This appears to be more of an immunotherapy than an actual vaccine as the focus seems to be more on treatment than prevention at this time, and the goal is to stimulate a response 'after' the cancer has started to grow.
I find it interesting that they often will refer to triple-negative breast cancer as a difficult to treat cancer. It does seem that very little conventional treatments are helpful for triple-negative cancer: Tamoxifen or Herceptin are not effective, so the push is for chemotherapy (which isn't really effective) for this aggressive cancer.
I was diagnosed with triple-negative breast cancer, but chose not to do chemotherapy. I chose my own sort of immunotherapy with the help of Dr. James Belanger, a Naturopathic Doctor. A large part of the treatment was mushrooms which have a unique effect on the immune system, and over 5 years later I am still cancer free.
So, for them to say that triple-negative breast cancer is hard to treat is only to say that they don't know of any 'drugs' to fight it. I fought it with my own body, my immune system, eating well and reducing stress.
I am looking forward to hearing more about this - but I still think, if I am going to choose immunotherapy to treat my cancer, I will focus on naturally occurring foods and nutrients, rather than something designed in the lab to attack. I always have that option if the cancer comes back.