Nonablative stem cell transplantation for older patients with acute leukemias and myelodysplastic syndromes

Review of stem-cell transplantation for myelodysplastic syndromes in older patients in the context of the Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation for Myelodysplastic Syndrome emanating from the Centers for Medicare and Medicaid Services

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem-cell disorders that result in varying degrees of cytopenia and risk of transformation into acute leukemia. Allogeneic stem-cell transplantation (SCT) is the only known cure for this disease. The treatment is routinely used for younger patients, but only a minority of patients older than the age of 60 undergo this procedure. The overall MDS incidence is 3.3 per 100,000, but the incidence in patients older than age 70 is between 15 and 50 per 100,000. The median age at presentation is 76 years. Medicare-age patients 65 or older represent 80% of the total population receiving an MDS diagnosis. In the United States, one of the obstacles to SCT for older patients with MDS has been lack of third party reimbursement. On August 4, 2010, the Centers for Medicare and Medicaid Services released their Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for Myelodysplastic Syndrome. This memo states: "Allogeneic HSCT for MDS is covered by Medicare only for beneficiaries with MDS participating in an approved clinical study that meets the criteria below…. " In this review, we will summarize what is known regarding the role of allogeneic SCT in older patients as well as other elements that should be included within clinical trials that can provide the evidence necessary to demonstrate that allogeneic SCT should be a covered benefit for Medicare beneficiaries.

Bone marrow engraftment studies

Bone marrow engraftment studies are used to evaluate the level of donor versus recipient cells in post-transplant peripheral blood or bone marrow specimens. Unique DNA fingerprints identified from the recipient and the donor are used to determine the proportion of each contained within the total DNA extracted from the post-transplant specimen. These percentages correspond to relative amounts of donor and recipient cells in the specimen. Engraftment studies are sequentially performed on transplant patients to monitor closely the levels of donor and recipient cells so that appropriate therapeutic intervention can proceed if and when needed. This unit describes the use of fluorescent PCR for amplification of genomic short tandem repeats (STR). STR analysis is now considered the gold standard for engraftment studies and provides a quick and accurate assessment of the contribution of both donor and/or recipient hematopoietic cells in post-transplantation specimens.

Outcome of patients less than 55 years of age with high-risk acute leukemia who did not have an human leukocyte antigen-identical related donor: a long-term study of 97 consecutive patients

Between January 1993 and December 2000, an unrelated donor search (UDS) was initiated for 97 consecutive patients [46 acute lymphoblastic leukemia (ALL) and 51 acute myeloid leukemia (AML)]. Leukemia was considered to be of poor prognosis in cases of refractory disease (n=70), unfavourable karyotype (n=22) or miscellaneous (n=5). All patients had previously received various chemotherapies and 9 had undergone an autologous stem cell transplantation (SCT). The median age at UDS initiation was 25 (range 2.7-55) years. The median time to identify a suitable living donor or cord blood (CB) was 60 days. Eventually, 33 patients received unrelated allo-SCT (including 9 CB), 12 auto-SCT, 39 chemotherapy and 13 palliative treatment. At a median of 54 months, 18 patients were alive, including 15 in remission. The 4-year overall survival rates were 32%, 37%, 15% and 0% for allo-SCT, auto-SCT, chemotherapy or palliative treatment, respectively. Patients who received either allo- or auto-SCT had better survival than those who did not (P<0.0001). For ALL, only allo-SCT significantly improved survival (P<0.007). Finally, patients who received allo-SCT died less often of relapse than patients who did not (P<0.0001). Unrelated allo-SCT gives a substantial long-term survival and cure in patients with high-risk acute leukemia. For patients who achieve remission and for whom UDS fails, auto-SCT may prove to be a good approach. For patients who fail to enter into remission, intensive salvage chemotherapy has a very limited effect.

Bone marrow engraftment studies

Bone marrow engraftment studies are used to evaluate the level of donor versus recipient cells in post-transplant peripheral blood or bone marrow specimens. Unique fingerprints identified from recipient and donor DNA are used to determine the proportion of each contained within the total DNA extracted from the post-transplant specimen. These percentages correspond to relative amounts of donor and recipient cells in the specimen. Engraftment studies are sequentially performed on transplant patients to closely monitor the levels of donor and recipient cells so that appropriate therapeutic intervention can proceed if and when needed. This unit will describe the use of fluorescent PCR for amplification of genomic short tandem repeats (STR). STR analysis is now considered the gold standard for engraftment studies and provides a quick and accurate assessment of the contribution of both donor and/or recipient hematopoietic cells in post-transplantation specimens.

