The clinical validity and utility of combinatorial pharmacogenomics: Enhancing patient outcomes

Life-time Actionable Pharmacogenetic Drug Use: A Population-based Cohort Study in 86 040 Young People With and Without Mental Disorders in Denmark

Objective To describe life-time use of current actionable pharmacogenetic (PGx) somatic and psychotropic drugs according to international PGx consortia in people with and without hospital-diagnosed mental disorders in the Danish population.

Methods Population- and register-based observational drug utilization study in 56 065 individuals with mental disorders, i. e. attention-deficit/hyperactivity disorder, autism, bipolar disorder, depression and schizophrenia, and a random, representative sample of 29 975 individuals of the Danish population, born between 1981 and 2005. Individuals were followed from 1995 or birth until 2016 (for a maximum of 22 years). We report prevalence and incidence rates of PGx drug use by age, sex and mental disorders based on redeemed prescriptions between 1995 and 2016.

Results Of the 69 PGx drugs, prescriptions of 39 drugs had been redeemed by the study population by 35 years of age. The use of at least 1 PGx drug varied between 23.1% in males without mental disorders and 97.2% in females with schizophrenia. Males with ADHD or autism were the youngest first-time PGx drug users at a mean of 11.6 years. The mean number of different PGx drugs used was 1.2 in males without mental disorders and 5.6 in individuals with schizophrenia. The prevalence of different PGx drugs linked to more than one gene was 25.3% in males without mental disorders to 94.1% in females with schizophrenia.

Conclusion PGx drugs are commonly used by younger people, more often by individuals with mental disorders and by females. Panel-based PGx testing could contribute to treatment decisions at a very young age.

Effect of Pharmacogenetic-Based Decision Support Tools in Improving Depression Outcomes: A Systematic Review

OBJECTIVE

Evidence supporting the utility of pharmacogenetic (PGX) tests in depression is scarce. The main objectives of this study were to summarize, update, and assess the quality of the available evidence regarding PGX testing in depression as well as estimating the impact of using PGX testing tools in depression outcomes in the Middle East/North Africa (MENA) region.

METHODOLOGY

Scientific databases were systematically searched from inception to June 30, 2020 for systematic reviews and randomized controlled trials (RCTs) assessing the clinical utility of PGX tests in the treatment of depression. Meta-analyses only and RCTs that were included in eligible systematic reviews were excluded. The quality of the eligible studies was assessed using the Crowe Critical Appraisal Tool (CCAT).

RESULTS

Six systematic reviews and three RCTs met the inclusion criteria and were included in this study. The results of the systematic reviews provided weak evidence on the efficacy of PGX testing, especially in patients with moderate-severe depression at 8 weeks. In addition, there was a lack of evidence regarding safety outcomes. Newer RCTs with better quality showed clinical promise regarding efficacy outcomes, especially in patients with gene-drug interactions. No evidence was found regarding PGX testing impact in the MENA region.

CONCLUSION

This systematic review is an update and summary of the available literature on the clinical utility of PGX testing in depression. The findings of this study demonstrate that PGX testing prior to treatment initiation or during the course of therapy may improve efficacy outcomes. Further studies are warranted to assess the impact of PGX testing on safety outcomes.

An Effective Method to Facilitate Personalized and Precise Medicine for Schizophrenia Treatment Based on Pharmacogenomics

Background

Schizophrenia is a serious mental illness affecting 0.3-0.7% of the world's population. It is a classic quantitative genetic disease and is affected by a variety of common and rare genetic variants.

Methods

To facilitate personalized and precise medicine for schizophrenia treatment, we designed a program by genotyping a panel of related genes for schizophrenic patients using MassARRAY time-of-flight mass spectrometry. The program was tested in an observational clinical study conducted at the Hulunbuir Mental Health Center of China. In the study, a total of 254 patients diagnosed with schizophrenia were recruited and genotyped. The genotyping results were used to generate reports listing where the 16 included antipsychotics should be placed: "Use as directed," "Use with caution," or "Use with caution and with frequent blood concentration monitoring" categories. Seventy-two of the patients completed the 24-week follow-up observation, during which their PANSS scores were assessed at eight time points.

