia show a variable response to antipsychotic treatments. Around 30% of patients are considered treatment resistant, indicated by insufficient symptom control to at least two different drugs. In these resistant cases, clozapine should be indicated, as it has shown to be superior to other options. However, only 40% of patients respond to clozapine, being necessary to establish which treatments could best potentiate clozapine action. Combining clozapine with long acting injectable antipsychotics, and particularly paliperidone palmitate, could be a useful strategy. We conducted a multicenter study of 50 patients with treatment-resistant schizophrenia and other psychotic disorders comparing the efficacy and tolerability in the 6 month-period prior and after starting the clozapine and paliperidone palmitate association. Our study suggests that this combination could be effective and safer, laying the groundwork for future clinical trials with this combination.

Adjunctive effects of aripiprazole on metabolic profiles: comparison of patients treated with olanzapine to patients treated with other atypical antipsychotic drugs

Metabolic abnormalities are serious adverse effects of atypical antipsychotic treatment. This study aims to determine the effects of adjunctive aripiprazole on metabolic profiles among patients receiving treatment with atypical antipsychotics, and to examine whether these effects are different from that of pre-existing atypical antipsychotics. In the 8-week open-label trial, aripiprazole was added to patients who were receiving treatment with atypical antipsychotics and had experienced weight gain or dyslipidemia. The dosage of pre-existing atypical antipsychotics was fixed, while the dosage of aripiprazole ranged from 5 to 20 mg/day during the study period. Metabolic profiles, including body weight, body mass index (BMI), plasma levels of fasting glucose, triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and adiponectin, were measured at baseline and week 8. As a result, 43 subjects (16 males and 27 females, mean age: 37.8±10.8 years) completed the study. The pre-existing antipsychotics were olanzapine (n=12), risperidone (n=19), quetiapine (n=6) and amisulpiride (n=6). The mean dosage of adjunctive aripiprazole was 9.9±3.2 mg/day. After the aripiprazole-augmented regimen for 8 weeks, patients treated with olanzapine had significant decreases in body weight, BMI and triglyceride levels, and had significant increases in adiponectin levels. For patients treated with other atypical antipsychotics, none of the metabolic parameters significantly changed after administering aripiprazole. In conclusion, aripiprazole-augmented treatment might be beneficial for the metabolic regulation of patients being treated with a stable dose of olanzapine, but not for those treated with other atypical antipsychotics. A long-term, randomized, double-blind controlled design is suggested to confirm these findings.

Augmentation of clozapine with another pharmacological agent: treatment for refractory schizophrenia in the 'real world'

OBJECTIVE

Refractory schizophrenia (SZ) affects approximately 30% of people with SZ. Clozapine (CLZ) is the gold standard treatment; however, there are still patients who are non-responsive or partially responsive to treatment. Although a lack of evidence exists in reality, these patients are treated with a combination of agents in addition to CLZ. Therefore, this article reviews the prevalence of the augmentation of CLZ with additional agents.

METHOD

This study was cross-sectional; physicians in a region of Australia in May 2011 were contacted to provide details of their patients on CLZ and any additional agents. The data set consists of 84 patients.

RESULTS

The majority of the patients 84.5% were taking at least one additional agent. Of those taking additional agents, they derived from the following classes' antipsychotics (72%), antidepressants (30%), mood stabilisers (17%), antimetabolic agents (13%), benzodiazepines (7%), anticholinergics (4%) and miscellaneous agents (12.5%).

CONCLUSION

It is apparent that CLZ is routinely augmented with other agents despite the lack of an evidence base. However, concerning was the lack of augmentation with antimetabolic agents despite the paucity of literature reporting the detrimental impact of antipsychotic treatment upon patients metabolic indices. The findings are discussed in the context of the current recommendations and empirical literature.

Role of aripiprazole in treatment-resistant schizophrenia

About one third of patients with schizophrenia respond unsatisfactorily to antipsychotic treatment and are termed "treatment-resistant". Clozapine is still the gold standard in these cases. However, 40%-70% of patients do not improve sufficiently on clozapine either. In the search for more efficacious strategies for treatment-resistant schizophrenia, drugs with different pharmacological profiles seem to raise new hopes, but are they valid? The aim of this review was to evaluate the evidence for aripiprazole as a potential strategy in monotherapy or combination therapy for patients with treatment-resistant schizophrenia. The evidence for aripiprazole monotherapy and for the combination of aripiprazole with psychotropics other than clozapine is scant, and no recommendation can be made on the basis of the currently available data. More effort has been made in describing combinations of aripiprazole and clozapine. Most of the open-label and case studies as well as case reports have shown positive effects of this combination on overall psychopathology and to some extent on negative symptoms. Several reports describe the possibility of dose reduction for clozapine in combination with aripiprazole, a strategy that might help so-called "treatment-intolerant" patients. The findings of four randomized controlled trials with respect to changes in psychopathology seem less conclusive. The most commonly found beneficial effects are better metabolic outcomes and indicators of the possibility of reducing the clozapine dose. However, other side effects, such as akathisia, are repeatedly reported. Further, none of the studies report longer-term outcomes. In the absence of alternatives, polypharmacy is a common strategy in clinical practice. Combining aripiprazole with clozapine in clozapine-resistant or clozapine-intolerant patients seems to be worthy of further investigation from the pharmacological and clinical points of view.