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Standard testing for disease evaluation in B-cell acute lymphoblastic leukemia (B-ALL) includes examination of the bone marrow and cerebrospinal fluid. Radiographic or functional imaging are indicated when clinical signs of non-CNS extramedullary disease are present but are not standard in the relapsed/refractory setting. We describe two cases of patients with relapsed/refractory BALL with prior exposure to blinatumomab and/or inotuzumab ozogamicin presenting for CAR-T cell treatment. Both patients were thought to only have minimal residual disease (MRD) at the pre-CAR disease assessment, with MRD of 6,648 (0.66%) and 100 (0.01%) cells per million cells, respectively, as measured by next-generation sequencing (NGS) in their bone marrows. Both patients for distinct reasons unrelated to non-CNS extra-medullary (EM) symptoms had PETMRIs prior to lymphodepletion and CAR T cell infusion. In both cases patients were found to have significant bulky subclinical EM disease that required changes in clinical management. In the newly-emergent era of antigen-targeted immunotherapy, it is foundational that incidence and relapse patterns following targeted therapy are well-understood. Herein we contribute to a growing body of literature addressing this fundamental clinical gap and highlight a future role for formal prospective imaging studies to better establish response, toxicity and relapse patterns following CAR-T cell therapy in EM B-ALL. [ABSTRACT FROM AUTHOR]

With advancements in novel therapeutics, it is unclear whether third hematopoietic cell transplantation (HCT3) has a place in the treatment of recurrent hematopoietic malignancies. We evaluated patients with hematologic malignancies who underwent HCT3 between 2000–2020. Nine patients, with a median age of 18 (9—68) years at HCT3 with acute myelogenous leukemia (n = 5), acute lymphoblastic leukemia (n = 2), myelodysplastic syndrome (n = 1), or undifferentiated acute leukemia (n = 1), were identified. The median time between first HCT and HCT3 was 3.9 (0.7—13.6) years. Indication for HCT3 was relapse (n = 8) or graft failure (n = 1) after second HCT. At HCT3, seven of nine patients were in complete remission by flow cytometry. All experienced robust donor engraftment by one month after HCT3 (≥ 90% CD3) while one died at day + 24 of multi-organ failure and was not evaluable for chimerism. In total, eight patients died from relapse (n = 4), non-relapse, (n = 3) or unknown (n = 1) causes at a median of 0.6 (range, 0.1 – 9.9) years after HCT3. After HCT3, estimated overall survival at 6 months, 1 year, and 5 years was 88%, 63%, and 22%, respectively. In this highly selected group, HCT3 provided a treatment option although long-term survival was still dismal. [ABSTRACT FROM AUTHOR]

Standard testing for disease evaluation in B-cell acute lymphoblastic leukemia (B-ALL) includes examination of the bone marrow and cerebrospinal fluid. Radiographic or functional imaging are indicated when clinical signs of non-CNS extramedullary disease are present but are not standard in the relapsed/refractory setting. We describe two cases of patients with relapsed/refractory B-ALL with prior exposure to blinatumomab and/or inotuzumab ozogamicin presenting for CAR-T cell treatment. Both patients were thought to only have minimal residual disease (MRD) at the pre-CAR disease assessment, with MRD of 6,648 (0.66%) and 100 (0.01%) cells per million cells, respectively, as measured by next-generation sequencing (NGS) in their bone marrows. Both patients for distinct reasons unrelated to non-CNS extra-medullary (EM) symptoms had PET-MRIs prior to lymphodepletion and CAR T cell infusion. In both cases patients were found to have significant bulky subclinical EM disease that required changes in clinical management. In the newly-emergent era of antigen-targeted immunotherapy, it is foundational that incidence and relapse patterns following targeted therapy are well-understood. Herein we contribute to a growing body of literature addressing this fundamental clinical gap and highlight a future role for formal prospective imaging studies to better establish response, toxicity and relapse patterns following CAR-T cell therapy in EM B-ALL.

