Unrelated transplantation for poor-prognosis adult acute lymphoblastic leukemia: long-term outcome analysis and study of the impact of hematopoietic graft source

Prognosis of patients with acute lymphoblastic leukaemia relapsing after allogeneic stem cell transplantation

The outcomes of patients with acute lymphoblastic leukaemia (ALL) presenting relapse after allogeneic stem cell transplant (allo-SCT) are poor, with few data available in this setting.

OBJECTIVE AND METHODS

To evaluate the outcomes of patients with ALL presenting relapsed after allo-SCT, we performed a retrospective study including 132 from 11 centres in Spain.

RESULTS

Therapeutic strategies consisted of palliative treatment (n = 22), chemotherapy (n = 82), tyrosine kinase inhibitors (n = 26), immunotherapy with inotuzumab and/or blinatumumab (n = 19), donor lymphocyte infusions (n = 29 pts), second allo-SCT (n = 37) and CAR T therapy (n = 14). The probability of overall survival (OS) at 1 and 5 years after relapse was 44% (95% confidence interval [CI]: 36%; 52%) and 19% (95% CI: 11%; 27%). In the 37 patients undergoing a second allo-SCT, the 5-year estimated OS probability was 40% [22%; 58%]. Younger age, recent allo-SCT, late relapse, 1st complete remission at 1st allo-SCT and chronic graft-versus-host disease confirmed their positive impact on survival in the multivariable analysis.

CONCLUSION

Despite the poor prognosis of patients with ALL presenting relapse after a first allo-SCT, some can be satisfactorily rescued and a second allo-SCT still remains a valid option for selected patients. Moreover, emerging therapies really might improve ALL patients outcome when relapsing after an allo-SCT.

How I Use Measurable Residual Disease in the Clinical Management of Adult Acute Lymphoblastic Leukemia

Over the last decade the use of measurable residual disease (MRD) diagnostics in adult acute lymphoblastic leukemia (ALL) has expanded from a limited number of study groups in Europe and the United States to a world-wide application. In this review, we summarize the advantages and drawbacks of the current available techniques used for MRD monitoring. Through the use of three representative case studies, we highlight the advances in the use of MRD in clinical decision-making in the management of ALL in adults. We acknowledge discrepancies in MRD monitoring and treatment between different countries, reflecting differing availability, accessibility and affordability.

Radiation-Free myeloablative allogeneic hematopoietic stem cell transplantation for adult acute lymphoblastic leukemia: A comparison of outcomes between patients with and without central nervous system involvement

For patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), total body irradiation (TBI) has been particularly advocated as a part of the conditioning regimen in case of extramedullary involvement in sanctuary sites such as the central nervous system (CNS), to ensure greater tissue penetration. In resource-limited countries lacking TBI facilities; however, ALL patients undergo radiation-free myeloablative conditioning, though its impacts on post-HSCT outcomes of the patients with pre-HSCT CNS involvement have not been analyzed. In this 14-year series of 278 adult (> 18 y) ALL patients undergoing TBI-free busulfan/cyclophosphamide conditioning allo-HSCT, we found that the long-term probabilities of overall survival, disease free survival, relapse and non-relapse mortality were not significantly different between CNS-involved and CNS-spared patients. Moreover, there was no statistically significant difference in the incidence of post-HSCT CNS relapse between CNS-involved and CNS-spared patients. Pre-HSCT cranial radiation therapy (CRT) showed no significant preventive effect on the likelihood of post-HSCT CNS relapse. Through multivariable regression analysis, grade III-IV acute graft-versus-host disease (GvHD), extensive chronic GvHD and post-HSCT relapse were ascertained as independent determinants of mortality (Adj.R² = 53.9 %, F_(12,265) = 28.1, P < 0.001), while other parameters including Philadelphia translocation, pre-HSCT CNS involvement and CRT were found to have no independent effect. Although this study was not an attempt to compare TBI-based vs. non-TBI conditioning, the TBI-free myeloablative allo-HSCT was shown to be feasible and an option for adult ALL patients with CNS involvement, considering the comparable outcomes between patients with and without CNS involvement.

