Comparable analysis of outcomes for allogeneic peripheral blood stem cell transplantation from matched related and matched unrelated donors in acute myeloid leukemia

Outcome and Prognostic Factors of High-Risk Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Background

Allogeneic transplantation remains one of the best therapies for high-risk acute myeloid leukemia (HR-AML).

Material/Methods

This study retrospectively analyzed 126 patients with HR-AML after allogeneic hematopoietic stem cell transplantation (allo-HCST).

Results

The disease-free survival (DFS) rates of 1 year and 3 years were 58.83% (95%CI: 50.75–68.20%) and 53.09% (95%CI: 44.59–63.22%) respectively. The cumulative relapse rates of 1 year and 3 years were 21.1% (95%CI: 14.4–28.8%) and 25.9% (95%CI: 18.1–34.5%) respectively. The cumulative incidences of III to IV acute graft-versus-host disease (aGVHD) for 100 days was 8.70% (95%CI: 4.6–14.5%). The cumulative rate of extensive chronic graft-versus-host disease (cGVHD) for 1-year was 4.1% (95%CI: 1.5–8.7%). The cumulative transplantation related mortality rate of 1 year and 3 years were 20.1% (95%CI: 13.6–27.6%) and 21.0% (95%CI: 14.3–28.6%) respectively. Univariate analysis revealed that lower overall survival was correlated with age, bacterial or fungal infection, disease status at transplantation, III–IV aGVHD, post-transplantation lymphoproliferative disorders (PTLD), white blood cell engraftment, and extramedullary involvement (P<0.05). The results of multivariate analysis were that the aforementioned factors were also related to lower overall survival except for PTLD (P<0.05). The results of univariate and multivariate analysis were that extramedullary involvement, III–IV aGVHD, and status pre-transplantation influenced DFS (P<0.05). The risk factors for relapse were status pre-transplantation and extramedullary involvement by univariate and multivariate analysis (P<0.05).

Conclusions

HR-AML has inferior prognosis. Our study indicated the necessity of achieving remission status prior to hematopoietic stem cell transplantation, and administration of preventive treatments on high-risk patients after hematopoietic stem cell transplantation. In addition, adequate prevention and treatment of complications are needed.

Immunotherapy in acute myeloid leukemia

Despite the remarkable progress made in some leukemias such as CML and CLL, cytotoxic treatment for AML remains essentially unchanged over the last 4 decades. Several lines of evidence, including the graft versus leukemia effect associated with allogeneic hematopoietic stem cell transplantation (HSCT), suggest that immunotherapy is an active modality in AML. Given the lack of progress for chemotherapy in this disease, many novel immunologic treatment approaches have been explored. The goals of non-transplant-based immune approaches have largely consisted of the stimulation or restoration of endogenous immune responses or the targeting of specific tumor antigens by immune cells. These strategies have been associated with less toxicity than allogeneic HSCT but typically have inferior efficacy. Allogeneic HSCT exploits major and minor histocompatibility differences between the donor and recipient in order to recognize and eradicate malignancy. With the recognition that the immune system itself provides a basis for treating AML, immunotherapy continues to be an attractive modality to exploit in the treatment of this disease.

Comparative study of the efficacy of allogeneic hematopoietic stem cell transplantation from human leukocyte antigen-haploidentical related and unrelated donors in the treatment of leukemia

AIMS

To compare the efficacy of hematopoietic stem cell transplantation (HSCT) from human leukocyte antigen (HLA)-haploidentical related donors (RD) and unrelated donors (URD) in the treatment of leukemia.

METHODS

Ninety-three leukemia patients underwent allogeneic HSCT were divided into two groups: 51 cases of RD-HSCT and 42 cases of URD-HSCT. In the RD-HSCT group, a preconditioning regimen with fludarabine (Flu) + busulfan (Bu) + cytosine arabinoside (Ara-C) was used in 42 patients and total body irradiation (TBI) + Flu + Ara-C was used in the remaining 9.

RESULTS

In the URD-HSCT group, a modified preconditioning regimen with Bu + cyclophosphamide was used in 35 patients, while the other 7 patients underwent treatment with TBI + Flu. After transplantation, the occurrence rate of grade II-IV acute graft-versus-host disease (GVHD) was 46.0 and 51.2% in the two groups. Likewise, the rate of chronic GVHD was 46.0 and 63.4%, respectively. No significant differences in the occurrence of acute and chronic GVHD were detected between the two groups. The differences in early-stage infection rate after transplantation, recurrence rate, 3-year survival rate, and disease-free survival rate between the two groups were not significant.

CONCLUSION

HLA-haploidentical RD-HSCT with enhanced preconditioning and administration of immunosuppressants showed a clinical efficacy similar to that of URD-HSCT against leukemia, without the risk of increased infection and GVHD.

Adoptable strategic approaches to improve outcomes of allogeneic peripheral blood stem cell transplantations from unrelated donors

While previous studies have shown comparable clinical results for related and unrelated bone marrow transplantation (BMT), the transplantation outcomes for related and unrelated peripheral blood stem cell transplantation (PBSCT) may not follow the same pattern due to a higher incidence of graft-versus-host disease (GVHD)-related morbidity and mortality in the case of long-term survival after unrelated PBSCT. Thus, given the higher possibility of an impaired quality of life due to severe GVHD in long-term survivors who receive unrelated PBSCT, the selection of the stem cell source needs to be decided very carefully. In addition, strategic approaches, such as the extended use of immunosuppressant as a GVHD prophylaxis, the use of antithymocyte globulins (ATGs), choosing a younger donor, and optimizing the CD34+ cell dose, need to be adopted to improve the transplantation outcomes by minimizing GVHD-related morbidity and mortality in an unrelated PBSCT setting. This review article provides a comparison of BMT and PBSCT, and related and unrelated PBSCT, plus introduces several adoptable strategies to improve the outcomes of unrelated PBSCT.