The genetic basis and cell of origin of mixed phenotype acute leukaemia.

Mixed phenotype acute leukaemia (MPAL) is a high-risk subtype of leukaemia with myeloid and lymphoid features, limited genetic characterization, and a lack of consensus regarding appropriate therapy. Here we show that the two principal subtypes of MPAL, T/myeloid (T/M) and B/myeloid (B/M), are genetically distinct. Rearrangement of ZNF384 is common in B/M MPAL, and biallelic WT1 alterations are common in T/M MPAL, which shares genomic features with early T-cell precursor acute lymphoblastic leukaemia. We show that the intratumoral immunophenotypic heterogeneity characteristic of MPAL is independent of somatic genetic variation, that founding lesions arise in primitive haematopoietic progenitors, and that individual phenotypic subpopulations can reconstitute the immunophenotypic diversity in vivo. These findings indicate that the cell of origin and founding lesions, rather than an accumulation of distinct genomic alterations, prime tumour cells for lineage promiscuity. Moreover, these findings position MPAL in the spectrum of immature leukaemias and provide a genetically informed framework for future clinical trials of potential treatments for MPAL.

Symptom management care pathway adaptation process and specific adaptation decisions.

BACKGROUND: There is substantial heterogeneity in symptom management provided to pediatric patients with cancer. The primary objective was to describe the adaptation process and specific adaptation decisions related to symptom management care pathways based on clinical practice guidelines. The secondary objective evaluated if institutional factors were associated with adaptation decisions. METHODS: Fourteen previously developed symptom management care pathway templates were reviewed by an institutional adaptation team composed of two clinicians at each of 10 institutions. They worked through each statement for all care pathway templates sequentially. The institutional adaptation team made the decision to adopt, adapt or reject each statement, resulting in institution-specific symptom management care pathway drafts. Institutional adaption teams distributed the 14 care pathway drafts to their respective teams; their feedback led to care pathway modifications. RESULTS: Initial care pathway adaptation decision making was completed over a median of 4.2 (interquartile range 2.0-5.3) weeks per institution. Across all institutions and among 1350 statements, 551 (40.8%) were adopted, 657 (48.7%) were adapted, 86 (6.4%) were rejected and 56 (4.1%) were no longer applicable because of a previous decision. Most commonly, the reason for rejection was not agreeing with the statement (70/86, 81.4%). Institutional-level factors were not significantly associated with statement rejection. CONCLUSIONS: Acceptability of the 14 care pathways was evident by most statements being adopted or adapted. The adaptation process was accomplished over a relatively short timeframe. Future work should focus on evaluation of care pathway compliance and determination of the impact of care pathway-consistent care on patient outcomes. TRIAL REGISTRATION: clinicaltrials.gov, NCT04614662. Registered 04/11/2020, https://clinicaltrials.gov/ct2/show/NCT04614662?term=NCT04614662&draw=2&rank=1 .

Reevaluation of sodium thiosulfate otoprotection using the consensus International Society of Paediatric Oncology Ototoxicity Scale: A report from the Children's Oncology Group study ACCL0431.

In two randomized trials (Children's Oncology Group ACCL0431 and International Childhood Liver Tumour Strategy Group SIOPEL-6), sodium thiosulfate (STS) demonstrated efficacy in preventing cisplatin-induced hearing loss (CIHL). However, the measures used in those trials have been superseded by the consensus International Society of Paediatric Oncology (SIOP) Ototoxicity Scale. To provide benchmark data for STS efficacy when using this contemporary scale, we reanalyzed ACCL0431 hearing outcomes with the SIOP scale and using multiple timepoints. Compared to the control arm, STS significantly reduced CIHL when assessed by the SIOP scale across these different approaches. These results provide critical data to inform treatment discussions and support future potential trial designs comparing otoprotectants.

Dose-limiting mucositis: friend or foe?

Dose-limiting toxicities are ubiquitous to cancer-directed therapy, presenting with severity to a degree that necessitates therapy de-escalation, pause, or discontinuation. To date, there is incredible limited understanding if these therapy de-escalations present risk for survival by limiting delivery of intensive therapy, or if they indicate physiologic susceptibility and are a favorable prognostic indicator. Mucositis is an excellent illustration of the current paradox of dose-limiting toxicities-it has existed alongside therapy for eight decades, but despite its presence, there is an incomplete understanding of how it develops, why it varies between oncologic populations, and if it relates to cancer survival. Rigorous methodologic approaches in symptom science holds potential to better understand mucositis, to determine if it is a marker of response or threat, and evaluate if it holds potential to guide therapy delivery.

