Efficacy and safety of 24-week pramipexole augmentation in patients with treatment resistant depression. A retrospective cohort study

Comparative Short- and Long-Term Effectiveness and Safety of Pramipexole and Aripiprazole Augmentation in Treatment-Resistant Unipolar Depression: An Observational Study

BACKGROUND

This study compares the short- and long-term effectiveness and safety of pramipexole augmentation (PA) and aripiprazole augmentation (AA) for unipolar treatment-resistant depression (TRD).

METHODS

Patients were recruited in a private out-patients clinic specializing in mood disorders. At intake and at each visit, depressive and (hypo)manic symptoms, clinical status, and level of functioning were evaluated with appropriate scales. The trend of outcomes was analyzed using mixed-effect linear regression models.

RESULTS

The study includes 81 patients with unipolar TRD treated with PA and 51 with AA. After 12 and 24 weeks of treatment with PA, the predicted response (64.1% and 76.2%) and remission rates (49.7% and 72.7%) were significantly higher than the predicted response (32.2% and 38.0%) and remission rates (18.9% and 28.1%) for AA. The improvement in psychosocial functioning was significantly greater and faster in PA than in AA. PA showed significant superiority over AA as a maintenance strategy (time spent ill and psychosocial functioning) up to 12 months. No difference in safety was found at each time point.

CONCLUSIONS

PA could be an alternative option for the short- and long-term treatment of unipolar TRD, more effective than AA and similar in safety. These preliminary results need confirmation from randomized clinical trials.

Pramipexole improves depression-like behavior in diabetes mellitus with depression rats by inhibiting NLRP3 inflammasome-mediated neuroinflammation and preventing impaired neuroplasticity

BACKGROUND

Diabetes mellitus (DM) is frequently associated with the occurrence and development of depression, and the co-occurrence of diabetes mellitus with depression (DD) may further reduce patients' quality of life. Recent research indicates that dopamine receptors (DRs) play a crucial role in immune and metabolic regulation. Pramipexole (PPX), a D2/3R agonist, has demonstrated promising neuroprotective and immunomodulatory effects. Nevertheless, the therapeutic effects and mechanisms of action of PPX on DM-induced depression are not clear at present.

METHODS

Depression, DM, and DD were induced in a rat model through a combination of a high-fat diet (HFD) supplemented with streptozotocin (STZ) and chronic unpredictable mild stress (CUMS) combined with solitary cage rearing. The pathogenesis of DD and the neuroprotective effects of DRs agonists were investigated using behavioral assays, enzyme-linked immunosorbent assay (ELISA), hematoxylin-eosin (HE) staining, Nissl staining, Western blotting (WB) and immunofluorescence (IF).

RESULTS

DD rats exhibited more severe dopaminergic, neuroinflammatory, and neuroplastic impairments and more pronounced depressive behaviors than rats with depression alone or DM. Our findings suggest that DRs agonists have significant therapeutic effects on DD rats and that PPX improved neuroplasticity and decreased neuroinflammation in the hippocampus of DD rats while also promoting DG cell growth and differentiation, ultimately mitigating depression-like behaviors.

LIMITATION

Our study is based on a rat model. Further evidence is needed to determine whether the therapeutic effects of PPX apply to patients suffering from DD.

CONCLUSIONS

Neuroinflammation mediated by damage to the dopaminergic system is one of the key pathogenic mechanisms of DD. We provide evidence that PPX has a neuroprotective effect on the hippocampus in DD rats and the mechanism may involve the inhibition of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation by DRs to attenuate the neuroinflammatory response and neuroplasticity damage.

Safety and tolerance of combination of monoamine oxidase inhibitors and direct dopamine agonists in adults and older adults with highly resistant depression

INTRODUCTION

Dopamine (DA) is likely to be involved in some depressive dimensions, such as anhedonia and amotivation, which account for a part of treatment-resistant forms. Monoamine oxidase inhibitors (MAOI) and direct D2 and D3 receptors agonists (D2/3r-dAG) are known to help, but we lack safety data about their combined usage. We report on safety and tolerance of the MAOI+D2r-dAG combination in a clinical series.

METHOD

All patients referred to our recourse center for depression between 2013 and 2021 were screened to select those who did receive the combo. Data were extracted from clinical files.

