here is the AACR policy regarding late breaking abstracts:
Late-breaking abstract submissions are no longer being accepted for the AACR Annual Meeting 2012. The late-breaking abstract submission deadline was Thursday, January 26, at 2:00 p.m. US Eastern Time. A special subcommittee of the Program Committee will evaluate the merit of late-breaking abstracts. Only those abstracts that are deemed to be of high scientific priority will be accepted.
You betQ ASCO will not even consider Phase 2 data for late-breaking talks. AACR does, but only in exceptional cases. This is one such case, and I bet that the AACR is loving the fact that they got to stick it to ASCO in this case.