Allogeneic transplantation for the elderly patient with acute myelogenous leukemia or myelodysplastic syndrome

Acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) are diseases of the elderly. Allogeneic hematopoietic stem cell transplantation (HSCT) offers the possibility of cure for these malignancies, but until recently its use was restricted to younger patients due to prohibitive treatment-related mortality. Improvements in supportive care and development of reduced-intensity preparative regimens have allowed patients in the sixth, seventh, and to a lesser extent, eighth decade of life to be treated with allogeneic transplantation. Major obstacles to extending this form of treatment to older patients are lack of promptly available donors, graft-versus-host disease (GVHD), delayed immune recovery, and the high prevalence of refractory and relapsed disease intrinsic to the natural history of these myeloid malignancies. Here we review current results of allogeneic blood and marrow transplantation for AML and MDS in the elderly.

Reduced-Intensity Conditioning Allogeneic Blood Stem Cell Transplantation with Fludarabine and Oral Busulfan with or without Pharmacokinetically Targeted Busulfan Dosing in Patients with Myeloid Leukemia Ineligible for Conventional Conditioning

We prospectively compared outcomes after a fludarabine (Flu) plus oral busulfan (Bu)-containing reduced-intensity conditioning regimen (150 mg/m2 Flu and 10 mg/kg oral Bu), with (n = 32; Flu- T Bu group) or without (n = 30; Flu-Bu group) therapeutic dose monitoring and dose adjustment of Bu. All patients received peripheral blood stem cells from a genoidentical sibling, and study cohorts had similar patient characteristics. Dose adjustments of Bu were required in 20 (63%) patients in the Flu- T Bu group (median final dose, 8.89 mg/kg; range, 6.3-13.34 mg/kg). Donor T-cell and granulocyte engraftments were similar, and early conditioning-related toxicities were mild and similar in both study groups. With a median follow-up of 45 months (51 months in the 37 survivors), posttransplantation outcomes did not differ between cohorts. The strongest predictor of 2-year overall survival and leukemia-free survival was the presence of chronic graft-versus-host disease (77% versus 34% for overall survival and 74% versus 34% for leukemia-free survival; P < .001 for both outcomes). In conclusion, therapeutic dose monitoring of oral Bu in a reduced-intensity conditioning setting does not seem to affect outcome, although further studies may identify very-high-risk patients who benefit from this strategy.

Unrelated donor hematopoietic stem cell transplantation for patients with hematologic malignancies using a nonmyeloablative conditioning regimen of fludarabine, low-dose total body irradiation, and rabbit antithymocyte globulin

Hematopoietic stem cell chimerism can be established after low-dose conditioning regimens, although the risk of donor cell rejection increases for unrelated donor transplantations. We added pretransplantation rabbit antithymocyte globulin (6 mg/kg) to an established conditioning regimen of fludarabine (90 mg/m2) and single-fraction total body irradiation (200 cGy) followed by postgrafting immunosuppression with cyclosporine A and mycophenolate mofetil for 22 patients with hematologic malignancies. One patient rejected the graft and successfully underwent transplantation with cells from a second donor by using the same conditioning regimen. The actuarial probability of developing acute graft-versus-host disease grade II to IV before day 100 was 40%, although 9 of 14 patients who survived beyond 100 days developed chronic graft-versus-host disease. These data support a hypothesis that the addition of antithymocyte globulin decreases the risk of graft-versus-host and host-versus-graft reactions when combined with a nonmyeloablative conditioning regimen of fludarabine and total body irradiation.

