Pharmacogenetic-guided selection of warfarin versus novel oral anticoagulants for stroke prevention in patients with atrial fibrillation: a cost-effectiveness analysis

Assessing the utility of measurement methods applied in economic evaluations of pharmacogenomics applications

An increasing number of economic evaluations are published annually investigating the economic effectiveness of pharmacogenomic (PGx) testing. This work was designed to provide a comprehensive summary of the available utility methods used in cost-effectiveness/cost-utility analysis studies of PGx interventions. A comprehensive review was conducted to identify economic analysis studies using a utility valuation method for PGx testing. A total of 82 studies met the inclusion criteria. A majority of studies were from the USA and used the EuroQol-5D questionnaire, as the utility valuation method. Cardiovascular disorders was the most studied therapeutic area while discrete-choice studies mainly focused on patients' willingness to undergo PGx testing. Future research in applying other methodologies in PGx economic evaluation studies would improve the current research environment and provide better results.

Global distribution of functionally important CYP2C9 alleles and their inferred metabolic consequences

BACKGROUND

Genetic variability in the cytochrome P450 CYP2C9 constitutes an important predictor for efficacy and safety of various commonly prescribed drugs, including coumarin anticoagulants, phenytoin and multiple non-steroidal anti-inflammatory drugs (NSAIDs). A global map of CYP2C9 variability and its inferred functional consequences has been lacking.

RESULTS

Frequencies of eight functionally relevant CYP2C9 alleles (*2, *3, *5, *6, *8, *11, *13 and *14) were analyzed. In total, 108 original articles were identified that included genotype data from a total of 81,662 unrelated individuals across 70 countries and 40 unique ethnic groups. The results revealed that CYP2C9*2 was most abundant in Europe and the Middle East, whereas CYP2C9*3 was the main reason for reduced CYP2C9 activity across South Asia. Our data show extensive variation within superpopulations with up to tenfold differences between geographically adjacent populations in Malaysia, Thailand and Vietnam. Translation of genetic CYP2C9 variability into functional consequences indicates that up to 40% of patients in Southern Europe and the Middle East might benefit from warfarin and phenytoin dose reductions, while 3% of patients in Southern Europe and Israel are recommended to reduce starting doses of NSAIDs.

CONCLUSIONS

This study provides a comprehensive map of the genetic and functional variability of CYP2C9 with high ethnogeographic resolution. The presented data can serve as a useful resource for CYP2C9 allele and phenotype frequencies and might guide the optimization of genotyping strategies, particularly for indigenous and founder populations with distinct genetic profiles.

Cost Effectiveness of Pharmacogenetic Testing for Drugs with Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines: A Systematic Review

The objective of this study was to evaluate the evidence on cost-effectiveness of pharmacogenetic (PGx)-guided treatment for drugs with Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines. A systematic review was conducted using multiple biomedical literature databases from inception to June 2021. Full articles comparing PGx-guided with nonguided treatment were included for data extraction. Quality of Health Economic Studies (QHES) was used to assess robustness of each study (0-100). Data are reported using descriptive statistics. Of 108 studies evaluating 39 drugs, 77 (71%) showed PGx testing was cost-effective (CE) (N = 48) or cost-saving (CS) (N = 29); 21 (20%) were not CE; 10 (9%) were uncertain. Clopidogrel had the most articles (N = 23), of which 22 demonstrated CE or CS, followed by warfarin (N = 16), of which 7 demonstrated CE or CS. Of 26 studies evaluating human leukocyte antigen (HLA) testing for abacavir (N = 8), allopurinol (N = 10), or carbamazepine/phenytoin (N = 8), 15 demonstrated CE or CS. Nine of 11 antidepressant articles demonstrated CE or CS. The median QHES score reflected high-quality studies (91; range 48-100). Most studies evaluating cost-effectiveness favored PGx testing. Limited data exist on cost-effectiveness of preemptive and multigene testing across disease states.

Population genetic polymorphisms of pharmacogenes in Zimbabwe, a potential guide for the safe and efficacious use of medicines in people of African ancestry

OBJECTIVE

Pharmacogenomics (PGx) is a clinically significant factor in the safe and efficacious use of medicines. While PGx knowledge is abundant for other populations, there are scarce PGx data on African populations and is little knowledge on drug-gene interactions for medicines used to treat diseases common in Africa. The aim of this study was to use a custom-designed open array to genotype clinically actionable variants in a Zimbabwean population. This study also identified some of the commonly used drugs in Zimbabwe and the associated genes involved in their metabolism.

