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The expression of CD20 in precursor B-cell acute lymphoblastic leukemia (B-ALL) is associated with poor outcomes. The addition of rituximab to intensive chemotherapy in CD20+ ALL has led to improved outcomes in several studies. However, there is no clear evidence regarding the optimal number of doses and its benefit without an allogeneic stem cell transplant. Achieving measurable residual disease (MRD)-negative status postinduction would reduce the requirement for a transplant. Novel approaches are needed to induce a higher proportion of MRD-negative complete remission in patients with high-risk ALL. Given bortezomib’s activity in relapsed ALL and its synergism with rituximab in B-cell lymphomas, the addition of bortezomib to rituximab and chemotherapy may provide an incremental benefit in CD20+ precursor B-ALL. We conducted a phase 2 study to test the activity of bortezomib and rituximab in combination with a pediatric-inspired regimen during induction therapy in newly diagnosed adolescents and adults (aged >14 years) with CD20+, Philadelphia-negative precursor B-ALL; bone marrow MRD negativity at the end of induction was the primary end point. From December 2017 through August 2019, a total of 35 patients were enrolled. End-of-induction MRD-negative status was achieved in 70.9% of patients, as opposed to 51.7% in the historical cohort treated with chemotherapy alone. MRD-negative rates improved to 87.5% post-consolidation. At a median follow-up of 21 months, event-free survival and overall survival rates were 78.8% (95% confidence interval, 66-94) and 78.7% (95% confidence interval, 65.8-94), respectively. There was no significant increase in toxicity with bortezomib and rituximab compared with the historical cohort. The incidence of neuropathy was 26% (all less than grade 3). The combination of bortezomib, rituximab, and a pediatric-inspired ALL regimen was active and well tolerated in de novo CD20+ Philadelphia-negative precursor B-ALL. This trial was registered with the Clinical Trials Registry-India as CTRI/2017/04/008393(http://ctri.nic.in/Clinicaltrials).

We accrued 201 patients of adult AML treated with conventional therapy, in morphological remission, and evaluated MRD using sensitive error-corrected next generation sequencing (NGS-MRD) and multiparameter flow cytometry (FCM-MRD) at the end of induction (PI) and consolidation (PC). Nearly 71% of patients were PI NGS-MRD+ and 40.9% PC NGS-MRD+ (median VAF 0.76%). NGS-MRD+ patients had a significantly higher cumulative incidence of relapse (p = 0.003), inferior overall survival (p = 0.001) and relapse free survival (p − patients. NGS-MRD was predictive of inferior outcome in intermediate cytogenetic risk and demonstrated potential in favorable cytogenetic risk AML. PI NGS-MRD− patients had a significantly improved survival as compared to patients who became NGS-MRD− subsequently indicating that kinetics of NGS-MRD clearance was of paramount importance. NGS-MRD identified over 80% of cases identified by flow cytometry at PI time point whereas FCM identified 49.3% identified by NGS. Only a fraction of cases were NGS-MRD− but FCM-MRD+. NGS-MRD provided additional information of the risk of relapse when compared to FCM-MRD. We demonstrate a widely applicable, scalable NGS-MRD approach that is clinically informative and synergistic to FCM-MRD in AML treated with conventional therapies. Maximum clinical utility may be leveraged by combining FCM and NGS-MRD modalities.

INTRODUCTION Many new markers are being evaluated to increase the sensitivity and applicability of multicolor flow cytometry (MFC)-based measurable residual disease (MRD) monitoring. However, most of the studies are limited to childhood B-cell lymphoblastic leukemia/lymphoma (B-ALL), and reports in adult B-ALL are extremely scarce and limited to small cohorts. We studied the expression of CD304/neuropilin-1 in a large cohort of adult B-ALL patients and evaluated its practical utility in MFC-based MRD analysis. METHODS CD304 was studied in blasts from adult B-ALL patients and normal precursor B cells (NPBC) from non-B-ALL bone marrow samples using MFC. CD304 expression intensity and pattern were studied with normalized-mean fluorescent intensity (nMFI) and coefficient of variation of immunofluorescence (CVIF), respectively. MFC-based MRD was performed at end of induction (EOI; day-35), end of consolidation (EOC; day 78-80), and subsequent follow-up (SFU) time points. RESULTS CD304 was positive in 120/214(56.07%) and was significantly associated with BCR-ABL1 fusion (P = .001). EOI-MRD and EOC-MRD were positive in 129/214(60.3%) and 50/81(61.72%), respectively. CD304 was positive in a significant percentage of EOI (48%, 62/129) and EOC (52%, 26/50) MRD-positive B-ALL samples. Its expression was retained, lost, and gained in 73.7%, 26.3%, and 11.3% of EOI-MRD and 85.7%, 14.3%, and none of EOC-MRD samples, respectively. Low-level MRD (

The upcoming 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours is part of an effort to hierarchically catalogue human cancers arising in various organ systems within a single relational database. This paper summarizes the new WHO classification scheme for myeloid and histiocytic/dendritic neoplasms and provides an overview of the principles and rationale underpinning changes from the prior edition. The definition and diagnosis of disease types continues to be based on multiple clinicopathologic parameters, but with refinement of diagnostic criteria and emphasis on therapeutically and/or prognostically actionable biomarkers. While a genetic basis for defining diseases is sought where possible, the classification strives to keep practical worldwide applicability in perspective. The result is an enhanced, contemporary, evidence-based classification of myeloid and histiocytic/dendritic neoplasms, rooted in molecular biology and an organizational structure that permits future scalability as new discoveries continue to inexorably inform future editions.

