From evidence based medicine to mechanism based medicine. Reviewing the role of pharmacogenetics

Design and methods of the 'monitoring outcomes of psychiatric pharmacotherapy' (MOPHAR) monitoring program - a study protocol

Background

At many outpatient departments for psychiatry worldwide, standardized monitoring of the safety of prescribed psychotropic drugs is not routinely performed in daily clinical practice. Therefore it is unclear to which extent the drugs used by psychiatric outpatients are prescribed effectively and safely. These issues warrant structured monitoring of medication use, (pre-existing) co-morbidities, effectiveness and side effects during psychiatric outpatient treatment. Improvement of monitoring practices provides an opportunity to ensure that somatic complications and adverse drug effects are detected and dealt with in a timely manner. Structural support for data collection and follow-up tests seems essential for improvement of monitoring practices in psychiatric outpatients. The implementation of a structured somatic monitoring program as part of routine clinical practice, as we describe in this study protocol, may be a solution.

Methods

In order to address these issues, we developed the innovative program ‘Monitoring Outcomes of Psychiatric Pharmacotherapy (MOPHAR)’. MOPHAR is an infrastructure for implementation of standardized routine outcome monitoring (ROM; including standardized monitoring of treatment effect), monitoring of adverse psychotropic medication effects in psychiatric outpatients, encompassing both somatic adverse effects (e.g. metabolic disturbances) and subjective adverse effects (e.g. sedation or sexual side effects) and medication reconciliation.

Discussion

In the MOPHAR monitoring program, a nurse performs general and psychotropic drug-specific somatic screenings and provides the treating mental health care providers with more and better information on somatic monitoring for treatment decisions. Given our experience regarding implementation of the MOPHAR program, we expect that the MOPHAR program is feasible and beneficial for patients in any MHS organisation. This paper describes the objectives, target population, setting and the composition and roles of the treatment team. It also indicates what measurements are performed at which time points during outpatient treatment in the MOPHAR monitoring program, as well as the research aspects of this project.

Trial registration

MOPHAR research has been prospectively registered with the Netherlands Trial Register on 19th of November 2014. (NL4779).

Electronic supplementary material

The online version of this article (10.1186/s12913-019-3951-2) contains supplementary material, which is available to authorized users.

Usefulness of Pharmacogenetic Analysis in Psychiatric Clinical Practice: A Case Report

There are many factors involved in the effectiveness and efficiency of psychiatric drug treatment. One of them is psychotropic drug metabolism, which takes place mostly in the liver through the P450 enzyme system. However, there are genotypic variants of this system’s enzymes that can directly affect both the efficacy and the onset of side effects of a given therapeutic regimen. These genotypic changes could partly explain the lack of efficacy of treatment in certain patients. We report the case of a patient diagnosed with bipolar type I disorder that presented multiple and frequent manic episodes in which the efficacy and tolerability of several pharmacological regimens with mood stabilizers and antipsychotics was scarce. The choice of medical treatment should be based on its efficacy and side effect profile. This decision can be made more accurately using the information provided by pharmacogenetic analysis. This case illustrates the importance of pharmacogenetic studies in clinical practice. The results of pharmacogenetic analysis helped to decide on a better treatment plan to achieve clinical improvement and reduce drug-induced adverse effects.

Evidence for Clinical Implementation of Pharmacogenomics in Cardiac Drugs

OBJECTIVE

To comprehensively assess the pharmacogenomic evidence of routinely used drugs for clinical utility.

METHODS

Between January 2, 2011, and May 31, 2013, we assessed 71 drugs by identifying all drug/genetic variant combinations with published clinical pharmacogenomic evidence. Literature supporting each drug/variant pair was assessed for study design and methods, outcomes, statistical significance, and clinical relevance. Proposed clinical summaries were formally scored using a modified AGREE (Appraisal of Guidelines for Research and Evaluation) II instrument, including recommendation for or against guideline implementation.

RESULTS

Positive pharmacogenomic findings were identified for 51 of 71 cardiovascular drugs (71.8%), representing 884 unique drug/variant pairs from 597 publications. After analysis for quality and clinical relevance, 92 drug/variant pairs were proposed for translation into clinical summaries, encompassing 23 drugs (32.4% of drugs reviewed). All were recommended for clinical implementation using AGREE II, with mean ± SD overall quality scores of 5.18±0.91 (of 7.0; range, 3.67-7.0). Drug guidelines had highest mean ± SD scores in AGREE II domain 1 (Scope) (91.9±6.1 of 100) and moderate but still robust mean ± SD scores in domain 3 (Rigor) (73.1±11.1), domain 4 (Clarity) (67.8±12.5), and domain 5 (Applicability) (65.8±10.0). Clopidogrel (CYP2C19), metoprolol (CYP2D6), simvastatin (rs4149056), dabigatran (rs2244613), hydralazine (rs1799983, rs1799998), and warfarin (CYP2C9/VKORC1) were distinguished by the highest scores. Seven of the 9 most commonly prescribed drugs warranted translation guidelines summarizing clinical pharmacogenomic information.

