In brief, personalized medicine refers
to the customizing of medical treatment to the individual characteristics of
each patient. Contrary to a common perception, it does not refer to the
creation of drugs or medical devices that are unique to a patient but rather, the
ability to classify individuals into subpopulations that differ in their
susceptibility to a particular disease or their response to a specific treatment.
This information ensures that interventions are targeted only to those who will
benefit, thus sparing expense and side effects for those who will not.
Most medical professionals will concur with the fact that patient response to both disease and therapeutic
intervention are highly variable. It is
not uncommon for one patient to respond beautifully and tolerate a drug without
incident and another to experience side effects while obtaining no
benefit. Depending on the source it has
been documented that 30% to 70% of patients fail to respond to a drug
treatment. There is a variety of
potential reasons including adherence, and even misdiagnosis. Still, it seems highly probable that patient-specific
factors such as variability in drug metabolism rates, the metabolic or genetic nature
of the underlying disease, and other characteristics such as age are also
contributing factors. Enter personalized
medicine.
Oncology is where personalized
medicine appears to making the greatest amount of headway. This makes sense as treatment response rates
in cancer are amongst the lowest for any major disease. The well-established genomic basis of cancer
has put cancer research at the forefront of personalized medicine in the quest
for more targeted and tolerable therapies.
Early examples of success are Herceptin in breast cancer and Gleevec in
chronic myeloid leukemia (CML).
Various technologies are being
employed in the effort to more effectively guide the treatment strategy based
on the likelihood that the cancer will recur or metastasize. For example, the clear molecular differences
seen in breast cancer are highly applicable to genomic profiling, and through
transcriptional profiling approaches, several prognostic and predictive assays
have been developed. Prominent amongst these is Genetic Health’s Oncotype Dx, a
21 gene polymerase chain reaction (PCR) panel that predicts tumor recurrence at
ten years in estrogen-receptor (ER)-positive, node-negative breast cancer
patients receiving tamoxifen therapy. [1] Using a statistically defined algorithm, the
gene expression profile is used to define a recurrence score that can be used
to identify patients who are likely to benefit from additional adjuvant
therapy. Patients with low recurrence scores and, therefore, good prognosis are
spared the stress and risk of unnecessary therapy, and the healthcare system
saves the costs of delivering additional treatment. The assay has been endorsed by both the
Association of Clinical Oncologists (ASCO) and the National Comprehensive
Cancer Network.
Although it is one of the first, and
certainly the one of the most successful to date, it is already clear that
Oncotype Dx is merely the tip of the iceberg. In breast cancer alone, we have
seen the emergence of multi-analyte tests based on techniques as broad as PCR,
microarray, immunohistochemistry and fluorescent in situ hybridization, amongst others. Genomic Health is also expanding the use of
their assay in breast cancer as well as developing similar prognostic test for
colon cancer, prostate cancer, non-small cell lung cancer, melanoma, and renal
cancer.
One of the main obstacles to the
growth of personalized medicine has been cost.
Until very recently the devices used for genome sequencing cost $500,000
to $750,000. Additionally, the
individual tests run $5,000 to $10,000 and take days to produce results. Things are changing though. Just this past year, Life Technologies
introduced an Ion Proton™ Sequencer that is designed to sequence the
entire human genome in a day for $1,000 and the machine
costs $149,000. Clearly, the barriers
to affordability are breaking down. It
is not hard to imagine that the cost of a complete genomic testing will be a
few hundred dollars within a few years. [2]
In order to realize the full potential
of personalized medicine, engagement of multiple stakeholders is critical. Payers will need to be convinced of the clear
benefits of specific genetic tests. As
companion diagnostics are critical to development and utilization of therapies,
the Federal Drug Administration (FDA) will need to promulgate clear and
straightforward paths for diagnostic approvals.
Clinicians will need to modify existing treatment regimens and include
genetic testing as a core component and feel confident to withhold standard
therapies when genetic testing indicates that these treatments are ineffective
or no more effective than watchful waiting.
Treatment guidelines will require modification in order to account for the
genetic makeup of patient populations.
Life science companies will have to develop a new mindset; where the goal
is not the single multi-billion dollar blockbuster but rather a portfolio of
more products which treat smaller populations.
That said there could even be the potential to review the “shelves” of
failed products to determine if there could be success with a more appropriate
genotype or phenotype.
Personalized medicine is upon us and it will
completely revolutionize how treatment is determined. Today, clinicians choose
therapies based on research done on thousands of people that have a diverse
genetic profile and have only a limited ability to adjust therapy based on
individual differences. In the case of
cancer, treatment is currently based upon the tumor location.
In the future, the tumor itself will be tested and it will be based less on
the location than on its genetic and molecular composition. Genomic testing
will be able to identify which oncogenes are turned on and which oncogenes are
turned off. Most importantly,
clinicians will be better able to identify the drugs and treatments that will
yield the greatest benefit to the patient.
We will eventually see this type of therapy for all human illness and will
likely have access to tests that will portend the future and enable patients to
avoid developing conditions such as diabetes, heart disease, and various types
of cancer.
1. Paik, S. et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med 2004.351; 2817-2826.
2. http://www.lifetechnologies.com/us/en/home/about-us/news-gallery/press-releases/2012/life-techologies-introduces-the-bechtop-io-proto.html
Dave Fishman is President of Snowfish, LLC a strategic consulting firm which specializes in helping life sciences companies by using data to address the most challenging issues. More information on Snowfish may be found at www.snowfish.net or by emailing us at info@snowfish.net.
betmatik
ReplyDeletekralbet
betpark
mobil ödeme bahis
tipobet
slot siteleri
kibris bahis siteleri
poker siteleri
bonus veren siteler
MEK