Long-term disease-free survival after nonmyeloablative cyclophosphamide/fludarabine conditioning and related/unrelated allotransplantation for acute myeloid leukemia/myelodysplasia

Costo efectividad de las pruebas para estratificar riesgo en el tratamiento de la leucemia mieloide aguda (LMA) en población pediátrica

Objetivo Estimar la razón de costo-efectividad de las pruebas para estratificación del riesgo en pacientes pediátricos con Leucemia Mieloide Aguda (LMA).Métodos Se construyó un árbol de decisión con años de vida ganados como medida de efectividad. Los costos fueron estimados desde la perspectiva del sistema de salud colombiano. En los costos de la estratificación se incluyeron los costos del tratamiento consecuente con ella. Los precios de medicamentos fueron tomados del SISMED 2008 y el valor monetario de los procedimientos se extrajo del manual tarifario del ISS 2001 adicionando el 30 %. Todos los costos se expresaron en pesos colombianos del 2010 y el producto interno per-cápita de ese año fue empleado como umbral de costo efectividad. Se condujeron análisis de sensibilidad univariados y probabilísticos.Resultados La razón de costo-efectividad incremental de las pruebas de estratificación a todos los pacientes, fue de $8 559 944. Los resultados son sensibles a las probabilidades de recaída, supervivencia al trasplante y efectos secundarios.Conclusión Las pruebas para estratificación del riesgo en LMA son costo-efectivas dentro del sistema de salud colombiano.

Reduced-intensity conditioning allogeneic hematopoietic-cell transplantation for older patients with acute myeloid leukemia

Elderly patients (>60 years) with acute myeloid leukemia have a poor prognosis with a chemotherapy-alone approach. Allogeneic hematopoietic-cell transplantation (HCT) can improve overall survival (OS). However, myeloablative regimens can have unacceptably high transplant-related mortality (TRM) in an unselected group of older patients. Reduced-intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning regimens preserve the graft-versus-leukemia effects but reduce TRM. NMA regimens result in minimal cytopenia and may not require stem cell support for restoring hematopoiesis. RIC regimens, intermediate in intensity between NMA and myeloablative regimens, can cause prolonged myelosuppresion and usually require stem cell support. A few retrospective and prospective studies suggest a possibility of lower risk of relapse with myeloablative HCT in fit older patients with lower HCT comorbidity index; however, RIC and NMA HCTs have an important role in less-fit patients and those with significant comorbidities because of lower TRM. Whether early tapering of immunosuppression, monitoring of minimal residual disease, and post-transplant maintenance therapy can improve the outcomes of RIC and NMA HCT in elderly patients will require prospective trials.

Long-term follow-up of the AML97 study for patients aged 60 years and above with acute myeloid leukaemia: a study of the East German Haematology and Oncology Study Group (OSHO)

INTRODUCTION

Treatment of patients (pts) with acute myelogenous leukaemia (AML) above 60 years remains a challenge. We report long-term follow-up of the AML97 study, where pts were registered at diagnosis and received treatment dependent on their comorbidities: dose-intense cytarabine (AraC) and anthracycline in the curative arm, and low-dose chemotherapy in the palliative arm or best supportive care.

MATERIALS AND METHODS

A total of 618 pts were enrolled in this protocol (curative 471, palliative 115 and supportive 32). In the curative arm, complete remission (CR) was obtained in 66.8 % of pts and the estimated probability of being alive at 2 years was 0.30 (±0.02 SE). In multivariate analysis, gender (p = 0.005), performance status (p = 0.04) and cytogenetics (p = 0.002) were significant factors for CR. With a median follow-up of 10 (range 0.1-11.8) years, the estimated probability of being event-free after 2 and 5 years according to cytogenetics was 0.48 ± 0.11 and 0.48 ± 0.11 for favourable, 0.20 ± 0.03 and 0.09 ± 0.03 for normal, 0.18 ± 0.06 and 0.10 ± 0.05 for other standard risk and 0.10 ± 0.03 and 0.05 ± 0.02 for unfavourable karyotypes, respectively. The median survival time for pts treated with palliative chemotherapy was 54 and 11 days with best supportive care only.

CONCLUSION

In conclusion, treatment of older AML pts with dose-intense AraC is feasible in the majority of pts and induces high rates of CR. Nevertheless, except for favourable karyotype, OS and event-free survival remain low. These results need to be viewed in relation to the new modalities including stem cell transplantation following non-myeloablative conditioning, epigenetic and molecular therapies.