A risk score system for stratifying the risk of relapse in B cell acute lymphocytic leukemia patients after allogenic stem cell transplantation

BACKGROUND

For patients with B cell acute lymphocytic leukemia (B-ALL) who underwent allogeneic stem cell transplantation (allo-SCT), many variables have been demonstrated to be associated with leukemia relapse. In this study, we attempted to establish a risk score system to predict transplant outcomes more precisely in patients with B-ALL after allo-SCT.

METHODS

A total of 477 patients with B-ALL who underwent allo-SCT at Peking University People's Hospital from December 2010 to December 2015 were enrolled in this retrospective study. We aimed to evaluate the factors associated with transplant outcomes after allo-SCT, and establish a risk score to identify patients with different probabilities of relapse. The univariate and multivariate analyses were performed with the Cox proportional hazards model with time-dependent variables.

RESULTS

All patients achieved neutrophil engraftment, and 95.4% of patients achieved platelet engraftment. The 5-year cumulative incidence of relapse (CIR), overall survival (OS), leukemia-free survival (LFS), and non-relapse mortality were 20.7%, 70.4%, 65.6%, and 13.9%, respectively. Multivariate analysis showed that patients with positive post-transplantation minimal residual disease (MRD), transplanted beyond the first complete remission (≥CR2), and without chronic graft-versus-host disease (cGVHD) had higher CIR (P  < 0.001, P = 0.004, and P  < 0.001, respectively) and worse LFS (P  < 0.001, P = 0.017, and P  < 0.001, respectively), and OS (P  < 0.001, P = 0.009, and P  < 0.001, respectively) than patients without MRD after transplantation, transplanted in CR1, and with cGVHD. A risk score for predicting relapse was formulated with the three above variables. The 5-year relapse rates were 6.3%, 16.6%, 55.9%, and 81.8% for patients with scores of 0, 1, 2, and 3 (P  < 0.001), respectively, while the 5-year LFS and OS values decreased with increasing risk score.

CONCLUSION

This new risk score system might stratify patients with different risks of relapse, which could guide treatment.

Hematopoietic Cell Transplantation in the Treatment of Adult Acute Lymphoblastic Leukemia: Updated 2019 Evidence-Based Review from the American Society for Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in adults with acute lymphoblastic leukemia (ALL) is reviewed 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 recommendations. A panel of ALL experts developed consensus on the treatment recommendations based on the evidence. Allogeneic HCT offers a survival benefit in selected patients with ALL, and this review summarizes the standard indications as well as the areas of controversy. There is now greater experience with pediatric-inspired chemotherapy regimens that has transformed upfront therapy for adult ALL, resulting in higher remission rates and overall survival. This in turn has increased the equipoise around decision making for ALL in first complete remission (CR1) when there is no measurable residual disease (MRD) at the end of induction and/or consolidation. Randomized studies are needed for adults with ALL to compare allogeneic HCT in CR1 with pediatric-inspired chemotherapy alone. Indications for transplantation in the evolving landscape of MRD assessments and novel targeted and immune therapeutics remain important areas of investigation.

[Allogeneic hematopoietic stem cell transplantation for treatment of refractory and relapsed acute myeloid leukemia: outcomes and prognostic factors]

目的

评价异基因造血干细胞移植（allo-HSCT）治疗难治/复发急性髓系白血病（AML）的疗效，并对预后相关因素进行分析。

方法

回顾性分析allo-HSCT治疗99例难治/复发AML患者总体生存（OS）率、无病生存（DFS）率、移植物抗宿主病（GVHD）发生率、移植相关死亡率（TRM）及复发率，并分析影响预后的危险因素。

