Outcomes after induction failure in childhood acute lymphoblastic leukemia

Risk assessment of relapse by lineage-specific monitoring of chimerism in children undergoing allogeneic stem cell transplantation for acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation is required as rescue therapy in about 20% of pediatric patients with acute lymphoblastic leukemia. However, the relapse rates are considerable, and relapse confers a poor outcome. Early assessment of the risk of relapse is therefore of paramount importance for the development of appropriate measures. We used the EuroChimerism approach to investigate the potential impact of lineage-specific chimerism testing for relapse-risk analysis in 162 pediatric patients with acute lymphoblastic leukemia after allogeneic stem cell transplantation in a multicenter study based on standardized transplantation protocols. Within a median observation time of 4.5 years, relapses have occurred in 41/162 patients at a median of 0.6 years after transplantation (range, 0.13-5.7 years). Prospective screening at defined consecutive time points revealed that reappearance of recipient-derived cells within the CD34(+) and CD8(+) cell subsets display the most significant association with the occurrence of relapses with hazard ratios of 5.2 (P=0.003) and 2.8 (P=0.008), respectively. The appearance of recipient cells after a period of pure donor chimerism in the CD34(+) and CD8(+) leukocyte subsets revealed dynamics indicative of a significantly elevated risk of relapse or imminent disease recurrence. Assessment of chimerism within these lineages can therefore provide complementary information for further diagnostic and, potentially, therapeutic purposes aiming at the prevention of overt relapse. This study was registered at clinical.

TRIALS

gov with the number NC01423747.

CD38+ CD58- is an independent adverse prognostic factor in paediatric Philadelphia chromosome negative B cell acute lymphoblastic leukaemia patients

To explore new risk predictors for a high risk of relapse in Philadelphia chromosome negative (Ph-) B cell acute lymphoblastic leukaemia (B-ALL) patients, 196 paediatric Ph- B-ALL patients (≤ 18 years) were retrospectively analysed. We mainly focus on investigating the prognostic value of CD38 and CD58 expression in leukemic blasts in these patients by four colour flow cytometry. The CD38+ CD58- group (n=16) had a higher relapse rate, a shorter 3-year event-free survival (EFS) and overall survival (OS) than the CD38+ CD58+ group (n=157; 31.3% vs 10.2%, P=0.04; 52.4% vs 92.3%, P<0.01; 32.5% vs 91.0%, P=0.01); CD38+ CD58- was an independent adverse prognostic predictor for relapse (hazard ratio [HR], 0.203; 95%CI, 0.063-0.656; P=0.01), 3-year EFS (HR, 0.091; 95%CI, 0.023-0.355; P<0.01) and OS (HR, 0.102; 95%CI, 0.026-0.3971; P<0.01) in this cohort, as determined by Cox multivariate analysis. We identified, for the first time, a higher risk population of paediatric Ph- B-ALL patients with CD38+ CD58- who had a higher relapse risk and a shorter survival. Our results may allow better risk stratification and individualized treatment.

HSP90 inhibition leads to degradation of the TYK2 kinase and apoptotic cell death in T-cell acute lymphoblastic leukemia

We previously found that tyrosine kinase 2 (TYK2) signaling through its downstream effector phospho-STAT1 acts to upregulate BCL2, which in turn mediates aberrant survival of T-cell acute lymphoblastic leukemia (T-ALL) cells. Here we show that pharmacologic inhibition of heat shock protein 90 (HSP90) with a small-molecule inhibitor, NVP-AUY922 (AUY922), leads to rapid degradation of TYK2 and apoptosis in T-ALL cells. STAT1 protein levels were not affected by AUY922 treatment, but phospho-STAT1 (Tyr-701) levels rapidly became undetectable, consistent with a block in signaling downstream of TYK2. BCL2 expression was downregulated after AUY922 treatment, and although this effect was necessary for AUY922-induced apoptosis, it was not sufficient because many T-ALL cell lines were resistant to ABT-199, a specific inhibitor of BCL2. Unlike ABT-199, AUY922 also upregulated the proapoptotic proteins BIM and BAD, whose increased expression was required for AUY922-induced apoptosis. Thus, the potent cytotoxicity of AUY922 involves the synergistic combination of BCL2 downregulation coupled with upregulation of the proapoptotic proteins BIM and BAD. This two-pronged assault on the mitochondrial apoptotic machinery identifies HSP90 inhibitors as promising drugs for targeting the TYK2-mediated prosurvival signaling axis in T-ALL cells.

Refractory acute lymphoblastic leukemia in Chinese children: bridging to stem cell transplantation with clofarabine, cyclophosphamide and etoposide

Refractory or relapsed acute lymphoblastic leukemia (r/r ALL) represents the leading cause of cancer mortality in children. Clofarabine is effective in inducing remission thus enabling bridging to hematopoietic stem cell transplantation (HSCT). We report the results in treating Hong Kong Chinese pediatric patients with r/rALL by clofarabine/cyclophosphamide/etoposide (CLO-218) combination therapy. A retrospective review of patients treated between January 2009 and December 2014 in the two tertiary referral pediatric oncology units in Hong Kong. Thirteen patients were identified. All were Chinese and seven were male. Median age at clofarabine treatment was 8 years and the median duration of follow-up was 10 months. Nine patients had B-ALL and four had T-ALL. All were refractory to the preceding regimen(s). The median number of prior treatment regimens was 2; two patients had previous HSCT. Complete remission (CR) was achieved in five patients, Complete remission with incomplete counts (CRi) in two, PR in two, and non-remission (NR) in two. All four patients with T-ALL responded with three patients achieving CR. Eight out of nine patients who responded could be bridged to HSCT. Among those who were transplanted, four remained alive and in remission, three relapsed post-HSCT, and one died from transplant-related mortality. Treatment toxicities were common including febrile neutropenia in all subjects and culture-proven bacteremia in five patients. Hepatotoxicity was mild and reversible with no case of veno-occlusive disease. The clofarabine-based regimen is a promising strategy to induce disease remission in r/rALL and bridge to HSCT. Septic complications are, however, frequent necessitating prompt management with adequate supportive care in specialized centers.

Clinical features and induction outcome of childhood acute lymphoblastic leukemia in a lower/middle income population: A multi-institutional report from Pakistan

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common cancer of childhood. Some evidence suggests differences in clinical and cytogenetic characteristics of ALL based on geographic and ethnic variations. However, data on ALL characteristics and early outcome of therapy from low/middle-income countries such as Pakistan are scanty.

