Loss of TOSO Promotes Richter's Transformation of TCL1A Driven CLL

Abstract Background: The immunoglobulin-like protein TOSO, which has been found to serve as Fc receptor for IgM (FcµR), was shown by us and others to be overexpressed on CLL cells and only weakly expressed on more aggressive B-NHL. However the functional role of TOSO on lymphomagenesis has not been explored so far. Methods: To determine the role of TOSO on lymphoma development, we took advantage of the Eµ-TCL1 transgenic mice, which usually end up with an aggressive (IgVH unmutated) CLL-like phenotype. We generated a novel B cell-specific conditional knockout (KO) mouse model in which EµTCL1 mice (TC or control in the following) were crossbred with TOSO-floxed mice, expressing Cre recombinase under the control of the CD19 promoter (EµTCL1;Tosofl/fl;Cd19cre/wtor TCT in the following). TCT mice were further compared with p53 conditional knockout (EµTCL1;Tp53fl/fl;Cd19cre/wt or TCP). Results: In this study, we compared kinetics, overall survival and phenotype of lymphoma/CLL in TC, TCT and TCP mice. Interestingly, TCTmice developed a very aggressive phenotype and resulted in significantly shorter overall survival compared to TC mice (TCT 274 days vs. TC 346 days; p<0.0001). As expected, mice lacking p53 (TCP) died even more rapidly than TCT mice (median survival: TCP 233 days). Initially, all three genotypes (TC, TCT, TCP) developed a CLL phenotype, exhibiting a CD19 and CD5 positive malignant clone. In the TCT mice, shorter overall survival is accompanied by a stronger increase of blood leukocytes. Flow cytometry analysis confirmed a strong increase of leukemic CD19/CD5-positive B cells in the blood of TCT mice. With only 20 weeks of age, leukemic cells already made up 37.5 % (SD ± 15.47; n=14) of lymphocytes (TC: 14.3 % SD ± 9.81; n=31). At the age of 36 weeks, TCT mice showed even a 3.6-fold elevated malignant cell count compared to control mice (n=35 TC, n=14 TCT; p=0.006). All TCT mice developed a splenomegaly, with spleen weight (p=0.01) and size (p=0.018) significantly increased in 36 week old TCT mice (n=7) compared to TC mice (n=7) and comparable to those from TCP mice. Interestingly, between week 28 and 36, we could observe that most of the TCT mice start losing CD19+ cells in the blood in contrast to TC and TCP mice. Immunohistochemistry revealed the expansion of malignant cells with pleomorphic nuclei and abundant cytoplasm in the spleen and bone marrow, as we know it from Richter`s transformation. To understand the rapid development of leukemia in TCT mice, we first determined the role of the BCR in this model. Interestingly, flow cytometry revealed a higher surface IgM expression (MFI: TCT 9,27; TC 2,05). In addition, in vitro assays revealed a significantly higher resistance of TCT cells towards PI3K inhibition (Idelalisib and Duvelisib) compared to TC cells. To further rule out the role of TOSO under "germinal-center conditions", we stimulated primary human CLL cells with CD40L expressing feeder cells and IL-4. Interestingly, both stimuli (either alone or in combination) resulted in almost complete loss of TOSO on CLL cells. Moreover, we uncovered, that the TOSO promoter is counteractively regulated by NF-κB and BCL6. Furthermore, our data illustrate that DNA hypomethylation of the TOSO promoter is a discriminating characteristic in CLL patients compared to healthy donors, thus explaining the significantly enhanced expression levels. Thus, both, epigenetic regulation and altered NF-κB/ BCL6 expression are critical pathogenetic steps in the development of CLL and aggressive B-NHL by regulating TOSO expression. Conclusion: The transformation of CLL into more aggressive malignancies is still not fully understood. Our data reveal that the loss of TOSO might play a major role in Richter's transformation by upregulation of the BCR and by mimicking the germinal-center phenotype. Disclosures Fingerle-Rowson: Roche: Employment. Wendtner:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann-La Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Morphosys: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hallek:GSK: Research Funding; Mundipharma: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Gilead: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria.

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Deregulation of TNFRSF18 (GITR) Through Promoter CpG Island Methylation Induces Tumor Proliferation in Multiple Myeloma

Blood ◽

10.1182/blood.v118.21.2424.2424 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2424-2424

Author(s):

Yang Liu ◽

Yong Zhang ◽

Phong Quang ◽

Hai T Ngo ◽

Feda Azab ◽

...

