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

The Autologous Hematopoietic Stem Cells Transplantation Combination-Based Chimeric Antigen Receptor T-Cell Therapy Improves Outcomes of Relapsed/Refractory Central Nervous System B-Cell Lymphoma

OBJECTIVE

The objective is to explore the effectiveness and safety of CAR T-cell therapy in advanced relapsed/refractory central nervous system B-cell lymphoma and compare the impact of autologous stem cell transplantation (ASCT) plus CAR T-cell therapy versus sequential CART therapy on the survival of patients.

METHODS

The retrospective analysis was based on the data of 17 patients with advanced relapsed/refractory central nervous system B-cell lymphoma. Bridging chemotherapy was applied before CAR T-cell infusion to further reduce the tumor burden. For patients with autologous hematopoietic stem cell successful collection, CD19/20/22CAR T-cell immunotherapy following ASCT was performed with the thiotepa-containing conditioning regimen, while sequential CD19/CD20/CD22CAR T-cell therapy was applied. For lymphodepletion, patients received bendamustine or fludarabine monotherapy or fludarabine combined with cyclophosphamide pre-CART-cell infusion.

RESULTS

Out of the 17 patients, 8 completed ASCT plus CART cell therapy, while 9 patients completed CART cell alone therapy. In efficacy assessment at 3 months after infusion, the objective response rate (ORR) was 12/17 (71%) and the complete response rate (CRR) was 11/17 (65%). The CRR of the ASCT group and non-ASCT was 100% and 44.4%, respectively (P < 0.01). The median progression-free survival was 16.3 (2.6-24.5) months, and the median overall survival was 19.3 (6-24.5) months. Patients who underwent ASCT plus CART cell therapy had significantly longer PFS (P < 0.01) and OS (P < 0.01). Grade 3 or higher immune effector cell-associated neurologic toxicity syndrome (≥grade 3 ICANS) and cytokine release syndrome (≥grade 3 CRS) events occurred in 29% and 41% of the patients, respectively. No treatment-related death occurred.

CONCLUSION

The CAR T-cell therapy could augment its efficacy in the treatment of advanced relapsed/refractory CNS B-cell lymphoma, while ASCT in combination with CART can induce durable responses and OS with a manageable side effect.

The role of allogeneic transplant for adult Ph+ ALL in CR1 with complete molecular remission: a retrospective analysis

Historically, Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has been associated with poor outcomes, and allogeneic hematopoietic cell transplantation (allo-HCT) is recommended in first complete remission (CR1). However, in the tyrosine kinase inhibitor (TKI) era, rapid attainment of a complete molecular remission (CMR) is associated with excellent outcomes without allo-HCT, suggesting transplant may not be required for these patients. To test this hypothesis, we retrospectively identified adult patients with Ph+ ALL treated with induction therapy, including TKIs, and attained CMR within 90 days of diagnosis at 5 transplant centers in the United States. We compared outcomes of those who did and did not receive allo-HCT in first remission. We identified 230 patients (allo-HCT: 98; non-HCT: 132). The allo-HCT cohort was younger with better performance status. On multivariable analysis (MVA), allo-HCT was not associated with improved overall survival (adjusted hazard ratio [aHR]: 1.05; 95% CI, 0.63-1.73) or relapse-free survival (aHR: 0.86; 95% CI, 0.54-1.37) compared with non-HCT treatment. Allo-HCT was associated with a lower cumulative incidence of relapse (aHR: 0.32; 95% CI, 0.17-0.62) but higher non-relapse mortality (aHR: 2.59; 95% CI, 1.37-4.89). Propensity score matching analysis confirmed results of MVA. Comparison of reduced-intensity HCT to non-HCT showed no statistically significant difference in any of the above endpoints. In conclusion, adult patients with Ph+ ALL who achieved CMR within 90 days of starting treatment did not derive a survival benefit from allo-HCT in CR1 in this retrospective study.

Pericardial Relapse of Acute Lymphoblastic Leukemia (ALL)

Acute lymphoblastic leukemia (ALL) is a neoplasm of the B cell or T cell. Diagnosis is made by peripheral blood smear and bone marrow biopsy. Those with relapse/measurable residual disease (MRD) present with fever, weakness, fatigue, and easy bruising due to bone marrow infiltration (Kantarjian et al., 2017). A 59-year-old male with history of relapsed acute lymphoblastic leukemia and allogeneic stem cell transplant presented to the Emergency Department (ED) multiple times with shortness of breath. 2D Echo revealed recurrent pericardial effusion. His MRD was discovered in the pericardium. He underwent the creation of a pericardial window with cytology and culture which confirmed B cell lymphoblastic leukemia/lymphoma, consistent with relapsed disease. We present a case of a patient with B-ALL and MRD who presented with symptoms of shortness of breath. His MRD was discovered not in the bone marrow, but in the pericardium.

Biologic Assignment Trial of Reduced-Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients 50-75 Years of Age With Advanced Myelodysplastic Syndrome

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy for myelodysplastic syndromes (MDS), although it is infrequently offered to older patients. The relative benefits of HCT over non-HCT therapy in older patients with higher-risk MDS have not been defined.

METHODS

We conducted a multicenter biologic assignment trial comparing reduced-intensity HCT to hypomethylating therapy or best supportive care in subjects 50-75 years of age with intermediate-2 or high-risk de novo MDS. The primary outcome was overall survival probability at 3 years. Between January 2014 and November 2018, we enrolled 384 subjects at 34 centers. Subjects were assigned to the Donor or No-Donor arms according to the availability of a matched donor within 90 days of study registration.

RESULTS

The median follow-up time for surviving subjects was 34.2 months (range: 2.3-38 months) in the Donor arm and 26.9 months (range: 2.4-37.2 months) in the No-Donor arm. In an intention-to-treat analysis, the adjusted overall survival rate at 3 years in the Donor arm was 47.9% (95% CI, 41.3 to 54.1) compared with 26.6% (95% CI, 18.4 to 35.6) in the No-Donor arm (P = .0001) with an absolute difference of 21.3% (95% CI, 10.2 to 31.8). Leukemia-free survival at 3 years was greater in the Donor arm (35.8%; 95% CI, 29.8 to 41.8) compared with the No-Donor arm (20.6%; 95% CI, 13.3 to 29.1; P = .003). The survival benefit was seen across all subgroups examined.

