Personalized Medicines: The Targeted Disease Therapy Approach

Personalized medicine is a technology-based highly specific and precise approach to prediction, prevention, diagnosis and treatment of diseases. It tries to defy the generalization of the medicines by averaging the trials in a large population, but advocates on medicines based on the specific needs of patients, against a specific disease.

“If it were not for the great variability among individuals, medicine might as well be a science and not an art.” - Sir William Osler

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The concept of personalized medicine co-existed since the dawn of the medicinal era, but gained more focus after the genomic analysis and its relation to the disease was established. Out of the 3 billion base pairs in the human DNA which is a big mess; the variation or diversity among the human population is responsible only by 3 million bases (99.9 % all human DNA is identical). But still, the diversity of human beings (phenotypic and genotypic) and the susceptibility and response to a certain disease and drugs is substantially huge. As a result, no single medication can benefit precisely the bulk of human variants which is the ultimate baseline for conceiving the idea of the personalizing medicines.




The terms Personalized medicine, Precision medicine, P4 medicine, and stratified medicine is used interchangeably, but the concept has raised a common misconception. Personalized medicine is often misunderstood as the medicinal plan or health concerned decisions of a single person, patient, or individual. However, Personalized medicine aims to gather the information on the genetic basis of disease common to a group of individuals; dividing them into subpopulations or strata who respond similarly to certain diseases and medicines. 

With this approach, treatments can be directed to only a subpopulation who are benefitted from the specified medicinal therapy, while others can be omitted for alternate therapy keeping them from the effects and consequences of the medicine. The concept is similar to the narrow spectrum antibiotics — antibiotics selective for a specific organism or bacterial genera, which targets distinct cell constituent or transcribed product to kill the microorganism. This keeps intact the normal flora, or beneficial microorganisms from being wiped out from the body unnecessarily.

Principally, personalized medicines rely on the genetic makeup of an individual. About 25,000 genes in the human body are responsible for the production of metabolites and biochemicals which carry out the essentials of the entire living system. Metabolomics (the study of all of the metabolites in an organism), coupled with Pharmacogenetics (the study of the role of the genome in drug response) and Transciptiomics (the study of RNA molecules and their functions in one cell) integrate with the development of personalized medicines.



In the course, the identification of biomarkers (DNA sequences associated with certain pathological or physiological process or disease) is an important step. Modern Technology, gene sequencing, and bioinformatics tools drives the allocation and precise examination of these biomarkers and also enables easy biological target identification for medicines and drugs. Facilitating the identification of biomarkers is whole-exome sequencing (the sequencing of coding regions), microarrays (protein expression analysis) and biochemical tests. Genetic profiles and bioinformatics data (from sequencing) can be invariably utilized to also analyze genetic variations, gene variants, genetic anomalies, mutants, and metabolome.

The information acquired by the sequencing techniques coupled with the Rational drug designing approach (the inventive process of finding new medications based on the knowledge of a biological target. Wikipedia) animate the drug discovery process in an immaculate pattern. When it comes personalizing these drugs, the gene sequences of the diseased individual is statistically analyzed with those of the normal or suspected ones, to predict the likeliness for the onset of the particular disease or diagnose if the patient falls within the subpopulation. If susceptible or matched, the strategy for prevention and treatment of the disease can be effectively implemented. With every individual in the subgroup, sharing the similar patterns of DNA or defective genes, the susceptibility or the likelihood of the disease can be determined. In the case of high susceptibility, preventive measures can be applied. Drug therapies can also be employed to intervene any silently progressing disease to avoid potential complications in the future.

Source: The Personalized Medicine Report 2017

Personalized Medicinal approach marks key potential benefits like low side effects, optimum dosage, decreased chances of allergies and high effectiveness. Other advantages are Predictive Testing (to detect gene mutations associated with disorders that appear after birth, often later in life), and the intervening ability to interfere with the progression of disease its pre-stage. Some of the other merits are enlisted.

Source: The Personalized Medicine Report 2017

P4 Medicines has proved efficient in the treatment of cancer with a range of drugs already approved by the FDA. The applications of personalized medicines in Neurology, Psychiatry, Cardiovascular diseases, and other chronic illness are also evidence of potential benefits. Multiple avenues in the treatment of several clinical issues and genetic disorders are under consideration with higher potentials and promises; such as in the treatment of Alzheimer’s disease, Parkinson’s disease, Multiple Sclerosis, and other various neurological conditions.

Source: The Personalized Medicine Report 2017

The underlying statistical data reveals the percentage of patients by types of cancer whose tumors could be targets for specific Personalized Medicines.

About 21 drug therapies have been approved by the FDA in the treatment of multiple types of cancer. Some of the medicines (Bevacizumab) are used in the treatment of multiple types of cancers.

A few of them, along with their biomarkers are enlisted below.

Herceptin (trastuzumab) — medication for 30% of breast cancers associated with an overexpression of HER-2 protein

Gleevec (Imatinib mesylate) — in treatment of chronic myeloid leukemia

Zelboraf (Vemurafenib) — used to treat melanoma (drug benefits those with the V600E defect in the DNA)

Erbitux (Cetuximab) — colon cancer associated with EFGR

Xalkori (crizotinib) — lung cancer associated with ALK. (Gordon E. The state of personalized medicine: the role of biomarkers. Presented at the Personalized Medicine World Congress; January 23, 2012; Stanford University, Stanford, CA.)

Atezolizumab (Tecentriq) — for Bladder cancer associated with CD274

Darzalex (daratumumab)- Multiple myelomas associated with CD38

Sprycel (dasatinib) — Leukemia associated with BCR-ABL

Bevacizumab (Avastin) — Brain cancer, cervical cancer, colorectal cancer, kidney cancer, lung cancer, ovarian epithelial cancer, fallopian tube cancer and primary peritoneal cancer associated with VEGF

Personalized Medicine at a glance is an emerging, precise and technologically advanced medicinal practice with futuristic approaches and applications in cancer treatment, neurological disorders, genetic abnormalities and an array of chronic illness so as to lower the potential risks of disease as well as medicines to susceptible individuals and patients.

References and Sources:

Di Sanzo, M., Cipolloni, L., Borro, M., La Russa, R., Santurro, A., Scopetti, M., … & Frati, P. (2017). Clinical applications of personalized medicine: a new paradigm and challenge. Current pharmaceutical biotechnology, 18(3), 194–203.

(Cutter, G. R., & Liu, Y. (2012). Personalized medicine: The return of the house call?. Neurology: Clinical Practice, 2(4), 343–351.)

Personalized Medicine Coalition — THE PERSONALIZED MEDICINE REPORT 2017