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Flow Cytometry ◽

Board Of Directors ◽

Research Funding ◽

Plasma Cells ◽

Cpg Island ◽

Advisory Committees ◽

Brdu Assay

Abstract Abstract 2424 Introduction Tumor necrosis factor receptor super families (TNFRSFs) play an important role in activation of lymphocyte and cell apoptosis. However the function of TNFRSFs in multiple myeloma (MM) remains unknown. Loss of function mutation of Fas antigen (TNFRSF6) was identified in MM cells, thus suggesting the possible role of TNFRSFs in regulating MM pathogenesis. We therefore investigated the epigenetic mechanisms that may mediate inactivation of TNFRSFs and its functional role in MM. Methods Dchip software was utilized for analyzing gene expression dataset. DNA was extracted from both primary CD138+ MM plasma cells and MM cell lines using blood & tissue DNA isolation kit (Qiagen, Inc.). Expression of GITR in primary CD138+ plasma cells was detected by Imunohistochemistry (IHC) DNA methylation was analyzed by methylated DNA immunoprecipitation (Medip) assay and bisulfate sequencing. 5'azacytidine was used to demethylate genomic DNA. Gene expression was detected by qRT-PCR and confirmed at the protein level by flow cytometry and western-blot. Over-expression of GITR was obtained in MM1.S cells by using GITR recombinant plasmid and electroporation. Apoptosis was determined using Annexin/PI staining and flow cytometry analysis. Activation of apoptotic signaling was studied by western blot. Cell survival and proliferation were analyzed by MTT and BrdU assay, respectively. Recombinant GITR-lentivirus was obtained from the supernatant of culture medium after 72 hours transfection in 293 cells. GFP positive MM cells were sorted and analyzed by flow cytometry. In vivo effect of GITR on MM tumor growth was determined by injection of GITR over-expressing MM cells in null mice. Mice skull, femur and vertebrae were isolated after 4 weeks injection. Anti-human CD138+ mAb microbead was used to detect MM cells extracted from mice tissue by flow cytometry. Results Gene-expression profiling showed down-regulation of TNFRSFs, including TNFRSF11A, TNFRSF11B, TNFRSF8, TNFRSF10C, TNFRSF9, TNFRSF21, TNFRSF1B, TNFRSF1A and TNFRSF18, compared to normal plasma cells. Moreover, Our IHC results also showed that GITR expression was positive in primary CD138+ plasma cells from 9 normal bone marrow, but negative in 9 MM samples. Importantly, we found that low GITR expression significantly correlated with MM progression. Indeed, GITR gene levels were lower in smoldering and active MM patients compared to MGUS patients and normal donors. Promoter CpG island (CGI) methylation of GITR was indentified in 5 out of 7 MM primary bone marrow (BM)-derived CD138+ cells but not in normal BM-derived plasma cells. Bisulfate sequencing and Medip assay showed that methylation of GITR was significantly associated with GITR expression in 5 MM cell lines, including MM1.S, OPM1, U266, RPMI and INA6. Promoter CGI of GITR was highly methylated leading to complete silencing of GITR in MM1.S cell line. GITR expression was significantly up-regulated in MM cells upon treatment with the 5'azacytidine. MTT and BrdU assay revealed that the proliferation and survival of MM1.S cells was disrupted in the GITR over-expressing MM1.S cells, notably with inhibition of cell proliferation compared to control vector infected cells. Moreover induction of cytotoxicity in GITR over-expressing cells was confirmed by using GFP competition assay. GITR-induced apoptosis was supported by induction of caspase 8 and 3 cleavage. The inhibition of human CD138+ plasma cell growth in the bone marrow of SCID mice using a disseminated MM xenograft model was observed in the experimental group injected with GITR expressing cells compared to the control group after 4 weeks injection. Conclusion Our findings uncovered a novel epigenetic mechanism contributing to MM pathogenesis, showing the role of GITR methylation as a key regulator of MM cell survival. Disclosures: Roccaro: Roche:. Ghobrial:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Near-Tetraploidy Is Strongly Associated with Development of Richter's Transformation in Chronic Lymphocytic Leukemia Patients Receiving Ibrutinib

Blood ◽

10.1182/blood.v128.22.3198.3198 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3198-3198

Author(s):

Cecelia R. Miller ◽

Amy S. Ruppert ◽

Nyla A. Heerema ◽

Kami J. Maddocks ◽

Jadwiga Labanowska ◽

...

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Board Of Directors ◽

Research Funding ◽

Lymphocytic Leukemia ◽

Complex Karyotype ◽

Advisory Committees ◽

Data Set ◽

Richter’S Transformation ◽

Richter's Transformation

Abstract Ibrutinib is a promising targeted therapy for chronic lymphocytic leukemia (CLL). However, a small subset of patients progress on ibrutinib either through progressive CLL or Richter's transformation. Patients responding to ibrutinib and then progressing with Richter's transformation do so most commonly within the first 2 years of treatment and have an extremely poor prognosis. Identifying biomarkers associated with this transformation is of utmost importance. Near-tetraploidy (4 copies of most chromosomes within a cell) has been reported in various lymphomas; however, its incidence in CLL has not been described. We investigated the prevalence of near-tetraploidy in CLL patients prior to starting ibrutinib and identified it as a pre-treatment biomarker for Richter's transformation. We examined near-tetraploidy in a large series of CLL patients enrolled across four ibrutinib clinical trials at the Ohio State University, for which extensive correlative studies and follow up data are available (previously described by Maddocks et al., JAMA Oncol, 2015). We identified this abnormality in 9 of 300 patients (3.0%, 95% CI: 1.4-5.6) in blood or bone marrow samples taken prior to starting therapy. Near-tetraploidy was detected by the presence of four signals with four or more fluorescence in situ hybridization (FISH) probes and confirmed in the metaphase karyotype of each patient in at least one cell. Near-tetraploidy was associated with aggressive disease characteristics including: Rai stage 3/4 (p=0.03), deletion 17p (p=0.03), and complex karyotype (p=0.01), as well as trisomy 12 (p=0.05). With a median follow-up time of 40.5 months, in patients positive with near-tetraploidy, one patient (11%) progressed with CLL on ibrutinib, six patients (67%) progressed with Richter's transformation, and two patients (22%) were still on treatment. Cumulative incidence of Richter's transformation was significantly higher in patients with near-tetraploidy (Figure; p<0.0001). Notably, near-tetraploidy was not associated with progression with CLL alone (p=0.53). In a multivariable model, both near-tetraploidy (HR 8.66, 95% CI 3.83-19.59, p<0.0001) and complex karyotype (HR 4.78, 95% CI 1.42-15.94, p=0.01) were independent risk factors for discontinuing ibrutinib due to Richter's transformation. Our results suggest that near-tetraploidy is a distinct biomarker to assess in patients initiating ibrutinib which would predict a high risk for Richter's transformation. As a biomarker it will be important to confirm this association in a second independent data set as well as interrogate the distinct pathophysiology of this genomic subset of CLL. Figure Figure. Disclosures Lozanski: Stemline Therapeutics Inc.: Research Funding; Boehringer Ingelheim: Research Funding; Genentech: Research Funding; Beckman Coulter: Research Funding. Jones:Pharmacyclics, LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Andritsos:Hairy Cell Leukemia Foundation: Research Funding. Awan:Novartis Oncology: Consultancy; Pharmacyclics: Consultancy; Innate Pharma: Research Funding. Blum:Pharmacyclics: Research Funding. Woyach:Acerta: Research Funding; Morphosys: Research Funding; Karyopharm: Research Funding.

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Role of Selectins in the Pathogenesis of Multiple Myeloma.

