Personalized medicine is about customizing the disease treatment as per the individual. It is a field of healthcare that takes into consideration an individual’s unique clinical information, environmental information, and most importantly, genetics. Because these factors are different for every person, the nature of disease (its onset, course, etc) and the individual’s response to drugs or interventions is unique too. Identifying genetic and clinical information allows accurate predictions to be made about a person's susceptibility of developing disease, the course of disease, and his/her response to treatment.
Healthcare providers and their patients have been now looking forward to utilizing personalized medicine effectively by translating the genomic findings into precise diagnostic tests and targeted therapies. Some areas have even been pretty successfully using this information for advancing not just research, but also clinical decision-making.
Below we talk about some important therapies formulated on the basis of molecular analysis in order to place patients into more individualized treatment groups:
Breast Cancer: Breast cancer has been found to exhibit extensive variability at the molecular level, so much that at least five tumor subtypes can be identified by patterns of gene expression. This molecular heterogeneity may cause clinical outcomes of the disease to vary widely among women. Many cases of hereditary breast cancer can be attributed to mutations in the BRCA1 and BRCA2 genes. This serves as a valuable confirmation that certain types of breast cancers could be clinically managed differently from the rest. Since then, targeted therapies have been developed in order to treat other subsets of breast cancer (e.g., tamoxifen and trastuzumab). HER2 protein is overexpressed in about 30% of patients with breast cancer and is not responsive to standard therapy. So personalized therapeutic approaches become necessary.
Melanoma: B-Raf protein is involved in sending signals for cell growth. The gene responsible for its production (BRAF) undergoes mutation in cancers. Vemurafenib, an approved drug for the treatment of late-stage melanoma, is a B-Raf protein inhibitor. Many personalized therapies are present today in the field of pharmacogenomics and cancer therapeutics, however, relatively few such approaches exist for chronic cardiovascular, lung and metabolic diseases that are among the top ten killers in the world as per WHO. The majority of therapeutics work on a one-size-fits-all approach, owing to the heterogeneous clinical manifestations of these complex disorders that make them difficult to manage through personalized medicine.
Cardiovascular Disease: Endomyocardial biopsy or heart biopsy is an invasive technique that was practiced prior to the development of gene expression profiling test to identify heart transplant recipients’ probability of rejecting a transplanted organ. The good news is that a non-invasive diagnostic blood test has now replaced it. This genetic testing, since it predicts rejection risk, is useful in guiding precise and tailored immunosuppressive drug regimes, and hence, a longer-term approach of patient management.
Alzheimer's Disease: Treatment of Alzheimer’s has been a frustrating journey so far for both doctors and patients. Till date, the efforts have been directed towards slowing down the symptoms, by targeting beta-amyloid protein in the brain. However, there is now a shift in thought as the evidence point towards a critical fact that beta-amyloid is necessary for the disease but not sufficient to cause the disease.
Most of the rethinking was prompted by the constantly failing clinical trials, driving researchers to re-examine their hypotheses of disease mechanism. Another reason for the apparent failure of large clinical trials to identify effective treatments may be the faulty assumption that Alzheimer ‘s disease is a single clinical entity. A complete risk profile of a patient with Alzheimer disease reveals vast variation in risk markers that may serve to guide treatment. Associating diseases that require different treatment strategies may obscure small responsive subgroups.
Although there is still a long way to go for personalized medicine to get established in the field of Alzheimer’s, the good part is the continued elucidation of novel genes involved in the disease and their genetic profiling ( including whole-genome sequencing, whole-exome sequencing, transcriptome profiling, as well as genomic/epigenomic and proteomic characterization) can help formulate a personalized approach for its prediction and prevention.