PROCEDURE

A prospective, multi-institutional cohort study in Karachi enrolled 646 newly diagnosed children with ALL over 3 years. Standard forms were used to collect demographic, clinical, and laboratory data at presentation and at the end of induction.

RESULTS

Of the total, 66.1% (n = 427) were males. Median age was 6 (mean ± SE 6.87 ± 0.16; range 0.16-18) years. The most common clinical presentation was fever (88.7%). BPC-ALL was diagnosed in 78.5%, while 17.5% had T-ALL; 28.8% had a WBC >50 × 10(9) /L. With 316 patients karyotyped, hypodiploidy and hyperdiploidy were seen in 5.1% and 10.7%, respectively. Of those tested, ETV6-RUNX1 translocation was detected in 13.2%, while BCR-ABL1 translocation and MLL gene rearrangements were seen in 7.3% and 4.6%, respectively. The cumulative loss to follow up before and during induction was 12.8% (n = 83) and 11.5% (n = 74) died before or during this phase. Induction was successfully completed by only 75.6% (n = 489) of the entire cohort and 69.6% (n = 450) achieved remission.

CONCLUSION

These patients had ALL with higher risk features than that reported from developed countries. One quarter failed to complete induction chemotherapy. This suboptimal result requires further study and development of innovative interventions, particularly focusing on the causes and solutions for late referral, abandonment, and infections.

Childhood Acute Lymphoblastic Leukemia: Progress Through Collaboration

PURPOSE

To review the impact of collaborative studies on advances in the biology and treatment of acute lymphoblastic leukemia (ALL) in children and adolescents.

METHODS

A review of English literature on childhood ALL focusing on collaborative studies was performed. The resulting article was reviewed and revised by the committee chairs of the major ALL study groups.

RESULTS

With long-term survival rates for ALL approaching 90% and the advent of high-resolution genome-wide analyses, several international study groups or consortia were established to conduct collaborative research to further improve outcome. As a result, treatment strategies have been improved for several subtypes of ALL, such as infant, MLL-rearranged, Philadelphia chromosome-positive, and Philadelphia chromosome-like ALL. Many recurrent genetic abnormalities that respond to tyrosine kinase inhibitors and multiple genetic determinants of drug resistance and toxicities have been identified to help develop targeted therapy. Several genetic polymorphisms have been recognized that show susceptibility to developing ALL and that help explain the racial/ethnic differences in the incidence of ALL.

CONCLUSION

The information gained from collaborative studies has helped decipher the heterogeneity of ALL to help improve personalized treatment, which will further advance the current high cure rate and the quality of life for children and adolescents with ALL.

EZH2 is increased in paediatric T-cell acute lymphoblastic leukemia and is a suitable molecular target in combination treatment approaches

Background

T-cell Acute Lymphoblastic Leukemia (ALL) represents about 10–15 % of pediatric ALL cases. EZH2, one of the components of Polycomb group proteins (PRC2) complex, catalyzes the trimethylation of histone H3 lysine 27 that is associated with transcriptional repression and tumor development.

Methods

We examined the expression levels of PRC2 complex in primary samples of T cells ALL at diagnosis by western blotting and real time PCR. We evaluated the effect of 3-deazaneplanocin-A (DZNep), an EZH2 inhibitor, alone and in combination with Daunoblastine on cell viability, apoptotic death and cell cycle distribution of T cell established Jurkat cell line.

Results

EZH2 was expressed in 75 % samples at different extents mainly with high expression level. SUZ12 was expressed in 60 % samples and EED in all samples, respectively. The Kaplan-Meier analysis shows that T-ALL expressing EZH2 had a lower probability of disease-free survival (DFS) compared to T-ALL negative for EZH2 (23 % vs 100 %) (p = 0.01). The EZH2 inhibitor DZNep used in combination with Daunoblastine was synergistic in inducing growth inhibition and increasing the apoptosis in T-ALL Jurkat cells at 48 and 72 h paralleled by EZH2 decreased expression. Moreover, the combination decreased the activity of Erk-1/2 proliferation enzymes with no effects on Akt survival pathway.

Conclusions

The evaluation of EZH2 expression in pediatric T-ALL can be useful in predict the clinical outcome of the patients and EZH2 can be a useful target to improve the efficacy of conventional chemotherapy in this subset of patients with bad prognosis.

Prevalence of common fusion transcripts in acute lymphoblastic leukemia: A report of 304 cases

AIM

Information about fusion transcripts in acute lymphoblastic leukemia (ALL) is used to risk-stratify patients, decide on the treatment and to detect minimal residual disease. This study was conducted to determine the frequency of common fusion transcripts BCR-ABL, TEL-AML1, MLL-AF4 and E2A-PBX1 for B-ALL and SIL-TAL1 for T-ALL as seen at a tertiary care center in India.

METHODS

Up to 304 new cases of ALL (271 B-ALL and 33 T-ALL) diagnosed on morphology, cytochemistry and immunophenotyping were studied. All were screened for the common fusion transcripts by RT-PCR.

RESULTS

Both our B- (218/271; 80.4%) and T-ALL (26/33; 78.8%) patients were largely children. In the B-ALL children, BCR-ABL was detected in 26/218 (11.9%), E2A-PBX1 in 13/218 (5.9%), TEL-AML1 in 16/218 (7.3%) and MLL-AF4 in 3/218 (1.4%) patients. Adult B-ALL cases had BCR-ABL in 15/53 (28.3%) and E2A-PBX in 2/53 (3.8%); however, no other fusion transcript was detected. SIL-TAL1 was found in four of 26 pediatric (15%) and zero of 7 adult T-ALL cases.

CONCLUSION

The higher incidence of BCR-ABL and lower incidence of TEL-AML1 in our ALL patients, both in children and adults as compared with the West, suggests that patients in India may be biologically different. This difference may explain at least in part the higher relapse rate and poorer outcome in our B-ALL cases.

Natural killer cell therapy in children with relapsed leukemia

BACKGROUND

Novel therapies are needed for children with relapsed or refractory leukemia. We therefore tested the safety and feasibility of haploidentical natural killer cell therapy in this patient population.

PROCEDURE

Twenty-nine children who had relapsed or refractory leukemia were treated with chemotherapy followed by the infusion of haploidentical NK cells. Cohort 1 included 14 children who had not undergone prior allogeneic hematopoietic cell transplantation (HCT), whereas Cohort 2 included 15 children with leukemia that had relapsed after HCT.