Cyclophosphamide/fludarabine nonmyeloablative allotransplant for acute myeloid leukemia

We compared survival outcomes following myeloablative allotransplant (MAT) or cyclophosphamide/fludarabine (Cy/Flu) nonmyeloablative allotransplant (NMAT) for 165 patients with acute myelogenous leukemia (AML) in remission or without frank relapse. Patients who received NMAT were more likely to be older and have secondary AML and lower performance status. At a median follow-up of 61 months, median event-free survival and overall survival survival were not different between NMAT and MAT in univariate as well as multivariate analyses. Cy/Flu NMAT may provide similar disease control and survival when compared with MAT in patients with AML in remission or without frank relapse.

Prognostic biomarkers for acute graft-versus-host disease risk after cyclophosphamide-fludarabine nonmyeloablative allotransplantation

Five candidate plasma biomarkers (suppression of tumorogenesis 2 [ST2], regenerating islet-derived-3α [REG3α], elafin, tumor necrosis factor receptor 1 [TNFR1], and soluble IL-2 receptor-alpha [sIL2Rα]) were measured at specific time points after cyclophosphamide/fludarabine-based nonmyeloablative allotransplantation (NMAT) in patients who did or did not develop acute graft-versus-host disease (aGVHD). Plasma samples from 34 patients were analyzed at days +7, +14, +21, and +30. At a median follow-up of 358 days, 17 patients had experienced aGVHD with a median time to onset at day +36. Risk of aGVHD was associated with elevated plasma ST2 concentrations at day +7 (c-statistic = .72, P = .03), day +14 (c-statistic = .74, P = .02), and day +21 (c-statistic = .75, P = .02); elevated plasma REG3α concentrations at day +14 (c-statistic = .73, P = .03), day +21 (c-statistic = .76, P = .01), and day +30 (c-statistic = .73, P = .03); and elevated elafin at day +14 (c-statistic = .71, P = .04). Plasma concentrations of TNFR1 and sIL2Rα were not associated with aGVHD risk at any of the time points studied. This study identified ST2, REG3α, and elafin as prognostic biomarkers to evaluate risk of aGVHD after cyclophosphamide/fludarabine-based NMAT. These results need to be confirmed in an independent validation cohort.

Comparison of minimal residual disease as outcome predictor for AML patients in first complete remission undergoing myeloablative or nonmyeloablative allogeneic hematopoietic cell transplantation

Minimal residual disease (MRD) is associated with adverse outcome in AML after myeloablative (MA) hematopoietic cell transplantation (HCT). We compared this association with that seen after nonmyeloablative (NMA) conditioning in 241 adults receiving NMA (n=86) or MA (n=155) HCT for AML in first remission with pre-HCT bone marrow aspirates assessed by flow cytometry. NMA patients were older and had more comorbidities and secondary leukemias. Three-year relapse estimates were 28% and 57% for MRD^neg and MRD^pos NMA patients, and 22% and 63% for MA patients. Three-year overall survival (OS) estimates were 48% and 41% for MRD^neg and MRD^pos NMA patients and 76% and 25% for MA patients. This similar OS after NMA conditioning was largely accounted for by higher non-relapse mortality (NRM) in MRD^neg (30%) compared to MRD^pos (10%) patients, whereas the reverse was found for MRD^neg (7%) and MRD^pos (23%) MA patients. A statistically significant difference between MA and NMA patients in the association of MRD with OS (P<0.001) and NRM (P=0.002) but not relapse (P=0.17) was confirmed. After adjustment, the risk of relapse was 4.51-times (P<0.001) higher for MRD^pos patients. These data indicate that the negative impact of MRD on relapse risk is similar after NMA and MA conditioning.

Long-term survival with low toxicity after allogeneic transplantation for acute myeloid leukaemia and myelodysplasia using non-myeloablative conditioning without T cell depletion

The toxicity burden and long-term anti-leukaemic effect of non-myeloablative (NMA) allogeneic haematopoietic stem-cell transplantation (AHSCT) for acute myeloid leukaemia (AML) and myelodysplasia (MDS) remains undefined. We report the outcome of 56 patients with AML/MDS transplanted from human leucocyte antigen-matched donors using NMA conditioning without T-cell depletion. With a median follow-up of 5 years, treatment-related mortality was 9% and current disease-free survival (CDFS) was 45% (overall) and 55% (patients transplanted in remission). Development of graft-versus-host disease upon withdrawal of post-transplant immunosuppression was associated with less relapse and better CDFS. These data confirm that NMA AHSCT without T-cell depletion is safe and can result in sustained remissions of AML/MDS.