METHODS

A custom-designed open array that covers 120 genetic variants was used to genotype 522 black Zimbabwean healthy volunteers using TaqMan-based single nucleotide polymorphism genotyping. Data were also accessed from Essential Drugs' List in Zimbabwe (EDLIZ), and the medicines were grouped into the associated biomarker groups based on their metabolism. We also estimated the national drug procurement levels for medicines that could benefit from PGx-guided use based on the data obtained from the national authorities in Zimbabwe.

RESULTS

The results demonstrate the applicability of an open-array chip in simultaneously determining multiple genetic variants in an individual, thus significantly reducing cost and time to generate PGx data. There were significantly high frequencies of African-specific variants, such as the CYP2D6*17 and *29 variants and the CYP2B6*18 variant. The data obtained showed that the Zimbabwean population exhibits PGx variations in genes important for the safe and efficacious use of drugs approved by the EDLIZ and are procured at significantly large amounts annually. The study has established a cohort of genotyped healthy volunteers that can be accessed and used in the conduct of clinical pharmacogenetic studies for drugs entering a market of people of predominantly African ancestry.

CONCLUSION

Our study demonstrated the potential benefit of integrating PGx in Zimbabwe for the safe and efficacious use of drugs that are commonly used.

Ethnic Diversity and Warfarin Pharmacogenomics

Warfarin has remained the most commonly prescribed vitamin K oral anticoagulant worldwide since its approval in 1954. Dosing challenges including having a narrow therapeutic window and a wide interpatient variability in dosing requirements have contributed to making it the most studied drug in terms of genotype-phenotype relationships. However, most of these studies have been conducted in Whites or Asians which means the current pharmacogenomics evidence-base does not reflect ethnic diversity. Due to differences in minor allele frequencies of key genetic variants, studies conducted in Whites/Asians may not be applicable to underrepresented populations such as Blacks, Hispanics/Latinos, American Indians/Alaska Natives and Native Hawaiians/other Pacific Islanders. This may exacerbate health inequalities when Whites/Asians have better anticoagulation profiles due to the existence of validated pharmacogenomic dosing algorithms which fail to perform similarly in the underrepresented populations. To examine the extent to which individual races/ethnicities are represented in the existing body of pharmacogenomic evidence, we review evidence pertaining to published pharmacogenomic dosing algorithms, including clinical utility studies, cost-effectiveness studies and clinical implementation guidelines that have been published in the warfarin field.

Genetic-Guided Pharmacotherapy for Atrial Fibrillation: A Systematic and Critical Review of Economic Evaluations

OBJECTIVES

This study aimed to examine the extent and quality of evidence from economic evaluations (EEs) of genetic-guided pharmacotherapy (PGx) for atrial fibrillation (AF) and to identify variables influential in changing base-case conclusions.

METHODS

From systematic searches, we included EEs of existing PGx testing to guide pharmacotherapy for AF, without restrictions on population characteristics or language. Articles excluded were genetic tests used to guide device-based therapy or focused on animals.

RESULTS

We found 18 EEs (46 comparisons), all model-based cost-utility analysis with or without cost-effectiveness analysis mostly from health system's perspectives, of PGx testing to determine coumadin/direct-acting anticoagulant (DOAC) dosing (14 of 18), to stratify patients into coumadin/DOACs (3 of 18), or to increase patients' adherence to coumadin (1 of 18) versus non-PGx. Most PGx to determine coumadin dosing found PGx more costly and more effective than standard or clinical coumadin dosing (19 of 24 comparisons) but less costly and less effective than standard DOAC dosing (14 of 14 comparisons). The remaining comparisons were too few to observe any trend. Of 61 variables influential in changing base-case conclusions, effectiveness of PGx testing was the most common (37%), accounted for in the models using time-based or medication-based approaches or relative risk. The cost of PGx testing has decreased and plateaued over time.

CONCLUSIONS

EEs to date only partially inform decisions on selecting optimal PGx testing for AF, because most evidence focuses on PGx testing to determine coumadin dosing, but less on other purposes. Future EE may refer to the list of influential variables and the approaches used to account for the effect of PGx testing to inform data collection and study design.