Hematopoietic stem and progenitor cell (HSPC) mobilization regimens in multiple myeloma typically use filgrastim (GCSF) alone or combination of GCSF with plerixafor or high-dose cyclophosphamide. Murine model and human studies have shown HSPC mobilization potential of bortezomib. A total of 37 patients underwent mobilization using bortezomib 1.3 mg/m2 on day 1, 4, 8 and 11, cyclophosphamide 1 g/m2 on day 8 and 9, and GCSF 10 μg/kg from day 10 (B-Cy-GCSF). This regimen was compared with our earlier cohort of patients where cyclophosphamide was given at dose of 1 g/m2 on day 1 and day 2 followed by GCSF 10 μg/kg from day 4 (Cy-GCSF). In B-Cy-GCSF group, median CD34 cells collected were 9.21 × 106/kg (range 4.95–17.1) while in the Cy-GCSF cohort, the median CD34 cell yield was 8.2 × 106/kg (0.4–24.2). Target CD34 cells yield of 5 × 106/kg was achieved with single apheresis in 58.6% of patients after B-Cy-GCSF mobilization as compared to 44.3% in Cy-GCSF group (p = 0.07). Three patients failed mobilization after Cy-GCSF, while no patients failed mobilization in bortezomib group. Addition of bortezomib to Cy-GCSF mobilization showed a trend towards increased CD34 collection and reduced need for apheresis sessions.

Panel based next generation sequencing was performed on a discovery cohort of AML with RUNX1-RUNX1T1. Supervised machine learning identified NRAS mutation and absence of mutations in ASXL2, RAD21, ...

INTRODUCTION Mixed-phenotype acute leukemia (MPAL) accounts for 1.2% to 5% of acute leukemia across age groups with intermediate prognosis. We evaluated clinicoepidemiological profiles and outcomes of MPAL. METHODS Records of children younger than 15 years of age with acute leukemia from January 2010 to December 2016 were reviewed on the basis of the MPAL WHO 2008 criteria. Treatment was uniform with a modified MCP-841 protocol. Descriptive analysis tools were used. Outcomes were measured by the Kaplan-Meier method on MedCalc, version 14.8.1. RESULTS Among 3830 children with acute leukemia in the study period, 2892 received treatment from our center, of whom 24 (0.83%) had MPAL, median age 9 years, with a male:female ratio of 3:1, and median white blood cell of 13.4×10/L. Common immunophenotypes were B/myeloid-12 (50%), T/myeloid-9 (37.5%), and B/T-lymphoid-3 (12.5%). Some B/myeloid cases had abnormal cytogenetics. Seventeen patients were evaluable for outcome. Sixteen patients underwent postinduction bone marrow and 13 (81%) achieved morphologic remission. Thirteen patients underwent flow cytometry-based minimal residual disease evaluation; 9 (69%) were

INTRODUCTION Juvenile myelomonocytic leukemia (JMML) is a rare childhood neoplasm (

High-sensitivity multicolour flow cytometry (MFC)-based B-lymphoblastic leukaemia (B-ALL) measurable residual disease (BMRD) assay is increasingly being used in clinical practice. Herein, we describe six consistently present low-level populations immunophenotypically mimicking abnormal B-ALL blasts in 441 BMRD samples from 301 children. These included CD19+ CD123+ plasmacytoid dendritic cells differentiating from lymphoid precursors, CD10+ transitional B cells with CD10+ /CD38dim-to-negative/CD20bright/CD45bright phenotype, CD19+ natural killer (NK) cells, CD73bright/CD10+ mesenchymal stromal/stem cells, CD73bright/CD34+ endothelial cells, and a CD34+ CD38dim-to-negative/CD10- /CD20bright/CD45bright subset of mature B cells. We provide the proportions, comprehensive immunophenotype, and practical clues for proper identification of these low-level populations. Knowledge regarding the presence and immunophenotype of these mimics is essential for accurate interpretation in high-sensitivity MFC-BMRD analysis.

