On pharmacogenomics in pharmacy benefit management

Strategies and settings of clinical pharmacogenetic implementation: a scoping review of pharmacogenetics programs

Pharmacogenetic (PGx) literature has shown beneficial outcomes in safety, efficacy and cost when evidence-based gene-drug decision making is incorporated into clinical practice. PGx programs with successfully implemented clinical services have been published in a variety of settings including academic health centers and community practice. The primary objective was to systematically scope the literature to characterize the current trends, extent, range and nature of clinical PGx programs. Forty articles representing 19 clinical PGx programs were included in analysis. Most programs are in urban, academic institutions. Education, governance and workflow were commonly described while billing/reimbursement and consent were not. This review provides an overview of current PGx models that can be used as a reference for institutions beginning the implementation process.

Pharmacogenomic Variants and Drug Interactions Identified Through the Genetic Analysis of Clozapine Metabolism

OBJECTIVE

Clozapine is the only effective medication for treatment-resistant schizophrenia, but its worldwide use is still limited because of its complex titration protocols. While the discovery of pharmacogenomic variants of clozapine metabolism may improve clinical management, no robust findings have yet been reported. This study is the first to adopt the framework of genome-wide association studies (GWASs) to discover genetic markers of clozapine plasma concentrations in a large sample of patients with treatment-resistant schizophrenia.

METHODS

The authors used mixed-model regression to combine data from multiple assays of clozapine metabolite plasma concentrations from a clozapine monitoring service and carried out a genome-wide analysis of clozapine, norclozapine, and their ratio on 10,353 assays from 2,989 individuals. These analyses were adjusted for demographic factors known to influence clozapine metabolism, although it was not possible to adjust for all potential mediators given the available data. GWAS results were used to pinpoint specific enzymes and metabolic pathways and compounds that might interact with clozapine pharmacokinetics.

RESULTS

The authors identified four distinct genome-wide significant loci that harbor common variants affecting the metabolism of clozapine or its metabolites. Detailed examination pointed to coding and regulatory variants at several CYP* and UGT* genes as well as corroborative evidence for interactions between the metabolism of clozapine, coffee, and tobacco. Individual effects of single single-nucleotide polymorphisms (SNPs) fine-mapped from these loci were large, such as the minor allele of rs2472297, which was associated with a reduction in clozapine concentrations roughly equivalent to a decrease of 50 mg/day in clozapine dosage. On their own, these single SNPs explained from 1.15% to 9.48% of the variance in the plasma concentration data.

CONCLUSIONS

Common genetic variants with large effects on clozapine metabolism exist and can be found via genome-wide approaches. Their identification opens the way for clinical studies assessing the use of pharmacogenomics in the clinical management of patients with treatment-resistant schizophrenia.

Integrating pharmacogenetic testing into primary care

Introduction

Pharmacogenetic (PGx) testing has greatly expanded due to enhanced understanding of the role of genes in drug response and advances in DNA-based testing technology development. As many primary care visits result in a prescription, the use of PGx testing may be particularly beneficial in this setting. However, integration of PGx testing may be limited as no uniform approach to delivery of tests has been established and providers are ill-prepared to integrate PGx testing into routine care.

Areas covered

In this paper, the readiness of primary care practitioners are reviewed as well as strategies to address these barriers based on published research and ongoing activities on education and implementation of PGx testing.

Expert Commentary

Widespread integration of PGx testing will warrant continued education and point-of-care decisional support. Primary care providers may also benefit from consultation services or team-based care with laboratory medicine specialists, pharmacists, and genetic counselors.

The role of hospital pharmacists in the adoption and use of pharmacogenomics and precision medicine

Aim: Our aim was to assess the knowledge and attitudes of US hospital pharmacists about the implementation of clinical pharmacogenomics, and examine liability risks of adopting pharmacogenomics by pharmacists. Methods: We surveyed hospital pharmacists. Linear regression models of predictor variables for pharmacist adoption and use of pharmacogenomics were analyzed. Results: The survey was administered to 660 hospital pharmacists (23% response rate; n = 149). The majority of respondents (72%) favor implementing pharmacogenomics into pharmacy practice. However, only 25% are confident in their abilities to interpret pharmacogenomic test results. Conclusion: Pharmacists lack confidence in their abilities to interpret and use pharmacogenomic information in clinical care. These results raise potential liability risks that are pertinent to pharmacists.

