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Outcomes and life expectancy for patients with multiple myeloma (MM) have improved substantially over the last two decades with advancements in therapy, including autologous stem cell transplantati...

Objective: The diagnostic criteria for secondary hemophagocytic lymphohistiocytosis (HLH) have not been validated in the critically ill adult population. We set out to evaluate the performance of diagnostic criteria and determine the ferritin cutoff in critically ill adults. Design: A retrospective single-center study. Setting and Patients: Patients admitted to intensive care unit between 2008 and March 2010. Data were collected on consecutive patients who had ferritin measured. Charts were reviewed for the diagnostic criteria of HLH and components of Hscore. Measurements and Main Results: A total of 445 patients had a ferritin level measured during the study period. A diagnosis of HLH was made for 10 patients. Having 5 of 6 criteria had a specificity of 97% and a sensitivity of 70%. Hemophagocytosis was found in 41 (47.1%) of 87 bone marrow biopsies. Two hundred thirty-one patients had a ferritin level above 500 ng/dL. When determining the odds of HLH being clinically diagnosed, the optimal cut point for ferritin was 1197 ng/dL. When determining the odds of HLH based on the Hscore, the best cutoff was 143.5 (sensitivity of 90% and specificity of 90%) and patients who had HLH in our study population had an Hscore of 203.8 ± 64.9. Conclusion: In this cohort of critically ill patients, the HLH criteria are specific for HLH but not sensitive. Critically ill patients can have a higher incidence of hemophagocytosis without HLH. A higher ferritin cutoff in combination with 5 other clinical criteria is comparable to the Hscore for the recognition of HLH in the critically ill population.

Acute leukemias of ambiguous lineage (ALAL) are rare hematologic malignancies with poor outcomes. Retrospective studies have suggested that acute lymphoblastic leukemia (ALL) regimens are more effective than acute myeloid leukemia (AML) regimens. We retrospectively examined the effectiveness of the widely-used adult ALL regimen hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyperCVAD) as initial therapy in patients with ALAL at five academic institutions. Twenty-five patients were identified, including 23 with mixed phenotype acute leukemia (MPAL) and two with acute undifferentiated leukemia. Five of 8 tested (63%) had FLT3-ITD and 3 of 25 (12%) were Philadelphia chromosome-positive. The complete remission (CR) rate was 76%, with CR with incomplete count recovery (CRi) in an additional 8%, for an overall response rate of 84%. Median number of cycles to CR/CRi was 1. There were no deaths in the first 30 days. Of the 21 patients achieving CR or CRi, 14 (66%) proceeded to allogeneic hematopoietic stem cell transplantation. With a median follow-up time of 31.6 months, median overall survival for the entire cohort was not reached, and the estimated 2-year survival was 63%. HyperCVAD can be considered an effective and tolerable front-line regimen for patients with ALAL, and warrants further prospective study.

We describe two patients with acute promyelocytic leukemia (APL) with an unusual immunophenotype with co-expression of myeloperoxidase (MPO) with cytoplasmic CD3 (cCD3) representing myeloid and T-lineage differentiation. Both harbored FLT3-ITD mutations. One additionally had a deletion in the PML gene affecting the primer binding site, thus limiting measurable residual disease (MRD) analysis during follow-up. Both patients achieved durable remission with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO)-based therapy, thus mitigating the need for repetitive conventional chemotherapy cycles and allogeneic stem cell transplantation. Our report highlights the complexity and challenge of diagnosis and management of APL due to the variant immunophenotype and genetics, and underscores the importance of synthesizing information from all testing modalities. The association of the unusual immunophenotype and FLT3-ITD mutation illustrates the plasticity of the hematopoietic stem cell and the pathobiology of leukemia with mixed lineage or lineage infidelity.

Myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) are hematological malignancies characterized by simultaneous presence of both myelodysplastic and myeloproliferative features [1]. C...

Background: Dehydrated hereditary stomatocytosis (DHSt), also known as hereditary xerocytosis, is a rare congenital hemolytic anemia with an autosomal dominant inheritance. It is often misdiagnosed for other hemolytic conditions, such as hereditary spherocytosis. Herein, we present the case of a young female presenting with hemolytic anemia, who was found to have a mutation in PIEZO1 gene and was subsequently diagnosed with DHSt. Case Presentation: A 39-year-old woman of Asian origin presented to the hematology clinic for evaluation of anemia diagnosed on blood work performed by primary care physician for symptoms of fatigue. She was adopted and had no information about her family history. A complete blood count revealed: hemoglobin 8.2 g/dL, mean corpuscular volume (MCV) 121.6 fL, absolute retic counts 0.08 M/mcL, lactate dehydrogenase 851 units/L and a negative coombs test. Iron profile revealed iron saturation 85% and ferritin 1961.4 ng/mL (see table 1 for laboratory work up). The peripheral blood smear showed anisopoikilocytosis, macrocytes, spherocytes and several stomatocytes along with polychromatophils. An ultrasound of the abdomen was subsequently performed, and which revealed hepatomegaly and biliary stones. Enzyme assay for glucose-6-phosphate dehydrogenase and flow cytometry for paroxysmal nocturnal hemoglobinuria were also sent and were negative. Red blood cells osmotic fragility was decreased. The bone marrow biopsy showed full spectrum trilineage hematopoiesis with no mutations on molecular testing. Based on the blood smear and clinical presentation, a diagnosis of DHSt was suspected. Genetic testing was performed and which revealed Sc.2842C>T; p.Arg948Cys mutation in the PIEZO1 gene by massively parallel sequencing and confirmation by Sanger sequencing. This confirmed the diagnosis of DHSt. Patient was started on high dose folic acid with improvement in her hemoglobin in one month. She did not require any blood transfusions. MRI liver T2* scan measured quantitative liver iron of 31 mM/g, which was at the high normal range. Discussion: DHSt is caused by gain of function mutation in PIEZO1 gene or KCCN4 gene which encode the transmembrane cation ion channel and Gardo's channel respectively on red blood cell membrane. This results in delayed inactivation of the channel. The disease presents as a spectrum from asymptomatic anemia to massive hemolysis, and many patients present later in life. Patients may manifest clinical signs of jaundice, pallor, fatigue, splenomegaly, gallstones and iron overload. Labs are typically significant for elevation in mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW) and MCV, with classic slit cells red blood cells seen on peripheral blood smear (see image 1). PIEZO1 is expressed early in erythroid progenitor cells and may delay erythroid differentiation and reticulocyte maturation, which may be the cause of low reticulocyte count such as in our patient. While treatment is supportive with blood transfusions, only a minority of DHSt patients ever require regular transfusions. Interestingly, hyperferritinemia, high transferrin saturation or clinical iron overload are quite frequent in DHSt and iron chelation is recommended. Splenectomy is contraindicated due to increased risk of thrombosis. Conclusions: DHSt as a rare inherited hemolytic anemia and its diagnosis warrants maintaining a high index of clinical suspicion based on supportive laboratory findings. Diagnosis involves thorough testing earlier in the disease as patients may be asymptomatic until adulthood. Delaying the diagnosis may lead to severe iron overload and consequent organ damage. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Depletion of glutamine (Gln) has emerged as a potential therapeutic approach in the treatment of acute myeloid leukemia (AML), as neoplastic cells require Gln for synthesis of cellular components essential for survival. Asparaginases deplete Gln, and asparaginase derived from Erwinia chrysanthemi (Erwinaze) appears to have the greatest glutaminase activity of the available asparaginases. In this Phase I study, we sought to determine the dose of Erwinaze that safely and effectively depletes plasma Gln levels to ≤ 120 μmol/L in patients with relapsed or refractory (R/R) AML. Five patients were enrolled before the study was halted due to issues with Erwinaze manufacturing supply. All patients received Erwinaze at a dose of 25,000 IU/m2 intravenously three times weekly for 2 weeks. Median trough plasma Gln level at 48 h after initial Erwinaze administration was 27.6 μmol/L, and 80% (lower limit of 1-sided 95% CI 34%) of patients achieved at least one undetectable plasma Gln value (

