Study of AZD5991 Alone or in Combination With Venetoclax in Relapsed or Refractory Haematologic Malignancies.

AZD5991 will be administered intravenously for 9 cycles (each cycle 21 days) or until patient derives treatment benefit or progresses

Ascending oral doses of AZD5991 and/or venetoclax until no longer tolerated or disease progression