CONCLUSION

Considerable clinically actionable pharmacogenomic information for cardiovascular drugs exists, supporting the idea that consideration of such information when prescribing is warranted.

Is a high maintenance dose of clopidogrel suitable for overcoming clopidogrel resistance in patients?

BACKGROUND

A double maintenance dose of clopidogrel at 150 mg daily has been suggested as an effective alternative treatment for patients who have clopidogrel resistance.

OBJECTIVE

To determine if a double maintenance dose of clopidogrel can overcome the low drug response rate observed in patients who have clopidogrel resistance while on a 75 mg daily standard maintenance dose of clopidogrel.

METHODS

A retrospective analysis was conducted in South Korean patients who underwent a platelet function test and received a double maintenance dose of clopidogrel at a secondary medical institution between January 2011 and June 2012. The primary endpoint was to assess clopidogrel response using an adenosine diphosphate test after a double maintenance dose of clopidogrel. The secondary endpoint was the presence of factors that could affect response to clopidogrel.

RESULTS

Of 389 patients identified, 77 patients were eligible for this study. Values from the adenosine diphosphate test decreased significantly in 63 patients (82%) after a double maintenance dose of clopidogrel (p < 0.001). A total of 37 patients (48%) overcame clopidogrel resistance. Concurrent disease appeared to be a contributory factor in clopidogrel resistance.

CONCLUSION

A double maintenance dose of clopidogrel at 150 mg daily was associated with a reduction in adenosine diphosphate-induced platelet aggregation in South Korean patients who previously exhibited clopidogrel resistance.

Identification of potential biomarkers of hepatitis B-induced acute liver failure using hepatic cells derived from human skin precursors

Besides their role in the elucidation of pathogenic processes of medical and pharmacological nature, biomarkers can also be used to document specific toxicological events. Hepatic cells generated from human skin-derived precursors (hSKP-HPC) were previously shown to be a promising in vitro tool for the evaluation of drug-induced hepatotoxicity. In this study, their capacity to identify potential liver-specific biomarkers at the gene expression level was investigated with particular emphasis on acute liver failure (ALF). To this end, a set of potential ALF-specific biomarkers was established using clinically relevant liver samples obtained from patients suffering from hepatitis B-associated ALF. Subsequently, this data was compared to data obtained from primary human hepatocyte cultures and hSKP-HPC, both exposed to the ALF-inducing reference compound acetaminophen. It was found that both in vitro systems revealed a set of molecules that was previously identified in the ALF liver samples. Yet, only a limited number of molecules was common between both in vitro systems and the ALF liver samples. Each of the in vitro systems could be used independently to identify potential toxicity biomarkers related to ALF. It seems therefore more appropriate to combine primary human hepatocyte cultures with complementary in vitro models to efficiently screen out potential hepatotoxic compounds.

Pharmacogenetic biomarkers for predicting drug response

Drug response shows significant interpatient variability and evidence that genetics influences outcome of drug therapy has been known for more than five decades. However, the translation of this knowledge to clinical practice remains slow. Using examples from clinical practice six considerations about the implementation of pharmacogenetics (PGx) into routine care are discussed: the need for PGx biomarkers; the sources of genetic variability in drug response; the amount of variability explained by PGx; whether PGx test results are actionable; the level of evidence needed for implementation of PGx and the sources of information regarding interpretation of PGx data.

Stem cell-derived hepatocytes as a predictive model for drug-induced liver injury: are we there yet?

Amongst the different types of adverse drug reactions, drug-induced liver injury is the most prominent cause of patient morbidity and mortality. However, the current available hepatic model systems developed for evaluating safety have limited utility and relevance as they do not fully recapitulate a fully functional hepatocyte, and do not sufficiently represent the genetic polymorphisms present in the population. The rapidly advancing research in stem cells raises the possibility of using human pluripotent stem cells in bridging this gap. The generation of human induced pluripotent stem cells via reprogramming of mature human somatic cells may also allow for disease modelling in vitro for the purposes of assessing drug safety and toxicology. This would also allow for better understanding of disease processes and thus facilitate in the potential identification of novel therapeutic targets. This review will focus on the current state of effort to derive hepatocytes from human pluripotent stem cells for potential use in hepatotoxicity evaluation and aims to provide an insight as to where the future of the field may lie.

Frequency and outcomes of concomitant use of proton pump inhibitors and clopidogrel after hospital discharge

OBJECTIVE

To assess the frequency of concomitant use of proton pump inhibitors (PPI) in patients treated with clopidogrel, and the potential impact of this use on cardiovascular events.