RESULTS

Twenty-six (90%) NK donors were KIR mismatched (14 with one KIR and 12 with 2 KIRs). The peak NK chimerism levels were >10% donor in 87% of the evaluable recipients. In Cohort 1, 10 had responsive disease and 12 proceeded to HCT thereafter. Currently, 5 (36%) are alive without leukemia. In Cohort 2, 10 had responsive disease after NK therapy and successfully proceeded to second HCT. At present, 4 (27%) are alive and leukemia-free. The NK cell infusions and the IL-2 injections were well-tolerated.

CONCLUSIONS

NK cell therapy is safe, feasible, and should be further investigated in patients with chemotherapy-resistant leukemia.

CD19-targeted chimeric antigen receptor T-cell therapy for acute lymphoblastic leukemia

Relapsed and refractory acute lymphoblastic leukemia (ALL) remains difficult to treat, with minimal improvement in outcomes seen in more than 2 decades despite advances in upfront therapy and improved survival for de novo ALL. Adoptive transfer of T cells engineered to express a chimeric antigen receptor (CAR) has emerged as a powerful targeted immunotherapy, showing striking responses in highly refractory populations. Complete remission (CR) rates as high as 90% have been reported in children and adults with relapsed and refractory ALL treated with CAR-modified T cells targeting the B-cell-specific antigen CD19. Distinct CAR designs across several studies have produced similar promising CR rates, an encouraging finding. Even more encouraging are durable remissions observed in some patients without additional therapy. Duration of remission and CAR-modified T-cell persistence require further study and more mature follow-up, but emerging data suggest these factors may distinguish CAR designs. Supraphysiologic T-cell proliferation, a hallmark of this therapy, contributes to both efficacy and the most notable toxicity, cytokine release syndrome (CRS), posing a unique challenge for toxicity management. This review will discuss the current landscape of CD19 CAR clinical trials, CRS pathophysiology and management, and remaining challenges.

Rationale for targeting the pre-B-cell receptor signaling pathway in acute lymphoblastic leukemia

Inhibitors of B-cell receptor (BCR) and pre-BCR signaling were successfully introduced into patient care for various subtypes of mature B-cell lymphoma (e.g., ibrutinib, idelalisib). Acute lymphoblastic leukemia (ALL) typically originates from pre-B cells that critically depend on survival signals emanating from a functional pre-BCR. However, whether patients with ALL benefit from treatment with (pre-) BCR inhibitors has not been explored. Recent data suggest that the pre-BCR functions as tumor suppressor in the majority of cases of human ALL. However, a distinct subset of human ALL is selectively sensitive to pre-BCR antagonists.

Stem-Cell Transplantation in Children With Acute Lymphoblastic Leukemia: A Prospective International Multicenter Trial Comparing Sibling Donors With Matched Unrelated Donors—The ALL-SCT-BFM-2003 Trial

Purpose

Although hematopoietic stem-cell transplantation is widely performed in children with high-risk acute lymphoblastic leukemia (ALL), the influence of donor types is poorly understood. Thus, transplantation outcomes were compared in the prospective multinational Berlin-Frankfurt-Muenster (BFM) study group trial: ALL-SCT-BFM 2003 (Allogeneic Stem Cell Transplantation in Children and Adolescents with Acute Lymphoblastic Leukemia).

Patients and Methods

After conditioning with total-body irradiation and etoposide, 411 children with high-risk ALL received highly standardized stem-cell transplantations during the first or later remissions. Depending on donor availability, grafts originated from HLA-genoidentical siblings or from HLA-matched unrelated donors who were identified and matched by high-resolution allelic typing and were compatible in at least 9 of 10 HLA loci.

Results

Four-year event-free survival (± standard deviation [SD]) did not differ between patients with transplantations from unrelated or sibling donors (0.67 ± 0.03 v 0.71 ± 0.05; P = .405), with cumulative incidences of nonrelapse mortality (± SD) of 0.10 ± 0.02 and 0.03 ± 0.02 (P = .017) and relapse rates (± SD) of 0.22 ± 0.02 and 0.24 ± 0.04 (P = .732), respectively. Among recipients of transplantations from unrelated donors, no significant differences in event-free survival, overall survival, or nonrelapse mortality were observed between 9/10 and 10/10 matched grafts or between peripheral blood stem cells and bone marrow. The absence of chronic graft-versus-host disease had no effect on event-free survival. Engraftment was faster after bone marrow transplantation from siblings and was associated with fewer severe infections and pulmonary complications.

Conclusion

Outcome among high-risk pediatric patients with ALL after hematopoietic stem-cell transplantation was not affected by donor type. Standardized myeloablative conditioning produced a low incidence of treatment-related mortality and effective control of leukemia.

An unusual case of phenotype switch between AML FAB subtypes

Phenotypic switch between any leukemia subtypes is of concern to a treating physician and more so, in acute myelocytic leukemia (AML) as the mechanisms for switch and subsequent chemotherapy regimen to be used remain unclear. AML-non-M3 from AML-M3 subtype needs special mention as this has been unheard off.

Treatment of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric oncologic diagnosis, and advances in its treatment have led to progressive improvements in survival. The 4 main components of therapy are remission induction, consolidation, maintenance, and central nervous system-directed therapy, and usually last 2 to 3 years. Treatment intensity based on risk-based stratification is the cornerstone of treatment. Patients with features of more favorable disease are spared the more toxic effects of chemotherapy, whereas more aggressive regimens are reserved for those with higher-risk disease. Prognosis of relapsed pediatric ALL depends primarily on duration of remission and site of relapse.

Tumour volume reduction after neoadjuvant chemotherapy impacts outcome in localised embryonal rhabdomyosarcoma

BACKGROUND

Response (tumour volume reduction) to induction chemotherapy has been used to stratify secondary local and systemic treatment of Intergroup Rhabdomyosarcoma Study Group III (IRSG-III) embryonal rhabdomyosarcoma (RME) in consecutive CWS-trials. To evaluate its actual impact we studied response-related treatment and outcomes.

PROCEDURE

Patients with IRSG-III RME <21 years and non-response (NR, <33% volume reduction) in five consecutive CWS-trials were analysed and compared with partial responders (PAR, ≥ 33% reduction). The NR was reviewed and sub-classified as Objective Response (OR, <0%-33% reduction) or Stable/Progressive Disease (SPD).

