AMV564 in combination with anti-PD1 antibody also reduced the levels of CD33hi cells in primary MDS specimens both in terms of overall percentage (Fig 4A) and proliferative capacity (Fig 4B)....We therefore conclude that AMV564 is a potent agent that can improve hematopoiesis in MDS ex vivo, and the addition of checkpoint inhibitors further enhance its effects against CD33hi cells in MDS.