METHOD

Three-month prospective observational study. All patients taking clopidogrel who were admitted to the study hospital were included in the study. They were split into categories based on whether they had taken the drug concomitantly with PPI upon admission, upon discharge or during follow-up, or if they had not taken the two drugs together at all. Any post-discharge readmissions for cardiovascular events in the three months following the original admission were also recorded.

RESULTS

A total of 134 patients were included in the study. Only 26 patients (19,6%) did not take any PPI. Among 14 patients (10.5%) readmitted because of a cardiovascular event, 13 were taking clopidogrel concomitantly with a PPI (not statistically significant). Most of the readmitted patients presented other risk factors potentially related with cardiovascular events.

CONCLUSION

This study underlines a high concomitant use of PPI with clopidogrel, with no evidence of an increasing risk of readmission due to cardiovascular event potentially related to a drug-drug interaction between these drugs. The study did not identify any readmission related to a gastro-intestinal complication.

Avoiding Serotonin Syndrome: The Nature of the Interaction Between Tramadol and Selective Serotonin Reuptake Inhibitors

Objective:

To investigate the nature of the interaction between selective serotonin reuptake inhibitors (SSRIs) and tramadol to mitigate or avoid serotonin syndrome.

Data Sources:

PubMed, Ovid MEDLINE, and International Pharmaceutical Abstracts from January 1990 to August 2012 were searched. Key words used were tramadol, antidepressive agents, antidepressants, drug interactions, selective serotonin uptake inhibitors, and serotonin syndrome.

Study Selection and Data Extraction:

Only English-language studies were included. No randomized controlled trials were identified. Review articles, case reports, and 1 case series that identified the scope of interaction between tramadol and SSRIs were evaluated. Review articles evaluating the role of pharmacogenetics in the use of tramadol, SSRIs, and serotonin syndrome were also reviewed.

Data Synthesis:

Published documentation describing the interaction between tramadol and SSRIs and its relevance to serotonin syndrome is limited to a few case reports and 1 case series. While both tramadol and SSRIs increase the amount of serotonin in the brain, the interaction is much more complicated. Tramadol is metabolized through CYP2D6 enzymes and all SSRIs are inhibitors of these enzymes. Inhibitors of CYP2D6 can increase the concentration of tramadol in the blood and thus increase its effects on serotonin in the brain, contributing to the development of serotonin syndrome. CYP2D6 poor metabolizers are at a greater risk of serotonin syndrome and an inadequate analgesic effect.

Conclusions:

Coadministration of tramadol and SSRIs has caused serotonin syndrome. An attempt should be made to identify individuals who are poor metabolizers of CYP2D6 and avoid this combination in those patients. When SSRIs and tramadol must be used in combination, it is critical that patients be aware of the signs and symptoms of serotonin syndrome, should they occur.

Atorvastatin-related rhabdomyolysis and acute renal failure in a genetically predisposed patient with potential drug-drug interaction

CASE DESCRIPTION

A 75-year-old man developed rhabdomyolysis and acute renal failure during atorvastatin therapy. All medications were discontinued and the patient was treated with intermittent hemodialysis throughout the course of hospitalization. After four weeks, patient's kidney function tests and serum myoglobin levels decreased to normal values and muscle weakness gradually disappeared. Genotyping results showed that the patient had a single-nucleotide polymorphism within genes encoding the organic anion-transporting polypeptide 1B1 and ATP binding cassette sub-family B member 1, which predisposed him for statin-induced myopathy. He was also a poor metabolizer of cytochrome P450 2C19. Concomitant therapy with pantoprazole could have resulted in the inhibition of cytochrome P450 3A4-mediated metabolism of atorvastatin and contributed to the development of rhabdomyolysis.

CONCLUSION

The case illustrates the clinical relevance and relationship between pharmacogenetic and pharmacokinetic factors in the development of statin-induced myopathy.

Personalized medicine: a competitor or an upgrade of evidence-based medicine?

Evidence-based medicine is a method of healthcare decision-making that intends to combine the most reliable scientific information with individual expertise and patient preferences in order to offer the optimal diagnostic and therapeutic option for the patient. In recent years, the term personalized medicine has been introduced to represent an approach considering differences among individual patients. In modern medicine the most important sources of evidence are clinical trials using epidemiological methods, and molecular biological and genetic methods characterizing individual patients. Responses to a certain therapeutic intervention differ among patients for several reasons. Identifying benefits and harms of an intervention can be handled by two approaches. The first is a statistical approach using the rule of large numbers, resulting in statistically meaningful conclusions. The other approach is personalized: the conclusions are valid for individual patients or subgroups identified by well-defined markers. Whether the evidence is statistical deriving from a large number of clinical observations or personalized based on molecular studies - it should be scientifically sound to apply in clinical practice. Confronting evidence-based medicine with personalized medicine would be justified only if the former is misinterpreted and restricted only to the use of randomized trials and their systematic reviews. The practice of personalized medicine is also based on evidence, and in many instances evidence from molecular research is also statistical in nature. Regarding healthcare decision about an individual patient, whether using evidence from randomized trials or from molecular studies of biomarkers, we have to base our decisions on reliable, good quality evidence. Evidence from molecular and genetic medicine thus improves the armament of evidence-based medicine, and this upgrade yields a more reliable support for our decisions in everyday practice.