结果

全部99例患者中男59例，女40例，中位年龄为35（6~58）岁，均接受清髓性预处理。所有患者中性粒细胞均达植入标准，中位植活时间为14（9~25）d。移植后100 d Ⅱ~Ⅳ度急性GVHD累积发生率为27.3%（95% CI 18.9%~36.3%）；2年慢性GVHD累积发生率为33.9%（95%CI 24.6%~43.5%），其中广泛型慢性GVHD累积发生率为9.3%（95%CI 4.5%~16.1%）。移植后3年OS、DFS、TRM率分别为45.0%（95%CI 34.6%~55.4%）、45.0%（95%CI 34.8%~55.2%）、19.7%（95%CI 12.4%~28.3%），复发率为36.6%（95%CI 26.9%~46.4%）。多因素分析显示，影响OS的独立危险因素包括移植前未缓解[P=0.009，HR=2.21（95%CI 1.22~4.04）]、初诊WBC>50×10⁹/L[P=0.024，HR=2.11（95%CI 1.11~4.02）]、供者年龄>35岁[P=0.031，HR=1.96（95%CI 1.06~3.60）]、移植后未发生慢性GVHD[P=0.008，HR=0.38（95%CI 0.18~0.78）]。根据移植前危险因素（移植前未缓解、初诊WBC>50×10⁹/L、供者年龄>35岁）进行危险度分组，具有0、1、2~3个危险因素患者的3年OS率分别为75.0%、46.9%、15.4%（χ²=26.873，P<0.001）。

结论

allo-HSCT是挽救性治疗难治/复发AML的有效手段，复发是影响生存的主要原因。移植前缓解状态、发病时WBC水平、供者年龄及移植后是否发生慢性GVHD是难治/复发AML患者allo-HSCT预后的独立影响因素。

Infectious Complications after Umbilical Cord-Blood Transplantation from Unrelated Donors

Umbilical cord-blood (UCB) is a well-recognized alternative source of stem cells for unrelated donor hematopoietic stem cell transplantation (HSCT). As compared with other stem cell sources from adult donors, it has the advantages of immediate availability of cells, absence of risk to the donor and reduced risk of graft-versus-host disease despite donor-recipient HLA disparity. However, the use of UCB is limited by the delayed post-transplant hematologic recovery due, at least in part, to the reduced number of hematopoietic cells in the graft and the delayed or incomplete immune reconstitution. As a result, severe infectious complications continue to be a leading cause of morbidity and mortality following UCB transplantation (UCBT). We will address the complex differences in the immune properties of UCB and review the incidence, characteristics, risk factors, and severity of bacterial, fungal and viral infectious complications in patients undergoing UCBT.

The Superiority of Allogeneic Hematopoietic Stem Cell Transplantation Over Chemotherapy Alone in the Treatment of Acute Myeloid Leukemia Patients with Mixed Lineage Leukemia (MLL) Rearrangements

BACKGROUND Acute myeloid leukemia (AML) patients with mixed lineage leukemia (MLL) gene rearrangements always had a very poor prognosis. In this study, we report the incidence of MLL rearrangements in AML patients using gene analysis, as well as the clinical significance and prognostic features of these rearrangements. MATERIAL AND METHODS This retrospective study took place from April 2008 to November 2011 in the People's Liberation Army General Hospital. A total 433 AML patients were screened by multiple nested reverse transcription polymerase chain reaction (RT-PCR) to determine the incidence of the 11 MLL gene rearrangements. There were 68 cases of MLL gene rearrangements, for a positive rate of 15.7%. A total of 24 patients underwent allogeneic hematopoietic stem cell transplantation (Allo-HSCT), and 34 patients received at least 4 cycles of chemotherapy. Ten patients were lost to follow-up. RESULTS The median follow-up was 29 months. The complete remission (CR) rate was 85.4%. The overall survival (OS) was 57.4±5.9 months for the Allo-HSCT group and 21.0±2.1 months for the chemotherapy group. The Allo-HSCT group had superior survival compared with the chemotherapy group (5-year OS: 59±17% vs. 13±8%, P<0.01; 5-year disease-free survival [DFS]: 65±10% vs. 40±16%, P>0.05). Multivariate analysis showed that transplantation, platelets >50×10^9/L at onset, and CR are associated with a better OS in MLL rearranged AML patients. Patients with thrombocytopenia and extramedullary involvement were prone to relapse. CONCLUSIONS Our results suggest that Allo-HSCT is superior to chemotherapy alone for treating MLL rearranged AML patients. Patients treated with Allo-HSCT have a better prognosis and a longer survival. CR is an independent prognostic factor for OS, and extramedullary involvement is an independent prognostic factor for DFS. MLL rearranged AML patients with thrombocytopenia at onset <50×10^9 had very bad OS and DFS.

