High-risk B-lineage Acute Lymphoblastic Leukemia Research Articles

VpreB surrogate light chain expression in B-lineage ALL: a report from the Children's Oncology Group

AbstractImmunotherapies directed against B-cell surface markers have been a common developmental strategy to treat B-cell malignancies. The immunoglobulin heavy chain surrogate light chain (SLC), comprising the VpreB1 (CD179a) and Lamda5 (CD179b) subunits, is expressed on pro- and pre-B cells, where it governs pre–B-cell receptor (BCR)-mediated autonomous survival signaling. We hypothesized that the pre-BCR might merit the development of targeted immunotherapies to decouple “autonomous” signaling in B-lineage acute lymphoblastic leukemia (B-ALL). We used the Children's Oncology Group (COG) minimal residual disease (MRD) flow panel to assess pre-BCR expression in 36 primary patient samples accrued to COG standard- and high-risk B-ALL studies through AALL03B1. We also assessed CD179a expression in 16 cases with day 29 end-induction samples, preselected to have ≥1% MRD. All analyses were performed on a 6-color Becton-Dickinson flow cytometer in a Clinical Laboratory Improvement Amendment/College of American Pathologist–certified laboratory. Among 36 cases tested, 32 cases were at the pre-B and 4 cases were at the pro-B stages of developmental arrest. One or both monoclonal antibodies (mAbs) showed that CD179a was present in ≥20% of the B-lymphoblast population. All cases expressed CD179a in the end-induction B-lymphoblast population. The CD179a component of the SLC is commonly expressed in B-ALL, regardless of genotype, stage of developmental arrest, or National Cancer Institute risk status.

Blinatumomab Is Well Tolerated Maintenance Therapy Following Allogeneic Hematopoietic Cell Transplantation for Acute Lymphoblastic Leukemia

<h3>Background</h3> Patients (pts) with high-risk B-lineage acute lymphoblastic leukemia (ALL) have a high rate of relapse, even after allogeneic hematopoietic cell transplantation (HCT). In an effort to reduce the risk for relapse, we investigated the role of blinatumomab (Blin), a bi-specific T cell immunotherapy targeting CD19, as maintenance therapy following allogeneic HCT. We rationalized that this is an ideal agent with little cytotoxicity, and the potential to provide immune protection against disease relapse during the first year post HCT when GVL is still maturing. <h3>Methods</h3> Adult pts with B-ALL deemed high risk for relapse defined as disease stage beyond CR1, active disease including MRD, or presence of high risk molecular mutations or karyotype at time of HCT, or patients with evidence of MRD post HCT, were eligible for study enrollment; prior Blin treatment was allowed. Pts with active disease or GVHD requiring steroid therapy post HCT were excluded. Pts were scheduled to receive 4 cycles of Blin at 28 μg/24 hours over 4 weeks, with the first cycle to be administered within the first 3 months post HCT after count recovery; subsequent cycles at 6, 9, 12 months following HCT. <h3>Results</h3> 12 pts with median age 30 years (range, 21-65 years) were treated to date with characteristics and outcomes reported in Table 1. The median days to start of therapy post HCT was 84 (range, 38-105 days). There was no reported CRS, GVHD, graft failure, or grade 5 adverse events (AE). A cumulative 26 cycles of Blin were administered with 7 Blin-related grade 3 or 4 AEs reported (leukopenia n=4, transaminitis n=2, rash n=1). Grade 2 neurotoxicity was noted in 1 pt. Median follow up was 8.5 months post HCT (range 2-35 months). None of the 8 pts who were MRD negative post HCT have relapsed. We performed multiparametric flow cytometry studies on serial peripheral blood patient samples collected prospectively at multiple time points to measure T cell subsets, T-cell function and cell surface expression of various checkpoint inhibitors including PD1, TIGIT, Tim3, 2B4 and CD160. Samples were studied on an X-20 Fortessa, and the data analyzed using Kaluza software. The 4 pts who progressed on Blin maintenance had lower CD8 to CD4 ratio compared to non-progressors (45.75:42.01 vs 16.53:59.72) (Figure 1). Furthermore, compared to healthy controls, we observed higher levels of checkpoint molecules as multiple checkpoints per cell. PD1 and TIGIT upregulation and co-expression were more common in progressing patients compared to non-progressors (Figure 2). <h3>Conclusion</h3> We observed that Blin maintenance following allogeneic HCT for B-ALL is well tolerated, and encouraging for pts who are MRD negative post HCT. More pts need to be treated to confirm the efficacy of this approach.Strategies to increase CD8 levels and blockade against checkpoint inhibitors may overcome resistance to therapy.