Although improved survival in children with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL) has been demonstrated in trials, the outcome appears to be inferior in low- and middle-income countries (LMIC). Methods A file review of children aged ≤ 15 years diagnosed with Ph-ALL from 2010 to 2019 was performed. Minimal residual disease (MRD) was assessed by flow-cytometry. Real-time polymerase chain reaction (qRT-PCR) was used to quantify the BCR::ABL1 transcripts during treatment. Results The mean age of the 20 patients in the study was 91 months. Of 19 patients in whom the BCR::ABL1 transcript was confirmed, 10(50%) had P210, 7(35%) had P190, and two showed dual expression. The mean dose of imatinib that was administered was 294 ± 41 mg/m2/day. qRT-PCR for BCR::ABL1 was < 0.01% in all patients who were in remission or had a late relapse and was ≥ 0.01% in patients who had an early relapse. Two patients underwent HSCT. The 3-year event-free survival (EFS) was 35.0 ± 10.7%. Patients with a good prednisolone response (GPR) and a negative end-of-induction MRD demonstrated a superior EFS to those who lacked either or both (80.0 ± 17.9% vs. 16.7 ± 15.2%, P = 0.034). Conclusion The 3-year EFS of 20 children with Ph-ALL treated with chemotherapy and TKI was < 50%. An unusually high proportion of patients with p210 transcript expression; sub-optimal TKI dosing and lesser intensity of chemotherapy, due to the concern of high treatment-related mortality in LMIC are possible reasons for the poor outcome. Conventional treatment response parameters such as GPR and MRD predict outcomes in Ph-ALL. qRT-PCR for BCR::ABL1 may have a role in predicting early relapse. [ABSTRACT FROM AUTHOR]

Acute Lymphoblastic Leukemia is a very aggressive malignant disorder of lymphoid cells in adults, with recurrence (30 to 60% of the cases) after the initial treatment. Until this moment, there is no gold standard therapy for the treatment of adult patients with acute relapsed/refractory lymphoblastic leukemia. In this case report, we describe two cases of relapsed leukemia: one of lymphocytic leukemia B and one of trilineage leukemia, which presented a satisfactory response to treatment with Bortezomib associated with Vincristine, Dexamethasone, and Bendamustine.

Acute Lymphoblastic Leukemia is a very aggressive malignant disorder of lymphoid cells in adults, with recurrence (30 to 60% of the cases) after the initial treatment. Until this moment, there is no gold standard therapy for the treatment of adult patients with acute relapsed/refractory lymphoblastic leukemia. In this case report, we describe two cases of relapsed leukemia: one of lymphocytic leukemia B and one of trilineage leukemia, which presented a satisfactory response to treatment with Bortezomib associated with Vincristine, Dexamethasone, and Bendamustine. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T cell therapy has been used as a targeted approach in cancer therapy. Relapsed and refractory acute leukemia in pediatrics has been difficult to treat with conventional therapy due to dose limiting toxicities. With the recent success of CD 19 CAR in pediatric patients with B cell ALL, this mode of therapy has become a very attractive option for these patients with high risk disease. In this review, we will discuss current treatment paradigms of pediatric acute leukemia, and potential therapeutic targets for additional high risk populations, including T cell ALL, AML, and infant ALL.

Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathway-activating mutations in the neuroblastoma RAS viral oncogene homolog (NRAS), kirsten rat sarcoma viral oncogene homolog (KRAS), and protein tyrosine phosphatase, nonreceptor type 11 (PTPN11) genes were present in 24 of 55 (44%) cases in our series. Interestingly, some leukemias showed retention or emergence of RAS mutant clones at relapse, whereas in others RAS mutant clones present at diagnosis were replaced by RAS wildtype populations, supporting a role for both positive and negative selection evolutionary pressures in clonal evolution of RAS-mutant leukemia. Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts. These results highlight the central role of chemotherapy-driven selection as a central mechanism of leukemia clonal evolution in relapsed ALL, and demonstrate a previously unrecognized dual role of RAS mutations as drivers of both sensitivity and resistance to chemotherapy. [ABSTRACT FROM AUTHOR]