Risk factors for outcomes after unrelated cord blood transplantation for adults with acute lymphoblastic leukemia: a report on behalf of Eurocord and the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

We performed a retrospective analysis on 421 adult patients who underwent unrelated cord blood transplantation (UCBT) for ALL. Median age was 32 years; 46% were in first CR (CR1), 32% in CR2 and 22% had advanced disease. Double UCBT was performed in 173 patients (41%). Myeloablative conditioning (MAC) was given to 314 patients (75%). Cumulative incidence (CI) of 60-day neutrophil recovery was 78%. CI of acute and chronic GVHD was 33 and 26%, respectively. Non-relapse mortality (NRM) at 2 years was 42%. Age⩾35 years (P<0.0001), advanced disease at UCBT (P<0.0001) and use of MAC (P<0.0001) were associated with increased NRM. Relapse incidence (RI) at 2 years was 28%; use of reduced intensity conditioning (RIC) (P=0.0002) was associated with increased RI. Two-year leukemia-free survival (LFS) was 39% for patients in CR1, 31% for CR2 and 8% for advanced disease. In multivariate analysis, factors associated with decreased LFS rate were: age ⩾35 years (P=0.034), use of MAC (P=0.032) and advanced disease (P<0.0001). These results show that UCBT is a valuable option to treat high-risk adult ALL when in remission. Strategies to decrease toxicity and relapse are needed to improve final outcomes.

Role of allogeneic hematopoietic stem cell transplantation in adult patients with acute lymphoblastic leukemia

Adult acute lymphoblastic leukemia (ALL) is a heterogeneous disease, due to the expression of different biological and clinical risk factors, for which allogeneic stem cell transplantation (alloHSCT) is an effective consolidation therapy. The non-relapse mortality of alloHSCT remains significantly higher compared with that of conventional chemotherapy. Therefore, one of the main challenges in the care of ALL is to establish a more precise prognostic definition to select patients who could take advantage from an alloHSCT. Currently, the use of minimal residual disease following induction and early consolidation therapy has improved the prognostic accuracy in defining ALL risk class. In Philadelphia-positive ALL, the introduction of tyrosine kinase inhibitors pre and post alloHSCT appears to improve outcomes significantly and, in the absence of specially designed clinical trials, alloHSCT remains the most effective post-remission therapy. Nowadays, alloHSCT can be performed according to various modalities encompassing the use of different conditioning regimens, as well as distinct donors and stem cell source, with a significant accessibility to transplant.

Impact of minimal residual disease on outcomes after umbilical cord blood transplantation for adults with Philadelphia-positive acute lymphoblastic leukaemia: an analysis on behalf of Eurocord, Cord Blood Committee and the Acute Leukaemia working party of the European group for Blood and Marrow Transplantation

The status of umbilical cord blood transplantation (UCBT) in adults with Philadelphia-positive acute lymphoblastic leukaemia (Ph+ALL) and the impact of minimal residual disease (MRD) before transplant are not well established. We analysed 98 patients receiving UCBT for Ph+ALL in first (CR1) or second (CR2) complete remission (CR1, n = 79; CR2, n = 19) with MRD available before UCBT (92% analysed by reverse transcription polymerase chain reaction). Median age was 38 years and median follow-up was 36 months; 63% of patients received myeloablative conditioning and 42% received double-unit UCBT. Eighty-three patients were treated with at least one tyrosine kinase inhibitor before UCBT. MRD was negative (-) in 39 and positive (+) in 59 patients. Three-year cumulative incidence of relapse was 34%; 45% in MRD+ and 16% in MRD- patients (P =0·013). Three-year cumulative incidence of non-relapse mortality was 31%; it was increased in patients older than 35 years (P = 0·02). Leukaemia-free survival (LFS) at 3 years was 36%; 27% in MRD+ and 49% in MRD- patients (P = 0·05), and 41% for CR1 and 14% for CR2 (P = 0·008). Multivariate analysis identified only CR1 as being associated with improved LFS. In conclusion, MRD+ before UCBT is associated with increased relapse. Strategies to decrease relapse in UCBT recipients with Ph+ALL and MRD+ are needed.