Pilot study of pharmacist-assisted delivery of pharmacogenetic testing in a primary care setting

AIM

To describe the rationale and design of a pilot program to implement and evaluate pharmacogenetic (PGx) testing in a primary care setting.

STUDY RATIONALE

Several factors have impeded the uptake of PGx testing, including lack of provider knowledge and challenges with operationalizing PGx testing in a clinical practice setting.

STUDY DESIGN

We plan to compare two strategies for the implementation of PGx testing: a pharmacist-initiated testing arm compared with a physician-initiated PGx testing arm. Providers in both groups will be required to attend an introduction to PGx seminar. Anticipated results: We anticipate that providers in the pharmacist-initiated group will be more likely to order PGx testing than providers in the physician-initiated group.

CONCLUSION

Overall, we aim to generate data that will inform an effective delivery model for PGx testing and to facilitate a seamless integration of PGx testing in primary care practices.

Pharmacogenomic knowledge gaps and educational resource needs among physicians in selected specialties

BACKGROUND

The use of pharmacogenomic testing in the clinical setting has the potential to improve the safety and effectiveness of drug therapy, yet studies have revealed that physicians lack knowledge about the topic of pharmacogenomics, and are not prepared to implement it in the clinical setting. This study further explores the pharmacogenomic knowledge deficit and educational resource needs among physicians.

MATERIALS AND METHODS

Surveys of primary care physicians, cardiologists, and psychiatrists were conducted.

RESULTS

Few physicians reported familiarity with the topic of pharmacogenomics, but more reported confidence in their knowledge about the influence of genetics on drug therapy. Only a small minority had undergone formal training in pharmacogenomics, and a majority reported being unsure what type of pharmacogenomic tests were appropriate to order for the clinical situation. Respondents indicated that an ideal pharmacogenomic educational resource should be electronic and include such components as how to interpret pharmacogenomic test results, recommendations for prescribing, population subgroups most likely to be affected, and contact information for laboratories offering pharmacogenomic testing.

CONCLUSION

Physicians continue to demonstrate pharmacogenomic knowledge gaps, and are unsure about how to use pharmacogenomic testing in clinical practice. Educational resources that are clinically oriented and easily accessible are preferred by physicians, and may best support appropriate clinical implementation of pharmacogenomics.

Clinical delivery of pharmacogenetic testing services: a proposed partnership between genetic counselors and pharmacists

One of the basic questions in the early uses of pharmacogenetic (PGx) testing revolves around the clinical delivery of testing. Because multiple health professionals may play a role in the delivery of PGx testing, various clinical delivery models have begun to be studied. We propose that a partnership between genetic counselors and pharmacists can assist clinicians in the delivery of comprehensive PGx services. Based on their expert knowledge of pharmacokinetics and pharmacodynamics, pharmacists can facilitate the appropriate application of PGx test results to adjust medication use as warranted and act as a liaison to the healthcare team recommending changes in medication based on test results and patient input. Genetic counselors are well-trained in genetics as well as risk communication and counseling methodology, but have limited knowledge of pharmaceuticals. The complementary knowledge and skill set supports the partnership between genetic counselors and pharmacists to provide effective PGx testing services.

Clinical decision support for personalized medicine: an opportunity for pharmacist-physician collaboration

Pharmacogenomics has significant potential to improve the efficacy and safety of medication therapy, but it requires new expertise and adds a new layer of complexity for all healthcare professionals. Pharmacists and pharmacy management systems can play a leading role in providing clinical decision support for the use and interpretation of pharmacogenomic tests. To serve this role effectively, pharmacists will need to expand their expertise in the emerging field of clinical pharmacogenomics. Pharmacy-based clinical programs can expedite the use of pharmacogenomic testing, help physicians interpret the test results and identify future medication risks associated with the patient's phenotype. Over time, some of these functions can be embedded in clinical decision support systems as part of the broader automation of the healthcare system.