Abstract: Receptor activated tyrosine kinases such as c-kit, c-fms and PDGFR are known targets of inhibition by imatinib mesylate (Gleevec) and are expressed on AML blasts. Marrow stromal cells and monocytes express KIT ligand, M-CSF and PDGF and are therefore capable of activating survival pathways in these leukemic cells. Given the synergy in vitro between Ara-C and imatinib mesylate on AML cell growth inhibition, we initiated a Phase I study combining CLAG+imatinib mesylate in AML patients. Patients with relapsed, refractory AML or CML myeloid blast crisis were eligible to receive Cladribine 5mg/m2 days 3–7, Cytarabine 2gm/m2 days 3–7, G-CSF 300mcg days 2–7, and escalating doses of imatinib mesylate given on days 1–15. The level 1 Gleevec dose was 400mg, while level 2 was 600mg and the level 3 dose 800mg. A total of 16 patients were enrolled, 15 AML and 1 CML myeloid blast crisis. The dose escalation occurred as planned and there was no clear evidence of added toxicity due to imatinib mesylate. One patient with an extensive cardiac history died of cardiac causes on day 1 of therapy however no other deaths occurred within 30 days of starting therapy. One patient had a Grade 3 skin rash at dose level 2. The most common toxicities encountered during induction therapy were nausea, vomiting, rash and diarrhea that were transient and/or reversible. At the 800mg dose 1 patient developed a decline in cardiac ejection fraction on day 20 who later died of sepsis, so this was considered a dose limiting toxicity. Of 16 evaluable patients 11 achieved a hypocellular marrow after initial induction with 1 additional patient achieving a hypocellular marrow following a second course of the same regimen. Four patients (25%) achieved a complete morphologic response with normal cytogenetics, 2 patients (12.5%) achieved a complete morphologic response only and 1 patient had a complete response in the bone marrow but incomplete blood count recovery. The overall response rate was 43.8%. The median overall survival was 175 days (95% CI 16.24–333.76) and the median relapse free survival was 76 days. The addition of imatinib mesylate to CLAG was well tolerated with acceptable toxicities and response rates comparable to other salvage regimens. To assess the efficacy of imatinib mesylate in combination with CLAG, a larger phase II trial is now planned. [Copyright &y& Elsevier]

A marked improvement in the outcome of patients with acute lymphoblastic leukemia has been achieved with chemotherapeutic agents developed between the 1950s and 1970s. As the limits of optimizing the use of old drugs are reached, most adults with acute lymphoblastic leukemia still succumb to their disease and leukemia remains the leading cause of nonaccidental death in children. Salvage regimens, based mostly on different combinations of the same agents used in front-line therapy, carry a high incidence of morbidity and dismal long-term survival rates. New therapeutic strategies are needed. Clofarabine, a next-generation deoxyadenosine analog, has demonstrated significant activity in children and adults with refractory lymphoid and myeloid leukemia in early clinical trials and was granted approval for use in children with acute lymphoblastic leukemia in second or higher relapse. This is the only anticancer drug to receive primary indication for use in children over the past decade. Ongoing studies are exploring the benefit of clofarabine combinations in less heavily pretreated patients and the use of different dose schedules in a variety of hematological malignancies. [ABSTRACT FROM AUTHOR]

This paper discusses background informationand the body of clinical data that has beenaccumulated to demonstrate the efficacy andsafety of gemtuzumab ozogamicin (Mylotarg®Wyeth Pharmaceuticals, Philadelphia, PA).Based on these data, gemtuzumab ozogamicinwas approved by the United States Food andDrug Administration for the treatment ofpatients with CD33-positive acute myeloidleukemia in first relapse who are 60 yearsof age or older and who are not consideredcandidates for other cytotoxicchemotherapy. The recommended dosage ofgemtuzumab ozogamicin is 9 mg/m2,administered as a 2-hour intravenousinfusion for a total of 2 doses with 14days between doses. [ABSTRACT FROM AUTHOR]

