Nothing will be the same in the post-covid world
16 March, 2021
Sleep sick: "I have never arrived awake from Actur to Puerto Venecia"
18 March, 2021
There are certain drugs called the fluoropyrimidine family that are administered in cancer treatment with great effectiveness, but there is a small number of patients who develop very serious toxicity to this type of chemotherapy.
This February, the Miguel Servet University Hospital began carrying out new pharmacogenetic studies in oncology patients – mainly colon cancer – to avoid toxicities before instituting treatment.
There are certain drugs called the fluoropyrimidine family that are administered in cancer treatment with great effectiveness, but there is a small number of patients who develop very serious toxicity to this type of chemotherapy and the genetic study allows us to know in advance this possible reaction to avoid it.
For the patient it is just another blood test, but what the specialists actually study are six specific polymorphisms of the so-called DPYD (dihydropyrimidine dehydrogenase) gene.
We all have this gene, but some people have polymorphisms that condition the activity of the enzyme that must help break down the drug, explains the Government of Aragon in a press release.
"If the enzyme does not work correctly, the drug is not metabolized properly and remains accumulated, which is toxic for the patient," explains Dr. Silvia Izquierdo, from the Genetics section of the Servet Clinical Biochemistry service.
If the gene presents any of these polymorphisms or a combination of them when administering a drug that uses this enzyme to eliminate itself, it can cause very serious toxicity to the patient.
The study determines if the activity of the enzyme is completely canceled, after which another treatment is administered, or if it is reduced by 75, 50 or 25%, indicates Dr. Izquierdo.
Subsequently, the pharmacists in the Oncology area analyze the detected polymorphisms and the patient's situation and, based on this data, establish recommendations on adjusting the appropriate and personalized dose of this treatment for each patient, points out Dr. Mª José Agustín, from the Service. of Pharmacy. Finally, the oncologist evaluates all the information from the Genetics Unit and the Pharmacy Service and makes the decision on the most appropriate treatment for each patient.
A small percentage of people (4 out of 100) have a reduced ability to metabolize this drug. And it is estimated that around 0,5-1% have the capacity of the enzyme completely nullified and may suffer fatal side effects when receiving normal doses of drugs from the fluoropyridine family.
Therapy with this type of drug is very effective and widespread, mainly to treat colon cancer and, to a lesser extent, for other types of cancer such as head and neck tumors, pancreas and some type of breast neoplasia.
For the implementation of these studies, the collaboration of the Pharmacy, Genetics (Clinical Biochemistry) and Oncology services of Servet has been necessary.
For Izquierdo, the genetic study to determine polymorphisms in the DPYD gene and its relationship with intolerance to fluoropyrimidines "is a great advance." “In the face of toxicity there is no going back and hence the importance of doing it prior to treatment and quickly,” he says.