Programmed death 1 (PD-1) receptor and its ligand (PD-L1) facilitate immune evasion in multiple myeloma (MM). We hypothesized that pembrolizumab, PD-1-antibody, can enhance antimyeloma cellular immunity generated by pomalidomide, leading to improved clinical responses. In this single-center, phase 2 study, 48 patients with relapsed/refractory MM (RRMM) received 28-day cycles of pembrolizumab, 200 mg IV every 2 weeks, pomalidomide 4 mg daily for 21 days, and dexamethasone 40 mg weekly. Patients had a median of 3 (range: 2-5) lines of therapy, median age 64 (range: 35-83) years, and had received both an immune modulatory drug (IMiD) and proteasome inhibitor: (35 [73%] of 48) were refractory to both; (31 [70%]) had received an autologous transplant, and (30 [62%]) had high-risk cytogenetics. Adverse events grade 3 to 4 occurred in (19 [40%] of 48 patients), including hematologic toxicities (19 [40%]), hyperglycemia (12 [25%]), and pneumonia (7 [15%]). Autoimmune events included pneumonitis (6 [13%]) and hypothyroidism (5 [10%]), mostly ≤ grade 2. Objective responses occurred in (29 [60%] of 48) patients, including stringent complete response/complete response (4 [8%]), very good partial response (9 [19%]), and partial response (16 [33%]); median duration of response was 14.7 months. At median follow-up of 15.6 months, progression-free survival (PFS) was 17.4 months and overall survival was not reached. Analyses of pretreatment marrow samples revealed a trend for increased expression of PD-L1 in responding patients and longer PFS with increased T-lymphocyte infiltrates, irrespective of PD-1 expression. Pembrolizumab, pomalidomide, and low-dose dexamethasone have acceptable safety and durable responses in RRMM patients. This trial was registered at www.clincialtrials.gov as #NCT02289222.

Background: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder with features of both myeloproliferative neoplasm and myelodysplastic syndrome (MDS). CMML is characterized by persistent blood monocytosis >1 x 109/L, bone marrow dysplasia in one or more hematopoietic cell lines, and increased risk of transformation to acute myeloid leukemia (AML). Our review of SEER Medicare data (Haematologica 2013;98:584) demonstrated that, compared to MDS, CMML has shorter overall survival (OS) and more frequent progression to AML. Hypomethylating agents (HMAs) have become standard therapy for CMML, with reported response rates of 37-69%, but their impact on AML transformation and OS is unclear. Methods: We retrospectively reviewed CMML patients treated at the University of Maryland Greenebaum Comprehensive Cancer Center between January 2000 and December 2019. Clinical characteristics, treatments, AML progression, time to AML progression (TTP), and OS were recorded and analyzed. Descriptive statistics were used for baseline characteristics and Kaplan-Meier analysis was performed for time-to-event data. Statistical analyses were performed using GraphPad Prism 8®. Results: We identified 71 patients with CMML, 82% male and 73% white, with a median age of 69 (range 25 - 96) years; 51% had Forty-six patients received HMAs, with an overall response rate (ORR) of 54% (complete response or partial response), while 25 patients did not receive HMAs. Patient and disease characteristics were similar in HMA- and non-HMA-treated patients (Table 1). The estimated OS of HMA-treated patients was 20 months, compared to 14 months for non-HMA-treated patients (p =0.43) (Figure 1). AML transformation occurred in 52% of patients treated with HMAs, with TTP ranging from 3 to 65 months, and in 33% patients not treated with HMAs, with TTP ranging from 5 to 47 months. Most patients receiving HMAs (63%) received ≥ 6 cycles; 46% transformed to AML despite initial response, often in a sudden and unpredictable manner. HMAs were azacitidine in 13 patients, decitabine in 24, azacitidine followed by decitabine in 4, and decitabine followed by azacitidine in 5. Five CMML patients in our cohort underwent allogenic stem cell transplantation. Four of the five relapsed with transformation to AML post transplant, and only one patient remains in remission, 9 months post transplant. Conclusions: Despite a 54% ORR, HMA treatment did not have a significant impact on frequency of AML transformation, or OS in our cohort. Based on our data, favorable response rates previously reported with HMAs and also seen in our patients do not appear to translate into decreased frequency of AML transformation or prolonged OS. Though our study is a retrospective study with inherent selection bias, our results underscore the ongoing need for novel therapies and for clinical trials for CMML patients. Disclosures Niyongere: Kartos Therapeutics: Other: Received clinical trial research support with Kartos Therapeutics ; Forty Seven: Other: Received clinical trial research support with Forty Seven. Emadi:Amgen: Membership on an entity's Board of Directors or advisory committees; KinaRx: Other: co-founder and scientific advisor; NewLink Genetics: Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Research Funding. Doung:Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial research support; Incyte: Other: clinical trial research support; Astex: Other: clinical trial research support; MedPacto: Other: clinical trial research support. Baer:Takeda: Other: Institutional research funding; Oscotec: Other: Institutional research funding; Kite: Other: Institutional research funding; Incyte: Other: Institutional research funding; Forma: Other: Institutional research funding; Astellas: Other: Institutional research funding; AbbVie: Other: Institutional research funding.

