Cell Prolymphocytic Leukemia Research Articles

Abstract B76: Evaluation of the novel BET Bromodomain inhibitor BAY 1238097 in lymphoma models identifies EZH2 and MYD88 mutations as potential biomarkers and the bases for combinations

Abstract Introduction. Lymphomas present frequent alterations of proteins involved in the epigenetic regulation of gene expression. BET Bromodomain proteins are epigenetic readers contributing to gene transcription regulation. Here, we present preclinical results on the novel BET Bromodomain inhibitor BAY 1238097, currently in phase I study (NCT02369029), alone and in combination in lymphoma cell lines. Methods. Cell lines derived from diffuse large B-cell lymphoma (DLBCL, 27), mantle cell lymphoma (MCL, 10), splenic marginal zone lymphoma (3), anaplastic large T cell lymphoma (9), pro-lymphocytic leukemia and primary mediastinal large cell lymphoma (1 each) were exposed to increasing concentrations of BAY 1238097 for 72 h followed by MTT assay. Sensitivity was correlated with baseline gene expression profiles and genetic features. Synergy was assessed with the Chou-Talalay combination index (CI): <0.9, synergism; 0.9-1.1 additive effect; >1.2, no benefit. Results. BAY 1238097 had a median IC50 of 208 nM (95%C.I., 157-260). Activity was higher in B- than in T-cell lymphomas (P<0.001), while no differences were observed among B-cell tumor types or DLBCL ABC/GCB subtypes. Anti-tumor activity was mainly cytostatic, as evidenced by LC50 values higher than 1 μM in 43/51 cell lines, with G1-S block (3/3 cell lines treated with BAY 1238097, 500nM/72h). However, LC50 values < 1 μM were obtained in 7/51 (14%) cell lines (all DLBCL/MCL) and apoptosis was confirmed in all of them by Annexin-V/7-AAD staining. Mut EZH2 was associated with higher sensitivity in all cell lines (P<0.05) and in GCB-DLBCL (P<0.05). Also, an EZH2 signature from follicular lymphomas with or without mutEZH2 (Guo et al., CCR 2014) was associated with higher sensitivity in GCB-DLBCL (NES = 1.6, P<0.01). Thus, we evaluated the effect of BAY 1238097 on EZH2 activity. The compound (500 nM, 72 h) down-regulated EZH2 protein levels and H3K27me3 in 4/4 DLBCL (2 wt, 2 mut EZH2). We then analyzed publicly available ChIP-Seq data for HBL1 DLBCL treated with the BET bromodomain inhibitor JQ1 (500 nM, 3 h; Ceribelli et al, PNAS 2014): the treatment reduced BRD4 binding to the EZH2 upstream regulatory region, indicating a direct effect of BET Bromodomain inhibitors on the regulation of the EZH2 mRNA. Finally, we assessed the combination of BAY 1238097 with the EZH2-inhibitor DZNep for 72 h in 8 GCB-DLBCL. The combination was synergistic or additive in 4/5 mut EZH2 GCB-DLBCL (WSU-DLCL2, CI = 0.7; KARPAS422, 0.7; SU-DHL6, 1; SU-DHL4, 1.1), while it did not present any benefit in 3/3 GCB-DLBCL cell lines with wt EZH2 (Toledo, CI = 1.3; DOHH2, CI = 1.6; Farage, CI = 3.1). In ABC-DLBCL L265P-MYD88 (P = 0.05) and high expression of JAK/STAT and IFN signaling genes were positively associated with sensitivity. Since MYD88 is a known target of BET Bromodomain inhibitors (Boi et al, CCR 2015), we assessed the combination of BAY 1238097 with the BTK-inhibitor ibrutinib for 72 h and synergism was observed in 2/2 ABC-DLBCL cell lines harboring L265P-MYD88 (OCI-Ly10, CI = 0.8; TMD8, 0.6). No benefit was observed in 2/2 ABC-DLBCL with wt MYD88 (SU-DHL2, CI = 1.7; U2932, 1.4). Conclusions. BAY 1238097 was active in preclinical models of mature lymphomas. Mutations in EZH2 and MYD88 appeared as potential biomarkers and suggested rational combinations to be further explored. Citation Format: Elena Bernasconi, Eugenio Gaudio, Chiara Tarantelli, Luciano Cascione, Ivo Kwee, Andrea Rinaldi, Afua A. Mensah, Anastasios Stathis, Matthias Ocker, Emanuele Zucca, Bernard Haendler, Francesco Bertoni. Evaluation of the novel BET Bromodomain inhibitor BAY 1238097 in lymphoma models identifies EZH2 and MYD88 mutations as potential biomarkers and the bases for combinations. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B76.

