Haploidentical vs autologous hematopoietic stem cell transplantation in patients with acute leukemia beyond first remission

Comparison of umbilical cord blood allogeneic stem cell transplantation vs. auto-SCT for adult acute myeloid leukemia patients in second complete remission at transplant: a retrospective study on behalf of the SFGM-TC

This retrospective study considered the outcomes of 181 patients with acute myeloid leukemia (AML) transplanted in second complete remission (CR2) between January 2005 and April 2012 and who received either a myeloablative autologous stem cell transplant (Auto-SCT; n = 82; median age: 48 years; median follow-up: 45 months) or an umbilical cord blood (UCB) allogeneic SCT (n = 99, median age: 46 years; median follow-up: 36 months; conditioning regimens: myeloablative n = 21, reduced n = 78; single unit n = 37, double units n = 62). Although the Auto group showed a significant better prognostic profile at transplant, with longer median interval between diagnosis and time of graft, higher incidence of good-risk cytogenetics and lower number of previously transplanted patients, 3-year OS and LFS were similar between both groups (Auto: 59 ± 6% vs. 50 ± 6%, P = 0.45; and 57 ± 6% vs. 46 ± 6%, P = 0.37). In multivariate analysis, UCB allo-SCT was associated with lower relapse incidence (HR: 0.3, 95% CI: 0.11-0.82, P = 0.02), but higher non-relapse mortality (NRM) (HR: 4.16; 95% CI: 1.46-11.9, P = 0.008). Results from this large study suggest that UCB allo-SCT provides better disease control than auto-SCT, which is especially important in the setting of high-risk disease. However, this disease control advantage is counterbalanced by higher toxicity, highlighting the need for novel approaches aiming to decrease NRM after UCB allo-SCT.

Haploidentical stem cell transplantation

The feasibility of stem cell transplantation across the major histocompatibility barrier-as in haploidentical stem cell transplantation-has been proved for some time in several studies. The main limitations include a higher graft failure rate, delayed immune reconstitution after transplantation with high rates of life-threatening infections, a higher incidence of post-transplant lymphoproliferative disease, and severe acute and chronic graft-versus-host disease. In an attempt to reduce the transplant-related morbidity/mortality, several techniques had been evaluated involving conditioning regimen intensity, graft engineering, post-transplant cellular therapy and immunosuppression. This review will describe the current situation. It will also discuss initiatives and strategies to overcome the limitations associated with transplant across the MHC barrier.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of acute myelogenous leukemia in adults: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (HSCT) in the therapy of acute myelogenous leukemia (AML) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, entitled Summary of Treatment Recommendations Made by the Expert Panel for Adult Acute Myelogenous Leukemia, and were reached unanimously by a panel of AML experts. The identified priority areas of needed future research in adult AML include: (1) What is the role of HSCT in treating patients with specific molecular markers (eg, FLT3, NPM1, CEBPA, BAALC, MLL, NRAS, etc.) especially in patients with normal cytogenetics? (2) What is the benefit of using HSCT to treat different cytogenetic subgroups? (3) What is the impact on survival outcomes of reduced intensity or nonmyeloablative versus conventional conditioning in older (>60 years) and intermediate (40-60 years) aged adults? (4) What is the impact on survival outcomes of unrelated donor HSCT vesus chemotherapy in younger (<40 years) adults with high risk disease?

Natural-killer-cell-based treatment in haematopoietic stem-cell transplantation

Adoptive immunotherapy using natural killer (NK) cells is currently under investigation, especially in situations where anti-neoplastic effect is needed but infusion of T cells is considered hazardous, such as in recipients of haematopoietic stem-cell transplantation (HSCT) from haploidentical donors. NK-cell therapy is mainly but not exclusively investigated in the setting of allogeneic stem-cell transplantation. NK cells may induce potent anti-leukaemic and possibly anti-rejection activity, and may even mitigate graft-versus-host disease (GvHD). It remains to be determined whether such effects are clinically important and whether or not they are mediated mainly or exclusively by KIR-HLA class I interactions. Recent advances in graft engineering has provided methods for isolating large numbers of purified NK cells. Several groups have shown that clinical-grade NK cells at doses up to 10(7)/kg may be collected and purified for the purpose of infusion to patients. Early results in a limited number of patients show that these cell doses may be administered without adverse events and possibly without inducing GvHD. Further study is required to determine whether such infusions will be useful in preventing graft rejection, exerting graft-versus-leukaemia effects, and/or hastening immune recovery.

