Radiation, Mylotarg, and DLI for Extramedullary Relapse from AML Post-Allogeneic Transplant.

Introduction: Extramedullary relapse of acute leukemia after hematopoietic cell transplant often occurs as granulocytic sarcomas or leukemia cutis. There is no standard of care for these patients and their prognosis is poor. We describe three patients with extramedullary relapse who were treated with a combination of radiation, gemtuzumab ozogamicin and DLI (donor leukocyte infusion).

Methods: All three patients had a diagnosis of AML, underwent induction and consolidation therapy, and then received a myeloablative TBI-based allogeneic transplant. Two patients presented with chloromas and one presented with leukemia cutis as sites of recurrence. None had evidence of bone marrow recurrence, and relapse occurred from 4 – 11 months post transplant. All three were treated with radiation therapy to the site of relapse followed by gemtuzumab ozogamicin and DLI. The radiation doses were 20 – 30 Gy, followed by gemtuzumab ozogamicin 9 mg/m2 given every two weeks for two doses. All three patients received DLI initially at 1.0 x 10-7 CD3+ cells/kg, and subsequently dose-escalated to 2.0 x 10-7.

Results: All three patients achieved complete remission. Median disease free survival has not been reached with a median follow-up of 8 months. One patient with leukemia cutis died from GVHD nine months after the first dose of DLI. The remaining two patients are alive, disease-free, and have no evidence of GVHD.

Conclusion: The combination of radiation, gemtuzumab ozogamicin, and immunotherapy with DLI may offer survival to patients who relapse with AML after allogeneic transplant.