Integrin α6 mediates the drug resistance of acute lymphoblastic B-cell leukemia.

Resistance to multimodal chemotherapy continues to limit the prognosis of acute lymphoblastic leukemia (ALL). This occurs in part through a process called adhesion-mediated drug resistance, which depends on ALL cell adhesion to the stroma through adhesion molecules, including integrins. Integrin α6 has been implicated in minimal residual disease in ALL and in the migration of ALL cells to the central nervous system. However, it has not been evaluated in the context of chemotherapeutic resistance. Here, we show that the anti-human α6-blocking Ab P5G10 induces apoptosis in primary ALL cells in vitro and sensitizes primary ALL cells to chemotherapy or tyrosine kinase inhibition in vitro and in vivo. We further analyzed the underlying mechanism of α6-associated apoptosis using a conditional knockout model of α6 in murine BCR-ABL1+ B-cell ALL cells and showed that α6-deficient ALL cells underwent apoptosis. In vivo deletion of α6 in combination with tyrosine kinase inhibitor (TKI) treatment was more effective in eradicating ALL than treatment with a TKI (nilotinib) alone. Proteomic analysis revealed that α6 deletion in murine ALL was associated with changes in Src signaling, including the upregulation of phosphorylated Lyn (pTyr507) and Fyn (pTyr530). Thus, our data support α6 as a novel therapeutic target for ALL.

Temsirolimus combined with cyclophosphamide and etoposide for pediatric patients with relapsed/refractory acute lymphoblastic leukemia: a Therapeutic Advances in Childhood Leukemia Consortium trial (TACL 2014-001).

Phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling is commonly dysregulated in acute lymphoblastic leukemia (ALL). The TACL2014-001 phase I trial of the mTOR inhibitor temsirolimus in combination with cyclophosphamide and etoposide was performed in children and adolescents with relapsed/refractory ALL. Temsirolimus was administered intravenously (IV) on days 1 and 8 with cyclophosphamide 440 mg/m2 and etoposide 100 mg/m2 IV daily on days 1-5. The starting dose of temsirolimus was 7.5 mg/m2 (DL1) with escalation to 10 mg/m2 (DL2), 15 mg/m2 (DL3), and 25 mg/m2 (DL4). PI3K/mTOR pathway inhibition was measured by phosphoflow cytometry analysis of peripheral blood specimens from treated patients. Sixteen heavily-pretreated patients were enrolled with 15 evaluable for toxicity. One dose-limiting toxicity of grade 4 pleural and pericardial effusions occurred in a patient treated at DL3. Additional dose-limiting toxicities were not seen in the DL3 expansion or DL4 cohort. Grade 3/4 non-hematologic toxicities occurring in three or more patients included febrile neutropenia, elevated alanine aminotransferase, hypokalemia, mucositis, and tumor lysis syndrome and occurred across all doses. Response and complete were observed at all dose levels with a 47% overall response rate and 27% complete response rate. Pharmacodynamic correlative studies demonstrated dose-dependent inhibition of PI3K/mTOR pathway phosphoproteins in all studied patients. Temsirolimus at doses up to 25 mg/m2 with cyclophosphamide and etoposide had an acceptable safety profile in children with relapsed/refractory ALL. Pharmacodynamic mTOR target inhibition was achieved and appeared to correlate with temsirolimus dose. Future testing of next-generation PI3K/mTOR pathway inhibitors with chemotherapy may be warranted to increase response rates in children with relapsed/refractory ALL.

Mixed Phenotype Acute Leukemia: Current Approaches to Diagnosis and Treatment.

PURPOSE OF REVIEW: Mixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia with features of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The review examines current definitions and controversies in classification of MPAL, new insights into genomic drivers and pathogenesis, recent evidence to support treatment recommendations, and opportunities for future research. RECENT FINDINGS: Recent collaborative efforts have made progress in understanding the genomic landscape and optimal therapy for MPAL. The preponderance of retrospective data supports beginning therapy with ALL directed regimens. Differences in prognosis for adult and children with MPAL have led to divergent approaches for therapy intensity, including use of stem cell transplantation consolidation. MPAL remains a challenging leukemia to understand, research, and treat due to low incidence, shifting and subjective approaches to classification, and innate biological heterogeneity. Ongoing research hopes to surmount these obstacles through prospective studies within large cooperative groups to provide new insight into targetable biology and further refine optimal therapy.

