Combinatorial Pharmacogenomic Testing Improves Outcomes for Older Adults With Depression

Pharmacogenomic Clinical Support Tools for the Treatment of Depression

OBJECTIVE

In this review, the authors update the 2018 position statement of the American Psychiatric Association Council of Research Workgroup on Biomarkers and Novel Treatments on pharmacogenomic (PGx) tools for treatment selection in depression.

METHODS

The literature was reviewed for new clinical trials and meta-analyses, published from 2017 to 2022, of studies using PGx tools for treatment selection in depression. The blinding and control conditions, as well as primary and secondary outcomes and post hoc analyses, were summarized.

RESULTS

Eleven new clinical trials and five meta-analyses were identified; all studies had primary outcome measures related to speed or efficacy of treatment response. Three trials (27%) demonstrated efficacy on the primary outcome measure with statistical significance; the three studies used different PGx tools; one study was open-label and the other two were small single-blind trials. Five trials (45%) did not detect efficacy with statistical significance on either primary or secondary outcome measures. Only one trial (9%) used adverse events as a primary outcome measure. All studies had significant limitations; for example, none adopted a fully blinded study design, only two studies attempted to blind the treating clinician, and none incorporated measures to estimate the effectiveness of the blinds or the influence of lack of blinding on the study results.

CONCLUSIONS

The addition of these new data do not alter the recommendations of the 2018 report, or the advice of the U.S. Food and Drug Administration, that the evidence does not support the use of currently available combinatorial PGx tools for treatment selection in major depressive disorder. Priority efforts for future studies and the development and testing of effective tools include fully blinded study designs, inclusion of promising genetic variants not currently included in any commercially available tests, and investigation of other uses of pharmacogenomics, such as estimating the likelihood of rare adverse drug effects, rather than increasing the speed or magnitude of drug response.

Documentation of results and medication prescribing after combinatorial psychiatric pharmacogenetic testing: A case for discrete results

PURPOSE

Combinatorial pharmacogenetic (PGx) panels intended to aid psychiatric prescribing are available to clinicians. Here, we evaluated the documentation of PGx panel results and subsequent prescribing patterns within a tertiary health care system.

METHODS

We performed a query of psychiatry service note text in our electronic health record using 71 predefined PGx terms. Patients who underwent combinatorial PGx testing were identified, and documentation of test results was analyzed. Prescription data following testing were examined for the frequency of prescriptions influenced by genes on the panel along with the medical specialties involved.

RESULTS

A total of 341 patients received combinatorial PGx testing, and documentation of results was found to be absent or incomplete for 198 patients (58%). The predominant method of documentation was through portable document formats uploaded to the electronic health record's "Media" section. Among patients with at least 1 year of follow-up, a large majority (194/228, 85%) received orders for medications affected by the tested genes, including 132 of 228 (58%) patients receiving at least 1 non-psychiatric medication influenced by the test results.

CONCLUSION

Results from combinatorial PGx testing were poorly documented. Medications affected by these results were often prescribed after testing, highlighting the need for discrete results and clinical decision support.

Pharmacokinetic Markers of Clinical Outcomes in Severe Mental Illness: A Systematic Review

The term severe mental illness (SMI) encompasses those psychiatric disorders exerting the highest clinical burden and socio-economic impact on the affected individuals and their communities. Pharmacogenomic (PGx) approaches hold great promise in personalizing treatment selection and clinical outcomes, possibly reducing the burden of SMI. Here, we sought to review the literature in the field, focusing on PGx testing and particularly on pharmacokinetic markers. We performed a systematic review on PUBMED/Medline, Web of Science, and Scopus. The last search was performed on the 17 September 2022, and further augmented with a comprehensive pearl-growing strategy. In total, 1979 records were screened, and after duplicate removal, 587 unique records were screened by at least 2 independent reviewers. Ultimately, forty-two articles were included in the qualitative analysis, eleven randomized controlled trials and thirty-one nonrandomized studies. The observed lack of standardization in PGx tests, population selection, and tested outcomes limit the overall interpretation of the available evidence. A growing body of evidence suggests that PGx testing might be cost-effective in specific settings and may modestly improve clinical outcomes. More efforts need to be directed toward improving PGx standardization, knowledge for all stakeholders, and clinical practice guidelines for screening recommendations.

