Pembrolizumab has been around for a few years, but is fairly new in the world of TNBC. My oncologist doesn’t have direct personal experience of it, as she is a breast cancer oncologist, and by the sound of it I will be the hospital’s first BC patient to have it. She wasn’t wholly on top of it when I met her yesterday. I went into the meeting knowing its mechanism of action is to disarm the ability of PD-1 and PD-L1 to bind together to hide the cancer from the immune system, and that the drug would therefore also remove the protection my endocrine system has from auto immune damage. She couldn’t answer questions on what the real world experience of this had been.
I have mentioned before that my niece is a doctor, and I am fortunate that she has a wide range of contacts. One of her contacts is an oncologist working in a large city hospital elsewhere in the UK, who has specialised in immunotherapy. She has had about 6 year’s experience of putting patients with lung cancer and melanoma on Pembrolizumab, and has been involved in some of the research programmes. My niece arranged a call for me with her today, which was hugely helpful to my decision making.
She has found that most patients tolerate it well, and that most of the headline endocrine related issues are not common and can usually be treated. She told me there usually aren’t any side effects to start with, as it takes time to work. Whether it works or not is a binary thing - it either does or it doesn’t, there isn’t middle ground, and you can’t tell who it will work for (beyond the caveat that you have to pass the ‘combined score’ test’s 10% PD-L1 threshold (which I have), for it to stand a chance). It seems less effective on TNBC than on some of the other cancers it is authorised for because of the level of immune system cells within the tumour. She also told me it works best when you have a low tumour burden, as I have, with just 2 mets.
Whilst the odds might be low, I am quite excited to give this one a whirl. She also explained the interaction with Paclitaxel and got me comfortable with having more of that.
I have got a short holiday next week and when I return, will sign the consent forms (assuming I have cleared the health screening steps) and get cracking. She warned me that the first scan is likely to show apparent tumour growth, even if the Pembrolizumab is working. This is because the immune system around the tumour gets fired up and starts infiltrating so you initially appear to have a larger mass.
In this situation it always helps to have some hope to hang onto, and I now have some