Results

For all of the subjects who completed the study, the PANSS scores dropped significantly, showing the effectiveness of the treatment. During the 24-week study, PANSS scores of patients whose medications were consistent (N = 48) with their genetic test results dropped from 84.3 (SD = 12.4) to 58.8 (SD = 15.3), and average PANSS change rate reached 56.1% after 24 weeks. In contrast, PANSS scores of patients with genetic tests reported as "Use with caution" or "Use with caution and with frequent blood concentration monitoring" (N = 24) dropped from 81.1 (SD = 10.5) to 63.8 (SD = 10.1), and their average PANSS change rate was 37.6%.

Conclusions

This research indicates that our pharmacogenomic-based program could be a suitable and effective tool to facilitate precise medication in schizophrenia treatment.

Pharmacogenetic genotype and phenotype frequencies in a large Danish population-based case-cohort sample

Pharmacogenetics aims to improve clinical care by studying the relationship between genetic variation and variable drug response. Large population-based datasets could improve our current understanding of pharmacogenetics from selected study populations. We provide real-world pharmacogenetic frequencies of genotypes and (combined) phenotypes of a large Danish population-based case-cohort sample (iPSYCH2012; data of the Integrative Psychiatric Research consortium). The genotyped sample consists of 77,684 individuals, of which 51,464 individuals had diagnoses of severe mental disorders (SMD case-cohort) and 26,220 were individuals randomly selected from the Danish population (population cohort). Array-based genotype data imputed to 8.4 million genetic variants was searched for a selected pharmacogenetic panel of 42 clinically relevant variants and a CYP2D6 gene deletion and duplication. We identified 19 of 42 variants. Minor allele frequencies (MAFs) were consistent with previously reported MAFs, and did not differ between SMD cases and population cohorts. Almost all individuals carried at least one genetic variant (> 99.9%) and 87% carried three or more genetic variants. When genotypes were translated into phenotypes, also > 99.9% of individuals had at least one divergent phenotype (i.e. divergent from the common phenotypes considered normal, e.g. extensive metabolizer). The high number of identified individuals with at least one pharmacogenetic variant or divergent phenotype indicates the importance of pharmacogenetic panel-based genotyping. Combined CYP2C19-CYP2D6 phenotypes revealed that 72.7% of individuals had divergent phenotypes for one or both enzymes. As CYP2D6 and CYP2C19 have an important role in the metabolism of psychotropic drugs, this indicates the relevance of pharmacogenetic testing specifically in individuals using psychotropic drugs.

Knowledge, attitude, future expectations and perceived barriers of medical students and physicians regarding pharmacogenomics in Jordan

BACKGROUND

Pharmacogenomics (PG) is a modern tool of personalising treatment protocols to improve the efficacy and safety of drug prescriptions. These benefits are offset by a slow uptake in clinical application due to a host of physician factors, patient factors and/or health system factors. Our study, thus, aimed to determine the knowledge, attitude, future expectations and perceived barriers of medical students and physicians in Jordan regarding PG testing.

METHODS

A descriptive, cross-sectional study was conducted between February and August 2019. Physicians and senior medical students from academic and non-academic institutions in North Jordan (n = 424) were surveyed. A structured, self-administered questionnaire was designed and piloted for the purpose of the study. A scoring system for each dimension assessed was calculated and presented using means. Mean scores were compared by sociodemographic and professional variables.

RESULTS

The response rate was 70.7%. The mean total PG knowledge score (±SD) was 5.42 (±1.51) out of 10, with a significantly higher mean among respondents aged <30 years (5.54 ± 1.43) compared with those ≥30 years old (5.21 ± 1.62; P = .03). The mean total PG attitude score was 21.18 (±2.58) out of 24, with significant differences by seniority levels evident (P = .03). The future expectations of PG among our sample were high, with a mean score of 10.44 (±1.64) out of 12. The top three perceived barriers in applying PG were the high cost, lack of clinical guidelines, and limited knowledge and awareness.

CONCLUSION

Physicians and medical students in Jordan have low overall knowledge, albeit strongly positive attitude and future expectations towards PG, despite the perceived high cost and lack of clinical guidelines. Thus, we strongly recommend adopting a comprehensive educational strategy that aims to integrate PG concepts into medical curricula, and promote the culture of continuous medical education about PG among practitioners.