Umbilical cord blood transplantation from unrelated donors in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

There are very few disease-specific studies focusing on outcomes of umbilical cord blood transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia. We report the outcome of 45 patients with Philadelphia chromosome-positive acute lymphoblastic leukemia who underwent myeloablative single unit cord blood transplantation from unrelated donors within the GETH/GITMO cooperative group. Conditioning regimens were based on combinations of thiotepa, busulfan, cyclophospamide or fludarabine, and antithymocyte globulin. At the time of transplantation, 35 patients (78%) were in first complete remission, four (8%) in second complete remission and six (14%) in third or subsequent response. The cumulative incidence of myeloid engraftment was 96% at a median time of 20 days and significantly better for patients receiving higher doses of CD34(+) cells. The incidence of acute grade II-IV graft-versus-host disease was 31%, while that of overall chronic graft-versus-host disease was 53%. Treatment-related mortality was 17% at day +100 and 31% at 5 years. The 5-year relapse, event-free survival and overall survival rates were 31%, 36% and 44%, respectively. Although the event-free and overall survival rates in patients without BCR/ABL transcripts detectable at time of transplant were better than those in whom BCR/ABL transcripts were detected (46% versus 24% and 60% versus 30%, respectively) these differences were not statistically significant in the univariate analysis (P=0.07). These results demonstrate that umbilical cord blood transplantation from unrelated donors can be a curative treatment for a substantial number of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia.

When, how, and what cell source for hematopoietic cell transplantation in first complete remission adult acute lymphoblastic leukemia?

Adult acute lymphoblastic leukemia (ALL) is a heterogeneous disease affected by many patient- and disease-related factors, including age, immunologic subtype, and clinical, genetic, and molecular features. Allogeneic hematopoietic cell transplantation (HCT) has occupied an increasing therapeutic role as a result of significant improvements in supportive care and histocompatibility testing. ALL Philadelphia chromosome–negative patients formerly excluded now are considered HCT candidates and survival rates with alternative donors may approach those obtained with matched-related donors. Reduced-intensity conditioning rather than myeloablative conditioning appears to provide comparable patient outcome results although these observations have not been validated in prospective studies. Improved tools can identify patients thought to be in remission based on morphology but who have active disease at the molecular or immunophenotypic level (minimal residual disease). Using B-cell antigen panels, clone-specific immunoglobulins, or T-cell receptor rearrangements to detect positivity at thresholds of at least 1 in 104 cells, such patients may be taken to HCT. The ongoing advances in conventional therapy intensity, however, now yield improved results and ongoing reassessment of the place of HCT needs to be continued; every effort should be made to enroll eligible patients in clinical trials.

Optimal approach to treatment of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: how to best use all the available tools

Approximately 20% of adult and 50% of elderly patients with acute lymphoblastic leukemia (ALL) express the t(9;22) chromosome translocation with BCR-ABL rearrangement. The use of tyrosine kinase inhibitors (TKIs) has resulted in higher rates of complete remission (95-100%), and many fit patients are able to receive allogeneic hematopoietic stem cell transplant (HSCT). TKI-containing induction followed by myeloablative allogeneic HSCT has resulted in long-term survival between 50 and 60% in young adults, and recent reports show promising results in patients submitted to non-myeloablative HSCT. The prognosis of elderly patients with Philadelphia chromosome-positive (Ph+) ALL is poor despite a high complete remission (CR) rate with TKIs and minimal chemotherapy, and improvements are clearly needed in this subgroup of patients. This review summarizes and discusses current challenges in the treatment of patients with Ph+ ALL, such as selection of the appropriate induction therapy, minimization of transplant toxicity, correct use of TKIs after transplant, BCR-ABL monitoring, the study of mutations which confer resistance to TKIs and new drugs to overcome this resistance.