Targeting Interleukin-2-inducible T-cell Kinase (ITK) and Resting Lymphocyte Kinase (RLK) Using a Novel Covalent Inhibitor PRN694

Interleukin-2-inducible T-cell kinase (ITK) and resting lymphocyte kinase (RLK or TXK) are essential mediators of intracellular signaling in both normal and neoplastic T-cells and natural killer (NK) cells. Thus, ITK and RLK inhibitors have therapeutic potential in a number of human autoimmune, inflammatory, and malignant diseases. Here we describe a novel ITK/RLK inhibitor, PRN694, which covalently binds to cysteine residues 442 of ITK and 350 of RLK and blocks kinase activity. Molecular modeling was utilized to design molecules that interact with cysteine while binding to the ATP binding site in the kinase domain. PRN694 exhibits extended target residence time on ITK and RLK and is highly selective for a subset of the TEC kinase family. In vitro cellular assays confirm that PRN694 prevents T-cell receptor- and Fc receptor-induced cellular and molecular activation, inhibits T-cell receptor-induced T-cell proliferation, and blocks proinflammatory cytokine release as well as activation of Th17 cells. Ex vivo assays demonstrate inhibitory activity against T-cell prolymphocytic leukemia cells, and in vivo assays demonstrate durable pharmacodynamic effects on ITK, which reduces an oxazolone-induced delayed type hypersensitivity reaction. These data indicate that PRN694 is a highly selective and potent covalent inhibitor of ITK and RLK, and its extended target residence time enables durable attenuation of effector cells in vitro and in vivo. The results from this study highlight potential applications of this dual inhibitor for the treatment of T-cell- or NK cell-mediated inflammatory, autoimmune, and malignant diseases.

Hematological Malignancies: Analysis of Myelogram Results over 21 Years in Lome Teaching Hospitals

Objectives: Determine the frequency of malignancies diagnosed in myelogram seen in hematology services of Campus and Sylvanus Olympio Teaching Hospitals in Lome from 1992 to 2013. Study the epidemiology profile of these diseases. Materials and methods: It was an analytical retrospective study of 469 cases of malignancies diagnosed in 1511 myelograms during 21 years in both teaching hospital of Lome. Results: Blood disorders represent 31.70% of the results of myelogram performed during 21 years in the Teaching Hospital of Lome. Each year, there is an average of 22.3 cases diagnosed hematological malignancies. The most hematological malignancies were Kahler's disease (28.57%), chronic myeloid leukemia (24.52%), chronic lymphocytic leukemia (22.17%), acute lymphoblastic leukemia (12.58%) and acute myeloid leukemia (8.10%). Other (4.05%) were represented by the essential hypereosinophilic syndrome (4 cases), hairy cell leukemia (4 cases), Sezary lymphoma (3 cases), essential thrombocythemia (3 cases), Waldenstrom's disease (2 cases), acute myelomonocytic leukemia (1 case), prolymphocytic leukemia (1 case) and plasma cell leukemia (1 case). By gender, the CLL is most predominant in women against CML in men. Hemopathies were observed at all ages of life. Conclusion: Hematological malignancies are diagnosed in the Teaching Hospital of Campus and Sylvanus Olympio in Lome with a high relatively frequency. This prevalence must be higher if all cases of malignancies diagnosed in Togo were recorded in a national cancer register. This study aims to knowledge of epidemiological aspects of hematological malignancies and improve the care of patients with hematological malignancies by the provision of adequate anti-mitotic drugs.

Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) and Resting Lymphocyte Kinase (RLK) Using a Novel Covalent Inhibitor PRN694

