Current and upcoming treatment approaches to uncommon subtypes of PTCL (EATL/MEITL, SPTCL, HSTCL).

Rare subtypes of peripheral T-cell lymphoma (PTCL) including enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), subcutaneous panniculitis-like T-cell lymphoma (SPTCL) and hepatosplenic T-cell lymphoma (HSTCL) are underrepresented in most registry and clinical studies. Most of the literature is obtained from small case series, single-institution retrospective studies and subgroup analyses of the largest studies with few recent and ongoing exceptions. While the pathogenesis and biology of these entities have yet to be fully elucidated, global efforts by the scientific community have started to shed some light on the most frequently deregulated pathways. In this review, we highlight the most pertinent clinical and pathologic features of rare subtypes of PTCL including EATL/MEITL, SPTCL and HSTCL. We also summarize the results of recent developments identifying potential targets for novel therapeutic strategies based on molecular studies. Finally, we highlight the underrepresentation of these rare subtypes in most clinical trials, making evidence-based therapeutic decisions extremely challenging.

CD19-Targeted Chimeric Antigen Receptor T-cell Therapy for Concomitant Diffuse Large B-cell Lymphoma and Multiple Myeloma.

Multiple myeloma (MM) and diffuse large B-cell lymphoma (DLBCL) comprise a large fraction of hematologic malignancies diagnosed each year. However, the co-occurrence of these conditions in the same patient is rare. CD19- and B-cell maturation antigen-targeted chimeric antigen receptor (CAR) T-cell therapies have been approved in recent years with promising responses. Here, we present a patient who presented following a bone marrow biopsy that revealed MM with 20% lambda-restricted plasma cells with no evidence of lymphoma involvement in the marrow. A subsequent lymph node biopsy of a right thigh mass was done and revealed DLBCL. The patient received CD19-targeted CAR T-cell therapy and has no detectable MM or DLBCL. To our knowledge, this is the first case report in the literature describing a patient with concomitant MM and DLBCL who received CD19-targeted CAR T-cell therapy.

Idiopathic CD4+ T-lymphocytopaenia with FLT1 mutation complicated by progressive multifocal leucoencephalopathy and EBV+ polymorphic lymphoproliferative disorder.

We describe a unique case of idiopathic CD4+T cell lymphocytopaenia complicated by viral-associated disorders in a patient with a heterozygous FLT1 mutation. A previously healthy woman presented with left-sided neurological deficits. Workup revealed a severe HIV-seronegative CD4+T cell deficiency and white matter brain lesions; brain biopsy confirmed progressive multifocal leucoencephalopathy (PML). Six years later, she represented with a tender mandibular lesion, with pathology diagnostic for EBV+polymorphic post-transplant-like lymphoproliferative disorder. A heterozygous FLT1 P1127L mutation was detected on peripheral blood and mandibular lesion next-generation sequencing. Concern for PML reactivation with rituximab-based therapy and the presence of localised disease led us to offer radiotherapy, resulting in significant symptom relief and marked therapeutic response on repeat imaging.

Acute cardiomyopathy following a single dose of doxorubicin in a patient with adult T-Cell leukemia/lymphoma.