The use of pediatrics-inspired protocols in adolescent and young adult (AYA) acute lymphoblastic leukemia (ALL) results in superior survival compared with the adult protocols. Pediatrics-inspired protocols carry an increased risk of toxicity and treatment-related mortality in low resource settings, which can offset the potential benefits. We studied the outcomes and prognostic factors in the treatment of AYA ALL with a pediatrics-inspired regimen. We retrieved data regarding demographics, investigations, treatment details, and toxicities from the electronic medical records of patients diagnosed with ALL in the 15- to 25-year-old age group who were initiated on a modified Berlin-Frankfurt-Münster 90 (BFM-90) protocol between January 2013 and December 2016 at the Tata Memorial Centre. A total of 349 patients in the 15- to 25-year-old age group were treated with a modified BFM-90 protocol. The use of this pediatrics-inspired protocol resulted in a 3-year event-free survival (EFS) and overall survival (OS) of 59.4% and 61.8%, respectively. Only 15 patients underwent an allogeneic stem cell transplant. Minimal residual disease (MRD) persistence postinduction emerged as the only factor predictive of poor outcomes. A modified BFM-90 protocol is an effective and safe regimen for AYA ALL with an OS and EFS comparable to the published literature.

The high expression of brain and acute leukemia, cytoplasmic (BAALC) and ETS-related gene (ERG) has been reported to influence the outcome in acute myeloid leukemia (AML), but due to limited prospective studies, their role as prognostic factors is unclear. At diagnosis, the prognostic value of BAALC and ERG expression with respect to other cytogenetic and molecular markers was analyzed in 149 AML patients. Patients were divided into quartiles which resulted in the formation of four groups (G1-G4) based on expression values of BAALC and ERG and clinical response defined across groups. Groups with similar survival probabilities were merged together and categorized subsequently as high versus low expressers. Patients with high BAALC and ERG expression had significantly lower overall survival (OS; BAALC: p = 0.001 at 5 years 29.4% vs. 69.8%; ERG: p < 0.0001 at 5 years 4% vs. 50.4%) and disease-free survival (BAALC: p = 0.001 at 5 years 19.5% vs. 69.8%; ERG: p < 0.0001 at 5 years 4.2% vs. 47%). Patients were further stratified combining BAALC and ERG expression in an integrative prognostic risk score (IPRS). After a median follow-up of 54 months (95% CI 45-63 months) among survivors, IPRS for high versus low expressers was a significant predictor for OS (BAALC + ERG: 4% vs. 71.6%, p < 0.0001) and DFS (BAALC + ERG: 4.5% vs. 74.1%, p < 0.0001). In a multivariate model, IPRS of BAALC + ERG expression retained prognostic significance for OS (hazard ratio [HR] 2.96, 95%CI 1.91-4.59, p < 0.001) and DFS (HR 3.61, 95%CI 2.26-5.76, p < 0.001).

Introduction The monitoring of a patient's response to chemotherapy, called, measurable residual disease (MRD) is one of the most important predictors of outcome in Acute Myeloid Leukemia (AML). Although universally applicable, FCM-MRD for AML suffers from low sensitivity as compared to precursor B lineage acute lymphoblastic leukemia. Here, we evaluated the clinical utility of error corrected next generation sequencing (NGS) to detect MRD (NGS-MRD) in AML using single molecule molecular inversion probes (smMIPS). We compare NGS-MRD and FCM-MRD and determine their impact on patient outcome. We demonstrate that error corrected NGS-MRD at early timepoints in therapy is an independent and significant predictor of outcome in patients of AML treated with conventional therapies. Methods We created a 35 gene "hotspot" panel comprising of a pool of 302 smMIPS. In brief, this panel covers regions of 35 commonly mutated genes in AML.FLT3-ITD were detected using a novel one-step PCR based NGS assay. Post mapping, singleton reads (originating from one UMI) were discarded and consensus family based variant calling was performed. We then created a site and mutation specific error model to ascertain the relevance of an observed variant at each site. A limit of detection (LOD) experiment demonstrated a lower detection limit of 0.05%. For FLT3-ITD the LOD was 0.002%. A total of 393 adult patients of AMLwere accrued over a period of six years.Patients were treated with standard 3+7 induction followed by 3 doses of HiDAC. Allogeneic bone marrow transplantation was offered where feasible. Somatic mutations at diagnosis were evaluated using a smMIPS based 50 gene myeloid panel which was applicable to 327 patients [83.2% of AMLs, median 2 mutations per case (range 1 - 6 trackable mutations)].MRD assessment could be performed in 201 adult patients of AML in morphological remission (not performed in the rest because of suboptimal quality DNA at MRD time points or missing sample).Samples were sequenced on multiple S4 flow cells of a NovaSeq 6000 using 150PE chemistry.FCM-MRD was obtained from the bone marrow at end of induction (PI, n=200) and end of first consolidation cycle (PC, n=98). NGS-MRD sample also obtained at the same time points (PI, n=196& PC, n=127) from the bone marrow (n=266) or peripheral blood (n=45). Results The interaction of mutations that were trackable at diagnosis can be seen in Figure 1A. A total of 345 mutations could be detected in 196 patients (Figure 1B) with a median VAF of 1.01% [0.82% after exclusion of mutations in DNMT3A, TET2, ASXL1 (DTA) genes; (median of 2 mutations for PI and one for PC timepoint)]. The median consensus read coverage was 11,127 for the smMIPS assay, whereas for the FLT3-ITD assay it was 13,96,366.The median follow-up of the cohort was 42.3 months. The presence of NGS-MRD (70.9%) was associated with inferior overall survival (OS; p=0.001) [hazard ratio(HR)- 2.24; 95% confidence interval (CI)- 1.47 to 3.43] and relapse free survival (RFS; p=0.0002) [HR- 2.28; 95% CI- 1.58 to 3.31] at PI time point as well as PC time points [40.94% positive; OS (p=0.008)(HR- 1.92; 95% CI- 1.14 to 3.22) and RFS (p=0.004)(HR- 1.90; 95% CI- 1.18 to 3.05)].Similarly, FCM-MRD (44%) was predictive of inferior OS (p=0.0002)(HR- 2.08; 95% CI- 1.38 to 3.13)and RFS (p=0.0008)(HR- 1.81; 95% CI- 1.26 to 2.60) at PI as well as PC time points [21.4% positive, OS (p=0.04)(HR- 1.87; 95% CI- 0.89 to 3.91) and RFS (p=0.001)(HR- 2.38; 95% CI- 1.17 to 4.81)]. On multivariate analysis post induction NGS MRD emerged as the most important independent prognostic factor predictive of inferior outcome for OS [HR- 1.94; 95% CI-1.15 to 3.27; (p Conclusion In conclusion, we demonstrate that error corrected panel-based sequencing is feasible for MRD monitoring in AML and may offer an advantage over existing techniques. Maximum clinical utility may be leveraged by combining FCM and NGS modalities. Figure Disclosures No relevant conflicts of interest to declare.

