A Treatment Study Protocol for Participants 0-45 Years With Acute Lymphoblastic Leukaemia

ALLTogether1 - A Treatment Study Protocol of the ALLTogether Consortium for Children and Young Adults (0-45 Years of Age) With Newly Diagnosed Acute Lymphoblastic Leukaemia (ALL)

The Swedish Research Council, The Swedish Childhood Cancer Foundation, Pfizer, Servier, NordForsk, Aamu Pediatric Cancer Foundation, German Society for Pediatric Oncology and Hematology GPOH gGmbH, Clinical Trial Center North (CTC North GmbH & Co. KG), Belgium Health Care Knowledge Centre, Karolinska Institutet, Cancer Research UK, Fundação Rui Osório de Castro, Acreditar - Associação de Pais e Amigos das Crianças com Cancro, Grupo Português De Leucemias Pediátricas, Amgen, Nova Laboratories Limited, Danish Child Cancer Foundation, Danish Cancer Society, The Novo Nordic Foundation, Assistance Publique - Hôpitaux de Paris, Direction Générale de l'Offre de Soins

ALLTogether collects the experience of previously successful treatment of infants, children and young adults, with ALL from a number of well-renowned study groups into a new master protocol, which is both a comprehensive system for stratification and treatment of ALL in this age-group as well as the basis for several randomised and interventional trials included in the study-design.

