Prognostic factors to predict outcome of reduced intensity allogeneic haematopoietic cell transplantation for chronic lymphocytic leukemia
Abstract
Despite advances in immunochemotherapy CLL remains an incurable disease.. Allogeneic haematopoietic cell transplantation (HCT) has proven curative potential with ability to overcome adverse prognostic factors, however due to its toxicity it is generally perceived as the last option.
We performed retrospective study to explore the outcomes and possible determinants of survival in the unselected consecutive cohort of 68 CLL patients (median age 59 years) receiving reduced intensity HCT as a part of salvage therapy in 2 Czech centers. The median interval from diagnosis to HCT was 69 months with median 3 of prior regimens, all patients were refractory to purine analogues. 49% of patients were transplanted with advanced (i.e. refractory or progressive disease or CR/PR>3), 38% had high risk cytogenetics.
With median follow-up of 35 months the 3-year Kaplan-Meier survival probability for OS and PFS were 39% and 26%, respectively. Altogether 18 patients (26%) have relapsed or progressed.
During the follow-up 41 patients died, 32 (78%) of transplant related factors (NRM), the others of relapse or disease progression. Univariate analysis failed to identify any clinical and pre- or post-transplant variables having clear prognostic significance for OS or PFS.
The marginal OS advantage favoring HCT performed recently was detected (3-year OS: 31% for HCT until 2006 and 47% thereafter, p=0.0923). In multivariable hazards model only the female donors were associated with shorter OS (HR 2.278, p=0.016) whereas transplanted T-cell> 2.75x10(8)/kg predicted inferior PFS(HR 1.957, p=0.035).
No prognostic impact of donor type, age of donor and recipient, HLA mismatch, disease status pre-HCT, number of previous therapy lines, interval from dg. to HCT and number of transplanted hematopoietic cells was found. Our findings support the conclusion that alloHCT is able to overcome well known negative cytogenetic prognostic factors and that preferring male to female donors could be beneficial.