Literature Review Concerning the Challenges of Implementing Pharmacogenetics in Primary Care Practice

Since President Obama signed the Precision Medicine Initiative in 2015, endeavors to integrate pharmacogenetics in clinical practice and psychiatric care have been evolving rapidly. The nature of general practice and psychiatric medicine, including psychopharmacotherapy and the long-term care necessary for chronic diseases, renders these fields in desperate need of the implementation of pharmacogenetics. This article presents some of the challenges facing pharmacogenetics implementation in family medicine and psychiatric care. Reputable research websites were used to extract papers, data, and lectures concerning this topic. The results reveal that three main challenges are facing this integration: the evaluation of pharmacogenetic testing in general and psychiatric practice, cost-effectiveness, and regulatory burdens. Although considerable advances are being made to address these issues, it is time to gather these efforts under one umbrella to create guidelines based on previous and upcoming research.

Pharmacogenetic Tests in Reducing Accesses to Emergency Services and Days of Hospitalization in Bipolar Disorder: A 2-Year Mirror Analysis

Despite the enormous costs associated to mood disorders', few studies evaluate potential cost saving from the use of pharmacogenetic tests (PGT). This study compares 12 months before the execution of the PGT versus 12 months after, in terms of number and days of hospitalization and accesses to emergency services, in a sample of 30 patients affected by bipolar disorder. Secondarily, the study gives an economic value to the data based on the diagnosis-related group (DRG). Patients included in the study were required to be aged ≥18 years, sign an informed consent, have a score of Clinical Global Impression item Severity (CGIs) ≥3, and have a discordant therapy compared to the PGT in the 12 months preceding it and a therapy consistent with it for the following 12 months. Cost saving has been evaluated by paired t-tests in a mirror analysis. Statistically significant differences in all the comparisons (p < 0.0001) emerged. Important cost saving emerged after the use of PGT (€148,920 the first year versus €39,048 the following year). Despite the small sample size and lack of a control group in this study, the potential role of PGT in cost saving for the treatment of bipolar disorder treatment emerged. To confirm this result, larger and clinical trials are needed.

Difficult-to-treat depression: A clinical and research roadmap for when remission is elusive

OBJECTIVES

The report considers the pros and cons of the most commonly used conceptual model that forms the basis for most clinical practice guidelines for depression. This model promotes the attainment of sustained symptom remission as the treatment goal based on its well-established prognostic and functional importance. Sustained remission is very unlikely, however, after multiple treatment attempts. Our current model propels many clinicians to continue to change or add treatments despite little chance for remission or full functional restoration and despite the increasing risk of more adverse events from polypharmacy. An alternative 'difficult-to-treat depression' model is presented and considered. It accepts that the treatment aims for some depressed patients may shift to optimal symptom control rather than remission. When difficult-to-treat depression is suspected, the many treatable causes of persistent depression must be assessed and addressed (given the importance of remission when attainable) before difficult-to-treat depression can be ascribed. The clinical and research implications of the difficult-to-treat depression model are discussed.

CONCLUSION

Suspected difficult-to-treat depression provides a practical basis for considering when to conduct a comprehensive evaluation. Once difficult-to-treat depression is confirmed, treatment may better focus on optimal disease management (symptom control and functional improvement).

Horizon Scan Of Clinical Laboratories Offering Pharmacogenetic Testing

Pharmacogenetic (PGx) testing involves the analysis of genes known to affect response to medications. The field has been projected as a leading application of personalized or precision medicine, but the use of PGx tests has been stymied, in part, by the lack of clinical evidence of utility and reported low provider awareness. Another factor is the availability of testing. The range and types of PGx tests available have not been assessed to date. In the period September 2017-January 2018 we analyzed the numbers and types of PGx tests offered by clinical testing laboratories in the US. Of the 111 such labs that we identified, we confirmed that 76 offered PGx testing services. Of these, 31 offered only tests for single genes; 30 offered only tests for multiple genes; and 15 offered both types of tests. Collectively, 45 laboratories offered 114 multigene panel tests covering 295 genes. The majority of these tests did not have any clinical guidelines. PGx tests vary in type and makeup, which presents challenges in appropriate test evaluation and selection for providers, insurers, health systems, and patients alike.