INTRODUCTION: Anthracycline-based chemotherapy regimens are associated with decreased cardiac function with cumulative dosing, yet there is limited information regarding the acute cardiotoxic potential of these medications and appropriate medical management strategies. Herein, we report a case of cardiomyopathy following a single dose of doxorubicin and describe our pharmacologic management approach. CASE REPORT: A 37 year old Jamaican male presented for work-up and treatment of HTLV-1 associated T-cell leukemia/lymphoma. Upon diagnosis, the patient received one cycle of CHOEP, which was complicated by tumor lysis syndrome. Subsequently, the treatment was changed to DA-EPOCH, however, immediately after the initiation of DA-EPOCH on day 1, the patient was found to have t-wave inversions on EKG and an ejection fraction (EF) of 20% with new mitral regurgitation. EPOCH infusion was discontinued within 3 hours of initiation.Management and outcome: The chemotherapy regimen was modified to DA-EPOC with the removal of doxorubicin. The patient was started on metoprolol succinate 12.5 mg once daily for 2 days and subsequently switched to carvedilol 3.125 mg twice daily and lisinopril 5 mg once daily; the patient's ejection fraction improved to baseline after 2.5 months of therapy. DISCUSSION: Though anthracyclines are associated with cardiotoxicity at high cumulative doses, this case highlights the cardiotoxic potential of these medications in the acute setting. Management of anthracycline cardiotoxicity is similar to heart failure management, with data suggesting benefit of using carvedilol and lisinopril. It is unclear if our patient would have benefited from prophylactic angiotensin converting enzymes inhibitors (ACEi) and/or beta-blocker therapy, as he had no known cardiac disease. Acute anthracycline-induced cardiac toxicity is an adverse drug reaction with which providers should be familiar and know how to appropriately manage.

N-quinoline-benzenesulfonamide derivatives exert potent anti-lymphoma effect by targeting NF-κB.

We previously identified the N-quinoline-benzenesulfonamide (NQBS) scaffold as a potent inhibitor of nuclear factor-κB (NF-κB) translocation. Now, we report the structure-activity relationship of compounds with the NQBS scaffold in models of diffuse large B-cell lymphoma (DLBCL). We identified CU-O42, CU-O47, and CU-O75 as NQBS analogs with the most potent cytotoxic activity in DLBCL lines. Their anti-lymphoma effect was mediated by NF-κB sequestration to the cytoplasm of DLBCL cells. Internal Coordinates Mechanics analysis suggested direct binding between CU-O75 and IκBα/p50/p65 which leads to the stabilization of the NF-κB trimer. A whole cellular thermal shift assay confirmed direct binding of the NQBS to IκBα, an inhibitory component of the IκBα/p50/p65 trimer. Lymphoma cell line sequencing revealed CU-O75 induced downregulation of NF-κB-dependent genes and DeMAND analysis identified IκBα as one of the top protein targets for CU-O75. CU-O42 was potent in inhibiting tumor growth in two mouse models of aggressive lymphomas.

Reversal of CYLD phosphorylation as a novel therapeutic approach for adult T-cell leukemia/lymphoma (ATLL).

Adult T-cell leukemia/lymphoma (ATLL) is a malignancy of mature T cells associated with chronic infection by human T-cell lymphotropic virus type-1 (HTLV-1). ATLL patients with aggressive subtypes have dismal outcomes. We demonstrate that ATLL cells co-opt an early checkpoint within the tumor necrosis factor receptor 1 (TNFR1) pathway, resulting in survival advantage. This early checkpoint revolves around an interaction between the deubiquitinase CYLD and its target RIPK1. The status of RIPK1 K63-ubiquitination determines cell fate by creating either a prosurvival signal (ubiquitinated RIPK1) or a death signal (deubiquitinated RIPK1). In primary ATLL samples and in cell line models, an increased baseline level of CYLD phosphorylation was observed. We therefore tested the hypothesis that this modification of CYLD, which has been reported to inhibit its deubiquitinating function, leads to increased RIPK1 ubiquitination and thus provides a prosurvival signal to ATLL cells. CYLD phosphorylation can be pharmacologically reversed by IKK inhibitors, specifically by TBK1/IKKε and IKKß inhibitors (MRT67307 and TPCA). Both of the IKK sub-families can phosphorylate CYLD, and the combination of MRT67307 and TPCA have a marked effect in reducing CYLD phosphorylation and triggering cell death. ATLL cells overexpressing a kinase-inactive TBK1 (TBK1-K38A) demonstrate lower CYLD phosphorylation and subsequently reduced proliferation. IKK blockade reactivates CYLD, as evidenced by the reduction in RIPK1 ubiquitination, which leads to the association of RIPK1 with the death-inducing signaling complex (DISC) to trigger cell death. In the absence of CYLD, RIPK1 ubiquitination remains elevated following IKK blockade and it does not associate with the DISC. SMAC mimetics can similarly disrupt CYLD phosphorylation and lead to ATLL cell death through reduction of RIPK1 ubiquitination, which is CYLD dependent. These results identify CYLD as a crucial regulator of ATLL survival and point to its role as a potential novel target for pharmacologic modification in this disease.

