Pharmacogenomics: Key to personalized drugs
What is Pharmacogenomics?
Pharmacogenomics is the study of how an individual's genetic inheritance affects the body's response to drugs. The term comes from the words ‘pharmacology’ and ‘genomic’ and is thus the intersection of pharmaceuticals and genetics.
Pharmacogenomics holds the promise that drugs might one day be tailor-made for individuals and adapted to each person's own genetic makeup. Environment, diet, age, lifestyle, and state of health all can influence a person's response to medicines, but understanding an individual's genetic makeup is thought to be the key to creating personalized drugs with greater efficacy and safety.
Pharmacogenomics combines traditional pharmaceutical sciences such as biochemistry with annotated knowledge of genes, proteins, and single nucleotide polymorphisms. It is a science that examines the inherited variations in genes that dictate drug response and explores the ways these variations can be used to predict whether a patient will have a good response to a drug, a bad response to a drug, or no response at all.
Benefits of Pharmacogenomics
Pharmacogenomics will eventually provide tailored drug therapy based on genetically determined variation in effectiveness and side effects. This will mean:
- More powerful medicines: Pharmaceutical companies will be able to produce therapies more targeted to specific diseases, maximizing therapeutic effects while decreasing damage to nearby healthy cells.
- Better, safer drugs the first time: Recovery time will go down and safety will go up as the likelihood of adverse drug reactions goes down or is eliminated altogether.
- More accurate methods of determining appropriate drug dosages: Current methods of basing dosages on weight and age will be replaced with dosages based on a person's genetics --how well the body processes the medicine and the time it takes to metabolize it.
- Decrease in the overall cost of health care: Decreases in the number of adverse drug reactions, the number of failed drug trials, the effects of a disease on the body (through early detection), and the number of medications patients must take to find an effective therapy will promote a net decrease in the cost of health care.
- Advanced screening for disease: Knowing one's genetic code will allow a person to make adequate lifestyle and environmental changes at an early age so as to avoid or lessen the severity of a genetic disease. Likewise, advance knowledge of a particular disease susceptibility will allow careful monitoring, and treatments can be introduced at the most appropriate stage to maximize their therapy.
- Better vaccines: Vaccines made of genetic material, either DNA or RNA, promise all the benefits of existing vaccines without all the risks. They will activate the immune system but will be unable to cause infections. They will be inexpensive, stable, easy to store, and capable of being engineered to carry several strains of a pathogen at once.
- Improvements in the drug discovery and approval process: Pharmaceutical companies will be able to discover potential therapies more easily using genome targets. Previously failed drug candidates may be revived as they are matched with the niche population they serve. The drug approval process should be facilitated as trials are targeted for specific genetic population groups --providing greater degrees of success. Targeting only those persons capable of responding to a drug will reduce the cost and risk of clinical trials.
Changing the future of healthcare
Although pharmacogenomics has the potential to radically change the way health care is provided, it is only in its infancy. In the future, pharmacogenomics could find uses along the entire drug discovery and development timeline, all the way from target discovery and validation to late-stage clinical trials.
Beyond that, pharmacogenomic tests could find their way into the doctor's office as a means to get the right medicine to the right patient at the right time. Some people believe that pharmacogenomics will lead to the stratification of diseases into genetically defined categories.
Pharmacogenomics can be used in many ways during drug discovery and development. For example, it can identify variations in drug targets and ensure that companies are screening against the most common variant. However, pharmacogenomics is most likely to be used during the clinical development process.
Pharmacogenomics will probably be most successful in areas such as oncology, where many therapies are available but each one works for only a small percentage of patients. Getting the treatment right the first time can be important, even life saving.
It is hoped that by the year 2030, the diagnosis of the patient illness as well as the therapy to be prescribed would be made by genomic testing using the DNA chip rather than by clinical symptoms alone. Discoveries of gene variations, affecting how the drugs work in breast cancer, asthma, hypertension, diabetes point to just a few of the diseases in which pharmacogenomics will have a big impact. Once the researchers have pinpointed the genes and the associated variations responsible for these diseases, therapies for each would quickly follow.