Pharmacogenetic tests and depressive symptom remission: a meta-analysis of randomized controlled trials

Aim: To conducted a systematic review and meta-analysis of prospective, randomized controlled trials (RCTs) that examined pharmacogenetic-guided decision support tools (DSTs) relevant to depressive symptom remission in major depressive disorder (MDD). Patients & methods: Random-effects meta-analysis was performed on RCTs that examined the effect of DSTs on remission rates in MDD. RCT quality was assessed using the Cochrane Collaboration Criteria. Results & conclusion: A total of 1737 eligible subjects from five RCTs were examined. Individuals receiving pharmacogenetic-guided DST therapy (n = 887) were 1.71 (95% CI: 1.17–2.48; p = 0.005) times more likely to achieve symptom remission relative to individuals who received treatment as usual (n = 850). Pharmacogenetic-guided DSTs might improve symptom remission among those with MDD.

A Pharmacogenomic-based Antidepressant Treatment for Patients with Major Depressive Disorder: Results from an 8-week, Randomized, Single-blinded Clinical Trial

Objective

Pharmacogenomic-based antidepressant treatment (PGATx) may result in more precise pharmacotherapy of major depressive disorder (MDD) with better drug therapy guidance.

Methods

An 8-week, randomized, single-blind clinical trial was conducted to evaluate the effectiveness and tolerability of PGATx in 100 patients with MDD. All recruited patients were randomly allocated either to PGATx (n=52) or treatment as usual (TAU, n=48) groups. The primary endpoint was a change of total score of the Hamilton Depression Rating Scale-17 (HAMD-17) from baseline to end of treatment. Response rate (at least 50% reduction in HAMD-17 score from baseline), remission rate (HAMD-17 score ≥7 at the end of treatment) as well as the change of total score of Frequency, Intensity, and Burden of Side Effects Ratings (FIBSER) from baseline to end of treatment were also investigated.

Results

The mean change of HAMD-17 score was significantly different between two groups favoring PGATx by −4.1 point of difference (p=0.010) at the end of treatment. The mean change in the FIBSER score from baseline was significantly different between two treatment groups favoring PGATx by −2.5 point of difference (p=0.028). The response rate (71.7 % vs. 43.6%, p=0.014) were also significantly higher in PGATx than in TAU at the end of treatment, while the remission rate was numerically higher in PGATx than in TAU groups without statistical difference (45.5% vs. 25.6%, p=0.071). The reason for early drop-out associated with adverse events was also numerically higher in TAU (n=9, 50.0%) than in PGATx (n=4, 30.8%).

Conclusion

The present study clearly demonstrate that PGATx may be a better treatment option in the treatment of MDD in terms of effectiveness and tolerability; however, study shortcomings may limit a generalization. Adequately-powered, well-designed, subsequent studies should be mandatory to prove its practicability and clinical utility for routine practice.

The impact of real-world cardiovascular-related pharmacogenetic testing in an insured population

BACKGROUND

Pharmacogenomics is intended to help clinicians provide the right drug to the right patient at an appropriate dose. However, limited evidence of clinical utility has slowed uptake of pharmacogenomic testing (PGT).

OBJECTIVE

To evaluate the impact of real-world cardiovascular (CV)-related PGT on clinical outcomes, healthcare resource utilisation (HCRU) and cost in a large, heterogeneous population.

METHODS

Individuals with Medicare Advantage Prescription Drug, Medicaid, or commercial coverage between 1/1/2011 and 9/30/2015 and ≥1 atherosclerotic CV-related diagnosis were identified. Those with ≥1 claim for CV-related PGT were included in the test group (index date = 1st PGT claim) and matched 1:2 to controls without PGT. Individuals aged <22 or ≥90 years old on the index date, with <12 months continuous enrollment before and after the index date, or without an ASCVD-related diagnosis in the 12-month pre-index period were excluded. The primary outcome was occurrence of a major CV event during the 12-month post-index period.

RESULTS

After adjustment, the PGT group was significantly more likely to experience ischaemic stroke, pulmonary embolism, deep vein thrombosis or a composite event compared with controls. Adjusting for baseline characteristics, HCRU was significantly higher for the test group across all measured outcomes except all-cause and ASCVD-related inpatient admissions. Median all-cause and ASCVD-related healthcare costs were significantly higher for the test group.