Prognostic impact of kinase-activating fusions and IKZF1 deletions in pediatric high-risk B-lineage acute lymphoblastic leukemia

AbstractRecurrent chromosomal rearrangements carry prognostic significance in pediatric B-lineage acute lymphoblastic leukemia (B-ALL). Recent genome-wide analyses identified a high-risk B-ALL subtype characterized by a diverse spectrum of genetic alterations activating kinases and cytokine receptor genes. This subtype is associated with a poor prognosis when treated with conventional chemotherapy but has demonstrated sensitivity to the relevant tyrosine kinase inhibitors. We sought to determine the frequency of kinase-activating fusions among National Cancer Institute (NCI) high-risk, Ph-negative, B-ALL patients enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 05-001 and to describe their associated clinical characteristics and outcomes. Among the 105 patients screened, 16 (15%) harbored an ABL-class fusion (ETV6-ABL1: n = 1; FOXP1-ABL1: n = 1; SFPQ-ABL1: n = 1; ZC3HAV1-ABL2: n = 1) or a fusion activating the JAK-STAT pathway (P2RY8-CRLF2: n = 8; PAX5-JAK2: n = 4). Sixty-nine percent of patients with an identified fusion had a concomitant IKZF1 deletion (n = 11). In univariate analysis, fusion-positivity and IKZF1 deletion were each associated with inferior event-free survival; IKZF1 deletion retained statistical significance in multivariable analysis (hazard ratio, 2.64; P = .019). Our findings support therapy intensification for IKZF1-altered patients, irrespective of the presence of a kinase-activating fusion.

Neurocognitive Functioning of Children Treated for High-Risk B-Acute Lymphoblastic Leukemia Randomly Assigned to Different Methotrexate and Corticosteroid Treatment Strategies: A Report From the Children's Oncology Group.

Purpose Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for neurocognitive deficits that are associated with treatment, individual, and environmental factors. This study examined the impact of different methotrexate (MTX) and corticosteroid treatment strategies on neurocognitive functioning in children with high-risk B-lineage ALL. Methods Participants were randomly assigned to receive high-dose MTX with leucovorin rescue or escalating dose MTX with PEG asparaginase without leucovorin rescue. Patients were also randomly assigned to corticosteroid therapy that included either dexamethasone or prednisone. A neurocognitive evaluation of intellectual functioning (IQ), working memory, and processing speed (PS) was conducted 8 to 24 months after treatment completion (n = 192). Results The method of MTX delivery and corticosteroid assignment were unrelated to differences in neurocognitive outcomes after controlling for ethnicity, race, age, gender, insurance status, and time off treatment; however, survivors who were age < 10 years at diagnosis (n = 89) had significantly lower estimated IQ ( P < .001) and PS scores ( P = .02) compared with participants age ≥ 10 years. In addition, participants who were covered by US public health insurance had estimated IQs that were significantly lower ( P < .001) than those with US private or military insurance. Conclusion Children with high-risk B-lineage ALL who were age < 10 years at diagnosis are at risk for deficits in IQ and PS in the absence of cranial radiation, regardless of MTX delivery or corticosteroid type. These data may serve as a basis for developing screening protocols to identify children who are at high risk for deficits so that early intervention can be initiated to mitigate the impact of therapy on neurocognitive outcomes.

Molecular profiling of gene copy number abnormalities in key regulatory genes in high-risk B-lineage acute lymphoblastic leukemia: frequency and their association with clinicopathological findings in Indian patients.

Genes related to key cellular pathways are frequently altered in B cell ALL and are associated with poor survival especially in high-risk (HR) subgroups. We examined gene copy number abnormalities (CNA) in 101 Indian HR B cell ALL patients and their correlation with clinicopathological features by multiplex ligation-dependent probe amplification. Overall, CNA were detected in 59 (59%) cases, with 26, 10 and 23% of cases harboring 1, 2 or +3 CNA. CNA were more prevalent in BCR-ABL1 (60%), pediatric (64%) and high WCC (WBC count) (63%) patients. Frequent genes deletions included CDNK2A/B (26%), IKZF1 (25%), PAX5 (14%), JAK2 (7%), BTG1 (6%), RB1 (5%), EBF1 (4%), ETV6 (4%), while PAR1 region genes were predominantly duplicated (20%). EBF1 deletions selectively associated with adults, IKZF1 deletions occurred frequently in high WCC and BCR-ABL1 cases, while PAR1 region gains significantly associated with MLL-AF4 cases. IKZF1 haploinsufficiency group was predominant, especially in adults (65%), high WCC (60%) patients and BCR-ABL1-negative (78%) patients. Most cases harbored multiple concurrent CNA, with IKZF1 concomitantly occurring with CDNK2A/B, PAX5 and BTG1, while JAK2 occurred with CDNK2A/B and PAX5. Mutually exclusive CNA included ETV6 and IKZF1/RB1, and EBF1 and JAK2. Our results corroborate with global reports, aggregating molecular markers in Indian HR B-ALL cases. Integration of CNA data from rapid methods like MLPA, onto background of existing gold-standard methods detecting significant chromosomal abnormalities, provides a comprehensive genetic profile in B-ALL.