RESULTS

Sixteen patients of 60±17 years of age (8 women, 7 with age>65years, all suffered from treatment resistant depression, 7 with bipolar disorder) received the combo. There were no life-threatening adverse effects (AE). However, AE were reported by 14 patients (88%) most of which were mild and consisted of insomnia, nausea, nervousness, confusion, impulse control disorder and/or "sleep attacks". One patient presented a serious AE requiring a short hospitalization for confusion. Intolerance led to failure to introduce treatment in two patients (13%). The retrospective non-interventional design, the variety of molecules, and the modest sample size limited the scope of these results.

CONCLUSION

There was no life-threatening safety issue in combining MAOI and D2/3r-dAG, especially regarding cardiovascular side effects. The systematic screening of AE might account for their frequency, but these precluded the treatment in only two patients. Comparative studies are needed to assess the efficacy of this new combination.

Treatment-Resistant Depression in Real-World Clinical Practice: A Systematic Literature Review of Data from 2012 to 2022

OBJECTIVE

Real-world evidence in treatment-resistant depression (TRD; commonly defined as non-response to ≥ 2 consecutive treatments at adequate dosage and duration) is lacking. A systematic literature review was conducted to understand disease burden and treatment outcomes for patients with TRD, studied in a real-world setting over the last decade.

DATA SOURCES

A literature search was conducted in May 2022 in MEDLINE, Embase, The Cochrane Libraries and PsycINFO, comprising studies published from 2012 to 2022. Bibliographies of all relevant identified systematic reviews and relevant conference proceedings from 2020 to 2022 were manually hand-searched.

STUDY SELECTION

Real-world studies, including cohort, cross-sectional, case-control, chart review and registry studies, published in English and reporting outcomes in adults with TRD, were included.

DATA EXTRACTION

Extracted data included study and baseline disease characteristics, treatment type, treatment response, clinical outcomes and health-related quality of life.

RESULTS

Twenty studies were included. Criteria for TRD varied, but patients typically experienced long-lasting depression (range 1.4 to 16.5 years). Across studies, mean disease severity scores demonstrated moderate to severe depression, reflecting a high burden of disease at baseline. Remission rates were typically low but generally increased with longer follow-up durations. However, the heterogeneity of interventions, follow-up durations (range 2 weeks to 9.4 years) and assessment tools precluded their quantitative synthesis. Studies were frequently limited by low sample size (range 14 to 411 patients) and health-related quality of life was infrequently assessed.

CONCLUSIONS

There is a lack of clinical consensus regarding the definition, assessment and monitoring of TRD in real-world practice. Nevertheless, TRD carries a high burden of illness and there is an unmet need for faster and more effective treatments. To better understand the personal burden of affected patients, future studies would benefit from standardisation of severity assessment and measures of treatment effectiveness, as well as greater consideration of health-related quality of life.

Pramipexole Augmentation for Treatment-Resistant Unipolar and Bipolar Depression in the Real World: A Systematic Review and Meta-Analysis

BACKGROUND

Pramipexole is a dopamine full agonist approved for the treatment of Parkinson's disease and restless legs syndrome. Its high affinity for the D3 receptor and neuroprotective, antioxidant, and anti-inflammatory activity provides a rationale for the treatment of depression. In this paper, we review studies on the effectiveness and safety of antidepressant pramipexole augmentation in treatment-resistant depression.

METHODS

This comprehensive systematic review and meta-analysis of observational studies on pramipexole-antidepressant augmentation included patients with resistant unipolar and bipolar depression. The primary outcome measure was the treatment response, measured at the study endpoint.

RESULTS

We identified 8 studies including 281 patients overall, 57% women and 39.5% with bipolar disorder and 60.5% with major depressive disorder. The mean follow-up duration was 27.3 weeks (range 8-69). The pooled estimate of treatment response was 62.5%, without significant differences between unipolar and bipolar depression. Safety was good, with nausea and somnolence the most frequent side effects.

CONCLUSIONS

The findings of this systematic review, needing further confirmation, show that off-label use of pramipexole as augmentation of antidepressant treatment could be a useful and safe strategy for unipolar and bipolar treatment-resistant depression.

