Outcomes of patients after mobilization failure of hematopoietic stem cells for autologous stem cell transplantation.

Introduction: Autologous hematopoietic stem cell transplantation (ASCT) is the long-term consolidation treatment for various hematological malignancies. The collection of hematopoietic stem cell yield is critical to successful ASCTs, but not always achieved due to hematopoietic stem cell mobilization failure (HSCMF). Details regarding the cell collection and outcomes of those who fail mobilization are still lacking. Therefore, this study aimed to yield data on clinical outcomes and cellular products after HSCMF.

Methods: Retrospective, unicentric study assessing clinical outcomes and characteristics of collected progenitor cells. The data were collected from patient databases. The results were reported in median, rates and percentages and absolute values. Patients older than 18 years of age at the time of mobilization and HSCMF were included.

Results: Five hundred ninety-nine patients underwent mobilization protocols. Thirty-five (5.8%) of them failed in the mobilization and fourteen (40%) died. Median time to death was eight months. Disease progression and infection were responsible for all deaths. Median relapse-free survival was 6.5 months (20 patients, 57%). Seven (20%) survivors were receiving salvage therapy and five (14%) were being followed clinically. Six (20.6%) participants underwent collection by apheresis, with insufficient cell collection. The median quantity of peripheral CD34+ cells in those patients was 10.5/mm. The median CD34+ quantity collected was 0.86 × 10 CD34+ cells/kg.

Conclusions: The mobilization failure was associated with limited survival. Nonetheless, collected products offered perspectives for ex vivo expansion. Further studies should investigate the feasibility of expanding collected CD34+ cells to use as grafts for ASCT.