Are backup BM harvests worthwhile in unrelated donor allogeneic transplants?

The Cleveland Clinic blood and marrow transplant program has routinely performed 'backup' autologous harvests in unrelated recipients with hematological malignancies in remission, lymphoma without marrow involvement and CML in chronic phase. We reviewed all adult or cord unrelated donor (URD) transplants performed from January 1995 through September 2008 to evaluate the value of this procedure. Of 130 patients who had backup harvests, 15 (11%) had their backup harvests re-infused, all for graft failure. No patients undergoing fully ablative preparation and unmanipulated or T-depleted grafts from well-matched adult donors required infusion of backup marrow. Nine of 42 patients who underwent T cell grafts from partially matched or mismatched donors, five patients undergoing partially matched ablative transplants from adult donors or cord blood, and one patient undergoing non-myeloablative transplant required infusion of their back-up harvest. Five of 15 patients who received their backup marrow are alive in CR 2-11.6 (median 7.6) years from infusion. Two of these five were bridged to a second URD transplant; the other three showed durable disease-free survival without a second allogeneic transplant. Backup harvest is unnecessary for HLA well-matched myeloablative transplants, but may be useful in patients at higher risk of graft failure.