Blood ◽

10.1182/blood.v114.22.951.951 ◽

2009 ◽

Vol 114 (22) ◽

pp. 951-951 ◽

Cited By ~ 1

Author(s):

Abdel Kareem Azab ◽

Phong Quang ◽

Feda Azab ◽

Costas M Pitsillides ◽

John T Patton ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Flow Cytometry ◽

Endothelial Cells ◽

Cell Adhesion ◽

Board Of Directors ◽

Research Funding ◽

Plasma Cells ◽

Advisory Committees

Abstract Abstract 951 INTRODUCTION: Multiple Myeloma (MM) is characterized by widespread disease at diagnosis with the presence of multiple lytic lesions and disseminated involvement of the bone marrow (BM), implying that the progression of MM involves a continuous re-circulation of the MM cells in the peripheral blood and re-entrance into the BM. Selectins are adhesion molecules expressed by activated endothelium of venules and leukocytes, and are involved in the primary interaction of lymphocytes with the endothelium of blood vessels. The binding of selectins serves as a biologic brake, making leukocyte quickly decelerate by rolling on endothelial cells, as the first step of extravasation. In this study, we have investigated the role of selectins and their ligands in the regulation of homing of MM Cells to the BM and the therapeutic implications of this role. METHODS AND RESULTS: We have used flow cytometry to characterize the expression of E, L and P-selectins and their ligands on MM cell lines, patient samples and on plasma cells from normal subjects. We found that all MM cell lines and patient samples showed high expression of L and P, but little of no E-selectin. While normal plasma cells showed low expression of all selectins and ligands.(give numbers) A pan-selectin inhibitor GMI-1070 (GlycoMimetics Inc., Gaithersburg, MD) inhibited the interaction of recombinant selectins with the selectin-ligands on the MM cells in a dose response manner. We have tested the role of the selectins and their ligands on the adhesion of MM cells to endothelial cells and found that MM cells adhered preferentially to endothelial cells expressing P-selectin compared to control endothelial cells and endothelial cells expressing E-selectin (p<0.05). Moreover, we found that blockade of P-selectin on endothelial cells reduced their interaction with MM cells (p<0.01), while blockade of E and L-selectin did not show any effect. Treating endothelial cells with GMI-1070 mimicked the effect of blocking P-selectin. Moreover, we found that treating endothelial cells with the chemokine stroma cell-derived factor-1-alpha (SDF1) increased their expression of P but not E or L-selectin detected by flow cytometry. Neither the blockade of each of the selectins and their ligands nor the GMI-1070 inhibited the trans-well chemotaxis of MM cells towards SDF1-alpha. However, blockade of P-selectin (p<0.001) on endothelial cells by GMI-1070 inhibited the trans-endothelial chemotaxis of MM cells towards SDF1-alpha. Both adhesion to endothelial cells and activation with recombinant P-selectin induced phosphorylation of cell adhesion related molecules including FAK, SRC, Cadherins, Cofilin, AKT and GSK3. GMI-1070 decreased the activation of cell adhesion molecules induced by both recombinant P-selectin and endothelial cells. Using in vivo flow cytometry we found that both anti P-selectin antibody and GMI-1070 prevented the extravasation of MM cells out of blood vessels into the bone marrow in mice. Moreover, we found that, in a co-culture system, endothelial cells protected MM cells from bortezomib induced apoptosis, an effect which was reversed by using GMI-1070, showing synergistic effect with bortezomib. CONCLUSION: In summary, we showed that P-selectin ligand is highly expressed in MM cells compared to normal plasma cells, and that it plays a major role in homing of MM cells to the BM, an effect which was inhibited by the pan-selectin inhibitor GMI-1070. This provides a basis for testing the effect of selectin inhibition on tumor initiation and tumor response to therapeutic agents such as bortezomib. Moreover, it provides a basis for future clinical trials for prevention of MM metastasis and increasing efficacy of existing therapies by using selectin inhibitors for the treatment of myeloma. Disclosures: Patton: GlycoMimetics, Inc: Employment. Smith:GlycoMimetics, Inc: Employment. Sarkar:GlycoMimetics, Inc: Employment. Anderson:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Magnani:GlycoMimetics, Inc.: Employment. Ghobrial:Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau.

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Ofatumumab and Bendamustine in Previously Treated CLL and SLL

Blood ◽

10.1182/blood.v118.21.4615.4615 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4615-4615

Author(s):