ALLTogether is a European clinical treatment study for acute lymphoblastic leukaemia (ALL) in infants, children and young adults. The aims are to improve survival and quality of survival. In young people, ALL has excellent outcome with an overall survival of about 92% in children and 75% in young adults. Infants with BCP-ALL and KMT2A-rearrangements have a worse outcome and are treated according to separate protocols, but infants with KMT2A-germline and T-cell ALL have acceptable outcome on standard ALL therapy. However, patients still die of disease - from relapse because of under-treatment and a large fraction of patients are also over-treated: All patients risk treatment-related death and some suffer long-term side-effects or secondary cancer. To show improvement with such good survival, large populations are needed. Study groups from Sweden, Norway, Iceland, Denmark, Finland, Estonia and Lithuania (NOPHO), the UK (UKALL), the Netherlands (DCOG), Germany (COALL), Belgium (BSPHO), Portugal (SHOP), Ireland (PHOAI), and France (SFCE), have designed a common treatment protocol. The study has a complex clinical trial design with sub-protocols (the randomisations / intervention) connected to a master protocol. The master protocol consists of well established therapy-elements and in its design typical for current ALL therapy. The master protocol therapy is in the study design considered as standard of care (SOC) therapy for infants, children and young adults with ALL. The study structure is defined by a master protocol onto which randomised and interventional sub-protocols as well as sub-studies may be added, run and stop in a modular fashion. The randomisations / intervention may identify therapy that is less toxic, but equally efficacious for sub-groups of patients and innovative therapy that may reduce relapses and death from ALL. In the master protocol, improved risk-stratification is likely to increase survival and reduce unnecessary toxicity and the introduction of therapeutic drug monitoring (TDM) of Asparaginase activity will make the use of Asparaginase more rational and efficient and may thus improve overall outcomes. The investigators hypothesise that patients stratified to the standard-risk group are over-treated. Therefore, it will be tested if the treatment can be safely reduced. In the R1 randomisation, patients will be randomised to receiving the Delayed Intensification (DI) phase of therapy with or without the anthracycline Doxorubicin. A similar hypothesis of over-treatment will also be tested in patients stratified to the intermediate risk-low group. In the R2 randomisation patients will be randomly assigned to either removal of Doxorubicin during the DI phase or removal of Vincristine and Dexamethasone pulses during the maintenance phase or to the control group, which will be treated with Doxorubicin in DI as well as Vincristine and Dexamethasone pulses during maintenance. Patients will only be randomised once. Randomisation R1 and R2 are only considered for children since adults have worse outcome and very poor survival after relapse, but the risk-stratification is likely to reduce the number of high-risk cases also in the adult-group. Patients stratified as intermediate risk-high (IR-high) are identified as having an increased risk of relapse and thus a less favourable prognosis than the standard- and intermediate risk-low groups, but a more favourable prognosis than the high risk patients. The majority of all relapses in childhood ALL is expected to occur in the IR-high group. Following a relapse, only approximately 40% of the children can be successfully treated again and for adults the corresponding figure is less than 20 %, so preventing relapses is very important. New treatment options that improves the antileukaemic efficacy and which have an improved safety profile are urgently needed. For IR-high patients Randomisation 3 (R3) is available. In R3 patients will be randomised to receive either: the addition of two cycles of Inotuzumab ozogamicin (InO) - Besponsa®, before start of the maintenance phase. After these cycles, the patients randomised to the InO arm will receive maintenance for the same duration as in the control arm. the addition of low dose 6-tioguanine (6TG) as an addition to the standard maintenance therapy. standard maintenance therapy Patients with ABL-class fusions in their leukaemic clone will, as a non-randomised experimental intervention, be treated with an addition of a tyrosine-kinase inhibitor during the induction phase (for patients <25 years) and from the consolidation phase (patients ≥25 years). This intervention may shift therapy for previously resistant cases to lower intensity treatment with the associated reduced morbidity and may also reduce the number of relapses in analogy with the results in Ph+ ALL. The reason for not performing a randomised comparison is the rarity of the aberration and also the diversity of ABL-class fusions, reducing statistical power for any comparison further. For this reason, the results of this intervention may be pooled with other study-groups trying similar approaches. A new intervention is introduced for Down syndrome patients with CD19 positive ALL: ALLTogether1 DS (NRI2). For Down syndrome-ALL patients who have end of Induction MRD detectable but <25% two conventional chemotherapy consolidation blocks will be replaced with two blocks of Blinatumomab. For high-risk B-lineage patients, CAR-T therapy can be an alternative to high-risk blocks and stem-cell transplant, but in this case the intervention (CAR-T infusion) will be performed outside the ALLTogether1 study. However, the stratification-system in ALLTogether1 will define the population with a potential CAR-T indication. ALLTogether1 also includes five sub-studies: Efficacy and pharmacokinetics of Imatinib in ABL-class fusion positive ALL Target population: All ABL-class patients enrolled in the ALLTogether study. Biomaterials to be collected at diagnosis, during TKI treatment, follow-up and relapse. Aims To determine the efficacy and dosing target of imatinib in the treatment of ABL-class leukemia To find the best discriminative biomarkers for TKI response in ABL-class ALL To determine the frequency of intrinsic (at diagnosis) and acquired TKI resistance (due to treatment), including backtracking of mutations using imatinib PK/PD findings during treatment To find causes of TKI resistance in ABL-class patients To describe the pharmacokinetics of Imatinib in TKI-treated patients Objectives To determine the percent of ABL-class patients who need to switch from IR-high to HR because of high MRD levels To determine the effect of imatinib exposure