Pre‐emptive pharmacogenomics testing in clinical practice: A pilot implementation in Singapore

AIMS: Pre-emptive pharmacogenomics (PPGx) testing holds promise for optimizing drug therapy, but uptake remains limited in Asia. This pilot study aimed to assess the feasibility of PPGx uptake into clinical practice and its impact on prescribing in an Asian healthcare setting. METHODS: A prospective, multicentre pilot study was conducted to pre-emptively genotype 16 pharmacogenes. Results were integrated into electronic health records, alongside deployment of clinical decision support (CDS) tools for 31 drug-gene pairs. A pharmacogenomics drug information service and digital platforms were also developed. RESULTS: All 2492 participants carried ≥1 actionable variant (median: 5, range: 1-11). Across four institutions within one cluster, 1046 out of 2238 (46.7%) patients were prescribed ≥1 drug with pharmacogenetic association, and of those, 460 (44%) had genotypes linked to undesirable drug responses. Among 285 interruptive CDS alerts, 69 (24.2%) led to prescription modifications. Acceptance was higher for new prescriptions (50.0% vs. 17.3%, p < 0.001), in outpatient settings (31.0% vs. 7.3%, p < 0.001) and among consultants (57.1% vs. other designations 5-27.3%, p < 0.001). The drug information service received 137 enquiries, while 471 and 151 patients accessed the app and web-based platforms respectively. CONCLUSIONS: PPGx testing and genotype-guided prescribing are feasible in Singapore. Widespread adoption requires leadership support, robust informatics infrastructure, clinician engagement and sustainable funding.