Stopping Abi?

[Gatodd]

I meet with my MO Thursday. We will likely discuss coming off Abiraterone, as my 2 year anniversary is upcoming. Probably continue on Eligard for another year, following stampede trial.

PSA reached undetectable early in my treatment and remains undetectable. SE. aren’t fun, but manageable. Don’t know the specific SE associated with Abi vs Eligard, since treatment on each commenced at the same time.

How likely is the risk that stopping Abi after 2 years could allow remaining cancer cells to develop immunity, thus making Abi ineffective upon recurrence?

[JohnInTheMiddle]

REWRITTEN FOR CLARITY DECEMBER 8TH

I'm looking forward to any answers from knowledgeable people. Because the question is almost backwards from what I am worried about. The poster's question concerns the risk of Abiraterone (an ARPI therapy against PCa) losing it's anti-cancer effectiveness because of a holiday.

I'm metastatic so I don't take holidays. And I'm on Abiraterone and Firmagon forever. But it is this continuous therapy, the ARPI and the ADT therapy, which is suppressing the androgen and the signaling work that it does, that thereby is powerful evolutionary pressure on the PC.

The fear of evolutionary pressure is why there's several different protocols which add up to "brief holidays from therapy" - in order to take the pressure off. If you take the therapy pressure off maybe we can slow down evolution to therapy resistance. (I will be grateful for any correction on this note.)

[jedgar1 in reply to JohnInTheMiddle]

I did two years of Zytiga and Lupron and got a one-year holiday. I got nine months went back on zytiga and Trelstar. The trelstar side effects, much less than the Lupron, night sweats with the Lupron were terrible.

[Gatodd in reply to jedgar1]

Thanks. My MO is comfortable coming off zytiga as per the Stampede study.

[GP24]

If you PSA value is undectable you could stop both and decide for intermittent ADT. Restart at a PSA value of 5.0 ng/ml according to the Embark trial protocol.

[Concerned-wife in reply to GP24]

My husband was advised by leading center if/when his PSA rose to 2.0 to obtain a PSMA scan to determine whether he needed to come off his vacation.

[GP24 in reply to Concerned-wife]

It makes sense to get a PSMA PET/CT at a PSA level of 2.0 ng/ml to look for metastases and decide if these shall be radiated.

There is no PSA level which is commonly used to end the vacation. Usually the patient and his doctor agree on this when starting the vacation. I used the value used in the Embark trial to determine the end of the vacation.

[JWPMP]

My husband has been undetectable for aprox 2 years. He is close to completing his 3rd year of ADT/HT. Doctors offered vacation last January, with taking action when PSA reaches 0.2. He decided against the vacation.

He's being treated at UCSF.

fwiw

[Nfler]

The thinking is the other way around, Abi usually works for two years n then any remaining cancer cells become castrate rstn. If you get off at the two year mark, hopefully there are no more PCa and psa stabilizes forever. If not you can always get back on Abi if you choose to continue that route, furthermore ivermectin has shown to make castrate rstn cells sensitive again. I chose to get off Abi n ADT after seven months n only use ivm and psa has been cut in half ( opposite of psadt) from 1.95 to.95 in less than a year. So go ahead n enjoy your time off Abi as it always will b there until it’s not, imo…

Good luck 🍀

[Gatodd in reply to Nfler]

Thanks. I decided to eliminate Zytiga, effective on my 2 year anniversary on Sunday.

[Nfler in reply to Gatodd]

Good call