[Sandy in Silicon Valley]

Hi, Donna -

I think that the answer to your question comes from how the two drugs have been tested...

The Tykerb Phase III trial that GSK ran was exclusively for patients with bcmets, whose mets had progressed while they were on Herceptin, and who were willing to take Xeloda along with the Tykerb, and come off any other systemic chemo they were on. That's a fairly limited subject pool, out of all the people who will eventually get Tykerb off-label, as I am (taking it WITH Herceptin, and without any systemic chemo).

Herceptin has been tested, and found synergistic with, numerous chemo regimens. It does have the LVEF damage possibility - but not everyone gets that side effect (I haven't, in 4.5 years of effective Herceptin use), and has very few/minor other side effects. Plus, the left ventricle heart damage is reversible, if found on time, and Herceptin patients are monitored for signs of CHF (in which case, they're taken off the Herceptin).

Tykerb has nastier side effects, and for more of the patients taking it: rash/acne & itching/pain associated with the pruritis, and diarrhea. It isn't known how effective it is, or for which bcmets patients, or whether it is effective in an adjuvant setting (prior to dx with bcmets). It isn't known which chemo regimens it might work well with, and which might result in worse side effects, or might be antagonist (work against each other).

Personally, I'm taking Tykerb b/c I've had brain mets, and the Herceptin can't get through the BBB (blood brain barrier), being a large molecule drug. Tykerb is a small molecule drug, considered able to get through the BBB to prevent/decrease brain mets. But the verdict really isn't in yet about how effective it is, for how many HER2neu+++ patients. So it's a gamble... if my brain mets progress, I will go off the Tykerb, but stay on Herceptin, and possibly try another small-molecule biologically-targeted drug, like Sutent.

(((hugs)))
Sandy in Silicon Valley