Pharmacogenetic testing for adverse drug reaction prevention: systematic review of economic evaluations and the appraisal of quality matters for clinical practice and implementation

Background

Genetic testing has potential roles in identifying whether an individual would have risk of adverse drug reactions (ADRs) from a particular medicine. Robust cost-effectiveness results on genetic testing would be useful for clinical practice and policy decision-making on allocating resources effectively. This study aimed to update a systematic review on economic evaluations of pharmacogenetic testing to prevent ADRs and critically appraise the quality of reporting and sources of evidence for model input parameters.

Methods

We searched studies through Medline via PubMed, Scopus and CRD’s NHS Economic Evaluation up to October 2019. Studies investigating polymorphism-based pharmacogenetic testing, which guided drug therapies to prevent ADRs, using economic evaluation methods were included. Two reviewers independently performed data extraction and assessed the quality of reporting using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) guidelines and the quality of data sources using the hierarchy of evidence developed by Cooper et al.

Results

Fifty-nine economic evaluations of pharmacogenetic testing to avoid drug-induced ADRs were found between 2002 and 2018. Cost-utility and cost-effectiveness analyses were the most common methods of economic evaluation of pharmacogenetic testing. Most studies complied with the CHEERS checklist, except for single study-based economic evaluations which did not report uncertainty analysis (78%). There was a lack of high-quality evidence not only for estimating the clinical effectiveness of pharmacogenetic testing, but also baseline clinical data. About 14% of the studies obtained clinical effectiveness data of testing from a meta-analysis of case-control studies with direct comparison, which was not listed in the hierarchy of evidence used.

Conclusions

Our review suggested that future single study-based economic evaluations of pharmacogenetic testing should report uncertainty analysis, as this could significantly affect the robustness of economic evaluation results. A specific ranking system for the quality of evidence is needed for the economic evaluation of pharmacogenetic testing of ADRs. Differences in parameters, methods and outcomes across studies, as well as population-level and system-level differences, may lead to the difficulty of comparing cost-effectiveness results across countries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-07025-8.

Cost-effectiveness of precision medicine: a scoping review

Objectives

Precision medicine (PM) aims to improve patient outcomes by stratifying or individualizing diagnosis and treatment decisions. Previous reviews found inconclusive evidence as to the cost-effectiveness of PM. The purpose of this scoping review was to describe current research findings on the cost-effectiveness of PM and to identify characteristics of cost-effective interventions.

Methods

We searched PubMed with a combination of terms related to PM and economic evaluations and included studies published between 2014 and 2017.

Results

A total of 83 articles were included, of which two-thirds were published in Europe and the USA. The majority of studies concluded that the PM intervention was at least cost-effective compared to usual care. However, the willingness-to-pay thresholds varied widely. Key factors influencing cost-effectiveness included the prevalence of the genetic condition in the target population, costs of genetic testing and companion treatment and the probability of complications or mortality.

Conclusions

This review may help inform decisions about reimbursement, research and development of PM interventions.

Electronic supplementary material

The online version of this article (10.1007/s00038-019-01298-x) contains supplementary material, which is available to authorized users.

Systematic review of the evidence on the cost-effectiveness of pharmacogenomics-guided treatment for cardiovascular diseases

PURPOSE

To examine the evidence on the cost-effectiveness of implementing pharmacogenomics (PGx) in cardiovascular disease (CVD) care.

METHODS

We conducted a systematic review using multiple databases from inception to 2018. The titles and abstracts of cost-effectiveness studies on PGx-guided treatment in CVD care were screened, and full texts were extracted.

RESULTS

We screened 909 studies and included 46 to synthesize. Acute coronary syndrome and atrial fibrillation were the predominantly studied conditions (59%). Most studies (78%) examined warfarin-CYP2C9/VKORC1 or clopidogrel-CYP2C19. A payer's perspective was commonly used (39%) for cost calculations, and most studies (46%) were US-based. The majority (67%) of the studies found PGx testing to be cost-effective in CVD care, but cost-effectiveness varied across drugs and conditions. Two studies examined PGx panel testing, of which one examined pre-emptive testing strategies.

CONCLUSION

We found mixed evidence on the cost-effectiveness of PGx in CVD care. Supportive evidence exists for clopidogrel-CYP2C19 and warfarin-CYP2C9/VKORC1, but evidence is limited in other drug-gene combinations. Gaps persist, including unclear explanation of perspective and cost inputs, underreporting of study design elements critical to economic evaluations, and limited examination of PGx panel and pre-emptive testing for their cost-effectiveness. This review identifies the need for further research on economic evaluations of PGx implementation.

