Quantiferon will Sell
for $10 a Dose
Marketing
will target prisons, other big-scale users
Makers
of the new, one-step blood test for detecting latent TB infection
are about to start marketing their product to potential U.S. users
at $10 a test. They’ll market Quantiferon— which won approval
from a panel of the U.S. Food and Drug Administration (FDA) last
October—as a straightforward alternative to the tuberculin skin
test (TST), says Jim Rothel, PhD, chief scientific officer for
Cellestis, Ltd., the Melbourne, Australia-based firm that makes the
product.
CDC
Suggests Using Test as ‘Adjunct’ to TST
That
plan sounded somewhat at odds with comments from at least one FDA
spokeswoman, who told TB Monitor she hoped the Centers for
Disease Control and Prevention, not Cellestis, would work out
procedural kinks before the product hit U.S. shelves. The CDC, for
its part, suggested using the test primarily as an “adjunct” to
the TST.
Rothel
says none of that troubles him. “Well, the FDA asked the panel
[that was considering Quantiferon] whether the test was to be
considered as only an adjunct to the TST,” he says, “and the
panel replied essentially, ‘Why would you want to do that?’ Of
course we want to keep working with the CDC. But we definitely see
this test not as an adjunct, but as a straightforward alternative to
the TST.”
Marketing
would have started already had not the events of Sept. 11 stalled a
visa application. Soon, Rothel adds, the company’s American sales
representative should be set up in his California office.
In
accordance with FDA directives, Cellestis plans to go ahead with
trials of Quantiferon in the two groups for whom the regulatory
agency didn’t grant approval for use: children and HIV-positive
people.
Quantiferon’s
U.S. price will run about $10 a test, says Rothel — or, put
another way, $440 for a kit that tests 44 people. When the cost for
labor is factored in, that’s roughly equal to the cost of
administering a TST and then returning to read it, he adds.
At
least one TB expert says he’s considering switching to Quantiferon.
The $10 price tag “starts to look competitive once you factor in
the time it takes to send someone out to read the TST,” says Jim
McAuley, MD, MPH, the medical director of Cermak Health Services at
the Cook County jail in Chicago. “Not only that, my pharmacy
director just informed me that our price for Tubersol is about to go
up from $2 a dose to $6 or $7.”
Quantiferon’s
logistical advantages are also appealing, McAuley says. As it
stands, Cermak places approximately 100,000 skin tests each year,
but prison TB nurses manage to read only 25% to 30% of them, he
notes. Because it’s a one-step blood test, Quantiferon doesn’t
require going back for a return visit.
McAuley
is an example of exactly the sort of person Rothel plans to target.
“We’re looking at anyone who works in public health where skin
testing is done on a large scale, including jails, immigration
centers, and that sort of situation,” he says.
Next
Generation of Test Already in the Works
Meanwhile,
Rothel says Cellestis is continuing work on an improved version of
Quantiferon that might hit the shelves in three years or so. The new
version would do a better job of distinguishing subjects who are
merely BCG-vaccinated from those who are latently infected with TB,
even though CDC trials show Quantiferon already outperforms the TST
at that task, Rothel notes.
The
next-generation test will work by incorporating recombinant proteins
present in TB but absent in BCG, he says. “These are basically
pieces of the genome which were deleted when they attenuated M
bovis to make BCG,” he explains. “ESAT-6 is the main one
you’ve probably heard of.”
For
now, Cermak’s McAuley says his real challenge will be to figure
out how to persuade his labor force to accept the new technology.
“It’s always painful when you introduce new technology,” he
says. Not that using Quantiferon is that hard, he adds: “I’m not
a lab guy, and even I can do an ELISA,” the basis for the assay,
he says. “It’s just that change always comes hard.”
McAuley
adds that one thing he’s not worried about is whether the test
works. “I read the JAMA article [detailing results of the
CDC trials], and I listened closely to the FDA testimony, and I’m
convinced it’s a good test,” he says.1 n
Reference
1.
Mazurek GH, et al. Comparison of whole-blood interferon assay with
tuberculin skin testing for detecting latent Mycobacterium
tuberculosis infection. JAMA. 2001;286:1740-1747