Association of body mass index with toxicity and survival in pediatric patients treated with cisplatin-containing regimens.

Malnutrition is associated with treatment-related toxicities (TRT) in adults with solid tumors and in children with leukemia. Few studies have assessed whether malnutrition in pediatric patients treated for solid tumors impacts risk for TRT, relapse, and/or survival. To address this knowledge gap, this retrospective study evaluated the association between body mass index (BMI) at diagnosis, and imputed BMI during therapy, on the prevalence of TRT, specific toxicities, relapse, and survival in pediatric patients with solid tumors treated with cisplatin-containing regimens. Kaplan-Meier curves and regression models evaluated the association between patient-specific characteristics (including BMI) and TRT, relapse, and survival. The cohort included 221 patients, of whom 22% were malnourished at diagnosis (10% were underweight and 12% were obese). Most patients (60%) experienced at least one severe TRT, and 30% developed more than one severe TRT. Most patients with obesity at diagnosis remained obese during therapy (62%). In multivariable analysis, obesity at diagnosis was significantly associated with a more than threefold greater risk for developing severe TRT (p = 0.037), specifically for acute or chronic kidney injury (p = 0.014). Obesity at diagnosis and adolescent and young adult age (≥15 years at diagnosis) were associated with worse event-free survival (hazard ratio [HR] 2.32, p = 0.024 and HR 2.28, p = 0.010, respectively) and overall survival (HR 3.69, p = 0.006 and HR 2.6, p = 0.012, respectively). Obese and older patients therefore constitute populations at risk for poorer outcomes. Prospective studies are warranted to gain further insight into the mechanism and role of obesity and adolescence in developing TRT and/or treatment failure.

Improving the Timeliness of Chemotherapy Administration in the Bone Marrow Transplant Unit.

Patients undergoing hematopoietic stem cell transplantation (HSCT) are often admitted to the hospital the day they are due to begin their conditioning regimen. Timely initiation of chemotherapy during regular work hours is important for patient safety, because during the night shift fewer physicians and pharmacists are available for urgent or unexpected matters. A review of the data at our institution from October 2017 to August 2018 showed that approximately one-third of our chemotherapy was started during the night shift (after 19:00), and the average time from admission to start of chemotherapy was over 8 hours. There are currently no well-defined benchmarks for timeliness of chemotherapy initiation. The aim of this quality improvement initiative was to increase the percentage of patients who start chemotherapy in the bone marrow transplant unit before 19:00 from 65% to >80% by March 31, 2019. We identified barriers to timely initiation of chemotherapy through process mapping and analysis of failures. The primary barriers were late admissions (after 12:00 pm) and time from admission to preparation of chemotherapy. We addressed mechanisms to mitigate these barriers through Plan-Do-Study-Act testing. Interventions included providing families specific admission times and their rationales and process for notifying pharmacy of admissions immediately on arrival. We used standardized control charts to measure the impact of the interventions on change. We also monitored medication errors before and during the intervention. From September 2018 to March 2019 the percentage of patients who started preparative chemotherapy before 19:00 increased from 65% to 85%, the percentage of patients who were admitted after 12:00 remained similar before (31%) and after the interventions (33%), and the average time from admission to start of chemotherapy decreased from 8.6 hours (513 minutes) to 6.4 hours (382 minutes). Medication errors were similar before (n = 50) and after the interventions (n = 43). Using standardized processes, we demonstrated a substantial decrease in the percentage of HSCT patients starting their preparative regimen after 19:00 without a concurrent increase in errors. We believe these interventions and measurements can be used in all transplant centers and have the potential to influence patient safety and outcomes.

Association between Vitamin D and Risk for Early and Late Post-Transplant Complications.

