Should we T cell deplete sibling grafts for acute myeloid leukaemia in first remission?

Sensitivity of hematological malignancies to graft-versus-host effects: an EBMT megafile analysis

After allogeneic stem cell transplantation, graft-versus-host disease (GvHD) occurs through recognition of histocompatibility mismatches by donor T lymphocytes. The same mechanism operates in eliminating malignant cells (the graft-versus-tumor or GvT effect). We hypothesized that comparing the correlation between GvHD and relapse might provide a surrogate marker for the susceptibility of diseases to allo-immune effects. We studied 48 111 first allogeneic transplants performed between 1998 and 2007. In chronic myeloid leukemia (CML), the relapse risk declined clearly and proportionally to severity of acute and chronic GvHD. Acute lymphoblastic leukemia and BCR-ABL-negative myeloproliferative neoplasias were comparably sensitive to GvHD as CML, whereas myelodysplastic syndromes and lymphoproliferative disorders showed intermediate sensitivity. GvHD was only associated with modest reductions in relapse risk in acute myeloid leukemia (AML) and plasma cell disorders (PCDs). Except for PCD, hazard rates for relapse decreased to almost 0 at 48 months of follow-up in all diseases. These data confirm observations of potent GvT effects associated with GvHD. The strength of the GvHD/GvT correlation differs significantly between hematological malignancies. The parallel drop of relapse rates in different diseases despite differences in GvHD/GvT ratios suggests that GvT effects might operate in the absence of GvHD, particularly in AML.

Fludarabine-melphalan conditioning for AML and MDS: alemtuzumab reduces acute and chronic GVHD without affecting long-term outcomes

The purpose of this study was to determine the effect of alemtuzumab on treatment-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DSF) in patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS) undergoing reduced intensity conditioning (RIC). We compared the outcome of 95 patients treated at the University of Chicago with fludarabine melphalan (Flu + Mel) + alemtuzumab conditioning and 59 patients treated at the M.D. Anderson Cancer Center with Flu + Mel conditioning. Both groups had similar patient and donor characteristics. There were no significant differences in TRM, relapse, survival, and DFS between the 2 groups. The incidence of acute graft-versus-host disease (aGVHD) grade II-IV (relative risk [RR] 5.5, P < .01) and chronic GVHD (cGVHD) (RR 6.6, P < .01) were significantly lower in patients receiving alemtuzumab. The addition of alemtuzumab to an RIC regimen dramatically reduces the incidence of aGVHD and cGVHD in patients with AML and MDS undergoing allogeneic transplantation. TRM, relapse risk, OS and DFS are not affected.

Fludarabine, melphalan, and alemtuzumab conditioning in adults with standard-risk advanced acute myeloid leukemia and myelodysplastic syndrome

PURPOSE

This prospective phase II study evaluated toxicity, relapse rate, progression-free survival, and overall survival after allogeneic transplantation and conditioning with fludarabine, melphalan, and alemtuzumab in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

PATIENTS AND METHODS

Fifty-two consecutive adults with AML and MDS were enrolled onto the study. Median age was 52 years (range, 17 to 71 years) and the majority of patients had high-risk disease, comorbidities, and/or modest reduction in performance status. Fifty-six percent of patients had unrelated or mismatched related donors.

RESULTS

After a median follow-up of 18 months (range, 2 to 34 months), 1-year survival was 48% (95% CI, 34% to 61%), progression-free survival was 38% (95% CI, 25% to 52%), relapse rate was 27% (95% CI, 15% to 40%), and treatment-related mortality was 33% (95% CI, 20% to 46%). The cumulative probability of extensive chronic graft-versus-host disease (GVHD) was only 18% (95% CI, 8% to 40%); extensive chronic GVHD was only observed in recipients of unrelated donor transplants. Performance score and disease status were the major predictors of outcome. High-risk disease (ie, active AML or MDS with > 5% blasts) or even modest decreases in performance status were associated with poor outcomes. Patients with standard-risk leukemia (first or second complete remission) or MDS (< 5% blasts) had excellent outcomes despite unfavorable disease characteristics.

CONCLUSION

Fludarabine and melphalan combined with in vivo alemtuzumab is a promising transplantation regimen for patients with AML or MDS and low tumor burden. For patients with active disease, this regimen provides at best modest palliation. Despite a low incidence of GVHD, transplantation is still associated with considerable nonrelapse mortality in patients with decreased performance status.