CONCLUSION

We observed a significant survival advantage in older subjects with higher-risk MDS who have a matched donor identified and underwent reduced-intensity HCT, when compared with those without a donor. HCT should be included as an integral part of MDS management plans in fit older adults with higher-risk MDS.

Systematic Reviews in Hematopoietic Cell Transplantation and Cellular Therapy: Considerations and Guidance from the American Society for Transplantation and Cellular Therapy, European Society for Blood and Marrow Transplantation, and Center for International Blood and Marrow Transplant Research Late Effects and Quality of Life Working Committee

Systematic reviews apply rigorous methodologies to address a prespecified, clearly formulated clinical research question. The conclusion that results is often cited to more robustly inform decision making by clinicians, third-party payers, and managed care organizations about the clinical question of interest. Although systematic reviews provide a rigorous standard, they may be infeasible when the task is to create general disease-focused guidelines comprising multiple clinical practice questions versus a single major clinical practice question. Collaborating transplantation and cellular therapy society committees also recognize that the quantity and or quality of reference sources may be insufficient for a meaningful systematic review. As the conduct of systematic reviews has evolved over time in terms of grading systems, reporting requirements, and use of technology, here we provide current guidance on methodologies, resources for reviewers, and approaches to overcome challenges in conducting systematic reviews in transplantation and cellular therapy.

Inferior outcomes with reduced intensity conditioning followed by allogeneic hematopoietic cell transplantation in fit individuals with acute lymphoblastic leukemia: a Canadian single-center study and a comparison to registry data

Allogeneic hematopoietic cell transplantation (HCT) can offer cure to some patients with acute lymphoblastic leukemia (ALL). It remains unclear how conditioning intensity affects transplant outcomes in ALL. In this retrospective study, we compared outcomes between 27 patients <60 who received reduced intensity conditioning (RIC) at Princess Margaret Hospital Cancer Center (PMCC) and 226 Cell Therapy Transplant Canada (CTTC) age-matched controls who received myeloablative conditioning (MAC) between 2007 and 2018. Compared to CTTC patients, PMCC patients had an inferior 2-y OS: 0.29 (95% CI: 0.11-0.49) vs 0.63 (0.56-0.70), HR = 2.10 (1.23-3.55), p = 0.006, higher TRM: 0.41 (0.22-0.60) vs 0.24 (0.18-0.30), HR = 2.00 (1.05-3.81), p = 0.04 and a trend toward increased risk of relapse: 0.36 (0.17-0.56) versus 0.17 (0.12-0.22), HR = 1.72 (0.82-3.62), p = 0.15. In multivariate analysis, RIC and the use of T-cell depletion (TCD) were associated with inferior OS. In ALL patients <60, the use of RIC with TCD is associated with inferior allogeneic HCT outcomes.

Systematic reviews in hematopoietic cell transplantation and cellular therapy: considerations and guidance from the American Society for Transplantation and Cellular Therapy, European Society for Blood and Marrow Transplantation, and the Center for International Blood and Marrow Transplant Research late effects and quality of life working committee

Systematic reviews apply rigorous methodologies to address a pre-specified, clearly formulated clinical research question. The conclusion that results is often cited to more robustly inform decision-making by clinicians, third-party payers and managed care organizations about the clinical question of interest. While systematic reviews provide a rigorous standard, they may be unfeasible when the task is to create general disease-focused guidelines comprised of multiple clinical practice questions versus a single major clinical practice question. Collaborating transplantation and cellular therapy societal committees also recognize that the quantity and or quality of reference sources may be insufficient for a meaningful systematic review. As the conduct of systematic reviews has evolved over time in terms of grading systems, reporting requirements and use of technology, here we provide current guidance in methodologies, resources for reviewers, and approaches to overcome challenges in conducting systematic reviews in transplantation and cellular therapy.

Comparative study on allogeneic with autologous hematopoietic stem cell transplantation in adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia in the era of TKIs: a systematic review and meta-analysis

In the era of tyrosine kinase inhibitors (TKIs), allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recommended as a standard approach for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) achieving complete remission (CR). However, the role of autologous hematopoietic stem cell transplantation (auto-HSCT) in adult patients achieving complete molecular remission (CMR) is an alternative, less toxic treatment options, especially for the patients who lack suitable donors and are unfit for allo-HSCT. Thus, we conducted a systematic review and meta-analysis to compare the efficacy of allo-HSCT and auto-HSCT for the treatment of adult patients with Ph+ ALL. We searched the PubMed, Embase, Scopus, and Cochrane Library for studies published before June 2019 without language restriction. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for overall survival (OS) and relapse-free survival (RFS) and odds ratios (ORs) and 95% CIs for relapse rate (RR) and treatment-related mortality (TRM). Four prospective studies and one retrospective study were included with a total of 810 patients. We found auto-HSCT was superior to allo-HSCT in OS (HR = 1.42, 95% CI: 1.06-1.91, P = 0.02), and there was no difference between allo-HSCT and auto-HSCT for RFS (HR = 1.10, 95% CI: 0.86-1.40, P = 0.44) and RR (OR = 0.53, 95% CI: 0.22-1.26, P = 0.15). The risk of TRM for patients undergoing allo-HSCT was significantly higher than that of the patients who received auto-HSCT (OR = 5.06, 95% CI: 1.03-24.75, P = 0.05). Our meta-analysis shows that auto-HSCT may be an attractive and alternative treatment option for adult Ph+ ALL patients achieving CMR, with similar or better outcomes than allo-HSCT in the era of TKIs.

