Gemtuzumab therapy for isolated extramedullary AML relapse following allogeneic stem-cell transplant

Background A 19-year-old male with primary refractory acute myeloid leukemia received salvage therapy with mitoxantrone and cytarabine combination. He received consolidation therapy 3 months later with a matched-unrelated-donor stem-cell transplant. The disease relapsed in the bone marrow (BM) 9 months after the initial stem-cell transplant, and was successfully treated by repeat transplant from the same donor. Ten months following repeat transplant, the patient presented with an increasing number of extramedullary sites of biopsy-proven disease relapse (i.e. cranial and peripheral nerves, tongue, abdominal wall and chest wall). Repeated biopsy of the BM and chimera study showed no morphologic evidence of leukemic infiltrate with 100% donor-cell population. Investigations Physical examination, complete blood count, BM biopsy, flow cytometry, cytogenetic analysis, chimera study, tongue biopsy, abdominal-wall biopsy, cytology and immunohistochemistry, CT scan of the chest, abdomen and pelvis, MRI of the brain, and cerebrospinal fluid analysis. Diagnosis Isolated extramedullary relapse of acute myeloid leukemia after stem-cell transplant. Management Primary leukemia treatment with idarubicin, cytarabine, etoposide, dexamethasone, tioguanine on protocol and salvage therapy with mitoxantrone and cytarabine combination for primary refractory disease. A matched-unrelated-donor stem-cell transplant for consolidation and donor-lymphocyte infusions were performed, followed by repeat unrelated-donor transplant for leukemia relapse in the marrow, radiation therapy and gemtuzumab ozogamicin for multiple sites of extramedullary leukemia relapse.