c-erbB-2 Response

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From:Dave Tacha <dtacha@ncal.verio.com>
To:"histonet@Pathology.swmed.edu" <histonet@Pathology.swmed.edu>
Date:Tue, 20 Jul 1999 08:16:18 -0700
Content-Type:text/plain; charset=us-ascii

Thanks to all who responded about c-erbB-2 dilemma.

Summary of Responses:

1.  It appears that the Dako c-erbB-2 is an FDA premarket approved (PMA)
kit, which is much more extensive than 510K approval.

 2.  However, individual laboratories do not have to use Dako's PMA
Herceptin Kit, and patients can received treatment by using their own
in-house methods.  However, the Dako kit has been tested and approved
with extensive clinical trials, and it is probably advisable and it is
highly recommended to use.

3.  If an individual laboratory does not want to use Dako's kit, it is
highly recommended that the individual laboratory does a side by side
and/or validation study. If you choose not to,  you may be taking risk
that potentially may put patient health care at risk.

4.  A written protocol for in-house studies should be established.
Below is a sample test for c-erbB-2 or any in-house validation method
for prognostic antibodies.  As technologists and health care providers,
I think it is important that we establish some sort of validation
criteria not only for c-erbB-2, but other assays such as ER and PR and

    A.  A suggested in-house validation method:

    Stain a minimum of 20-30 cases of c-erbB-2 positive and negative
tissues with your standard and/or existing laboratory
    protocol and compare results with the Dako kit.  A side by side and
comparison study should be done to validate your
    in-house protocol.

    You can also send cases to a reference lab, such as Impath, for

    After validation testing, the individual laboratory can use there
own protocol and/or screen with their own protocol first, and
    then confirm with the Dako kit.

5.  No one, including Zymed, has not responded  to the rumor that Zymed
has an FDA approved c-erbB-2 antibody.  One can only assume that this
was a rumor without substantiation.

6.  Although studies have found that the 3+ staining criteria is best
for patient response to treatment with Herceptin, 2+'s are not excluded
by any "law".

The above information was a summary of information received from a
Histonet response, including a response from Sarah Sharif, Product
Specialist from Dako Corporation.

If there is any additional information that needs to be stated, and/or
if any of the above information is incorrect, your response will be most

David Tacha HTL (ASCP)
Biocare Medical

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