Thanks Peter, for a concise and useful explanation on the meaning and value
of FDA approval and clearance. We'd like to add some additional thoughts
along those lines.

HercepTest received premarket approval (PMA) from the FDA for the assessment
of HER2 overexpression in primary or metastatic breast carcinomas to select
patients who may benefit from treatment with HERCEPTIN. Significantly, a PMA
is quite different from a 510k and requires the following:

* For a test to be linked directly to a therapy, such as HercepTest, a PMA
is required. A 510k clearance only allows for monitoring and/or prognostic
evaluation. It is not sufficient for a predictive role to a therapeutic such
as Herceptin.
* A PMA submission involves extensive clinical trials, numerous studies,
data collection and analysis of results. A 510k submission is a much less
rigorous endeavor.
* For a PMA, the FDA requires a site visit to the manufacturing facility. A
510k clearance does not have a similar requirement.
* A PMA requires filing documentation on manufacturing practices with the
FDA. A 510k does not.

What does all this mean for the laboratory?

Importantly, HER2 overexpression is not an all or nothing phenomenon. The
level of overexpression is important and is also easily affected by the type
of reagents used and how they are controlled. For instance, reagent lot
changes, if uncontrolled, may result in different levels of overexpression
from run to run on the same specimen.

To address this, HercepTest offers the following safeguards to ensure that
the results are consistent and reproducible.

* A complete set of reagents that are manufactured according to the approved
FDA criteria. The reagents are matched, controlled and optimized. In
particular, the pretreament reagents are provided and the procedure is
specified. The choice of pretreatment procedure can be a confusing one. DAKO
has evaluated a variety of procedures and submitted an optimized set of
reagents and procedures to the FDA.
* A set of control cell lines are provided. These are included so that the
user can verify that the reagents are working the way they should.
* The reagents are ready to use to prevent further variation.

Finally, to address Andrea's question on automation, we only have data to
support the use of HercepTest on the DAKO Autostainer. Of course, the test
can be used manually.

Do contact out Technical Support group (800/424-0021 or email
techserv@dakousa.com <mailto:techserv@dakousa.com> ) if you have any
questions or comments.

Sarah Sharif
Product Specialist, Clinical Diagnostics
DAKO Corporation
www.dakousa.com <http://www.dakousa.com> 

-Original Message-----
From:	Peter A. Takes [mailto:ptakes@stereotaxis.wustl.edu]
<mailto:[mailto:ptakes@stereotaxis.wustl.edu]>  
Sent:	Wednesday, June 23, 1999 7:38 AM
To:	Andrea Kelly
Cc:	HistoNet Server
Subject:	Re: Her2/neu


Andrea:
I don't know the difference between Dako's product and others; probably a
different clone and possibly different performance characteristics.  How it
actually performs is dependent on how the antibody is supplied (e.g.,
concentration, titer, etc.).
There are a few advantages to FDA approval/clearance.  First, if you are a
clinical lab, many states have invoked rules where IHC tests will not be
reimbursed if FDA-cleared antibodies are not used in diagnostic tests.  This
is the result of recent new FDA rules regarding IHC Abs, and HCFA attention
to IHC and Abs.  Thus, many Ab manufacturers have or are pursuing FDA
clearance on the use of their reagents in diagnostic testing.  Dako and
Ventana are two of the most aggressive companies in this pursuit.  Keep in
mind, FDA approval/clearance does not endorse the performance or use of any
individual reagents, but does attest that individual companies have provided
to the Agency sufficient information that assumes proper performance
evaluation of the reagents has been completed to support the antibody's
indicated use.
Hope this answers your questions.
Peter
--
Peter A. Takes, Ph.D., RAC
Director, Clinical & Regulatory Affairs
STEREOTAXIS, Inc.
Ph. 1-314-615-6964; Pager: 841-9351
ptakes@stereotaxis.wustl.edu <mailto:ptakes@stereotaxis.wustl.edu> 

Andrea Kelly wrote:
	> Can anyone explain the difference between the FDA approved Dako
Herceptest
	> and the other antibodies used for HER2/neu on automatic
[immuno]stainers?
	> Does it really matter whether the detection system is FDA approved
or not?
> Thank you