RESULTS

Fifty-nine of 529 patients had NR (n = 34 OR, n = 25 SPD). Primary risk-factors including age, tumour size, and TN-classification did not differ between NR and PAR groups but NR had more patients with unfavourable sites comparatively (P = 0.04). There were no differences in primary risk-factors between OR and SPD. Significant factors associated with poor outcome in multivariate analysis were NR, TN-classification, age >10 years, tumour size >5 cm and therapy in older trials. After response assessment n = 24 NR continued to receive induction chemotherapy, n = 32 received other combinations and n = 3 no further chemotherapy. Forty-two non-responders were irradiated, and the tumours were completely resected in n = 20. After a median follow-up of 8 years, 34 NR are alive. Seventeen of 21 failures leading to disease-related deaths were locoregional. The five-year overall survival rate (OS) was 76 ± 4% for PAR, 79 ± 14% for OR, but only 40 ± 19% for SPD (P < 0.001).

CONCLUSION

Response to induction chemotherapy appears to be an important surrogate marker of poor outcome in patients with SPD largely due to ineffective local control.

Palliative care in pediatric patients with hematologic malignancies

Children with advanced cancer, including those with hematologic malignancies, can benefit from interdisciplinary palliative care services. Palliative care includes management of distressing symptoms, attention to psychosocial and spiritual needs, and assistance with navigating complex medical decisions with the ultimate goal of maximizing the quality-of-life of the child and family. Palliative care is distinct from hospice care and can assist with the care of patients throughout the cancer continuum, irrespective of prognosis. While key healthcare organizations, including the Institute of Medicine, the American Academy of Pediatrics and the American Society of Clinical Oncology among many others endorse palliative care for children with advanced illness, barriers to integration of palliative care into cancer care still exist. Providing assistance with advance care planning, guiding patients and families through prognostic uncertainty, and managing transitions of care are also included in goals of palliative care involvement. For patients with advanced malignancy, legislation, included in the Patient Protection and Affordable Health Care Act allows patients and families more options as they make the difficult transition from disease directed therapy to care focused on comfort and quality-of-life.

Clinically defining and managing high-risk pediatric patients with acute lymphoblastic leukemia

For children with acute lymphoblastic leukemia, the identification of those at higher risk of disease recurrence and modifying therapy based on this risk is a critical component to the provision of optimal care. The specific definitions of high-risk ALL vary across cooperative groups, but the themes are consistent, being largely based on leukemia biology and disease response. Intensification of conventional chemotherapy for those with high-risk disease has led to improved outcomes. It is anticipated that the development of rational targeted therapy for specific biologically unique subsets of children with leukemia will contribute to ongoing progress in improving the outcomes for children with acute lymphoblastic anemia.

Clinically defining and managing high-risk pediatric patients with acute lymphoblastic leukemia

For children with acute lymphoblastic leukemia, the identification of those at higher risk of disease recurrence and modifying therapy based on this risk is a critical component to the provision of optimal care. The specific definitions of high-risk ALL vary across cooperative groups, but the themes are consistent, being largely based on leukemia biology and disease response. Intensification of conventional chemotherapy for those with high-risk disease has led to improved outcomes. It is anticipated that the development of rational targeted therapy for specific biologically unique subsets of children with leukemia will contribute to ongoing progress in improving the outcomes for children with acute lymphoblastic anemia.

Detection and management of minimal residual disease in acute lymphoblastic leukemia

The detection of minimal residual disease (MRD) has become part of the state-of-the-art diagnostics to guide treatment both in pediatric and adult acute lymphoblastic leukemia (ALL). This applies to the treatment of de novo and recurrent ALL. In high-risk ALL, MRD detection is considered an important tool to adjust therapy before and after hematopoietic stem cell transplantation. Precise quantification and quality control is instrumental to avoid false treatment assignment. A new methodological approach to analyzing MRD has become available and is based on next-generation sequencing. In principle, this technique will be able to detect a large number of leukemic subclones at a much higher speed than before. Carefully designed prospective studies need to demonstrate concordance or even superiority compared with those techniques in use right now: detection of aberrant expression of leukemia-specific antigens by flow cytometry of blood or bone marrow, or detection of specific rearrangements of the T-cell receptor or immunoglobulin genes by real-time quantitative polymerase chain reaction using DNA of leukemic cells. In some cases with known fusion genes, such as BCR/ABL, reverse transcriptase-polymerase chain reaction has been used as additional method to identify leukemic cells by analyzing RNA in patient samples. MRD detection may be used to modulate treatment intensity once it has been demonstrated at well-defined informative checkpoints that certain levels of MRD can reliably predict the risk of relapse. In addition, MRD is used as end point to determine the activity of a given agent or treatment protocol. If activity translates into antileukemic efficacy, MRD may be considered a surrogate clinical end point.

Risk factors for relapse in childhood acute lymphoblastic leukemia: prediction and prevention

With current treatment regimens, survival rates for acute lymphoblastic leukemia (ALL) have improved dramatically since the 1980s, with current 5-year overall survival rates estimated at greater than 85%. This success was achieved, in part, through the implementation of risk-stratified therapy. Nevertheless, for a subgroup of patients (15-20%) with newly diagnosed ALL who will ultimately relapse, traditional risk assessment remains inadequate. The risk of relapse may be estimated on the basis of diagnostic features or early treatment response findings. Further progress in this field may thus come from refinement of predictive factors for relapse and treatment adaptation and from the identification of biological subsets of ALL patients who could benefit from specific target therapies. This article summarizes the aspects associated with the identification of predictive factors for relapse in childhood ALL and options available for prevention of disease recurrence.

Acute leukemia

Although great progress has been made in the understanding and treatment of acute leukemia, this disease has not been conquered. For emergency providers (EPs), the presentation of these patients to an emergency department presents a host of challenges. A patient may present with a new diagnosis of leukemia or with complications of the disease process or associated chemotherapy. It is incumbent on EPs to be familiar with the manifestations of leukemia in its various stages and maintain some suspicion for this diagnosis, given the nebulous and insidious manner in which leukemia can present.