▪IL2-inducible T-cell kinase (ITK) and resting lymphocyte kinase (RLK) are two members of the Tec family of non-receptor tyrosine kinases which are essential mediators of intracellular signaling in both normal and neoplastic T and natural killer (NK)-cells. ITK-deficient mice display alterations in T cell receptor (TCR) responses including proliferation, cytokine production and activation of downstream pathways, and these defects are exacerbated by RLK deficiency. Given their critical roles, inhibitors of ITK and RLK have therapeutic potential in a number of human autoimmune diseases, inflammatory conditions, and malignancies. Specific inhibitors targeting both ITK and RLK have not been reported and until very recently it has been challenging to develop specific inhibitors with clinical potential given the homology to many other human kinases. Targeting cysteine residues within the ATP binding pocket of kinases is a safe and effective way to design and optimize highly potent and selective kinase inhibitors. In this study, we describe preclinical mechanism of action studies of a novel covalent ITK/RLK inhibitor, PRN694, which covalently binds to cysteine moieties 442 of ITK and 350 of RLK and blocks their kinase activities.We undertook the design of highly selective ITK/RLK inhibitors using a combination of tailored covalency and structure-based design. Molecular modeling and a synthetic feasibility assessment led to the prioritization of several small focused compound libraries. The structure-based medicinal chemistry optimization of one such library culminated in the identification of PRN694. The in vitro selectivity and potency of PRN694 against a panel of 250 kinases revealed only small number of kinase targets, and in a microfluidic kinase assay, PRN694 exhibited high selectivity and potency against ITK and RLK with IC50 values of 0.3 nM and 1.3 nM, respectively. This selectivity was validated in Jurkat T cells with mutated ITK or overexpressed RLK. As expected, PRN694 suppressed a variety of downstream TCR pathways including nuclear activation of NFAT1 and cytoplasmic PLCγ1 and IKBα in TCR-activated Jurkat cells expressing wild type ITK. However, when the covalent binding site for PRN694 was removed, using ITK-C442A, this suppressive effect was lost, indicating specific covalent interaction with ITK. Furthermore, we demonstrated that only PRN694 was able to ablate TCR-induced activation in Jurkat cells which stably express RLK in addition to ITK. These data confirmed that PRN694 was a dual inhibitor of ITK and RLK and could block downstream TCR-activation in T-cells that express both complementary TEC-kinases. In vitro cellular assays also confirmed that PRN694 could prevent TCR or Fc receptor (FcR) - induced cellular and molecular activation in primary T or NK cells, inhibit TCR-induced T-cell proliferation without direct cytotoxicity, and block pro-inflammatory cytokine (including IL-2, TNFα, and IFNγ) release as well as activation of Th17 cells. Additionally, in vivo assays demonstrated durable pharmacodynamic effects of PRN694 on ITK. At 1 hour, 6 hour and 14 hour time points, the percentages of ITK occupancy were 98%, 95% and 54% respectively, and the concentrations of PRN694 in the plasma were 1530 ng/ml, 359.3 ng/ml and 14.8 ng/ml respectively.Further, we examined potential therapeutic applications of PRN694 in the treatment of T-cell leukemias or T-cell driven inflammation. Our results demonstrated an effective blockade of TCR stimulation by PRN694 in the HH cutaneous T-cell lymphoma cell line and primary T-cell prolymphocytic leukemia (T-PLL) cells, suggesting a potential clinical application of this compound in the treatment of T-cell leukemias. ITK and RLK play a critical role in T-cell driven inflammation. Therefore, we also tested the effect of PRN694 on an oxazolone induced delayed type hypersensitivity (DTH)reaction using a well-established in vivo model of inflammation driven by cell-mediated immunity, and found that PRN694 treatment significantly inhibited the DTH reaction.In conclusion, we designed and characterized a novel covalent ITK/RLK inhibitor, PRN694, which has direct therapeutic potential for the treatment of T or NK cell related diseases including inflammation, autoimmune diseases, and malignancy. DisclosuresPorcu:Actelion: Honoraria; Infinity: Research Funding; Seattle genetics: Research Funding; Celgene: Honoraria; United States Cutaneous Lymphoma Consortium: Membership on an entity’s Board of Directors or advisory committees; Cutaneous Lymphoma Foundation: Membership on an entity’s Board of Directors or advisory committees. Bradshaw:Principia Biopharma: Employment, Equity Ownership. Owens:Principia Biopharma, Inc: Employment, Equity Ownership. Brameld:Principia Biopharma: Employment, Equity Ownership. Funk:Principia Biopharma Inc.: Employment, Equity Ownership. Hill:Principia Biopharma: Employment. Johnson:Principia Biopharma: Research Funding. Dubovsky:Principia Inc.: Research Funding.

An Unusual Cause of Delirium and Debility: Refractory Hypercalcemia in a Man with B‐Cell Prolymphocytic Leukemia

An Unusual Cause of Delirium and Debility: Refractory Hypercalcemia in a Man with <scp>B</scp>‐Cell Prolymphocytic Leukemia

Tcrδ translocations that delete the Bcl11b haploinsufficient tumor suppressor gene promote atm-deficient T cell acute lymphoblastic leukemia

ATM is the master regulator of the cellular response to DNA double strand breaks (DSBs). Deficiency of ATM predisposes humans and mice to αβ T lymphoid cancers with clonal translocations between the T cell receptor (TCR) α/δ locus and a 450 kb region of synteny on human chromosome 14 and mouse chromosome 12. While these translocations target and activate the TCL1 oncogene at 14q32 to cause T cell pro-lymphocytic leukemia (T-PLL), the TCRα/δ;14q32 translocations in ATM-deficient T cell acute lymphoblastic leukemia (T-ALL) have not been characterized and their role in cancer pathogenesis remains unknown. The corresponding lesion in Atm-deficient mouse T-ALLs is a chromosome t(12;14) translocation with Tcrδ genes fused to sequences on chromosome 12; although these translocations do not activate Tcl1, they delete the Bcl11b haploinsufficient tumor suppressor gene. To assess whether Tcrδ translocations that inactivate one copy of Bcl11b promote transformation of Atm-deficient cells, we analyzed Atm−/− mice with mono-allelic Bcl11b deletion initiating in thymocytes concomitant with Tcrδ recombination. Inactivation of one Bcl11b copy had no effect on the predisposition of Atm−/− mice to clonal T-ALLs. Yet, none of these T-ALLs had a clonal chromosome t(12;14) translocation that deleted Bcl11b indicating that Tcrδ translocations that inactivate a copy of Bcl11b promote transformation of Atm-deficient thymocytes. Our data demonstrate that antigen receptor locus translocations can cause cancer by deleting a tumor suppressor gene. We discuss the implications of these findings for the etiology and therapy of T-ALLs associated with ATM deficiency and TCRα/δ translocations targeting the 14q32 cytogenetic region.

