1. Better Selection of Drugs

The ability of pharmacogenomics to inform drug selection is among its most important contributions. Clinicians can determine which treatments are most likely to work for a given patient by discovering genetic markers linked to drug response.

For example, the enzyme CYP2D6 must be activated for tamoxifen, a typical hormonal treatment for estrogen receptor-positive (ER+) breast cancer, to work. Tamoxifen metabolism can be poor or intermediate due to genetic variations in the CYP2D6 gene, which can result in less than ideal therapy outcomes. Patients with these variations can be found via pharmacogenomic testing, which enables doctors to think about alternate treatments like aromatase inhibitors for better outcomes.

2. Improving Medication Dosage

The connection between medication metabolism and genetic differences extends to dose determination. While underdosing can decrease efficacy, overdosing can increase toxicity. For instance, many cancer medications are metabolized by the enzyme CYP3A4, and genetic changes in the CYP3A4 gene can affect how the drug acts in the body. By checking for these differences, doctors can modify dosages to strike a balance between safety and effectiveness.

3. Mitigating Side Effects and Toxicity

Many chemotherapy drugs, including doxorubicin and fluorouracil, have serious side effects. Predisposition to these negative consequences can be predicted by genetic markers. For example, significant fluorouracil toxicity is associated with mutations in the DPYD gene, which codes for the enzyme dihydropyrimidine dehydrogenase. Individuals with specific DPYD variations have impaired medication metabolism, which could lead to life-threatening side effects. Pharmacogenomic testing enables early identification of these patients, allowing for dose adjustments or alternative treatments to be explored.

Similarly, genetic differences in genes like RARG can affect the risk of cardiotoxicity linked to anthracyclines like doxorubicin. Finding these indicators aids oncologists in balancing the advantages and disadvantages of utilizing these medications and in thinking about preventative measures or alternate therapies.

4. Improving the Results of Targeted Therapy

Treatment for HER2-positive breast cancer has been transformed by targeted treatments such as trastuzumab and pertuzumab. But not every patient reacts to these treatments in the same way. A patient’s likelihood of benefiting from these treatments can be determined in part by genetic testing for HER2 amplification and mutations in genes like PIK3CA.

The identification of resistance mechanisms is another use of pharmacogenomics. For instance, resistance to aromatase inhibitors may result from mutations in the ESR1 gene, which may influence the selection of alternative treatments.