Evaluating treatment outcomes in pharmacogenomic-guided care for major depression: A rapid review and meta-analysis

Pharmacogenomic (PGx) testing may increase the probability of remission and response in patients with major depressive disorder (MDD) undergoing pharmacotherapy. Given the potential implications of these outcomes and recent proliferation of PGx studies, we conducted a systematic review to evaluate the effectiveness of PGx testing on clinical outcomes in patients with MDD as compared to treatment as usual (TAU). MEDLINE, Embase, PsycInfo, and CENTRAL were searched for English-language articles from 2000 to 2021 for randomized controlled trials (RCTs) comparing PGx-guided treatment vs. TAU in patients with MDD. Meta-analyses were conducted in R. Ten RCTs were included: eight reported remission and seven reported response. The best available evidence suggests that PGx-guided care for moderate-to-severe adult depression is more likely to result in remission and response than TAU (both risk ratios significant). However, there are limitations in the evidence base, including high risk of bias and inconsistency between trials. Despite the consequent very low certainty in the magnitude of effect, there is confidence in the direction. Though modest, the beneficial effects of PGx for adults with moderate-severe MDD could - as a result of the scope and scale of the condition and its impacts - have important ramifications for patients and the health system.

Integration of a pharmacist-led pharmacogenomic service in a geriatric clinic: Barriers and outcomes

OBJECTIVES

The primary objective was to identify the proportion of patients who successfully completed PGx testing. Secondary objectives included determining the proportion of patients with actionable PGx results, determining the proportion of patients with a baseline medication intervention within 6 months of successfully completing PGx testing, and identifying barriers for not completing testing.

DESIGN

This was a single center, non-interventional, retrospective cohort study, approved by the institutional review board.

SETTING AND PARTICIPANTS

Patients included were 65 years of age or older and referred for PGx testing from geriatric outpatient clinics between May 1, 2019 and July 31, 2020.

OUTCOME MEASURES

This study aimed to assess the implementation of pharmacist-led pharmacogenomics (PGx) in the care of community-dwelling older adults in an outpatient clinic. Little is known about the acceptance and impact of this type of service within this population.

RESULTS

Of the 67 patients included, majority were female (78%), white (76%), and an average age of 78 years ± 5.98 SD. Majority were insured by Original Medicare or Medicaid (61%), had a history of cognitive impairment (84%), had a referring diagnosis of anxiety (40%) or depression (67%), and were prescribed a selective serotonin reuptake inhibitor (69%) at baseline. Majority successfully completed PGx testing (72%), with 72% having actionable PGx findings and 83% having a pharmacological intervention made thereafter. Nineteen patients did not complete testing (28%), with the primary barrier being not having an appointment scheduled (63%).

CONCLUSION

This study demonstrated majority of older adults were accepting of PGx testing and majority of findings were relevant to clinical care of anxiety, depression, or cognitive impairment.

The Evolving Role of Animal Models in the Discovery and Development of Novel Treatments for Psychiatric Disorders

Historically, animal models have been routinely used in the characterization of novel chemical entities (NCEs) for various psychiatric disorders. Animal models have been essential in the in vivo validation of novel drug targets, establishment of lead compound pharmacokinetic to pharmacodynamic relationships, optimization of lead compounds through preclinical candidate selection, and development of translational measures of target occupancy and functional target engagement. Yet, with decades of multiple NCE failures in Phase II and III efficacy trials for different psychiatric disorders, the utility and value of animal models in the drug discovery process have come under intense scrutiny along with the widespread withdrawal of the pharmaceutical industry from psychiatric drug discovery. More recently, the development and utilization of animal models for the discovery of psychiatric NCEs has undergone a dynamic evolution with the application of the Research Domain Criteria (RDoC) framework for better design of preclinical to clinical translational studies combined with innovative genetic, neural circuitry-based, and automated testing technologies. In this chapter, the authors will discuss this evolving role of animal models for improving the different stages of the discovery and development in the identification of next generation treatments for psychiatric disorders.