[Comparative clinical and economic evaluation of pharmacogenetic testing application for dabigatran in patients with atrial fibrillation]

AIM

To evaluate the clinical and economic feasibility of pharmacogenetic testing (PGT) for dabigataran etexilate administration in the treatment of atrial fibrillation (AF) without valve in comparison with tactics without pharmacogenetic testing.

MATERIALS AND METHODS

The pharmacoeconomic model was done using generalized data from published clinical, epidemiological and clinical - economic studies.

RESULTS AND DISCUSSION

Application of PGT on the carrier of allelic variant rs2244613 of CES1 gene for adjustment of dabigatrane etexilate dosage in patients with non - valve AF may be more cost - effective strategy for prevention of thromboembolic complications in patients with non - valve AF. Thus, due to the decrease in the number of undesirable drug reactions in the form of minor and major bleedings, the difference in treatment costs in the group with PGT compared to the group with standard pharmacotherapy tactics per 100 patients was 11 827.65 rubles. The expected cost per patient per year for standard treatment was 36 051.35 rubles, while in the group with PGT it was 35 933.07 rubles. The difference was 1182.76 rubles in favor of the pharmacogenetic approach Conclusion. A PGT approach to correct dabigatrane dosage can reduce the cost of pharmacotherapy by reducing the risk of adverse reactions of minor and major bleeding.

Genotype-guided warfarin therapy: current status

Warfarin pharmacogenomics has been an extensively studied field in the last decades as it is focused on personalized therapy to overcome the wide interpatient warfarin response variability and decrease the risk of side effects. In this expert review, besides briefly summarizing the current knowledge about warfarin pharmacogenetics, we also present an overview of recent studies that aimed to assess the efficacy, safety and economic issues related to genotype-based dosing algorithms used to guide warfarin therapy, including randomized and controlled clinical trials, meta-analyses and cost-effectiveness studies. To date, the findings still present disparities, mostly because of standard limitations. Thus, further studies should be encouraged to try to demonstrate the benefits of the application of warfarin pharmacogenomic dosing algorithms in clinical practice.

Cost Effectiveness of Genotype-Guided Warfarin Dosing in Patients with Mechanical Heart Valve Replacement Under the Fee-for-Service System

BACKGROUND

Although studies assessing the cost effectiveness of genotype-guided warfarin dosing for the management of atrial fibrillation, deep vein thrombosis, and pulmonary embolism have been reported, no publications have addressed genotype-guided warfarin therapy in mechanical heart valve replacement (MHVR) patients or genotype-guided warfarin therapy under the fee-for-service (FFS) insurance system.

OBJECTIVE

The aim of this study was to evaluate the cost effectiveness of genotype-guided warfarin dosing in patients with MHVR under the FFS system from the Korea healthcare sector perspective.

METHODS

A decision-analytic Markov model was developed to evaluate the cost effectiveness of genotype-guided warfarin dosing compared with standard dosing. Estimates of clinical adverse event rates and health state utilities were derived from the published literature. The outcome measure was the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY). One-way and probabilistic sensitivity analyses were performed to explore the range of plausible results.

RESULTS

In a base-case analysis, genotype-guided warfarin dosing was associated with marginally higher QALYs than standard warfarin dosing (6.088 vs. 6.083, respectively), at a slightly higher cost (US$6.8) (year 2016 values). The ICER was US$1356.2 per QALY gained. In probabilistic sensitivity analysis, there was an 82.7% probability that genotype-guided dosing was dominant compared with standard dosing, and a 99.8% probability that it was cost effective at a willingness-to-pay threshold of US$50,000 per QALY gained.

CONCLUSION

Compared with only standard warfarin therapy, genotype-guided warfarin dosing was cost effective in MHVR patients under the FFS insurance system.

Integrating genotypes in the SAMe-TT2R2 score for the prediction of anticoagulation control in Chinese patients with atrial fibrillation on warfarin

INTRODUCTION

The SAMe-TT₂R₂ score has been proposed to predict whether patients with atrial fibrillation (AF) would be well anti-coagulated with warfarin or not. However, it might over-estimate the number of patients under suboptimal warfarin treatment in non-Caucasians. This study was designed to modify the SAMe-TT₂R₂ score with genotypes and validate it in Chinese AF patients treated with warfarin.

