rebecca2015
![]()
Posts:19
Hi,
My boyfriend's oncologist is recommending for him to change drug from tarceva to iressa as an alternative drug, not a second line. He did his 3 months CT and PET scan around two weeks ago. The CT scan foundstable tumor, but not much shrinkage. The PET scan found two new lesions. He will be doing a urine test to test resistance to tarceva this week. Why would the doctor not want to go to second line immediately? Also, would you recommend he stop tarceva for a few weeks prior to starting on iressa?
Thanks so much for your help!
EGFR, NSCLC
Forums
Reply # - July 28, 2015, 08:10 AM
Hi Rebecca,
Hi Rebecca,
Most oncologists do not move from Tarceva to Iressa, or vice versa, as the two drugs work in a very similar manner and if anything, Tarceva is considered to be a bit more effective. As Dr. West has written:
"[T]here’s no real evidence that Iressa (gefitinib) or Tarceva (erlotinib) is a better choice than the other for 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)." -http://cancergrace.org/topic/comparing-effectiveness-of-tarceva-and-ire…
As far as his oncologist not recommending a switch to second line therapy at this time, it may be a question of the significance of the progression noted on the latest scan. You like to get the maximum benefit from a therapy before moving on to another.
All that being said, I don't know that there's any harm in making the switch, or any reason to wait before making the switch. Tarceva has a half-life of just 36 hours, so in a week it should pretty much be out of his system.
JimC
Forum moderator
Reply # - July 28, 2015, 10:23 AM
Thank you, JimC. I was also
Thank you, JimC. I was also wondering at what point do oncologist make the decision to go into second line treatment? His oncologist is doing a urine test for resistance test. Does it test for the T790 gene mutation or would he need to do another biospy or blood test. My understanding for the literatures I've read is that blood test is still not available for clinical oncologist. Is this correct?
Thanks,
Rebecca
Reply # - July 29, 2015, 07:57 AM
I'm almost certain blood
I'm almost certain blood testing for T790 is available outside clinical trials. Here are a couple of posts on the subject of liquid biopsies, http://cancergrace.org/lung/category/lung-cancer/core-concepts/liquid-b…
Oncologists like to use a treatment until they feel sure it's no longer working. If the tumors are still smaller than they originally were then staying the course is usually the decision. If there is just one or 2 areas of progression and other spots are still stable after several months or years on tarceva/iressa focal treatment is often used and tarceva continued. How the cancer behaves (is it aggressive or indolent) will determine how quickly one might want to move on to another treatment. Dr. West has written a lot on this subject. Your question is one of what to do and how to know when there is acquired resistance. This is a good place to start,http://cancergrace.org/lung/2013/01/23/acquired-resistance-algorithm/
and for more reading and listening, http://cancergrace.org/lung/category/lung-cancer/general-lung-cancer-is…
I hope this is helpful,
Janine