on clinical outcome, including pharmacokinetic measurements of imatinib To determine the molecular response to imatinib by monitoring fusion gene levels and mutational spectrum at diagnosis and during follow up To determine whether the molecular response parameters reflect the Ig/TCR MRD or flow-MRD response or are a better predictor of therapy failure than Ig/TCR or flow-based MRD monitoring To determine the phosphorylation status of ABL-class proteins and presence of TKI-resistance associated mutations in ABL genes prior to imatinib treatment and the emergence of such mutations during treatment with imatinib To determine the presence of mutations in regulatory /other genes before and during imatinib treatment and functionally address the importance of these mutations in TKI resistance To determine whether the efficacy of TKIs depends on the type of fusion gene To describe inter- and intraindividual variations in imatinib PK (=trough levels) during therapy of ABL-class ALL To describe associations between PK of imatinib and end-of-induction MRD (<25 yrs only) and end-of-consolidation MRD (all patients) To describe associations between imatinib PK and relapse rates (overall, bone-marrow and CNS), event-free survival as well as overall survival; To describe associations between imatinib PK and toxicities (including e.g. height z-scores at diagnosis and end of therapy, pancreatitis, treatment delays) with focus on those toxicities that are routinely monitored in ALLTogether. Biomarkers to Reform Approaches to therapy-Induced Neurotoxicity (BRAIN) Target population: All patients registered on ALLTogether1 aged ≥ 4 years at end of therapy (Arm A) and all patients registered on ALLTogether1 aged 4-21 years at start of therapy (Arm B) and without: Pre-existing neurodevelopmental delay (e.g Trisomy 21) prior to diagnosis of ALL Significant visual or motor impairment preventing use of a touch screen ipad All centres are invited to enrol to arm A (Main BRAIN) of the study. Arm B (Longitudinal BRAIN) will be carried out in selected centres. Aims To implement universal screening of all children for adverse neurocognitive outcomes at the end of treatment using a validated user-friendly computer software programme (CogState) and compare neurocognitive outcomes by treatment allocation (Arm A). To identify risk factors for adverse outcomes including whether acute neurotoxic events are associated with poor performance on cognitive tests at end of therapy compared to patients without acute neurotoxicity (Arm A). To examine changes in neurocognitive performance over time and the risk/protective factors associated with differences in outcome, such as demographic, clinical, and physical/psychosocial factors (Arm B). Primary end-point a. Proportion of children with a z-score <1.5 on detection and/or identification CogState tasks in each treatment arm at the end of ALL therapy. A z-score < 1.5 correlates with moderate cognitive impairment at a level that may require additional support. Secondary and exploratory end-points Association between CogState scores at end of treatment and overt neurotoxic episodes as recorded on the trial adverse event database. Association between Cogstate scores and clinical and demographic variables - age, sex, ethnicity, CNS status. Proportion of children with scores <1.5SD for one card learning (learning), one back (working memory) and Groton's maze (executive function) on different treatment arms. Association between CogState scores and patient reported outcome measures/Quality of life measurements collected as part of the main ALLTogether1 trial. Changes in neurocognitive scores over time, including CogState and BRIEF-2/BRIEF-A scores. Association between neurocognitive scores over time and interactions with demographic variables (age, sex), clinical variables (treatment arm, neurotoxicity), social-emotional and physical functioning (SDQ, PedsQL 4.0 Generic; PedsQL 3.0 Fatigue), and family factors (MEES; PedsQL FIM) Association between asparaginase activity levels and outcome Target population: All patients included in the ALLTogether1 protocol are eligible for participation. Primary aim To study the association between asparaginase activity levels and outcome (MRD, relapse, survival) Secondary aims To evaluate the association between asparaginase activity levels and toxicities, such as pancreatitis, infections and deep venous thrombosis (DVT) To evaluate the association between asparaginase activity levels and hepatotoxicity in a subset of patients CSF-Flow Target population: All patients included in the ALLTogether1 protocol are eligible for participation Aims To use cerebrospinal fluid (CSF) flow cytometry (FCM) to improve the accuracy of diagnostic tests for CNS leukaemia compared to conventional CSF cytology. An associated objective will be to develop a recommended protocol for CSF flow cytometry with external quality assessment to ensure uniformity of measurement across the ALLTogether consortium. To investigate whether negative FCM identifies a group of children at very low risk of CNS relapse, suitable for testing de-escalation of CNS-directed therapy in future trials. To investigate whether positive FCM can identify children at increased risk of CNS relapse and whether patients with persistent positivity (FCM positive at day 15 onwards) might benefit from studies testing escalated CNS-directed therapy or a switch to more intensive treatment arms. To collect matching CSF supernatant for studies comparing CSF FCM with soluble biomarkers (e.g. metabolic, cell-free DNA, proteomic and microRNA). Maintenance therapy pharmacokinetics/-dynamics study Target population: All patients included in the ALLTogether1 protocol are eligible for participation. For IR-high patients participating in the randomised InO- and TEAM sub-protocols, the monitoring of 6-mercaptopurine (6MP)/Methotrexate (MTX) metabolites at three months intervals is mandatory. Aims and specific objectives To map pharmacokinetics of 6MP and MTX during maintenance therapy in all patients in the ALLTogether protocol. To associate metabolite profiles with TPMT and NUDT15 variants, as routinely analysed in ALLTogether. To explore the association of event-free survival with DNA-TG and other 6MP/MTX metabolites. To explore the association between risk of second cancers with DNA-TG and other 6MP/MTX metabolites. To explore the association of risk of invasive infections with DNA-TG and other 6MP/MTX metabolites. To explore the association of risk of osteonecrosis with DNA-TG and other 6MP/MTX metabolites. To explore the association of sinusoidal obstruction syndrome with DNA-TG and other 6MP/MTX metabolites.

