A major new clinical trial in Scotland is set to explore how a simple genetic test could transform prescribing practices by tailoring medication to individual patients—enhancing treatment efficacy and reducing harmful side effects.
The PHOENIX Study, one of the largest of its kind globally, aims to recruit up to 4,000 patients over two years across NHS Greater Glasgow and Clyde. Led by Professor Sandosh Padmanabhan, Chair of Pharmacogenomics at the University of Glasgow, the study will assess how genetic differences influence response to 60 commonly prescribed medications in the NHS.
The trial is being conducted at the Queen Elizabeth University Hospital (QEUH) in Glasgow, in partnership with the University of Glasgow Living Laboratory, West of Scotland Innovation Hub, and industry collaborators myDNA and Agena Bioscience.
Eligible in-patients at QEUH who are newly prescribed one or more of the selected medications will be invited to participate. With their consent, patients will undergo a non-invasive genetic test, and results—delivered within days—will help clinicians determine the most suitable drug and dosage based on the patient's DNA.
Studies show that around 15% of patients carry genetic variants that can impact how drugs are metabolized—leading to reduced efficacy or increased risk of side effects. Without pharmacogenomic (PGx) testing, clinicians often rely on trial-and-error prescribing, which can prolong treatment and elevate risk.
Participants in the PHOENIX trial will be randomly assigned to receive either immediate PGx testing or delayed testing after three months. This will allow researchers to assess the real-world clinical and economic impact of pharmacogenomic-informed prescribing versus standard care. Patients will be monitored for side effects, treatment outcomes, and medication changes throughout the trial.
Professor Padmanabhan stated: “This study will evaluate whether PGx-guided treatment can significantly reduce adverse drug reactions and improve effectiveness. Our goal is to generate strong clinical and health-economic evidence to inform future NHS policy.”
Dr Katriona Brooksbank, Innovation Lead at NHSGGC, added: “This trial puts precision medicine into practice, helping us understand how a patient’s genetic makeup can shape safer, more effective treatments.”
One of the first participants, Eric Balish, joined the study after experiencing a heart attack. Having been prescribed clopidogrel—one of the drugs under review—Eric shared, “It feels good to contribute to something that could improve care for others.”
Industry partner Gene by Gene, whose CAP-, CLIA-, and AABB-accredited labs provide testing for the study, says the trial marks a major step toward routine precision medicine. If successful, the PHOENIX Study could lead to broader adoption of genetic testing in everyday prescribing across Scotland and beyond.