Vitamin D (VD) deficiency is a well-described phenomenon in pediatric patients undergoing hematopoietic stem cell transplant (HSCT). VD modulates inflammation, and deficiency pre-HSCT and at day +100 has been associated with graft-versus-host disease (GVHD) and poorer survival. However, a paucity of data has specifically described the association between VD status and immune-mediated complications including GVHD and veno-occlusive disease (VOD). Additionally, data to guide recommendations for VD monitoring and supplementation during HSCT are scarce. Our primary objective was to evaluate the association between VD and post-HSCT complications. The key secondary aim was to evaluate the routine use and efficacy of VD monitoring and supplementation practices. To our knowledge, this is the largest study of its kind in the pediatric population. This retrospective study evaluated VD level (VDL) before and 1 year after HSCT, VD supplementation practices, and their association with acute GVHD, VOD, and survival in pediatric patients who received autologous and allogeneic HSCT for both malignant and nonmalignant diseases from January 2013 to April 2018. Of 314 HSCTs, 43% of patients (n = 136) had VDL measured before HSCT; 61% of this cohort had pre-HSCT VD insufficiency (<30 ng/mL). Neither pre-HSCT nor follow-up VDL was associated with the incidence of GVHD or VOD. Supplementation did not result in significantly different post-HSCT VDL.VDL was correlated with overall survival; every 10-ng/mL increase in VDL was associated with a 28% decreased risk of death (P = .01). Current accepted VD supplementation regimens for pediatric HSCT do not achieve sufficient VDL in most patients after HSCT. VD status was associated with all-cause mortality but not with individual comorbidities; prospective studies are required to establish the connection between VD status, inflammatory-mediated HSCT complications, and potential benefit of VD supplementation before and after HSCT. These studies are needed to inform evidence-based guidelines for monitoring and supplementing VD during HSCT.

Mixed-phenotype acute leukemia: A cohort and consensus research strategy from the Children's Oncology Group Acute Leukemia of Ambiguous Lineage Task Force.

BACKGROUND: Optimal chemotherapy for treating mixed-phenotype acute leukemia (MPAL) and the role of hematopoietic stem cell transplantation (HSCT) remain uncertain. Major limitations in interpreting available data are MPAL's rarity and the use of definitions other than the currently widely accepted criteria: the World Health Organization 2016 (WHO2016) classification. METHODS: To assess the relative efficacy of chemotherapy types for treating pediatric MPAL, the Children's Oncology Group (COG) Acute Leukemia of Ambiguous Lineage Task Force assembled a retrospective cohort of centrally reviewed WHO2016 MPAL cases selected from banking studies for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Patients were not treated in COG trials; treatment and outcome data were captured separately. The findings were then integrated with the available, mixed literature to develop a prospective trial in pediatric MPAL. RESULTS: The central review confirmed that 54 of 70 cases fulfilled WHO2016 criteria for MPAL. ALL induction regimens achieved remission in 72% of the cases (28 of 39), whereas AML regimens achieved remission in 69% (9 of 13). The 5-year event-free survival (EFS) and overall survival (OS) rates for the entire cohort were 72% ± 8% and 77% ± 7%, respectively. EFS and OS were 75% ± 13% and 84% ± 11%, respectively, for those receiving ALL chemotherapy alone without HSCT (n = 21). CONCLUSIONS: The results of the COG MPAL cohort and a literature review suggest that ALL chemotherapy without HSCT may be the preferred initial therapy. A prospective trial within the COG is proposed to investigate this approach; AML chemotherapy and/or HSCT will be reserved for those with treatment failure as assessed by minimal residual disease. Embedded biology studies will provide further insight into MPAL genomics.

Assessment of provider perspectives on otoprotection research for children and adolescents: A Children's Oncology Group Cancer Control and Supportive Care Committee survey.

BACKGROUND: Cisplatin-induced hearing loss (CIHL) is a common and debilitating toxicity for childhood cancer survivors. Understanding provider perspectives is crucial to developing otoprotection studies that are both informative and feasible. Two international trials (ACCL0431 and SIOPEL6) investigated the drug sodium thiosulfate (STS) as an otoprotectant, but definitive interpretation of the findings of these trials has been challenging. Adoption of STS has therefore been uneven, and provider perspectives on its role are unknown. PROCEDURE: The Children's Oncology Group (COG) Cancer Control and Supportive Care Neurotoxicity Subcommittee therefore conducted a survey of providers at COG institutions to determine perspectives on pediatric otoprotection practices and research surrounding three major themes: (1) prevalence of routine use of STS with cisplatin-based regimens, (2) application of audiometry to cisplatin therapy, and (3) preferred modalities for otoprotection research. RESULTS: Survey respondents (45%, 44/98 surveyed institutions) were of diverse institutional sizes, practice settings, and geographical locations primarily in the United States and Canada. Overall, respondents considered CIHL an important toxicity and indicated strong enthusiasm for future studies (98%, 40/41). Results indicated that while STS was the current or planned standard of care in a minority of responding institutions (36%, 16/44), most sites were receptive to its inclusion in appropriate study designs. Application of audiometry for ototoxicity monitoring varied widely across sites. For otoprotection research, systemic agents were preferred (68%, 28/41) as compared with intratympanic approaches. CONCLUSION: These results suggest that pediatric otoprotection trials remain of interest to providers; the emphasis of these trials should remain on systemic and not intratympanic therapy.