Quantification of minimal residual disease levels by flow cytometry at time of transplant predicts outcome after myeloablative allogeneic transplantation in ALL

The potential impact on patient outcome of different Minimal residual disease (MRD) levels at time of transplant in patients with lymphoblastic leukemia undergoing allogeneic hematopoietic SCT (HSCT) remains uncertain. In this study, we quantified MRD levels at time of transplant using multiparameter flow cytometry (MFC). Mononuclear cells from marrow aspirates were obtained from 102 adult and child patients before their conditioning regimen. Quantification of MRD levels was carried out by detecting patient-specific leukemia-associated immunophenotypes using four-color MFC. Thirty patients exhibited measurable levels of MRD at the time of transplant, with low levels (0.01 to 0.1%) in 12 cases, intermediate levels (>0.1 to 1%) in 8 cases and high levels (>1%) in 10 cases. The leukemia-free survival (LFS) rates were 65.9±7.0%, 42.9±15.7% and 0% for negative, low levels 0.1% and intermediate-high levels >0.1%, respectively (P<0.001, log-rank test). Overall survival (OS) was 52.3±7.6%, 28.6±13.8% and 0% for MRD-negative, low levels 0.1% and intermediate-high levels >0.1%, respectively (P<0.001, log-rank test). Multivariate Cox analysis confirmed that detection of leukemia cells by flow cytometry at transplant was the most significantly adverse factor for OS, LFS and EFS after transplant.

Prognostic factors in patients aged 50 years or older undergoing allogeneic hematopoietic stem cell transplantation for hematologic malignancy

We retrospectively analyzed patients aged C 50 years with hematologic malignancies who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) to identify preoperative variables predicting the outcome. There were 71 patients with a median age of 57 years (range: 50-63 years) who had acute leukemia (n = 53) or myelodysplastic syndrome (n = 18). Myeloablative conditioning was done in 35 patients and 36 patients had reduced-intensity conditioning. The 5-year overall survival rate (OS), cumulative relapse rate, and non-relapse mortality rate (NRM) were 45, 24, and 33%, respectively. According to multivariate analysis, high-risk disease (HR 3.50, 95% CI 1.43-8.56, P = 0.006), a hematopoietic cell transplantation comorbidity index (HCT-CI) score ≥ 3 (HR 4.41, 95% CI 1.31-14.77, P = 0.016), and an HLA-mismatched unrelated donor (HR 4.03, 95% CI 1.46-11.10, P = 0.007) were significant predictors of worse OS. Highrisk disease was also significantly associated with a higher cumulative relapse rate (HR 4.59, 95% CI 0.94-6.92, P = 0.065). Furthermore, an HCT-CI score ≥ 3 (HR 3.02, 95% CI 1.01-20.78, P = 0.048) and an HLA-mismatched unrelated donor (HR 3.02, 95% CI 1.04-8.74, P = 0.042) were risk factors for NRM. These results suggest that the disease risk, HCT-CI score, and donor type/histocompatibility are prognostic factors for elderly patients, while the conditioning regimen and age are not predictors.