Long-term outcome of a pediatric-inspired regimen used for adults aged 18-50 years with newly diagnosed acute lymphoblastic leukemia

On the basis of the data suggesting that adolescents and young adult patients with acute lymphoblastic leukemia (ALL) have improved outcomes when treated on pediatric protocols, we assessed the feasibility of treating adult patients aged 18–50 years with ALL with the DFCI Pediatric ALL Consortium regimen utilizing a 30-week course of pharmacokinetically dose-adjusted E. coli L-asparaginase during consolidation. Between 2002 and 2008, 92 eligible patients aged 18–50 years were enrolled at 13 participating centers. Seventy-eight patients (85%) achieved a complete remission (CR) after 1 month of intensive induction therapy. With a median follow-up of 4.5 years, the 4-year disease-free survival (DFS) for the patients achieving a CR was 69% (95% confidence interval (CI) 56–78%) and the 4-year overall survival (OS) for all eligible patients was 67% (95% CI 56–76%). The 4-year DFS for the 64 patients who achieved a CR and were Philadelphia chromosome negative (Ph−) was 71% (95% CI 58–81%), and for all 74 Ph− patients the 4-year OS was 70% (95% CI 58–79%). We conclude that a pediatric-like treatment strategy for young adults with de novo ALL is feasible, associated with tolerable toxicity, and results in improved outcomes compared with historical regimens in young adult patients with ALL.

New frontiers in pediatric Allo-SCT: novel approaches for children and adolescents with ALL

Although most children with ALL can be cured by chemotherapy approaches, allogeneic hematopoietic cell transplant (HCT) therapy offers a better chance of cure to selected high-risk patients in first remission and most children who relapse. Although transplant-related mortality has decreased significantly in the past decade, relapse remains high after HCT for ALL; developing strategies to decrease relapse and improve survival are vital. Recent studies have shown that relapse risk can be accurately defined using measurements of minimal residual disease (MRD) both pre- and post-HCT and by knowing whether patients get GVHD in the first 2 months after transplant. With these risk definitions in hand, investigators are now applying novel agents and immunotherapeutic methods in attempt to lower MRD before transplant and modulate the GVL effect after transplant. With powerful new immunological approaches coming on line, the transplant process itself will likely expand to include pre and/or post-HCT interventions aimed at reducing relapse.

Outcome of transplantation for acute lymphoblastic leukemia in children with Down syndrome

We report on 27 patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) who received allogeneic hematopoietic cell transplantation (HCT) between 2000 and 2009. Seventy-eight percent of patients received myeloablative conditioning and 52% underwent transplantation in second remission. Disease-free survival (DFS) was 24% at a median of 3 years. Post-transplant leukemic relapse was more frequent than expected for children with DS-ALL (54%) than for non-DS ALL. These data suggest leukemic relapse rather than transplant toxicity is the most important cause of treatment failure. Advancements in leukemia control are especially needed for improvement in HCT outcomes for DS-ALL.

Minimal residual disease before and after transplantation for childhood acute lymphoblastic leukaemia: is there any room for intervention?

Eighty-two children and adolescents who underwent allogeneic transplantation for acute lymphoblastic leukaemia in remission (period 2001-2011, median follow-up 4·9 years) had been assessed for minimal residual disease (MRD) by real-time quantitative polymerase chain reaction before and at 1, 3, 6, 9 and 12 months after transplantation. Five-year event-free survival (EFS) and cumulative incidence of relapse were 77·7% [standard error (SE) 5·7] and 11·4% (SE 4·4), respectively, for patients with pre-transplant MRD <1 × 10(-4) (68%), versus 30·8% (SE 9·1; P < 0·001) and 61·5% (SE 9·5; P < 0·001), respectively, for those with MRD ≥1 × 10(-4) (32%). Pre-transplant MRD ≥1 × 10(-4) was associated with a 9·2-fold risk of relapse [95% confidence interval (CI) 3·54-23·88; P < 0·001] compared with patients with MRD <1 × 10(-4). Patients who received additional chemotherapy pre-transplant to reduce MRD had a fivefold reduction of risk of failure (hazard ratio 0·19, CI 0·05-0·70, P = 0·01). Patients who experienced MRD positivity post-transplant did not necessarily relapse (5-year EFS 40·3%, SE 9·3), but had a 2·5-fold risk of failure (CI 1·05-5·75; P = 0·04) if any MRD was detected in the first 100 d, which increased to 7·8-fold (CI 2·2-27·78; P = 0·002) if detected after 6 months. Anticipated immunosuppression-tapering according to MRD may have improved outcome, nevertheless all patients with post-transplant MRD ≥1 × 10(-3) ultimately relapsed, regardless of immunosuppression discontinuation or donor-lymphocyte-infusion. In conclusion, MRD before transplantation had the strongest impact on relapse and MRD positivity after transplantation, mostly if detected early and at low levels, did not necessarily imply relapse. Additional intensified chemotherapy and modulation of immunosuppression may reduce relapse risk and improve ultimate outcome.

The evolution of clinical trials for infant acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) in infants has a significantly inferior outcome in comparison with older children. Despite initial improvements in survival of infants with ALL since establishment of the first pediatric cooperative group ALL trials, the poor outcome has plateaued in recent years. Historically, infants were treated on risk-adapted childhood ALL protocols. These studies were pivotal in identifying the need for infant-specific protocols, delineating prognostic categories and the requirement for a more unified approach between study groups to overcome limitations in accrual because of low incidence. This subsequently led to the development of collaborative infant-specific studies. Landmark outcomes have included the elimination of cranial radiotherapy following the discovery of intrathecal and high-dose systemic therapy as a superior and effective treatment strategy for central nervous system disease prophylaxis, with improved neurodevelopmental outcome. Universal prospective identification of independent adverse prognostic factors, including presence of a mixed lineage leukemia rearrangement and young age, has established the basis for risk stratification within current trials. The infant-specific trials have defined limits to which conventional chemotherapeutic agents can be intensified to optimize the balance between treatment efficacy and toxicity. Despite variations in therapeutic intensity, there has been no recent improvement in survival due to the equilibrium between relapse and toxicity. Ultimately, to improve the outcome for infants with ALL, key areas still to be addressed include identification and adaptation of novel prognostic markers and innovative therapies, establishing the role of hematopoietic stem cell transplantation in first complete remission, treatment strategies for relapsed/refractory disease and monitoring and timely intervention of late effects in survivors. This would be best achieved through a single unified international trial.

