Comparing effectiveness of Tarceva and Iressa - 1253730

Iressa and tarceva have very similar qualities and efficacy. The standard dose for tarceva are a bit higher than the equivalent standard dose of iressa. But prescribing one over the other isn't thought to make much difference. Insurance and availability is usually the contributing factor in which one is taken. Too if you are doing well on an anti cancer drug it's usually a very good idea to "ride the wave" of efficacy as long as the side effects aren't too bad.

I'm not able to access our search engine and have a call out to Mark our tech guy about that.
Here is a link to our blog/posts on the subject of EGFR with a measly 250 blog posts. You can thin that out some on the right column under archives. http://cancergrace.org/lung/?cat=26

In the meantime I'll make sure Dr. West or Weiss comments.

Best of luck with continued success on Irresa.
Janine
forum moderator

The short answer is that there's no real evidence that Iressa (gefitinib) or Tarceva (erlotinib) is a better choice than the other for an EGFR mutated patients. They show remarkably similar efficacy in EGFR mutation-positive NSCLC patients, and modestly greater side effects with Tarceva at 150 mg, probably really quite comparable in side effect profile with a dose reduction of Tarceva. I think just about every lung cancer specialist considers them to be interchangeable choices for EGFR mutation-positive patients, and I would say that many consider there to be a modest superiority for Tarceva over Iressa in the patients who are EGFR wild type (no mutation).

-Dr. West

mkdr, congratulations on your excellent results on Tarceva, and I hope they continue.
I wonder if your question was more about Tarceva vs Iressa in people with an Asian profile? From what I understand, the reasons why Tarceva is used in the US and Iressa in Asia relate to drug regulation regimes in different countries. I suspect Dr Pennell's comment was based on a clinical trial, and the clinical trial was based on whichever of the two drugs was available to the investigators at the time.
Anyway, it sounds as if you are on a drug that is working for you, and that the most important thing. Best wishes.

For EGFR mutants, there's no clear indication of one being better than the other. Iressa, at standard dosing, is effectively less medicine, with less side effects, but no clear difference in outcomes. In practice, many US oncologists, with access only to tarceva, start at lower than standard dosing in order to try to replicate something closer to the standard iressa experience.