Recommendations for ototoxicity surveillance for childhood, adolescent, and young adult cancer survivors: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCare Consortium.

Childhood, adolescent, and young adult (CAYA) cancer survivors treated with platinum-based drugs, head or brain radiotherapy, or both have an increased risk of ototoxicity (hearing loss, tinnitus, or both). To ensure optimal care and reduce consequent problems-such as speech and language, social-emotional development, and learning difficulties-for these CAYA cancer survivors, clinical practice guidelines for monitoring ototoxicity are essential. The implementation of surveillance across clinical settings is hindered by differences in definitions of hearing loss, recommendations for surveillance modalities, and remediation. To address these deficiencies, the International Guideline Harmonization Group organised an international multidisciplinary panel, including 32 experts from ten countries, to evaluate the quality of evidence for ototoxicity following platinum-based chemotherapy and head or brain radiotherapy, and formulate and harmonise ototoxicity surveillance recommendations for CAYA cancer survivors.

Association of clinical trial enrollment and survival using contemporary therapy for pediatric acute lymphoblastic leukemia.

While early studies reported superior survival for cancer patients enrolled on clinical trials, recent findings are inconclusive. We investigated the association between enrollment on contemporary trials and event-free survival (EFS) in pediatric B-cell acute lymphoblastic leukemia (B-ALL). In a retrospective cohort of 274 children (1-21 years) treated for B-ALL from 2008 to 2015, 55.5% enrolled with no disparity in enrollment by age, sex, or ethnicity. Three-year EFS was similar for enrolled and not enrolled patients (90.1% [95% CI, 82.5-94.5] versus 86.5% [95% CI, 77.7-92.0]). Clinical trial enrollment did not affect pediatric B-ALL survival, albeit in a limited-size cohort treated at a single academic institution.

Predictors of hepatotoxicity and pancreatitis in children and adolescents with acute lymphoblastic leukemia treated according to contemporary regimens.

BACKGROUND: Hepatotoxicity and pancreatitis are common treatment-related toxicities (TRTs) during contemporary treatment regimens for acute lymphoblastic leukemia (ALL). Limited detailed data from Children's Oncology Group (COG) regimens has been previously reported to enable identification of patient and treatment risk factors for these toxicities and their impact on outcomes. PROCEDURE: We analyzed a retrospective pediatric ALL cohort treated at a single institution according to COG regimens from 2008 to 2015. The primary endpoint was cumulative incidence of study-defined "severe" hepatotoxicity (Common Terminology Criteria for Adverse Events [CTCAE] Grade ≥ 4 transaminitis or Grade ≥ 3 hyperbilirubinemia) and clinically significant pancreatitis (any grade). Pancreatitis was additionally classified using the Ponte di Legno (PdL) toxicity criteria. Secondary endpoints were chemotherapy interruptions, early disease response (end of induction [EOI] minimal residual disease [MRD]), and event-free survival (EFS). RESULTS: We identified 262 patients, of whom 71 (27%) and 28 (11%) developed hepatotoxicity and pancreatitis, respectively. Three cases of pancreatitis did not fulfill PdL criteria despite otherwise consistent presentations. Both TRTs occurred throughout therapy, but approximately 25% of hepatotoxicity (18/71) and pancreatitis (8/28) occurred during induction alone. Both obesity and age (≥10 years) were identified as predictors of hepatotoxicity (subdistribution hazard ratio [SHR] obesity = 1.75, 95% confidence interval [95% CI] 1.04-2.96; SHR age ≥10 = 1.9, 95% CI 1.19-3.10) and pancreatitis (SHR obesity = 2.18, 95% CI 1.01-4.67; SHR age ≥ 10 = 2.76, 95% CI 1.19-6.39, P = 0.018). Dose interruptions were common but neither toxicity influenced EOI MRD nor EFS. CONCLUSIONS: Obese and/or older children are particularly at risk for hepatotoxicity and pancreatitis, and may benefit from toxicity surveillance and chemoprotective strategies to prevent or mitigate associated morbidity.