Stopping/Restarting Endocrine Therapy?

[Half-Full]

I’ve seen a few posts mentioning that some studies have shown that after endocrine therapy fails, if you stop it and then restart it (months/years later?) it will generally work again, at least for a while. I can’t find these studies. Can anyone provide a link or reference to these studies, or better yet, share your experience if you have stopped and restarted endocrine therapy?

Tumor markers have tripled over the past 3 months on Talzenna, and they have always been very good reliable indicators as to progression, so we will need to change something soon.

Prior therapies included:

- Arimidex for 5 years prior to progression and MBC diagnosis

- iBrance/Faslodex for 2 years

- Talzenna for the past year which now seems to be losing its effectiveness.

We’re wondering if Letrozole monotherapy might be an option. Trying to avoid going to oral chemo (Xeloda) if there’s another viable option. Anything that has a risk for pneumonitis is not an option due to a prior severe case from the iBrance.

Thanks to all.

[Hidden]

Hi Half-Full (me, too, btw! ) -

I don't have a direct answer to your question or related links...

...but you pose an interesting question.

Several years ago (four?) I had seen a link to a study out of...Dana Farber?...that taking an Ibrance break (I know this isn't your question...) for as short as...six weeks?..."re-set" it and gained some additional effectiveness. Either I read or assumed that this was because the cancer mutated "away" from that treatment and then was surprised to see it reintroduced and its defenses to it had reduced...Are you thinking that the same can occur with the endocrine therapies?

Regarding your treatment options, I (not scientific) don't see why Letrozole alone would not be a logical next step. I think most people do *either* letrozole *or* Faslodex in combo with Ibrance and then do the *other* alone? I could be wrong about this...

I'll mention that I did Let+Ibrance for a few years then was able to continue with the Ibrance when I switched to Faslodex...I've been on that combo for 3.5 years.

I don't know if it is now common for folks to continue Ibrance with a second endocrine therapy, but when I did it this was not the protocol. I specifically asked my onc to do this and she coded the change as due to side-effects, not progression (although the change *was* triggered by a bit of progression) in order to get it through "the system" (not sure if the barrier was insurance or standard protocols or ?).

I will look further into your actual question/request and will let you know if I find anything...

Best of luck!

Lynn

[Hidden in reply to Hidden]

Oh! Just re-read your post! I'm so sorry! Okay, Ibrance is not an option but I still see no reason why letrozole is not?

[Godbeforme]

wow! was this ever hard to find again! when I found it two years ago I think I just googled 42 days and it popped up, this time I had to dig and dig! Also, Anne Loeser's book on MBC is very informative and she keeps it updated as far as I know currently. I have been out of the loop. hope this answers your question, I stayed off of Letrozole for almost a year but now numbers rising and back on it although trying it every other day because I want to be to keep using my hands. God bless you and heal us all in Jesus name, amen! <3 ncbi.nlm.nih.gov/pmc/articl...

[Dragonfly2]

Im so sorry about your current challenges..I hope you do find a way forward!Here is a link regarding the stopping and restarting of endocrine therapy .

pubmed.ncbi.nlm.nih.gov/284...

In addition, I had consulted with Mary Chamberlain at the Dartmouth Hitchcock Hospital in Lebanon NH....she also had reassured me that there are very good indications that this temporary interruption in endocrine therapy can sometimes trigger a renewed opportunity to use it again . I hope this works for you!

Unfortunately I have heard that in some countries the option to use this therapy is reserved for a one time use....which seems so cruelly unfair . Best of luck!😘

[Half-Full]

Thank you all so much for your responses and the time it took you to find the linked studies. Looks like I need to brush up on my Googling skills.

It would be nice to hear of some success stories though from anyone on the board that has tried restarting aromatose inhibitors after discontinuing due to progression…