Personalized medicine

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Personalized medicine is the use of detailed information about a patient's genotype or level of gene expression and a patient's clinical data in order to select a medication, therapy or preventative measure that is particularly suited to that patient at the time of administration. The benefits of this approach are in its accuracy, efficacy, safety and speed. The term emerged in the late 1990s with progress in the Human Genome Project. Research findings over the past decade, or so, in biomedical research have unfolded a series of new, predictive sciences that share the appendage -omics (genomics, proteomics, metabolomics, cytomics). These are opening the possibility of a new approach to drug development as well as unleashing the potential of significantly more effective diagnosis, therapeutics, and patient care.

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[edit] Limitations of traditional medicine

Traditional diagnosis focuses on the symptoms of a patient's illness whereas a personalized medicine approach can directly examine and analyse the genetic basis of a disease and stratify the total population into different sub-sets each with common, but unique, disease characteristics.

The pharmaceutical industry has worked on the basis of offering a therapy that is intended to suit the population at large based on what is known as the 'blockbuster drug model'. A blockbuster drug is a product capable of achieving sales of over $1 billion per annum. The pharmaceutical industry is facing severe difficulties across several spectrums with its blockbuster approach:

  • A great number of patients suffer adverse side-effects from prescribed medicines. Deaths (as a consequence of adverse side-effects) are statistically very significant. If a product, such as Vioxx, has to be recalled from the market, the consequences are far reaching and enduring.
  • It costs an average of $1 billion and 12 to 15 years to develop a new therapeutic and further $1 billion to successfully market a new product. The failure rate of product development is very high and in many cases failure is not evident until a great proportion of this investment has been committed to large scale clinical trials.
  • Despite spending in the region of $27 billion and employing the genius of almost 200,000 scientists on research and development, very few new, unique, therapeutics have emerged over the past decade.
  • Many established branded blockbuster drugs are coming, or have already, come to the end of their patent-protected lives. These products can typically lose up to 40% market share in the year following patent expiry as generic alternatives become available.
  • Consumer knowledge is making the market more cost sensitive.

[edit] Response of stakeholders to personalized medicine

There are several stakeholders: the industry, the regulators, the payors, the patients and the general public

[edit] Pharmaceutical industry

The pharmaceutical industry, in general, has been reluctant to the immediately embrace the potential of personalized medicine. It is believed that they are concerned that the emergence of personalized medicine will destroy the foundations of the mass-market blockbuster drug model because personalized therapeutics will cater for particular sub-sets of the general population.

Another reason for the scepticism of the pharmaceutical industry is the threat to existing products. Many blockbuster drugs, such as Lipitor, compare favorably with cheaper generic drugs only in a small percentage of patients. But since it is not known how to identify these, many physicians prescribe the expensive drug to all their patients. If a test could be devised to determine who actually benefits from the more expensive drug, all other patients could use the generic.

However, the technologies underpinning personalized medicine could enable the pharmaceutical industry to become more sure-footed. A more efficient drug development process, based on sound, robust genetic evidence could require less investment and, perhaps less elapsed time, to identify and develop new products as confidence deepens. Furthermore, the idea of a therapeutic being marketed on the basis of a companion theranostic test result could deepen and prolong consumer loyalty if sustainable benefits are evident.

[edit] Diagnostics industry

The traditional diagnostics industry is mature and only achieving a growth rate of the order of 4% per annum. Its products are very cost sensitive and have a relatively short life cycle. The diagnostics industry has not been as successful as the pharmaceutical industry in attracting investment funding.

However, the advent of molecular diagnostic tests, or theranostics, opens new opportunities in a small but believed to be rapidly growing niche market. New relationships are likely to develop between industry partners committed to personalized medicine embracing the approach of successful, specialised pharmaceutical firms. Such has been the case with IBM. This corporation has made strategic partnerships with Mayo Clinic Medical Center and several other healthcare and testing centres. Its plan entails developing bioinformatics systems which will allow greater growth in tests that are available.

Still the major problem in growth of tests such as these is their clinical utility as well as reimbursement from third party payors.

[edit] Customers

The emergence of personalized medicine raises issues for those who pay for treatment. The unit cost is likely to he higher but it is argued that the total cost of a treatment cycle will be lower overall. Furthermore, the possibilities of the predicitive potential of personalized medicine ought to avert costly intensive care treatment when a disease is established.

The response of payers will be influenced by the nature of the relationship they have with those whom they are paying for. Is it a long-term relationship, which is the case with nationally funded medical care, or is it short term? New policies and procedures will be necessary.

Countries such as the United States are currently struggling with the burgeoning of healthcare expenditure. Perhaps personalized medicine is the cure. However, most US private insurers unlike the governmental system are not embracing this potential. Less than 5% of all private companies reimburse for genetic tests.

[edit] Regulators

The Food and Drug Administration in the United States and their counterparts appear convinced that personalized medicine is going to make a profound impact on society and they are guiding this process.

Dr Andrew VonEschenbach, Director of the FDA recently gave a briefing to the Personalized Medicine Coalition at the National Press Club. He and the organization are truly committed to bring new testing and treatment to market which is molcularly based. His feeling is that the Molecular Metamorphosis is equivalent if not greater than the bacterial theory and its revolution of medicine.