Kinase-Activating Fusions in Pediatric High-Risk B-Lineage Acute Lymphoblastic Leukemia (ALL): a Report from the Dana-Farber Cancer Institute (DFCI) ALL Consortium

Abstract Background. Recurrent chromosomal rearrangements carry prognostic significance in pediatric B-lineage acute lymphoblastic leukemia (B-ALL). Recent genome-wide analyses identified a diverse spectrum of chromosomal rearrangements resulting in novel chimeric fusions associated with poor prognosis when treated with conventional chemotherapy. These fusions are observed more frequently in NCI High-Risk (HR) B-ALL compared with NCI Standard Risk (SR) patients. They often activate ABL and JAK-STAT signaling pathways and have demonstrated sensitivity to the relevant tyrosine kinase inhibitors (TKIs) in in vitro assays and ex vivomodels. The objective of this study was to determine the frequency of NCI HR B-ALL patients enrolled on DFCI ALL Consortium Protocol 05-001 with a kinase-activating fusion that would be amenable to TKI therapy and to describe their associated clinical characteristics and outcomes. Methods. Between 2005-2011, 219 NCI HR, Philadelphia chromosome (Ph)-negative, B-ALL patients were enrolled on DFCI ALL Consortium Protocol 05-001, 105 of whom had sufficient material to undergo kinase fusion testing by validated multiplex reverse transcription polymerase chain reaction (RT-PCR) assays. A total of 35 kinase fusions of ABL-class (ABL1, ABL2, PDGFRB, CSF1R), JAK2 and CRLF2 rearrangements were examined. IGH@-CRLF2 and EPOR rearrangements were not assessed. Fusion products were predicted by NCBI BLAST algorithms, confirmed by singleplex PCR and Sanger sequencing and aligned using CLC Main Workbench Version 7.6.1. IKZF1 deletion (del) status had previously been assessed by multiplex ligation-dependent probe amplification (MLPA). Fisher's exact test and the Wilcoxon rank sum test were used to compare patient characteristics to those with and without any identified fusion for categorical and continuous variables respectively. Event-free survival (EFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared using a log rank test. Univariate and multivariable Cox proportional hazards models of EFS were constructed. Results. Among 105 NCI HR, Ph-negative, B-ALL patients, 16 (15%) were found to harbor an ABL-class fusion (ETV6-ABL1: n=1; FOXP1-ABL1: n=1; SFPQ-ABL1: n=1; ZC3HAV1-ABL2: n=1) or a fusion activating the JAK-STAT pathway (P2RY8-CRLF2: n=8; PAX5-JAK2: n=4). Sixty-nine percent of patients with an identified fusion (Fusion +) had a concomitant IKZF1 del (n=11). Features associated with fusion-positivity were age of 10 years or older (p=0.003), male sex (p=0.03), Hispanic ethnicity (p=0.01) and IKZF1 del (p=0.0005) (Table 1). Fifty percent of Fusion+ patients experienced an event (induction death (n=1); induction failure (n=1); or relapse (n=6)) compared to 24% of patients without a fusion. The 5-year EFS and OS were 48% (95% CI 22-70%) and 68% (95% CI 39-85%) for Fusion+ patients compared to 78% (95% CI 67-85%) and 88% (95% CI 79-93%) for those without fusions (Figure 1). In univariate analysis, fusion-positivity (HR: 2.66, p=0.02) and IKZF1 del (HR: 3.21; p=0.0018) were each significantly associated with inferior EFS, while age and presenting leukocyte count were not. In multivariable analysis, IKZF1 del, but not fusion-positivity, retained statistical significance (HR: 2.64, p=0.02). Conclusion. Fifteen percent of NCI HR, Ph-negative, B-ALL patients enrolled on DFCI ALL Consortium 05-001 were found to have a kinase-activating fusion. Fusion+ patients frequently harbored concomitant IKZF1 deletion and had an inferior outcome. Future studies should focus on developing clinical strategies to rapidly identify these patients at diagnosis and to test whether the addition of the relevant TKIs to their treatment will improve their outcome. Disclosures Asselin: Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Sigma Tau Pharamceuticals: Consultancy. Loh:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding.

