HER2 negative but actually a low positive and neratinib

kaynotrealname

I'm making a list of questions for my oncologist appointment coming up and in looking at posts relative to metformin I came across neratinib. I realize the metformin trial ended up demonstrating that it was not beneficial in lessening recurrence rates. But apparently neratinib trials were because it was approved by the FDA in 2017 I think for HER2+ positive patients diagnosed in early stage. Does anyone know if it also helps HER2 low positive in early stage? If so, what are the side effects?

SpecialK

The vast majority of breast cancer drugs start in trials with metastatic patients, where they are studied for a period of time in that population. After noting efficacy, some of these drugs are then extended to the early stage community, where they are studied again - usually more rapidly because the dosing has already been established - and incorporated into the standard of care for early stage. For some of these drugs there are parameters for use such as hormonal receptor arrangement, Her2 status, tumor size/nodal spread, etc. Neratinib is one of those drugs, initially studied and used for metastatic patients, then offered to Her2+ patients who have had chemo and Herceptin, and possibly Perjeta. I have not seen it used for those who are not classified as Her2+, it is not FDA approved for that type of use, nor could I find any trials doing so. It is possible that the I-Spy trials might have been a fit, but I believe that this is for neoadjuvent design so you can't have had surgery yet. Neratinib is currently prescribed to be used after you have completed a year of Herceptin for those who are early stage. I believe the most common side effect is diarrhea, but through experimentation I think they have found that is anti-D meds are taken simultaneously for those with this SE, and/or the dosage is ramped up slowly, it works out - but some have had to discontinue because it can't be controlled.

kaynotrealname

Thanks so much for that information. So as of right now it would probably not be something I could take advantage of. I'll still ask but keep that in mind.

Anonymous

Enhertu is the big breakthrough drug for HER2 low pts, but I think this is also reserved for metastatic BC at the present time