Using living organisms and related molecules, biotechnology helps to make novel medicines, personal therapies and diagnostics for diagnosing diseases. Although there has been wide acceptance in using biotechnology in making medicinal products, there has been some resistance as well.
Today, specialized medicines of biotech origin for a plethora of diseases like heart attack, multiple sclerosis and cystic fibrosis have sort of become pervasive in our daily lives. This article is about breakthrough biotech cures in some disease segments, the role played by genetics in helping to administer drugs, and how pharmacogenomics is gaining importance.
What is the difference between a medicine of biotech origin and a conventional medicine?
When the body is besieged by disease, aberrant proteins are made by the human body as well as by infection causing agents that are the primary cause of the disease. Conventional drugs block the activity of these proteins, and that's how they work.
But drugs of biotech origin work differently. As an example, consider biotech drugs that use RNA interference technology that involves switching off genes or more specifically that works by silencing the activity of a particular gene. Now genes are made of DNA which makes messenger RNA and it is m RNA that gets translated to proteins. Drugs using RNA interference technology blocks the translation of m RNA into problem proteins (disease causing proteins) which means it throws up an entirely new dimension in treating diseases. In other words, these drugs work one step ahead of the chain as compared to conventional drugs----as they prevent the formation of the protein itself. Therefore a whole gamut of diseases from cancer to Alzhemiers to Parkinsonism can be treated further up the disease causing mechanism than what is being done now. Of course there are other mechanisms as well through which biotech medicines can work.
Sirna Therapeutics is a leading company that is actively following the RNAi technology route. It has drugs in the pipeline for treating chronic hepatitis, asthma, Huntington's disease (HD), cancer, diabetes and also for age-related macular degeneration. Another company Alnylam uses RNAi therapeutics technology platform in the specialized areas of oncology, respiratory diseases and metabolic disorders.
Biotech medicines to counter the aging related illnesses
Some small molecules can mimic effects that are similar to calorie restriction which means normal calorie intake gets reduced. It has been seen in research studies that this translates to increased lifespan for animals. In other words, it could slow down the aging process and prevent degenerative diseases that are typical of aging. Sirtris Pharmaceuticals has developed novel proprietory small molecule activators of SIRTI. Activation of SIRTI gene by so called sirtuins (class of seven enzymes related to diseases of aging) is responsible for the beneficial effects of calorie restriction. That apart, sirutins are connected to the pathways that cause type 2 diabetes, cardiovascular and neuro-degenerative diseases.
It is possible that some of these drugs may be used directly in future to counter the aging process, although aging per se is not recognized as a disease and so therapies to counter aging may not be apparently recognized by FDA and other regulatory agencies.
Can Pharmacogenomics help create better drugs?
Pharmacogenomic testing is expected to hasten drug development research. The question is how? In conventional clinical testing, some of the respondents may respond adequately, while others are unlikely to benefit and so this becomes a problem. Using genetic testing, clinical trial respondents can be adequately screened as to who are likely to respond to trials and this translates to shortened period for clinical trials.
Genetic testing before administering medicines
Genetic screening is found to be helpful before administering certain drugs. For example, some patients do not respond adequately to Fluorouracil(5-FU) ( brands Carac, Efudex and Adrucil) which is used for chemotherapy to treat stomach, colon and breast cancers. This is due to a genetic factor ( variations in 2 genes DYPD and TYMS linked to dose limiting toxicities) that makes Fluorouracil highly toxic to some patients. So using a genetic test Theraguide™ 5-FU (developed by Myriad Genetics), doctors can find out these kind of patients and minimize toxicity relating to genetic variation. . Herceptin (trastuzumab) and Erbitux (cetuximab) both monoclonal antibody cancer therapies are only administered to patients who have been tested to ascertain whether their protein receptors would respond to these medicines. Already some drugs have pharmacogenomics information mentioned in their product information leaflets. In future genetic testing may become commonplace, just as using a stethoscope or getting a blood test done.
So pharmacogenomics can not only help create better drugs, it can also help screen a patient's suitability for a drug before administration.
Genetic testing as a diagnostic tool
The pioneering genetics testing company 23andMe has made genetics personal, in that, it has developed a five hundred dollar kit which can identify which versions of SNP's you have. Perhaps you could then reckon that a particular genotype increases your chances of developing a particular disease. However this may not be accurate as they don't sequence the entire genome and so could miss variations. However it does provide an insight into your future health.
As compared to conventional drug development, biotech route to drug development is expensive. Nevertheless, ongoing research is underway in fourteen disease segments namely, AIDS, drugs used in transplantation, drugs used in skin, respiratory, autoimmune, digestive, genetic, growth and neurologic disorders, for treating diabetes, cancer, cardiovascular and eye illnesses and for treating infectious diseases. Amongst this lot, the maximum number of drugs in the pipeline is for treating cancer, followed by drugs to treat infectious diseases and then for autoimmune disorders. However, biotech drug research in developing molecules for eye conditions, for growth disorders and for use in transplantation is lacking.
Reckoning with this trend in the development of biotech medicines, personalized medicine and predictive biomedicine will be treatments of the future. If a person has been prescribed a drug for atherosclerosis and it works fine for that person there is really no guarantee that it would work with the same efficacy for someone else. So in future it may be necessary to design personalized medicine for individual patients and for that pharmacogenomics could come into play. In other words, the conventional way of mass producing drugs may give way to individualized treatment paradigms.
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