Chaitra S. Ujjani ◽

Edmund A Gehan ◽

Pari Ramzi ◽

Catherine Broome ◽

Bruce D. Cheson

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Brain Mri ◽

Viral Reactivation ◽

Multiple Infections ◽

Advisory Committees ◽

Richter’S Transformation ◽

Richter's Transformation ◽

Previously Treated ◽

Grade 3

Abstract Abstract 4615 Background: Despite response rates of 85–95% with fludarabine and rituximab (R)-based therapies in multicenter trials, patients (pts) with CLL invariably relapse. Ofatumumab (O) and Bendamustine (B) have each shown efficacy in relapsed/refractory CLL with ORRs of 68–78% and 44–58%, respectively. While excellent responses have been seen with BR in CLL (77-91%), the combination of O and B has yet to be investigated. In this phase II study, we are combining O and B in previously treated CLL and SLL in order to investigate the efficacy and tolerability of this regimen. We report our experience with the first 5 pts here. Methods: Pts with relapsed/refractory CLL/SLL with adequate performance status and organ function were eligible as long as they had not received B previously. Pts received O 300 mg IV on D −7, followed by O 1000 mg IV on D1 and B 70 mg/m2 on D1, 2 of each cycle (C). Premedications included acetaminophen 650 mg PO, diphenhydramine 50 mg PO, and hydrocortisone 100 mg IV prior to O and Ondansetron 8 mg IV prior to B. Pts received 6 cycles of OB as long as tolerated or until disease progression. The target enrollment is 40 pts. Results: Of the 5 pts on study, the median age was 62 years, 4 were male, and 3 were Rai Stage III/IV. One pt had sole del 13q, 3 had del 11q, and 1 had del 17p cytogenetics. Pts received a mean of 2 prior therapies (range, 1–4). The first 3 pts developed Grade 2 infusion-related reactions with O during C1. Thus, the protocol was amended to increase acetaminophen to 1000 mg and hydrocortisone to 200 mg for O premedication. Three patients developed > Grade 3 neutropenia which delayed C2 treatment in 2 pts. Two pts experienced > Grade 3 anemia requiring transfusion. In addition, multiple infections arose on study. Pt 1 had a Grade 1 URI requiring hospitalization during C1. Pt 2 had a Grade 2 pneumonia with Grade 3 NTP during C1 and a Grade 2 UTI during C2. Pt 4 developed a Grade 3 pneumonia, Grade 3 hepatosplenic fungal infection, and Grade 3 bacteremia after C1. Pt 5 had a Grade 2 URI during C1 and Grade 2 sinusitis during C3. The protocol was amended so that pegfilgrastim was to be given with each cycle. After C1, Pts 1 and 4 developed a systemic neurotoxicity, characterized by blunted affect, weakness, fatigue, and failure to thrive requiring hospitalization. Complete infectious, metabolic, psychological, and neurologic evaluation was negative for Pt 1. Due to his ongoing weakness, he was removed from study after C2 and discharged to rehab. At 3 months he was only able to walk 3 blocks and his affect remained blunted. Pt 4 was found to have pneumonia on admission. With antibiotics, his functional status improved, but his affect remained mildly altered. Proposed etiologies for this neurotoxicity included infection such as viral reactivation or cytokine release storm. The protocol was amended to exclude pts with history of neurologic deficit and to perform a thorough neurologic evaluation including brain MRI, lumbar puncture, and serum and CSF viral serologies and cytokines levels at onset of concerning symptoms. Pts received a median of 2 cycles of therapy (range, 1–6). All showed evidence of response after C1. Pt 1 achieved a clinical CR with C1 but was removed from study after C2 and had recurrent disease at 5 months. Pt 2 achieved a CR after C3 and remains progression-free 5 months after completing C6. Pts 3 and 4 initially showed a response after C1 but developed Richter’s transformation during C2. Pt 5 had a response after C1 and is currently in C4. The most common reasons for stopping therapy were toxicity and Richter’s transformation. Conclusion: OB has significant efficacy in pts with multiply-relapsed and highly-refractory CLL/SLL. However, toxicity is considerable, particularly in terms of infection. In addition, despite an initial response, Richter’s transformation has been reported in two patients. As this is a small cohort with multiple confounding factors, further evaluation is needed. Disclosures: Broome: Alexion: Honoraria, Speakers Bureau. Cheson:Cephalon: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity’s Board of Directors or advisory committees, Research Funding.

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Prognostic Role of IL-6 in POEMS Syndrome

Blood ◽

10.1182/blood-2021-149792 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2700-2700

Author(s):

Maryam Omar ◽

Rahma M Warsame ◽

Morie A. Gertz ◽

Francis K. Buadi ◽

Ronald Go ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Interleukin 6 ◽

Research Funding ◽

Statistical Significance ◽

Poems Syndrome ◽

Reference Ranges ◽

Time To Progression ◽

Advisory Committees

Abstract INTRODUCTION POEMS syndrome is a paraneoplastic disorder that results in multi-organ disease, and Vascular endothelial growth factor (VEGF) is associated with disease activity. There is evidence that the cytokine Interleukin- 6 (IL-6) stimulates VEGF production in several cancer cell lines. It has also been suggested that patients with POEMS syndrome experience symptoms improvement when IL-6 levels are low. Our study aims to understand the role of IL-6 and whether it is a contributor to disease activity in POEMS syndrome. METHODS We conducted a retrospective study of patients (pts) seen at Mayo Clinic within 1 year of diagnosis for POEMS syndrome with an IL-6 level within 3 months of diagnosis between 01/01/2011-05/31/2021 were included. Our database comprised 358 pts,7 were excluded because did not have official diagnosis of POEMS syndrome. Two hundred and ninety-nine pts did not have IL-6 testing within 90 days of diagnosis and were excluded. Clinical data was abstracted from our electronic medical record. Descriptive statistics were used for IL-6 levels. The majority of IL-6 laboratory testing for pts utilized the same reference range. A minority of pts had alternate reference ranges; thus, all IL-6 values and reference ranges were fold-corrected to have a unified reference to determine elevation in IL-6. High IL-6 was considered any value above the normal range, also analyzed pts in quartiles and deciles. Hematologic, VEGF and PET response criteria were utilized to group pts into responders or non-responders. Time to progression (TTP) and overall survival (OS) was calculated using the Kaplan Meier method. Differences between curves were by log rank. Statistical analysis was conducted via JMP software package (SAS, Cary, NC, USA). Univariate analysis was done to determine the prognostic value of IL-6. Statistical significance is considered with p-values <0.05. RESULTS 52 patients from among 352 met criteria and were included for analysis. Twenty-one patients (40%) had elevated IL-6 levels (IQR 5.67, 22.6) at the time of diagnosis. The fold elevation about normal was typically not very high, with a median of 3.1-fold elevation (IQR 1.3, 4.4; and range 1.0, 8.3). The percentage of males in the high IL-6 versus the normal Il-6 group were 90% versus 65%, p=0.03. Compared to normal IL-6, those with elevated IL-6 values had more instances of hepatomegaly (43% vs 16%, p=0.03), ascites (28% vs 6%, p=0 .04), abnormal DLCO (26% vs 3%, p=0.03), mixed bone lesions (57% vs 29%, p= 0.04), and lower serum albumin (range 2.3-3.5 vs 2.5-4.5 g/dL, p=0.0008).There was a trend for lower VEGF values among the high IL-6 group, but this did not meet statistical significance (median 250 vs 438 pg/mL). There was no significant difference in the time to progression between pts with high versus normal IL-6 levels (HR 1.36; p=0.456). Overall survival was significantly longer in pts with normal IL-6 compared to pts with high IL-6 levels (Median OS 67.4 vs 47.8 months, p=0.02). Forty-two pts were evaluated for VEGF response after treatment; there was a significant improvement in time to progression (85.5 vs 14.9 months, p=0.03) in pts who were VEGF responders. Among pts evaluable for a hematologic response (n=15), time to progression in pts with baseline high IL6 was longer in hematologic responders compared to non-responders (p=0.02). Conclusion Although OS was longer for pts with normal IL-6, elevated IL-6 at the time of diagnosis does not prevent pts from achieving disease remission. The study demonstrates that response to treatment rather than interleukin-6 levels in pts with POEMS syndrome is more prognostic. This study is an important initial step into understanding the utility of IL-6 in POEMS syndrome. Figure 1 Figure 1. Disclosures Gertz: Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; Aurora Biopharma: Other: Stock option; Ionis Pharmaceuticals: Other: Advisory Board; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria. Kumar: Oncopeptides: Consultancy; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Merck: Research Funding; Antengene: Consultancy, Honoraria; Tenebio: Research Funding; Novartis: Research Funding; Roche-Genentech: Consultancy, Research Funding; Carsgen: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Dingli: GSK: Consultancy; Novartis: Research Funding; Janssen: Consultancy; Sanofi: Consultancy; Apellis: Consultancy; Alexion: Consultancy. Lin: Janssen: Consultancy, Research Funding; Merck: Research Funding; Novartis: Consultancy; Legend: Consultancy; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Vineti: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; Sorrento: Consultancy; Gamida Cell: Consultancy; Takeda: Research Funding. Kapoor: Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Dispenzieri: Pfizer: Research Funding; Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Alnylam: Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding.

