Hello everyone, my father was diagnosed with stage 4 NSCLC with mets to his bones and brain. He was on Tarceva for about 3 months (he felt better within couple of weeks after taking Tarceva) Scans after two months showed "mixed response" pretty much stable disease in his lungs and brain but more growth in his bones. After another biopsy they did not find any T790M mutation but he does have the EGFR(L858R)mutation,his doctor switched him to Tagrisso anyway hoping it would work better for his brain. He had another scan approx 6 weeks after being on Tagrisso and the results are pretty much the same, stable disease in the brain more growth in the bones. After he made the switch to Tagrisso he start feeling a little worst every week, it wasn't anything dramatic but it's something that I and other family members can notice, he just seems more tired and the appetite also got worst. It could be the side effects due to the Tagrisso but our main concern is that for some reason the Tagrisso might not be as effective for him as Tarceva. He was very weak and fragile when he first started on Tarceva but was actually able to gained back some weight in the 3 months of taking it but now he is losing weight since taking Tagrisso.
I understand that Tagrisso supposed to work for EGFR patients even without the T790M but I also saw some earlier studies that indicates the response rate in T790M-negative patients is only around 25% which makes this whole thing very confusing, I could be wrong but I think many studies and trials have shown that the first gen TKIs like Tarceva and Iressa have very high response rate in EGFR(exon 19 and 21)patients, something in the 60 to 70% range so my question is does it make any sense for someone to stop Tagrisso and go back to Tarceva if the condition continue to deteriorate and given the fact that he doesn't have the T790M and was originally responding ok(tho not perfect)to Tarceva? Sorry for the long post, any advice will be greatly appreciated!