PROJECT SUMMARY Preemptive pharmacogenetic (PGx) testing may be particularly beneficial in medically underserved populations by reducing the number of appointments required to optimize drug therapy and increasing the effectiveness of less expensive off-patent medications – the type most often with pharmacogenetic guidelines available (PGx drugs). However, there is little data available to guide clinical implementation in these patient populations. Our long-term goal is to contribute toward the efficient implementation of PGx into clinical practice to improve the precision of medication prescribing. The overall objective for this application is to identify PGx drug usage patterns in medically underserved patients, and assess the feasibility and effectiveness of preemptive PGx testing in this patient population. The central hypothesis is that medically underserved patients are prescribed more PGx drugs, and preemptive PGx testing is feasible as well as effective in improving patient medication satisfaction. The rationale for the proposed research is that identifying patient populations that can most benefit from PGx testing will facilitate clinical implementation that may reduce medication treatment disparities. We plan to test the central hypothesis and accomplish the overall objective of this application by pursuing three specific aims. The first aim is to identify clinical, demographic and socioeconomic factors associated with PGx drug prescribing patterns in a large, real-world, diverse patient population. We will accomplish this aim by comparing clinical, demographic, and socioeconomic data with prescription data from millions of patients across the State of Florida. The second aim is to develop a low-cost, ancestrally inclusive PGx testing panel designed to inform commonly used PGx drugs. We will design a low-cost, clinically validated panel that will include variants common in racial minorities in the U.S. We plan to leverage extensive batching of tests and an already available genotyping platform that minimizes labor costs in order to achieve significant cost savings. The third aim is to determine the feasibility of low-cost preemptive PGx testing in a medically underserved population as well as its effect on patient medication satisfaction. We will accomplish this aim by completing a randomized open-label clinical trial comparing medically underserved patients receiving preemptive PGx testing to those receiving usual care. We will compare key implementation metrics and will also conduct semi-structured interviews in both patients and healthcare providers to assess PGx perceptions of feasibility and sustainability from stakeholders. The proposed research is significant because it should contribute valuable preliminary data toward both the real-world effectiveness of preemptive PGx testing as well as the feasibility of studying and implementing this technology in medically underserved patients – an area of PGx research where few data are ...