Second allogeneic peripheral blood stem cell transplants with reduced-intensity conditioning.

Area of Science:

• Hematology
• Transplantation immunology

Background:

• Allogeneic stem cell transplantation is a curative option for various hematologic conditions.
• Relapse and graft failure remain significant challenges after initial hematopoietic stem cell transplantation.
• Exploring salvage strategies like a second transplant is crucial for improving patient outcomes.

Purpose of the Study:

• To evaluate the efficacy and safety of a second allogeneic stem cell transplantation in patients who relapsed or failed engraftment after a first transplant.
• To assess the outcomes of a non-myeloablative preparative regimen in the context of a second transplant.

Main Methods:

• A retrospective analysis of twelve patients undergoing a second allogeneic stem cell transplantation at two institutions in Mexico.
• Utilizing a specific "Mexican" non-myeloablative preparative regimen.
• Tracking engraftment, survival, disease status, and complications post-second transplant.

Main Results:

• Five patients who failed initial engraftment also failed the second transplant, particularly those heavily transfused.
• Three patients achieved successful engraftment and rescue, including two with acute leukemia and one with aplastic anemia.
• Overall survival at 52 months was 58%, with a median survival exceeding 52 months, though only 25% remained disease-free.

Conclusions:

• A second allogeneic stem cell transplant can be a viable rescue option for selected patients relapsing after a first transplant.
• Engraftment failure after the first transplant predicts similar failure in a second attempt, especially in heavily transfused individuals.
• Careful patient selection is essential for optimizing outcomes in second hematopoietic stem cell transplantation.