We document the characteristics of BCR-ABL kinase domain mutations (KDM) in the largest study from India comprising of 385 patients and demonstrate that more than half (51.9%) of these patients have detectable abnormalities in the KD both in adult and in pediatric chronic myelogenous leukemia (CML). These comprise singly occurring missense mutations (25.5%), polyclonal/compound point mutations (4.9%), and insertions/deletions (29.6%). Missense mutations were most commonly seen in the imatinib-binding region followed by the P-loop. The commonest mutation in our dataset was T315I. Other common missense mutations were Y253H, M244V, and F317L. A high prevalence of BCR-ABL exon7 deletion (p.R362fs*) was also seen (25.5% of the entire cohort), whereas the 35bpintron-derived insertion/truncation mutation detected in 12 patients. In the pediatric age group, 58.8% of patients harbored missense mutations, polyclonal/compound mutations as well as insertions and deletions. We detected 11 novel mutations (seven missense mutations and four insertions/deletions).

Background: The expression of CD20 in precursor B-cell ALL has been associated with poor outcomes. The addition of rituximab with intensive chemotherapy in this subset of ALL has led to improvement in the event-free survival. Further increment in outcomes require novel approaches. Bortezomib is an active drug in relapsed ALL as well as has synergistic activity with rituximab in B-cell lymphomas; thus the addition of bortezomib to rituximab and chemotherapy may improve the outcomes in CD20-positive precursor B-cell ALL. Methods: We conducted a phase II study to test the activity of bortezomib and rituximab in combination with a paediatric inspired regimen during induction therapy in newly diagnosed adolescent and adults (>14 years of age) with CD20-positive, Philadelphia (Ph)-negative precursor B-ALL, with bone marrow measurable residual disease (MRD) negativity at the end of induction (EOI) as the primary endpoint. Results: From December 2017 through August 2019, a total of 35 patients were enrolled. A total of 70.99% patients achieved EOI MRD negative status. MRD negative rates improved to 88% post consolidation. There was no significant increase in toxicity with addition of bortezomib and rituximab to standard chemotherapy. The incidence of neuropathy was 26% ( Conclusion: The combination of bortezomib, rituximab and paediatric-inspired ALL regimen is active and well tolerated in in de-novo CD20 positive Ph-negative precursor B-ALL. Disclosures No relevant conflicts of interest to declare.

Ploidy, besides known translocations in lymphoblasts, is a strong predictor of prognosis in B- cell progenitor acute lymphoblastic leukemia (BCP-ALL). While hyperdiploidy with >50 chromosomes shows a favourable outcome, hypodiploidy with

Atypical breakpoints and variant APL cases involving alternative chromosomal aberrations are seen in a small subset of acute promyelocytic leukemia (APL) patients. Over 7 different partner genes for RARA have been described. Although rare, these variants prove to be a diagnostic challenge and require combination of advanced cytogenetic and molecular techniques for accurate characterization. Heterogeneity occurs not only at the molecular level but also at clinico-pathological level influencing treatment response and outcome. In this case series we describe the molecular heterogeneity of APL seen in a single tertiary referral centre with a focus on seven variant APL cases from a single tertiary cancer center in India over a period of two and a half years. We discuss five cases with PLZF-RARA fusion and two novel PML-RARA variants, including a Bcr3 variant involving fusion of PML exon4 and RARA exon3 with an additional 40 nucleotides originating from RARA intron2, another involving exon 6 of PML and exon 3 of RARA with addition of 126 nucleotides, which mapped to the central portion of RARA intron 2 To the best of our knowledge this is the first of kind case series from India