Reduced-intensity allografting in patients with therapy-related myeloid neoplasms and active primary malignancies

Therapy-related myeloid neoplasms (t-MNs) are severe long-term consequences of cytotoxic treatments for a primary, often, malignant disorder. So far, the majority of patients eligible for transplantation have undergone myeloablative allo haematopoietic SCT (HSCT) as a potentially curative treatment, but it has been associated with high transplantation-related mortality (TRM) rates. In this retrospective study, we analysed the outcome of patients with t-MNs undergoing HSCT with reduced-intensity conditioning (RIC). Of 55 patients, seen at a single centre over a 10-year period, 17 underwent RIC HSCT with related or unrelated donors. The estimated overall survival was 53% at 1 year and 47% at 3 years, and disease-free survival was 47% at 1 year. At 1 year, the cumulative incidence of relapse and TRM were 24% and 30%, respectively. Of five patients with active primary neoplasms who underwent transplantation, two are alive beyond 1 year and show CR of both t-MNs and the primary malignancy. These data indicate that RIC HSCT is an encouraging approach for patients with t-MNs. The issue of primary malignancies not being in remission at the time of transplantation should be explored in further studies.

Antileukemia and antitumor effects of the graft-versus-host disease: a new immunovirological approach

In leukemic mice, the native host's explicit and well-defined immune reactions to the leukemia virus (a strong exogenous antigen) and to leukemia cells (pretending in their native hosts to be protected "self" elements) are extinguished and replaced in GvHD (graft-versus-host disease) by those of the immunocompetent donor cells. In many cases, the GvHD-inducer donors display genetically encoded resistance to the leukemia virus. In human patients only antileukemia and anti-tumor cell immune reactions are mobilized; thus, patients are deprived of immune reactions to a strong exogenous antigen (the elusive human leukemia-sarcoma retroviruses). The innate and adaptive immune systems of mice have to sustain the immunosuppressive effects of leukemia-inducing retroviruses. Human patients due to the lack of leukemiainducing retroviral pathogens (if they exist, they have not as yet been discovered), escape such immunological downgrading. After studying leukemogenic retroviruses in murine and feline (and other mammalian) hosts, it is very difficult to dismiss retroviral etiology for human leukemias and sarcomas. Since no characterized and thus recognized leukemogenic-sarcomagenic retroviral agents are being isolated from the vast majority of human leukemias-sarcomas, the treatment for these conditions in mice and in human patients vastly differ. It is immunological and biological modalities (alpha interferons; vaccines; adoptive lymphocyte therapy) that dominate the treatment of murine leukemias, whereas combination chemotherapy remains the main remission-inducing agent in human leukemias-lymphomas and sarcomas (as humanized monoclonal antibodies and immunotoxins move in). Yet, in this apparently different backgrounds in Mus and Homo, GvHD, as a treatment modality, appears to work well in both hosts, by replacing the hosts' anti-leukemia and anti-tumor immune faculties with those of the donor. The clinical application of GvHD in the treatment of human leukemias-lymphomas and malignant solid tumors remains a force worthy of pursuit, refinement and strengthening. Graft engineering and modifications of the inner immunological environment of the recipient host by the activation or administration of tumor memory T cells, selected Treg cells and natural killer (NKT) cell classes and cytokines, and the improved pharmacotherapy of GvHD without reducing its antitumor efficacy, will raise the value of GvHD to the higher ranks of the effective antitumor immunotherapeutical measures. Clinical interventions of HCT/HSCT (hematopoietic cell/stem cell transplants) are now applicable to an extended spectrum of malignant diseases in human patients, being available to elderly patients, who receive non-myeloablative conditioning, are re-enforced by post-transplant donor lymphocyte (NK cell and immune T cell) infusions and post-transplant vaccinations, and the donor cells may derive from engineered grafts, or from cord blood with reduced GvHD, but increased GvL/GvT-inducing capabilities (graft-versus leukemia/tumor). Post-transplant T cell transfusions are possible only if selected leukemia antigen-specific T cell clones are available. In verbatim quotation: "Ultimately, advances in separation of GvT from GvHD will further enhance the potential of allogeneic HCT as a curative treatment for hematological malignancies" (Rezvani, A.R. and Storb, R.F., Journal of Autoimmunity 30:172-179, 2008 (see in the text)). It may be added: for cure, a combination of the GvL/T effects with new targeted therapeutic modalities, as elaborated on in this article, will be necessary.