Eltrombopag Treatment in Patients With Prolonged BM Toxicity After CART

CAR-T therapy is the standrad of care in patients with relapse/refractory B cell agressive lymphoproliferative diseases. Prolonged cytopenia is a not uncommon side effect and is associated with susbstantial morbidity and in severe cases also with mortality. The pathobiologic process that causes bone marrow injury is not known and in order to find appropriate treatment it is important to expand the knowledge regarding this toxicity. Current treatment options for bone marrow suppression includes growth factor therapy (GCSF), steroids and immunoglobulins. . The investigators hypothesize that CART cells directly suppress or create inflammatory process in bone marrow. This process may resemble aplastic anemia, a marrow aplasia that occurs secondary to inflammatory process. Treatment of aplastic anemia is based on the administration of eltrombopag, that causes a thrombopoietin-mimetic blood cells to develop and multiply. This treatment demonstrated an increase in the amount of platelets and neutrophils in patients with aplastic anemia and is approved by the health authorities around the world and in Israel as a standard treatment for this disease. There are several reports of successful use of altrombopag in patients after CART who have developed marrow toxicity and in patients after bone marrow transplantation whose blood counts are low. In this study, patients with prologed aplasia after CART cells therapy, will be given eltrombopag in a purpose to incrase bone marrow function. In addition, the investigators will perform several assays to shed more light on the basic pathologic process that causes the bone marrow aplasia.