IL-6 activity in normal plasma cells (nPCs) and abnormal plasma cells (aPCs) is CD126 (subunit of IL-6 receptor) dependent. We quantified CD126 expression on nPCs and aPCs in monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma (SMM), and multiple myeloma (MM). CD126 was detected on all nPCs and aPCs indicating that CD126 does not have diagnostic utility. CD126 expression was higher in aPCs than in nPCs in 85% SMM but only 41% MGUS and there was evidence that CD126 was higher in aPCs than nPCs in the SMM (p = .048) but not MGUS (p = .96) patients. There is also a greater association between nPC and aPC CD126 expression in low risk MGUS than observed in high risk MGUS and SMM, suggesting normal regulation of CD126 decreases with disease progression. Future studies need to elucidate the role of bone marrow milieu versus escape from normal CD126 regulation in malignant transformation of clonal plasma cells.

Introduction: Juvenile myelomonocytic leukaemia (JMML) is a clonal haematopoietic disorder occurring in pediatric age group usually characterized by uncontrolled granulocytic and monocytic lineage proliferation and a poor outcome. JMML is characterised by aberrant signal transduction of the RAS signalling pathways, usually manifesting in molecular alteration of one of the five cardinal genes: NF1, NRAS, KRAS, PTPN11 and CBL. Recent high-throughput studies have started to push the horizon of JMML associated mutations wider and have proposed molecular-based risk algorithms. We comprehensively evaluated the genomic profile of JMML that were referred to our hospital for diagnosis and treatment. Methods: We developed a 51 gene (103 kB) low-cost targeted sequencing myeloid panel based on single molecule molecular inversion probes. This focussed panel interrogated sets of genes implicated in pathogenesis of myeloid malignancies. A total of 50 children with clinical and pathological features of JMML were sequenced at high coverage using this assay on an Illumina MiSeq. Results:The median age of our cohort was 2 years, with a male preponderance. Among the 50 patients, 43 (86%) harboured mutations in one of the RAS/MAPK pathway genes. The most frequently mutated gene in our cohort was PTPN11 (14, 28%), and NRAS (14, 28%), followed by NF1 mutation in 22% (11) cases (Figure 1). Interestingly, 20% (10) of children had more than one mutation, with 5 cases harbouring two RAS pathway mutations. Of these 5 patients, one patient harboured two coexistent mutations in the NF1 gene, three patients had coexistent PTPN11 and NF1 mutations and one patient had a coexistent NF1 and NRAS mutations. Additionally, two patients also had an ASXL1 mutation, coexistent with NF1 and NRAS mutations respectively. Other non-RAS pathway mutations involved ABL1, ATRX, SETBP1, SH2B3 and ZRSR2 genes. The median variant allele frequency of RAS pathway mutations detected was 40.75%. Monosomy 7 was detected in 32% (16) patients, and five of these did not harbour any RAS pathway mutations. The follow up data revealed that 37 (74%) of these patients have succumbed to the disease. In our cohort, only five patients received an allogenic stem cell transplant, owing to economic constraints; two of these patients have succumbed to the disease. The median time period from diagnosis to death was 7.2 months in the cohort. On survival analysis, patients with PTPN11 mutations showed a trend to shorter overall survival, compared to their wildtype counterparts (p=0.7, median OS 10.6 months vs 38.1 months). Additionally, patients harbouring more than one mutation also showed a trend to shorter OS (p=0.64, median OS 10.3 months vs 38.1 months). Among the thirteen patients who are still on regular follow-up, two patients have relapsed with disease progression to acute myeloid leukemia and T/myeloid mixed phenotypic acute leukemia respectively. Conclusion: Our study represents the largest cohort of JMML from a single centre in the Indian subcontinent. This study depicted that almost 90% cases of JMML harbor at least one mutation with 86% harbouring at least one RAS pathway mutation. Presence of PTPN11 mutations and co-existence of more than one mutation may be the major determinants of outcome in JMML. Figure 1 Disclosures No relevant conflicts of interest to declare.

