Estradiol after xtandi/zytiga failure- anyone seen a response?

[Shanti1]

Hi Everyone-

Although my husband has metastatic prostate cancer, this question is for a friend whose husband is metastatic and is no longer responding to Xtandi. For those of you using estradiol, has anyone seen a response to estradiol after the failure of Xtandi or Zytiga? She realizes there are other options as well (chemo, provenge, xofigo, genetic testing).

Thank you

[pjoshea13]

Hi Shanti,

I don't know about estradiol, but how about ethinylestradiol? [1]

"Thirteen patients (92.9%) achieved a decline in PSA, 8 patients (57.1%) achieved a decline in PSA > 50%. Time to progression was 0-18 months (median 7 months), and there were no severe adverse events including venous thromboembolic diseases." [2]

There have been a number of studies using DES against CRPC.

-Patrick

[1] en.wikipedia.org/wiki/Ethin...

[2] ncbi.nlm.nih.gov/pubmed/249...

[Shanti1 in reply to pjoshea13]

Hi Patrick-

Thanks for the response, the paper you posted gets closer to an answer. I also found this one on the estradiol patch in CRPC: ncbi.nlm.nih.gov/pmc/articl.... Both studies indicate some efficacy of estrogen administration after resistance to GnRH analogs/combined androgen blockade, but estrogen administration after resistance to Aberaterone and the newer androgen receptor blocker such as Xtandi was not evaluated. I don't think this question has been looked at in a study, and I have a feeling there wouldn't be much of a response, but I thought I would check to see if anyone has tried it.

Warmly,

Shanti

[Break60 in reply to pjoshea13]

I thought DES was stopped in favor of estradiol patches due to CV events.

[pjoshea13 in reply to Break60]

DES doses used to be very high - 5mg & up. But I know a number of men who today use 1mg (sometimes only every other day). My BAT variation seems to need 2mg/day for me.

There did used to be clotting issues at 5mg, but 1mg seems to be safe. I monitor D-dimer (as we should, anyway) & adjust nattokinase dose accordingly. There is no pharma alternative, and the E2 patch is definitely safer than oral DES.

DES wasn't "stopped in favor of" E2, but following FDA approval of Lupron in 1985. Lupron was much more expensive, so I'm sure that many men continued to use DES.

Wiki: "In the 1990s, the only approved indications for DES were treatment of advanced prostate cancer and treatment of advanced breast cancer in postmenopausal women. The last remaining U.S. manufacturer of DES, Eli Lilly, stopped making and marketing it in 1997."

-Patrick

[abmicro]

Dont know if it will help after failing those 2 powerful drugs, but cant hurt to try the estrodiol patch while getting ready for a more effective treatment, your "other options". Usually cancer does not like any new ADT drug you try, and after you start something new, cancer immediately starts thinking of ways to become resistant to it.

My experience showed that the patch helped me with hot flashes, memory, osteoporosis, joints, and contributed to my overall ADT. I took a daily coated baby aspirin with it per recommendations from my MO. I had a good PSA response at first running 9 patches, but after 6 months, cut to only a half of a 0.1 patch (=0.05) to control hot flashes and osteoporosis. (I was combining other ADT drugs during those 6 months.)

[Shanti1]

Thank you for sharing your experience. My friend's husband is thinking to add in the E2 patch as you mention while determining the next steps. His bone density is not good and he has a host of other ADT symptoms, so at the least, he may get some benefit around these other aspects.