Configuring an implementation model for multi-drug pharmacogenomic testing in the NHS

Youssef, Essra (2022) Configuring an implementation model for multi-drug pharmacogenomic testing in the NHS. Doctoral thesis, University of East Anglia.

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Pharmacogenomic testing can improve patient outcomes through safer and more efficient dose and drug selection. Implementation of multi-drug pharmacogenomic testing in clinical care has been fragmented internationally and is largely absent within the NHS. The aim of this thesis was to develop and refine a programme theory using behaviour science for the implementation of multi-drug pharmacogenomic testing within an NHS context.

Underpinned by behavioural science, the research programme comprised three empirical studies. The first study modelled the impact of multi-drug pharmacogenomic testing in UK primary care, by estimating the occurrence of actionable drug gene interactions in daily practice, using first prescription volumes for 56 PGx drugs and phenotype frequency data. The second study involved a systematic review and narrative synthesis of the barriers and enablers to implementing multi-drug pharmacogenomic testing, using the TDF to map factors affecting prescriber, pharmacist, and patient behaviours. Finally, the third study was a qualitative exploration of the real-world implementation of multi-drug pharmacogenomic testing in the NHS, conducted using a case study methodology.

Over 20% of all new prescriptions annually issued for 56 medicines in UK primary care had an actionable drug-gene interaction according to guidelines from the Dutch Pharmacogenetic Working Group and/or the Clinical Pharmacogenetics Implementation Consortium. A multi-drug pharmacogenomic testing programme which constitutes testing genetic variants in four genes (CYP2C19, CYP2D6, SLCO1B1, HLA-B) would cover more than 95% of the potential drug-gene interactions occurring in UK primary care.

The systematic review found barriers to the implementation of multi-drug pharmacogenomic testing can be organised around four themes influencing behaviours of prescribers, pharmacists and patients. These are: IT infrastructure, Effort, Rewards and Unknown Territory. Barriers were most consistently mapped to TDF domains: memory, attention and decision-making processes, environmental context and resources, and belief about consequences. Pharmacists played a vital role in PGx testing implementation model and enabled prescribers to order and deliver PGx testing for patients.

Empirical data using a case study methodology of real-world implementation of multi-drug pharmacogenomic testing, found pharmacists were key drivers for PGx testing implementation model within an NHS context. Training to prepare health professionals to deliver and utilise PGx testing in clinical decision making, should focus on skills development and managing expectations of both patients and health professionals of what PGx testing can provide.

These three studies advance the understanding of implementing multi-drug pharmacogenomic testing by converging implementation science and genomic medicine. The modelling study provides researchers and policy makers with new knowledge to design a minimum drug-gene panel for a PGx testing panel relevant to the UK population. The multi-drug PGx testing implementation configuration informed by the systematic review and case study requires further modelling and feasibility testing to optimise before implementation across NHS settings.

Keywords: pharmacogenomics, personalised medicine, implementation

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Pharmacy
Depositing User: Chris White
Date Deposited: 21 Jun 2023 14:06
Last Modified: 21 Jun 2023 14:06


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