The day 14 bone marrow aspirate and biopsy (D14BM) is regularly used to predict achievement of complete remission (CR) with induction chemotherapy in acute myeloid leukemia (AML), however its utility has been questioned. Clearance of peripheral blood blasts (PBB) may serve as an early measure of chemosensitivity. PBB rate of clearance (PBB-RC) was calculated for treatment-naive AML patients (n = 164) undergoing induction with an anthracycline and cytarabine (7+3) and with detectable PBB at diagnosis. PBB-RC was defined as the percentage of the absolute PBB count on the day of diagnosis that was cleared with each day of therapy, on average, until D14 or day of PBB clearance. Each 5% increase in PBB-RC approximately doubled the likelihood of D14BM clearance (OR = 1·81; 95% CI: 1·24-2·64, P < 0·005). PBB-RC was also associated with improved CR rates (OR per 5% = 1·97; 95% CI: 1·27-3·01, P < 0·005) and overall survival (OS) [hazard ratio (HR) per 5% = 0·67; 95% CI: 0·52-0·87]. African American patients had poorer OS adjusted for PBB-RC (HR = 2·18; 95% CI: 1·13-4·23), while race was not associated with D14BM or CR rate. PBB-RC during induction chemotherapy is predictive of D14BM clearance, CR, and OS, and can therefore serve as a prognostic marker for clinical outcomes in AML.

Supplemental_material for The Performance of Diagnostic Criteria for Hemophagocytic Lymphohistiocytosis in Critically Ill Patients by Nikhil K. Meena, Odai Sinokrot, Abhijit Duggal, Daisy Alpat, Zeba N. Singh, Jean M. Coviello, Manshi Li, Xiaofeng Wang, and Eduardo Mireles-Cabodevila in Journal of Intensive Care Medicine

Myeloid sarcoma (MS) is a rare extramedullary presentation of myeloid malignancies, most commonly seen in association with acute myeloid leukemia (AML). Although MS can develop in any organ, the involvement of the hepatobiliary system is rare. With clinical manifestations of jaundice, abdominal pain and other gastrointestinal symptoms, MS presenting at this location can be a challenge to diagnose, particularly in patients with no known history of hematologic malignancy. This may cause delay in proper management. Here we report 3 cases from a single institution and a review of the literature concerning the epidemiology, clinical presentation, treatment and outcomes in patients with MS of the liver, biliary tree and pancreas.

Adults with relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) treated with conventional chemotherapy have dismal outcomes. Novel immunotherapies targeting CD19, including the bispecific T-cell engager blinatumomab and chimeric antigen-receptor T (CAR-T) cells, have revolutionized the treatment of R/R B-ALL. Robust response rates to CAR-T cell therapy after blinatumomab have recently been reported, but it is unknown whether blinatumomab can be effective following failure of anti-CD19 CAR-T cell therapy. Herein, we describe a patient with Philadelphia chromosome-positive B-ALL who relapsed after CD19-directed CAR-T therapy, but subsequently responded to the combination of blinatumomab and the tyrosine kinase inhibitor ponatinib, with the achievement of a complete remission lasting 12 months.

Key Clinical Message Assiduous surveillance for genetic aberrations is necessary in patients on cytotoxic therapies to detect therapy-related myeloid neoplasms (t-MN). Current modalities include metaphase cytogenetics and FISH. Since t-MN may develop abruptly in cytogenetically normal patients, a discussion exploring additional methods such as SNP-array and targeted-deep-sequencing to detect subchromosomal abnormalities is needed.

BACKGROUND: Crenolanib (crenolanib besylate, 4-piperidinamine, 1-[2-[5-[(3-methyl-3-oxetanyl)methoxy]-1H-benzimidazol-1-yl]-8-quinolinyl]-, monobenzenesulfonate) is a potent and specific type I inhibitor of fms-like tyrosine kinase 3 (FLT3) that targets the active kinase conformation and is effective against FLT3 with internal tandem duplication (ITD) with point mutations induced by, and conferring resistance to, type II FLT3 inhibitors in acute myeloid leukemia (AML) cells. Crenolanib is also an inhibitor of platelet-derived growth factor receptor alpha and beta and is in clinical trials in both gastrointestinal stromal tumors and gliomas. METHODS: We tested crenolanib interactions with the multidrug resistance-associated ATP-binding cassette proteins ABCB1 (P-glycoprotein), ABCG2 (breast cancer resistance protein) and ABCC1 (multidrug resistance-associated protein 1), which are expressed on AML cells and other cancer cells and are important components of the blood-brain barrier. RESULTS: We found that crenolanib is a substrate of ABCB1, as evidenced by approximate five-fold resistance of ABCB1-overexpressing cells to crenolanib, reversal of this resistance by the ABCB1-specific inhibitor PSC-833 and stimulation of ABCB1 ATPase activity by crenolanib. In contrast, crenolanib was not a substrate of ABCG2 or ABCC1. Additionally, it did not inhibit substrate transport by ABCB1, ABCG2 or ABCC1, at pharmacologically relevant concentrations. Finally, incubation of the FLT3-ITD AML cell lines MV4-11 and MOLM-14 with crenolanib at a pharmacologically relevant concentration of 500 nM did not induce upregulation of ABCB1 cell surface expression. CONCLUSIONS: Thus ABCB1 expression confers resistance to crenolanib and likely limits crenolanib penetration of the central nervous system, but crenolanib at therapeutic concentrations should not alter cellular exposure to ABC protein substrate chemotherapy drugs.