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Different Treatment Approaches to Blast Phase-Myeloproliferative Neoplasms

Blood ◽

10.1182/blood-2021-146945 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3641-3641

Author(s):

Franco Castillo Tokumori ◽

Najla Al Ali ◽

Onyee Chan ◽

David A. Sallman ◽

Seongseok Yun ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Initial Treatment ◽

Research Funding ◽

Clinical Characteristics ◽

Myeloproliferative Neoplasms ◽

Intensive Chemotherapy ◽

Blast Phase ◽

Advisory Committees

Abstract CONTEXT: Transformation to acute myeloid leukemia (AML) occurs in 5-20% of patients with myeloproliferative neoplasms (MPN). Overall survival in blast phase MPN (MPN-BP) is poor, usually in the range of 3 to 6 months, and is not significantly impacted by intensive chemotherapy. Current guidelines favor treatment with a hypomethylating agent (HMA), but survival remains poor, and allogeneic hematopoietic stem cell transplantation (AHSCT) holds the only potential for long term survival. OBJECTIVE: To describe the clinical characteristics and overall survival of MPN-BP according to different treatment approaches. DESIGN: Single-institution, retrospective analysis of 70 MPN patients that progressed to blast phase, who presented to our institution between 2001 and 2020. Transformation to AML defined as >20% myeloblasts in peripheral blood or bone marrow. We stratified the patients according to initial treatment strategy for AML. Baseline variables were compared between groups. Median overall survival (mOS) was measured from time of AML diagnosis to date of death. Kaplan-Meier plots were created to compare mOS. RESULTS: Among 70 MF patients that progressed to AML, initial treatment was: 19 best supportive care (BSC), 25 HMA (20 HMA only and 5 HMA + venetoclax), and 26 intensive chemotherapy (IC) [12 patients received standard "7+3" regimen with daunorubicin/idarubicin and cytarabine, 12 received high-dose cytarabine, cladribine +/- mitoxantrone (CLAG/CLAG-M), and 2 received CPX-351 (Vyxeos)]. Patients receiving IC were younger at time of leukemic transformation than those receiving BSC (median 63.9 years vs 72.9 years; p=0.029) or HMA (median 63.9 years vs. 69.0 years; p=0.026). Additionally, 70% of IC patients had an ECOG performance status of 0 or 1 compared to just 48% of patients receiving either BSC or HMA (p=0.088). Median OS for the entire cohort (n = 70) was 4.8 months. Compared to patients who received active treatment with HMA or IC, those treated with BSC had shorter survival (0.9 months vs 6.4 months; p=0.001). Median survival between patients treated with HMA and IC was not significantly different (4.5 months vs 9.6 months; p=0.13). Patients treated with IC were more likely to proceed to AHSCT (46% vs 5%; p < 0.001). Between HMA and IC groups, there was no difference in time from MPN-BP diagnosis to treatment (median 0.4 months vs 0.3 months; p=0.644) or total number of lines of treatment for MPN-BP. Focusing specifically on the role of AHSCT in patients treated with IC, we found that patients who received AHSCT had significantly longer mOS than those patients who did not (18.9 months vs 4.9 months; p=0.002), suggesting the beneficial role of intensive chemotherapy is critically tied to the ability to subsequently undergo AHSCT. Among patients who underwent AHSCT, 1-year and 2-year OS was 51% and 34%, respectively. In contrast, patients not receiving AHSCT had 1-year and 2-year OS of 14% and 2%, respectively. Independent of age, AHSCT (p=0.008) and receipt of therapy (p=0.017) significantly correlated with longer survival after AML diagnosis. Besides these factors, there were no significant differences in the clinical characteristics between the three groups. Acknowledging the limitations associated with small numbers, we did not note any difference in survival between patients who received HMA vs HMA + venetoclax (p=0.27). CONCLUSIONS: In MPN-BP, patients receiving treatment had superior outcomes to those that received BSC. Initial treatment with intensive chemotherapy was associated with non-significant improvement in survival; however, this appears to be critically linked to the receipt of AHSCT. In appropriate patients, intensive chemotherapy may be reasonable in an effort to provide an effective bridge to AHSCT. Still, this study reinforces the poor prognosis associated with MPN-BP and the desperate need for novel therapeutic approaches in this group of patients. Figure 1 Figure 1. Disclosures Sallman: AbbVie: Membership on an entity's Board of Directors or advisory committees; Magenta: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Kite: Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Aprea: Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Membership on an entity's Board of Directors or advisory committees; Intellia: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau. Sweet: Bristol Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AROG: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Padron: BMS: Research Funding; Kura: Research Funding; Incyte: Research Funding; Blueprint: Honoraria; Taiho: Honoraria; Stemline: Honoraria. Lancet: Daiichi Sankyo: Consultancy; Celgene/BMS: Consultancy; Millenium Pharma/Takeda: Consultancy; BerGenBio: Consultancy; AbbVie: Consultancy; Astellas: Consultancy; Agios: Consultancy; ElevateBio Management: Consultancy; Jazz: Consultancy. Komrokji: PharmaEssentia: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy; Acceleron: Consultancy; Jazz: Consultancy, Speakers Bureau; BMSCelgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Taiho Oncology: Membership on an entity's Board of Directors or advisory committees; Geron: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Kuykendall: Novartis: Honoraria, Speakers Bureau; Prelude: Research Funding; Incyte: Consultancy; PharmaEssentia: Honoraria; CTI Biopharma: Honoraria; Celgene/BMS: Honoraria, Speakers Bureau; BluePrint Medicines: Honoraria, Speakers Bureau; Abbvie: Honoraria; Protagonist: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Outcome with Lenalidomide Plus Dexamethasone Followed by Early Autologous Stem Cell Transplantation In the ECOG E4A03 Randomized Clinical Trial