Background: Minimal Residual Disease (MRD) is a powerful predictor of event-free survival in acute lymphoblastic leukemia (ALL). However, as T-ALL is less common, MRD studies are limited, often with small cohorts, and even fewer have been done by flowcytometry-based MRD (FC-MRD). There have also been different time-points such as Post-Induction (PI-MRD), and late or Post-Consolidation (PC-MRD) that have shown significant correlation with overall, event, and relapse-free survival (OS, EFS & RFS). As the available literature is still not conclusive, we investigated the impact of FC-MRD on survival in childhood T-ALL at a large tertiary cancer care centre in India. Methods: Children less than 15-years age diagnosed with T-ALL from Jan-2014 to May 2018 were treated uniformly on a modified MCP-841 protocol that included a 4-drug induction (vincristine, prednisolone, l-asparaginase, daunomycin), and consolidation with high-dose cytarabine (24gm/m2 in 3 equal legs for children below 3-years, and 16gm/m2 in two equal legs, for 3 or more years age). Post-consolidation therapy followed the pattern of Interim Maintenance, two Delayed Intensification cycles, and 18 months of Maintenance. Central Nervous System (CNS)-directed therapy consisted of intrathecal methotrexate in all cycles, and those with CNS involvement received additional Cranial Radiation of 18Gy. In early-thymic-precursor (ETP-ALL) immunophenotype patients, dexamethasone replaced prednisolone in Induction. The protocol did not include High-Dose Methotrexate. FC-MRD was estimated by 10-color FC-MRD assay on Navios flow-cytometer (Beckman Coulter, Inc.) at Post-Induction(day-35), and Post-Consolidation(day-78) for those PI-MRD positive(+ve). FC-MRD was analyzed on Kaluza® software v-1.3. Any detectable value was taken as positive. Statistical analysis was performed using MedCalc Statistical Software®. Results: Of 368 eligible patients diagnosed at our centre in the study period, 81 did not undergo PI-MRD (14- Induction deaths, 13- treatment abandonment, 54- referral to other institute/ time-point missed/ did not consent/ other reasons). Another 18 abandoned treatment within 100 days of diagnosis and were also excluded. In the remaining 269, median age was 10-years (range:1-15), M:F-3.8:1. Median presenting WBC was 96.7 x 103/cmm (range:1.14-849), and thirteen patients had ETP. PI-MRD was positive in 125(46%) patients (median MRD -0.3%, range:0.0007-43.6%) of which 58(46.4%) developed medullary relapse, compared to 17 of 144(11.6%) for PI-MRD negative(-ve) patients, with Hazard Ratio (HR) for risk of medullary-relapse for PI-MRD+ve being 5.02(95% CI:3.16-7.96; p Conclusion: We conclude that 10-color FC-MRD done Post-Induction and Post-Consolidation detecting any residual disease reliably identifies those at highest risk of relapse and any other event. PI-MRD+ is an independent, and also the most important risk-factor for any event, and if PC-MRD is also positive, relapse occurs early. Figure 1 Disclosures No relevant conflicts of interest to declare.

Introduction: Core binding factor acute myeloid leukemia (CBF-AML) is one of the commonest subtypes of AML characterized presence of t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22). It is characterised by a high frequency of somatic mutations especially in RAS and tyrosine kinase signalling pathways. Here we investigated the feasibility of improving risk prediction of CBF-AML using machine learning algorithms. Methods: We developed a next generation sequencing panel that targeted 50 genes implicated in the pathogenesis of myeloid malignancies using single molecule molecular inversion probes. This panel was used to sequence 106 patients of CBF-AML accrued over a six year period (March 2012 - December 2018) treated with conventional "3 + 7" chemotherapy. Post data analysis, we devised a supervised machine learning (ML) approach for identification of mutations most likely to predict for favorable outcome in CBF-AML. We included somatic mutations in genes occurring in CBF-AML at a frequency of >5%. A total of 11 variables were included for feature selection to predict for favorable outcome (including mutations in ASXL2, CSF3R,FLT3, KIT, NF1, NRAS, RAD21, TET2 and WT1 genes as well as mutation burden). Approaches for supervised ML were naïve bayes, generalized linear model, logistic regression, deep learning and random forest methods. Based on the ML results top 6 selected variables were allotted an individual score. A final score for that case was devised as a sum total of the individual scores. These sum were used to generate a genetic risk for a patient. Overall survival (OS) was calculated from date of diagnosis to time of last follow up or death. Relapse free survival (RFS) was calculated from date of CR till time to relapse or death or last follow up if in CR. Results of the genetic risk were analyzed for their impact on OS and RFS using log rank test. Multivariate analysis was performed using cox proportional hazards regression model. Results: The median follow up of the cohort was 27.6 months. A total of 181 somatic mutations were identified in this subset of AML with 86.7% harbouring at least one somatic mutation (median = 2). Based on ML data, a genetic score was formulated that incorporated mutations in RAD21, FLT3, KIT D816, ASXL2, NRAS genes as well as high mutation burden (≥2) into two genetic risk classes (favorable risk and poor ML derived genetic genetic risk). Patients classified as poor genetic risk had a significantly lower OS [median OS: 34.8 months; 95% confidence interval (CI) (14.2-34.8); p=0.0086] and RFS [median RFS: 17.9 months; 95%CI (12.7-33.6); p=0.0043] as compared to patients with favorable genetic risk (median OS and RFS not reached). These results can be seen in Figure 1. On multivariate analysis poor genetic risk was the most important independent risk factor that predicted for inferior OS [hazard ratio(HR), 2.7; 95% CI 1.3 to 5.7] and RFS (HR, 2.6; 95% CI:1.3 to 5.1). Conclusions In a proof of concept, we describe a novel ML derived genomics scoring model that provides a mechanism to risk stratify CBF-AML, a seemingly homogeneous disease entity. This study, to the best of our knowledge represents a novel application of ML to CBF mutated AML. Our data indicates that this scoring system will be useful in identifying CBF mutated AML patients who are at higher risk of relapse and distinguishes them from patients who are truly good risk. Figure 1 Disclosures No relevant conflicts of interest to declare.

