Analysis of outcomes in patients (pts) with relapsed/refractory acute promyelocytic leukemia (APL) treated with and without high-dose chemotherapy and hematopoietic stem cell transplantation (HCT).

6608 Background: Outcomes of pts with APL have dramatically improved, especially with availability of all-trans retinoic acid (ATRA), arsenic trioxide, and better supportive care. However, a small but significant number of pts relapse despite optimal upfront therapy. Methods: We reviewed pts with APL treated at our institution (1980-2010). Outcome of pts who received autologous (auto) or allogeneic (allo) HCT for relapsed disease was compared with those who did not. Results: We identified 42 pts with relapsed/refractory APL. 25 (60%) pts received auto (8) or allo HCT (17: related 5, unrelated 12). Median (med) age of pts receiving HCT: 29 years (range 6-61). RT-PCR was negative for PML/RARα at time of HCT in 6 of 6 evaluable auto pts and in 6 of 8 evaluable allo pts. Of the 8 auto pts, 5 were in CR2 and 3 in ≥ CR3. Preparative (prep) regimen: Busulfan (Bu) + Cyclophosphamide (CY) in 7 pts and Bu + Fludarabine (Flu) in 1 pt. Of the 17 allo pts, 12 were in CR2 and 5 in ≥CR3. Prep regimens for allo HCT: Bu +...