• English
  • Suomi

Genetic testing improves medication safety and effectiveness

Professor Mikko Niemi, a pharmacogenetics expert at the University of Helsinki, studies the impact of genes on the effectiveness and safety of medications. In a recently published study, the medications of 1.4 million Finnish patients were analysed, revealing that a quarter of patients received medications whose efficacy or safety could have been improved by considering the patient’s genome.  The study used data from registries of the Finnish Institute for Health and Welfare (THL) and biobank data.

 

People react to medications differently – some experience insufficient effectiveness, while others may have adverse effects. The reason for varying responses may be our physical characteristics, other medication, or genome. If doctors had access to information about patients’ genetics, medication costs and significant adverse effects could often be reduced, and the number of days of sick leave would also decrease.

In the past five years, genetic testing in healthcare has increased.

“There’s now a wealth of research evidence. The key genes influencing drug response have likely been identified. Many of them regulate the amount of a drug in the body. Often, one gene affects many different types of medications,” Niemi says.

Pharmacogenetic panel tests contain 10-20 genes associated with drug metabolism, drug effects, or the risk of adverse effects. They are particularly useful in the treatment of cancers, psychiatric disorders, and cardiovascular diseases. Using CYP genes, cytochrome P450 enzymes are produced, which play a crucial role in the metabolism of many drugs and endogenous compounds (e.g., steroids and fatty acids). These genes are highly significant in drug metabolism and influence how individuals respond to medications. Genetic differences can play a decisive role in the success of drug treatments. Examples of CYP enzymes: CYP3A4: One of the most common enzymes responsible for drug metabolism. Among other things, it metabolises statins, benzodiazepines and HIV medications, accounting for up to half of drug metabolism. CYP2C9: Metabolises non-steroidal anti-inflammatory drugs (such as ibuprofen) and the anticoagulant warfarin. CYP2D6: Involved in the metabolism of many psychiatric medications and opioids. CYP2C19: Affects clopidogrel (an antiplatelet medication). Influences the blood concentrations of certain antidepressants, which can impact both their efficacy and the occurrence of adverse effects.

A gene panel can be used to predict the suitability of a medication

 

In recent years, various gene panels have been developed to analyse multiple genes simultaneously. This can be considered a breakthrough in healthcare. DNA is extracted from the patient’s blood, saliva or tissue. Massive parallel sequencing allows for the targeted study of many genes at once. The panels can be designed to identify genetic variations that may affect, for example, disease risk, drug response or the occurrence of certain hereditary diseases.

Progress in the use of pharmacogenetic laboratory tests occurred in 2020 with the involvement of the European Medicines Agency (EMA).

“At that time, the agency issued a recommendation to test for hereditary DPYD deficiency before initiating fluoropyrimidine-based cancer treatment. This helps prevent serious adverse effects caused by these anticancer drugs. Testing has been a routine since the agency’s recommendation.”

Pharmacogenetic panels typically test between 10 and 20 genes.

“Humans have 20,000 genes. We know well the effects of 10 to 20 genes on drug treatment. These are key to drug response,” says Niemi.

Helsinki University Hospital’s (HUS) pharmacogenetic gene panel covers the 12 most common and clinically significant genes affecting drug treatments. The selection of these genes took into account international guidelines, drug summaries and the prevalence of genetic variations in different populations. Test results are available in Finnish under the title B -PGx-D, in the MyKanta personal health information online service (https://www.kanta.fi/en/mykanta) MyKanta is an online, publicly accessible service where people can access prescriptions, laboratory test results and healthcare records.

“The idea of the panel is that when the suitability of one medication is tested, the patient also has all other relevant genetic factors for many future medications already tested.”

According to Niemi, with the improvement of testing, more drugs are now known to be influenced by genetics. As a result, drug treatment for cancer, for example, has improved. The use of genetic information in psychiatry has also become more common.

”We are starting to have solid research evidence on the benefits of pharmacogenetics in the treatment of depression.  Genetic testing has been included in the Current Care Guidelines for the treatment of depression.”