Debate: Transplant Is Still Necessary in the Era of Targeted Cellular Therapy for Acute Lymphoblastic Leukemia

Despite high complete remission (CR) rates, relapse remains a significant problem among subsets of patients with B acute lymphoblastic leukemia (ALL), and is associated with poor prognosis. The recent Food and Drug Administration approval of highly effective immunotherapies for B-lineage ALL (B-ALL), blinatumomab, inotuzumab ozogamicin, and tisagenlecleucel, a chimeric antigen receptor (CAR) modified T-cell therapy, targeting CD19, or CD22, have dramatically changed the therapeutic landscape for the treatment of B-ALL, resulting in high rates of deep and durable remissions. Therefore, there is now debate regarding the role of allogeneic hematopoietic cell transplantation (HCT) in this new landscape. Herein, we review these novel agents, and discuss the sequence of therapy, including allogeneic HCT in B-ALL.

Indications for Hematopoietic Cell Transplantation and Immune Effector Cell Therapy: Guidelines from the American Society for Transplantation and Cellular Therapy

The American Society for Transplantation and Cellular Therapy (ASTCT) published its first white paper on indications for autologous and allogeneic hematopoietic cell transplantation (HCT) in 2015. It was identified at the time that periodic updates of indications would be required to stay abreast with state of the art and emerging indications and therapy. In recent years the field has not only seen an improvement in transplantation technology, thus widening the therapeutic scope of HCT, but additionally a whole new treatment strategy using modified immune effector cells, including chimeric antigen receptor T cells and engineered T-cell receptors, has emerged. The guidelines review committee of the ASTCT deemed it optimal to update the ASTCT recommendations for indications for HCT to include new data and to incorporate indications for immune effector cell therapy (IECT) where appropriate. The guidelines committee established a multiple stakeholder task force consisting of transplant experts, payer representatives, and a patient advocate to provide guidance on indications for HCT and IECT. This article presents the updated recommendations from the ASTCT on indications for HCT and IECT. Indications for HCT/IECT were categorized as (1) Standard of care, where indication is well defined and supported by evidence; (2) Standard of care, clinical evidence available, where large clinical trials and observational studies are not available but have been shown to be effective therapy; (3) Standard of care, rare indication, for rare diseases where demonstrated effectiveness exists but large clinical trials and observational studies are not feasible; (4) Developmental, for diseases where preclinical and/or early-phase clinical studies show HCT/IECT to be a promising treatment option; and (5) Not generally recommended, where available evidence does not support the routine use of HCT/IECT. The ASTCT will continue to periodically review these guidelines and update them as new evidence becomes available.

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.

Inotuzumab ozogamicin versus standard of care in relapsed or refractory acute lymphoblastic leukemia: Final report and long-term survival follow-up from the randomized, phase 3 INO-VATE study

BACKGROUND

Inotuzumab ozogamicin (InO) is an antibody-drug conjugate used for adults with relapsed/refractory B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). The INotuzumab Ozogamicin trial to inVestigAte Tolerability and Efficacy (INO-VATE) previously reported improved outcomes with InO versus standard-of-care (SoC) chemotherapy. This article reports the final INO-VATE results (≥2 years of follow-up) and additional analyses of patient characteristics associated with improved outcomes.

METHODS

Between August 27, 2012, and January 4, 2015, this multicenter, parallel, open-label, phase 3 trial randomized 326 adults with relapsed/refractory ALL to InO (n = 164) or SoC (n = 162); 307 received 1 or more doses of the study drug (164 in the InO arm and 143 in the SoC arm).

RESULTS

The complete remission (CR)/complete remission with incomplete hematologic recovery (CRi) rate was higher with InO versus SoC (73.8% vs 30.9%; 1-sided P < .0001), with consistent CR/CRi rates across patient subgroups. The median overall survival (OS) was 7.7 months with InO and 6.2 months with SoC, with 2-year OS rates of 22.8% and 10.0%, respectively (overall hazard ratio, 0.75; 97.5% confidence interval [CI], 0.57-0.99; 1-sided P = .0105). The predictors of OS with InO were the best minimal residual disease status, baseline platelet count, duration of first remission, achievement of CR/CRi, and follow-up hematopoietic stem cell transplantation (HSCT; all 2-sided P values < .05). More InO arm patients proceeded directly to HSCT after achieving CR/CRi before any follow-up induction therapy (39.6% [95% CI, 32.1%-47.6%] vs 10.5% [6.2%-16.3%]; 1-sided P < .0001). The most frequent all-grade and grade 3 or higher adverse events in both arms were hematologic. Veno-occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS) was more frequent with InO (23 of 164 [14.0%] vs 3 of 143 [2.1%]).

CONCLUSIONS

In patients with relapsed/refractory BCP ALL in INO-VATE, InO was associated with a greater likelihood of CR/CRi across key patient subgroups, and it served as a bridge to HSCT. Potential VOD/SOS risk factors must be considered when InO treatment decisions are being made.

Improving hematopoietic recovery through modeling and modulation of the mesenchymal stromal cell secretome

BACKGROUND

Efficient and sustained hematopoietic recovery after hematopoietic stem cell or bone marrow transplantation is supported by paracrine signaling from specific subpopulations of mesenchymal stromal cells (MSCs). Here, we considered whether in vitro mechanopriming of human MSCs could be administered to predictively and significantly improve in vivo hematopoietic recovery after irradiation injury.

METHODS

First, we implemented regression modeling to identify eight MSC-secreted proteins that correlated strongly with improved rescue from radiation damage, including hematopoietic recovery, in a murine model of hematopoietic failure. Using these partial least squares regression (PLSR) model parameters, we then predicted recovery potential of MSC populations that were culture expanded on substrata of varying mechanical stiffness. Lastly, we experimentally validated these predictions using an in vitro co-culture model of hematopoiesis and using new in vivo experiments for the same irradiation injury model used to generate survival predictions.

RESULTS

MSCs grown on the least stiff (elastic moduli ~ 1 kPa) of these polydimethylsiloxane (PDMS) substrata secreted high concentrations of key proteins identified in regression modeling, at concentrations comparable to those secreted by minor subpopulations of MSCs shown previously to be effective in supporting such radiation rescue. We confirmed that these MSCs expanded on PDMS could promote hematopoiesis in an in vitro co-culture model with hematopoietic stem and progenitor cells (HSPCs). Further, MSCs cultured on PDMS of highest stiffness (elastic moduli ~ 100 kPa) promoted expression of CD123+ HSPCs, indicative of myeloid differentiation. Systemic administration of mechanoprimed MSCs resulted in improved mouse survival and weight recovery after bone marrow ablation, as compared with both standard MSC expansion on stiffer materials and with biophysically sorted MSC subpopulations. Additionally, we observed recovery of white blood cells, platelets, and red blood cells, indicative of complete recovery of all hematopoietic lineages.