Human pluripotent stem cells for modeling toxicity

The development of xenobiotics, driven by the demand for therapeutic, domestic and industrial uses continues to grow. However, along with this increasing demand is the risk of xenobiotic-induced toxicity. Currently, safety screening of xenobiotics uses a plethora of animal and in vitro model systems which have over the decades proven useful during compound development and for application in mechanistic studies of xenobiotic-induced toxicity. However, these assessments have proven to be animal-intensive and costly. More importantly, the prevalence of xenobiotic-induced toxicity is still significantly high, causing patient morbidity and mortality, and a costly impediment during drug development. This suggests that the current models for drug safety screening are not reliable in toxicity prediction, and the results not easily translatable to the clinic due to insensitive assays that do not recapitulate fully the complex phenotype of a functional cell type in vivo. Recent advances in the field of stem cell research have potentially allowed for a readily available source of metabolically competent cells for toxicity studies, derived using human pluripotent stem cells harnessed from embryos or reprogrammed from mature somatic cells. Pluripotent stem cell-derived cell types also allow for potential disease modeling in vitro for the purposes of drug toxicology and safety pharmacology, making this model possibly more predictive of drug toxicity compared with existing models. This article will review the advances and challenges of using human pluripotent stem cells for modeling metabolism and toxicity, and offer some perspectives as to where its future may lie.

Population sciences, translational research, and the opportunities and challenges for genomics to reduce the burden of cancer in the 21st century

Advances in genomics and related fields are promising tools for risk assessment, early detection, and targeted therapies across the entire cancer care continuum. In this commentary, we submit that this promise cannot be fulfilled without an enhanced translational genomics research agenda firmly rooted in the population sciences. Population sciences include multiple disciplines that are needed throughout the translational research continuum. For example, epidemiologic studies are needed not only to accelerate genomic discoveries and new biological insights into cancer etiology and pathogenesis, but to characterize and critically evaluate these discoveries in well-defined populations for their potential for cancer prediction, prevention and response to treatment. Behavioral, social, and communication sciences are needed to explore genomic-modulated responses to old and new behavioral interventions, adherence to therapies, decision making across the continuum, and effective use in health care. Implementation science, health services, outcomes research, comparative effectiveness research, and regulatory science are needed for moving validated genomic applications into practice and for measuring their effectiveness, cost-effectiveness, and unintended consequences. Knowledge synthesis, evidence reviews, and economic modeling of the effects of promising genomic applications will facilitate policy decisions and evidence-based recommendations. Several independent and multidisciplinary panels have recently made specific recommendations for enhanced research and policy infrastructure to inform clinical and population research for moving genomic innovations into the cancer care continuum. An enhanced translational genomics and population sciences agenda is urgently needed to fulfill the promise of genomics in reducing the burden of cancer.

Genetic testing for early detection of individuals at risk of coronary heart disease and monitoring response to therapy: challenges and promises

Coronary heart disease (CHD) often presents suddenly with little warning. Traditional risk factors are inadequate to identify the asymptomatic high-risk individuals. Early identification of patients with subclinical coronary artery disease using noninvasive imaging modalities would allow the early adoption of aggressive preventative interventions. Currently, it is impractical to screen the entire population with noninvasive coronary imaging tools. The use of relatively simple and inexpensive genetic markers of increased CHD risk can identify a population subgroup in which benefit of atherosclerotic imaging modalities would be increased despite nominal cost and radiation exposure. Additionally, genetic markers are fixed and need only be measured once in a patient's lifetime, can help guide therapy selection, and may be of utility in family counseling.

Bioinformatics challenges for personalized medicine

MOTIVATION

Widespread availability of low-cost, full genome sequencing will introduce new challenges for bioinformatics.

RESULTS

This review outlines recent developments in sequencing technologies and genome analysis methods for application in personalized medicine. New methods are needed in four areas to realize the potential of personalized medicine: (i) processing large-scale robust genomic data; (ii) interpreting the functional effect and the impact of genomic variation; (iii) integrating systems data to relate complex genetic interactions with phenotypes; and (iv) translating these discoveries into medical practice.

CONTACT

russ.altman@stanford.edu