Biology Reference
In-Depth Information
this chapter will review the contents of this document. The full guidance document can be
reviewed at the following link:
http:
//
www.fda.gov
/
medicaldevices
/
deviceregulationand-
guidance
/
guidancedocuments
/
ucm262292.htm
(accessed December 2012). The guidance is
intended to cover all sponsors for whom a device is required to ensure the safe and effica-
cious use of a therapeutic, as well as those choosing to develop the device in association with
an intended therapy. With the evolution of personalized medicine and an increasing occur-
rence of the development of a device to enhance therapeutic efficacy, the FDA has deemed it
necessary to regulate such devices to assure physicians and consumers of the reliability of the
analytical performance of the test.
7.2 D
EFINITION OF AN IVD COMPANION DIAGNO
STIC
The first goal of the guidance document is to establish the definition of an
in vitro
diag-
nostic (IVD) companion diagnostic, in order to clarify further discussion. The guidance
document describes an IVD companion diagnostic device as 'an
in vitro
device that pro-
vides information that is essential for the safe and effective use of a corresponding therapeu-
tic product'
[1]
. The word
essential
here could potentially cause some confusion. Although
those devices enhance the performance of a therapeutic, they are
not
required in order to gain
approval for the therapeutic. To clarify this further, the document specifies those devices that:
1.
identify patients that are most likely to benefit from a particular therapeutic product;
2.
identify patients likely to be at an increased risk for serious adverse reactions as a result
of treatment with a particular therapeutic product;
3.
monitor response to treatment for the purpose of adjusting treatment (e.g., schedule,
dose, discontinuation) to achieve improved safety or effectiveness
[1]
.
While this definition would appear to clearly identify those devices intended to improve
patient response to a particular therapy, there is some ambiguity in the statement 'clinical
laboratory tests intended to provide information that is useful to the physician regarding the
use of a therapeutic product, but that are not a determining factor in the safe and effective
use of the product.' Given the definition provided in this guidance document, it would
appear that there is still a place for laboratory developed tests (LDTs)
1
in association with a
therapeutic product, assuming the product can achieve approval without the device. An
example of this would be a device that may improve patient response rates in a subgroup,
but in which the therapeutic response rates in the overall population are sufficient for
approval of the therapeutic. While this has not been a frequent occurrence in the companion
diagnostic devices that have been approved to date, it is important to note this nuance in the
definition, as the regulatory approval process for an IVD companion diagnostic and labora-
tory developed test differ. An additional item of note is that this definition specifically2
2
explains the history of the test and its relative impact on the device's classification.
1
Typically well described tests used to diagnose diseases and conditions and historically intended to be used
by physicians within a single institution. The components of traditional LDTs were regulated individually
by the FDA as general reagents (though this is not the case entirely today), and the tests are developed and
offered in CLIA-certified laboratories.
2
FDA
/
CDRH Public Meeting: Oversight of Laboratory Developed Tests (LDTs), Date July 19-20, 2010.
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