CONCLUSIONS

These results demonstrate that computational techniques to identify MSC biomarkers can be leveraged to predict and engineer therapeutically effective MSC phenotypes defined by mechanoprimed secreted factors, for translational applications including hematopoietic recovery.

Acute lymphoblastic leukaemia with osteolytic bone lesions: diagnostic dilemma

A previously healthy 37-year-old man presented with a 10-month history of intractable back pain. On examination, there was tenderness to palpation along lower thoracic and lumbar spine. Complete blood count showed mild anaemia but was otherwise unremarkable. Imaging studies revealed compression deformities with multiple osteolytic lesions involving multiple levels of the thoracic and lumbar spine. Bone marrow aspiration and biopsy were performed and demonstrated blast cells involving 80% of the bone marrow cellularity. Findings on flow cytometry were consistent with B-lymphoblastic leukaemia. He was subsequently started on hyper-CVAD (fractionated cyclophosphamide, vincristine, Adriamycin and dexamethasone) induction chemotherapy.

Phenotyping and Target Expression Profiling of CD34+/CD38- and CD34+/CD38+ Stem- and Progenitor cells in Acute Lymphoblastic Leukemia

Leukemic stem cells (LSCs) are an emerging target of curative anti-leukemia therapy. In acute lymphoblastic leukemia (ALL), LSCs frequently express CD34 and often lack CD38. However, little is known about markers and targets expressed in ALL LSCs. We have examined marker- and target expression profiles in CD34⁺/CD38⁻ LSCs in patients with Ph⁺ ALL (n = 22) and Ph⁻ ALL (n = 27) by multi-color flow cytometry and qPCR. ALL LSCs expressed CD19 (B4), CD44 (Pgp-1), CD123 (IL-3RA), and CD184 (CXCR4) in all patients tested. Moreover, in various subgroups of patients, LSCs also displayed CD20 (MS4A1) (10/41 = 24%), CD22 (12/20 = 60%), CD33 (Siglec-3) (20/48 = 42%), CD52 (CAMPATH-1) (17/40 = 43%), IL-1RAP (13/29 = 45%), and/or CD135 (FLT3) (4/20 = 20%). CD25 (IL-2RA) and CD26 (DPPIV) were expressed on LSCs in Ph⁺ ALL exhibiting BCR/ABL1_p210, whereas in Ph⁺ ALL with BCR/ABL1_p190, LSCs variably expressed CD25 but did not express CD26. In Ph⁻ ALL, CD34⁺/CD38⁻ LSCs expressed IL-1RAP in 6/18 patients (33%), but did not express CD25 or CD26. Normal stem cells stained negative for CD25, CD26 and IL-1RAP, and expressed only low amounts of CD52. In xenotransplantation experiments, CD34⁺/CD38⁻ and CD34⁺/CD38⁺ cells engrafted NSG mice after 12–20 weeks, and targeting with antibodies against CD33 and CD52 resulted in reduced engraftment. Together, LSCs in Ph⁺ and Ph⁻ ALL display unique marker- and target expression profiles. In Ph⁺ ALL with BCR/ABL1_p210, the LSC-phenotype closely resembles the marker-profile of CD34⁺/CD38⁻ LSCs in chronic myeloid leukemia, confirming the close biologic relationship of these neoplasms. Targeting of LSCs with specific antibodies or related immunotherapies may facilitate LSC eradication in ALL.

Anti-thymocyte globulin improves survival free from relapse and graft-versus-host disease after allogeneic peripheral blood stem cell transplantation in patients with Philadelphia-negative acute lymphoblastic leukemia: An analysis by the Acute Leukemia Working Party of the EBMT

BACKGROUND

Mobilized peripheral blood stem cells are currently the predominant source of grafts for allogeneic transplantation (allogeneic peripheral blood stem cell transplantation [allo-PBSCT]), although, in comparison with bone marrow, their use is associated with an increased risk of chronic graft-versus-host disease (cGVHD). Attempts to reduce the incidence of cGVHD include the addition of anti-thymocyte globulin (ATG) to the pretransplant conditioning regimen.

METHODS

The goal of this retrospective study was to analyze the effect of ATG on allo-PBSCT outcomes for adults with Philadelphia-negative acute lymphoblastic leukemia (Ph-neg ALL). The primary endpoint was survival free from relapse, grade 3 to 4 acute graft-versus-host disease (aGVHD), and cGVHD (ie, graft-versus-host disease-free/relapse-free survival [GRFS]). Nine-hundred twenty-four patients who underwent unmanipulated allo-PBSCT in their first complete remission between 2007 and 2016 were included. ATG was used in 97 of the 494 transplants from matched sibling donors (20%) and in 307 of the 430 transplants from human leukocyte antigen-matched (8 of 8 loci) unrelated donors (71%).

RESULTS

The use of ATG was an independent factor for an improved chance of GRFS (hazard ratio [HR], 0.70; P = .0009). Furthermore, it was associated with a reduced risk of both grade 2 to 4 (HR, 0.66; P = .005) and grade 3 to 4 aGVHD (HR, 0.58; P = .03). Similarly, its addition reduced the incidence of both total (HR, 0.45; P < 10^-5 ) and extensive cGVHD (HR, 0.30; P < 10^-5 ) as well as nonrelapse mortality (HR, 0.58; P = .01). No significant effect was found with respect to leukemia-free or overall survival. However, an increased risk of relapse was noted for those who received ATG (HR, 1.40; P = .04).

CONCLUSIONS

Patients with Ph-neg ALL treated with allo-PBSCT benefit from the use of ATG in terms of improved GRFS. Its use may, therefore, be considered in this setting. Cancer 2018;124:2523-33. © 2018 American Cancer Society.

