by Roger M. Lyons, MD, FACP
As the American population ages and life spans increase,
the incidence and prevalence of blood diseases is expected to
become an important factor in healthcare in this country.
Hematologists, oncologists, and all
physicians involved in the care of our
aging population should be aware
that San Antonio is rapidly becoming
a center for clinical research on cancer
and diseases of the blood. The
research underway here is already
impacting the treatment of several
blood disorders and is expected to
have wide-ranging treatment implications
for the future.
One clinical trial now underway in
San Antonio could lead to a dramatic
change in the treatment of patients
with chronic immune thrombocytopenic
purpura (ITP), a rare, lifethreatening
autoimmune disease. ITP
is a bleeding disorder in which the
blood does not clot properly. The
bleeding is caused by a low number
of platelets, and individuals with
chronic ITP face the risk of bleeding
to death.
The clinical trial involves AMG 531,
a drug now referred to as NPlate® or
romiplastin. Current therapies for
treating ITP are largely directed at
decreasing platelet destruction. Studies
conducted in San Antonio at Cancer
Care Centers of South Texas suggest
that, based on the use of AMG 531,
which is a thrombopoietic growth factor,
chronic ITP may be a result of low
platelet production.
AMG 531 stimulates the production
of platelets through the thrombopoietin receptor in patients with
ITP. This discovery could lead to a
fundamental change in the treatment
of patients with ITP, and it may be
the first step in changing the treatment
of diseases related to low blood
platelet counts, such as may occur
with various cancers.
The results have been so promising
that the clinical trial was featured in
the New England Journal of Medicine
in October 2007 and another article
is “in press” in Lancet. Other medical
research organizations involved in the
trial included New York Presbyterian
Hospital in New York City, Massachusetts
General Hospital in Boston,
and Mount Sinai Medical Center in
New York City.
Results with this drug have been so
dramatic that it is likely the paradigm
for treatment of ITP will change once
the drug becomes available for
patients. AMG 531 is now at the Food
and Drug Administration for review
and consideration for approval.
The results of this clinical trial and
two others involving AMG 531 undertaken
at Cancer Care Centers of South
Texas were presented at the American
Society of Hematology’s 49th Annual
Meeting and Exposition in Atlanta.
One of the other two studies
described in detail the safety of this
drug in controlled phase 3 studies,
and the other reviewed the quality of life improvement seen in phase 3 controlled
studies.
Local research efforts also are focusing
on myelodysplastic syndromes, a
group of diseases in which bone marrow
does not make enough healthy
blood cells. It is one of the most common
blood disorders of older Americans,
and most cases develop in individuals
older than 60. Some patients
have a history of exposure to chemotherapy
or radiation, and MDS is
increasing among older adults as more
of them survive chemotherapy treatments.
In a clinical trial at Cancer Care
Centers of Texas, AMG 531 also was
studied in patients with myelodysplastic
syndromes, with extremely encouraging
early results.
Local research on another medication
for patients with MDS is already impacting
treatment nationwide. Vidaza® (azacycitidine)
was originally given in an
inconvenient seven-day-in-a-row treatment
schedule. Results of this study
showed that a more convenient five-dayin-
a-row treatment schedule reported
results at least equivalent to the sevenday
dosing schedule, with lower complication
rates. Most physicians around the
country are now adopting the new fiveday
treatment regimen for Vidaza, with
a resulting improvement in patient convenience
and compliance as well as
cost savings.
To view various publications on
these studies, visit the Cancer Care
Centers of South Texas website at
www.cccst.com and go to the “Publications” tab.
Roger M. Lyons, MD,
FACP is a nationallyrecognized
hematologist
who practices with
Cancer Care Centers
of South Texas. He is
an active clinical
researcher and his
special interests are
hematology, oncology, and hematologic
malignancies, such as leukemia,
lymphoma, and multiple myeloma.
He has published more than 30 articles
and 43 abstracts and has led 40 research
studies. His work has appeared in
various journals, including the New
England Journal of Medicine, British
Journal of Haemotology, Clinical
Advances in Hematology and
Oncology and Pharmocotherapy.
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