The Current Care Guidelines (Käypä hoito) are expert summaries published by the Finnish Medical Society Duodecim on the diagnosis and effectiveness of treatments for specific diseases.

 

Genetic information could improve the medication for every one in four

 

The required dosage of individual medications can vary dramatically between individuals, sometimes by more than tenfold. This may depend on how quickly or slowly the body eliminates the medication. Cytochrome enzymes (CYP) play a key role in breaking down and eliminating drugs from the body. There is considerable genetic variation in the activity of CYP enzymes, which can lead to vastly different drug concentrations and responses in individuals.

Cytochrome P450 enzymes catalyse chemical reactions that modify drugs to be more easily eliminated from the body. Drugs can inhibit or activate these enzymes, affecting the metabolism of other medications taken simultaneously. This can lead to either an enhancement or reduction in the effect of the medication, as well as potential adverse effects. The activity of cytochrome P450 enzymes varies genetically, which affects how efficiently individuals metabolise drugs.

Currently, there is limited knowledge about how beneficial and cost-effective pharmacogenetic tests would be if the genetic background of all hospital patients were known. Niemi’s research conducted a nationwide analysis that included all internal medicine and surgical patients in Finnish hospitals, as well as a group of university hospital patients for whom genetic data was available from the THL biobank.  The biobank contains the FINRISKI data, which holds an exceptionally large amount of diverse health data about the Finnish population, including laboratory tests and health registry data.

The nationwide cohort included data from 1.4 million people in Finland obtained from THL-managed registries. Two years after hospitalisation, 60 per cent of patients had purchased a prescription medication for which genetic information is relevant.

“We tracked purchases of medications where we knew genetics influences drug suitability. By analysing genetic variations, we now know for sure that 99 per cent of people in Finland have a clinically significant genetic variant affecting the response to at least one medication.”

The university hospital sample included 1,000 patients, whose genetic information was available from the biobank. Forty per cent of these patients received medications during their hospital stay for which genetic testing could be beneficial. A quarter of them had a gene-drug combination that researchers do not recommend: the medication should be used at a different dosage, or it would be better to choose an entirely different medication.

“Genetic variation is common and affects widely used medications.”

According to Niemi, genetic information could be highly beneficial in drug treatment.

“Based on current research, many patients could benefit from adjusting their medication based on genetic information.”

The benefits are also significant for society. Finland has excellent registry and genomic data management, and is a leader in the use of pharmacogenetic panels.

“In the future, the aim is to assess the economic and health benefits of pharmacogenetic panel testing. The goal is to examine the treatment costs of Finnish patients who have undergone pharmacogenetic testing and compare this to a situation where genetic testing has not been used. For example, if it were possible to identify the ten percent of patients who benefit the most from genetic information, it could lead to savings in healthcare costs, medications, and sick leave.”

Niemi’s research group has used the computing services of Finland’s ELIXIR Node at CSC – IT Center for Science to analyse genetic data. Data management has made use of CSC’s sensitive data platform.

The Genomic Data Infrastructure (GDI) launched in 2022 aims to create a federated infrastructure for researchers which enables an access to European genomic and clinical data. In the future, Europeans will have faster and more accurate diagnoses. Collected and analysed genomic data will enable better drug design and preventive treatments.

Niemi sees it as essential that researchers have access to such infrastructure.

“High-quality genomic data storage is crucial for future research. It ensures that new genetic factors influencing drug efficacy and safety can be identified and their impact can be assessed, and that they can ultimately be put into use.”

GDI will enable retrospective research, including cost benefit analysis on European scale cohorts, as described by Niemi.

“By linking genetic information to disease and treatment information, GDI helps researchers to discover cohorts with specific treatments and genetic variants across Europe, increasing the size of these cohorts and hence supporting the discovery novel genetic effects on medication”, says senior coordinator Dylan Spalding from CSC. Spalding is the co-lead of GDI Work Package 5.

“For clinicians who have a patient who is not responding to medication as expected, GDI will also enable them to find other clinicians across Europe who may have similar patients with different and more effective treatment regimes, and hence improve the treatment of these patients.”

 

Ari Turunen

6.2.2025

Read article in PDF