Leukemia, Acute Leukemia, ALL, ALLTogether, Leukaemia, Inotuzumab ozogamicin, Besponsa, ALLTogether1, Blinatumomab, Blincyto, 6-tioguanine, 6-thioguanine

Master protocol with risk-stratification. The risk-stratified groups will proceed to non-randomised or randomised interventions in single arm (TKI) and (Blinatumomab) and parallel (R1/R2/R3) models respectively.

Standard treatment with Delayed Intensification including Doxorubicin and Maintenance including Vincristine+Dexamethasone pulses.

Standard treatment with omission of Doxorubicin IV 3 x 30 mg/m2/dose in the Delayed Intensification phase.

Inotuzumab IV 0,5 mg/m2, given on days 253, 260, 267 and on days 274, 281, 288 before start of Standard Maintenance Therapy.

Imatinib p.o. 340 mg/m2 given daily from day 15 or 30 (depending on age) to the end of therapy (week 106) in addition to Standard IR-high chemotherapy.

Blinatumomab IV, 5 mcg/m2/day up to 28 mcg/day (detailed dosing in protocol) continous infusion. Two 28 day courses with a two week treatment free interval in between. Blinatumomab courses replace Consolidation 1 and Consolidation 2 in the standard protocol adapted for Down syndrome patients.

Standard treatment with omission of monthly pulses of Vincristine IV 1,5 mg/m2/dose and 5 days of Dexamethasone p.o. 6 mg/m2/day in the Maintenance Phase.

The primary endpoint for the whole protocol (compared with the legacy protocols of the participating study-groups forming the consortium) is event-free survival (EFS) - as defined in the protocol.

5 year estimates from the time of diagnosis will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

The primary endpoint for the TKI intervention is event-free survival (EFS) - as defined in the protocol, from the start of TKI until event or end of follow-up

From the start of TKI (day 15 or day 30), 5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up for all interventions except Inotuzumab-randomisation (minimum 2-year follow-up).

The primary endpoint for Randomisation 1 and 2 is disease-free survival (DFS) - as defined in the protocol counting from the time of randomisation

5 and 8 year estimates from the time of randomisation will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

The primary endpoint for Randomisation 3 and the ABL-class fusion intervention is disease-free survival (DFS) - as defined in the protocol counting from the time of randomisation (R3) and the start of TKI-therapy (ABL-class fusion intervention).

5 year estimates from the time of randomisation will be measured but adequate follow-up for these estimates will be ensured: at least 2-year follow-up

Fraction of patients with undetectable MRD ("Complete MRD response") at the end of one cycle of Blinatumomab (+/- 1 week)

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Overall survival defined as time from randomisation to death or end of follow-up for surviving patients.

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Overall survival defined as time from randomisation to death or end of follow-up for surviving patients.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Overall survival defined as time from start of TKI to death or end of follow-up for surviving patients

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up (TKI).

Overall survival defined as time from start of Blinatumomab to death or end of follow-up for surviving patients

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Fraction of patients who die as well as cumulative incidence of death before achieved complete remission (CR) within the time-frame described in the protocol

From diagnosis until death before remission (at the earliest, day 29) or in case of no CR day 29, completion of induction and consolidation 1 (protocol day 99 - Down) and in addition 3 high-risk blocks (protocol day 134 - all other patients)

Fraction of patients as well as cumulative incidence of resistant disease as described in the protocol. Induction death as competing risk.

From diagnosis until achieved complete remission (at the earliest, day 29) or in case of no CR day 29, assessment after induction and consolidation 1 (protocol day 99-Down patients) and in addition 3 high-risk blocks (protocol day 134-all other patients)

Time from achieved complete remission until relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission as competing events.

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Cumulative incidence of relapse as defined for R3 in association with DNA-TG for R3-TEAM. Second malignancy, death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Time from randomisation until relapse without expression of CD22 as defined in the protocol or end of follow-up. Second malignancy, death in complete remission and relapse with CD22 expression as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Time from start of TKI until relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Time from start of Blinatumomab until relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Time from start of Blinatumomab until CD19 negative relapse as defined in the protocol or end of follow-up. Second malignancy, death in complete remission and CD19 positive relapse as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Time from achieved complete remission until diagnosis of second malignant neoplasm as defined in the protocol or end of follow-up. Relapse and death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until diagnosis of second malignant neoplasm as defined in the protocol or end of follow-up. Relapse and death in complete remission as competing events.

