A feasibility study on <bold>im</bold>plementing pre-emptive <bold>p</bold>harmacogenomics <bold>t</bold>esting in outpatient clinics in Singapore (IMPT study)

In view of the limited data related to preemptive pharmacogenomics (PGx) testing in the primary care setting, we designed a study to assess the feasibility of implementing preemptive PGx services at outpatient clinics, with the aim to assess the practicality and challenges of implementing preemptive PGx testing within primary care, and its impact on clinical workflows and patient care. This prospective study was conducted between October 2022 and August 2023 at five outpatient clinics located in Singapore. Patients aged 21 to 65 with a reported history or risk of developing any of the target chronic conditions or any patients receiving one of the 29 PGx-associated medications were recruited. Patients' buccal samples were processed using a multi-gene qPCR-based panel of 21 allele variants of five pharmacogenes. Surveys were administered to study participants and clinicians to assess their perceptions and outcomes related to PGx testing. Among the 222 patients, 95% had at least one clinically actionable variant. Of these patients, 113 reported taking at least one of the 29 studied drugs, with 21.2% of them receiving at least one clinically actionable recommendation based on their PGx results. A total of 150 patients (67.6%) participated in the post-test follow-up survey. Among them, 70% expressed feeling relieved and happy upon receiving their test reports and reported increased confidence in taking their prescribed medication. Furthermore, clinicians identified the necessity for clearer legal regulations regarding PGx testing and insurance coverage to enhance future adoption of PGx testing. Given a high prevalence of clinically actionable variants in almost all tested patients, this study underscores the feasibility and clinical benefits of preemptive PGx testing in primary care clinics in Singapore.Clinical Trial Registration: This study is registered with ClinicalTrials.gov, identifier NCT05504135, with the registration date of August 17, 2022.