CD20 expression sub-stratifies standard-risk patients with B cell precursor acute lymphoblastic leukemia

Patients with standard-risk adult acute lymphoblastic leukemia (ALL) treated with chemotherapy do not have satisfactory outcomes. To more precisely classify ALL patients and optimize treatment, we re-evaluated the risk stratification system by examining CD20 expression and other classic risk factors at diagnosis. We retrospectively analyzed response to induction chemotherapy of 217 consecutive patients with newly diagnosed Philadelphia-negative B cell precursor-ALL. Survival analyses were conducted for the 136 patients who were intended to be treated with chemotherapy alone. Among the 217 patients, 69 (31.8%) were considered standard risk based on age <35 years, white blood cell count <30 × 10⁹/L, absence of central nervous system involvement, and high-risk cytogenetic abnormalities. Seventy-four patients (34.1%) expressed CD20 on ≥20% of leukemia blasts and were considered CD20 positive. We found that fewer CD20-positive than CD20-negative patients achieved durable first complete responses (CR1 ≥3 months) (81.1% vs. 94.9%, P=0.002). Within the standard-risk group, more CD20-negative than CD20-positive patients achieved CR (100% vs. 83.3%, P=0.003) and durable CR1 (100% vs. 82.4%, P=0.014). For patients in the CD20-negative standard-risk, CD20-positive standard-risk, CD20-negative high-risk, and CD20-positive high-risk groups, the 3-year cumulative incidence of relapse was 42.6%, 70.0%, 59.3%, and 69.5%, respectively (P=0.118); the 3-year disease-free survival rates were 52.1%, 0%, 20.7%, and 13.7%, respectively (P=0.006); and the 3-year overall survival rates were 55.8%, 13.8%, 23.6%, and 16.9%, respectively (P=0.006). Our results suggest that patients with CD20-negative standard-risk B cell precursor-ALL have favorable prognosis compared with CD20-positive standard-risk or CD20-negative or -positive high-risk patients. CD20-positive standard-risk ALL patients may need other therapeutic modalities bridging to allogeneic hematopoietic stem cell transplantation.

Unmanipulated haploidentical stem cell transplantation in adults with acute lymphoblastic leukemia: a study on behalf of the Acute Leukemia Working Party of the EBMT

Background

Allogenic hematopoietic stem cell transplantation (allo-SCT) is the most effective post-remission treatment for adults with high-risk acute lymphoblastic leukemia (ALL). The aim of the study was to analyze results of unmanipulated haploidentical allo-SCT (haplo-SCT) for adults with ALL and to identify prognostic factors.

Methods

We performed a retrospective analysis on 208 adults transplanted in EBMT centers from 2007 to 2014.

Results

Median age at haplo-SCT was 32 years and median follow-up, 31 months. Forty-four percent of the patients were in first complete remission (CR1). Stem cell source was the bone marrow (BM) for 43% and peripheral blood (PB) for 57% of patients. Myeloablative conditioning (MAC) was used for 66% and reduced intensity regimen (RIC) for 34% of patients. GVHD prophylaxis was based on post-transplant cyclophosphamide (PT-Cy) for 118 (57%) or on anti-thymocyte-globulin (ATG) for 90 (43%) plus standard prophylaxis. One hundred eighty-four (92%) patients achieved engraftment. Cumulative incidence (CI) of grade II–IV acute-graft-versus-host-disease (GVHD) was 31%, grade III–IV 11%, and chronic GVHD 29%. Non-relapse mortality (NRM) and relapse-incidence (RI) were 32 and 37%, respectively. Overall survival (OS), leukemia-free survival (LFS), and GVHD-free, relapse-free-survival (GRFS) at 3 years were 33, 31, and 26%. For patients in CR1, OS, LFS, and GRFS were 52, 47, and 40%, respectively. Disease status was the main factor associated with transplant outcomes. Use of BM was independently associated with improvement in NRM, acute GVHD, GRFS, LFS, and OS.

Conclusions

Unmanipulated haplo-SCT may be considered a valid option for adult patients with high-risk ALL lacking HLA identical donor preferably in early disease status.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0480-5) contains supplementary material, which is available to authorized users.

Clofarabine Plus Busulfan is an Effective Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Acute Lymphoblastic Leukemia: Long-Term Study Results

We investigated the long-term safety and disease control data obtained with i.v. busulfan (Bu) combined with clofarabine (Clo) in patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). A total of 107 patients, median age 38 years (range, 19 to 64 years) received a matched sibling donor (n = 52) or matched unrelated donor (n = 55) transplant for ALL in first complete remission (n = 62), second complete remission (n = 28), or more advanced disease (n = 17). Nearly one-half of the patients had a high-risk cytogenetic profile as defined by the presence of t(9;22) (n = 34), t(4;11) (n = 4), or complex cytogenetics (n = 7). Clo 40 mg/m² was given once daily, with each dose followed by pharmacokinetically dosed Bu infused over 3 hours daily for 4 days, followed by hematopoietic cell infusion after 2 days of rest. The Bu dose was based on the drug clearance as determined by a test Bu dose of 32 mg/m². The target daily area under the curve was 5500 µmol/min for patients aged <60 years and 4000 µmol/min for patients aged >59 years. With a median follow-up of 3.3 years among surviving patients (range, 1 to 5.8 years), the 2-year progression-free survival (PFS) for patients undergoing HSCT in first complete remission (CR1), second complete remission (CR2), or more advanced disease was 62%, 34%, and 35%, respectively. The regimen was well tolerated, with nonrelapse mortality (NRM) of 10% at 100 days and 31% at 2 years post-HSCT. The incidence of grade II-IV and III-IV acute graft-versus-host disease (GVHD) was 35% and 10%, respectively; 18% patients developed extensive chronic GVHD. The 2-year overall survival (OS) for patients undergoing HSCT in CR1, CR2, or more advanced disease was 70%, 57%, and 35%, respectively. Among 11 patients aged >59 years treated with reduced-dose Bu in CR1 (n = 7) or CR2 (n = 4), 4 remain alive and disease-free, with a median follow-up of 2.6 years (range, 2 to 4.7 years). Only the presence of minimal residual disease at the time of transplantation was associated with significantly worse PFS and OS in multivariate analysis. Our data indicate that the Clo-Bu combination provides effective disease control while maintaining a favorable safety profile. OS and NRM rates compare favorably with those for traditional myeloablative total body irradiation-based conditioning regimens.