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until diagnosis of second malignant neoplasm as defined in the protocol or end of follow-up. Relapse and death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up.

Cumulative incidence of second malignancy as defined above for R3 in association with DNA-TG for R3-TEAM. Relapse and death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up.

Time from start of TKI until diagnosis of second malignant neoplasm as defined in the protocol or end of follow-up. Relapse and death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from start of Blinatumomab until diagnosis of second malignant neoplasm as defined in the protocol or end of follow-up. Relapse and death in complete remission as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from achieved complete remission until death in complete remission as defined in the protocol or end of follow-up. Relapse and second malignant neoplasm as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until death in complete remission as defined in the protocol or end of follow-up. Relapse and second malignant neoplasm as competing events.

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up.

Time from randomisation until death in complete remission as defined in the protocol or end of follow-up. Relapse and second malignant neoplasm as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Time from start of TKI until death in complete remission as defined in the protocol or end of follow-up. Relapse and second malignant neoplasm as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Time from start of Blinatumomab until death in complete remission as defined in the protocol or end of follow-up. Relapse and second malignant neoplasm as competing events.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Time from diagnosis until death during induction, death in complete remission or death from second malignant neoplasm (if not related to SMN-treatment).

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

Time from randomisation until death in complete remission or death from second malignant neoplasm (if not related to SMN-treatment).

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up.

Time from randomisation until death in complete remission or death from second malignant neoplasm (if not related to SMN-treatment).

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

Time from start of TKI until death in complete remission or death from second malignant neoplasm (if not related to SMN-treatment).

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

5 and 8 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up.

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 2 years follow-up

5 year estimates will be measured but adequate follow-up for these estimates will be ensured: at least 5 years follow-up

Incidence of Adverse Events of Special Interest (AESIs) per treatment-phase in the whole protocol and TKI intervention

From time of diagnosis after each treatment-phase (one extra in the middle of maintenance) and annually until 5 years from discontinuation of therapy.

Cumulative incidence of AESIs estimated 3 months after start of maintenance (R1+R2) and at the end of maintenance (R2)

From time of randomisation until the end of maintenance therapy (approximately 77 weeks from randomisation)

From time of randomisation, assessment after delayed intensification and 6 weeks after start of maintenance

At the end of therapy (approximately 94 weeks from randomisation) and 5 years after discontinuation of treatment

5 year estimates from the time of randomisation will be measured but adequate follow-up for these estimates will be ensured: at least 2-year follow-up

Cumulative incidence of Sinusoidal Obstruction Syndrome (SOS) and Nodular Regenerative Hyperplasia (NRH) for R3-TEAM

Time from randomisation until diagnosis of SOS or NRH as defined in the protocol or end of follow-up.

Time from randomisation until diagnosis of osteonecrosis as defined in the protocol or end of follow-up.

Event-free survival as defined in the protocol, from the start of Blinatumomab until death from any cause, relapse, second malignancy, protocol therapy failure (MRD>1% after 2 cycles blinatumomab and Augmented BFM consolidation) or end of follow-up.

From the start of Blinatumomab, 5 year estimate will be measured but adequate follow-up for this estimate will be ensured: at least 5 years follow-up.

Incidence of progressive disease under Blinatumomab treatment or MRD ≥1% at the end of the 2nd cycle of Blinatumomab.

From the start of Blinatumomab until end of 2nd cycle of Blinatumomab (each cycle is 4 weeks followed by a 2-week treatment free period)

Incidence of patients who have MRD ≥1 % post 2 cycles of Blinatumomab followed by Augmented BFM consolidation, corresponding to original protocol day 99, or unchanged/increasing MRD during Augmented BFM consolidation corresponding to original protocol day 57.