Time to take Pharmagenomics seriously
In order for pharmacogenomics to advance, people must start treating it as a serious field that is a part of genetics. Technology must also advance if the field is to move forward. A platform that can do large amounts of genotyping inexpensively is required.
In addition to technological improvements, gaps in the knowledge of the human genome need to be filled. There are still big gaps in terms of mapping genes onto the chromosomes.
P harmacogenomics is really an outgrowth of the human genome project, which has opened up the genetic world to the pharmacy world and has resulted in the development of drugs on the basis of genes exclusively.
Pharmaceutical and biotech companies will have to form partnerships with diagnostics companies so that pharmacogenomics is available at some reasonable price and some reasonable time frame so it can be not just a scientific breakthrough but a commercial success.
In order for pharmacogenomics to take hold, pharmaceutical companies, physicians, and patients are going to have to understand how it will benefit them. The field of Pharmacogenomics has the potential to revolutionize the way we practice medicine. We now have the ability to better treat patients with the most effective medications at the correct doses.
It is surprising to know that all humans are 99.9% genetically identical. The 0.01 per cent difference in genome sequences accounts for difference in our susceptibility to, or protection from all kinds of diseases, the age of onset and severity of illness and the way our body responds to different classes of drugs. Major drugs companies worldwide, joined by young band of pharmacogenomics companies are hunting assiduously for these small variations in the human genes that explain why drugs work well for some but not for others. The understanding of genetic variations will positively impact all aspects of medicines in the coming years.
B arriers to Pharmacogenomics progress
Pharmacogenomics is a developing research field that is still in its infancy. Several of the following barriers will have to be overcome before many pharmacogenomics benefits can be realized.
- Our limited knowledge of which genes are involved with each drug response. Since many genes are likely to influence responses, obtaining the big picture on the impact of gene variations is highly time-consuming and complicated.
- Only one or two approved drugs may be available for treatment of a particular condition. If patients have gene variations that prevent them using these drugs, they may be left without any alternatives for treatment.
- Most pharmaceutical companies have been successful with their "one size fits all" approach to drug development. Since it costs hundreds of millions of dollars to bring a drug to market, these companies will be reluctant to develop alternative drugs that serve only a small portion of the population.
- Introducing multiple pharmacogenomic products to treat the same condition for different population subsets undoubtedly will complicate the process of prescribing and dispensing drugs. Physicians must execute an extra diagnostic step to determine which drug is best suited to each patient. To interpret the diagnostic accurately and recommend the best course of treatment for each patient, all prescribing physicians, regardless of specialty, will need a better understanding of genetics.
Human genetics has a great job potential in India and abroad. A large number of students in this field are getting a good response from foreign countries in the research as well as the job sector. Students have a good opportunity to work in the area of pharmacogenomics in the pharmaceutical industry, besides having good career options in genetic testing laboratories, which is a relatively new concept in India, and studies the career status of diseased genes in different genetic disorders. There is also a chance to work in genetic counseling to the couples and families suffering from genetic diseases.
There are good prospects in clinical laboratories in the field of molecular diagnostics for various genetic disorders and infectious diseases and in reproductive genetics, where help is offered to infertile couples and those afflicted with genetic problems through prenatal genetic analyses.
Forensic genetics have opened up new vistas for human geneticists, who by molecular genotyping can provide valuable insights into genetic individualization of criminals, thus helping in solving crime.
Courses and institutions
Pharmacogenomics is offered as a specialization option in postgraduate and doctorate courses in a number of reputed educational institutions. Graduates in the field of science and forensic science are eligible doing a pharmacogenomics course. The course duration ranges from a few months to one year. Some institutes offering pharmacogenomics courses are
- Bioinformatics Institute of India, Hyderabad
- Institute of Genomics and Integrative Biology, New Delhi
- Institute of Bioinformatics and Applied Biotechnology, Bangalore
- Madurai Kamaraj University, Madurai
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