Hi Trish
I am a newly diagnosed TNBC stage 3 just joined. I am 45 and a pharmacist. Happy to talk. I am also be pembro. With stage 4, you will be entitled to a newer drug called trodelvy. If the doc has not mentioned it. Maybe it is worthwhile bringing it up. Hopefully it is of help.
https://www.rarecancers.org.au/news/437/new-pbs-listing-trodelvy-for-the-treatment-of-metastatic-triple-negative-breast-cancer-from-1-may#:~:text=Trodelvy%C2%AE%20(sacituzumab%20govitecan)%20will%20become%20available%20on%20the%20Pharmaceutical,with%20two%20or%20more%20therapies.