Efficacy of Performing a Second Non-Myeloablative Allogenic Stem Cell Transplant.

Introduction: Non-myeloablative stem cell transplants are being performed for a variety of benign and malignant hematologic conditions. The reported graft failure rates have been as high as 20%. Little is reported on the safety and efficacy of a second attempt at a nonmyeloablative allogeneic transplant.

Methods: Patients who underwent at least 2 nonmyeloablative allogenic transplants at either Duke University or Dana Farber Cancer Centers were included.

Results: 9 patients were identified who underwent at least 2 preparatory regimens with stem cell infusion. 7 patients underwent related donor stem cell infusions and 2 patients had an umbilical cord donor. 4 patients, including the 2 with an umbilical cord donor, had primary graft failure. The remaining had secondary graft failure within 1–9 months from viral disease/therapy or disease progression. 5 of 9 received a 5 day regimen of fludarabine 125mg/m2, campath100mg and cyclophosphomide 2 gm/m2 total for a secondary preparatory regimen (FCC). Two patients received a one-day prep with fludarabine 30mg/m2, 200cGyTBI, cyclophosphamide 2gm/m2 and campath 20mg (FCC/TBI). The two umbilical cord patients received a one day prep that included TBI, cyclophosphamide 500mg/m2, fludarabine 30 mg/m2, and campath 30 mg (FCC/One). One patient with refractory CML failed to engraft, though 8/9 did (1 required a 3rd attempt), including 4 patients who had the same donor as their first transplant. Long-term follow-up revealed the graft was intact in 5 patients at 6, 7, 8, 21, 39, and 63 months. Three patients died.

Conclusion: Patients who have graft failure can be transplanted with a second nonmyeloablative allotransplant. Response and long-term engraftment is possible, even using the same donor.