MATERIAL AND METHODS

Consented Chinese-Han patients (n=510) with AF under the treatment of warfarin for at least 3months were randomly divided into a derivation (n=310) and a validation cohort (n=200). For each patient, CYP2C9*3 and VKORC1 -1639 A/G genotyping was performed, and the time in therapeutic range (TTR) was calculated over this period.

RESULTS

The modified SAMe-TT₂R₂ score was established by adding "warfarin genotype bins" to replace "the non-white race" variable. In the validation cohort, the discrimination performance of the modified score for good anticoagulation control (TTR≥70%) was significantly improved (c- index increased from 0.60 to 0.67). Significantly increased risks of major bleedings (HR: 4.91; 95% CI: 1.03-23.37; adjusted p=0.04) and all bleedings (HR: 1.93; 95% CI: 1.14-3.25; adjusted p=0.01) were found in patients with modified scores ≥2, as compared with patients with modified scores of 0-1.

CONCLUSIONS

The modified SAMe-TT₂R₂ score could improve the ability for the identification of good anticoagulation control, and the prediction of major bleeding events in Chinese patients with AF treated by warfarin.

Enabling Precision Cardiology Through Multiscale Biology and Systems Medicine

The traditional paradigm of cardiovascular disease research derives insight from large-scale, broadly inclusive clinical studies of well-characterized pathologies. These insights are then put into practice according to standardized clinical guidelines. However, stagnation in the development of new cardiovascular therapies and variability in therapeutic response implies that this paradigm is insufficient for reducing the cardiovascular disease burden. In this state-of-the-art review, we examine 3 interconnected ideas we put forth as key concepts for enabling a transition to precision cardiology: 1) precision characterization of cardiovascular disease with machine learning methods; 2) the application of network models of disease to embrace disease complexity; and 3) using insights from the previous 2 ideas to enable pharmacology and polypharmacology systems for more precise drug-to-patient matching and patient-disease stratification. We conclude by exploring the challenges of applying a precision approach to cardiology, which arise from a deficit of the required resources and infrastructure, and emerging evidence for the clinical effectiveness of this nascent approach.

The genetic basis of antiplatelet and anticoagulant therapy: A pharmacogenetic review of newer antiplatelets (clopidogrel, prasugrel and ticagrelor) and anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban)

INTRODUCTION

The study of pharmacogenomics presents the possibility of individualised optimisation of drug therapy tailored to each patients' unique physiological traits. Both antiplatelet and anticoagulant drugs play a key role in the management of cardiovascular disease. Despite their importance, there is a substantial volume of literature to suggest marked person-to-person variability in their effect. Areas covered: This article reviews the data available for the genetic cause for this inter-patient variability of antiplatelet and anticoagulant drugs. The genetic basis for traditional antiplatelets (i.e. aspirin) is compared with the newly available antiplatelet medicines (clopidogrel, prasugrel and ticagrelor). Similarly, the pharmacogenetics of warfarin is compared with the newer direct oral anticoagulants (DOACs) in detail. Expert Opinion: We identify strengths and weaknesses in the research thus far; including shortcomings in trial design and a review of newer analytical techniques. The direction of this research and its real-world implications are discussed.

Cost-effectiveness of pharmacogenetic-guided treatment: are we there yet?

Pharmacogenetics (PGx) has the potential to personalize pharmaceutical treatments. Many relevant gene-drug associations have been discovered, but PGx-guided treatment needs to be cost-effective as well as clinically beneficial to be incorporated into standard health-care. We reviewed economic evaluations for PGx associations listed in the US Food and Drug Administration (FDA) Table of Pharmacogenomic Biomarkers in Drug Labeling. We determined the proportion of evaluations that found PGx-guided treatment to be cost-effective or dominant over the alternative strategies, and estimated the impact on this proportion of removing the cost of genetic testing. Of the 137 PGx associations in the FDA table, 44 economic evaluations, relating to 10 drugs, were identified. Of these evaluations, 57% drew conclusions in favour of PGx testing, of which 30% were cost-effective and 27% were dominant (cost-saving). If genetic information was freely available, 75% of economic evaluations would support PGx-guided treatment, of which 25% would be cost-effective and 50% would be dominant. Thus, PGx-guided treatment can be a cost-effective and even a cost-saving strategy. Having genetic information readily available in the clinical health record is a realistic future prospect, and would make more genetic tests economically worthwhile.

