Patients must not be known to be refractory to red blood cell or platelet transfusions Hemoglobin ? g/dL with no blood transfusions (packed red blood cells and platelet transfusions) in the past days, within days prior to administration of study treatment Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable Whole blood transfusions in the last days prior to entry to the study which may interfere with gBRCA testing (packed red blood cells and platelet transfusions are acceptable) No platelet transfusions within days of registration to meet eligibility criteria; Note: red blood cell transfusions are allowed at any time Transfusions are permitted to meet both the platelet and hemoglobin criteria; patients must not be known to be refractory to red blood cell or platelet transfusions Measured within days prior to registration: hemoglobin >= . g/dL with no blood transfusions (packed red blood cells in the past days is permitted) Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable) Liver MRI (? days prior to initiation of transplant conditioning) to document hepatic iron content is required for participants who are currently receiving ? packed red blood cell transfusions for ? year or have received ? packed red blood cell transfusions (cumulative). Participants who have hepatic iron content ? mg Fe/ g liver dry weight by liver MRI must have a liver biopsy and histological examination/documentation of the absence of cirrhosis, bridging fibrosis and active hepatitis (? days prior to initiation of transplant conditioning). Blood (packed red blood cells, platelets) transfusions within month prior to study start Unable to accept blood product transfusions Use of red blood cell or platelet transfusions within weeks of treatment Within days prior to registration: Hemoglobin >= g/dL; patients may be transfused packed red blood cells (PRBCs) up to week prior to when enrollment labs are drawn; on study, transfusions may be given as clinically indicated Patients who have had a whole blood transfusion within days prior to enrollment. (Packed red blood cells and platelet transfusions are acceptable) Packed red blood cell transfusions or erythropoietin therapy within days prior to the study enrollment unless erythropoietin therapy has been used to maintain a stable condition for at least month prior to the enrollment Whole blood transfusions in the last days prior to entry to the study Hematologic function, as follows (no red blood cell or platelet transfusions are allowed within days of the first dose of enfortumab vedotin): Within two weeks prior to enrollment: Not refractory to red cell or platelet transfusions Patients should not be known to be refractory to red blood cell or platelet transfusions Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable) Patients known to be refractory to platelet or packed red cell transfusions per Institutional Guidelines, or a patient who refuses blood product support. Patients must be willing to accept blood product transfusions Whole blood transfusions in the last days Transfusion independent (no red blood cell or platelet transfusions in the preceding weeks of screening) PHASE I: No blood transfusions days prior to study entry PHASE II: No blood transfusions days prior to study entry Patients refractory to red blood cell or platelet transfusions Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable). Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable) Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable) Anemia that requires red blood cell transfusions Patients in CRi must have evidence of hematologic recovery after prior therapy independent of red blood cell transfusions blood transfusions prior to , Whole blood transfusions in the last days prior to entry to the study (packed red blood cells and platelet transfusions are acceptable. Within days after subjects signed the treatment consent: Hemoglobin >= g/dl; patients may be transfused packed red blood cells (PRBCs) up to week prior to when enrollment labs are drawn; on study, transfusions may be given as clinically indicated Unwilling to accept blood product transfusions Patients refractory to red blood cell or platelet transfusions Subject has received blood transfusions or hematopoietic factor therapy within days prior to the first dose of study drug. Blood transfusions or hemopoietic factor therapy Patients with leukemia must not be known to be refractory to red blood cell or platelet transfusions. Any patient requiring chronic maintenance of red blood cell, white blood cell or granulocyte counts through the use of blood transfusions or growth factor support (e.g. Neulasta, Neupogen) Adequate renal, hepatic, and bone marrow function without frequent blood product or hematopoietic growth factor support (eg use of erythropoietin or transfusions > units packed red blood cells every months) Blood transfusions or hemopoietic factor therapy Platelet count >= X ^/L w/o blood transfusions for days preceding lab assessment, obtained within days prior to PET scan