Umbilical Cord Blood Transplantation after Graft Failure from a Previous Hematopoietic Stem Cell Transplantation

Background : Graft failure (GF) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (HCT). In the absence of autologous recovery, a second HCT is necessary to attempt preventing death due to prolonged pancytopenia. Previous studies describing outcomes of second HCT performed after a GF with different types of donor sources report a wide range of overall survival (OS) and transplant related mortality (TRM), however studies including a large number of patients receiving a second transplant with umbilical cord blood as the graft source are scarce. Objective : To describe umbilical cord blood transplants (UCBT) performed after GF following a previous HCT. Study Design : Retrospective registry-based study, using data extracted from Eurocord and the European Society for Blood and Marrow Transplantation (EBMT) databases. The study reports outcomes of 247 umbilical cord blood transplants (UCBT), performed in EBMT transplant centers, after GF following a previous HCT. Data were analyzed separately for patients with malignant (n=141) and non-malignant diseases (n=106). Results : The most frequent HCT that resulted in GF was also UCBT (65.0% and 68.9%), and most GF occurred within 100 days after transplantation (92.3% and 85.9%), for malignant and non-malignant diseases, correspondingly. Median follow-up was 47 for surviving patients with malignant and 38 months for those with non-malignant diseases. We observed a similar cumulative incidence of neutrophil engraftment of 59.1% (95% CI 51.4- 67.9%) and 60.4% (95% CI 51.7- 70.6%), in a median time of 23 and 24 days for malignant and non-malignant diseases, respectively. The 3-year OS was 28.9% (95% CI 21.8- 37.3%) in the malignant disease group and 49.1% (95% CI 39.5- 58.8%) in the non-malignant. In patients with malignancies, TRM was 39.9% (95%CI 32.5 - 49.1%) at 100 days and malignant 57.5% (95%CI 49.4 - 66.8%) at 3 years. In multivariate analyses, none of the characteristics studied were statistically significantly associated with engraftment or overall survival. Conclusion : Although survival for patients requiring a second transplant is not optimal, UCB remains a valid life-saving option for patients with GF.