Can pharmacogenetics help patients under chronic treatment with coumarin anticoagulants?

Vitamin K antagonists are highly effective antithrombotic drugs. However, appropriate dosing is difficult to establish owing to its narrow therapeutic window as well as widespread inter- and intra-individual variability in dosage. Compared with dosing solely based on clinical information, pharmacogenetics can help improve the therapy with coumarins by decreasing the time to reach a stable dose and reducing the risk of bleeding. Most of the studies about genotyping of patients using vitamin K antagonists have focused on predicting the stable dose. Two genes have been shown to have the most influence on dosing: VKORC1 and CYP2C9. Furthermore, genotyping of more genes, such as CYP4F2 and APOE, is also being included in some dosing algorithms. The role of genotype beyond the initial dose-titration phase is less clear. Thus, a proven genetically determined risk of unstable dose or bleeding could help with the selection of patients who require more frequent monitoring of dose. On the other hand, patients who have a genetically determined stable dose could self-monitor their international normalized ratio (INR), making the therapy less expensive and more convenient.

Economic evaluation of pharmacogenomic-guided warfarin treatment for elderly Croatian atrial fibrillation patients with ischemic stroke

BACKGROUND & METHODS

Economic evaluation in genomic medicine is an emerging discipline to assess the cost-effectiveness of genome-guided treatment. Here, we developed a pharmaco-economic model to assess whether pharmacogenomic (PGx)-guided warfarin treatment of elderly ischemic stroke patients with atrial fibrillation in Croatia is cost effective compared with non-PGx therapy. The time horizon of the model was set at 1 year.

RESULTS

Our primary analysis indicates that 97.07% (95% CI: 94.08-99.34%) of patients belonging to the PGx-guided group have not had any major complications, compared with the control group (89.12%; 95% CI: 84.00-93.87%, p < 0.05). The total cost per patient was estimated at €538.7 (95% CI: €526.3-551.2) for the PGx-guided group versus €219.7 (95% CI: €137.9-304.2) for the control group. In terms of quality-adjusted life-years (QALYs) gained, total QALYs was estimated at 0.954 (95% CI: 0.943-0.964) and 0.944 (95% CI: 0.931-0.956) for the PGx-guided and the control groups, respectively. The true difference in QALYs was estimated at 0.01 (95% CI: 0.005-0.015) in favor of the PGx-guided group. The incremental cost-effectiveness ratio of the PGx-guided versus the control groups was estimated at €31,225/QALY.

CONCLUSION

Overall, our data indicate that PGx-guided warfarin treatment may represent a cost-effective therapy option for the management of elderly patients with atrial fibrillation who developed ischemic stroke in Croatia.

Economic Evaluations of Pharmacogenetic and Pharmacogenomic Screening Tests: A Systematic Review. Second Update of the Literature

Objective

Due to extended application of pharmacogenetic and pharmacogenomic screening (PGx) tests it is important to assess whether they provide good value for money. This review provides an update of the literature.

Methods

A literature search was performed in PubMed and papers published between August 2010 and September 2014, investigating the cost-effectiveness of PGx screening tests, were included. Papers from 2000 until July 2010 were included via two previous systematic reviews. Studies’ overall quality was assessed with the Quality of Health Economic Studies (QHES) instrument.

Results

We found 38 studies, which combined with the previous 42 studies resulted in a total of 80 included studies. An average QHES score of 76 was found. Since 2010, more studies were funded by pharmaceutical companies. Most recent studies performed cost-utility analysis, univariate and probabilistic sensitivity analyses, and discussed limitations of their economic evaluations. Most studies indicated favorable cost-effectiveness. Majority of evaluations did not provide information regarding the intrinsic value of the PGx test. There were considerable differences in the costs for PGx testing. Reporting of the direction and magnitude of bias on the cost-effectiveness estimates as well as motivation for the chosen economic model and perspective were frequently missing.

Conclusions

Application of PGx tests was mostly found to be a cost-effective or cost-saving strategy. We found that only the minority of recent pharmacoeconomic evaluations assessed the intrinsic value of the PGx tests. There was an increase in the number of studies and in the reporting of quality associated characteristics. To improve future evaluations, scenario analysis including a broad range of PGx tests costs and equal costs of comparator drugs to assess the intrinsic value of the PGx tests, are recommended. In addition, robust clinical evidence regarding PGx tests’ efficacy remains of utmost importance.

