Is a stronger steroid switch advisable for use with Abiraterone

[Ronnie7C]

After my 6 sessions of chemo, PSA dropped to 5.6

In April 2021 started on Zytiga 500mg + Prednisone 5mg. In May ’21 PSA dropped to 0.5

Due to high cost of Zytiga, I switched to the generic version Abiraterone in May ‘21

PSA continued results as follows:

June ’21 - Oct ’21 PSA remains at 0.02 (had switched to 250mg with low fat breakfast)

Apr ’22 - 2.01

Aug ’22 - 6.6

Sep ’22 – 8.7 (had switched to 1000mg on empty stomach)

Oct ’22 – 8.8

Nov ’22 – 12.0

Combination of Abiraterone + Prednisone is failing to stop PSA from rising.

Would taking Abiraterone with a stronger steroid (e.g. Dexamethasone) help to revert the continued rise in PSA results?

Will discuss this matter with my oncologist at our next meeting. Meanwhile, would appreciate any users views an advice on this subject.

[Tall_Allen]

Get a bone scan/CT - if it shows progression, I doubt switching to dexamethasone will help. No harm in trying.

[Ronnie7C in reply to Tall_Allen]

Thanks TA. Will see about getting new scans and having comparisons done.

[TeleGuy]

It's not that dexamethasone is stronger, it's that it is different from prednisone and the cancer can start feeding on prednisone. Just search for abiraterone and dexamethasone in the posts and you'll see many discussions on the topic.

[Ronnie7C in reply to TeleGuy]

Thanks for your comment, much appreciated

[HopingForTheBest1]

Keep in mind that long term (years) steroid use can lead to the development of cataracts. which I have. As always, there are positives and negatives for every treatment.

[Ronnie7C in reply to HopingForTheBest1]

That's so true. Thanks for the advice, I'll keep an 'eye' out for that

[Bspouse]

I have not been able to find any studies showing that switching from prednisone to dexamethasone might make the abiraterone start working again. Does anyone have any studies I can use to show my MO IF the current abi + prednisone stops working?

[TeleGuy in reply to Bspouse]

Here's an excerpt from "Lessons from the SWITCH trial" which is one of several papers on the topic:Several hypotheses have been proposed to explain the responses observed in the earlier SWITCH study2 including, but not limited to: [I] the emergence or selection of cells with secondary AR mutations that are activated by prednisone but not dexamethasone;8 [II] a differential downstream transcriptional effect of 0.5 mg of dexamethasone versus 10 mg of prednisone in cells overexpressing the GR as a bypass mechanism to AR inhibition and [III] secondary activation of the mineralocorticoid receptor, which has higher affinity for prednisone.

Here’s the article:

nature.com/articles/s41416-...

[Bspouse in reply to TeleGuy]

Thank you! This is just what I was looking for. I will show to MO so we can keep it in mind for the future.