If casodex switches to feeding PCA

[Scootman]

If casodex switched to feeding PCA would not XTANDI do the same thing since they are similiar drugs?

[noahware]

Good question! But even if it did switch, does it necessarily really matter? You'd want to stop using it if it stopped working for you and putting the cancer to sleep. That would be true whether or not it actually was HELPING the cancer. Same goes for Casodex.

My philosophy is if something stops working, going back to it after a break makes less sense than moving on to something different.

Let's suppose Casodex has a resistance mechanism different from that of other AR inhibitors or antiandrogens. The fact is, for many many men, their cancers can and do find a work-around and develop resistance to ANY of these meds.

One hopes that any resistance is detected in PSA changes, and same goes for the possibility that a med may switch its roles from a cancer-fighter to a cancer-feeder.

I have come to think that ANY hormonal treatment used continuously may eventually lead to developing more lethal and less treatable variations of PC. So my goal, as advised by Dr. Bob Liebowitz, is to avoid becoming castrate-resistant. This would seem to mean taking periodic breaks, even in the face of a rising PSA?

[Tall_Allen]

Yes, it does, and it has been described, but it is much more rare with Xtandi. In clinical practice, the androgen receptor will usually become resistant before it is used as "food." While they are both antiandrogens, Xtandi has much greater affinity for the androgen receptor, and it is much more difficult to use as a ligand. Oddly enough, it can also happen with Zytiga. A biochemist explained that an abiraterone metabolite can act as a ligand at the androgen receptor.

[mklc in reply to Tall_Allen]

Good morning Tall Allen,

I trust you are keeping well during this most difficult times?

AS Cassodex is still being very effective in keeping my PSA at undetectable, SHOULD I at this stage switch to Zytiga or just stay on the Cassodex and Lupron?

Sincere thanks. Mike

[Tall_Allen in reply to mklc]

Zytiga + Lupron increases survival much more than Casodex + Lupron.

[mklc in reply to Tall_Allen]

thank you so much Tall Allen. Much appreciate your reply. Please keep well. best wishes.

[immunity1 in reply to mklc]

Re use of abiraterone and enzalutamide. Apart from TA response above, it appears to be better to use Abiraterone and then move onto Enzalutamide later when A fails. Rather than the other way around. I anticipate using an androgen receptor antagonist (bicalutamide because of cost or enzalutamide) in the near future even though it failed with me 3.5y ago. R

[mklc in reply to immunity1]

Thank you so much for sharing your insight and knowledge. I am most grateful. Wishing you good health and a nice summer.

[RyderLake2]

Hello,

I don't think so for the reasons given by Tall Allen. Early in my treatment when my PSA started to go up my oncologist suggested I go off Casodex (bi-calutamide). Darn if my PSA didn't go down. Three years ago I started Xtandi (enzalutamide). After about two years, my PSA started creeping up. When I asked my oncologist (a very wise man) if I should get off Xtandi, he told me to stay the course. Darn if my PSA didn't go down to almost undetectable for reasons neither he nor I could properly explain. This is an anecdotal story I know, but even though Bi- and Enza are in the same family of drugs, I don't think you can draw this parallel between them. Hope that helps!

[LearnAll]

What is the harm with re-challenging with bicalutamide ....after a gap of few months...there is possibility that the effect will come back. It does happen with many medicines.

[Scootman]

Thank you all just another thought I had because it seems my mind never shuts off to this. Can't get a reprieve now I am waiting on a bone biopsy which has me pretty nervous. Hoping they don't tell me something worse than I already know and hoping something better comes out it.

[Peterd110 in reply to Scootman]

Hoping with you!!

My mind never shuts down either. 😕

[RICH22 in reply to Scootman]

i had bone marrow biopsy... found mds cancer, with dna damage... -5q . Taking a potent chemo that goes after the weird red blood cells, but probly not the marrow cells that produce them. Good luck, brother.

[Patrick-Turner]

I had a friend who had Casodex added to his ADT which began to fail after 3 months after his RP and some following salvation IMRT. The casodex sped up the rise of Psa and I was told that where that happens, both Casodex and Xtandi may be useless. Anyway, my friend went to Docetaxel which worked for 4 shots to get psa from 40 to 2, but after 10 shots it was 40 again.

His DNA was analysed and he was suitable for PARP inhibitor so they used that on him but but Psa went from 40 to 432, and he got new mets in his liver and got very sick and died, all within 3 years of diagnosis, before he turned 60.

This was terrible luck for him and for his beautiful wife of 50, and his two kids.

He had good doctors, but they all were completely out-witted by his cancer.

Try to stay well and be cheerful,

Patrick Turner.

[j-o-h-n in reply to Patrick-Turner]

Thanks for cheering me up........

Good Luck, Good Health and Good Humor.

j-o-h-n Friday 05/15/2020 6:14 PM DST

[RJ-MN]

When my CaP first went systemic I was placed on a combined androgen blockade of bicalutamide and lupron. This suppressed my PSA for less than a year before it began climbing. I stopped the bicalutamide, and my PSA dipped to <0.1. My Mayo status was "in bicalutamide-withdrawal-response" for just short of two years before PSA began rising again. A few years after that I entered a clinical trial @ the NIH where I was given enzalutamide (+ Prostvac-Tricom immunotherapy). My PSA nadired @ 0.02, and I was on the clinical trial for more than 5 years. So in my case bicalutamide was at first efficacious but then turned into an agonist; its removal gave me two years of stability @ <0.1 PSA. Then about 4 years later I had a great 5+ year run on enzalutamide. There's more to their bodily differences than focusing on the androgen receptor or ending in -mide!

[RICH22 in reply to RJ-MN]

yes, i've tallied 4 stories how enzalutamide carried on the bicalutamide work successfully. that's my plan, if my bical. fails.

[RICH22]

which premise? that casodex can turn to feed cancer or that xtandi could also feed cancer?