American Trial Using Tranexamic Acid in Thrombocytopenia

Inclusion criteria (all must be met): * Must be ≥ 18 years of age * Confirmed diagnosis of a hematologic malignancy or aplasia * Undergoing or planned chemotherapy, immunotherapy, or hematopoietic stem cell transplantation * Anticipated to have hypoproliferative thrombocytopenia resulting in a platelet count of ≤ 10,000/microliters for ≥ 5 days * Able to provide informed consent and comply with treatment and monitoring, or having a Legally Authorized Representative (LAR) Exclusion criteria (none can be present): * Diagnosis of acute promyelocytic leukemia undergoing induction chemotherapy * History of ITP, TTP or HUS * Subjects receiving L-asparaginase as part of their current cycle of treatment * Subjects with a past history or current diagnosis of arterial or venous thromboembolic disease including acute coronary syndrome, peripheral vascular disease and retinal arterial or venous thrombosis (except when a prior history of central line thrombosis has resolved) * Subjects with a diagnosis/previous history of sinusoidal obstruction syndrome (also called veno-occlusive disease) * Subjects receiving any pro-coagulant agents (e.g. DDAVP, recombinant Factor VIIa or Prothrombin Complex Concentrates (PCC) and/or an antifibrinolytic agent within 48 hours of enrollment, or with known hypercoagulable state * Known inherited or acquired bleeding disorder including, but not limited to: * Acquired storage pool deficiency * Paraproteinemia with platelet inhibition * Known inherited or acquired prothrombotic disorders, including antiphospholipid syndrome. Those with lupus anticoagulant or positive antiphospholipid serology without thrombosis are not excluded. * Subjects receiving anticoagulant therapy or anti-platelet therapy (except when receiving prophylactic anticoagulant or low dose aspirin therapy for prophylaxis only with a plan to discontinue when the platelet count falls below 50,000) * Patients with DIC according to the patient's physician * Subjects with WHO Grade 2 bleeding or greater within 48 hours prior to activation * Subjects requiring a platelet transfusion threshold \> 10,000/microliters at time of randomization * Subjects with anuria (defined as urine output \< 10mls/hr over 24 hours) * Subjects on dialysis * Subjects with creatinine ≥5.7mg/dL * Subjects who are pregnant or nursing or unwilling to use contraception during and for 30 days after taking the study drug (both males and females) * Subjects enrolled in other trials involving platelet transfusions, anti-fibrinolytics, platelet growth factors or other pro-coagulant agents. * Known allergy to tranexamic acid * Having been previously randomized in this study at any stage of their treatment * Subjects who are unwilling to accept blood or blood component transfusions