Attitudes toward pharmacogenetics in patients undergoing CYP2C19 testing following percutaneous coronary intervention.

Aim: Patient knowledge and attitudes toward pharmacogenetic (PGx) testing may impact adoption of clinical testing. Methods: Questionnaires regarding knowledge, attitudes and ethics of PGx testing were distributed to 504 patients enrolled in the ADAPT study conducted at two urban hospitals in Philadelphia, Pennsylvania, USA. Responses were assessed using multivariable logistic regression. Results: 311 completed the survey (62% response rate). 74% were unaware of PGx testing, but 79% indicated using PGx results to predict medication efficacy was important. In a multivariable model, higher education level (p = 0.031) and greater genetics knowledge (p < 0.001) were associated with more positive attitudes toward PGx testing. Conclusion: Greater patient knowledge of genetics was associated with a more positive attitude toward PGx testing, indicating that educational strategies aimed at increasing genetics knowledge may enhance adoption of PGx testing in the clinic.

Pharmacogenetic (PGx) testing looks for genetic variations that may impact one's ability to respond to certain medications. This has the potential to improve patient care and minimize side effects from medications but is not currently used as standard of care for several reasons including a limited understanding of patient perceptions toward PGx testing. This study aimed to assess patient knowledge, attitudes and ethics of PGx testing. Questionnaires were given to patients enrolled in a clinical trial at two urban hospitals in Philadelphia, Pennsylvania, USA. In the study, patients underwent a nonsurgical procedure to open narrowed blood vessels supplying the heart muscles and were prescribed antiplatelet medications afterward. As part of study participation, some patients had undergone PGx testing to guide antiplatelet therapy following while others received standard of care (no PGx testing). We found that patients were generally not aware of PGx testing but felt it would be important information to have to guide their treatment options. Higher education levels and greater genetics knowledge were factors associated with more positive attitudes toward PGx testing. An understanding of patient perceptions, knowledge and misconceptions of PGx testing can allow healthcare professionals to better address knowledge gaps and increase the use of PGx testing in clinical settings.

Prospective CYP2C19 Genotyping to Guide Antiplatelet Therapy Following Percutaneous Coronary Intervention: A Pragmatic Randomized Clinical Trial.

BACKGROUND: CYP2C19 loss-of-function alleles impair clopidogrel effectiveness after percutaneous coronary intervention, but the clinical impact of implementing CYP2C19 genotyping in a real-world setting is unknown. The purpose of the study was to determine whether returning CYP2C19 genotype results along with genotype-guided pharmacotherapy recommendations using a rapid turnaround test would change antiplatelet prescribing following percutaneous coronary intervention.The primary outcome was the rate of prasugrel or ticagrelor prescribing in each arm. Secondary outcomes included agreement to the genotype-guided recommendations. METHODS: At the time of percutaneous coronary intervention, participants were randomly assigned to prospective rapid point-of-care genotyping of CYP2C19 major alleles (*2, *3, *17) via salivary swab (genotyped group) or no genotyping (usual care) to guide antiplatelet drug selection. Interventional cardiologists at 2 cardiac catheterization laboratories within the same health system were provided genotype information along with genotype-guided pharmacotherapy recommendations. RESULTS: A total of 504 participants were randomized, 249 to the genotyped and 255 to the usual care group. The participants were primarily men (73%); age, 63±10 years; and 50% had acute coronary syndromes. In the genotyped group, 28% were carriers of loss-of-function alleles (*2, *3). The use of prasugrel or ticagrelor was significantly higher in the genotyped group compared with the usual care group (30% versus 21%; odds ratio, 1.60 [95% CI, 1.07-2.42]; P=0.03). Within the genotyped group, 53% of loss-of-function allele carriers were started on prasugrel/ticagrelor, while 47% were started on clopidogrel. CONCLUSIONS: In a randomized controlled trial of clinical CYP2C19 genotyping implementation, pharmacogenetic test results significantly influenced antiplatelet drug prescribing; however, almost half of CYP2C19 loss-of-function carriers continued to receive clopidogrel. Interventional cardiologists consider both clinical and genetic factors when selecting antiplatelet therapy following percutaneous coronary intervention. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT02508116.