B-cell prolymphocytic leukemia: a specific subgroup of mantle cell lymphoma

AbstractB-cell prolymphocytic leukemia (B-PLL) is a rare mature B-cell malignancy that may be hard to distinguish from mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL). B-PLL cases with a t(11;14) were redefined as MCL in the World Health Organization 2008 classification. We evaluated 13 B-PLL patients [7 being t(11;14)-positive (B-PLL+) and 6 negative (B-PLL−)] and compared them with MCL and CLL patients. EuroFlow-based immunophenotyping showed significant overlap between B-PLL+ and B-PLL−, as well as between B-PLL and MCL, whereas CLL clustered separately. Immunogenotyping showed specific IGHV gene usage partly resembling MCL. Gene expression profiling showed no separation between B-PLL+ and B-PLL− but identified 3 subgroups. One B-PLL subgroup clustered close to CLL and another subgroup clustered with leukemic MCL; both were associated with prolonged survival. A third subgroup clustered close to nodal MCL and was associated with short survival. Gene expression profiles of both B-PLL+ and B-PLL− showed best resemblance with normal immunoglobulin M-only B-cells. Our data confirm that B-PLL+ is highly comparable to MCL, indicate that B-PLL− also may be considered as a specific subgroup of MCL, and suggest that B-PLL is part of a spectrum, ranging from CLL-like B-PLL, to leukemic MCL-like B-PLL, to nodal MCL-like B-PLL.

Primary refractory T‐cell prolymphocytic leukaemia treated with daily administration of Alemtuzumab plus high‐dose methylprednisolone

European Journal of HaematologyVolume 92, Issue 4 p. 360-361 Letter to the Editor Primary refractory T-cell prolymphocytic leukaemia treated with daily administration of Alemtuzumab plus high-dose methylprednisolone Edward Renaudon-Smith, Edward Renaudon-Smith Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UKSearch for more papers by this authorJohn G. Gribben, John G. Gribben Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, UKSearch for more papers by this authorSamir G. Agrawal, Corresponding Author Samir G. Agrawal Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK Academic Haematology, Pathology Group, Blizard Institute, Queen Mary University of London, London, UK Correspondence Samir G. Agrawal, Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London EC1A 7BE, UK. Tel: +44 203 465 5075; Fax: +44 207 796 3979; e-mail: [email protected]Search for more papers by this author Edward Renaudon-Smith, Edward Renaudon-Smith Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UKSearch for more papers by this authorJohn G. Gribben, John G. Gribben Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, UKSearch for more papers by this authorSamir G. Agrawal, Corresponding Author Samir G. Agrawal Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK Academic Haematology, Pathology Group, Blizard Institute, Queen Mary University of London, London, UK Correspondence Samir G. Agrawal, Division of Haemato-Oncology, St Bartholomew's Hospital, Barts Health NHS Trust, London EC1A 7BE, UK. Tel: +44 203 465 5075; Fax: +44 207 796 3979; e-mail: [email protected]Search for more papers by this author First published: 14 December 2013 https://doi.org/10.1111/ejh.12248Citations: 3Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume92, Issue4April 2014Pages 360-361 RelatedInformation

State of the Art Review: New Insights in T Cell Prolymphocytic Leukemia

T cell ProLymphocytic Leukemia (T-PLL) is a rare lymphoid malignancy and is typified by its aggressive presentation and chemo-resistance. Given its rarity, haemato-oncologists are likely to manage only a handful of cases across their career and therefore making the diagnosis is the initial challenge. This diagnosis is critical, as recent data suggests that choosing specific treatment options, such as alemtuzumab, is important in improving outcomes.

EBMT Prospective Non-Interventional Study On Allogeneic Hematopoietic Stem Cell Transplantation In T-Prolymphocytic Leukemia (T-PLL). Preliminary Analysis Of 43 Patients