Durable remission with salvage decitabine and donor lymphocyte infusion (DLI) for relapsed early T-cell precursor ALL

We report a NUMA1-PDGFRB fusion in a myeloproliferative neoplasm with eosinophilia in a 61-year old man, with response to imatinib mesylate therapy. A t(5;11) chromosome translocation involving bands 5q32 and 11q13.4 was identified by metaphase chromosome analysis, and rearrangement of the platelet-derived growth factor receptor beta (PDGFRB) gene on 5q32 was demonstrated by FISH using a PDGFRB break-apart probe set. Bacterial artificial chromosome (BAC) FISH mapping of the PDGFRB fusion partner gene narrowed the breakpoint at 11q13.4 to a 150 kb genomic region containing three genes, including NUMA1. Mate pair sequencing analysis demonstrated NUMA1-PDGFRB fusion. The fusion protein includes coiled-coil domains of nuclear mitotic apparatus protein 1 (NuMA1, involved in protein homodimerization and heteroassociation) and tyrosine kinase domains of PDGFRB. Diverse rearrangements involving the PDGFRB gene have been identified in myeloid and lymphoid neoplasms with eosinophilia, but rearrangement of the nuclear mitotic apparatus protein 1 (NUMA1) gene has previously been reported in a human malignancy in only one instance, a NUMA1-RARA fusion caused by a t(11;17) translocation in a patient with acute promyelocytic leukemia. The NUMA1-PDGFRB fusion is the second instance of rearrangement of NUMA1, encoding an element of the mitotic apparatus, in human cancer.

Objective The presentation of CD30+ lymphoproliferative disorder can pose a diagnostic challenge, as CD30 expression has been observed in various reactive, inflammatory and neoplastic diseases. In this study we described two case reports with the immunohistochemical (IHC) profile of TLPD and ruled out TLPD mimics such as anaplastic large cell lymphoma. Findings Case 1: A 90-year-old female presented with a 6-month history of 3 × 5 mm ulceration of the left ventro-lateral tongue. Case 2: A 52-year-old female presented with a 15 × 20 mm deep submucosal mass of the left dorsum tongue. Histopathologic examination in both cases revealed infiltrate of atypical lymphocytes with some showing mitotic figures, mixed with eosinophils that penetrated deep into the muscle layers. The IHC profile revealed positivity for CD3 and CD2. CD30 was also positive in almost 75% of the atypical infiltrating cells. CD1a, EMA, ALK-1 and GRANZB were negative. Case 2 showed scattered positivity for CD20, and more of plasma cells with non-restricted positivity for Kappa and Lambda. In concert with hematopathology, both cases were reviewed and a diagnosis of TLPD was favored due to the increased strong diffuse positivity for CD30, negative expression of ALK-1 and CD1a, and the lack of trauma history. Conclusion As TLPD is managed clinically similar to Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) and follows an indolent course, it is important to recognize these entities to avoid possible overtreatment from a misdiagnosis of anaplastic large cell lymphoma.

Introduction: CD19 is a transmembrane protein restricted to B-lineage cells and follicular dendritic cells. In conjunction with CD21, CD81, and CD225, CD19 acts as a B cell co-receptor to decrease the threshold for antigen receptor-dependent stimulation. CD19 trafficking and expression are orchestrated by a multitude of molecules. Resistance to blinatumomab (Blina, anti-CD19 therapy) in acute lymphoblastic leukemia (ALL) is thought to be due in part to the emergence of CD19-negative escape variants. Loss of expression of CD81 and/or CD21, which are required for CD19 trafficking, results in the lack of CD19 expression. In addition, alternative CD19 splicing and other non-CD19-mediated resistance mechanisms have been described. Therefore, we aimed to study CD19 trafficking and response to Blina in ALL patients. Methods: Peripheral blood was collected at our Center. Mononuclear cells (PBMCs) were isolated and viably frozen. Cells were then thawed and washed with PBS with 10% FBS, and viable cells were counted using trypan blue dye exclusion. 1x10^6 cells/test were stained for CD19, CD81 (BD Biosciences, San Jose, CA) and CD21 (Biolegend, San Diego, CA). After incubation, cells were washed 2x with FACs buffer, resuspended and acquired on a BD Canto II flow cytometer. Results: Blood was obtained from 10 patients with relapsed or refractory pre-B-ALL with blood blasts prior to Blina treatment. Five patients subsequently achieved complete remission (CR). Cells from four of these patients had CD21 expression on 40% of cells. Of the 5 patients whose disease did not respond to Blina, four also had CD21 expression on 40% of cells in all samples. Conclusion: Although CD21 and CD81 are required for CD19 trafficking and expression, loss of either of these antigens measured by flow cytometry did not correlate with the response to Blina. PatientAge(years)DiagnosisKaryotypeCD19*CD21*CD81*Response to Blinatumomab176Pre-B-ALL46,XX,t(9;22)(q34.1;q11.2)53241Yes (CR)255Pre-B-ALL46, X,inv(Y)(p11.2q11.23), dic(9;12)(p13;p13), del20(q11.2)42146Yes (CR)347Pre-B-ALL46, XX,t(4;11)(q21;q23)941256Yes (CR)484Pre-B-ALL46,XX,i(9)Iq10)65372Yes (CR)551Pre-B-ALL46, XX, t(9;22)(q34.1;q11.2)77578Yes (CR)633Pre-B-ALL46, XY, +X, der(17;18)(q10;q10)67185No725Pre-B-ALL46, XY, der(20;21)(q10;q10),+2146432No825Pre-B-ALL46, Y, t(X;4)(p11.2;p15), der(9)t(9;14)(p21;q12) del(9)(p21),del(14)q13), +mar[cp14]742429No979Pre-B-ALL46, XY48123No1073Pre-B-ALL46, XY59129No*% cells; CR = complete remission Note: This abstract was not presented at the meeting. Citation Format: Firas El Chaer, Brandon Carter-Cooper, Rena G. Lapidus, Maria R. Baer, Zeba N. Singh, Ashkan Emadi. Anti-CD19 therapy for precursor B-acute lymphoblastic leukemia: Response and resistance mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 542.