Blood ◽

10.1182/blood.v116.21.38.38 ◽

2010 ◽

Vol 116 (21) ◽

pp. 38-38 ◽

Cited By ~ 11

Author(s):

David Samuel diCapua Siegel ◽

Susanna Jacobus ◽

S. Vincent Rajkumar ◽

Rafat Abonour ◽

Natalie Scott Callander ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Age Groups ◽

Early Mortality ◽

First Year ◽

Age Group ◽

Newly Diagnosed ◽

Advisory Committees

Abstract Abstract 38 INTRODUCTION: Lenalidomide and bortezomib have moved into the management of newly diagnosed multiple myeloma leading to dramatically improved outcomes. As a consequence, the role of upfront autologous peripheral blood stem cell transplant (ASCT) has become more controversial. The ECOG E4A03 clinical trial randomized newly diagnosed MM patients to lenalidomide with high-dose dexamethasone (LD) vs lenalidomide with low-dose dexamethasone (Ld) (Rajkumar et al Lancet Oncol 2010; 11: 29–37). Upon completing four cycles of therapy, pts had the option of ASCT or continuing on the assigned therapy. The purpose of this abstract is to determine the outcome of patients on this trial pursuing early ASCT according to various age-groups. MATERIALS and METHODS: This is a post hoc, retrospective analysis of overall survival within age subgroups stratified by early ASCT status. This is a landmark analysis including only pts surviving the first 4 cycles of therapy. RESULTS: In all three age-groups studied, 1, 2, and 3-year survival probability estimates with ASCT were excellent (Tables 1, 2, and 3). For patients under the age of 65 who survived the first 4 cycles of therapy, overall survival at 3-years was 94% with early ASCT, 78% in pts continuing protocol therapy. Although direct comparison with patients not going to early transplant is not possible because the assignment to early ASCT versus no early ASCT was not randomized, survival with ASCT at 3-years appeared higher. While we attempt to correct for age, the differences may be influenced by other factors such as performance status, comorbidities, response to therapy, etc. The presumption that treatment related mortality (TRM) should be more problematic for older pts undergoing ASCT is addressed by looking at the >65 and >70yo cohorts. In the >65 age group, one-year mortality is similar between the early ASCT population and the no early ASCT population. In the >70 age group, no adverse impact of early ASCT was seen in the first year on overall survival but the sample size is extremely small. In all age groups early ASCT seemed to mitigate some of the survival disadvantage associated with randomization to the LD arm. CONCLUSIONS: This analysis shows that the strategy of lenalidomide plus dexamethasone induction followed by early ASCT has a remarkably good outcome in terms of overall survival in all age groups studied and supports the continued role of early consolidative ASCT in newly diagnosed patients. The risk of early mortality was notably low in the first year in all age groups. The risk of early mortality seems to increase at 2 years for the LD pts not choosing early ASCT and at 3 years for the Ld pts not choosing early ASCT. Selection bias makes it difficult to compare results for pts that chose early ASCT directly to the patients who did not receive early ASCT in this trial. As such, these results emphasize the need for randomized trials investigating the timing of ASCT in myeloma in the era of novel therapy. Disclosures: Siegel: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Lenalidomide for front line therapy. Abonour:Celgene: Speakers Bureau; Millennium Pharmaceuticals: Speakers Bureau. Callander:Millennium Pharmaceuticals: Research Funding. Fonseca:Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding; Genzyme: Consultancy; Onyx: Research Funding; Otsuka: Consultancy; Medtronic: Consultancy. Vesole:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

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Increased Interleukin-8 (IL8)-CXCR2 Signaling Promotes Progression of Bone Marrow Fibrosis in Myeloproliferative Neoplasms

Blood ◽

10.1182/blood-2020-138843 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 6-7

Author(s):

Andrew Dunbar ◽

Min Lu ◽

Mirko Farina ◽

Young Park ◽

Julie Yang ◽

...

Keyword(s):

Bone Marrow ◽

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Myeloproliferative Neoplasms ◽

