Population-based medicines have greatly benefited humanity in general. However, every individual reacts differently to the same medication due to factors such as genetic makeup and environmental stressors. In the pursuit of achieving optimal clinical and therapeutic outcome, the pharmaceutical industry has been putting in enormous efforts to cater to individual needs of a patient.
Personalized medicines are customized, tailor-made therapies administered to patients who do not respond to conventional medications or therapies. This therapeutic approach makes use of a patient’s genetic and epigenetic data. Genetic profiling of an individual helps health care professionals make better clinical judgments with respect to the type of drugs or treatment to be administered.
Role of Pharmacogenomics and Pharmacogenetics in Personalized Medicines
Pharmacogenomics is a therapeutic field that helps in identifying the genes that affect drug response in a patient. These studies also uncover data on genes that are responsible for susceptibility to a particular disease. Pharmacogenomics can help in speeding up the process of treating a disease. For instance, the genetic variations present in a breast cancer patient can be identified by a simple blood test, thereby allowing for selection of the right drug, dosing concentration and frequency of dosing. Pharmacogenetic testing is commercially used for cancer medications and medications for blood coagulation.
By applying pharmacogenetics and pharmacogenomics, the variable drug responses in each patient are linked to the patient’s genetic profile. With this data, personalized medicines are being developed for the management of infectious diseases, cancer, bladder dysfunction, gynecological disorders, neurological disorders, as well as autoimmune diseases.
Of late, blood transcriptomics and metabolomics are also being used to develop personalized medicines due to their fine accuracy and analytical capability. Both these fields use the general principle of OMICS and can provide a better understanding of the human biological state. In metabolomics, high-resolution mass spectrometry is used that can detect more than 10,000 metabolites with unparalleled precision. Blood transcriptomics aids in understanding the systemic immune response by detecting changes in the cell populations and immune pathways. Data obtained from these fields can be used to build robust models that provide details on the disease mechanism and risk factors associated with the disease.
Pharmacogenomics: The Right Drug, for the Right Patient, at the Right Dose
The Theranostic Approach
Theranostics or pharmacodiagnostics is a branch of medicine that effectively combines molecular diagnostic tests with specified targeted therapy. This field also plays a vital role in providing personalized medicine. For example, in nuclear medicine, the theranostic approach involves coupling of diagnostic imaging and therapy using the same or similar molecules that are administered in different doses or are radiolabeled differently.
This approach can already predict if the intervention would be beneficial or not to the patient, which is a bonus in case of children or in immunocompromised individuals. In addition, theranostics can help in estimating the safety and toxicity of targeted nuclear therapies. Studies have demonstrated that patients with neuroendocrine tumors showed no evidence of grade 3 or grade 4 toxicity, even after more than 8 cycles of radiopeptide therapy.
Pros and Cons of Personalized Medicines
The pharmaceutical industry views the production of personalized medicines as a medical arena with its own benefits and challenges. By molecularly selecting specific patient populations, the timelines for drug development can be shortened by conducting robust and smaller phase 3 clinical trials. However, there are also a number of challenges in developing personalized medicines.
Firstly, the selection of an exclusive patient population increases the initial costs of drug discovery and development due to the complexity of many analytic and diagnostic procedures involved. Secondly, it is a challenge to find and target the correct intermediate molecule causing the disease.
Ethical issues have been raised in the past, as many government and university bodies are yet to come up with strict standards for the diagnosis of genetic disorders/diseases before prescribing personalized medicines. Incorrect laboratory testing can render the personalized medicine ineffective or toxic as unnecessary administration may lead to toxicity and other serious adverse events.
In the era of genomic and molecular medicine, the development of personalized medicine not only involves the scientists, academia, and industry players but also the patients. Patient satisfaction comes with effective disease management and improved quality of life. To build patient trust and treatment compliance, vital information on the treatment strategy should be shared with them.
Although conventional medicine continues to hold a prominent place in treatment and disease management, personalized medicines do show a promising future in providing “right treatment to the right patient at the right time”.
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