Haemopoietic progenitor cell transplantation in patients with previous history of invasive fungal infection

The aim of this retrospective study conducted between H.U. Marques de Valdecilla (Spain) and the Royal Marsden NHS Trust (UK) was to analyse the outcome of patients who underwent haemopoietic progenitor cell transplantation (HPCT) after a previous history of Invasive fungal infections (IFI). This study includes 27 patients (15 autologous, 12 allogeneic). The diagnosis of IFI was microbiologically proven in 21 cases and only radiologically in six. Pre-HPCT treatment included intravenous antifungals in all and surgical excision in eight cases. All patients received post-HPCT antifungal prophylaxis. Median time from diagnosis of IFI to HPCT was 131 days. At median follow-up of 193 days, three patients (two allogeneic, one autologous) had relapse of IFI resulting in death in all cases. One of them had received TBI and two were receiving treatment for graft versus host disease. Each patient was receiving a different form of prophylaxis. Overall, seven patients are alive and disease-free. Ten patients died from disease progression and 10 from transplant-related toxicity, including IFI. In our experience, the risk of post-HPCT reactivation of a previous IFI is low (11%), so IFI should not be an absolute contraindication for HPCT. The combination of aggressive antifungal treatment for IFI and antifungal prophylaxis throughout HPCT reduces the probability of reactivation.

Emerging drugs for adult acute lymphoblastic leukaemia

Although most patients with adult acute lymphoblastic leukaemia (ALL) can achieve a remission when treated with conventional, DNA-damaging chemotherapy, in more than half of all cases the disease relapses and ultimately results in death. Therefore, there is a substantial need for new antileukaemic drugs. Recent advances in the understanding of the molecular alterations in ALL have lead to the identification of new targets and the arrival of molecular-targeted therapies in the clinical setting. The prototype for this approach is the treatment of Philadelphia chromosome-positive ALL with imatinib mesylate. Here, the targeting of a molecular abnormality--inhibition of BCR-ABL tyrosine kinase--has turned a very poor-prognosis disease into one in which promising results are achieved. Promising new therapies are under development that target various goals, including the NOTCH signalling pathway, purine nucleoside phosphorylase activity, mammalian target of rapamycin and tyrosine kinase. This review outlines recent advances in the development of emerging drugs for the treatment of adult ALL. The recent advances in the understanding of the biology and pathogenesis of ALL have helped to determine prognosis and to plan the therapy of adult patients with ALL. Still, despite improved complete remission rates of 65-90% with current therapy, only 20-40% of patients can be considered cured. New therapeutic alternatives are needed to improve these results. With a better understanding of the disease, more target-specific therapies could be designed. The aim of this review is to highlight new pharmacotherapies and those emerging drug treatments for patients with adult ALL.

Hematopoietic stem cell transplantation after first marrow relapse of non-T, non-B acute lymphoblastic leukemia: a pediatric oncology group pilot feasibility study

BACKGROUND

Relapsed acute lymphoblastic leukemia (ALL) in children is associated with a poor outcome, especially for those patients whose relapse occurs during the first 36 months after diagnosis. The best therapy for these patients is not known. This study was designed to evaluate the feasibility of enrolling children with recurrent ALL in a standardized treatment protocol that included receipt of a hematopoietic stem cell transplant (HSCT).

PROCEDURE

Eligible patients with a bone marrow relapse of non-T, non-B ALL underwent a common induction and consolidation followed by receipt of either an allogeneic HSCT from a human leukocyte antigen (HLA)-identical sibling or an autologous HSCT purged with B-4 blocked ricin. A common conditioning regimen was used for all patients.

RESULTS

Twenty-eight patients from eight institutions were enrolled. Fourteen patients did not receive a transplant during the study, because of toxicity (4), relapse (1), inadequate purging (1), and parental or physician preference for an alternative donor transplant (8). Six patients received allogeneic HSCTs. Five of them have remained in remission for a median of 78 months. Eight patients received autologous HSCTs purged with B4-blocked ricin. Four have remained in remission for a median of 94 months. Of the nine patients who received alternative donor transplants, only two remain in remission.

CONCLUSION

We conclude that well designed and controlled prospective studies are necessary to define the role of HSCTs in children with recurrent ALL. In order to be successful, such studies must have the full support of participating centers. Autologous HSC transplantation may have a role in the treatment of relapsed ALL, but further studies are needed.

