[Thiotepa-busulfan-fludarabine conditioning in allogeneic hematopoietic stem cell transplantation for blast-phase...

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative option for blast-phase myeloproliferative neoplasms (BP-MPN), although relapse rates remain high. Recently, conditioning with thiotepa, busulfan, and fludarabine (TBF) has shown promising anti-leukemic activity in acute myeloid leukemia.

A 64-year-old man with essential thrombocythemia that progressed to secondary myelofibrosis and subsequently BP-MPN underwent allo-HSCT after cytoreduction with azacitidine plus venetoclax. Peripheral blood stem cells were obtained from an HLA allele-matched unrelated donor, and TBF was used as the conditioning regimen. Low-dose anti-thymocyte globulin was administered for graft-versus-host disease (GVHD) prophylaxis. Full donor chimerism was achieved on day 28 after transplantation. Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) improved with defibrotide, and acute GVHD was manageable.

This case suggests that a multidisciplinary treatment strategy incorporating TBF conditioning may improve relapse-free survival in patients with BP-MPN.