Second Stem Cell Harvest from Unrelated Donors for Patients with Relapse or Graft Failure after First Transplantation: Patient Age >50 Years and Relapse of Malignant Disease Are Associated with Poor Outcome.

Introduction: Hematopoietic progenitor cells from unrelated donors are increasingly used for allogeneic stem cell transplantation (SCT). A second donation of peripheral blood stem cells (PBSC) or bone marrow is widely accepted in case of graft failure of relapse.

Patients and methods: We retrospectively investigated the outcome of seventy (n=70) patients with hematological malignancies (AML/MDS n=29, CML n=19, ALL n=17, other n=5) receiving a second SCT using PBSC (n=67) or bone marrow (n=3) from the same unrelated donors. Patients had a median age of 30 years (range 1–59) and the reason for a second donation of stem cells consisted of either relapse (n=37) or graft failure (n=33). Whereas in 21 patients no conditioning was used in the remaining patients it was busulfan or TBI-based in the majority of cases.

Results: After a median follow-up of 33 months (range 7.9–76.2) after 2^nd SCT a total of 55 patients died due to treatment-related mortality (63%) or relapse (16%) resulting in a median overall survival (OS) for all patients of 3 months. The OS was significantly better in patients < 50 years (38 vs. 8 %, p=0.01) and in case of graft failure (37% vs. 7%, p=0.02). Time interval between SCT, HLA-disparity, disease type (AML/MDS vs. CML vs. ALL), infused CD34+ cells/kg or graft source at first transplant had no impact.

Conclusion: These data show the lack of efficacy of a second infusion of HSC from the same donor especially in older patients and in cases in which relapse of malignancy is the reason for second transplant. Given the currently unknown long-term effects of a repeated exposure to G-CSF, the factors mentioned above should be kept in mind whenever a request for a second HSC donation is considered.