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Luminex gets 510(k) clearance
for xTAG cystic fibrosis test
By LYNN YOFFEE
Medical Device Daily Staff Writer
Luminex (Austin, Texas) reported that it has received
FDA 510(k) clearance for a new cystic fibrosis (CF) test: the
xTAG Cystic Fibrosis 39 Kit v2, which is designed to detect
the 39 CF-causing gene mutations. It is used to screen
potential parents to determine if they are carriers of CF
mutations, as an aid in newborn screening and in confirmatory
diagnostic testing in newborns and children.
This test is actually a new, improved version for
Luminex. The first iteration was cleared by the FDA in 2005.
“Compared to the previous version, this is faster and
requires less labor,” Jeremy Bridge-Cook, PhD, senior VP,
Assay Group at Luminex, told Medical Device Daily. “The
previous version took about 6.5 hours and this version
takes about 4.5-5 hours depending on the model of thermocycler
used. And the labor time goes down from one
hour and 20 minutes to 50 minutes. The second difference
is that the previous versions of the product recommended
which enzymes to use, but didn’t provide them. In this version,
all of the reagents needed are incorporated in the kit.”
There are about 70,000 people worldwide who have
the disease with 30,000 in the U.S. There is no cure and the
median predicted age of survival is 37.4 years, according to
the Cystic Fibrosis Foundation (CFF; Bethesda,
Maryland).
CF is inherited from parents who carry the mutated
genes but are not sick with the disease. It causes mucus to
build up and clog the lungs, making it difficult to breathe.
That sticky overproduction of mucus can also cause bacteria
to stick to airways, leading to infections and lung damage.
But the problems with CF don’t stop in the lungs.
Mucus can also affect the digestive tract and pancreas,
wreaking havoc on the body’s ability to digest nutrients.
It is caused by mutations in the CF transmembrane conductance
regulator (CFTR) gene. More than 1,500 such
mutations have been identified to date.
Carrier screening is recommended for couples planning
a pregnancy as it is possible for a person to carry a CFcausing
gene mutation and have no symptoms of the disease.
CFF reports that more than 10 million Americans are
symptomless carriers of a CFTR gene mutation. Early diagnosis
of CF in babies allows for earlier treatment intervention
and can help improve a child’s long-term health and
quality of life.
With no cure in sight, the value of a test can be put to
question. But Bridge-Cook said that prospective parents
should be tested because, “If both parents have a CF mutation,
there’s a one in four chance that a baby would have CF.
The utility of information in that context is that it enables
people to make more informed choices from a reproductive
MEDICAL DEVICE INNOVATION 2010
standpoint.
“The other intended indication for the tests is as an aid
in diagnosis of newborns,” he said. “Babies who are diagnosed
early do better and live longer than kids who are
diagnosed later. One of the other aspects of CF is pancreatic
insufficiency. That condition means babies or young children
with CF start to have digestive problems. If its diagnosed
early, dietary measures can be taken that lead to
much better outcomes and longer survival.”
The xTAG Cystic Fibrosis 39 Kit v2 screens for the 23
CFTR gene mutations and four variants (polymorphisms)
recommended by the American College of Medical Genetics
(ACMG) and American College of Obstetricians and
Gynecologists (ACOG), and 16 additional CFTR gene mutations
from human blood specimens in a few hours.
The xTAG Cystic Fibrosis 39 Kit v2 offers physicians
the ability to select the CFTR gene mutations for which they
want to test. Doctors can choose to test a patient for the 23
ACMG/ACOG-recommended gene mutations or the entire
panel of 39 CFTR gene mutations.
This newer version of the xTAG Cystic Fibrosis 39 Kit
v2 will allow labs to avoid having different platforms for
various testing purposes and save time and resources. And
like the first generation xTAG CF test, the new xTAG Cystic
Fibrosis 39 Kit v2 does not require reflex testing. All results
are revealed and available for analysis at each run, if necessary.
Although Bridge-Cook would not discuss the cost of
the test, he did say that CPT coding for reimbursement is
well established and that the cost of the tests is less than
the current reimbursement level, making it “fairly attractive.”
Earlier this year Luminex launched the xTAG Cystic
Fibrosis 39 Kit v2 and xTAG Cystic Fibrosis 71 Kit v2, as CEmarked
in vitro diagnostics under the European Directive
on In Vitro Diagnostic Medical Devices. According to the
European Cystic Fibrosis Society, as many as one in 30
Europeans are carriers of a CF-causing gene mutation. The
xTAG Cystic Fibrosis 71 Kit v2 can screen for all of the genetic
mutations in the xTAG Cystic Fibrosis 39 Kit v2 plus an
additional 32 mutations including those that are typically
found in specific ethnic populations (MDD, June 11, 2009).
Bridge-Cook said a version of the xTAG Cystic Fibrosis
71 Kit is on the way for FDA review and U.S. launch.
(This story originally appeared in the Sept. 8, 2009, edition
of Medical Device Daily)
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