T-PLL is very rare disease with aggressive course and poor prognosis. Our earlier retrospective study (Wiktor-Jedrzejczak et al. Leukemia 2012;26:972-6) of 41 patients with T-PLL has shown that allogeneic stem cell transplantation (allo-SCT) may provide effective disease control in some of them. However, this study (similarly to many other retrospective studies) was based on very heterogeneous material and included mainly patients with advanced disease. MethodsSince the extreme rarity of the disease and existing regulations preclude performance of prospective randomized trial in such a situation, we proposed another approach: After a careful review process expert recommendations for the diagnosis and treatment of T-PLL by allo-SCT were prepared and published on the EBMT website in 2007. Subsequently a non-interventional study on the outcome of allogeneic transplantation was initiated and continued to recruit patients until 2012. Inclusion criteria were: T-PLL diagnosed at least by immunophenotype, age between 18 and 65 years, Karnofsky performance status ≥ 60% with adequate renal and liver function, first or second-line therapy before transplantation, life-expectancy at the time of screening of at least 3 months. ResultsThis preliminary analysis covers 43 patients with T-PLL confirmed by immunophenotyping. The median age was 54 years (30 years to 63 years) and the male to female ratio was 31/12. The median time from diagnosis to transplant was 7.8 months. Twenty-six patients were in complete remission (CR), nine in partial remission, seven patients in stable or progressive disease, and one patient in unknown disease status at SCT. In line with the recommendations, 37 patients had received alemtuzumab as part of initial treatment and 6 patients did not. Donors were HLA-identical siblings in 14 patients, a matched other relative in one patient, mismatched relatives in two patients, and matched unrelated donors in 26 patients. The source of stem cells was peripheral blood in 40 patients and cord blood in 3 patients. 25 patients (58 %) received reduced intensity conditioning. In 16 patients conditioning included total body irradiation.With a median follow-up of 49.8 months in surviving patients, 3-year RFS and OS was 38% (95% CI, 25 to 57%) and 48% (95% CI, 35 to 66%), respectively. There was a tendency for better survival for patients transplanted in CR but the difference was not significant. However, non-relapse post-transplant mortality was significantly lower in this first group of patients. Other variables evaluated including use of alemtuzumab prior transplantation, type of the donor or conditioning also did not show significant differences for this number of patients. The three-year non-relapse mortality and relapse incidence were 32% and 30%, respectively. ConclusionThese data confirm that allo-HSCT may provide effective disease control in selected patients with T-PLL. Preliminary results of our prospective study seem to be better than earlier reports of retrospective analyses. In part this could be due to better patient selection and compliance with EBMT recommendations to offer allogeneic SCT early in the course of disease. Disclosures:Off Label Use: alemtuzumab, use in the pretransplantation treatment of T cell prolymphocytic leukemia.

Clinical and laboratory features of T-cell prolymphocytic leukemia in China

To investigate the clinical and laboratory characteristics and survival of Chinese patients with T- cell prolymphocytic leukemia (T-PLL). Eleven patients with T-PLL admitted in our hospital from Jan 2006 to Oct 2012 were retrospectively analyzed. Of the 11 patients, nine were males and two females, with the median age of 56.0(19-69) years old. All the patients, except for three, presented with leukocytosis. The incidence of hyperleukocytosis (1/11) was less frequent than that in the British series (75%) (P=0.000). Lymphocyte counts in peripheral blood were increased in 9 of the 11 patients with the median absolute lymphocyte count (ALC) of 17.22(0.58-148.83)×10⁹/L. Superficial lymphadenopathy and splenomegaly were the most common physical signs. It was common that serum lactate dehydrogenase (LDH) and beta 2 microglobulin(β2-MG)were higher than normal level. All cases were positive for CD2/CD3/CD5/TCRαβ, negative for CD1a /HLA-DR and TdT, and most of them were strong positive for CD7 expression. By chromosome analyses, most cases. (9/10) have normal chromosome. This rate is significantly higher than that of the British and American series (3% and 25%, respectively) (P=0.000, P=0.001). The 14q11 abnormality and trisomy 8q, which are common among Western cases, were not observed in any of our cases. With a median follow-up of 23.0 months, three patients died. Two year progress free survival (PFS) and overall survival (OS) were 53.3% and 50%, respectively. There were 3 patients with PFS over a number of years, whether it should be considered as the T-chronic lymphocytic leukemia (T-CLL) is worthy of further studies. The common clinical manifestations of T-PLL patients were increased lymphocyte counts and lymphadenopathy as well as splenomegaly. And most cases have high level of blood LDH and β2- MG and normal chromosome karyotype.

Indolente Lymphome: Klassifikation, Klinik und Behandlung

The malignant lymphomas comprise a heterogeneous group of neoplastic diseases of the lymphatic system. In the WHO classification 70 different entities are subdivided. Each type of lymphoma is defined as a disease with specific clinical characteristics, as well as morphological, immunophenotypic and genetic characteristics. The indolent lymphomas include follicular lymphoma, marginal zone lymphoma, Lymphoplasmacytic lymphoma, small cell lymphocytic lymhoma/chronic lymphocytic leukemia, prolymphocytic leukemia and hairy cell leukemia. Indolent lymphomas are characterized by slow growth and a chronic course of the disease. Antibody-based therapies, have significantly improved the prognosis, nevertheless there is no curative treatment. Watch and wait is still an reasonable option in asymptomatic patients. The goal of therapy has been to maintain the best quality of life. and to avoid late toxicities. The following review presents the current treatment options.

B-Cell Prolymphocytic Leukemia and Hairy Cell Leukemia: New Advances in Biology and Treatment

SUMMARY B-cell prolymphocytic leukemia and hairy cell leukemia are mature lymphoid neoplasms recognized by WHO classification as distinct entities. The diagnosis relies on a constellation of clinical and laboratory features. B-cell prolymphocytic leukemia is a rare disease that lacks a genetic signature and represents a challenge to clinicians, due to the limited information on its pathogenesis, the difficulty of setting up prospective clinical trials and its refractoriness to treatments used in other chronic lymphoid neoplasms. By contrast, major advances have taken place in the understanding of the pathogenesis of hairy cell leukemia, as well as in the therapeutic armamentarium available for this disease. In this review, data will be presented on the natural history, pathogenesis, diagnosis and current therapies for these two leukemias.