Use of natural killer cells in hematopoetic stem cell transplantation

Adoptive immunotherapy using natural killer (NK) cells may prove useful, especially in situations where infusion of T cells is impractical such as in recipients of haploidentical stem cell transplantation (HSCT) from haploidentical donors. NK cells may induce potent antileukemic and possibly antirejection activity and may even mitigate graft versus host disease (GvHD). Whether such effects are clinically important and whether they are mediated mainly or exclusively by KIR-HLA class I interactions remains to be determined. Recent advances in graft engineering provide for methods to isolate large numbers of purified NK cells. Several groups have shown that clinical grade NK cells up to a dose of 10(7)/kg may be collected and purified for the purpose of infusion to patients. Early results, in a limited number of patients, show that these cell doses may be administered without adverse events and without inducing GvHD. Whether such infusions will be useful in preventing graft rejection, or exerting graft versus leukemia effects and hastening immune recovery requires further study.

Haploidentical transplantation for acute lymphoblastic leukemia in childhood

Haploidentical transplantation in childhood acute lymphoblastic leukemia (ALL) is a promising option for children lacking a suitable donor. We have updated our series of patients with ALL and report the results. Additionally, we reviewed the literature and try to embed our own experiences in the published results. We performed HLA-mismatched stem cell transplantations with megadoses of purified positively selected mobilized peripheral blood CD34+ progenitor cells (PBPC) from adult donors in 27 children with acute lymphoblastic leukemia (ALL) in first (CR1 n = 7), second (CR2 n = 10), or third (CR3 n = 4) complete remission, and in refractory state (NR n = 6). The patients received a mean number of 19.1+/-11.3 x 10(6)/kg purified CD34+ and a mean number of 15.5+/-24.2 x 10(3)/kg CD3+ T-cells. No additional graft-versus-host disease (GVHD) prophylaxis was used, except as short-term CSA in the first 3 patients. The myeloablative treatment was based on busulfan in 12 and on TBI in 14 patients. One patient was grafted with a non-myeloablative approach. Engraftment was rapid in 26 patients, with two patients suffering from a rejection. These two and one patient with initial non-engraftment had been successfully regrafted. The probability of survival of the total group is 0.34+/-0.09; the 12 patients transplanted in remission showed a probability of survival of 0.44+/-0.11. None of the patients transplanted in non-remission survived. There was no statistical difference in survival for patients with a 1, 2 or 3 antigen mismatched donor (out of 6 HLA antigens) or for patients in 1st, 2nd or 3rd remission. Causes of death were relapses in 10 patients, veno-occlusive disease (VOD) in 1, multi-organ failure (MOF) in 2 and infections in 4 patients. 3/24 evaluable patients without any additional GVHD-prophylaxis developed grade 1 or 2 GVHD. Ten patients were treated with additional donor lymphocyte infusion (DLI), from which 4 developed a maximum grade 3 GVHD. We conclude that the HLA barrier can be overcome by transplantation of megadoses of highly purified CD34+ PBPC and GVHD can effectively be prevented. This approach offers a promising treatment option for patients with acute lymphoblastic leukemia needing urgently transplantation but lacking a suitable donor.

Bone marrow transplantation from partially HLA-mismatched family donors for acute leukemia: single-center experience of 201 patients

Between February 1993 and December 1999, 201 patients (1-59 years old, median 23) with acute leukemia (67% not in remission) underwent ex vivo T-cell-depleted (TCD) bone marrow transplants (BMT) from partially mismatched related donors (PMRD; 92% mismatched for 2-3 HLA A, B, DR antigens). Conditioning comprised total body irradiation, cyclophosphamide, cytarabine, etoposide, anti-thymocyte globulin (ATG), and methylprednisolone. Graft-versus-host disease (GVHD) prophylaxis comprised partial TCD with OKT3 (n=143) or T10B9 (n=58), steroids, ATG, and cyclosporine. The engraftment rate was 98%. The cumulative incidences of grades II-IV acute GVHD and chronic GVHD were 13 and 15%, respectively. The 5-year cumulative incidences of relapse and transplant-related mortality (TRM) were 31 and 51%, respectively. The actuarial 5-year overall survival (OS) and disease-free survival (DFS) probabilities were 19 and 18%, respectively. Patient age >15 years, active disease at transplant, donor age >25 years, and 3-antigen donor mismatch (host-versus-graft) affected the outcome adversely. The actuarial 5-year OS of four groups of patients identified based upon these risk factors was 39, 20, 13, and 0%, respectively (P<0.0001). We conclude that PMRD BMT is a potential treatment option for patients with high-risk acute leukemia who require an alternative donor transplant and fall into a group with a reasonable expected outcome.