Perspectives on the Clinical Use of Pharmacogenetic Testing in Late-Life Mental Healthcare: A Survey of the American Association of Geriatric Psychiatry Membership

OBJECTIVE

To assess perspectives on pharmacogenetic (PGx) testing among members of the American Association of Geriatric Psychiatry (AAGP).

DESIGN

Cross-sectional survey.

PARTICIPANTS

Members of the AAGP.

MEASUREMENTS

Anonymous web-based survey consisting of 41 items covering experiences, indications, barriers, facilitators and ethical, legal and social implications for PGx testing.

RESULTS

A total of 124 surveys were completed (response rate = 13%). Most respondents (60%) had used PGx testing but an equal proportion (58%) was uncertain about the clinical usefulness of PGx testing in late-life mental health. Despite self-reported confidence in the ability to order and interpret PGx testing, 60% of respondents felt there was not enough clinical evidence for them to use PGx testing in their practice. This was compounded by uncertainties related to their ethical obligation and legal liability when interpreting and using (or not using) PGx testing results. Respondents strongly affirmed that clinical and legal guidelines for PGx testing in older adults are needed and would be helpful.

CONCLUSION

The findings suggest additional PGx research and physician education in late-life mental healthcare settings is required to reconcile uncertainties related to the clinical efficacy and ethico-legal aspects of PGx testing as well as address current knowledge barriers to testing uptake. These efforts would be further facilitated by the development of clinical practice guidelines to ensure equitable access to testing and standardized implementation of PGx-informed prescribing in older adults.

Pharmacist-Led Medication Evaluation Considering Pharmacogenomics and Drug-Induced Phenoconversion in the Treatment of Multiple Comorbidities: A Case Report

Pharmacogenomic (PGx) information can guide drug and dose selection, optimize therapy outcomes, and/or decrease the risk of adverse drug events (ADEs). This report demonstrates the impact of a pharmacist-led medication evaluation, with PGx assisted by a clinical decision support system (CDSS), of a patient with multiple comorbidities. Following several sub-optimal pharmacotherapy attempts, PGx testing was recommended. The results were integrated into the CDSS, which supported the identification of clinically significant drug–drug, drug–gene, and drug–drug–gene interactions that led to the phenoconversion of cytochrome P450. The pharmacist evaluated PGx results, concomitant medications, and patient-specific factors to address medication-related problems. The results identified the patient as a CYP2D6 intermediate metabolizer (IM). Duloxetine-mediated competitive inhibition of CYP2D6 resulted in phenoconversion, whereby the patient’s CYP2D6 phenotype was converted from IM to poor metabolizer for CYP2D6 co-medication. The medication risk score suggested a high risk of ADEs. Recommendations that accounted for PGx and drug-induced phenoconversion were accepted. After 1.5 months, therapy changes led to improved pain control, depression status, and quality of life, as well as increased heart rate, evidenced by patient-reported improved sleep patterns, movement, and cognition. This case highlights the pharmacist’s role in using PGx testing and a CDSS to identify and mitigate medication-related problems to optimize medication regimen and medication safety.

Research into ageing and frailty

Research into ageing covers opportunities and challenges posed by an older population, and research to understand the ageing processes across the lifespan. The evidence base for Comprehensive Geriatric Assessment (CGA) is well established and efforts should now shift to understanding how to implement its principles across different healthcare contexts. Research around syndromes common in older people has progressed with variable success; while effective therapies for falls and cognitive impairment have been identified, older people with advanced frailty have commonly been excluded from Parkinson's disease and continence research. Research to understand the mechanisms of ageing has potential to mitigate against or treat emerging sarcopenia and cognitive impairment, and thus modify frailty trajectories. Pharmacogenetics could individualise therapeutics to reduce polypharmacy. These issues can only be addressed with development of infrastructure, capacity and expertise in ageing research. Commonly used research methodologies must be adapted to take account of frailty, cognitive impairment and functional dependency.

