Retreatment with Pluvicto
Started by xrt123
PSMA scan still shows PSMA uptake in bones and visceral disease but improved since prior to Pluvicto. 6 cycle at 200 mCi per cycle. Interruptions. GFR is 60. Labs are all appropriate, (Hgb 11 plt and white count are fine). PSA dropped form 400 to 5 with Pluvicto treatment now risen to 40 over 11 months. Med Onc says he has nothing else to offer.
I think you can consider retreatment.
But you will need to be careful about toxicity (no-brainer!).
I'd perhaps think about getting an FDG-PET too, just to be certain there are no discrepancies in the uptake (areas that no longer show uptake in PSMA but only in FDG).
But you will need to be careful about toxicity (no-brainer!).
I'd perhaps think about getting an FDG-PET too, just to be certain there are no discrepancies in the uptake (areas that no longer show uptake in PSMA but only in FDG).
D
deleted804959
General consensus is that we're overtreating and/or improperly treatment timing cycles. At this point I would be careful as the delayed renal and marrow toxicity will present around now. Your goal is to have enough of a PSMA-positive tumor burden to serve as a tumor sink (controversial term) for the Pluvicto to reduce exposure to already irradiated kidneys and marrow. Compare the pre-Pluvicto PET (I hope it was DCFPyL, but if PSMA-11, it's fine) to quantify mean tumor SUV as a sort of surrogate for PSMA-avidity/expression. You can do this on MIM if you have access to it, or ask your NucMed to quantify SUV metrics in a particular area (especially if symptomatic). If the patient is asymptomatic, I would wait until they become symptomatic to treat. There's no point in trying to rush things if asymptomatic, as I'm guessing the disease recurrence/persistence are in lesions that were present prior to Pluvicto, so you're basically just delaying the inevitable, or even hastening renal/marrow failure.
Another option is to consider Actinium on trial if that's an option for where you are. Probably the #1, 2, and 3 best options are palliative consult, palliative consult, and palliative consult.
I tend to space out my Pluvictos more than what is textbook, and am very comfortable stopping after 2 cycles to keep further treatments in my pocket when needed. I get PSMA PETs after every 2 cycles. The little published data for more than 6 cycles shows what you'd expect...bad news bears.
Another thing to consider is disease transformation, for which getting an FDG PET would be helpful. In these cases, if the tumor burden is disproportional with PSMA-avidity and PSA, be concerned for neuroendocrine transformation and potentially consider sending out for TMBs for possible palliative immunotherapy.
Another option is to consider Actinium on trial if that's an option for where you are. Probably the #1, 2, and 3 best options are palliative consult, palliative consult, and palliative consult.
I tend to space out my Pluvictos more than what is textbook, and am very comfortable stopping after 2 cycles to keep further treatments in my pocket when needed. I get PSMA PETs after every 2 cycles. The little published data for more than 6 cycles shows what you'd expect...bad news bears.
Another thing to consider is disease transformation, for which getting an FDG PET would be helpful. In these cases, if the tumor burden is disproportional with PSMA-avidity and PSA, be concerned for neuroendocrine transformation and potentially consider sending out for TMBs for possible palliative immunotherapy.
We're bringing Pluvicto to my practice and I'm trying to get a sense of how people view the cut offs. The hematologic ones seem pretty straightforward, but how are people assessing patients with the creatinine clearance? I've seen 50 thrown around as a cut off, but is this a strict cut off? Is there any wiggle room?
Basically, how are you assessing patients for Pluvicto eligibility with a borderline creatinine clearance?
Basically, how are you assessing patients for Pluvicto eligibility with a borderline creatinine clearance?
Also, congrats! Pluvicto is a good long term play that I think will payoff for rad oncs who own it
Thanks! Now if only I can get the Nuc med department to call me back so we can figure out the scheduling. The logistics are the tricky part.
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I do, but one year is a little short. I’d try to space it out. Especially since the PSA is still rising slowly. No urgency to treat right away from what I am hearing. FYI, I also usually stop after 4 upfront if they have a good response. The most we have done so far (cumulatively) in a patient is 12. The Germans have done up to 17. I agree with above, we probably give too much up front to the initial responders and we don’t know how long to space them out. With renal being late, it’s hard to know.
This is making a really good clinical rationale for dosimetry
Absolutely. We (and many other groups) are trying hard to get adequate funding to do in vivo dosimetry in a meaningful way. Do you have to give 200 mCi if tumor burden is below a given threshold for the same effect? Does actual dose received to the kidney help you decide how many cycles to give? Just a small taste of the questions we and others want to ask. I like to thing radio pharma is a little further along than pointing a KV cathode tube at someone’s skin. But on the continuum of that to VMAT, we are definitely still closer to taking shots in the dark at this point in time.
With prolonged consent I have done it for eGFR above 30. There is some literature showing limited risks. I did not have any noted changes in kidney function and marrow in the 2 patients treated with eGFR 30-40. And I made sure they were super hydrated at any lab draw. We are starting in vivo dosimetry with 2 spect scans after the first cycle to track this.
How is that possible without physics and a hot lab?
Probably using a trailer? Portable setup. How pet scans are done in some large groups, esp with multiple treatment sites
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I haven't confirmed but I'm hearing similar....of some wild set ups.
An authorized user (rad onc or IR) off site (in this case about 90 miles away at a main site) is signing off on the dose, ordering, etc....then a PET tech delivers the dose.
Yeah not sure of the supervision rules. I don't think that is actually kosher. NRC regulations, not CMS