Retrospective analysis of adult patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic cell transplantation: A multicenter experience of daily practice

Compared to pediatric age group, the prognosis of adult acute lymphoblastic leukemia (ALL) is still dismal even in patients receiving allogeneic hematopoietic cell transplantation (AHCT). We retrospectively analyzed 205 adults (male: 122; female: 83) with ALL who underwent AHCT. Median age of patients was 28 (18-59). Fifty-two patients had Ph(+) ALL. The estimated relapse-free and overall survival (OS) of the study cohort at 1, 2 and 3 years were 52.3%/63.9%, 42.9%/49.5% and 39.9%/45.6%, respectively. On multivariate analysis, first complete remission at the time of AHCT, TBI-based conditioning and development of chronic graft-versus-host disease were only factors, which were significantly associated with prolonged OS.

Indications for Autologous and Allogeneic Hematopoietic Cell Transplantation: Guidelines from the American Society for Blood and Marrow Transplantation

Approximately 20,000 hematopoietic cell transplantation (HCT) procedures are performed in the United States annually. With advances in transplantation technology and supportive care practices, HCT has become safer, and patient survival continues to improve over time. Indications for HCT continue to evolve as research refines the role for HCT in established indications and identifies emerging indications where HCT may be beneficial. The American Society for Blood and Marrow Transplantation (ASBMT) established a multiple-stakeholder task force consisting of transplant experts, payer representatives, and a patient advocate to provide guidance on "routine" indications for HCT. This white paper presents the recommendations from the task force. Indications for HCT were categorized as follows: (1) Standard of care, where indication for HCT is well defined and supported by evidence; (2) Standard of care, clinical evidence available, where large clinical trials and observational studies are not available but HCT has been shown to be effective therapy; (3) Standard of care, rare indication, for rare diseases where HCT has demonstrated effectiveness but large clinical trials and observational studies are not feasible; (4) Developmental, for diseases where preclinical and/or early phase clinical studies show HCT to be a promising treatment option; and (5) Not generally recommended, where available evidence does not support the routine use of HCT. The ASBMT will periodically review these guidelines and will update them as new evidence becomes available.

IgH-V(D)J NGS-MRD measurement pre- and early post-allotransplant defines very low- and very high-risk ALL patients

Positive detection of minimal residual disease (MRD) by multichannel flow cytometry (MFC) prior to hematopoietic cell transplantation (HCT) of patients with acute lymphoblastic leukemia (ALL) identifies patients at high risk for relapse, but many pre-HCT MFC-MRD negative patients also relapse, and the predictive power MFC-MRD early post-HCT is poor. To test whether the increased sensitivity of next-generation sequencing (NGS)-MRD better identifies pre- and post-HCT relapse risk, we performed immunoglobulin heavy chain (IgH) variable, diversity, and joining (V[D]J) DNA sequences J NGS-MRD on 56 patients with B-cell ALL enrolled in Children's Oncology Group trial ASCT0431. NGS-MRD predicted relapse and survival more accurately than MFC-MRD (P < .0001), especially in the MRD negative cohort (relapse, 0% vs 16%; P = .02; 2-year overall survival, 96% vs 77%; P = .003). Post-HCT NGS-MRD detection was better at predicting relapse than MFC-MRD (P < .0001), especially early after HCT (day 30 MFC-MRD positive relapse rate, 35%; NGS-MRD positive relapse rate, 67%; P = .004). Any post-HCT NGS positivity resulted in an increase in relapse risk by multivariate analysis (hazard ratio, 7.7; P = .05). Absence of detectable IgH-V(D)J NGS-MRD pre-HCT defines good-risk patients potentially eligible for less intense treatment approaches. Post-HCT NGS-MRD is highly predictive of relapse and survival, suggesting a role for this technique in defining patients early who would be eligible for post-HCT interventions. The trial was registered at www.clinicaltrials.gov as #NCT00382109.

How I treat adults with relapsed or refractory Philadelphia chromosome-negative acute lymphoblastic leukemia

The long-term prognosis of adult patients with relapsed Philadelphia chromosome-negative acute lymphoblastic lymphoma (ALL) is poor. Allogeneic stem cell transplant in second remission is the only curative approach and is the goal when feasible. There is no standard chemotherapy regimen for relapsed disease, although a few agents are approved for use in this setting. The bispecific CD19-directed CD3 T-cell engager, blinatumomab, has recently been granted accelerated approval by the US Food and Drug Administration for relapsed or refractory disease of B-cell lineage. For patients with relapsed T-cell ALL, nelarabine is available. Liposomal vincristine is also approved for relapsed disease. When selecting combination chemotherapy salvage options, evaluation of the prior treatment and timing of relapse informs treatment decisions. Monoclonal and cellular investigational therapies are quite promising and should be explored in the appropriate patient.

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.

Alternative donor transplantation for adults with acute leukemia

Allogeneic hematopoietic cell transplantation (HCT) from a matched related donor (MRD) is the preferred therapy for many adults with acute leukemia. Yet most patients do not have matched siblings, and the numbers who do will continue to drop as the average number of children per couple in the United States continues to decline. Recent reports show little difference in the outcomes of matched related and matched unrelated transplants for acute leukemia. Additionally, survival rates at 3-5 years after transplant appear to be generally similar following matched related, matched unrelated, single antigen mismatched unrelated, double cord blood and, perhaps even after haplo-identical transplants. Nevertheless, there are differences between stem cell sources that should be considered in the choice of donor. The following review provides some perspective on the identification of the best stem cell sources for patients who do not have matches within their families.