A 50-year journey to cure childhood acute lymphoblastic leukemia

The 50th anniversary of Seminars in Hematology coincides with the 50th anniversary of St. Jude Children's Research Hospital, and both milestones are inexorably linked to studies contributing to the cure of childhood acute lymphoblastic leukemia (ALL). We thought it fitting, therefore, to mark these events by traveling back in time to point out some of the achievements, institutions, study groups, and individuals that have made cure of childhood ALL a reality. In many instances, progress was driven by new ideas, while in others it was driven by new experimental tools that allowed more precise assessment of the biology of leukemic blasts and their utility in selecting therapy. We also discuss a number of contemporary advances that point the way to exciting future directions. Whatever pathways are taken, a clear challenge will be to use emerging genome-based or immunologic-based treatment options in ways that will enhance, rather than duplicate or compromise, recent gains in outcome with classic cytotoxic chemotherapy. The theme of this journey serves as a reminder of the chief ingredient of any research directed to a catastrophic disease such as ALL. It is the audacity of a small group of investigators who confronted a childhood cancer with the goal of cure, not palliation, as their mindset.

Childhood high-risk acute lymphoblastic leukemia in first remission: results after chemotherapy or transplant from the AIEOP ALL 2000 study

Intensive BFM therapy is effective for HR childhood ALL if low MRD levels are achieved at the end of the induction/consolidation phase. Childhood ALL with high MRD levels at the end of induction/consolidation phase has a poor prognosis despite intensive BFM therapy or HSCT.

Pharmacogenetics of methotrexate in acute lymphoblastic leukaemia: why still at the bench level?

PURPOSE

The antifolate drug methotrexate (MTX) was introduced into clinical practice about 60 years ago and remains an important component of different acute lymphoblastic leukemia (ALL) treatment protocols. It acts by inhibiting several enzymes in the folate pathway, thereby resulting in the disruption of folate homeostasis. To date, treatment regimens have not been personalized despite there being experimental evidence that gene polymorphisms of folate metabolizing enzymes affect MTX response. The aim of this review was to evaluate the influence of genetic polymorphisms of the enzymes involved in the MTX pathway on ALL treatment outcomes and identify factors underlining the failure to personalize MTX therapy.

METHODS

We conducted a literature search in PUBMED and Google Scholar using the following key words: methotrexate, polymorphism, acute lymphoblastic leukemia, pharmacogenetics, pharmacogenomics and personalized medicine.

RESULTS

The reasons for the failure to personalize MTX therapy may be due to (1) most studies involving single-center, small-sized cohorts, (2) differences in MTX dose across different protocols, (3) failure to consider minimal residual disease as a risk factor for post-induction treatment, (4) differences in outcome criteria between studies and (5) failure to consider the folate levels of a patient before initiation of MTX therapy. Although high-throughput techniques allow the mapping of thousands of genetic polymorphisms in a single run, it remains a major challenge to dissect out folate-metabolizing enzymes which have a high impact on the efficacy and toxicity of MTX and which, therefore, could be the targets for intervention.

CONCLUSIONS

Prospective pharmacogenetic studies which consider all of the above-mentioned factors should be undertaken to facilitate the design of personalized MTX treatment for ALL patients.

Metabolomics of the tumor microenvironment in pediatric acute lymphoblastic leukemia

The tumor microenvironment is emerging as an important therapeutic target. Most studies, however, are focused on the protein components, and relatively little is known of how the microenvironmental metabolome might influence tumor survival. In this study, we examined the metabolic profiles of paired bone marrow (BM) and peripheral blood (PB) samples from 10 children with acute lymphoblastic leukemia (ALL). BM and PB samples from the same patient were collected at the time of diagnosis and after 29 days of induction therapy, at which point all patients were in remission. We employed two analytical platforms, high-resolution magnetic resonance spectroscopy and gas chromatography-mass spectrometry, to identify and quantify 102 metabolites in the BM and PB. Standard ALL therapy, which includes l-asparaginase, completely removed circulating asparagine, but not glutamine. Statistical analyses of metabolite correlations and network reconstructions showed that the untreated BM microenvironment was characterized by a significant network-level signature: a cluster of highly correlated lipids and metabolites involved in lipid metabolism (p<0.006). In contrast, the strongest correlations in the BM upon remission were observed among amino acid metabolites and derivatives (p<9.2 × 10(-10)). This study provides evidence that metabolic characterization of the cancer niche could generate new hypotheses for the development of cancer therapies.

Influence of length of time to diagnosis and treatment on the survival of children with acute lymphoblastic leukemia: a population-based study

The objectives were to describe times to diagnosis and initiation of treatment in pediatric ALL in Ontario from 1997 to 2007, and to measure their impact on OS and EFS. In 1000 children, the median times to diagnosis and treatment were both 1 day (IQR = 1-2). Those who began treatment >3 days after diagnosis had inferior OS (AHR = 2.49; 95% CI = 1.40-4.43; p = 0.002), and inferior EFS (AHR = 1.73; 95% CI = 1.01-2.96; p = 0.047) compared to those who began treatment ≤ 3 days after diagnosis. There was no statistically significant relationship between time to diagnosis and survival. Longer time to treatment was associated with worse survival in pediatric ALL; reasons for this relationship may be multi-factorial.

Array comparative genomic hybridization in pediatric acute leukemias

Array comparative genomic hybridization has proven to be a very powerful tool in searching for new biomarkers which can find an application in clinical practise. CGH-array technology is satisfying in almost every possible way. It is highly specific, sensitive, simple, and relatively cheap. Thus, this modern method meets the demands of clinical application. An increasing knowledge about molecular pathways and pathologic genome alterations in acute leukemias enable to define unequivocal diagnosis, prognosis and to predict a response to individual compatible therapy. This review shows a various application of CGH-array in pediatric acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).

An international study of intrachromosomal amplification of chromosome 21 (iAMP21): cytogenetic characterization and outcome

Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.

