Re the elevated biomarker: from patients I have seen (and again, I'm not an oncologist, but have treated many patients with cancer), I think a very realistic explanation for her dropping out is this: Getting into the study in the first place was a Hail Mary pass. Ovarian Stage 4 has a 17% survival rate, I believe. She was in the safety (not efficacy) phase of the study. She was feeling awful (no energy, had ascites) and has likely been feeling that way for some time.
Now, all of a sudden, she feels so good, she can hike with her family. Ascites gone. Maybe she has more hope for the first time in a long time, or maybe she doesn't really have any more hope, but believes that for whatever time she has left, she'll now have a better quality of life, thanks to K. She likely can't read PET, CT, MRIs, etc and depends on others to interpret them. But, what she can understand and see for herself (and thus likely feels she has more control in decision making about - don't underestimate the loss of control cancer pts feel) is the marker. It's a simple number. It goes up and down. (And as others have said, it can be influenced by many things, including those having nothing to do with cancer.) She's suddenly feeling better than she has in a long time, but her number goes up 10%. She has always been told and likely experienced that it generally correlates with her cancer worsening/spreading. She may have gotten scared (who wouldn't) and decided not to tempt fate, be happy with what K has given her, maybe try a different trial that looks at efficacy in some other compound, or maybe just live whatever time she has left to the fullest and not be burdened by more trials. (Maybe there's even something on her bucket list she really, really wants to do, and now can, if she leaves. Maybe she's been telling herself for the past year or two, "If I ever feel better, I'll.... ") Especially when she's feeling so much better, a higher number is scary - as she got a taste of feeling close to back to normal, and was afraid that her feeling that way wouldn't last long unless she tried something else/stopped K.
Someone mentioned her oncologist. He/she likely has nothing to do with the study and may not even know much about K. She or her family may have been the ones to find the study. We don't know what advice the oncologist gave her, but ultimately, it was her decision to leave, and I feel very confident we should read absolutely nothing into it re K.