Glutamate Receptor Polymorphisms Contribute to Glucocorticoid-Associated Osteonecrosis

BackgroundGlucocorticoids are an essential component of current treatment regimens for childhood acute lymphoblastic leukemia (ALL), and are a component of treatment for many autoimmune and inflammatory conditions. A common therapy-related and dose-limiting toxicity in ALL is glucocorticoid-induced osteonecrosis (ON). The mechanism and underlying genetic basis of ON risk are likely multifactorial.MethodsWe performed the largest genome-wide association study (GWAS) of ON to date in 2285 children with ALL who were treated on the Children’s Oncology Group (COG) AALL0232 frontline protocol for high risk B-lineage ALL. We also studied two validation cohorts: 361 children with ALL treated on the frontline St. Jude Total XV protocol for ALL, and 309 children and adults treated with corticosteroids for oncologic and non-oncologic indications in the Vanderbilt University Medical Center BioVU DNA repository. Single nucleotide polymorphism (SNP) genotyping was performed using Illumina and Affymetrix Human Gene Chip Arrays. Additional SNPs were imputed using 1000 Genomes as the reference genome with MaCH-Admix and IMPUTE2. Testing for association was performed by Cox proportional hazard and logistic regression, with meta-analysis across cohorts using Stouffer’s Z-score method. Gene based and pathway analyses were performed using SNP-set Kernel Association Test (SKAT) and Ingenuity Pathway Analysis (IPA), respectively.ResultsIn the discovery GWAS for AALL0232, adjusting for gender, age, ancestry and treatment, the SNP with the strongest association was at 9q31.1 (rs28584318, odds ratio [OR] = 2.00, P = 4.86 x 10-7), near the GRIN3A locus (glutamate [NMDA] receptor subunit 3A). The same SNP was validated in both the St. Jude and Vanderbilt cohorts after adjusting for covariates (OR = 1.81 and 2.26, P = 0.0734 and 0.0073 respectively). Overall, patients with the variant genotype at rs28584318 in 9q31.1 had a higher incidence of ON compared with those patients who did not: AALL0232, St. Jude Total XV and Vanderbilt BioVU (15.8% vs 9.7%, 21.8% vs. 20.4%, 35.6% vs 24.0%). In the meta-analysis with both discovery and validation cohorts combined, the SNP at 9q31.1 (P = 5.34 x 10-8), and an additional variant in GRIK1 (glutamate receptor, ionotropic, kainate, rs2154490 P = 7.24 x 10-7) were most associated with risk of ON. Pathway analysis of the genes implicated in the discovery and validation cohorts also identified the glutamate pathway as the top overlapping canonical pathway present in all three cohorts (COG AALL0232 P = 0.045; St. Jude Total XV P = 0.011; Vanderbilt P = 0.037).ConclusionsThese findings demonstrate an association between loci in the glutamate pathway and glucocorticoid-induced ON. The glutamate pathway could be linked to ON via several mechanisms, including that glutamate receptors are involved in the mechanical signaling of bone and regulation of osteoblasts and osteoclastogenesis, and are affected by glucocorticoids. That this pathway was also implicated in a non-ALL cohort suggests glutamate pathway variation may modulate risk for ON across a wide array of patients treated with glucocorticoids. [Display omitted] DisclosuresHunger:Sigma Tau Pharmaceuticals: Honoraria; Jazz Pharmaceuticals: Honoraria. Evans:St. Jude: In accordance with institutional policy (St. Jude), I and/or my spouse have in the past received a portion of the income St. Jude receives from licensing patent rights related to TPMT polymorphisms as clinical diagnostics. Patents & Royalties.

Minimal Residual Disease Detection Using High-Throughput Sequencing Predicts Clinical Outcome in Patients with Pediatric B-Lineage Acute Lymphoblastic Leukemia

Background: Minimal residual disease (MRD) assessment at the end of induction is critical for risk stratification of B-lineage acute lymphoblastic leukemia (B-ALL) patients. There are multiple techniques for molecular MRD assessment, including next-generation sequencing (NGS) and allele-specific oligonucleotide PCR (ASO-PCR) amplification of immunoglobulin (Ig) or T-cell receptor rearrangements. Leukemia-specific rearrangements can be identified in >97% of B-ALL patients using the NGS-based LymphoSIGHT™ method, while ASO-PCR can typically identify leukemia-specific rearrangements in only 80-90% of B-ALL patients. In this report, we assessed the ability of the NGS method to predict event-free survival (EFS) in a cohort of B-ALL patients who were inevaluable by ASO-PCR.Methods: All patients were treated between 2005-2011 on a clinical trial conducted by the Dana-Farber Cancer Institute (DFCI) ALL Consortium (05-001) on which high levels of end-induction MRD (≥10-3) led to intensified treatment. The 37 pediatric B-ALL patients included in this study were inevaluable by ASO-PCR, and therefore this cohort represents a subset of patients in whom a decision to intensify therapy per protocol could not be made. Archived DNA samples from diagnosis and Day 32 were provided for MRD assessment using the NGS method. Using universal primer sets, we amplified the immunoglobulin (IGH-VDJ, IGH-DJ and IGK) and T cell receptor (TRB, TRD, TRG) loci in diagnostic bone marrow samples. Leukemia-specific clonotypes were identified in the diagnostic sample of each patient based on high-frequency within the B-cell and/or T-cell repertoire. The presence of leukemia-specific clonotypes was then assessed in the end-induction (Day 32) sample. NGS MRD assessment was performed blinded to all clinical and ASO-PCR information on these patients. The association of NGS MRD results and clinical outcome (EFS) was examined, and significance assessed using the log-rank test.Results: Of 37 patients who were inevaluable for end-induction MRD by ASO-PCR, leukemia-specific clonotypes were successfully identified in 35 (95%) by the NGS method. The use of a threshold of 10-3, which is the ASO-PCR threshold used for risk-stratification on DFCI protocols, demonstrated significantly improved EFS between the MRD negative and MRD positive groups (p<0.0001) (Figure 1A). A similar analysis with a threshold of 10-4 also demonstrated significantly improved EFS between the MRD negative and MRD positive groups (p<0.0001) (Figure 1B).Conclusions: This study demonstrates the prognostic significance of NGS-based MRD assessment in pediatric patients with B-ALL. This NGS-based assay led to successful assessment of MRD in 95% of patients who were inevaluable by ASO-PCR. The NGS method represents an alternative approach for clinical MRD monitoring that could fundamentally improve the ability to identify high-risk B-ALL patients and potentially improve their outcome. [Display omitted] [Display omitted] DisclosuresZheng:Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.

