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One in ten patients (9.8%) had a genetic variation that warranted a “red flag” warning to switch treatment of a prescribed medicine, a national pharmacogenomics pilot in England has found.
In addition, one in four patients overall had a medicine change as a result of the testing, as part of the NHS England PROGRESS pilot scheme for pharmacogenomic guided prescribing in primary care.
The PROGRESS trial began in June 2023, initially across ten practices in north-west England, then expanding across England in February 2025.
Vicky Chaplin, senior clinical lead for the genomics unit at NHS England, told the British Oncology Pharmacy Association annual conference, held in London on 2 October 2026, that the PROGRESS scheme involved more than 1,325 patients in total who were started on a new medicine — the majority being prescribed a statin or a selective serotonin reuptake inhibitor (SSRI).
After a genetic test, 91% of participants in the pilot were found to have a “clinically relevant” variation in one of the four key study genes (CYP2C19, CYP2D6, SLCO1B1, CYP2C9).
Three in ten patients (30.5%) received an “orange flag” recommendation that advised a potential dose or titration switch.
This guidance was acted upon by 90% of healthcare professionals, resulting in a medication change for one in four study participants.
Chaplin told delegates that ongoing training for clinicians in genomics would need to be “built in” in the future, “because this area is going to keep advancing and we are going to all have to keep on top of it, so we can deliver the best care to our patients”.
Chaplin also said that expanding the genomics medicine service to a genomic population health service would require “access to genomic testing… In much broader parts of the healthcare system so that patients can access that care… closer to home as part of routine services”.
“The prediction is [that] by 2035, up to 50% of healthcare decisions will involve a genomic result of some sort,” she told delegates.
She suggested that genomic testing must be built into prescribing decisions “so it becomes a routine part of medicines optimisation, like checking a patient’s renal function.
“This is why we really do need everyone involved in research, because particularly in an area like genomics, where we’re seeing all these innovations and the pace that we’re going at, we can’t have research over here, and then clinical practice over here, we are running side by side so that we can get this out to patients as quickly and as safely as possible.”
Chaplin also shared information on NHS England’s genomic test directory. Tests might be developed in response to medicine licences, National Institute of health and Care Excellence recommendations, or new developments in genomic medicine, she said.
A digital version of the national test directory should be available from April 2027, she added, while work was ongoing to digitise the ordering of tests.
“We need a big infrastructure in place in order to deliver this safely and effectively for our patients,” Chaplin said.
