225AC PSMA617 treatment any idea?

[Nirman]

225AC PSMA617 anyone have idea about this? When should be done or survival benefits etc before chemo or after chemo?

[GP24]

My understanding is that Ac225 is not available in India?

[Nirman in reply to GP24]

Yes it is at Fortis hospital

[GP24]

I would not get Ac 225 monotherapy because of the side effects of dry mouth etc. Better is a mix of Ac225 and Lu177. I would get it before chemo because I think it is more effective than a chemo, particularly because your father has bone mets. See this study:

researchgate.net/publicatio...

[Nirman in reply to GP24]

Okay thank you for the advice

[GP24 in reply to Nirman]

I forgot to add the conclusion of the study:

Conclusion: In the present multicenter analysis, chemotherapy-naïve mCRPC patients receiving [177Lu]Lu-PSMA-617 therapy had a significantly longer OS than patients with a history of chemotherapy.

[Tall_Allen]

It is more powerful than 177Lu-PSMA-617, but the extra cancer-killing power brings with it higher salivary gland toxicity. Some places in Germany are mixing the two to reduce toxicity.

prostatecancer.news/2021/01...

Survival benefits are undoubtedly greater if used earlier. But it is an open question whether chemo may sensitize the cancer to radiation. Based on a trial of docetaxel and Ra223, I expect that it will improve survival with 225Ac-PSMA617 too. Only a randomized clinical trial will give a definitive answer.

[GP24]

You can also sensitize the tumor for the Lu177 therapy with Enzalutamide:

eurekalert.org/pub_releases...

Enzalutamide increases the PSMA expression.

[tango65]

The main indication for the Ac 225 PSMA treatment is bone marrow infiltration by the cancer. If they use Lu 177 PSMA in these circumstances , more bone marrow could be damaged.

Ac 225 PSMA emits alpha particles which travel a smaller distance than the beta particles emitted by Lu 177 PSMA. With Ac 225 less normal cells adjacent to the cancer will be affected by the radiation.

If the cancer is not causing bone marrow infiltration you could consider Lu 177 PSMA treatment instead. Besides Lu 177 PSMA does not destroy the salivary glands.

[Nirman in reply to tango65]

And how would I know about bone marrow infiltration?

[tango65 in reply to Nirman]

Ask for a PSMA PET/CT (Ga 68 or 18F DCFPyl). you will need one anyway,