Managing chemotherapy-related cardiotoxicity in survivors of childhood cancers

In the US, children diagnosed with cancer are living longer, but not without consequences from the same drugs that cured their cancer. In these patients, cardiovascular disease is the leading cause of non-cancer-related morbidity and mortality. Although this review focuses on anthracycline-related cardiomyopathy in childhood cancer survivors, the global lifetime risk of other cardiovascular diseases such as atherosclerosis, arrhythmias and intracardiac conduction abnormalities, hypertension, and stroke also are increased. Besides anthracyclines, newer molecularly targeted agents, such as vascular endothelial growth factor receptor and tyrosine kinase inhibitors, also have been associated with acute hypertension, cardiomyopathy, and increased risk of ischemic cardiac events and arrhythmias, and are summarized here. This review also covers other risk factors for chemotherapy-related cardiotoxicity (including both modifiable and non-modifiable factors), monitoring strategies (including both blood and imaging-based biomarkers) during and following cancer treatment, and discusses the management of cardiotoxicity (including prevention strategies such as cardioprotection by use of dexrazoxane).

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.

Comparison of chimerism and minimal residual disease monitoring for relapse prediction after allogeneic stem cell transplantation for adult acute lymphoblastic leukemia

Little data are available on the relative merits of chimerism and minimal residual disease (MRD) monitoring for relapse prediction after allogeneic hematopoietic stem cell transplantation (HCT). We performed a retrospective analysis of serial chimerism assessments in 101 adult HCT recipients with acute lymphoblastic leukemia (ALL) and of serial MRD assessments in a subgroup of 22 patients. All patients had received myeloablative conditioning. The cumulative incidence of relapse was significantly higher in the patients with increasing mixed chimerism (in-MC) compared with those with complete chimerism, low-level MC, and decreasing MC, but the sensitivity of in-MC detection with regard to relapse prediction was only modest. In contrast, MRD assessment was highly sensitive and specific. Patients with MRD positivity after HCT had the highest incidence of relapse among all prognostic groups analyzed. The median time from MRD positivity to relapse was longer than the median time from detection of in-MC, but in some cases in-MC preceded MRD positivity. We conclude that MRD assessment is a powerful prognostic tool that should be included in the routine post-transplantation monitoring of patients with ALL, but chimerism analysis may provide additional information in some cases. Integration of these tools and clinical judgment should allow optimal decision making with regard to post-transplantation therapeutic interventions.

Treating relapsed or refractory Philadelphia chromosome-negative acute lymphoblastic leukemia: liposome-encapsulated vincristine

Acute lymphoblastic leukemia (ALL) remains a disease with poor outcomes in adults. While induction chemotherapy achieves a complete remission in almost 90% of patients, the majority will relapse and die of their disease. Relapsed ALL is associated with a high reinduction mortality and chemotherapy resistance, with allogeneic hematopoietic stem cell transplantation offering the only therapy with curative potential. However, there is no efficacious and well tolerated standard regimen accepted as a “bridge” to allogeneic stem cell transplantation or as definitive treatment for patients who are not transplant candidates. Vincristine is an active drug in patients with ALL, but its dose intensity is limited by neurotoxicity, and its full potential as an anticancer drug is thus not realized. Encapsulation of vincristine into sphingomyelin and cholesterol nanoparticle liposomes facilitates dose-intensification and densification to enhanced target tissues with reduced potential for toxicity. Vincristine sulfate liposome injection (VSLI) is associated with significant responses in clinically advanced ALL, and has recently been approved by the US Food and Drug Administration for treatment of relapsed and clinically advanced Philadelphia chromosome-negative ALL. This review provides an overview of the preclinical and clinical studies leading to the approval of VSLI for the treatment of relapsed and refractory ALL, and suggests potential areas of future clinical development.

Novel cellular therapies for leukemia: CAR-modified T cells targeted to the CD19 antigen

The ability of immune-competent donor T cells to mediate a beneficial graft-versus-leukemia (GVL) effect was first identified in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for hematologic malignancies. Unfortunately, with the exception of chronic myelogenous leukemia and EBV-induced lymphoproliferative disease, allo-HSCT GVL lacks the potency to significantly affect disease progression or recurrence in most other hematologic malignancies. The inadequacy of a GVL effect using past approaches is particularly evident in patients with lymphoid malignancies. However, with the advent of improved gene transfer technology, genetically modified tumor-specific immune effectors have extended cellular immunotherapy to lymphoid malignancies. One promising strategy entails the introduction of genes encoding artificial receptors called chimeric antigen receptors (CARs), which redirect the specificity and function of immune effectors. CAR-modified T cells targeted to the B cell-specific CD19 antigen have demonstrated promising results in multiple early clinical trials, supporting further investigation in patients with B-cell cancers. However, disparities in clinical trial design and CAR structure have complicated the discovery of the optimal application of this technology. Recent preclinical studies support additional genetic modifications of CAR-modified T cells to achieve optimal clinical efficacy using this novel adoptive cellular therapy.

Acute lymphoblastic leukemia in first complete remission: temporal trend of outcomes in studies comparing allogeneic transplant with autologous transplant or chemotherapy

In patients with acute lymphoblastic leukemia in first complete remission, several studies have compared allogeneic transplant with autologous transplant or chemotherapy. This material can be the basis for analyzing the temporal trend of outcomes. Our study was designed as a meta-regression focused on temporal trends and based on the endpoint of 5-year leukemia-free survival (5yLFS). Studies in which 5yLFS was determined in a patient group subjected to allogeneic transplant and in a control group (treated with autologous transplant and/or chemotherapy) were eligible for our meta-analysis. A standard literature search was carried out to identify pertinent studies. The results of included studies were submitted to an observational meta-analysis and to a meta-regression focused on two covariates (calendar year in which the study was conducted; percentage of high-risk patients). The endpoint of 5yLFS was separately assessed between allogeneic transplant and autologous transplant or chemotherapy. Our analysis included 14 studies that covered a period (1983 to 1999) in which patients were conditioned only with myeloablative conditioning and not with non-myeloablative ones. In the risk ratio (RR) analysis, the pooled outcome showed a significantly better profile for allogeneic transplantation (RR = 1.42; 95 % confidence interval (CI), 1.22 to 1.65). Separate analysis of the two treatment options found a pooled 5yLFS of 45 % (95 % CI, 38 to 51 %) for allogeneic transplant vs 30 % (95 % CI, 23 to 37 %) for the controls. In meta-regression, the temporal trend analysis revealed that, in patients subjected to allogeneic transplant, the values of 5yLFS showed no significant change over the 16-year interval (p = 0.720); the same stability over time was found in the control group (p = 0.489). On the other hand, the percentage of high-risk patients influenced outcomes in both patient groups at levels of statistical significance (p = 0.014 and p = 0.045 in the allotransplant group and in the controls, respectively). Our results can represent a reference point for future analyses focused on patients treated in more recent years.