Rational design of an immunoconjugate for selective knock-down of leukemia-specific E2A–PBX1 fusion gene expression in human Pre-B leukemia

The t(1;19)(q23;p13) is one of the most common chromosomal translocations in acute lymphoblastic leukemia (ALL) and results in production of the transforming oncoprotein E2A-PBX1. Here we first report a novel, biomarker-guided biotherapy strategy for personalized treatment of t(1;19)(+) ALL. A supervised interrogation of the gene expression profiles of primary leukemic cells from a cohort of 207 children with high risk B-lineage ALL identified up-regulated CD19 gene expression as a biomarker for t(1;19)(+) ALL. A disulfide-linked immunoconjugate of a 5-amino-modified 24 mer phosphorothioate anti-sense E2A-PBX1 oligonucleotide (AON) with a mAb specific for a CD19 receptor (αCD19-AON) was prepared as a CD19-directed and leukemia-specific biotherapeutic agent against E2A-PBX1(+) B-lineage ALL. Treatment of E2A-PBX1(+) leukemia cells with low nanomolar concentrations of αCD19-AON resulted in selective depletion of E2A-PBX1 transcripts and caused apoptotic destruction and abrogation of clonogenic growth. Subcutaneously administered αCD19-AON at a total dose level of 93 nmol kg(-1) delivered over 14 days using a micro-osmotic pump more than doubled the leukemia-free survival time of SCID mice in a xenograft model of E2A-PBX1(+) human B-lineage ALL (82.0 ± 1.9 days vs. 37.0 ± 0.1 days, P < 0.0001). Both the AON moiety and the targeting CD19-specific mAb moiety were required for the in vitro as well as in vivo anti-leukemic activity of αCD19-AON. The observed in vitro and in vivo anti-leukemic potency of the αCD19-AON immunoconjugate provides the first preclinical proof-of-principle that t(1;19)(+) high risk B-lineage ALL can be treated with leukemia-specific biotherapeutic agents that knock-down E2A-PBX1 expression.

Augmentation of the Antileukemia Potency of Total-Body Irradiation (TBI) by a Novel P-site Inhibitor of Spleen Tyrosine Kinase (SYK)

A novel spleen tyrosine kinase (SYK) P-site inhibitor, 1,4-Bis (9-O dihydroquinidinyl) phthalazine/hydroquinidine 1,4-phathalazinediyl diether (C-61), (but not vehicle) markedly enhanced H(2)O(2)-induced apoptosis of primary leukemia cells from each of five relapsed B-lineage acute lymphoblastic leukemia (ALL) patients, as measured by in vitro TUNEL assays. A highly radiation-resistant subclone of the murine B-lineage leukemia cell line BCL-1 was next used to investigate the in vivo radiosensitizing effects of C-61. C-61 enhanced the antileukemia potency of 7 Gy total-body irradiation (TBI) in the context of syngeneic bone marrow transplantation (BMT) at 20% of its nonobservable adverse effect level (NOAEL) that does not exhibit detectable single-agent activity against BCL-1 leukemia in vivo. Based on this preclinical proof-of-principle study, we hypothesize that the incorporation of C-61 into the pretransplant TBI regimens of patients with recurrent or high-risk B-lineage acute lymphoblastic leukemia (ALL) will help overcome the radiochemotherapy resistance of their leukemia cells and thereby improve their treatment response and survival outcome after BMT.

