AIMS: To systematically review the current state of PGx in the primary care settings and determine the enablers and challenges of its implementation.

DESIGN: A scoping review was carried out by adhering to Arksey and O'Malley's 6-stage methodological framework and the 2020 Joanna Briggs Institute and Levac et al. DATA SOURCES: Cochrane Library, EMBASE, Global Health, MEDLINE and PubMed were searched up to 17 July 2023.

ELIGIBILITY CRITERIA: All peer-reviewed studies in English, reporting the enablers and the challenges of implementing PGx in the primary care settings were included.

DATE EXTRACTION AND SYNTHESIS: Two independent reviewers extracted the data. Information was synthesised based on the reported enablers and the challenges of implementing PGx testing in the primary care settings. Information was then presented to stakeholders for their inputs.

RESULTS: 78 studies discussing the implementation of PGx testing are included, of which 57% were published between 2019 and 2023. 68% of the studies discussed PGx testing in the primary care setting as a disease-specific themes. Healthcare professionals were the major stakeholders, with primary care physicians (55%) being the most represented. Enablers encompassed various advantages such as diagnostic and therapeutic benefits, cost reduction and the empowerment of healthcare professionals. Challenges included the absence of sufficient scientific evidence, insufficient training for healthcare professionals, ethical and legal aspects of PGx data, low patient awareness and acceptance and the high costs linked to PGx testing.

METHODS: We systematically searched for original research in PubMed, Cochrane Central Register of Controlled Studies, CINAHL Plus, EMBASE and HuGE Navigator from database inception until January 2018. Studies on association between polymorphism and antineoplastic-induced cardiovascular toxicity in patients treated for cancer of all antineoplastic agents were included except for anthracycline. Case reports, conference abstracts, reviews and non-patient studies were excluded. Data extracted by two independent reviewers were combined with random-effects model and reported according to PRISMA and MOOSE guidelines.

RESULTS: The 35 studies included examined a total of 219 SNPs in 80 genes, 11 antineoplastic and 5 types of cardiovascular toxicities. Meta-analyses showed that human epidermal growth factor receptor 2 (HER2) rs1136201, a risk variants (pooled OR: 2.43; 1.17-5.06, p = 0.018) is a potential predictors for trastuzumab-related cardiotoxicity. Gene dose effect analysis showed number of variant allele may contribute to the risk too.

METHODS: Genomic DNA obtained from a 55 years old, self-declared healthy, anonymous male of Malay descent was sequenced. The subject's mother died of lung cancer and the father had a history of schizophrenia and deceased at the age of 65 years old. A systematic, intuitive computational workflow/pipeline integrating custom algorithm in tandem with large datasets of variant annotations and gene functions for genetic variations with pharmacogenomics impact was developed. A comprehensive pathway map of drug transport, metabolism and action was used as a template to map non-synonymous variations with potential functional consequences.

PRINCIPAL FINDINGS: Over 3 million known variations and 100,898 novel variations in the Malay genome were identified. Further in-depth pharmacogenetics analysis revealed a total of 607 unique variants in 563 proteins, with the eventual identification of 4 drug transport genes, 2 drug metabolizing enzyme genes and 33 target genes harboring deleterious SNVs involved in pharmacological pathways, which could have a potential role in clinical settings.