I have no idea how old the mice were, and I mean this seriously too.
What I do know is that the mice were FIRST infected and treated, THEN CURED, THEN reinfected and NOT TREATED and THEN OBSERVED TO NOT CONTRACT the disease, THEN ALL 100% of them died from OLD AGE and not from a new tumour.
That is as far as the presentation of Brekken went + all published material up to today and were FACT ends.
However the man was quite emotional (well Brekken-grade emotional that is a kind of non-contained enthusiasm with a dressing of hyper dynamic expressions) when he talked about it. And, but that is IMPRESSION, I was under the impression that mice usually in such experiments do not die of old age, the old age being overly emphasized with a touch of miracle-witnessing astonishment.
Now Dr. Stopeck has been seeing the same things in Breast IST (it will be in her paper) and that was on humans that got Bavituximab. And Either Hutchins or Yopp has been seeing the same thing in their Lung or Liver clinical trials (I know suddenly can't remember which of both it was again - Jet Lagged to death :).
I am sure we will hear more of this.