Poly (ADP-ribose) polymerase inhibitors (PARPis) are clinically effective predominantly for BRCA-mutant tumors. We introduce a mechanism-based strategy to enhance PARPi efficacy based on DNA damage-related binding between DNA methyltransferases (DNMTs) and PARP1. In acute myeloid leukemia (AML) and breast cancer cells, DNMT inhibitors (DNMTis) alone covalently bind DNMTs into DNA and increase PARP1 tightly bound into chromatin. Low doses of DNMTis plus PARPis, versus each drug alone, increase PARPi efficacy, increasing amplitude and retention of PARP1 directly at laser-induced DNA damage sites. This correlates with increased DNA damage, synergistic tumor cytotoxicity, blunting of self-renewal, and strong anti-tumor responses, in vivo in unfavorable AML subtypes and BRCA wild-type breast cancer cells. Our combinatorial approach introduces a strategy to enhance efficacy of PARPis in treating cancer.

Major clinical response to nivolumab in relapsed/refractory Hodgkin lymphoma after allogeneic stem cell transplantation

Chronic myelomonocytic leukemia (CMML) consists of disorders with overlapping dysplastic and proliferative features. The diagnosis of CMML requires absolute monocytosis (> 1000/μL) in addition to other criteria outlined by the World Health Organization (WHO) classification.(1) Monocytosis not reaching 1000/μL has been observed in myelodysplastic syndrome (MDS) and presents a diagnostic challenge in classification especially if increases in leukocyte count occurring during disease shifts the monocyte count into the absolute range. We discuss the laboratory and clinical features of 3 patients with myelodysplasia and associated monocytosis. Absolute neutropenia was the dominant feature at presentation, with mild anemia, thrombocytopenia, monocytosis (as a percentage), multilineage dysplasia, and increased myeloblasts, consistent with a diagnosis of refractory anemia with excess blasts (RAEB). Absolute monocytosis fulfilling the diagnostic criteria for CMML developed over 6-8 months, prompting a change in diagnosis. Two of 3 patients had normal cytogenetic examinations. JAK2 V617F mutation was detected after transformation to CMML in 1 of them; in the other, a novel translocation t(5;12)(p13;q24) was observed at the time of progression to acute leukemia. The use of different diagnostic terminologies--MDS, dysplasia with reactive monocytosis, myeloproliferative, and myeloproliferative/myelodysplastic syndromes by different and even the same pathologists at different times created confusion among the clinicians and patients. The disease course in these 3 patients was characterized by better survival and prolonged time to progression to acute leukemia, than predicted based on the original diagnosis of RAEB, suggesting that MDS with monocytosis may represent a subgroup distinct from MDS or CMML.