Par-4/THAP1 complex and Notch3 competitively regulated pre-mRNA splicing of CCAR1 and affected inversely the survival of T-cell acute lymphoblastic leukemia cells

Although the intensification of therapy for children with T-cell acute lymphoblastic leukemia (T-ALL) has substantially improved clinical outcomes, T-ALL remains an important challenge in pediatric oncology. Here, we report that the cooperative synergy between prostate apoptosis response factor-4 (Par-4) and THAP1 induces cell cycle and apoptosis regulator 1 (CCAR1) gene expression and cellular apoptosis in human T-ALL cell line Jurkat cells, CEM cells and primary cultured neoplastic T lymphocytes from children with T-ALL. Par-4 and THAP1 collaborated to activate the promoter of CCAR1 gene. Mechanistic investigations revealed that Par-4 and THAP1 formed a protein complex by the interaction of their carboxyl termini, and THAP1 bound to CCAR1 promoter though its zinc-dependent DNA-binding domain at amino terminus. Par-4/THAP1 complex and Notch3 competitively bound to CCAR1 promoter and competitively modulated alternative pre-mRNA splicing of CCAR1, which resulted in two different transcripts and played an opposite role in T-ALL cell survival. Despite Notch3 induced a shift splicing from the full-length isoform toward a shorter form of CCAR1 mRNA by splicing factor SRp40 and SRp55, Par-4/THAP1 complex strongly antagonized this inductive effect. Our finding revealed a mechanistic rationale for Par-4/THAP1-induced apoptosis in T-ALL cells that would be of benefit to develop a new therapy strategy for T-ALL.

Challenges and opportunities for international cooperative studies in pediatric hematopoeitic cell transplantation: priorities of the Westhafen Intercontinental Group

More than 20% of allogeneic hematopoietic cell transplantations (HCTs) are performed in children and adolescents at a large number of relatively small centers. Unlike adults, at least one-third of HCTs in children are performed for rare, nonmalignant indications. Clinical trials to improve HCT outcomes in children have been limited by small numbers and these pediatric-specific features. The need for a larger number of pediatric HCT centers to participate in trials has led to the involvement of international collaborative groups. Representatives of the Pediatric Blood and Marrow Transplant Consortium, European Group for Blood and Marrow Transplantation's Pediatric Working Group, International Berlin-Frankfurt-Munster (iBFm) Stem Cell Transplantation Committee, and Children's Oncology Group's Hematopoietic Stem Cell Transplantation Discipline Committee met on October 3, 2012, in Frankfurt, Germany to develop a consensus on the highest priorities in pediatric HCT. In addition, it explored the creation of an international consortium to develop studies focused on HCT in children and adolescents. This meeting led to the creation of an international HCT network, dubbed the Westhafen Intercontinental Group, to develop worldwide priorities and strategies to address pediatric HCT issues. This review outlines the priorities of need as identified by this consensus group.

Predicting relapse risk in childhood acute lymphoblastic leukaemia

Intensive multi-agent chemotherapy regimens and the introduction of risk-stratified therapy have substantially improved cure rates for children with acute lymphoblastic leukaemia (ALL). Current risk allocation schemas are imperfect, as some children are classified as lower-risk and treated with less intensive therapy relapse, while others deemed higher-risk are probably over-treated. Most cooperative groups previously used morphological clearance of blasts in blood and marrow during the initial phases of chemotherapy as a primary factor for risk group allocation; however, this has largely been replaced by the detection of minimal residual disease (MRD). Other than age and white blood cell count (WBC) at presentation, many clinical variables previously used for risk group allocation are no longer prognostic, as MRD and the presence of sentinel genetic lesions are more reliable at predicting outcome. Currently, a number of sentinel genetic lesions are used by most cooperative groups for risk stratification; however, in the near future patients will probably be risk-stratified using genomic signatures and clustering algorithms, rather than individual genetic alterations. This review will describe the clinical, biological, and response-based features known to predict relapse risk in childhood ALL, including those currently used and those likely to be used in the near future to risk-stratify therapy.

Children's Oncology Group's 2013 blueprint for research: acute lymphoblastic leukemia

Approximately 90% of the 2,000 children, adolescents, and young adults enrolled each year in Children's Oncology Group acute lymphoblastic leukemia (ALL) trials will be cured. However, high-risk subsets with significantly inferior survival remain, including infants, newly diagnosed patients with age ≥10 years, white blood count ≥50,000/µl, poor early response or T-cell ALL, and relapsed ALL patients. Effective strategies to improve survival include better risk stratification, optimizing standard chemotherapy and combining targeted therapies with cytotoxic chemotherapy, the latter of which is dependent upon identification of key driver mutations present in ALL.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia occurs in both children and adults but its incidence peaks between 2 and 5 years of age. Causation is multifactorial and exogenous or endogenous exposures, genetic susceptibility, and chance have roles. Survival in paediatric acute lymphoblastic leukaemia has improved to roughly 90% in trials with risk stratification by biological features of leukaemic cells and response to treatment, treatment modification based on patients' pharmacodynamics and pharmacogenomics, and improved supportive care. However, innovative approaches are needed to further improve survival while reducing adverse effects. Prognosis remains poor in infants and adults. Genome-wide profiling of germline and leukaemic cell DNA has identified novel submicroscopic structural genetic changes and sequence mutations that contribute to leukaemogenesis, define new disease subtypes, affect responsiveness to treatment, and might provide novel prognostic markers and therapeutic targets for personalised medicine.

Second malignant neoplasms after treatment of childhood acute lymphoblastic leukemia

PURPOSE

Second malignant neoplasms (SMNs) after diagnosis of childhood acute lymphoblastic leukemia (ALL) are rare events.

PATIENTS AND METHODS

We analyzed data on risk factors and outcomes of 642 children with SMNs occurring after treatment for ALL from 18 collaborative study groups between 1980 and 2007.

RESULTS

Acute myeloid leukemia (AML; n = 186), myelodysplastic syndrome (MDS; n = 69), and nonmeningioma brain tumor (n = 116) were the most common types of SMNs and had the poorest outcome (5-year survival rate, 18.1% ± 2.9%, 31.1% ± 6.2%, and 18.3% ± 3.8%, respectively). Five-year survival estimates for AML were 11.2% ± 2.9% for 125 patients diagnosed before 2000 and 34.1% ± 6.3% for 61 patients diagnosed after 2000 (P < .001); 5-year survival estimates for MDS were 17.1% ± 6.4% (n = 36) and 48.2% ± 10.6% (n = 33; P = .005). Allogeneic stem-cell transplantation failed to improve outcome of secondary myeloid malignancies after adjusting for waiting time to transplantation. Five-year survival rates were above 90% for patients with meningioma, Hodgkin lymphoma, thyroid carcinoma, basal cell carcinoma, and parotid gland tumor, and 68.5% ± 6.4% for those with non-Hodgkin lymphoma. Eighty-nine percent of patients with brain tumors had received cranial irradiation. Solid tumors were associated with cyclophosphamide exposure, and myeloid malignancy was associated with topoisomerase II inhibitors and starting doses of methotrexate of at least 25 mg/m(2) per week and mercaptopurine of at least 75 mg/m(2) per day. Myeloid malignancies with monosomy 7/5q- were associated with high hyperdiploid ALL karyotypes, whereas 11q23/MLL-rearranged AML or MDS was associated with ALL harboring translocations of t(9;22), t(4;11), t(1;19), and t(12;21) (P = .03).

