ImmunoGen (NASDAQ: IMGN) ended Monday up 12.5%, after presenting phase 1 data for its anti-CD33 antibody-drug conjugate IMGN779 at the European Hematology Association on Saturday.Like ImmunoGen's other antibody-drug conjugates, IMGN779 delivers a toxic drug payload using an antibody to tumor cells -- in this case, to acute myeloid leukemia cells that express CD33.