Background Successful allogeneic stem cell transplantation (HSCT) in treatment of patients (pts) with acute myeloid leukemia (AML) is dependent upon graft-versus-leukemia, suggesting that intact immune surveillance is essential for eradicating minimal residual disease. Myeloblast-induced T-cell tolerance through overexpression of indoleamine 2,3-dioxygenase (IDO) is thought to play a significant role in immune evasion through upregulation of tryptophan (Trp) catabolism and kynurenine production, resulting in a Trp-poor environment that leads to immune system suppression. Indoximod is a small-molecule inhibitor of the IDO pathway that acts directly on immune cells to reverse IDO pathway-mediated suppression. We are assessing the safety and preliminary efficacy of indoximod in combination with standard induction chemotherapy in patients (pts) with newly diagnosed AML. Methods In this open-label, multicenter, phase 1 study (NCT02835729), eligible pts with newly diagnosed AML were treated with indoximod in combination with induction chemotherapy (idarubicin 12 mg/m2/d x3 days with cytarabine 100 mg/m2/d x7 days). Using a "3+3" design, indoximod (600 mg [dose level 0], 1000 mg [dose level 1], 1200 mg [dose level 2]) was given orally every 8 hours (Q8h) starting on day 9 of induction. Regimen limiting toxicity (RLT) was defined as any ≥ grade 3 non-hematologic adverse event (AE) that was not incontrovertibly related to the underlying AML or cytarabine or idarubicin. After induction, pts received up to 4 cycles of high dose cytarabine (HiDAC) consolidation while continuing indoximod. Patients continued on maintenance indoximod for up to 6 months from completion of consolidation therapy. Indoximod was discontinued 4 weeks prior to HSCT in eligible patients and not restarted as maintenance post-HSCT. Results As of July 15, 2018, 31 pts were enrolled (median age 55 years, range 18-78; 77% male). Six patients did not proceed with study therapy due to a diagnosis of acute promyelocytic leukemia, issues with medical insurance coverage, consent withdrawal, critical illness, and intestinal myeloid sarcoma preventing oral intake. Pts who received ≥1 dose of indoximod were included in the intention-to-treat (ITT) analysis (n=25), and pts who received ≥80% of their scheduled indoximod doses were included in the per-protocol (PP) analysis (n=19). Reasons for not completing ≥80% of indoximod doses were: consent withdrawal (n=3), inability to swallow (n=2) and physician decision (n=1). Of the 19 PP patients, 16 (84%) had either unfavorable karyotype or adverse mutation profile and 3 (16%) had secondary AML (s-AML). Indoximod combined with induction chemotherapy was well tolerated; no RLT was observed. The most frequent grade ≥3 non-hematologic treatment-emergent AEs in the ITT population, regardless of attribution, were febrile neutropenia (60%), hypoxia (16%), atrial fibrillation (12%), pneumonia (12%), hypocalcemia (12%), and hypotension (12%). Among 25 ITT pts, 21 (84%) achieved a remission (CR/CRh/CRi/CRp), and 15 of 19 (79%) in the PP analysis achieved remission. Among 12 pts with measurable residual disease (MRD) available in remission, 10 (83%) had MRD Conclusions Indoximod is well tolerated in combination with standard AML induction therapy. Rates of morphologic response and of MRD-neg status are very promising. The recommended phase 2 dose (RP2D) was 1200 mg oral Q8h and a placebo-controlled randomized phase 2 study is under development. Disclosures Emadi: NewLink Genetics: Research Funding. Loken:Hematologics, Inc: Employment, Equity Ownership. Kennedy:NewLink Genetics: Employment, Equity Ownership. Link:NewLink Genetics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Munn:NewLink Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background: Acute leukemias of ambiguous lineage (ALAL), including acute undifferentiated leukemia and mixed phenotype acute leukemia (MPAL), are rare hematologic malignancies, accounting for only 2-5% of cases of acute leukemia. Outcomes are generally poor, and retrospective studies have suggested that patients have better outcomes when treated with regimens used for acute lymphoblastic leukemia (ALL) rather than acute myeloid leukemia (AML). Due to heterogeneous definitions and rarity of these leukemias, no single ALL regimen has been studied extensively. Hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyperCVAD) is one of the most widely used adult ALL regimens in the United States. We retrospectively examined the effectiveness of this regimen as initial therapy in patients with ALAL. Methods: We retrospectively reviewed records from adult patients treated initially with hyperCVAD-based chemotherapy for ALAL as defined by the World Health Organization at five academic institutions. Only patients whose diagnosis was verified at a participating institution were examined. Philadelphia (Ph) chromosome-positive ALAL patients treated concurrently with tyrosine kinase inhibitors were included. The primary objective of the study was to determine the overall response rate (ORR) and median overall survival (OS). Descriptive statistics were used for baseline characteristics and responses, and Kaplan-Meier estimates were used to calculate all time-to-event outcomes. Results: Twenty-two patients were identified, and pre-treatment characteristics are shown in the Table. Median age was 50 years (range, 22-69), with an even distribution of male and female patients (50% each). The majority (77%) were Caucasian. Two patients (9%) had acute undifferentiated leukemia, 11 (50%) T/myeloid MPAL, 8 (36%) B/myeloid MPAL, and 1 (5%) B/T MPAL. Seven (32%) had a complex karyotype (at least 3 abnormalities), 6 (27%) had a normal karyotype, 3 (14%) were Ph-positive and were treated concurrently with dasatinib, and 1 (5%) had an 11q23 rearrangement. FLT3-ITD was detected in 5 of 8 patients (63%) with an available mutation panel. Three (15%) had central nervous system (CNS) involvement at presentation, and one additional patient developed CNS disease during the course of therapy. There were no deaths within the first 30 days, and the median number of cycles given was 4 (range, 1-8). The CR rate was 73% (n=16) and an additional 14% (n=3) had CR with incomplete count recovery (CRi), for an ORR rate of 86%. One patient had a partial response, and 2 patients had no response. Of the 19 patients achieving CR or CRi, median number of cycles to CR was 1.5, and 12 (63%) proceeded to allogeneic hematopoietic stem cell transplantation (alloHSCT). Of the 7 responders who did not receive alloHSCT, 3 relapsed shortly after initial CR and 4 are alive and in remission 77, 39, 37 and 10 months from treatment initiation. All 3 patients with Ph-positive disease achieved CR. Only 1 proceeded with alloHSCT and all 3 patients are alive and in remission at 51, 39, and 10 months. With a median follow up of 37 months, 14 (64%) patients were alive and in remission, including 11 who had undergone alloHSCT. Four of the 6 patients who died had a complex karyotype. Median overall survival for the entire cohort was not reached (Figure). Conclusions: HyperCVAD results in high remission rates in patients with ALAL, with low incidence of early mortality and high ability to proceed to allogeneic transplantation following response. HyperCVAD can be considered an effective front-line therapy for patients with ALAL. Additionally, hyperCVAD may be a backbone for incorporation of novel immunotherapies and targeted therapies, which may improve results in patients with appropriate targets. Disclosures Sweet: Astellas: Consultancy; Agios: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Jazz: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Agios: Consultancy; Celgene: Honoraria, Speakers Bureau; BMS: Honoraria; Phizer: Consultancy; Jazz: Speakers Bureau; Astellas: Consultancy; Phizer: Consultancy; BMS: Honoraria. Wang:Novartis: Speakers Bureau; Amgen: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Speakers Bureau; Novartis: Speakers Bureau; Jazz: Speakers Bureau; Amgen: Consultancy. Al-Kali:Novartis: Research Funding.

In practice, cases of therapy-related myelodysplastic syndrome (t-MDS) are often classified according to morphologic schemes used for de novo MDS. However, there are few data addressing the appropriateness of such classification. We studied 155 patients with therapy-related acute myeloid leukemia (t-AML)/t-MDS to determine whether subclassification by the World Health Organization (WHO) criteria for de novo MDS provides prognostic information in t-MDS. In addition, we assessed whether cytogenetic stratification by the International Prognostic Scoring System (IPSS) guidelines or karyotypic complexity was prognostically important. We found no differences in median survival times among patients classified into the different WHO subgroup of MDS or according to their bone marrow blast percentage; our results indicate a uniformly poor outcome in t-MDS regardless of morphologic classification. However, significant survival differences correlated with cytogenetic stratification according to IPSS guidelines and/or karyotypic complexity. We found only a borderline difference in median survival of patients with an initial t-MDS diagnosis compared with patients with an initial t-AML diagnosis.