Acute Leukemias Following a Diagnosis of Colorectal Cancer: Are They Therapy-Related?

Abstract 1453▪▪This icon denotes a clinically relevant abstractApproximately 140,000 patients per year are diagnosed with colorectal cancer in the United States. Historically, treatment modalities have included surgery, 5-fluourouracil (5-FU) and/or radiation. Over the past ten years standard treatment has evolved and now includes platinum compounds such as Oxaliplatin, the topoisomerase I inhibitor Irinotecan, and the oral analogue of 5-FU, Capecitabine. Rectal cancer often utilizes these agents in a neoadjuvant fashion with concomitant radiation therapy, followed by surgery and postoperative chemotherapy. The incidence of therapy related acute myeloid leukemia (t-AML) has been well described after treatment for breast cancer and lymphoma and occurs most commonly in patients previously treated with alkylating agents or topoisomerase II-active agents (epipodophylotoxins or anthracyclines). However, the occurrence of acute leukemia after a diagnosis of colorectal cancer has never been systematically investigated in a large clinical database.Using ICD-9 codes for leukemia and colorectal cancer, we identified 37 patients seen at Memorial Sloan-Kettering Cancer Center since 1970 with colon cancer, rectal cancer, or anal cancer who were subsequently diagnosed with leukemia or a myelodysplastic syndrome (MDS). Of these 37 patients, 23 had colon cancer, 13 had rectal cancer and 1 had anal cancer. Treatments for the primary malignancy included: external beam radiation alone (2), chemotherapy alone (10), chemotherapy in combination with radiation (12) and surgery alone (13). The most common leukemia was acute myeloid leukemia (20) followed by MDS (8), Pre-B cell acute lymphoblastic leukemia (ALL) (4), acute promyelocytic leukemia (APL) (3), T-ALL (1) and T- cell prolymphocytic leukemia (PLL) (1). Of the 8 patients with MDS, 4 had chronic myelomonocytic leukemia. Among patients who received chemotherapy or combined chemoradiation the most common chemotherapeutic agents were 5-Fluorouracil (19) followed by Oxaliplatin (8), intrahepatic Floxuridine (2), Irinotecan (1) and Mitomycin (1). The median time from treatment with chemotherapy and/or radiation to diagnosis of acute leukemia or MDS was 41 months (range 10 months – 135 months). The most common cytogenetic abnormalities of the patients with MDS or AML were monosomies and deletions in chromosomes 5, 7, and 12. Of the 4 patients with Pre B-ALL, 3 had t(9;22). Interestingly of the 23 patients with myeloid leukemia, 3 (13%) patients developed the APL subtype with the disease defining t(15;17). Two of these three patients had received neo-adjuvant external beam radiation and 5-FU, one received adjuvant treatment with Oxaliplatinand one was treated with surgery alone. The latency period between diagnosis or treatment of colorectal cancer and the development of APL ranged from 10 to 20 years.Table 1Patient CharacteristicsM/F23/14Type of Lower GI MalignancyColon23Rectal13Anal1TreatmentSurgery Alone13Radiation Alone2Chemo-radiation12Chemotherapy Alone105-Fluorouracil19Oxaliplatin8Intrahepatic Floxuridine2Irinotecan1Mitomycin1Median Latency period (range)41 months (10-135 months)Type of leukemiaAML (non-APL)20APL3MDS4CMMOL4ALL Ph pos3ALL Ph neg1T-ALL1T-PLL1In conclusion, to our knowledge this is among the first uses of a comprehensive clinical database to investigate the occurrence of acute leukemia and MDS after the diagnosis and/or treatment of a colorectal or anal malignancy. Our finding that the most common chromosomal abnormalities seen in patients who developed MDS or AML involve chromosomes 5 and 7, similar to t-AML suggests, that some of these leukemias are therapy related. It may be that the widespread adoption of newer platinum compounds will precipitate t-AML. Future studies of larger databases of patients may help establish if the acute leukemias seen after colorectal cancer are related to prior exposure to anti-cancer therapy. Disclosures:Douer:Teva: Consultancy.

Cerebriform variant type of T cell prolymphocytic leukemia with complex karyotype including an additional segment at 1p36.1

We describe two patients with T cell prolymphocytic leukemia (T-PLL) who exhibited the same complex karyotype, including an additional segment at 1p36.1. One presented with secondary progression following an initial stable clinical course, and the other with typically progressive disease. Features of the cerebriform variant were identified in the peripheral blood of both patients. Aggressive symptoms, such as lymphocytosis, lymphadenopathy, pleural effusion, cutaneous involvement and hepatosplenomegaly, developed during the progressive phases. Levels of serum soluble interleukin 2 receptor increased when symptoms worsened. These patients did not have the karyotypic 14q11 abnormality and trisomy 8q that are features of non-Japanese patients. The prognoses of these patients were poor; one survived for 2 months and the other survived for 10 months after progression. A chromosomal abnormality may occur in other types of aggressive T-PLL, particularly when extramedullary infiltration is a feature.