Allogeneic cord blood transplantation for adult acute lymphoblastic leukemia: retrospective survey involving 256 patients in Japan

We investigated the efficacy of cord blood transplantation (CBT) for adult acute lymphoblastic leukemia (ALL) by reviewing medical records of 256 patients reported to the Japan Cord Blood Bank Network between June 1997 and August 2006. Cumulative incidence of neutrophil engraftment at day 100 was 78%. Infused CD34-positive cell dose (>1 × 10(5) cells/kg) was associated with successful neutrophil engraftment. Cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) at day 100 was 37%. A 2-year disease-free and overall survival (OS) rates were 36% and 42%, respectively. Multivariate analysis showed that age (51 or older vs younger than 50) (hazard ratio 1.9, 95% confidence interval (CI), 1.3-2.8, P=0.001), disease status (non-remission vs remission) (hazard ratio 2.2, 95% CI, 1.5-3.2, P<0.0001), grade III-IV acute GVHD (hazard ratio 2.0, 95% CI, 1.2-3.2, P=0.006) and absence of chronic GVHD (hazard ratio 2.4, 95% CI, 1.1-5.1, P=0.02) were negatively associated with OS. CBT is effective for some patients with advanced ALL. It is worth considering for further evaluation.

Advances in acute lymphoblastic leukemia in adults

PURPOSE OF REVIEW

This review will be focused on the advances in adult acute lymphoblastic leukemia (ALL) based on recently published articles.

RECENT FINDINGS

Progress in the understanding of the molecular basis of ALL has contributed to a more precise definition of risk factors. The study of minimal residual disease has re-defined the baseline prognostic factors and has opened new strategies for postremission management. The use of pediatric-inspired therapies for young adults with standard-risk ALL, the broadening of the number of patients who are eligible for allogeneic stem cell transplantation, the increasing use of targeted therapies (monoclonal antibodies, tyrosine kinase inhibitors, and new purine analogs, etc.) in early phases of the disease, together with the improvements in supportive therapy explain the increased survival of young and middle-aged adult ALL.

SUMMARY

These changes are improving long-term outcome, which in ongoing studies is expected to be of close to 50%, and are opening the door for future therapeutic advances.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the treatment of adult acute lymphoblastic leukemia: update of the 2006 evidence-based review

Clinical research published since the first evidence-based review on the role of hematopoietic stem cell transplantation (SCT) in the treatment of acute lymphoblastic leukemia (ALL) in adults is presented and critically evaluated in this update. Treatment recommendations changed or modified based on new evidence include: (1) myeloablative allogeneic SCT is an appropriate treatment for adult (<35 years) ALL in first complete remission for all disease risk groups; and (2) reduced-intensity conditioning may produce similar outcomes to myeloablative regimens. Treatment recommendations unchanged or strengthened by new evidence include: (1) allogeneic SCT is recommended over chemotherapy for ALL in second complete remission or greater; (2) allogeneic is superior to autologous SCT; and (3) there are similar survival outcomes after related and unrelated allogeneic SCT. New treatment recommendations based on new evidence include: (1) in the absence of a suitable allogeneic donor, autologous SCT may be an appropriate therapy, but results in a high relapse rate; (2) it is appropriate to consider cord blood transplantation for patients with no HLA well-matched donor; and (3) imatinib therapy before and/or after SCT (for Ph+ ALL) yields significantly superior survival outcomes. Areas of needed research in the treatment of adult ALL with SCT were identified and presented in the review.

Three-dimensional culture and bioreactors for cellular therapies

A bioreactor is defined as a specifically designed vessel to facilitate the growth of organisms and cells through application of physical and/or electrical stimulus. When cells with therapeutic potential were first discovered, they were initially cultured and expanded in two-dimensional (2-D) culture vessels such as plates or T-flasks. However, it was soon discovered that bioreactors could be used to expand and maintain cultures more easily and efficiently. Since then, bioreactors have come to be accepted as an indispensable tool to advance cell and tissue culture further. A wide array of bioreactors has been developed to date, and in recent years businesses have started supplying bioreactors commercially. Bioreactors in the research arena range from stirred tank bioreactors for suspension culture to those with various mechanical actuators that can apply different fluidic and mechanical stresses to tissues and three-dimensional (3-D) scaffolds. As regenerative medicine gains more traction in the clinic, bioreactors for use with cellular therapies are being developed and marketed. While many of the simpler bioreactors are fit for purpose, others fail to satisfy the complex requirements of tissues in culture. We have examined the use of different types of bioreactors in regenerative medicine and evaluated the application of bioreactors in the realization of emerging cellular therapies.