Marrow transplantation for acute leukemia.

Marrow transplantation enables the physician to ignore the complications of marrow toxicity which limit the chemotherapy of leukemia and makes it possible to explore new drugs and regimens. The results of marrow transplantation for 154 cases of end-stage acute leukemia carried out by the Seattle Marrow Transplant Team are summarized. Even with the use of an HLA matched sibling as a donor, allogeneic marrow transplantation is followed by graft-versus-host disease in about 2/3 of the patients which is of life-threatening severity in approximately 20%. An actuarial plot of the recurrence rate of leukemia following transplantation shows that about 2/3 of the recipients of either allogeneic or syngeneic (identical twin) marrow will relapse within 2 years. However, about 1/3 will not relapse and recurrence of leukemia has not been observed after 2 years. A Kaplan-Meier plot of the survival of 29 syngeneic marrow recipients and 110 recipients of allogeneic marrow shows an almost flat survival curve in the period f om 2 to 7 years after transplantation. The leukemia free survival of these patients on no maintenance chemotherapy constitutes an operational definition of cure in these patients.