Autologous stem cell transplantation for patients with acute promyelocytic leukemia in second molecular remission

Relapse still occurs in approximately 20-30% of patients with acute promyelocytic leukemia (APL) and, after achievement of second complete remission (CR), the optimal strategy is still controversial. We describe therapeutic results from a series of 13 patients autografted in second molecular remission (MR) by a molecular negative apheresis product. In all patients, the disease was confirmed at the molecular level and all had received the GIMEMA/AIDA protocol, achieving molecular remission at the end of consolidation. Relapse was hematological in 12 cases and molecular in one. After consolidation with chemotherapy, all patients achieved MR and received a further course plus granulocyte-colony stimulating factor as mobilizing therapy. A median of 7.6×10(6) (range 2.7-10) CD34-positive cells/kg were collected. In all cases, molecular evaluation of the apheresis product was negative for the promyelocytic leukemia/retinoic acid receptor alpha gene. No case of transplant-related mortality was recorded. No maintenance or consolidation therapy after autologous stem cell transplantation (ASCT) was given to any patient. After a median follow-up of 25 months from ASCT, 10 patients are alive in sustained MR, while two relapsed after ASCT and died in the setting of refractory disease; one patient achieved a third CR and is waiting for allogeneic SCT. These results suggest that ASCT performed with a molecularly negative graft in APL patients in second MR offers a valid chance for achieving a cure. Such an approach should also be considered in relapsed patients with an HLA-compatible donor, namely in those with a first CR lasting more than one year or in unfit or elderly individuals.