CONCLUSIONS

Real world PGT in a large population did not improve outcomes. Tailoring medication therapy to each patient holds great promise for providing quality care but a deeper understanding of how widespread utilisation of PGT might impact objective health outcomes is needed.

Point-of-care companion diagnostic tests for personalizing psychiatric medications: fulfilling an unmet clinical need

Over the last decade stable isotope-labeled substrates have been used as probes for rapid, point-of-care, non-invasive and user-friendly phenotype breath tests to evaluate activity of drug metabolizing enzymes. These diagnostic breath tests can potentially be used as companion diagnostics by physicians to personalize medications, especially psychiatric drugs with narrow therapeutic windows, to monitor the progress of disease severity, medication efficacy and to study in vivo the pharmacokinetics of xenobiotics. Several genotype tests have been approved by the FDA over the last 15 years for both cytochrome P450 2D6 and 2C19 enzymes, however they have not been cleared for use in personalizing medications since they fall woefully short in identifying all non-responders to drugs, especially for the CYP450 enzymes. CYP2D6 and CYP2C19 are among the most extensively studied drug metabolizing enzymes, involved in the metabolism of approximately 30% of FDA-approved drugs in clinical use, associated with large individual differences in medication efficacy or tolerability essentially due to phenoconversion. The development and commercialization via FDA approval of the non-invasive, rapid (<60 min), in vivo, phenotype diagnostic breath tests to evaluate polymorphic CYP2D6 and CYP2C19 enzyme activity by measuring exhaled ¹³CO₂ as a biomarker in breath will effectively resolve the currently unmet clinical need for individualized psychiatric drug therapy. Clinicians could personalize treatment options for patients based on the CYP2D6 and CYP2C19 phenotype by selecting the optimal medication at the right initial and subsequent maintenance dose for the desired clinical outcome (i.e. greatest efficacy and minimal side effects).

Seeking an objective diagnosis of depression

Major depressive disorder (MDD: unipolar depression) is widely distributed in the USA and world-wide populations and it is one of the leading causes of disability in both adolescents and adults. Traditional diagnostic approaches for MDD are based on patient interviews, which provide a subjective assessment of clinical symptoms which are frequently shared with other maladies. Reliance upon clinical assessments and patient interviews for diagnosing MDD is frequently associated with misdiagnosis and suboptimal treatment outcomes. As such, there is increasing interest in the identification of objective methods for the diagnosis of depression. Newer technologies from genomics, transcriptomics, proteomics, metabolomics and imaging are technically sophisticated and objective but their application to diagnostic tests in psychiatry is still emerging. This brief overview evaluates the technical basis for these technologies and discusses how the extension of their clinical performance can lead to an objective diagnosis of MDD.

Genetics of Common Antipsychotic-Induced Adverse Effects

The effectiveness of antipsychotic drugs is limited due to accompanying adverse effects which can pose considerable health risks and lead to patient noncompliance. Pharmacogenetics (PGx) offers a means to identify genetic biomarkers that can predict individual susceptibility to antipsychotic-induced adverse effects (AAEs), thereby improving clinical outcomes. We reviewed the literature on the PGx of common AAEs from 2010 to 2015, placing emphasis on findings that have been independently replicated and which have additionally been listed to be of interest by PGx expert panels. Gene-drug associations meeting these criteria primarily pertain to metabolic dysregulation, extrapyramidal symptoms (EPS), and tardive dyskinesia (TD). Regarding metabolic dysregulation, results have reaffirmed HTR2C as a strong candidate with potential clinical utility, while MC4R and OGFR1 gene loci have emerged as new and promising biomarkers for the prediction of weight gain. As for EPS and TD, additional evidence has accumulated in support of an association with CYP2D6 metabolizer status. Furthermore, HSPG2 and DPP6 have been identified as candidate genes with the potential to predict differential susceptibility to TD. Overall, considerable progress has been made within the field of psychiatric PGx, with inroads toward the development of clinical tools that can mitigate AAEs. Going forward, studies placing a greater emphasis on multilocus effects will need to be conducted.