Tamoxifen and CYP2D6 metabolizer

DianneS · 10-02-2009, 12:29 PM

I am considering Tamoxifen. However I am learning that there is a test, the CYP2D6 metabolizer status, which can tell whether Tamoxifen would improve outcome based on your metabolizer or cause/promote cancer growth in poor metabolizers.

Anyone have this test? I would like to know more about it!!

Thanks,
Dianne

DianneS · 10-03-2009, 12:18 PM

Aw shucks. I was hoping to get some response. Hasn't anyone been tested before they went on Tamoxifen to see if they are weak, strong or? metabolizers? I just need to know if you were tested - and the test is called the CYP2D6, was it done by bloodtest or cheek swab?
Thanks,
Dianne

WolverineFan · 10-03-2009, 06:56 PM

I have not heard of this test, but will finish my chemo this Tuesday (yeah!!). I am assuming my onc will discuss Tomixfen in my appt with her on Tuesday, so I will ask her about it. Thanks for the heads up.

Debbie L. · 10-04-2009, 04:42 PM

Being a good CYP2D6 metabolizer doesn't guarantee that Tamoxifen will be effective for an individual. But it's looking pretty sure that Tamoxifen does not do much for the other (much smaller) group - the poor metabolizers.

I've heard it said that one way to do this is just to take the Tamoxifen and see if you get side effects like hot flashes. If you do, you can be assured that you're a metabolizer. If not, maybe then it's worth getting tested, as there are many metabolizers who do not get side effects - the other way round (no se's) doesn't tell you anything for sure.

But this whole question is awaiting more evidence. That's why docs are slow to move on it - they're waiting for better information. That said, I don't really see a downside to doing the test, unless it's really expensive. Do you know how much it costs?

And while we're on the topic, there was one study (SABCS 08?) that found an association between response and se profile for AI's, also - although I don't think they have any idea what the mechanism would be there, as they do with the CYP2D6 theory for Tamoxifen.

Debbie Laxague

schoolteacher · 10-05-2009, 10:36 AM

I have had this test. I requested the test after learning about it here on the board.

I have the genes to be a good metabolizers. In December, I have been on Tamoxifen for a year.

Amelia

DianneS · 10-05-2009, 01:09 PM

Hi,

I called the company that does the testing - Genelex. They are sending me a specimen kit; basically a cheek swab that I do at home then send it back to them for analysis. They will send a report to me and my doctor as well. The cost is relatively cheap - $295 and it takes about 2 weeks. I asked for a STAT test so it's $100 more. But I am seeing my doctor soon and need to know if I'm a candidate for Tamoxifen or not. I am weakly ER positive.

At any rate this company Genelex sounds very interesting. The DNA that they are testing for me will tell me about other drug interactions as well. You get a 30-90 day trial subscription to their website which lists all of the drugs and how they interact with your DNA - after that period you can either pay $24 a year for the service or drop it. Not only drugs are to be listed on the software but anything you take - supplements, herbal, whatever. They can very much interact with drugs.

I live in Canada and the cost of the test is not reimbursed, but I can't complain as everything else to do with medical here is free....but I think some insurance companies in the States will pay for it. The fellow I spoke to said that the slowness in getting this test available to everyone is largely controlled by the huge pharmaceutical companies in the States (no brainer there!) who don't want people to know how their drugs interact. He said drug interactions are the 4th leading cause of death (I think it's 4th) so I think this information is good to know.

The number for Genelex is 1-800-523-6487. I called the Mayo Clinic but they wanted me to have 'an account' before they would continue! I thought they were not for profit....anyway if anyone has info about Genelex or wants more info I'd be happy to share what I know.

Dianne

AlaskaAngel · 10-08-2009, 01:29 PM

http://her2support.org/vbulletin/sho...608#post211608

TSund · 10-08-2009, 04:35 PM

Ruth had the "tamoxifen metabolizer test" upon recommendation of our onc, who is a pretty well known researcher. Makes sense to me to have it.

What's interesting to me is that the research of tamoxifen vs AI's did not include this test, which potentially flaws the data some and bring the results of the two drugs even closer together. That being said, Ruth will be switching within 6 months or so.

Best,

Terri