Outcomes Following Second Allogeneic Stem Cell Transplant for Graft Failure or Poor Graft Function: A Single Centre Experience.

Graft failure is a rare but life-threatening complication following allogeneic hematopoietic stem cell transplantation (HSCT). We aim to review the outcomes of patients who underwent a second HSCT (HSCT2) for graft failure or poor graft function at our centre. Twenty-one patients were identified between February 2001 and July 2021; 11 with primary and 10 with secondary graft failure. For HSCT2, matched unrelated donor was the most common donor type (33%) and the same donor as the first allotransplant was used in 24%. Most patient received peripheral blood stem cell source (81%) and reduced intensity conditioning (100%). Graft-versus-host-disease (GVHD) prophylaxis was calcineurin inhibitor-based with either methotrexate or mycophenolate mofetil. The median follow-up for survivors was 120 months (range 7-170). Overall survival was 52% at 2 years, and 46% at 5 years. Death before day + 30 occurred in 5 patients (24%). Non-relapse mortality (NRM) was the major cause of treatment failure, with 2-year NRM of 48%. Infectious complications was the most common cause of death. Relapse occurred in 3 patients (14%). All patients who lived beyond day + 30 successfully engrafted, with a median time to neutrophil recovery of 22 days (range 11-31). The incidence of acute GVHD was 50% and chronic GVHD was 50%. Two patients subsequently developed secondary graft failure and both underwent a third allotransplant. Our real-world data confirms that a HSCT2 for graft failure or poor graft function is associated with high NRM and early mortality. Nevertheless, there are long term survivors and further studies should focus on decreasing toxicity.