Treatment of chronic granulocytic leukemia with chemoradiotherapy and transplantation of marrow from identical twins.

Twelve patients in the chronic phase of Ph1 (Philadelphia)-positive chronic granulocytic leukemia (CGL) received chemoradiotherapy and marrow from their normal, identical twins. All had a complete remission, with disappearance of all Ph1-positive cells. One patient died of pneumonitis while in remission. Three had a cytogenetic relapse 22 to 30 months after grafting; only one of these three entered blast crisis and died. Eight remain in complete remission 21 to 65 months (median, 30) after transplantation. Thus, the Ph1-positive clone can be ablated and blast crisis delayed or prevented. Of 10 patients with CGL who received transplants during the terminal phase, eight died soon after, one is in complete remission 11 months after receiving a second graft, and one remains in complete remission 71 months after transplantation. This experience suggests to us that every patient with CGL and an identical twin should receive a marrow graft, preferably in the chronic phase. On the basis of our results, trials of allogeneic-marrow transplantation for CGL seem justified.