Resistant AML encompasses two groups of patients: those with refractory leukemia and those whose leukemia has relapsed. Refractory leukemia is disease that does not respond to initial induction chemotherapy with cytarabine and an anthracycline. Patients with refractory leukemia are likely to have disease with adverse cytogenetics, a history of antecedent hematologic disturbance, adverse immunophenotypic features, and expression of multiple drug resistance. On the other hand, relapsed leukemia is leukemia that recurs following a CR. The duration of CR greatly affects the patient's prognosis and response to additional treatment. Patients with relapsed leukemia are heterogeneous with variable pretreatment characteristics. [ABSTRACT FROM AUTHOR]

• We compared CLAG-M and MEC in relapsed and refractory AML. • Response rates were 61 % for CLAG-M and 56 % for MEC. • No significant differences in overall survival were seen between the 2 regimens. • Trends towards improved survival in those treated with MEC then ASCT were noted. • Superior survival may occur in patients with late relapse treated with MEC then ASCT. Salvage therapy regimens for refractory and relapsed AML include mitoxantrone, etoposide, and cytarabine (MEC) and cladribine, cytarabine, filgrastim, and mitoxantrone (CLAG-M). We analyzed patients receiving either CLAG-M or MEC as salvage therapy for RR-AML between 09/01/2009-12/31/2017. Of 150 patients with RR-AML, 34 patients received CLAG-M and 116 MEC. CR/CRi rates for CLAG-M and MEC were 61.3 % (19/31) and 55.6 % (60/108). Median OS was 9.5 months for CLAG-M and 10.0 months for MEC (HR = 0.88,95 %CI = 0.54–1.41,p = 0.59). 76 patients proceeded to ASCT following salvage therapy. Median OS after ASCT was 13.0 months for CLAG-M and 31.0 months for MEC (HR = 1.76,95 %CI = 0.87–3.56,p = 0.12). Among those with late relapse and ASCT, median OS was 9.0 and 48.0 months for CLAG-M and MEC, respectively (HR = 17.6,95 %CI = 1.57–198,p < 0.001). There were no significant differences in outcome between CLAG-M vs. MEC regardless of transplant status. There was a significant improvement in survival in patients with late relapse treated with MEC who proceeded to ASCT. [ABSTRACT FROM AUTHOR]

18 F-FDG PET / CT is used clinically for the detection of extramedullary lesions in patients with relapsed acute leukemia (AL). However, the visual analysis of 18 F-FDG diffuse bone marrow uptake in detecting bone marrow involvement (BMI) in routine clinical practice is still challenging. This study aims to improve the diagnostic performance of 18 F-FDG PET/CT in detecting BMI for patients with suspected relapsed AL. Methods : Forty-one patients (35 in training group and 6 in independent validation group) with suspected relapsed AL were retrospectively included in this study. All patients underwent both bone marrow biopsy (BMB) and 18 F-FDG PET/CT within one week. The BMB results were used as the gold standard or real "truth" for BMI. The bone marrow 18 F-FDG uptake was visually diagnosed as positive and negative by three nuclear medicine physicians. The skeletal volumes of interest were manually drawn on PET/CT images. A total of 781 PET and 1045 CT radiomic features were automatically extracted to provide a more comprehensive understanding of the embedded pattern. To select the most important and predictive features, an unsupervised consensus clustering method was first performed to analyze the feature correlations and then used to guide a random forest supervised machine learning model for feature importance analysis. Cross-validation and independent validation were conducted to justify the performance of our model. Results : The training group involved 16 BMB positive and 19 BMB negative patients. Based on the visual analysis of 18 F-FDG PET, 3 patients had focal uptake, 8 patients had normal uptake, and 24 patients had diffuse uptake. The sensitivity, specificity, and accuracy of visual analysis for BMI diagnosis were 62.5%, 73.7%, and 68.6%, respectively. With the cross-validation on the training group, the machine learning model correctly predicted 31 patients in BMI. The sensitivity, specificity, and accuracy of the machine learning model in BMI detection were 87.5%, 89.5%, and 88.6%, respectively, significantly higher than the ones in visual analysis ( P < 0.05). The evaluation on the independent validation group showed that the machine learning model could achieve 83.3% accuracy. Conclusions: 18 F-FDG PET/CT radiomic analysis with machine learning model provided a quantitative, objective and efficient mechanism for identifying BMI in the patients with suspected relapsed AL. It is suggested in particular for the diagnosis of BMI in the patients with 18 F-FDG diffuse uptake patterns., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Patients with haematological malignancy are often profoundly immune suppressed, and more so if they require more than one line of therapy. Infection should always be considered when they become unwell. We discuss the differential diagnoses of a young man with multiply-relapsed Philadelphia chromosome-positive B-cell acute lymphoblastic leukaemia who presented with neurological symptoms and cerebrospinal fluid lymphocytosis. The diagnostic approach needs to be rapid and structured, and may require microbiology and neurology support.