An update on antidepressant pharmacotherapy in late-life depression

Introduction: Clinically important depressive symptoms that occur in adults over age 60 are often termed late-life depression (LLD). LLD poses challenges for treating clinicians in both detection and treatment. Antidepressants are the most common first-line treatment approach. Older adults are at an increased risk of adverse effects because of polypharmacy.Areas covered: This article summarizes the challenges and approaches when using pharmacotherapy in LLD with a focus on newer data that have become available during the last five years. While no new antidepressants have become available during this period, a review of the literature summarizes advances in the knowledge of the adverse effects associated with various antidepressants and on the potential contribution of pharmacogenetic tools when prescribing antidepressants to older patients.Expert opinion: During the past 5 years, most of the literature relevant to the pharmacotherapy of MDD in older patients has focused on adverse effects. In particular, the effects of antidepressants on cognition and bone are emerging as important areas for clinical attention and further investigation. There is also an emerging literature on the potential role of pharmacogenetic testing in patients with MDD, though recommendations for use in older adults await larger studies that demonstrate its efficacy and cost-effectiveness.

Major Depressive Disorder in Older Patients as an Inflammatory Disorder: Implications for the Pharmacological Management of Geriatric Depression

Depression is a common and highly disabling condition in older adults. It is a heterogenous disorder and there is emerging evidence of a link between inflammation and depression in older patients, with a possible inflammatory subtype of depression. Persistent low-level inflammation, from several sources including psychological distress and chronic disease, can disrupt monoaminergic and glutaminergic systems to create dysfunctional brain networks. Despite the evidence for the role of inflammation in depression, there is insufficient evidence to recommend use of any putative anti-inflammatory agent in the treatment of depression in older adults at this stage. Further characterisation of markers of inflammation and stratification of participants with elevated rates of inflammatory markers in treatment trials is needed.

Genome-wide analysis suggests the importance of vascular processes and neuroinflammation in late-life antidepressant response

Antidepressant outcomes in older adults with depression is poor, possibly because of comorbidities such as cerebrovascular disease. Therefore, we leveraged multiple genome-wide approaches to understand the genetic architecture of antidepressant response. Our sample included 307 older adults (≥60 years) with current major depression, treated with venlafaxine extended-release for 12 weeks. A standard genome-wide association study (GWAS) was conducted for post-treatment remission status, followed by in silico biological characterization of associated genes, as well as polygenic risk scoring for depression, neurodegenerative and cerebrovascular disease. The top-associated variants for remission status and percentage symptom improvement were PIEZO1 rs12597726 (OR = 0.33 [0.21, 0.51], p = 1.42 × 10^-6) and intergenic rs6916777 (Beta = 14.03 [8.47, 19.59], p = 1.25 × 10^-6), respectively. Pathway analysis revealed significant contributions from genes involved in the ubiquitin-proteasome system, which regulates intracellular protein degradation with has implications for inflammation, as well as atherosclerotic cardiovascular disease (n = 25 of 190 genes, p = 8.03 × 10^-6, FDR-corrected p = 0.01). Given the polygenicity of complex outcomes such as antidepressant response, we also explored 11 polygenic risk scores associated with risk for Alzheimer's disease and stroke. Of the 11 scores, risk for cardioembolic stroke was the second-best predictor of non-remission, after being male (Accuracy = 0.70 [0.59, 0.79], Sensitivity = 0.72, Specificity = 0.67; p = 2.45 × 10^-4). Although our findings did not reach genome-wide significance, they point to previously-implicated mechanisms and provide support for the roles of vascular and inflammatory pathways in LLD. Overall, significant enrichment of genes involved in protein degradation pathways that may be impaired, as well as the predictive capacity of risk for cardioembolic stroke, support a link between late-life depression remission and risk for vascular dysfunction.