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Herceptin, approved in 1998, was developed specifically
as a result of genetic research. Although other new
drugs targeted at specific diseases will continue to
be developed, most early-stage targeted medicine most
likely will involve therapies already on the market.
Diagnostic testing probably will comprise much of the
first phase of genetically targeted medicine, pharmacogenomic
researchers say. At first, it probably will not be cost-effective
to test people for every medication, even if tests are
available, said Cynthia Prows, MSN, RN, a clinical nurse
specialist in genetics at Cincinnati Children's Hospital
Medical Center.
Early testing may be limited to drugs that have a narrow
therapeutic range, are highly toxic or costly, she said.
But eventually, many who work in genetics predict, the
tests could become as routine as blood sugar or cholesterol
screenings.
"I think the day will come when before anybody
gets a drug, there will be a test to determine how you
will respond to it," said Steven Seelig, MD, Ph.D.,
divisional vice president of research and development
and chief medical officer for Vysis Inc., the Chicago
company that developed Herceptin.
Genetic information eventually may allow health care
workers to target medical procedures and lifestyle interventions,
as well as medicines. Researchers are looking for a
correlation between genetic markers and the way patients
respond to stents, said Lorraine Frazier, DSN, NP, RN,
associate professor at the University of Texas Health
Science Center at Houston School of Nursing, who is
researching genetics and markers of cardiovascular disease.
Similar information may predict how environmental factors
like stress and diet affect-or don't affect-physical
conditions.
"Do all patients with high blood pressure need
to decrease their salt intake? Probably not," Frazier
said. "We used to give patients guidelines that
were ineffective, that probably affected their quality
of life. In the future, we'll look at the patient genetically
and physically."
Growth industry. Although no one can say when
targeted medicine will become commonplace, everyone
agrees that the health care workforce needs to prepare
for it now. "The current estimates are three to
five years before widespread application of pharmacogenomics
occurs," Engler said. It is imperative, she said,
that nurses have a basic understanding of pharmacogenetics
"and genetics, for that matter. We need to keep
pace with the explosion of new knowledge."
Linda McAllister, MD, Ph.D., director of medical genetics
for Celera Diagnostics in Alameda, Calif., sees an immediate
need for nurses with a good understanding of genetics
in the research field, as pharmaceutical companies scramble
to search for new diagnostic tests and therapies that
can be targeted to certain genetic variations. "The
research aspect is potentially a huge opportunity for
nurses," she said. "In a way, it's a kind
of career opportunity and a growth industry for this
area. We will need to do clinical research on a very
large scale."
As more genetically targeted therapies come onto the
market, nurses will need to be able to explain how they
work to patients, said Dale Halsey Lea, MPH, RN, assistant
director of the Southern Maine Genetics Services Foundation
for Blood Research in Scarborough, Maine. They will
need to explain that the targeted therapies are something
new, that patients may have different responses to them
and that long-term effects and possible side effects
have not yet been evaluated.
Nurses also will need to educate patients about genetics
and about how they may have a condition or gene variation
that is or isn't responsive to a particular therapy,
Halsey Lea said. Parents of children with cancer frequently
compare types and doses of medicines their children
are taking, Masny said. They also use the Internet and
research available therapies. Nurses will have an important
job in helping them to understand how each patient's
therapy is personal and not necessarily exactly the
same as for other people who have the same illness or
who are taking the same drug.
"This stuff is complicated and it's difficult
for people to understand. A lot of doctors don't understand
it," Seelig said. "If I were a leader in nursing,
I would get nurses to be the primary educators of genetic
content information, to know the language of genetics
and how to communicate it to patients. That's a way
nursing could reassert control of the profession in
the health care industry."
Understanding the relationship between genetics and
medications also may help nurses better understand their
patients' needs, especially for pain medication. Research
suggests that between 1 percent and 10 percent of the
population are ultra-rapid metabolizers. Genetic tests
eventually may determine who metabolizes pain medication
more quickly and what kinds of pain medications are
most effective.
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