[edit] United States Policy

Personalized medicine has the potential to revolutionize the practice of medicine, but despite significant scientific advances, very few genomics-based tests or treatments have reached consumers. Senator Barack Obama introduced the Genomics and Personalized Medicine Act to overcome the scientific barriers, adverse market pressures, and regulatory obstacles that have stood in the way of better medicine.[1]

[edit] Patients

Patients will clearly be influenced by proven success as is the case with Herceptin and Gleevec. Theranostic tests are proving effective in other areas such as the identification of anti-retroviral drug for use with different strains of HIV.

At a recent meeting of the US Secretary's Advisory Committee on Genetics Health and Society it was revealed that a majority of the public supports the utilization of genetic testing, especially if this testing could be used to improve health outcomes.

[edit] Public

Public education public confidence about the potential benefits of personalized medicine will be an important facet of its widespread acceptance. This includes about the research itself and the science underlying it; disease variations and the approach to prevention, treatment and care; and a deeper awareness of risks and benefits attaching to clinical trials.

[edit] Collaboration, infrastructure and technology : key enablers

The march toward personalized medicine is not driven, in some instances, on the basis of scientific hypothesis but through hypothesis generation sometimes starting with natural history. The key task is to find genes and gene variations that play a role in a disease. The first step is to associate the occurrence of a particualr gene variant with the incidence of a particular disease or disease predisposition - an association that can vary from one individual to another depending on many factors, including environmental circumstances. The outcome is the development of biomarkers which are stable and predictive. Today's biomarker is tomorrow's theranostic.

The infrastructure necessary includes molecular information -biological specimens derived from tissue, cells, or blood provided on the basis of informed donor consent and suitably annotated. Clinical information is also necessary based on patient medical records or clinical trial data.

A very high level of collaboration involving scientists and specialists from varying disciplines is required to integrate and make sense of all this information.

The Harvard Partners Center for Genetics and Genomics was founded in 2001 with the specific goal of accelerating the realization of personalized medicine. The Personal Genome Project was announced by George Church in 2006; it will publish full genome sequences and medical records of volunteers in order to enable research into personalized medicine.

Not only is personalized medicine tailoring the right drug, for the right person, at the right time but it also includes evaluating predisposition to disease sometimes decades in advance of its threatened onset.

[edit] Personalized medicine and cancer

Cancer genetics is a subspecialized field of genetics. This field initially dealt with the relatively small amount of inherited cancers. This amounted to about 5-10% of all cancers as estimated bt the National Institutes of Health.

Individuals diagnosed with familial breast, ovarian, colon cancer had been counseled in the past that they would receive standardized treatments and had limited options before their "condition" arrived. These options included removal of the organs that may give rise to cancer. Recent medical research indicates that medications, lifestyle changes and increased screening can mitigate some risk. An example is BRCA mutations where the carrier can have an increased lifetime risk of 85% for developing a breast cancer or up to 40% increased risk of getting ovarian cancer. Now medications such as tamoxifen are being shown to reduce incidence of disease.

The exciting news is that cancer predisposition genes and families are being identified by genetic testing and research at a break neck pace. Because all cancers require a dysfunction in the DNA of cells that regulate growth, it would be foolhardy not to expect all cancers to have some heritable predisposition as well as environmental influence.

Personalized medicine aims to identify these families at risk for cancer, heart disease, diabetes, etc. Once identified by simple family history including a 3 generation pedigree or advanced genetic testing, the person could take preventative action. This might include changes in diet, cessation of toxic habits, earlier screening, exercise, prophylactic medications or surgery.

[edit] Herceptin and Gleevec

Two products, Herceptin supplied by Genentech and Gleevec supplied by Novartis,are prescribed on the basis of the outcome of a companion theranostic test. Herceptin treats a category of breast cancer in woman and the test helps identify those patients whose cancer cells express the protein HER2 making them eligible. Herceptin sales have grown from $30.5 million in 1998, its year of introduction, to $764 million in 2005. Gleevec treats chronic myeloid leukaemia (CML) arrived in 2004 and it is known as a targeted cancer drug. In addition because of new molecular testing for c-kit, tumors such as GIST GastroIntestinal Stromal Tumours a solid malignancy never associated with blood bourne cancer are also treated with this drug. It works by killing specific cells whereas chemotherapy can kill both deranged and healthy cells. Because of this ability to molecularly detect true disease causing mutation a whole new reclassification of cancer has begun. So has the unimagined use of several of these "targeted" drugs. Gleevec sales have exceeded $500 million.

[edit] Personalized medicine and education

There are several universities involved in translating the burgeoning science into use. The difficulty is that medical education in all countries does not provide adequate genetic instruction.

A small number of universities are currently developing a subspecialty in medicine that is known by several names including, molecular medicine, personalized medicine, or even prospective medicine. These include, Duke University in North Carolina USA, Harvard in Cambridge USA, The Mount Sinai Hospital in New York City. A medical school is currently being constructed in Arizona USA to teach the field of personalized medicine; this is a project of Arizona State University and a company called TGen.

Aside from academic universities, private programs such as Helix Health LLP in New York City provide genetics consultation to accomplish personalized medical care. Their mission is to educate and empower patients and physicians in this new paradigm of medicine.

[edit] See also

[edit] References

  • Sadee W, Dai Z. (2005), Pharmacogenetics/genomics and personalized medicine, Hum Mol Genet. 2005 Oct 15;14 Spec No. 2:R207-14.
  • Steven H. Y. Wong (2006), Pharmacogenomics and Proteomics: Enabling the Practice of Personalized Medicine, American Association for Clinical Chemistry, ISBN 1-59425-046-4

[edit] External links

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