Long-term results of Taiwan Pediatric Oncology Group studies 1997 and 2002 for childhood acute lymphoblastic leukemia

The long-term outcome of 1390 children with acute lymphoblastic leukemia (ALL), treated in two successive clinical trials (Taiwan Pediatric Oncology Group (TPOG)-ALL-97 and TPOG-ALL-2002) between 1997 and 2007, is reported. The event-free survival improved significantly (P=0.0004) over this period, 69.3+/-1.9% in 1997-2001 to 77.4+/-1.7% in 2002-2007. A randomized trial in TPOG-97 testing L-asparaginase versus epidoxorubicin in combination with vincristine and prednisolone for remission induction in standard-risk (SR; low-risk) patients yielded similar outcomes. Another randomized trial, in TPOG-2002, showed that for SR patients, two reinduction courses did not improve long-term outcome over one course. Decreasing use of prophylactic cranial irradiation in the period 1997-2008 was not associated with increased rates of CNS relapse, prompting complete omission of prophylactic cranial irradiation from TPOG protocols, beginning in 2009. Decreased use of etoposide and cranial irradiation likely contributed to the low incidence of second cancers. High-risk B-lineage ALL, T-cell, CD10 negativity, t(9;22), infant, and higher leukocyte count were consistently adverse factors, whereas hyperdiploidy >50 was a consistently favorable factor. Higher leukocyte count and t(9;22) retained prognostic significance in both TPOG-97 and TPOG-2002 by multivariate analysis. Although long-term outcome in TPOG clinical trials is comparable with results being reported worldwide, the persistent strength of certain prognostic variables and the lower frequencies of favorable outcome predictors, such as ETV6-RUNX1 and hyperdiploidy >50, in Taiwanese children warrant renewed effort to cure a higher proportion of patients while preserving their quality of life.

Cord Blood-Derived T Cells Can Be Genetically Engineered to Be B-Lineage All-Specific: Towards Adoptive Immunotherapy after Umbilical Cord Blood Transplantation.

Relapse of B-lineage (CD19+) acute lymphoblastic leukemia (ALL) remains a major impediment to the therapeutic success of allogeneic umbilical cord blood transplant (UCBT). The adoptive transfer of donor-derived tumor-specific T-cells is a conceptually attractive means to improve the graft-versus-leukemia-effect at the time of minimal residual disease to improve relapse-rates without exacerbating graft-versus-host-disease. However, adoptive immunotherapy after banked UCBT has been limited by the functional naïveté of neonatal T cells and difficulty obtaining T cells from the unrelated donor. These hurdles can now be overcome by genetically rendering cord blood-derived T cells to be specific for CD19 and expanding the T cells ex vivo from small numbers of cord blood cells, in compliance with current good manufacturing practices for phase I/II trials. To generate T cells that target CD19+ malignant cells, we have used non-viral gene transfer to introduce a DNA plasmid to express a CD19-specific chimeric immunoreceptor, designated CD19R, which binds to cell-surface CD19 via an scFv, independent of MHC, and triggers T-cell activation through CD3- ζ. To safeguard the safety of recipients of adoptive immunotherapy, the DNA plasmid co-expresses the bi-functional hygromycin phosphotransferase/HSV-1 thymidine kinase (HyTK) selection/suicide gene. To assess in vivo the fate of adoptively transferred T cells in mice; a novel tri-functional gene linking firefly luciferase (ffLuc) with HyTK (ffLucHyTK) was generated. The process ex vivo to expand cord blood-derived T cells, which is currently employed at COH in human trials, uses reiterative 14-day additions of OKT3, rhIL-2, cytocidal concentrations of hygromycin, and irradiated peripheral blood mononuclear cells (PBMC) and LCL as feeder cells. The expanded genetically manipulated cord-blood derived T cells express cell-surface markers of differentiated effector cells, similar to the phenotype of CD19-specific T cells derived from PBMC. In vitro the CD19R+HyTK+ cord blood-derived T cells are activated for cytolysis and cytokine production by CD19+ tumor cells. In vivo these genetically modified T cells can be used to eradicate established CD19+ tumors and undergo ganciclovir-mediated ablation, as demonstrated by non-invasive serial imaging of luciferase-mediated bioluminescence (see Figure). These data support a clinical trial to test the safety and feasibility of adoptive transfer of CD19-specific umbilical cord-blood derived T-cells for patients with high risk B-lineage ALL undergoing UCBT.Legend: Non-invasive in vivo biophotonic imaging demonstrates that (A) CD19+ tumor expressing ffLuc gene are eliminated by CD19R+HyTK+ cord-blood derived T cells, and (B) CD19R+ffLuc+HyTK+ cord-blood derived T cells are ablated by ganciclovir. Top row: prior to adoptive immunotherapy or ganciclovir treatment. Bottom row: after adoptive immunotherapy or ganciclovir treatment. Two representative mice are shown. [Display omitted]

Autologous Peripheral Blood Stem Cell Transplantation for Adults with B-Lineage Acute Lymphoblastic Leukemia: A Pilot Study