[Slow-wave sleep and the possibilities of modern insomnia therapy]

Effective therapy of insomnia, especially chronic insomnia, is one of the most pressing neuropsychiatric problems. Unfortunately, at present in the Russian Federation, as in most other countries of the world, there are no officially approved drugs for long-term treatment of insomnia. In this regard, the use of medical sedation agents that do not have restrictions on the duration of use is of considerable interest. This review considers drugs of various psychopharmacological classes, one way or another used in practice for the correction of sleep disorders, especially in patients with underlying comorbid pathology.

Evidence on sociodemographic and clinical correlates of antidepressant combination or augmentation with second-generation antipsychotics in major depressive disorder

About two thirds of the patients with major depressive disorder (MDD) do not sufficiently respond to monotherapy with antidepressants (ADs) which makes them reliant on further treatment approaches. Hereby, combination of different ADs and augmentation with second-generation antipsychotics (SGAs) are widely used and recommended psychopharmacotherapeutic strategies. The present secondary analyses are based on an international, naturalistic, cross-sectional multicenter study conducted by the European Group for the Study of Resistant Depression. Comparing socio-demographic and clinical characteristics of 436 adult MDD patients receiving either SGAs (N = 191, 43.8%) or ADs (N = 245, 56.2%), that were additionally administered to their first-line AD psychopharmacotherapy, we aimed to identify possible trajectories of decision-making for clinicians regarding which treatment option to prefer in individual patients. Our most robust findings represent an association of SGA augmentation with the presence of psychotic symptoms, longer mean duration of lifetime psychiatric hospitalizations, employment of further augmentation strategies with mood-stabilizers and benzodiazepines, and a trend towards higher mean daily dosages of their first-line ADs and current suicidal risk. Treatment outcome was not significantly different between patients receiving either SGA augmentation or AD combination. Being aware of limitations inherent to the cross-sectional study design and the lack of randomization, more severe and rather chronic conditions in MDD seemed to encourage clinicians to choose SGA augmentation over AD combination. The fact that mood-stabilizers and/or benzodiazepines were more frequently co-administered with SGAs may represent a requirement of an overall refined psychopharmacotherapy including additional fast-acting agents with potent AD, tranquilizing and anti-suicidal effects in MDD patients experiencing challenging clinical manifestations. New glutamatergic substances seem to be promising in this regard.

Involvement of DA D3 Receptors in Structural Neuroplasticity of Selected Limbic Brain Circuits: Possible Role in Treatment-Resistant Depression

Structural neuroplasticity in the adult brain is a process involving quantitative changes of the number and size of neurons and of their dendritic arborization, axon branching, spines, and synapses. These changes can occur in specific neural circuits as adaptive response to environmental challenges, exposure to stressors, tissue damage or degeneration. Converging studies point to evidence of structural plasticity in circuits operated by glutamate, GABA, dopamine, and serotonin neurotransmitters, in concert with neurotrophic factors such as Brain Derived Neurotrophic Factor (BDNF) or Insulin Growth Factor 1 (IGF1) and a series of modulators that include circulating hormones. Intriguingly, most of these endogenous agents trigger the activation of the PI3K/Akt/mTOR and ERK1/2 intracellular pathways that, in turn, lead to the production of growth-related structural changes, enhancing protein synthesis, metabolic enzyme functions, mitogenesis for energy, and new lipid-bilayer membrane apposition. The dopamine (DA) D3 receptor has been shown to play a specific role by inducing structural plasticity of the DAergic neurons of the nigrostriatal and mesocorticolimbic circuit, where they are expressed in rodents and humans, via activation of the mTORC1 and ERK1/2 pathways. These effects are BDNF-dependent and require the recruitment of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors to allow the structural changes. Since in mood disorders, depression and anhedonia have been proposed to be associated with impaired neuroplasticity and reduced DAergic tone in brain circuits connecting prefrontal cortex, ventral striatum, amygdala, and ventral mesencephalon, activation of D3 receptors could provide a therapeutic benefit. Sustained improvements of mood and anhedonia were observed in subjects with an unsatisfactory response to serotonin uptake inhibitors (SSRI) when treated with D3-preferential D2/D3 agonists such as pramipexole and ropinirole. The recent evidence that downstream mTOR pathway activation in human mesencephalic DA neurons is also produced by ketamine, probably the most effective antidepressant currently used in subjects with treatment-resistant depression, further supports the rationale for a D3 receptor activation in mood disorders.