Tarceva question - 1253105

Hi Sherry, In light of the newest discussions about the correlation being more probable I think that's a rational question to ask.
This is the latest of Dr West's post on the subject, http://cancergrace.org/lung/2012/11/25/topical-rash-and-egfr-outcome/

I'll contact a doctor for comment on your question.

I hope you are OK, you have a place in my heart,
Janine

Hi Sherry, thanks for your question since many people on Tarceva end up wondering the same thing. There is some evidence that patients who get a rash with Tarceva have, on average, a better chance of benefiting from the drug than those who get no rash at all. This is not a strong association, and many patients who get a rash get a modest benefit or ever no benefit at all while others with no rash at all have tremendous responses, but if you had to pick I would say getting a rash is better than no rash at all. The problem with that, of course, is that having a rash is never fun and at the extreme end can be very uncomfortable. We have ways of managing the rash, such as adding topical steroids and an oral antibiotic like minocycline, but some patients simply have to reduce the dose of Tarceva in order to get the rash to the level they can tolerate.

What no one has ever shown, however, is that patients who GET a rash at a normal dose in any way "lose out" on potential benefit by reducing the dose to the point that they can live with the rash. I try to reassure patients that dose reduction is built into the trials that show benefit from drugs like Tarceva, and dose reduction is simply a part of the process of finding the right dose for the individual patient.

Of course, I generally try to maximally manage the rash in other ways before I start reducing the dose, and then I try to only reduce the dose to the level that is livable for the patient. Many people find the longer they are on the drug, the better the rash gets (although not true for everyone). I assume that because you are at 50mg that you must have been very sensitive to the drug, and if that is the highest dose you can live with then so be it. Be assured that the lack of rash in and of itself really means nothing in your specific case about whether the drug will work or not!

I understood Sherry's question slightly differently - as asking "if you've had a rash and it clears up, does that mean the drug has stopped working?" - ie if your side-effects reduce or go away, does that say something about the effects of the drug?
Sherry, I don't know how long you've been on Tarceva, but my experience is that the side-effects improve over time and then return in a muted or a different form. So - as Dr Pennell describes - I don't get the rash as I did at the outset, but I'll get sudden outbreaks from time to time, often in very unexpected places. Then it'll be calm again for a while. Same with the diarrhoea - I'll get weeks of discomfort and then everything will settle down for a few months. All best.

Sorry, to answer the direct question “if you’ve had a rash and it clears up, does that mean the drug has stopped working?”, the answer is no. You have simply dropped the dose to the point that it doesn't cause skin toxicity, or in certain spring's example, your body has adjusted to the drug enough that the rash goes away. The disappearance of rash does not mean the drug is not still working on the cancer.