Introduction: No standard salvage chemotherapy regimen is available for relapsed or refractory (RR) acute myeloid leukemia (AML). Preclinical data have suggested synergy in vitro between cytarabine and imatinib mesylate (IM) on AML cell growth inhibition. After demonstrating the safety and feasibility in a phase I study, we conducted a phase II clinical study of CLAG (cladribine, cytarabine, granulocyte colony-stimulating factor) regimen combined with IM for patients with RR-AML., Patients and Methods: We performed a single-institution 2-stage phase II study. The primary endpoint was the remission rate measured using the standard AML response criteria. The secondary endpoints included overall survival (OS) and progression-free survival (PFS)., Results: From August 2009 to April 2011, 38 patients were treated at the Moffitt Cancer Center. Their median age was 62 years (range, 26-79 years). Of the 38 patients, 7 (18%) had refractory AML, 19 (50%) had early relapse, and 12 (32%) had late relapse. At the original diagnosis, only 2 patients had favorable risk factors, 18 had intermediate risk, and 16 had poor risk; for 2 patients, the karyotype was missing. The overall response rate for all 38 evaluable patients was 37%. The median OS was 11.1 months (95% CI, 4.8-13.4 months), the median PFS was 4.9 months (95% CI, 1.6-11.7 months). Among the responders, 8 of 14 patients subsequently underwent allogeneic hematopoietic cell transplantation., Conclusion: CLAG plus IM was well tolerated, with encouraging signs of activity in patients with poor-risk AML., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathway-activating mutations in the neuroblastoma RAS viral oncogene homolog (NRAS), kirsten rat sarcoma viral oncogene homolog (KRAS), and protein tyrosine phosphatase, nonreceptor type 11 (PTPN11) genes were present in 24 of 55 (44%) cases in our series. Interestingly, some leukemias showed retention or emergence of RAS mutant clones at relapse, whereas in others RAS mutant clones present at diagnosis were replaced by RAS wild-type populations, supporting a role for both positive and negative selection evolutionary pressures in clonal evolution of RAS-mutant leukemia. Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts. These results highlight the central role of chemotherapy-driven selection as a central mechanism of leukemia clonal evolution in relapsed ALL, and demonstrate a previously unrecognized dual role of RAS mutations as drivers of both sensitivity and resistance to chemotherapy., Competing Interests: The authors declare no conflict of interest.

Chimeric antigen receptor (CAR) T cell therapy has been used as a targeted approach in cancer therapy. Relapsed and refractory acute leukemia in pediatrics has been difficult to treat with conventional therapy due to dose-limiting toxicities. With the recent success of CD 19 CAR in pediatric patients with B cell acute lymphoblastic leukemia (ALL), this mode of therapy has become a very attractive option for these patients with high-risk disease. In this review, we will discuss current treatment paradigms of pediatric acute leukemia and potential therapeutic targets for additional high-risk populations, including T cell ALL, AML, and infant ALL.