Differentiation of hematopoietic stem-progenitor cells (HSPCs) into mature blood lineages results from the translation of extracellular signals into changes in the expression levels of transcription factors controlling cell fate decisions. Multiple transcription factor families are known to be involved in hematopoiesis. Although the T-box transcription factor family is known to be involved in the differentiation of multiple tissues, and expression of T-bet, a T-box family transcription factor, has been observed in HSPCs, T-box family transcription factors do not have a described role in HSPC differentiation. In the current study, we address the functional consequences of T-bet expression in mouse HSPCs. T-bet protein levels differed among HSPC subsets, with highest levels observed in megakaryo-erythroid progenitor cells (MEPs), the common precursor to megakaryocytes and erythrocytes. HSPCs from T-bet-deficient mice exhibited a defect in megakaryocytic differentiation when cultured in the presence of thrombopoietin. In contrast, erythroid differentiation in culture in the presence of erythropoietin was not substantially altered in T-bet-deficient HSPCs. Differences observed with respect to megakaryocyte number and maturity, as assessed by level of expression of CD41 and CD61, and megakaryocyte ploidy, in T-bet-deficient HSPCs were not associated with altered proliferation or survival in culture. Gene expression micro-array analysis of MEPs from T-bet-deficient mice exhibited diminished expression of multiple genes associated with the megakaryocyte lineage. These data advance our understanding of the transcriptional regulation of megakaryopoiesis by supporting a new role for T-bet in the differentiation of MEPs into megakaryocytes.

Hypopigmented mycosis fungoides is an uncommon clinical variant of cutaneous T-cell lymphoma. We hypothesized that hypomelanosis in hypopigmented mycosis fungoides may have a similar mechanism as in vitiligo, a condition in which it is believed that alterations in expression of CD117 (stem cell factor receptor/KIT protein) on epidermal melanocytes and abnormal interactions between melanocytes and surrounding keratinocytes may play a pathogenic role. To test the hypothesis that similar mechanisms might also explain hypopigmentation in hypopigmented mycosis fungoides, skin specimens from five cases each of hypopigmented mycosis fungoides and vitiligo were studied immunohistochemically for immunophenotype of the infiltrating cells, CD117 (expressed by epidermal melanocytes), and pan melanoma cocktail of antigens (gp100, tyrosinase, and MART-1) expression; cases of conventional mycosis fungoides and normal skin were studied in parallel as controls. Our findings confirm a predominance of CD8+ neoplastic T cells in hypopigmented mycosis fungoides. Similarly, the epidermal lymphocytic infiltrate in vitiligo was also composed of CD8+ cytotoxic T cells, in contrast to an epidermal infiltrate composed of CD4+ T cells in conventional mycosis fungoides. The average number of epidermal CD117 expressing cells followed the same pattern of decreased expression in hypopigmented mycosis fungoides as in vitiligo, whereas the levels in conventional mycosis fungoides were higher, and similar to that observed in normal skin. Furthermore, a decreased number of melanocytes per high-power field of the length of the biopsy was present in hypopigmented mycosis fungoides and vitiligo, as compared with either conventional mycosis fungoides or normal skin, suggesting a correlation between decreased expression of CD117 and decreased number of melanocytes. We propose that decreased expression of CD117 and its downstream events in melanocytes may be initiated by cytotoxic effects of melanosomal-antigen-specific CD8+ neoplastic T lymphocytes, resulting in destabilization of CD117 and leading to dysfunction and/or loss of melanocytes in the epidermis of hypopigmented mycosis fungoides.

Marizomib, a natural marine product, is an irreversible proteasome inhibitor (PI) that has distinct advantages over the currently approved PIs in that it irreversibly inhibits all three enzymatic activities of the proteasome and has been demonstrated to cross the blood brain barrier. Several studies have demonstrated that marizomib (MRZ) penetrates and can be retained in the CNS and that it substantially inhibits proteasome activity in the brain; radiolabeled MRZ showed 30% CNS biodistribution compared with blood levels in rats; it elicits a significant anti-tumor effect in a rodent model of malignant glioma; and pharmacological inhibition of proteasome activity has been observed in primate brains. MRZ is currently under clinical investigation in relapsed-refractory multiple myeloma and grade IV malignant glioma. CNS-multiple myeloma (MM) is a rare manifestation of extra-medullary disease with very limited therapeutic options. Its prevalence is increasing as anti-myeloma therapies become more effective at treating systemic disease, resulting in the CNS becoming a sanctuary site for the disease further highlighting the urgent unmet clinical need in this patient population. MRZ has demonstrated encouraging activity in non-CNS-MM, and has emerging clinical activity in glioma making it a potentially promising CNS-MM therapeutic intervention. To date 3 patients have been treated under compassionate use protocol with MRZ for CNS-involved MM. Two of these patients have received sufficient doses of MRZ in combination with DEX to evaluate its activity in this indication. MRZ was dosed initially at 0.5mg/m2 and then increased to 0.7mg/m2once tolerability had been established on the schedule currently in use on the glioma study (days 1, 8, and 15 of a 28 day cycle as a 10 minute infusion). Both patients, who had received prior cranio-spinal radiotherapy and intrathecal chemotherapy with no response, have tolerated MRZ well with no unexpected adverse events. The first patient had an 89% reduction in cerebrospinal fluid (CSF) plasmacytosis and 77% serum LDH reduction. After 5 months daratumumab was added to MRZ and further clinical improvement was observed (resolution of double vision and becoming fully ambulatory). Six months after MRZ initiation the patient progressed clinically and stopped treatment. Clinical symptoms disappeared in the second patient in the second month of MRZ with complete resolution of CSF plasmacytosis and CSF monoclonal spike. The patient is currently undergoing the 4th cycle of treatment with sustained resolution of saddle anesthesia and no further signs of cauda equina symptoms. Collectively, these cases provide preliminary evidence that MRZ may have utility as a therapeutic for CNS-MM and also demonstrate that combination of MRZ and daratumumab may provide benefit in this indication. Follow up is ongoing on the second patient and more mature data will be presented on this patient and any additional patients subsequently treated under compassionate use for CNS-MM. Disclosures MacLaren: Triphase Accelerator: Employment, Equity Ownership. Richardson:Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Trikha:Encycle Therapeutics: Consultancy, Equity Ownership; Triphase Accelerator: Employment, Equity Ownership. Parameswaran:Takeda: Consultancy.

