My profile is updated, but briefly, diagnosed de novo, high volume metastatic in April 2022. PSA 28.2, Gleason 4+5. ADT & 6 rounds chemo brought PSA to 0.48 in Jan. 2023 & then started creeping up. In June, went over 2 & MO felt was castrate resistant. Stopped abi. and started Keytruda (I am MSI- high, high TMB, MMR gene deficient) near end of June. PSMA PET showed about a dozen mets, all in bone, no organ or soft tissue. PSA at 1st infusion was 2.73, over 10 at 2nd and 18+ three weeks later. I'm scheduled for labs, see MO and 3rd infusion this coming Monday.
So, based on PSA, Keytruda isn't working. I know tumor microenvironment is harder to penetrate in bone than soft tissue. I know it sometimes takes 3 - 4 infusions to kick in, but how high can I let my PSA rise? My thought is do 3rd & see where PSA is 3 weeks after. If still rising, time for a change. My options are another SOC or clinical trial.
SOC could be Xofigo (as all mets in bone) or Pluvicto or cabazataxel. A concern about all those is that my white count took almost 5 mo. to come back to normal after my final chemo, despite Neulasta. There's Provenge, which maybe could help T cells to get thru to the cancer cells??
Then, there's clinical trials. My MO suggested one as a possibility - phase 2 for XmAb®20717, which targets PD-1 (what Keytruda does) & CTLA-4. Concerned that no response to PD-1 may not bode well for this. I've read about a couple others with bispecifics, though both are phase 1.
Planning to have liq. biopsy done next week and ask about scans (prob. CT as likely too soon for PSMA PET). Do most people turn to clinical trial after all SOC tried or do you do a trial that may be promising and return to SOC if need? TIA
Have to make a decision next week 
Update after 3rd Lu177
Docetaxel/Taxotere. 2nd time in 3 years. It's a no go this time. No benefit after 3 infusions.
What scan should I get?