From the start of Blinatumomab until the end of Consolidation 1 (85-140 days: 15-70 days of Blinatumomab therapy + 70 days of Consolidation 1)

From start of Maintenance therapy until the end of Maintenance therapy (protocol week 38 until protocol week 108)

From start of Maintenance therapy until the end of Maintenance therapy (protocol week 38 until protocol week 108)

Inclusion Criteria: Patients newly diagnosed with T-lymphoblastic (T-cell) or B-lymphoblastic precursor (BCP) leukaemia (ALL) according to the WHO-classification of Tumours of Haematopoetic and Lymphoid Tissues (Revised 4th edition 2017) and with a diagnosis confirmed by an accredited laboratory at a participating paediatric oncology or adult haematology centre. Age 0 - < 46 years (one day before 46th birthday) at the time of diagnosis with the exception of infants with KMT2A-rearranged (KMT2A-r) BCP ALL. Patients with surface immunoglobulin negative (sIG-) BCP-ALL and an IG::MYC rearrangement, unless they have a concurrent BCL2/6 rearrangement. T-ALL patients with MYC translocations. Informed consent signed by the patient and/or parents/legal guardians according to country-specific age-related guidelines. The ALL diagnosis should be confirmed by an accredited laboratory at a participating paediatric oncology or adult haematology centre. The patient should be diagnosed and treated at a participating paediatric oncology or adult haematology centre in the participating countries. The patient should be a resident in one of the participating countries on a permanent basis or should intend to settle in a participating country, for instance by an application for asylum. Patients who are visiting the country as tourists should not be included. However, returning expatriots with primary diagnosis abroad may be included if no treatment has been administered and the diagnostic procedures are repeated at a participating centre. All women of childbearing potential (WOCBP) have to have a negative pregnancy test within 2 weeks prior to the start of treatment. For each intervention/randomisation an additional set of inclusion-criteria is provided. Exclusion Criteria: Age < 365 days and KMT2A-rearranged (KMT2A-r) BCP-ALL (documented presence of a KMT2A-split by FISH and/or a KMT2A fusion transcript). Age >45 years at diagnosis. Patients with a previous malignant diagnosis (ALL as a second malignant neoplasm - SMN). Relapse of ALL. Patients with mature B-ALL (as defined by surface IG positivity) or any patients with IG::MYC and a concurrent BCL2/6 rearrangement. Patients with Ph-positive ALL (documented presence of t(9;22)(q34;q11) and/or of the BCR::ABL fusion transcript). These patients will be transferred to an appropriate trial for t(9;22) if available. Previously known ALL prone syndromes (e.g. Li-Fraumeni syndrome, germline ETV6 mutation), except for Down syndrome. Exploration for such ALL prone syndromes is not mandatory and patients in whom genetic work-up reveals a new germ-line mutation (index-cases) will remain in the study. Treatment with systemic corticosteroids (>10mg/m2/day) for more than one week and/or other chemotherapeutic agents in a 4-week interval prior to diagnosis (pre-treatment). Pre-existing contraindications to any treatment according to the ALLTogether protocol (constitutional or acquired disease prior to the diagnosis of ALL preventing adequate treatment). Any other disease or condition, as determined by the investigator, which could interfere with the participation in the study according to the study protocol, or with the ability of the patients to cooperate and comply with the study procedures. Women of childbearing potential who are pregnant at the time of diagnosis. Women of childbearing potential and fertile men who are sexually active and are unwilling to use adequate contraception during therapy. Efficient birth control is required. Female patients, who are breast-feeding. Essential data missing from the registration of characteristics at diagnosis (in consultation with the protocol chair). For each intervention/randomisation an additional set of exclusion-criteria is provided.

ALLTogether Data Sharing Policy FINAL VERSION 1.0 DATED 12APRIL2022 applies (full details available from Trial Central Office): Policy The ALLTogether Consortium aims to maximise the availability of research data to the academic community for academic non-commercial research purposes with as few restrictions as possible. All research papers should be open access whenever possible. Clinical data: The ALLTogether Consortium will consider requests for individual participant data (IPD) that underlie published results after deidentification. Requests for access for unpublished data will also be considered on a case-by-case basis. ALLTogether scientific data underpinning basic science/translational research papers should be made available to other researchers in the ALLTogether consortium and requests from academic researchers outside the consortium for access to scientific datasets should be addressed to the lead investigator of the ALLTogether study.

The ALLTogether Consortium will consider requests for individual participant data (IPD) that underlie published results after deidentification. Requests for access for unpublished data will also be considered on a case-by-case basis.

Data access requests will be reviewed by The ALLTogether Board and, when applicable the ALLTogether Scientific committee. IPD will only be released if all personalised identifiers can be removed and for the sole use of the approved request (tertiary dissemination will not be permitted). Requestors will be required to sign a Data Access Agreement.

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