We conducted a pilot study on autologous peripheral blood stem cell transplantation (PBSCT) for 11 adults with B-lineage acute lymphoblastic leukemia (ALL) in first complete remission (CR) or even in those with more advanced stages. All patients achieved CR by induction therapy, of whom 10 were treated with anthracycline, vincristine and prednisolone-based regimens. After consolidation therapy, all patients except one received high-dose cytarabine followed by granulocyte colony-stimulating factor (G-CSF) administration to collect PBSCs. Ten patients received busulfan 4 mg/kg for 4 days, etoposide 20 mg/kg for 3 days and ran-imustine 200 mg/m2 for 2 days as a conditioning regimen. One received a regimen consisting of etoposide, cyclophosphamide and total body irradiation. From day I, G-CSF was given intravenously, and no additional chemotherapy was administered. At the median follow-up time of 30.8 months, four of six patients with standard-risk B-lineage ALL survived within the range of 19.7 to 85.4 months without relapse. In contrast, only one of five with high-risk B-lineage ALL survived for 36.3 months without relapse. Autologous PBSCT as post-remission therapy may prolong CR in adults with standard-risk B-lineage ALL.

Prognostic Significance of T-Lineage Leukemic Cell Growth in SCID Mice: A Children's Cancer Group Study

Contemporary intensive therapies are effective for the majority of pediatric T-lineage acute lymphoblastic leukemia (ALL) patients, thus current challenge is to identify patients who may benefit from alternative treatment modalities. Previously, we demonstrated that human leukemic cell growth in the severe combined immunodeficiency (SCID) mouse was a significant prognostic factor for very high risk B-lineage ALL patients. In the current report we show that primary leukemic cells from 24 of 88 (27%) T-lineage ALL patients (SCID+) caused histopathologically detectable leukemia in SCID mice. These SCID+ patients were similar to SCID- (n = 64) patients with respect to virtually all presenting features, including age, sex, race, and leukocyte count. Growth of primary leukemic cells in SCID mice was not a significant predictor of outcome for the aggregate population of T-lineage ALL patients. Two-year event-free survival (EFS) outcomes for SCID+ patient and SCID- patients were 76.2% (SD = 5.6%) and a 64.0% (SD = 10.4%; p = 0.20). Overall survival also was similar between the two groups (p = 0.36). Among the subset of patients with M1 or M2 marrow status by day 7 of induction chemotherapy (rapid early responders), those who were SCID+ had poorer outcomes than those who were SCID”, with a 2-year EFS of 68.4% (SD = 11.9%) vs. 85.7% (SD = 6.0%) and relative hazard rate of 3.06 (p = 0.06). These data suggest that leukemic cell growth in SCID mice may identify a subset of T-lineage ALL patients who are at higher risk for relapse despite achieving a rapid early response to induction chemotherapy.

Leukemic Cell Growth in SCID Mice as a Predictor of Relapse in High-Risk B-Lineage Acute Lymphoblastic Leukemia

Mice with severe combined immunodeficiency (SCID) provide a model system to examine the in vivo homing, engraftment, and growth patterns of normal and malignant human hematopoietic cells. The relation between leukemic cell growth in this model and the treatment outcome in patients from whom cells were derived has not been established. Leukemic cells from 42 children with newly diagnosed high-risk B-lineage acute lymphoblastic leukemia were inoculated intravenously into CB.17 SCID mice. Mice were killed at 12 weeks or when they became moribund as a result of disseminated leukemia. All mice were necropsied and subjected to a series of laboratory studies to assess their burden of human leukemic cells. Twenty-three patients whose leukemic cells caused histopathologically detectable leukemia in SCID mice had a significantly higher relapse rate than the 19 patients whose leukemic cells did not (estimated 5-year event-free survival: 29.5% v 94.7%; 95% confidence intervals, 11.2% to 50.7% v 68.1% to 99.2%; P < .0001 by log-rank test). The occurrence of overt leukemia in SCID mice was was a highly significant predictor of patient relapse. The estimated instantaneous risk of relapse for patients whose leukemic cells caused overt leukemia in SCID mice was 21.5-fold greater than that for the remaining patients. Thus, growth of human leukemic cells in SCID mice is a strong and independent predictor of relapse in patients with newly diagnosed high-risk B-lineage acute lymphoblastic leukemia.

