Introduction: Treatment of relapsed acute lymphoblastic leukaemia after allogeneic bone marrow transplant can be challenging to clinicians and have a grim prognosis. Relapse sites other than bone marrow are generally central nervous system and gonads. Blinatumomab is a bi-specific T-cell engager(BiTE) antibody that mainly targets leukemic cells CD19 protein. Blinatumomab is effective in relapsed ALL with medullary involvement but in extramedullary relapsed setting its activity is not well-know. Here, we report an effective treatment with blinatumomab in a case of acute lymphoblastic leukaemia that recurred with isolated bone involvement after allogeneic bone marrow transplantation (ABMT).

CASE: A 20-year-old woman diagnosed with a Philadelphia chromosome-negative precursor B cell ALL and remission achieved with HyperCVAD/MA regimen. While in remission after two cycles of HyperCVDAD/MA regimen, 100% compatible sibling donor allogeneic bone marrow transplant was performed. İmmunosupresive therapy continued after six months of a transplant due to chronic GVHD that affects eye and skin. The patient presented with pain in the right elbow three years after the transplant. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging revealed increased signs of FDG uptake in the right radius. There was no recurrence in aspirate and biopsy from the iliac bone marrow. In the biopsy taken from the right radius, leukemic cell infiltration was detected. Blinatumomab therapy was started. No side effects were observed. After two cycles of blinatumomab therapy, pet/ct showed total metabolic response and remission.

Discussion: In acute lymphoblastic leukemia, Blinatumomab therapy may be an effective salvage treatment in patients with extramedullary relapse.

Keywords: Relapsed acute lymphoblastic leukemia, blinatumomab, allogenic bone marrow transplantation.