I'm fine with sharing privacy-wise; my reluctance is because my story is a downer.

I knew before I hit the maximum number of chemo cycles that it wasn't working very well and that I wanted to try a clinical trial. So I had a biopsy done to get the tumor sequenced. I should have done this earlier, although the foot-dragging hospital, which took a month to send the specimen to the sequencing company, didn't help.

This showed a mutation in a gene called ATM, among others. ATM-mutant tumors are sometimes sensitive to drugs that inhibit a functionally related protein called ATR. This is known because something like eight different ATR inhibitors have gone into clinical trials over the last 10 years. There have been complete responses for high grade endometrial cancers (like mine) with ATM mutations. But there have been no phase 3 trials, and definitely no FDA approvals for any of these drugs, which suggests a problem with this class of drugs. But I plowed ahead. And learned by personal experience what the problem is.

Two weeks into the trial, I landed in the hospital for 4 days with 0 neutrophils, a high fever, severe anemia, and feeling dreadful. The infamous neutropenic fever. I needed a transfusion. But I felt like it had worked on the cancer, and the CA125 and later CT scan suggest there was probably a~50% reduction in the tumors over this period.

So after an extra week off and with a ~50% dose reduction, I started the second cycle. That has gone much better in one sense; I don't feel too bad and have neutrophils. But my suspicion is that it's no longer working on the cancer either. I'll see the CA125 on Monday. So I suspect that the problem with these drugs is that there is no dose at which they're both safe and effective. You can have one or the other.

If I don't see the numbers going down (not just remaining stable), I'm going to quit the trial and give Lenvima/Keytruda a try. But that's basically accepting that there's zero chance this will end well (which I knew intellectually already but hadn't really accepted.)

Sorry for the TMI.