Autologous (Auto) and Allogeneic (Allo) Stem Cell Transplantation (SCT) for Pateints (pts) with Advanced Chronic Lymphoctic Leukemia (CLL): A Comparative Study.

Background: AlloSCT is a potential curative treatment for pts with advanced CLL but alloSCT is limited by significant acute and chronic treatment related toxicities and the availability of HLA matched donors. AutoSCT is widely used for treatment of acute leukemia and aggressive lymphoma but rarely used for pts with CLL. This retrospective analysis describes the outcomes of 27 patients from our institution who have undergone either autologous or allogenic SCT for treatment of their advanced CLL. We also compare their transplant outcomes.

Patients and methods: Between 08/98 and 07/07, 27 pts (M;22; median age 54.1, range 37–61) with variable RAI-Sawistsky stage CLL at the time of histological diagnosis (RAI I for 14 patients) underwent SCT (10 autoSCT, 17 matched related donors, 3 matched unrelated donors) Fourteen patients (52%) had a normal karyotype, 13q deletion and trisomy 12 occurring in six and four patients respectively. Median disease duration prior to transplant was 41.7 months (range 5–121). The indication for transplant was refractory disease for most patients. Preparative regimens consisted of Cyclophosphamide (Cy) + TBI (6), Fludarabine (Flu)+Cy (6), Rituximab (R) +Cy+TBI (4) R +melphalan + flu (4) and others (7). NCI complete remission (CR) criteria, flow cytometry, cytogenetics and chimerism data, as available, were used to assess response to therapy.

Results: All 27 patients engrafted, with a mean neutrophil engraftment time of 13.5 days (range 9–24). From the group of patients that received allogeneic transplant, eight (47%) developed acute GVHD, with a median time of 18 days after transplant. Seventeen patients (62%) achieved CR on day +100 by marrow morphology, 15 out of 19 by flow cytometry and 13 out of 15 patients had normal chimerism studies. Non relapse mortality (NRM) on day +100 was 14.8% (17.6% for allo, 0% for auto). Estimated actuarial survival at 3 years for all patients was 68% (65% for alloSCT and 72% for the autoSCT group).Disease free survival at 3 years was defined as the percentage of patients who remained in CR 3 years following transplant. DFS was 62% for the whole group (77% for autoSCT and 51% for the patients who received an alloSCT).

Conclusion: In this study, we have demonstrated high remission rate after both autologous and allogeneic SCT, however, the transplant outcomes (day 100 NRM, DFS and OS) favors autologous over allogeneic with toxicity related death accounted for most of the treatment failures after an alloSCT. Our results suggested that AutoSCT warranted further studies, in particular for older patients and those without a suitable donor.