Purine Nucleoside Analogs in the Treatment of Rarer Chronic Lymphoid Leukemias

Purine nucleoside analogues (PNA) are the cytotoxic agents highly active in the treatment of indolent lymphoid malignancies. These drugs have chemical structure similar to adenosine or deoxyadenosine. PNAs are characterized by a similar mechanism of cytotoxicity both in proliferating and quiescent cells, such as inhibition of DNA synthesis, inhibition of DNA repair and accumulation of DNA strand breaks. In addition, PNAs induce apoptosis which is the end-point of their action. Older PNAs, pentostatin (DCF; 2'- deoxycoformycin), cladribine (2-CdA; 2-chloro-2'-deoxyadenosine) and fludarabine (2-fluoro-9-(-D-arabinosyl)-adenine) were approved by Food and Drug Administration (FDA) for the treatment of hematological malignancies. In addition three novel PNAs: clofarabine (CAFdA), nelarabine (ara-G) and forodesine (immucillin H, BCX-1777) have been synthesized and introduced into preclinical studies and clinical trials. This review summarizes current knowledge on the mechanism of action and pharmacokinetic properties of older and new PNAs. Clinical activity and toxicity of PNAs, especially in hairy cell leukemia (HCL), hairy cell leukemia variant (HCL-V), prolymphocytic leukemia (PLL) and other rarer chronic lymphoid leukemias, are also presented. 2-CdA and DCF, introduced in the 1980s, changed radically the treatment modality, inducing complete and durable responses in the majority of patients with HCL. In contrast, the results of the treatment of HCL-V with PNA are rather poor. There are also several reports indicating activity of PNAs in PLL and large granular lymphocyte leukemia. Clofarabine, nelarabine and forodesine need further investigation in rarer lymphid leukemias, to better define their status in the treatment of these disorders.

Translocation t(8;14)(q24;q32) as a clue for the diagnosis of B cell prolymphocytic leukemia

Case report of a translocation : Translocation t(8;14)(q24;q32) as a clue for the diagnosis of B cell prolymphocytic leukemia.

Epigenetic Modulation of Alemtuzumab Mediated Antileukemia Effects and Resistance in T- Cell Prolymphocytic Leukemia

Abstract 2440T-Cell prolymphocytic leukemia (T-PLL) is an aggressive chemotherapy-resistant hematological malignancy. This disease is more frequently reported in men and is exclusively reported in adults. Raised lymphocyte count, skin lesions and enlarged organs are the frequent clinical symptoms evident in this disease. T-PLL affects mature post-thymic T-cells. Most cases have the CD4+CD8- phenotype; however, 25% of cases do have the CD8+/CD4- phenotype. Currently there is no treatment available that achieves durable complete remission of T-PLL. Current frontline treatment consists of alemtuzumab, an anti CD52 antibody that is expressed on T and B cells and in most PLL patients. This treatment induces complete remissions (CR) in the majority (>50%) of patients that are not durable; median duration of remission is 6 months.The first T-PLL patient exhibited de novo alemtuzumab resistance that we hypothesized was epigenetic in nature. Based on our work and that of others in B cell malignancies, we added cladribine (2-cda; 5mg/m2 d 1–5) while continuing alemtuzumab. The patient had a dramatic decline in her WBC count (Fig. 1) and achieved a peripheral blood complete remission by flow cytometry and PCR. Patient 2 was treated with alemtuzumab alone with complete remission that lasted 6 months when he relapsed with WBC count of 600,000 (Fig. 1). He underwent pheresis and was initiated on treatment with alemtuzumab and cladribine with some response but a pattern consistent with epigenetic resistance. The histone deacetylase inhibitor (HDACi), SAHA (vorinostat), was added (400 mg daily × 5 days) with a rapid decline in WBC count and CR by flow cytometry (Fig. 1). Based on these encouraging results, we have treated 3 additional patients in the frontline setting with alemtuzumab and cladribine (Fig. 1). All have responded with rapid decline in WBC counts with complete remission by flow cytometry and PCR. All of these newly diagnosed patients remain in complete remission by flow cytometry and PCR with followup of 1–14 months.Correlative science experiments have included transcriptional arrays and well as Q-RT PCR for candidate genes identified using the HELP (Hpa II enriched Ligation Mediated PCR)assay in mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) patients treated with cladribine and rituximab with or without SAHA. Microarray gene expression analysis was performed using total RNA from four normal donors and four T-PLL patients. One pre-treatment and one post-treatment sample was obtained and analyzed from each of these four T-PLL patients. The whole blood samples that were acquired from the normal donors were CD3 enriched and tested for purity. Data obtained was normalized and run on the Gene Set Enrichment Analysis (GSEA) program. Biological gene patterns were analyzed between the pre-treatment and post-treatment T-PLL samples. After analysis, it was apparent that the Jak-Stat gene set was significantly enriched (p-value 0.006 and FDR of 0.068) in the pre-treatment T-PLL samples when compared to the post-treatment samples. The p53 gene and p53 pathway genes were transcriptionally upregulated, but did not reach statistical significance. Q-RT PCR validation studies were conducted. One patient had a 5 fold increase in p53 mRNA and another had a 13 fold increase in DUSP2 mRNA (Fig. 2), a phosphatase that is a downstream target of p53. P53 has been not thought to be epigenetically regulated before a recent paper utilizing adenovirus in cultured cells. These results demonstrate that resistance to monoclonal antibody antitumor effects can be overcome with epigenetic agents. Correlative science data implicates the p53 gene pathway in mediating monoclonal antibody induced antileukemia effects in PLL, and imply that inhibition of Jak-Stat signaling may also play a role in these cells. We also demonstrate epigenetic regulation of p53 and a downstream target gene (DUSP2) that correlates with response to alemtuzumab. Furthermore, our data suggests that the combination of epigenetic agents with monoclonal antibodies should be studied and that epigenetic agents are potentially capable of activating multiple silenced genes in different pathways. A prospective, multicenter trial of alemtuzumab, cladribine, with or without an HDACi in newly diagnosed and relapsed PLL is warranted. [Display omitted] Disclosures:Epner:Merck: Consultancy, Honoraria, Speakers Bureau; Novartis: Speakers Bureau; Millenium: Speakers Bureau; Allos: Speakers Bureau; Enzon: Speakers Bureau; GSK: Speakers Bureau.