Autologous Bone Marrow Transplantation in High-Risk Remission B-Lineage Acute Lymphoblastic Leukemia Using a Cocktail of Three Monoclonal Antibodies (BA-1/CD24, BA-2/CD9, and BA-3/CD10) Plus Complement and 4-Hydroperoxycyclophosphamide for Ex Vivo Bone Marrow Purging

Fourteen patients with high-risk B-lineage acute lymphoblastic leukemia (ALL) in complete remission underwent autologous bone marrow transplantation (BMT) using a combined immunochemopurging protocol. A monoclonal antibody (MoAb) cocktail of BA-1, BA-2, and BA-3 plus rabbit complement (C') plus 4-hydroperoxycyclophosphamide (4-HC) was used to eliminate residual occult leukemia cells from autografts. All patients were conditioned with single-dose total body irradiation (TBI) followed by high-dose Ara-C. All 14 patients engrafted at a median of 24 days (range, 12 to 36 days). Three patients are alive and disease free at 3.5 years, 3.9 years, and 4.1 years post-BMT. The Kaplan-Meiser estimate and standard error of the probability of sustained remission was 23% +/- 12% at 3.5 years post-BMT with a mean relapse-free interval of 1.4 +/- 0.4 years. The disease-free survival (DFS) at 3.5 years was 21% +/- 11%, with a mean DFS time of 1.3 +/- 0.4 years. A novel and quantitative minimal residual disease (MRD) detection assay, which combines fluorescence-activated multiparameter flow cytometry and cell sorting with leukemic progenitor cell (LPC) colony assays, was used to analyze remission BM samples from B-lineage ALL patients for residual LPC, and to evaluate the efficacy of ex vivo BM purging. Notably, the minimal residual leukemia burden before BMT, as measured by the percentage of B-lineage LPC in the pre-BMT remission BM samples, indicated the outcome of the BMT. The median value for the minimal residual leukemia burden before BMT was 0.0035% (35 LPC/10(6) mononuclear cells). The Kaplan-Meier estimates and standard errors of the probability of remaining in remission after BMT were 43% +/- 19% for patients whose BM samples contained less than or equal to 0.0035% LPC and 0% +/- 0% for patients whose BM samples contained greater than 0.0035% B-lineage LPC (P less than .05). In contrast to the minimal residual leukemia burden measured by the described MRD assay system, the percentage of blasts or TdT+ cells in the remission BM samples did not correlate with the probability of relapse. The applied purging protocol showed variable success in destroying target B-lineage LPC populations contaminating the autografts. While in some cases purging was highly effective, eliminating up to greater than or equal to 4 logs of residual B-lineage LPC, in other cases only 0.1 to 0.2 logs of B-lineage LPC were purged.(ABSTRACT TRUNCATED AT 400 WORDS)

Autologous bone marrow transplantation in high-risk remission B-lineage acute lymphoblastic leukemia using a cocktail of three monoclonal antibodies (BA-1/CD24, BA-2/CD9, and BA-3/CD10) plus complement and 4- hydroperoxycyclophosphamide for ex vivo bone marrow purging

Fourteen patients with high-risk B-lineage acute lymphoblastic leukemia (ALL) in complete remission underwent autologous bone marrow transplantation (BMT) using a combined immunochemopurging protocol. A monoclonal antibody (MoAb) cocktail of BA-1, BA-2, and BA-3 plus rabbit complement (C′) plus 4-hydroperoxycyclophosphamide (4-HC) was used to eliminate residual occult leukemia cells from autografts. All patients were conditioned with single-dose total body irradiation (TBI) followed by high-dose Ara-C. All 14 patients engrafted at a median of 24 days (range, 12 to 36 days). Three patients are alive and disease free at 3.5 years, 3.9 years, and 4.1 years post-BMT. The Kaplan-Meiser estimate and standard error of the probability of sustained remission was 23% +/- 12% at 3.5 years post-BMT with a mean relapse-free interval of 1.4 +/- 0.4 years. The disease-free survival (DFS) at 3.5 years was 21% +/- 11%, with a mean DFS time of 1.3 +/- 0.4 years. A novel and quantitative minimal residual disease (MRD) detection assay, which combines fluorescence-activated multiparameter flow cytometry and cell sorting with leukemic progenitor cell (LPC) colony assays, was used to analyze remission BM samples from B-lineage ALL patients for residual LPC, and to evaluate the efficacy of ex vivo BM purging. Notably, the minimal residual leukemia burden before BMT, as measured by the percentage of B-lineage LPC in the pre-BMT remission BM samples, indicated the outcome of the BMT. The median value for the minimal residual leukemia burden before BMT was 0.0035% (35 LPC/10(6) mononuclear cells). The Kaplan-Meier estimates and standard errors of the probability of remaining in remission after BMT were 43% +/- 19% for patients whose BM samples contained less than or equal to 0.0035% LPC and 0% +/- 0% for patients whose BM samples contained greater than 0.0035% B-lineage LPC (P less than .05). In contrast to the minimal residual leukemia burden measured by the described MRD assay system, the percentage of blasts or TdT+ cells in the remission BM samples did not correlate with the probability of relapse. The applied purging protocol showed variable success in destroying target B-lineage LPC populations contaminating the autografts. While in some cases purging was highly effective, eliminating up to greater than or equal to 4 logs of residual B-lineage LPC, in other cases only 0.1 to 0.2 logs of B- lineage LPC were purged.(ABSTRACT TRUNCATED AT 400 WORDS).