Is anyone here familiar with The Breast International Group trial 1-07 - the Study of Letrozole Extension (SOLE)
http://clinicaltrials.gov/ct2/show/N...s_ex=Y&rank=15, in which people who've been receiving endocrine therapy for 5 years are swtiched to either continuous OR intermittent (three months on, three months off) AI therapy?
Dr. Ian Smith of the Royal Marsden Hospital discusses these trials in the context of proper dosing for AI therapy in the latest edition of Breast Cancer Update
http://www.breastcancerupdate.com/bc...df/BCU7_07.pdf
He states in relevant part:
"One question about the estrogen receptor becoming hypersensitized when it is reset. If the estrogen receptor is exposed to low doses of estrogen for a long time - as, for example, during prolonged aromatase inhibitor therapy - the receptor seems to be hypersensitive to minute amounts of estrogen.
Another issue is if prolonged exposure to low estrogen doses hypersensitizes the receptor, then maybe we should be administering these therapies intermittently. So the latest idea being tested in clincial trials is intermittent aromatase inhibitor therapy - for example, 3 months on, three months off."
I am wondering if the side effects of continuous therapy would be mitigated with such a regimen? With a substantial number of patients discontinuing AI therapy prematurely due to toxicity, it behooves the medical establishment to look at alternative dosing strategies, particularly when there is evidence that prolonged estrogen deprivation actually promotes a form of therapy resistance through hypersensitization. This may be a good way to maximize efficacy and reduce toxicity. What could be better?
Hopeful
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