A case of T cell prolymphocytic leukemia involving blast transformation

We report a case of T cell prolymphocytic leukemia (T-PLL) involving blast transformation. At the initial diagnosis, most peripheral blood cells demonstrated proliferation of indolent T cell small cell variants, i.e., small to medium prolymphocytes with inconspicuous nucleoli and a normal karyotype. These cells were positive for surface CD4, CD5, and CD7, and cytoplasmic CD3, but negative for surface CD3 and CD8 and cytoplasmic terminal deoxynucleotidyl transferase (TdT). The T cell receptor (TCR) Cβ1 gene was rearranged in the cells. Large prolymphocytes with prominent nucleoli, irregular nuclei, and cytoplasmic vacuoles that exhibited chromosome 8 trisomy were observed about 1.5 years later. The CD4+CD8- single positive effector memory T cells transformed into surface CD4+CD8+ double positive precursor T cells. The clonal TCR gene rearrangement patterns of these cells were identical throughout the clinical course, suggesting clonal blast transformation. The CD4+CD8+ cells demonstrated increased chromosome 8 trisomy combined with complex chromosome abnormalities with t(14;14)(q11.2;q32) containing a 14q32 chromosome after transformation. T cell leukemia 1a (TCL1a) (14q32.1) may be implicated in this case. The TCL1a oncoprotein is expressed in approximately 70% of T-PLL cases. The disease gradually developed resistance to chemotherapy, and the patient died of the disease. It is known that indolent T-PLL can become aggressive. Therefore, similar transformations may occur in other aggressive T-PLL cases, particularly those involving trisomy 8 and TCL1a.

LEUCÉMIE PROLYMPHOCYTAIRE DE PHÉNOTYPE B DE MAUVAIS PRONOSTIC

Introduction : B cell prolymphocytic leukemia is a rare disease with poor prognosis compared with chronic lymphocytic leukemia. Case report : Patient aged 75 years old, diabetic and hypertensive, with a massive splenomegaly associated with leukocytosis exceeding 100000/mm3 predominantly prolymphocytic, invading the bone marrow. Immunophenotyping showed CD19 +, CD20 +, CD22 +, CD5 part, CD23+ CD79b + FMC7 stronger and stronger, Smg + in vafour for a type B-cell prolymphocytic leukemia. The evolution was rapidly unfavorable despite an first line treatment of eight cycles of COP (cyclophosphamide, vincristine and prednisone). Partial remission was short, followed by the reappearance of the splanomegaly, new increase in the of Prolymphocyte tate with thrombocytopenia and profound anemia. The patient had received two courses of Fludarabine. Dath occurred after eighteen months of follow up due to a state of septic shock and tumor lysis syndrome. Discussion : This malignancy accounts for 2% of all chronic lymphocytic leukemia with 80% phenotype B. It frequently affects patients of 70 years old with a clear male predominance. The prognosis is more severe than that of chronic lymphocytic leukemia. Anemia 100000/mm3 are the factors of poor prognosis. The median survival was 65 months reported by Shvidel et al. in a series of 35 observations. Conclusion : Promising results are reported with new treatments. The antibady anti-CD20 has been used successfully for the second type of B-cell prolymphocytic leukemia after relapse. The allograft or autograft are indicated, but it is mostly used in patients, who have contraindications to a heavy treatment.