Private Company ◽

Advisory Committees ◽

Cd34 Cells

Introduction: Elevated pro-inflammatory cytokines are a hallmark feature of myeloproliferative neoplasms (MPNs). The pro-inflammatory cytokine interleukin-8 (IL8) is increased in patients with myelofibrosis (MF) and correlates with adverse outcome, including overall survival. Previously, the Levine/Fang labs identified increased IL8 secretion from individual CD34+ stem cells in a subset of MF patients. The role of IL8 and its cognate receptors CXCR1/2 in MF pathogenesis has not been delineated. Methods: Single-cell cytokine assays were performed on isolated CD34+ cells from 60 clinically annotated MPN patients (20 MF, 20 PV, 20 ET) using a previously described micro-chip platform (Kleppe et al, Can Disc 2013). 10 healthy donors (CD34+ cells from hip replacements) were used as controls. Integrated RNA-Seq and Assay for Transposase-Accessible Chromatin followed by next-generation sequencing (ATAC-Seq) was performed on CD34+ cells from MPN patients with and without expanded IL8 secreting clones for gene expression/chromatin accessibility analysis. To model the role of IL8-CXCR2 on fibrosis in vivo, the human MPLW515L transplant model (hMPLW515L) of MF was used. Specifically, wild-type (WT) murine bone marrow (Creneg-Cxcr2f/f; Cxcr2WT) or marrow lacking the CXCR2 receptor (VavCre-Cxcr2f/f; Cxcr2KO)were retrovirally infected with MSCV-hMPLW515L-IRES-GFP and transplanted into lethally irradiated WT recipient mice and monitored for disease. Blood counts, chimerism, and flow cytometry were assayed. Moribund mice were sacrificed and assayed for grade reticulin fibrosis and overall survival. Results: Single-cell cytokine assays confirmed an increased proportion of IL8-secreting CD34+ cells in MF patients (40%) in comparison to other MPN sub-types (10% PV/0% ET) (Figure 1A). MF patients with expanded IL8 secreting clones (defined as >50% of total CD34+ cells) had increased leukocytosis (p<0.0001), larger spleen sizes (p=0.0004), greater prevalence of constitutional symptoms (p=0.0084), and higher-grade reticulin fibrosis in marrow (Figure 1B) in comparison to MF patients without prevalent IL8 clones. IHC confirmed increased IL8 expression in marrow biopsies from 8/15 MF patients in comparison to 0/4 normal controls (Figure 1C), and high IL8 expression was also observed in MF splenic megakaryocytes (MKs) as well as in splenic stromal/endothelial cells not seen in normal spleen (Figure 1D). Integrated RNA-Seq/ATAC-Seq analysis of IL8-high MF patients confirmed up-regulation of IL8-CXCR2 signaling and enrichment in pro-inflammatory pathways (i.e TNFa, NFkB, etc) by GSEA, as well as increased expression/accessibility of pro-inflammatory genes S100A8 and S100A9-previously implicated in fibrosis development. Flow analysis of IL8-high MF CD34+ cells revealed enhanced surface expression of CXCR2 and its analog CXCR1, such that MF was characterized by increased IL8 ligand and receptor expression (Figure 1E) and coincided with enhanced NFkB pathway activity (Figure 1F). Consistent with this, colony forming assays of cultured MF CD34+ cells revealed enhanced colony output when cultured with IL8 compared to WT CD34+ cells-an effect ameliorated by co-treatment with the CXCR1/2 antagonist Reparixin (Figure 1G). In vivo, hMPLW515L adoptive transplant with Cxcr2KO hematopoietic donor cells demonstrated improved leukocytosis, thrombocytosis (Figure 2A) and splenomegaly in comparison to Cxcr2WT hMPLW515L recipient mice. Pathologic analysis revealed a reduction in reticulin fibrosis in bone marrow (Figure 2B) and spleen, translating into an improvement in overall survival (Figure 2C). Notably, a significant reduction in dysplastic MKs-a hallmark feature of MF-was also observed in Cxcr2KO hMPLW515L mice (Figure 2D) supporting a role for CXCR2 signaling in MK proliferation. Conclusion: IL8 secreting clones are associated with increased symptom severity and fibrosis grade in MF. Gene expression of MF CD34+ IL8 secreting clones shows up-regulation of inflammatory genes S100A8/A9, implicated in myofibroblast proliferation. Cxcr2 KO abrogates fibrosis formation and prolongs survival in the hMPLW515L model, and CXCR1/2 inhibition impairs colony forming capacity of MF CD34+ cells. These data suggest pharmacologic inhibition of this pathway should be investigated as potential therapy in MF and in PV/ET patients at high risk of fibrotic transformation. Disclosures Fan: IsoPlexis: Current Employment, Current equity holder in private company; Singleron Biotechnologies: Current Employment, Current equity holder in private company. Levine:Morphosys: Consultancy; Prelude Therapeutics: Research Funding; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Amgen: Honoraria; Astellas: Consultancy; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Lilly: Consultancy, Honoraria; Janssen: Consultancy. Hoffman:Protagonist: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Dompe: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Forbius: Consultancy.

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CD79b Expression in Richter's Transformation

Blood ◽

10.1182/blood-2019-128305 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4279-4279 ◽

Cited By ~ 1

Author(s):

John N. Allan ◽

Erica B Bhavsar ◽

Tiziana Vaisitti ◽

Vincent Sarno ◽

Yifang Liu ◽

...

Keyword(s):

Flow Cytometry ◽

B Cell ◽

Board Of Directors ◽

Splice Variant ◽

Research Funding ◽

Surface Expression ◽

Rna Seq ◽

Advisory Committees ◽

Richter's Transformation ◽

Pdx Models

Background The B cell receptor (BCR) is a signaling complex composed of surface immunoglobulin and heterodimer subunits, Igα (CD79a) and Igβ (CD79b) (Sanchez, et al. 1993). Chronic lymphocytic leukemia (CLL) demonstrates dim surface staining of CD79b compared to normal B cells or other B cell malignancies, in part due to overexpression of a splice variant that lacks coding for the extracellular domain (Alfarano, et al. 1999; Cabezudo, et al. 1999). Aggressive lymphomas, like diffuse large B cell lymphomas of non-germinal center origin (DLBCL-ABC), overexpress surface CD79b and can harbor gain of function mutations (Schmitz, et al. 2018). Richter's transformation (RT), a complication of CLL is defined by transformation to a DLBCL-ABC subtype most commonly. Upon transformation outcomes are poor and survival is short with standard therapeutic approaches. Polatuzumab vedotin (Pv), an antibody drug conjugate, targets CD79b on the surface and has obtained FDA approval for relapsed DLBCL in combination with bendamustine and rituximab. Targeting CD79b may represent an attractive therapeutic strategy for patients (pts) with RT. To this end we sought to characterize CD79b expression in RT. Methods Pts with CLL or RT and available paraffin embedded tissue blocks were identified in coordination with Weill Cornell Medicine's (WCM) pathology department. Clone AT107-2 (Bio-Rad, USA) which targets an intracellular epitope was used to stain for CD79b in formalin fixed paraffin embedded (FFPE) tissue sections after optimization following institutional staining procedures. CD79b was classified as either positive (pos) or negative (neg) based on staining pattern and intensity as deemed by a board certified hematopathologist. RT pt derived xenografts (RT-PDXs) were assessed for surface expression of CD79b via flow cytometry. Nonpermabilized cells derived from RT-PDXs were stained using an anti-human CD79b-FITC conjugated antibody (clone CD3-1, Southern Biotech, USA). Mean fluorescence intensity (MFI) was established. RNA seq data was obtained from 2 of 3 RT-PDX models and has been reported previously (Vaisitti, et al. 2018). CD79b transcripts per million (TPM) were analyzed and compared to that of normal lymph node (LN) tissue deposited in the Human Protein Atlas RNA Seq database (HPA-RNA Seq). GraphPad Prism 8.0 was used to perform statistical analysis. Results Nineteen pts with RT and 5 pts with CLL were identified for the study. Median age at diagnosis of the 19 RT pts was 71 years compared to 67 years for the 5 CLL pts. Five RT pts (26%) were treatment naïve (TN) at time of RT. Ten (53%) RT pts transformed on targeted therapy, 6 on BTK inhibitors, 2 on IMiD based therapy, 2 on venetoclax. CD79b stained pos for 16 RT pts (84%) and all 5 (100%) CLL pts. We were not able to identify any correlations between CD79b expression due to low numbers of neg cases. Surface expression of CD79b was evaluated on RT-PDX models from different passages and found to be pos in all 3 models with a median percentage of CD79b+ cells of 45.9% (range 34.6-76%). The median MFI was 2028.5 (range MFI 860-4289). Two of the 3 three models had bimodal populations of cells (pos and neg) whereas the third model was more uniformly pos. RNA seq data from 2 RT-PDX models was available and compared to RNA-seq data from normal LN tissue deposited in the HPA-RNA Seq database. The mean TPM of CD79b for RT-PDX cases was 837.5 compared to 311.5 for normal LN tissue, p=0.028. Conclusion CD79b expression was pos in 84% of FFPE primary RT specimens evaluated. We were able to confirm extracellular CD79b expression with flow cytometry in all 3 RT-PDX models with a median MFI of 2028.5. Surface expression was found to be bimodal in 2 models and uniformly pos in 1 model suggesting tumor heterogeneity. Rna-seq data from RT-PDX models demonstrated higher TPM values in RT-PDX samples compared to normal LN tissue. We conclude that RT expresses CD79b at sufficient levels despite deriving from a CLL cell that historically has demonstrated low surface CD79b expression. Further studies will be undertaken characterizing pos and neg cellular populations focusing on mechanisms of expression and potential differences in splice variant expression. Disclosures Allan: Pharmacyclics LLC, an AbbVie company: Consultancy; Verastem Oncology, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Sunesis Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Consultancy; Janssen: Consultancy, Honoraria; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees. Vaisitti:Verastem Inc: Research Funding; VelosBio Inc.: Research Funding. Joyce:Genentech: Employment. Schulz:Genentech, Inc.: Employment; Roche: Equity Ownership. Deaglio:Verastem Inc: Research Funding; iTeos Therapeutics: Research Funding; VelosBio Inc.: Research Funding. Furman:Genentech: Consultancy.