The risk of progression to multiple myeloma (MM) from the precursor condition smoldering MM (SMM) varies considerably among individual patients. Reliable markers for progression to MM are vital to advance the understanding of myeloma precursor disease and for the development of intervention trials designed to delay/prevent MM. The Mayo Clinic and Spanish PETHEMA have proposed models to stratify patient risk based on clinical parameters. The aim of our study was to define the degree of concordance between these two models by comparing the distribution of patients with SMM classified as low, medium and high risk for progression. A total of 77 patients with SMM were enrolled in our prospective natural history study. Per study protocol, each patient was assigned risk scores based on both the Mayo and the Spanish models. The Mayo Clinic model identified 38, 35 and four patients as low, medium and high risk, respectively. The Spanish PETHEMA model classified 17, 22 and 38 patients as low, medium and high risk, respectively. There was significant discordance in overall patient risk classification (28.6% concordance) and in classifying patients as low versus high (p < 0.0001), low versus non-low (p = 0.0007) and high versus non-high (p < 0.0001) risk. There is a need for prospectively validated models to characterize individual patient risk of transformation to MM.

Natural killer (NK) cells are involved in immune surveillance of various malignancies, including multiple myeloma (MM).[1][1] IPH2101 is a fully human monoclonal antibody that blocks HLA-C binding KIR2D receptors (KIR2DL/DS-1, -2 -3) expressed on the surface of NK-cells, enhancing their cytotoxicity

