Second marrow transplants in patients with leukemia who relapse after allogeneic marrow transplantation.

Twenty-six patients with recurrent leukemia following allogeneic marrow transplantation received a second marrow transplant between 1.5 and 78 months (median 26) after the initial transplant. Preparative regimens for second transplant included multi-agent chemotherapy with total body irradiation, 2.0-10.0 Gy (five patients), dimethylbusulfan alone (one patient), and dimethylbusulfan or busulfan plus cyclophosphamide (20 patients). One patient died before engraftment of infection and 18 died after engraftment from veno-occlusive disease (4), infection (2), idiopathic pneumonia (3), cytomegalovirus pneumonia (3), leukemia (5) and encephalopathy (1). Seven patients (27%) survive 12-38 months (median 26); five (19%) are disease-free and two have recurrent leukemia. Two of the five disease-free survivors have chronic graft-versus-host disease. All of the surviving patients received dimethylbusulfan or busulfan plus cyclophosphamide and six of the seven surviving patients were among 11 patients transplanted more than 2 years after the first transplant whereas only one was among the 15 transplanted in less than 2 years. Those who have second marrow transplants one or more years after their initial transplant are more likely to benefit, while those who are less than 1 year from initial transplant appear to benefit the least.