New Oral Anticoagulants: How Do We Use Them Wisely?

The relative efficacy and safety of new oral anticoagulants (NOAC) have been consistent across a wide range of patients in clinical trials. On the one hand, they have offered new therapeutic options for stroke prevention in patients with atrial fibrillation (AF) and patients do like the experience of no need of frequent blood draws. On the other hand, their expensive prices, different formulary plans from different insurance companies, lack of antidote, and no method of monitoring the therapy are some of the challenges on their use in clinical practice. This narrative review aims to help clinicians understand these new oral anticoagulants better and choose them wisely according to their indications. In addition, other issues related to the use of NOAC, such as cost and methods of reversing their effects in hemorrhagic conditions, are also discussed.

Universal versus genotype-guided use of direct oral anticoagulants in atrial fibrillation patients: a decision analysis

AIM

This study aims to compare clinical and economic outcomes of CYP2C9 and VKORC1 genotype-guided (PG-DOAC) versus universal use of direct oral anticoagulant (DOAC) for stroke prevention in patients with atrial fibrillation (AF).

METHODS

Outcomes of oral anticoagulation therapy were simulated using life-long Markov modeling. In PG-DOAC, patients with genotype of high or low warfarin sensitivity were treated with DOAC, and patients with normal warfarin sensitivity genotype received warfarin.

RESULTS

Expected quality-adjusted life-years (QALYs) and cost of DOAC were higher than PG-DOAC. Incremental cost per QALY (ICER) of DOAC versus PG-DOAC was 314,129 USD/QALY, exceeding willingness-to-pay threshold (50,000 USD/QALY).

CONCLUSION

Using individual genotype to guide the use of DOAC versus warfarin appears to be the preferred strategy.

Clinical implications of neuropharmacogenetics

INTRODUCTION

Pharmacogenetics aims to identify the underlying genetic factors participating in the variability of drug response. Indeed, genetic variability at the DNA or RNA levels can directly or indirectly modify the pharmacokinetic or the pharmacodynamic parameters of a drug. The ultimate aim of pharmacogenetics is to move towards a personalised medicine by predicting responders and non-responders, adjusting the dose of the treatment, and identifying individuals at risk of adverse drug effects.

METHODS

A literature research was performed in which we reviewed all pharmacogenetic studies in neurological disorders including neurodegenerative diseases, multiple sclerosis, stroke and epilepsy.

RESULTS

Several pharmacogenetic studies have been performed in neurology, bringing insights into the inter-individual drug response variability and in the pathophysiology of neurological diseases. The principal implications of these studies for the management of patients in clinical practice are discussed.

CONCLUSION/DISCUSSION

Although several genetic factors have been identified in the modification of drug response in neurological disorders, most of them have a marginal predictive effect at the single gene level, suggesting mutagenic interactions as well as other factors related to drug interaction and disease subtypes. Most pharmacogenetic studies deserve further replication in independent populations and, ideally, in pharmacogenetic clinical trials to demonstrate their relevance in clinical practice.

Personalized antiplatelet and anticoagulation therapy: applications and significance of pharmacogenomics

In recent years, substantial effort has been made to better understand the influence of genetic factors on the efficacy and safety of numerous medications. These investigations suggest that the use of pharmacogenetic data to inform physician decision-making has great potential to enhance patient care by reducing on-treatment clinical events, adverse drug reactions, and health care-related costs. In fact, integration of such information into the clinical setting may be particularly applicable for antiplatelet and anticoagulation therapeutics, given the increasing body of evidence implicating genetic variation in variable drug response. In this review, we summarize currently available pharmacogenetic information for the most commonly used antiplatelet (ie, clopidogrel and aspirin) and anticoagulation (ie, warfarin) medications. Furthermore, we highlight the currently known role of genetic variability in response to next-generation antiplatelet (prasugrel and ticagrelor) and anticoagulant (dabigatran) agents. While compelling evidence suggests that genetic variants are important determinants of antiplatelet and anticoagulation therapy response, significant barriers to clinical implementation of pharmacogenetic testing exist and are described herein. In addition, we briefly discuss development of new diagnostic targets and therapeutic strategies as well as implications for enhanced patient care. In conclusion, pharmacogenetic testing can provide important information to assist clinicians with prescribing the most personalized and effective antiplatelet and anticoagulation therapy. However, several factors may limit its usefulness and should be considered.