Acute Lymphoblastic Leukaemia in Elderly Patients

Acute lymphoblastic leukaemia (ALL) is a rare disease in the elderly. The prevalence of ALL in patients >60 years of age is reported to be between 16% and 31% of all adult cases. The biology of ALL in older patients seems to be significantly different from that in younger patients and may, at least in part, explain poor treatment outcome. Immunophenotyping and cytogenetic characteristics are among the most important biological differences in comparison with younger adults. The frequency of pre B-cell ALL and common ALL is higher and T-cell ALL subtype is under-represented in elderly populations compared with younger patients. The frequency of the Philadelphia chromosome also seems to increase with age and adversely influences complete remission rate and survival. Few reports on the effectiveness and toxicity of therapeutic programmes concerning exclusively older patients with ALL have been published so far and only some of them were prospective studies. In some of the studies age-adapted approaches have been applied in which protocols processed earlier for younger patients have been adopted for older patients. In such modified protocols chemotherapy was usually less aggressive, especially if it was given for patients with comorbidities and poor performance status. Consequently, in several studies elderly patients received suboptimal treatment. Death during induction chemotherapy was observed in 7-42% of the patients in particular reports. The overall response rate varied from 12% to 85%. The median overall survival (OS) durations in patients who received a curative approach ranged from 3 to 14 months and from 1 to 14 months in patients treated palliatively. Poor performance status, comorbidities and high early mortality during intensive chemotherapy are the main reasons for poor treatment results and short OS time. New therapeutic approaches are necessary to improve the outcome in this age group of patients with ALL.

Conditioning with fludarabine and targeted busulfan for transplantation of allogeneic hematopoietic stem cells

A regimen of busulfan and cyclophosphamide is standard therapy before transplantation of allogeneic hematopoietic stem cells in patients with chronic myelogenous leukemia (CML) or myelodysplastic syndrome (MDS). The clinical trial reported here was undertaken to test the hypothesis that fludarabine can replace cyclophosphamide in this regimen and facilitate donor engraftment with reduced toxicity. The conditioning regimen consisted of 30 mg/m2 intravenous fludarabine daily from day -9 to day -6, and oral busulfan given at 1 mg/kg 4 times a day every 6 hours from day -5 to day -2, with doses adjusted to target plasma levels of 900 +/- 100 ng/mL at steady state. Cyclosporine and methotrexate were used for prophylaxis for graft-versus-host disease. Enrolled were 42 patients with high-risk CML (n = 4) or MDS (n = 38). The median patient age was 52 years (range, 12-65 years). Mobilized blood stem cells were obtained from HLA-compatible siblings (n = 16) or unrelated donors (n = 26). Engraftment was achieved in all patients, and the day-100 regimen-related mortality was 7%. With a median follow-up of 18 months (range, 13-27 months), the probabilities of overall survival, disease-free survival, and nonrelapse mortality were 42.4%, 34.9%, and 24%, respectively. These data indicate that the combination of fludarabine and targeted busulfan is sufficiently immunosuppressive to facilitate engraftment of blood stem cells from HLA-matched siblings and unrelated donors. Based on these encouraging results, further studies of fludarabine and targeted busulfan are warranted in standard-risk patients.

Diagnosis, treatment, and nursing care of acute leukemia

OBJECTIVE

To review the clinical presentation, current methods of diagnosis and classification, treatment modalities, and novel treatment approaches of acute myelogenous and lymphoblastic leukemia.

DATA SOURCES

Professional journals, web sites, and books.

CONCLUSION

The incidence of acute leukemia is increasing. As the population ages, it is anticipated that an even greater number will be diagnosed with this malignancy. The development of monoclonal antibodies, the recognition of the benefit of graft versus leukemia effect, and targeted therapies have improved overall survival rates. Still, age remains a significant prognostic variable. More research is needed to improve both the quality and the quantity of life for these patients.

IMPLICATIONS FOR NURSING PRACTICE

Nurses must understand the rationale and implications of each phase of treatment to educate patients, administer treatments, manage side effects, and provide support throughout the continuum of care.

Recent progress in the treatment of myelodysplastic syndrome in adult patients

Peripheral blood cytopenias and dysplastic hematopoietic progenitors characterize the myelodysplastic syndrome. Patients suffer from the consequences of chronic cytopenias or progression to acute myelogenous leukemia. Although allogeneic hematopoietic stem cell transplantation is a potentially curative option, the standard of care for most patients with myelodysplastic syndrome continues to be supportive care, with blood product transfusion and antibiotics for infectious complications. Many patients with myelodysplastic syndrome are not candidates for allogeneic hematopoietic stem cell transplantation because of advanced age, comorbid illnesses, and lack of a histocompatible donor. Increased rates of apoptosis in hematopoietic progenitors, altered production of inflammatory cytokines, neoangiogenesis, and autoreactive T lymphocytes have all been shown to contribute to the phenotype of myelodysplastic syndrome. These recent insights into the pathophysiology of myelodysplastic syndrome have been translated into therapeutic trials of noncytotoxic agents for this disorder. Although clinical responses have been seen with these novel agents, the critical biologic targets have not yet been clearly defined.