CONCLUSION

SMNs, except for brain tumors, AML, and MDS, have outcomes similar to their primary counterparts.

O-acetylated N-acetylneuraminic acid as a novel target for therapy in human pre-B acute lymphoblastic leukemia

Removal of 9-O-acetyl residues from the cell surface N-acetylneuraminic acid makes ALL cells drug sensitive.

The development of resistance to chemotherapy is a major cause of relapse in acute lymphoblastic leukemia (ALL). Though several mechanisms associated with drug resistance have been studied in detail, the role of carbohydrate modification remains unexplored. Here, we investigated the contribution of 9-O-acetylated N-acetylneuraminic acid (Neu5Ac) to survival and drug resistance development in ALL cells. A strong induction of 9-O-acetylated Neu5Ac including 9-O-acetyl GD3 was detected in ALL cells that developed resistance against vincristine or nilotinib, drugs with distinct cytotoxic mechanisms. Removal of 9-O-acetyl residues from Neu5Ac on the cell surface by an O-acetylesterase made ALL cells more vulnerable to such drugs. Moreover, removal of intracellular and cell surface–resident 9-O-acetyl Neu5Ac by lentiviral transduction of the esterase was lethal to ALL cells in vitro even in the presence of stromal protection. Interestingly, expression of the esterase in normal fibroblasts or endothelial cells had no effect on their survival. Transplanted mice induced for expression of the O-acetylesterase in the ALL cells exhibited a reduction of leukemia to minimal cell numbers and significantly increased survival. This demonstrates that Neu5Ac 9-O-acetylation is essential for survival of these cells and suggests that Neu5Ac de-O-acetylation could be used as therapy to eradicate drug-resistant ALL cells.

Hematopoietic stem cell transplantation for children with high-risk acute lymphoblastic leukemia in first complete remission: a report from the AIEOP registry

Children with high-risk acute lymphoblastic leukemia in first complete remission can benefit from allogeneic hematopoietic stem cell transplantation. We analyzed the outcome of 211 children with high-risk acute lymphoblastic leukemia in first complete remission who were given an allogeneic transplant between 1990 and 2008; the outcome of patients who, despite having an indication for transplantation and a suitable donor, did not receive the allograft for different reasons in the same time period was not analyzed. Sixty-nine patients (33%) were transplanted between 1990 and 1999, 58 (27%) between 2000 and 2005, and 84 (40%) between 2005 and 2008. A matched family donor was employed in 138 patients (65%) and an unrelated donor in 73 (35%). The 10-year probabilities of overall and disease-free survival were 63.4% and 61%, respectively. The 10-year cumulative incidences of transplantation-related mortality and relapse were 15% and 24%, respectively. After 1999, no differences in either disease-free survival or transplant-related mortality were observed in patients transplanted from unrelated or matched family donors. In multivariate analysis, grade IV acute graft-versus-host disease was an independent factor associated with worse disease-free survival. By contrast, grade I acute graft-versus-host disease and age at diagnosis between 1 and 9 years were favorable prognostic variables. Our study, not intended to evaluate whether transplantation is superior to chemotherapy for children with acute lymphoblastic leukemia in first complete remission and high-risk features, shows that the allograft cured more than 60% of these patients; in the most recent period, the outcome of recipients of grafts from matched family and unrelated donors was comparable.

Cost-analysis of treatment of childhood acute lymphoblastic leukemia with asparaginase preparations: the impact of expensive chemotherapy

Asparaginase is an expensive drug, but important in childhood acute lymphoblastic leukemia. In order to compare costs of PEGasparaginase, Erwinia asparaginase and native E. coli asparaginase, we performed a cost-analysis in the Dutch Childhood Oncology Group ALL-10 medium-risk group intensification protocol. Treatment costs were calculated based on patient level data of 84 subjects, and were related to the occurrence of allergy to PEGasparaginase. Simultaneously, decision tree and sensitivity analyses were conducted. The total costs of the intensification course of 30 weeks were $57,893 in patients without PEGasparaginase allergy (n=64). The costs were significantly higher ($113,558) in case of allergy (n=20) necessitating a switch to Erwinia asparaginase. Simulated scenarios (decision tree analysis) using native E. coli asparaginase in intensification showed that the costs of PEGasparaginase were equal to those of native E. coli asparaginase. Also after sensitivity analyses, the costs for PEGasparaginase were equal to those of native E. coli asparaginase. Intensification treatment with native E. coli asparaginase, followed by a switch to PEGasparaginase, and subsequently to Erwinia asparaginase in case of allergy had similar overall costs compared to the treatment with PEGasparaginase as the first-line drug (followed by Erwinia asparaginase in the case of allergy). PEGasparaginase is preferred over native E. coli asparaginase, because it is administered less frequently, with less day care visits. PEGasparaginase is less immunogenic than native E. coli asparaginase and is not more expensive. Asparaginase costs are mainly determined by the percentage of patients who are allergic and require a switch to Erwinia asparaginase.

Criteria for and outcomes of allogeneic haematopoietic stem cell transplant in children, adolescents and young adults with acute lymphoblastic leukaemia in first complete remission

Most children, adolescents and young adults with acute lymphoblastic leukaemia (ALL) in first complete remission (CR1) have an excellent prognosis with multi-agent chemotherapy in induction, consolidation, re-induction and maintenance therapy. However, there is a subset of patients with a more guarded prognosis using this approach, who may benefit from haematopoietic allogeneic stem cell transplantation (alloHSCT). Commonly used criteria for alloHSCT in children, adolescents and young adults with ALL in CR1 include: induction failure, poor cytogenetics, persistent minimal residual disease (MRD), age, immunophenotype, white blood cell count at diagnosis and rapidity of induction response. Two-year event-free survival following alloHSCT in patients with ALL in CR1 ranges from 50 to 80% depending on disease status, donor source, conditioning therapy, age and other risk factors. Future studies should focus on more precisely identifying poor-risk features, such as disease genomics and host pharmacogenomics, refining MRD measurements, improving unrelated donor matching, reducing MRD prior to alloHSCT, and developing post-alloHSCT humoral and cellular therapy approaches.