Different people but
less differentiated drugs
A drug can be highly effective for one patient
but, the same drug might not show the desired result when given to a
second patient with the same diagnosis and even be harmful in a third
Today half the medicines fail to produce the desired effect; only
around half of all patients actually benefit from their drug treatment.
This situation particularly is unsatisfactory for patients or doctors
because neither the desired effects nor the side effects can be clearly
defined or reliably calculated; and it is unsatisfactory for health
insurers too, as they will be pay for treatments whose quality leaves a
lot to be desired in many cases.
This is where the concept of personalized healthcare steps in.
What is personalized
Personalized healthcare (PHC) is about fitting treatment to patients to
obtain better clinical outcomes. It is based on the concept that the
treatment will be selected based on patient characteristics that become
known through molecular diagnostic tests.
PHC recognizes that we are all individuals and that the
‘one-size- fits-all’ approach is not effective.
While a drug can be highly effective for one patient, the same drug
might not show the desired results when given to a second patient with
the same diagnosis and even be harmful in a third one.
Based on the knowledge of disease biology, the mechanisms of actions of
the drugs and the biological differences between patients as well as
the characteristics of their disease, we are now able to tailor
treatments and diagnostic tests to the needs of specific patient
populations. It is a treatment tailored to specific needs of individual
groups with shared features (eg., genetic characteristics), who can be
grouped together in such a way that treatments can be optimally
tailored to their needs. The approach of PHC is to use new molecular
insights and molecular diagnostic tests to better tailor medicine and
better manage disease.
Potential of PHC
Conventional medicines have traditionally been prescribed on a
‘trial-and-error’ basis, that is effective about
half the time. This approach results in a large number of adverse drug
reactions and misdiagnoses—which are in part responsible for
approximately 200,000 deaths every year in the US alone.
Today, response rates to treatments vary from 20-75 percent, depending
on the drug and the disease. For that reason, patients and physicians
are demanding better care and safer and more effective treatment.
A century ago, blood cancers were known simply as ‘disease of
the blood’. Today, cancers of the blood have been separated
into 90 distinct leukemias and lymphomas, each with its own distinct
Breast Cancer: One of the greatest advancement in the treatment of
breast cancer is the drug, Herceptin, (trastuzumab) which targets HER2
positive breast cancer, a type of breast cancer that is known to be
more aggressive. However, we know that not every patient responds to
this treatment.Approximately 25 percent of breast cancer patients have
HER2 gene over-expression. By measuring the presence of the growth
factor, HER2, in breast cancer through a specific HER2 test can
determine the HER2 positive beast cancer patients who will respond to
Herceptin, therewith improving outcomes and reducing costs by treating
only those patients who benefit.
Colorectal Cancer: An excellent example of personalized healthcare at
work is the KRAS mutation test.This test helps direct treatment for
patients afflicted with metastatic colorectal cancer. Recently,
scientists have developed more targeted therapies for colorectal cancer
that look at limiting the growth of the cancerous cells. One such
therapy is the epidermal growth factor receptor (EGFR) inhibitor (or
anti-EGFR therapy), which prevents growth signals from entering the
cells, thus stunting the growth of the tumor. Patients with a mutated
KRAS gene (35 percent-45 percent of metastatic colorectal cancer
patients) are unlikely to respond to EGFR inhibitors. With the
TheraScreen KRAS mutation test, both doctors and patients will have a
better idea on which treatment option to employ for greater
Lung Cancer: The TheraScreen EGFR 29 Test designed to enable detection
of 29 of the most common somatic mutations in the EGFR gene and detects
mutations not visible by sequencing. Recent studies in non-small cell
lung cancer (NSCLC) have shown that some patients carry somatic
mutations in the EGFR gene. These mutations may correlate with
responsiveness to the EGFR tyrosine kinase inhibitors, a targeted
therapy for NSCLC.
HIV: The way in which HIV patients regularly test their viral load is
one of the earlier examples of personalized healthcare. A patient will
have their viral load tested (along with a CD4 cell count) when they
are first diagnosed with HIV – this acts as a baseline. They
are then tested again two-six weeks after they begin their treatment to
evaluate whether therapy is effective.
Subsequent tests are carried out every three to four months to monitor
long-term therapy to ensure the patient has not developed a drug
resistance. The advent of tests has helped HIV turn from
being an acute short term disease, to a chronic disease.
HCV: Hepatitis is a viral infection that can go undetected in the body
for years. Left untreated, it can lead to cirrhosis, liver failure and
cancer. Detection and treatment are essential in the early stages when
the likelihood of cure is relatively high. Tests that diagnose and
monitor the virus in the blood and treatment with drug, Pegasys, have
helped many of the people who have been infected. However, not all
patients respond equally to this treatment. A HCV viral load test
measures early response to therapy with drugs such as Pegasys, while a
test that identifies Hepatitis C virus subtype provides information
that helps to determine the correct duration of treatment with such
A shorter treatment duration with Pegasys/Copegus will provide patients
with full benefits of therapy while reducing unnecessary drug exposure.
The four-month treatment course will be for patients with particular
strains of chronic Hepatitis C (genotype 2 or 3) who have low virus
levels before starting treatment, and who show a rapid virological
response by clearing the virus from the blood within the first four
weeks of treatment. This is a new treatment concept in Hepatitis C,
which seeks to customize regimens for patients based on how well they
respond to treatment.
Diabetes: Diagnostics provides blood glucose tests to tailor insulin
treatment to patients’ needs. This is one of the first uses
of personalized healthcare in modern medicine.
Osteoporosis: A broad range of tests are made available to assess bone
integrity and to monitor the effects of anti-resorptive therapy with
drugs such as Bonviva/Boniva. They show response much earlier than bone
mineral density. Further simple causes, such as Vitamin D deficiency is
common in 60–70 percent of the Indian population.
Now there is a pharmacogenetic test to analyze variations in two genes
that play a major role in the metabolism of many widely prescribed
drugs. This is the world’s first commercial pharmacogenetic
product for predicting individual drug response that implements gene
chip technology. Examples include drugs such as Warfarin.
Mycophenolate mofetil is an immunosuppressant to prevent the body from
rejecting a kidney, liver or heart transplant. The key metabolite is
mycophenolic acid (MPA). An immunochemistry-based test measuring MPA,
guides optimal patient dosing. This enables doctors to accurately
tailor these dosages and to safely lower dosages of more toxic agents,
thus further improving the outcome for patients.
Medical science continues to achieve rapid significant advances in
treating patients. Understanding how patients are different and respond
differently to a medicine is fundamental to learning how to treat
disease at the right time and with the right medicine.