Intravenous BU plus Mel: an effective, chemotherapy-only transplant conditioning regimen in patients with ALL

We investigated the administration of i.v. BU combined with melphalan (Mel) in patients with ALL undergoing allogeneic hematopoietic SCT. Forty-seven patients with a median age of 33 years (range 20-61) received a matched sibling (n=27) or matched unrelated donor transplant (n=20) for ALL in first CR (n=26), second CR (n=13), or with more advanced disease (n=8). BU was infused daily for 4 days, either at a fixed dose of 130 mg/m² (5 patients) or using pharmacokinetic (PK) dose adjustment (42 patients), to target an average daily area-under-the-curve (AUC) of 5000 μmol/min, determined by a test dose of i.v. BU at 32 mg/m². This was followed by a rest day, then two daily doses of Mel at 70 mg/m². Stem cells were infused on the following day. The 2-year OS, PFS and non-relapse mortality (NRM) rates were 35% (95% confidence interval (CI), 23-51%), 31% (95% CI, 21-48%) and 37% (95% CI, 23-50%), respectively. Acute NRM at 100 days was favorable at 12% (95% CI, 5-24%); however, the 2-year NRM was significantly higher for patients older than 40 years, 58% vs 20%, mainly due to GVHD.

Novel cellular therapies for leukemia: CAR-modified T cells targeted to the CD19 antigen

The ability of immune-competent donor T cells to mediate a beneficial graft-versus-leukemia (GVL) effect was first identified in the setting of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for hematologic malignancies. Unfortunately, with the exception of chronic myelogenous leukemia and EBV-induced lymphoproliferative disease, allo-HSCT GVL lacks the potency to significantly affect disease progression or recurrence in most other hematologic malignancies. The inadequacy of a GVL effect using past approaches is particularly evident in patients with lymphoid malignancies. However, with the advent of improved gene transfer technology, genetically modified tumor-specific immune effectors have extended cellular immunotherapy to lymphoid malignancies. One promising strategy entails the introduction of genes encoding artificial receptors called chimeric antigen receptors (CARs), which redirect the specificity and function of immune effectors. CAR-modified T cells targeted to the B cell–specific CD19 antigen have demonstrated promising results in multiple early clinical trials, supporting further investigation in patients with B-cell cancers. However, disparities in clinical trial design and CAR structure have complicated the discovery of the optimal application of this technology. Recent preclinical studies support additional genetic modifications of CAR-modified T cells to achieve optimal clinical efficacy using this novel adoptive cellular therapy.

Clofarabine combined with busulfan provides excellent disease control in adult patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation

We investigated the safety and early disease control data for i.v. busulfan (Bu) in combination with clofarabine (Clo) in patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation (SCT). Fifty-one patients (median age, 36 years; range, 20-64 years) received a matched sibling (n = 24), syngeneic (n = 2), or matched unrelated donor transplant (n = 25) for acute lymphoblastic leukemia in first complete remission (n = 30), second complete remission (n = 13), or active disease (n = 8). More than one-half of the patients had a high-risk cytogenetic profile, as defined by the presence of t(9;22) (n = 17), t(4;11) (n = 3), or complex cytogenetics (n = 7). Clo 40 mg/m(2) was given once daily, with each dose followed by pharmacokinetically dosed Bu infused over 3 hours daily for 4 days, followed by hematopoietic SCT 2 days later. The Bu dose was based on drug clearance, as determined by the patient's response to a 32-mg/m(2) Bu test dose given 48 hours before the high-dose regimen. The target daily area under the receiver-operating characteristic curve was 5500 μM/min for patients age <60 years and 4000 μM/min for those age ≥60 years. The regimen was well tolerated, with a 100-day nonrelapse mortality rate of 6%. With a median follow-up of 14 months among surviving patients (range, 6-28 months), the 1-year overall survival, disease-free survival, and nonrelapse mortality rates were 67% (95% confidence interval [CI], 55%-83%), 54% (95% CI, 41%-71%), and 32% (95% CI, 16%-45%), respectively. For patients undergoing SCT in first remission, these respective rates were 74%, 64%, and 25%. Our data indicate that the combination of Clo and Bu provides effective disease control while maintaining a favorable safety profile.

Allogeneic, but not autologous, hematopoietic cell transplantation improves survival only among younger adults with acute lymphoblastic leukemia in first remission: an individual patient data meta-analysis

Hematopoietic cell transplantation (HCT) and prolonged chemotherapy are standard postremission strategies for adult acute lymphoblastic leukemia in first complete remission, but the optimal strategy remains controversial. There are no randomized trials of allogeneic HCT. In the present study, updated individual patient data were collected and analyzed from studies with information on availability of matched sibling donor (used to mimic randomization) and from randomized trials of autograft versus chemotherapy. Data from 13 studies including 2962 patients, excluding Philadelphia chromosome-positive patients, showed a survival benefit for having a matched sibling donor for patients < 35 years of age (OR = 0.79; 95% CI, 0.70-0.90, P = .0003) but not for those ≥ 35 years of age (OR = 1.01; 95% CI, 0.85-1.19, P = .9; heterogeneity P = .03) because of the higher absolute risk of nonrelapse mortality for older patients. No differences were seen by risk group. There was a trend toward inferior survival for autograft versus chemotherapy (OR = 1.18; 95% CI, 0.99-1.41; P = .06). No beneficial effect of autografting was seen compared with chemotherapy in this analysis. We conclude that matched sibling donor myeloablative HCT improves survival only for younger patients, with an absolute benefit of approximately 10% at 5 years. Improved chemotherapy outcomes and reduced nonrelapse mortality associated with allogeneic HCT may change the relative effects of these treatments in the future.