Introduction: Mainstay of chemotherapy in acute myeloid leukemia (AML) is induction with a goal to achieve morphological complete remission (CR) as evident by less than 5% blasts. Post remission strategies then focus on either consolidation chemotherapy or allogeneic bone marrow transplantation (aBMT). However, not all patients by this remission criterion achieve long term remission and a subset of patients' relapse. This relapse originates from further expansion chemoresistant clones. Detection of minimal residual disease (MRD) following chemotherapy, early in the course of treatment, is highly predictive of outcome and offers a window of opportunity to intensify treatment and prevent relapse as seen in ALL. Here, we describe assessment of immunophenotypic MRD using a 10-colour two tube assay and a combination of difference from normal and leukemia associated immunophenotype (LAIP) approach in patients of adult AML. Methods: We accrued 310 patients of adult (>18 years) AML, other than with t(15;17), over a 66-month period (1st July 2012- 31st December 2017) after obtaining informed consent. All patients received standard induction chemotherapy. MRD testing was done post induction and after first consolidation with high dose cytarabine. Patients accrued from 1st July 2012 to 28th February 2015 (85 patients) were processed using a three tube 8 colour MRD assay. Subsequently samples of 225 patients were processed using a two tube 10 colour MRD assay. Identical panel was used for diagnostic sample, post induction and post consolidation. 500,000 events were acquired per tube with the 3-tube assay and 1.6 million events per tube obtained per tube with the 2 tube, 10 colour assay. Analysis of MRD was done using Kaluza 1.3 by a combination of difference from normal approach that focused on the development of Myeloid progenitors to mature cells and LAIP approaches. Cytogenetic studies by conventional karyotyping and FISH was done as per NCCN version 2 2014 recommendations. Patients were classified into favorable, intermediate and poor cytogenetic risk. The presence of FLT3-ITD, NPM1 and CEBPA mutations were detected by a fragment length analysis-based assay. Overall survival (OS) was calculated from date of diagnosis to time of last follow up or death. Relapse free survival (RFS) was calculated from date of CR till time to relapse or death or last follow up if in CR. Results of the MRD assays, cytogenetic and molecular risk groups were analyzed for their impact on OS and RFS using log rank test. Results: The median age of entire cohort was 33 years (M : F = 1.6 : 1). Based on cytogenetics, 35.1% were classified as favorable risk whereas 52.5% and 12.2% were intermediate and poor risk respectively. FLT3-ITD, NPM1 and CEBPA mutations were detected in 21.9%, 29.0% and 7.7% of patients respectively. Post induction MRD was assessed in 298 patients of which 114 (38.3%) had detectable residual disease (range 0.004-22.6%, median:0.9%). Post consolidation MRD was assessed in 186 patients of which 49 (26.4%) were MRD positive (range 0.002-19.8%, median: 0.37%).The 3 year OS, RFS and median RFS of the entire cohort was 59.0%, 44.8% and 18.7 months respectively. Poor risk cytogenetics as expected was predictive of inferior OS (median OS = 14.6 months vs not reached, p=0.05) as well as RFS (median RFS = 9.3 months vs 18.6 months, p=0.003 respectively). FLT3, NPM1 and CEBPA mutations were not informative as predictors of outcome.The presence of MRD at post induction time point predicted an inferior OS [(p=0.08), HR:1.53; 95% CI (0.93-2.51)] & RFS [(p=0.0002), HR:2.14; 95% CI (1.4-3.3)] as compared to the MRD negative group. Similarly, patients harboring MRD at the end of consolidation had an inferior OS [(p=0.04), HR:1.83; 95% CI (0.94-3.6)] & RFS [(p=0.02), HR:1.79; 95% CI (1.04-3.09)] as compared to the MRD negative group. On multivariate analysis post induction FCM MRD emerged as the most important independent prognostic factor predictive of inferior outcome for RFS [(p=0.01); HR:2.14; 95% CI (1.17 - 3.4)] followed by poor cytogenetic risk [(p=0.05); HR:1.8; 95% CI (1.0 to 3.26)]. Conclusion: Our data demonstrates that MRD by flow cytometry at end of induction as well as consolidation are important prognostic factors together with known factors such as high risk cytogenetics. AML MRD is a very useful guide for post remission strategies in AML and should be incorporated into routine treatment algorithms. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Background: Proteasome inhibitors (PI) have become integral part of front-line treatment of multiple myeloma. Murine model experiments have shown mobilization of hematopoietic stem cells from bone marrow to peripheral blood after PI administration via down regulation of very late antigen 4 (VLA-4) which mediate adherence of hematopoietic stem cells to the bone marrow microenvironment via interaction with vascular cell adhesion molecule (VCAM-1). Human studies with bortezomib in combination with G-CSF for mobilization have yielded encouraging results with no additional toxicity and no malignant plasma cell mobilization was observed. Cyclophosphamide based chemo-mobilization offers advantage in term of higher stem cell yield and is able to overcome adverse impact of prior lenalidomide therapy on stem cell harvest. In the current study we added bortezomib to cyclophosphamide-GCSF (B-Cy-GCSF) chemo-mobilization regimen to study the effect of bortezomib on stem cell harvest and compared this with our earlier protocol of only cyclophosphamide-GCSF (Cy-GCSF) mobilization. Methods: Patients of multiple myeloma aged between 18 to 70 years were eligible for the study in the period between March 2016- June 2018. Patients after induction therapy achieving at least partial response and having no more than grade 1 peripheral neuropathy were enrolled. Patients received bortezomib at a dose of 1.3 mg/m2 on day 1, 4, 8 and 11 and cyclophosphamide (Cy) was administered at a dose of 1 g/m2 on day 8 and 9 followed by G-CSF 10µg/kg in two divided doses from day 11 onwards till target stem cell collection of at least 5 X 106/Kg. The peripheral blood CD34 (PB CD34) counts were monitored from day 14 and harvest was initiated when it reached above 20 cells/µL. The peak PB CD34 count achieved, the number of days of harvest required, the CD34 dose yield and the engraftment kinetics were recorded and compared with earlier patients who had undergone Cy-GCSF chemo-mobilization. These patients had received Cy 1 g/m2 on d1 and d2, G-CSF 10 mcg/kg from d4 onwards and PBCD34 monitored from d7 onwards. Result: A total of 37 patients were enrolled between March 2016 and June 2018. Median age of study cohort was 46 years (range 27-63) and 27 (73 %) were males. Median lines of therapy received were 1 (range 1 to 2) and 8 (21.6 %) had received lenalidomide prior to stem cell harvest. The median peak peripheral blood CD34 cell counts 71.3 cells /µL (range 27.5 -306). Median CD34 cells collected were 9.21 X 106 /Kg (range 4.95-17.1). Target CD34 cell collection was achieved after a median of one day harvest (range 1-2). Median time to neutrophil and platelet engraftment was 11.5 and 13.5 days respectively. These results were compared with 88 patients who had undergone Cy-GCSF chemo-mobilization earlier at our center from May 2008 till February 2016 as seen in Table1 . In Cy- G-CSF cohort, median number of harvest required for target CD34 was 2 (range 1-4) and median CD34 cell yield was 8.2 X 106/Kg (0.4-24.2). Target CD34 cells yield of 5 X 106/Kg was achieved with single apheresis in 58.6% of patients after B-Cy-GCSF mobilization as compared to 44.3% in Cy-G-CSF group, although this was not statistically significant (p=0.1). While 3(3.4 %) had failed chemo-mobilization after Cy-GCSF, none of patients in bortezomib group had mobilization failure. Conclusion: Patients undergoing B-Cy-GCSF mobilization have higher stem cell yield and required less days of harvest. This strategy should be explored in a larger cohort of patients. Disclosures No relevant conflicts of interest to declare.

Infectious mononucleosis is characterized by an intensive lymphoproliferation with atypical forms which sometimes resemble with acute leukemia or malignant lymphoproliferative diseases. Flow cytometric analysis of lymphocytes shows a typical phenotype but unawareness of it may lead to misdiagnosis of malignant lymphoproliferative diseases. Herewith we present an immunophenotypic profile in a case of acute infectious mononucleosis and review of literature.