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Bendamustine and Lenalidomide in Relapsed/Refractory CLL

Blood ◽

10.1182/blood.v118.21.4618.4618 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4618-4618

Author(s):

Chaitra S. Ujjani ◽

Syed M. Karim ◽

Trishna Goswami ◽

Jenny Crawford ◽

Edmund A Gehan ◽

...

Keyword(s):

Phase I ◽

Board Of Directors ◽

Research Funding ◽

Phase I Study ◽

Tumor Lysis Syndrome ◽

Stage I ◽

Advisory Committees ◽

Richter’S Transformation ◽

Richter's Transformation ◽

Grade 3

Abstract Abstract 4618 Background: Front-line regimens for CLL typically include Fludarabine and Rituximab (R), producing ORRs of 90–95% (CR 44–47%) in multicenter trials. Despite these significant responses, patients (pts) invariably relapse and newer regimens are necessary for this relapsed/refractory population. Bendamustine (B) and Lenalidomide (L) have both shown efficacy as single agents in CLL with ORRs of 68–78% and 32–47%, respectively. The combination of these agents, however, has yet to be investigated. In this 2-stage phase I study, we are combining B and L in relapsed/refractory CLL (Stage I) in order to determine the MTD of L for future combination of BLR in CLL (Stage II). We report the preliminary results of the Stage I here. Methods: Pts with relapsed/refractory CLL with adequate performance status and organ function were eligible. This phase I study utilized a standard 3 + 3 dose-escalation design. In Stage I all pts received L 5 mg po daily D-7 through D-1 and allopurinol 300 mg po daily D-2 to D14 of Cycle 1 to minimize the risk of tumor lysis syndrome (TLS). For each 28-day cycle, pts received B 90 mg/m2 IV on D1, 2 with escalating doses of L po daily. Dose levels were 5 mg every other day (Cohort −1), 5 mg daily (Cohort 1), 10 mg daily (Cohort 2), 15 mg daily (Cohort 3), and 20 mg daily (Cohort 4). Pts in Cohorts 2 and higher received L 5 mg po daily during Cycle 1 followed by their respective cohort L doses in subsequent cycles. Pts received 6 cycles of BL followed by 6 cycles of L as long as tolerated or until disease progression. Results: For the 7 pts on study, the median age was 71 years, 100% were male, 43% were Rai Stage III/IV, 43% were CD38+, and 14% had a B-2 microglobulin level > 4. Two pts had sole del 13q, 3 had del 11q, and 1 had del 17p cytogenetics. Pts received a median of 1 prior therapy (range, 1–3). One pt had Richter’s transformation and one pt had PLL. The first pt (Richter’s transformation) in Cohort 1 had a DLT of Grade 3 rash. As rash is a common toxicity with L, the protocol was amended so that only Grade 3 rash that did not resolve to < Grade 2 within 10 days despite steroids or any Grade 4 rash were to be considered DLTs. In addition, L administration was reduced to only 21 days of each 28-day cycle. The trial was reinitiated after these amendments, and 3 new pts were enrolled into Cohort 1. There were no DLTs or Grade 3/4 rash found in this cohort. Three pts were enrolled into Cohort 2, but one suffered fatal septic shock during Cycle 2. No MTD has been reached for L. Common > Grade 3 toxicities included neutropenia (71%) and thrombocytopenia (29%). Pts completed a median of 5 cycles of therapy (range, 2–12). The most common reason for discontinuing therapy was toxicity. The ORR was 57% (CR of 14%). Responses were seen in pts with both sole del 13q and del 11q. The median time to response was 6 mos (range, 3–6 mos). Among the responders, the median length of response was 14 months (range, 13–23+ mo). Cohorts 1 and 2 have been completed. Conclusion: BL demonstrates promising efficacy and tolerability in pts with relapsed/refractory CLL. Further evaluation is needed. Disclosures: Cheson: Celphalon: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celegen: Membership on an entity’s Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Research Funding.

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