Stem cell transplantation-harnessing of graft-versus-malignancy

Effect of age on outcome of reduced-intensity hematopoietic cell transplantation for older patients with acute myeloid leukemia in first complete remission or with myelodysplastic syndrome

PURPOSE Acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) primarily afflict older individuals. Hematopoietic cell transplantation (HCT) is generally not offered because of concerns of excess morbidity and mortality. Reduced-intensity conditioning (RIC) regimens allow increased use of allogeneic HCT for older patients. To define prognostic factors impacting long-term outcomes of RIC regimens in patients older than age 40 years with AML in first complete remission or MDS and to determine the impact of age, we analyzed data from the Center for International Blood and Marrow Transplant Research (CIBMTR). PATIENTS AND METHODS We reviewed data reported to the CIBMTR (1995 to 2005) on 1,080 patients undergoing RIC HCT. Outcomes analyzed included neutrophil recovery, incidence of acute or chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse, disease-free survival (DFS), and overall survival (OS). RESULTS Univariate analyses demonstrated no age group differences in NRM, grade 2 to 4 acute GVHD, chronic GVHD, or relapse. Patients age 40 to 54, 55 to 59, 60 to 64, and > or = 65 years had 2-year survival rates as follows: 44% (95% CI, 37% to 52%), 50% (95% CI, 41% to 59%), 34% (95% CI, 25% to 43%), and 36% (95% CI, 24% to 49%), respectively, for patients with AML (P = .06); and 42% (95% CI, 35% to 49%), 35% (95% CI, 27% to 43%), 45% (95% CI, 36% to 54%), and 38% (95% CI, 25% to 51%), respectively, for patients with MDS (P = .37). Multivariate analysis revealed no significant impact of age on NRM, relapse, DFS, or OS (all P > .3). Greater HLA disparity adversely affected 2-year NRM, DFS, and OS. Unfavorable cytogenetics adversely impacted relapse, DFS, and OS. Better pre-HCT performance status predicted improved 2-year OS. CONCLUSION With these similar outcomes observed in older patients, we conclude that older age alone should not be considered a contraindication to HCT.

Donor leukocyte infusions for the treatment of relapsed acute leukemia after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (SCT) offers the only hope for cure for many adults with acute leukemia. Unfortunately, many patients relapse and die of their disease even after transplantation. Although in some cases, allogeneic SCT is effective because the intensive conditioning therapy eradicates all malignant cells, it has long been recognized that the adoptive transfer of donor immunity plays a critically important role in the induction and maintenance of remission. Recognition of the graft-versus-leukemia (GVL) effect of allogeneic SCT has prompted attempts at remission re-induction by adoptive immunotherapy with donor lymphocyte infusions (DLIs) in patients with relapsed disease after allogeneic SCT. In some cases, DLI-induced remissions are sustained and patients cured when no other treatment modality was effective. This review discusses the rationale, biology, complications and future applications of DLI in acute leukemia patients after allogeneic SCT.

Donor leukocyte infusions in myeloid malignancies: new strategies

Donor leukocyte infusion (DLI) provides direct and potent graft-versus-leukemia (GVL) activity to treat relapse after allogeneic stem-cell transplantation. DLI is dramatically effective for relapsed chronic myelogenous leukemia (CML), but has been less effective for relapse of other myeloid malignancies. Nevertheless, most recipients of DLI for relapsed CML, and many patients with relapsed acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), will experience prolonged remissions and probable cure. Graft-versus-host disease remains the major complication of DLI. New strategies for GVL induction explore novel dosing regimens and both methods of enhancing GVL activity of donor T cells and of minimizing toxicity from graft-versus-host disease. Ultimately, the identification of the effector cells and target antigens for GVL induction will lead to the use of tumor-specific adoptive immunotherapy to both prevent and treat relapse with minimal toxicity. Although many issues remain unsettled, the potential to harness the graft-versus-leukemia activity of allogeneic donor cells provides a powerful new paradigm for the immunotherapy of cancer.

Current status of hematopoietic stem cell transplantation after nonmyeloablative conditioning

PURPOSE OF REVIEW

Allogeneic hematopoietic stem cell transplantation was originally developed as a form of rescue from high-dose chemoradiotherapy, which is given both to eradicate malignancy and provide sufficient immunosuppression for allogeneic engraftment. However, it was observed that allogeneic immunocompetent cells transplanted with the stem cells, or arising from them, mediated therapeutic antitumor effects independent of the action of the high-dose therapy. This was termed a graft-versus-tumor effect. This has prompted the recent development of nonmyeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation that have opened the way to include elderly patients and those with comorbid conditions.

RECENT FINDINGS

Recent retrospective studies comparing hematopoietic stem cell transplantation after myeloablative or nonmyeloablative regimens suggested that the use of nonmyeloablative conditioning might be associated with lower transplant-related toxicity, lower nonrelapse mortality, and at least similar intermediate-term progression-free survival.

SUMMARY

Hematopoietic stem cell transplantation after nonmyeloablative conditioning might become the procedure of choice also for younger patients. Phase 3 studies are needed to determine outcomes for different diseases and age groups.

Allogeneic Peripheral Blood Stem Cell Transplantation Using Reduced Intensity Versus Myeloablative Conditioning Regimens for the Treatment of Leukemia

Reduced intensity conditioning (RIC) have allowed the application of transplantation to older patients and to patients with underlying medical problems. Between October, 1999, and June, 2003, 61 patients with acute leukemia or chronic myeloid leukemia received allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT) from HLA-identical siblings. Thirty-four were conditioned with myeloablative protocols and twenty-seven with RIC regimens. The patients in the myeloablative group were younger (29 vs. 37 years; p < 0.0003), most of them were transplanted in complete remission (74% vs. 59%; p < 0.03), had a shorter interval between diagnosis and HSCT (12 vs. 21 months; p < 0.02) and a greater proportion belonged to standard-risk prognosis (68% vs. 48%; p < 0.1). The median times to neutrophil, platelet and red blood cell engraftment for the myeloablative and RIC groups were 14 versus 11 days (p < 0.009), 17 versus 9 days (p < 0.0001), and 19 versus 12 days (p < 0.007), respectively. Transfusion requirements were lower in the RIC group. Severe mucositis was present in 32% and 7%, respectively (p < 0.01). The proportion of patients having acute graft versus-disease (GVHD), chronic GVHD, and infections was the same, as well as early and late mortality, disease-free survival, and overall survival. Analyzing all the patients together, three factors significantly influenced overall survival: standard risk patients, complete remission at transplant, and the absence of severe acute GVHD. In conclusion, our data suggest that even in high-risk patients, RIC transplantation seems to be as useful as ablative HSCT.