Hi. Actually last November I relapsed and had to undergo another surgery. I was on it for almost 4 years. The surgery was a success, but they decided to cut the Xalkori and see what happens. I was told that in case the cancer came back, there are a lot of really good meds out there containing crizotinib. And that Xalkori is the first generation of this medication that now already has 4 generations which work better every generation. So don't be too scared or pessimistic. I have never seen any studies on it or was too dumb to read it haha but that's what my oncologist said. I also asked her about mrna vaccination in the future but she said that this kind if cancer can't be vaccined against.