BACKGROUND: Immunotherapy in MM is emerging as an effective modality in therapy of MM with the approval of several monoclonal antibodies and encouraging results for vaccines and T cell therapy. Programmed death 1 (PD-1) receptor and its ligand (PD-L1) is one mechanism of immune evasion by MM to suppress T cell function. In this trial, we hypothesized that pembrolizumab, a PD-1-blocking antibody, would enhance immune modulatory properties of pomalidomide in RRMM pts. METHODS: In this single center, phase II study, 48 patients with RRMM received 28-day cycles of pembrolizumab (at a dose of 200 mg IV) every 2 weeks (in a run in phase, first 6 patients received 200 mg IV every 4 weeks) plus pomalidomide (4 mg daily x 21 days) and dexamethasone 40 mg weekly. Study objectives were measurements of safety & efficacy and correlation of the CD3/PD-1 on T cells and PD-L1 on plasma cells with response. RESULTS: The median age was 64 years (range: 35-82); 38% were black and 65% were men, Patients had a median of 3 lines of prior therapy (range: 2-6); All patients had received both IMids and Proteosome inhibitors; 70% had prior auto-SCT. 80% were double refractory to both IMids (lenalidomide) and Proteosome inhibitors [bortezomib (n=18) or carfilzomib (n=20)] and an additional 20% were refractory to lenalidomide. The median time from MM diagnosis to study entry was 4 years (range: 1-25). Most common cytogenetic abnormalities were 1q+ (60%), hyperdiploidy (15%) and high-risk FISH [del 17p, t(4:14) and/or t(14:16)] in 38%. Six patients had soft tissue extramedullary plasmacytomas. There were no infusion-related reactions. Hematologic toxicities (≥ grade 3) were anemia (21%), neutropenia (40%), lymphopenia (15%) and thrombocytopenia (8%). Non-hematologic events Grade ≥3 were fatigue (15%), hyperglycemia (25%), upper respiratory tract infections (21%), rash (10%); and most frequent grade ≥2 were dyspnea (54%), dizziness (44%), increased creatinine 38%, edema (35%), rash (30%), constipation 30%) and arrhythmias (19%). Events of clinical significance, autoimmune mediated, included interstitial pneumonitis (13%), hypothyroidism (10%), transaminitis(6%), adrenal insufficiency (4%) and vitiligo (2%). Nine pts had pomalidomide dose reductions due to rash, neutropenia, palpitations and fatigue; one pt reduced pembrolizumab for pneumonitis. At a median follow up of 10 months (range: 2-18): 25 pts continue on the study and 23 pts discontinued therapy due to disease progression (n= 15), side effects (n=7) and protocol violation (n=1). Five pts died while on study due to progressive disease (n=3), sepsis (n=1, sAE), and one from a cardiac event. Three additional pts died off therapy. On intent to treat analysis; the overall response rate (ORR) with ≥ Partial response were observed in of 27 of 48 pts (56%) including: sCR (n=4, 8%), nCR (n=3, 6%), VGPR (n=6, 13%), PR (n=14, 29%). Additionally, 7 pts (15%) had minimal response, 9 (19%) had stable disease, 2 progressed and 3 were not evaluable for response. Of 38 double refractory pts ORR was 55% including, sCR (n=2, 5%), nCR (n=2, 5%), VGPR (n=4, 10%) and PR (n=13, 27%). Of 18 high-risk pts ORR was 33% including VGPR (n=2, 11%) and PR (n=4, 22%). Median duration of response for responding pts was 8.8 months and for pts ≥ VGPR, DOR was 10.7 months. Correlation of PD-1 and PD-L1 expression and response will be presented. CONCLUSION: Pembrolizumab, pomalidomide and dexamethasone shows promising durable therapeutic activity and an acceptable safety profile in RRMM pts. ClinicalTrials.gov number, NCT02289222 Disclosures No relevant conflicts of interest to declare.

Lenalidomide has been linked to myelodysplastic syndrome (MDS) after autotransplants for myeloma. Total therapy trials (TT; TT2−/+ thalidomide) and TT3 (TT3a with bortezomib, thalidomide; TT3b with additional lenalidomide) offered the opportunity to examine the contribution of these immune-modulatory agents to MDS-associated cytogenetic abnormalities (MDS-CA) and clinical MDS or acute leukemia (“clinical MDS/AL”). Of 1080 patients with serial cytogenetic studies, MDS-CA occurred in 11% and clinical MDS/AL in 3%. Risk features of MDS-CA included TT3b, age ≥65 years, male gender, levels of β-2-microglobulin >5.5 mg/L, and multiple myeloma relapse. Clinical MDS/AL occurred less frequently in the control arm of TT2 and more often with TT3a and TT3b. Since MDS-CA often antedated clinical disease, periodic cytogenetic monitoring is recommended. Larger CD34 quantities should be collected upfront as the risk of MDS could be reduced by applying higher CD34 doses with transplant. Thus, treatment, host, and myeloma features could be linked to MDS development after therapy for this malignancy. This trial was registered at www.clinicaltrials.gov: TT3A: NCT00081939, TT3B: NCT00572169.

The therapy for multiple myeloma has made major strides over the last 15 years, by and large due to the advances in molecular biology and the focus on patient-oriented translational investigations. Although the survival outcomes have improved significantly, clinical features such as older age, renal insufficiency at diagnosis, primary plasma cell leukemia and extramedullary disease remain major therapeutic challenge. The explosion of data from all the clinical, genomic and proteomic investigations has also made it difficult to assimilate all the information and translate it effectively for clinical practice. Although multiple myeloma is still considered by most though leaders as an incurable but treatable disease, the development of novel diagnostic and therapeutic modalities are bringing optimism of potential curability dream of being curable. Over the last decade, new biologic markers and novel imaging modalities have been explored in the context of clinical trials. The present chapter will attempt to summarize these data and propose how to incorporate this knowledge in current clinical practice.