Impact of Comorbidity Index on Outcome with Allogeneic Hematopoetic Stem Cell Transplantation for Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia, a disease that is not curable with standard therapy, is an attractive target for allogeneic (allo) hematopoetic stem cell transplant (HSCT) with demonstrated strong graft vs. leukemia effect. However, optimal selection of patients (pts) in order to maximize outcome and minimize toxicity is still under study. We hypothesized that patient co morbidity, as measured by the HSCT adapted Charlson co morbidity index (CCI) would have a strong effect in this group of patients with older median age. At the Leukemia/BMT Program of BC the CCI has been prospectively calculated for HSCT pts since 2006, and we performed chart review to calculate scores retrospectively for the remaining CLL allo HSCT patients in order to evaluate the impact of this factor on outcome following allo HSCT. Transplant specific data was collected prospectively and entered into an electronic database. Forty pts with CLL proceeded to allo HSCT between Jan 91 and Dec 07, with myeloablative (MA) (n=21) or non-myeloablative/reduced-intensity (NMA/RIC) (n=12/7) conditioning regimen. Median (range) number of prior therapies was 4 (1–7). Twenty-four pts were refractory to fludarabine. Donors were related in 25 cases, unrelated in 15. Median age (range) was 49 yrs (32–57) (MA) and 57 yrs (52–64) (NMA/RIC), with 3 and 13 patients greater than age 55 in the 2 groups respectively. Interval from dx to HSCT was 60 months (range 7–135) (MA) and 90 months (range 18–350) (NMA/RIC). Five yr OS is 55% for the whole group; 51% for the MA group at a median follow-up (med FU) of 7.2 yrs (range 2.8–14.6) and 62% for the NMA/RIC group with med FU of 4.2 yrs (range 0.1–6.8). OS did not differ between the 2 groups (p=0.56). Related and unrelated donors had similar 5yr OS at 60.6 vs. 47.1%, p=0.23. Cumulative incidence of non-relapse mortality at 100 days and 2 years is 10 and 32% for the whole group, 14 and 38% for the MA and 6 and 26% for the NMA/RIC groups. CCI was 0, 1, 2, and 3 or greater for 21, 5, 7, and 7 patients. OS by CCI 0–2 vs. >=3 was 63 vs.18% for the whole group (p=0.01), 56 vs. 0% for the MA (p=0.03), and 74 vs. 27% for the NMA/RIC groups (p=0.06). Further analyses will explore the relationship between CCI and NRM, acute and chronic graft vs. host disease, and relapse. Patient numbers in this series are insufficient to evaluate the impact of specific co morbidities. In conclusion, for patients with CLL, who are in general of older age, and who may have other therapeutic options, allo SCT is optimally performed in those with a low co morbidity score. Patients with a CCI of 3 or greater may be preferential candidates for alternate less toxic therapies.