HealthDecember 17, 2018

Pharmacogenomics: Preemptive testing decisions reach across the care team


From a research and academic perspective, we often tout the potential value of pharmacogenomics (PGx), the study of the genetic variations that contribute to the wide variability in drug responses in patients. But implementing PGx testing in actual practice, and determining how it fits into the workflow of various care teams, remains something of a puzzle.

Preemptive pharmacogenomics testing is still emerging as best practice, translating genotypes into actionable phenotypes. Even in cases where preemptive testing is conducted, sharing the information isn’t always efficient. In the future, this will be more easily integrated into the electronic medical record (EMR), making the results accessible and available at the time a physician is prescribing a medication.

Academic centers are currently implementing preemptive PGx testing, possibly providing the framework for other care settings, including modeling small, integrated networks for health information exchange. In addition, there are projects funded by the Food and Drug Administration (FDA), Centers for Medicaid and Medicare Services (CMS), and National Institutes of Health (NIH) aimed at increasing the awareness and implementation of PGx testing.

Nonetheless, adoption of preemptive testing has been slow in professional care settings. A variety of healthcare providers and teams could potentially be involved in the ordering, execution, and use of preemptive PGx testing, but not all segments of healthcare are integrating the practice at the same pace and with an eye on information sharing.

Current practices: Physicians

PGx testing hinges upon the physician’s order. A survey of 285 physicians from 5 IGNITE sites reported that the majority believe genetic testing is clinically useful, but only a third believe they had obtained adequate training to manage genetically “high-risk” patients. The survey also revealed:

  • Most physicians felt unprepared to use genetic information in their practice and believe steps need to be taken to develop tools and training for physicians
  • Physicians with 5 years or fewer in practice were more likely to report that their training had prepared them to care for genetically high-risk patients than those with over 5 years’ experience (41% vs 25%)

Some specialists are, perhaps, better positioned to integrate pharmacogenomics into their practice. Oncologists, for example, are more likely to be interested in pharmacogenomics testing than other practitioners overall.

Another recently published study revealed physician reluctance toward participation in research and clinical implementation of pharmacogenomics programs due to a limited evidence base. This is not necessarily unusual with an emerging discipline. There tends to be a lack of communication between investigators and clinicians, and clinical and leadership engagement on new research can be slow to gain momentum.

When physicians do order preemptive PGx testing, it tends to be when prescribing newer drugs. Even in cases where the disposition of older drugs may be affected by a patient’s genetic factors, clinicians may feel they understand how to manage adverse drug events with these older, more familiar medications, and a PGx test may not seem like it will help inform their clinical care decisions.

A multidisciplinary genetics team

The most effective way to deploy pharmacogenomics testing may be through a community-based medical genetics program, employing a multidisciplinary team composed of the following providers:

  • Medical geneticist
  • Pharmacist
  • Nurse practitioner
  • Genetic counselor

Genetic counselors often do not have pharmacy training. Therefore, a partnership between genetic counselors and pharmacists can be valuable in assisting clinicians and facilitating the application of PGx test results. Genetic counselors – with their genetic training, risk communication, and counseling background – can pair well with pharmacists, who contribute knowledge of pharmacokinetics and pharmacodynamics, to better communicate and advise potential alterations to treatment plans.

In a U.S. survey of genetic counselors, 52% of respondents said they believe genetic counseling to be a necessary component of PGx testing.

Beyond simply convening a collaborating care team, a genetics program would require five key elements to be successful:

  • Billable-service provider
  • Process for documentation of relevant medication and family histories
  • Personnel with the knowledge required to interpret PGx results
  • Personnel to discuss risks, benefits, and limitation of testing
  • Mechanism for reporting results

The role of labs

Labs that conduct PGx tests often provide FAQs and other guides to help clinicians better understand why they might want to order PGx testing. Sometimes the information and direct marketing done by labs may actually compound practice challenges clinicians face.

Many clinicians are not sufficiently trained in possible interpretations of the pharmacogenetic tests, so simply being persuaded to order them may cause more confusion than benefit. In addition, clinicians face the challenge of external data coming in from the direct-to-consumer genetic testing that is now available, increasing the patient’s access to their own genetic information, and thus the questions they may have.

The most helpful background a lab could provide is not only clinical and cost-effectiveness information, but also guidance on clinical utility. A clinician needs to understand the usefulness, benefits, and disadvantages of PGx testing within their daily clinical practice.

Changes needed in EMRs

Currently, integrating genomic data and clinical decision support tools into electronic health records is one of the largest barriers clinicians face to adopting preemptive pharmacogenomics testing.

The inconsistent quality and completeness of the data in the EMR presents multiple challenges, including:

  • Defining phenotype cohorts (regarding exposure and outcomes)
  • Accounting for the patient’s adherence to their medications

Although this is one large barrier, the Electronic Medical Records and Genomics network is leading the way in piloting and implementing PGx and integrating the results within the EMR and clinical decision support systems. A survey of 10 of the sites within the network reported that delays in the process were not stemming from the pharmacogenomics testing itself, but more likely to be related to health information technology and challenges with staffing levels and communication.

The insurance question

Although dependent upon the patient’s insurance coverage, many have been successful in obtaining reimbursement for PGx tests, most notably for single gene-drug pair tests.

Per an analysis of beneficiaries:

  • Single-gene tests are most often billed to Medicare
  • Between 2012 and 2013, 519,340 tests were billed for the genes CYP2D6, CYP2C19 and CYP2C9
  • Total expenditures for just these 3 genes were $117,845,531 among 454,575 beneficiaries
  • This was equal to approximately $260 per individual test

Most preemptive testing does not fit the majority of payers’ model for genetic testing coverage decisions. One large barrier is the current practice of traditional reimbursement decisions based on medical necessity. Payers stress the importance of the FDA approving and including PGx testing on a product label.

A project called The RIGHT project (Rational Integration of Genomic Healthcare Testing) may address this gap by estimating average clinical efficacy and cost-effectiveness of preemptive PGx testing across diverse patient populations

Ultimately, pursuing genetic testing and background becomes the responsibility of all parties involved on the care team. Direct-to-consumer testing is growing, allowing patients increased access to information, but this also increases the need for clinicians and healthcare professionals to understand and enhance their own knowledge surrounding PGx testing and its utility.

Kandace Schuft, PharmD, is Senior Clinical Content Specialist - Pharmacogenomics with Clinical Effectiveness at Wolters Kluwer, Health, working collaboratively within the drug information team to contribute to core pharmacology content for both referential and embedded offerings. She earned her Doctor of Pharmacy and Bachelor of Arts degrees from the University of Minnesota and completed a post-graduate pharmacy practice residency and pharmacogenomics certification program.

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