Brentuximab vedotin plus bendamustine in relapsed or refractory Hodgkin's lymphoma: an international, multicentre, single-arm, phase 1-2 trial.

BACKGROUND: Brentuximab vedotin is currently approved for patients with relapsed or refractory Hodgkin's lymphoma who previously received an autologous stem cell transplant or two previous multiagent chemotherapy regimens, and for patients with relapsed or refractory systemic anaplastic large-T-cell lymphoma who previously received at least one chemotherapy regimen. A high proportion of patients with CD30-expressing relapsed or refractory lymphomas have durable responses to single-agent brentuximab vedotin and show longer progression-free survival than do patients treated with chemotherapy. In patients with Hodgkin's lymphoma and peripheral T-cell lymphoma, treatment with bendamustine alone only achieves modest improvements in progression-free survival compared with that for chemotherapy. The objective of this study was to explore the safety and clinical activity of the combination of brentuximab vedotin plus bendamustine in heavily pretreated patients with relapsed or refractory Hodgkin's lymphoma and anaplastic large-T-cell lymphoma. METHODS: In this international, multicentre, single-arm, phase 1-2 trial, eligible patients were aged 18 years or older, had histologically confirmed relapsed or refractory Hodgkin's lymphoma or anaplastic large-T-cell lymphoma, had biopsy-proven CD30-positive tumours, had an Eastern Cooperative Oncology Group performance status of 2 or less, and received at least one previous multiagent chemotherapy regimen. In phase 1, patients were assigned following a 3+3 dose-escalation design to one of four cohorts to receive one dose of either 1·2 mg/kg or 1·8 mg/kg of brentuximab vedotin intravenously on day 1 of a 21 day cycle, plus one dose of bendamustine (70 mg/m2, 80 mg/m2, or 90 mg/m2) on days 1 and 2 of the treatment cycle. In phase 2, all patients were assigned to receive brentuximab vedotin plus bendamustine at the recommended phase 2 dose from phase 1. The primary endpoints were maximum tolerated dose and dose-limiting toxicity for phase 1, and the proportion of patients achieving an overall response in phase 2. For both phases 1 and 2, all patients receiving at least one dose of study drug were evaluable for toxicity and all patients completing at least one cycle of therapy were evaluable for response. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT01657331. FINDINGS: Between July 26, 2012, and May 31, 2017, we enrolled and assigned 65 patients to treatment (64 [98%] with Hodgkin's lymphoma and one [2%] with anaplastic large-T-cell lymphoma; 28 [43%] during phase 1 and 37 [57%] during phase 2). In the phase 1 part, the maximum tolerated dose of the combination was not reached. Dose-limiting toxicities were observed in three (11%) of 28 patients, including grade 4 neutropenia at 1·8 mg/kg brentuximab vedotin plus 80 mg/m2 of bendamustine in two (7%) patients and diffuse rash at 1·2 mg/kg brentuximab vedotin plus 70 mg/m2 of bendamustine in one (4%) patient. The recommended phase 2 dose was deemed to be 1·8 mg/kg of brentuximab vedotin and 90 mg/m2 of bendamustine, which are the standard doses of the drugs when given as single agents. In the phase 2 part, an overall response was achieved in 29 (78% [95% CI 62-91]) of 37 patients. Serious adverse events included grade 3 lung infection in five (14%) of 37 patients in the phase 2, and grade 3-4 neutropenia in 16 (25%) of 65 patients across phases 1 and 2. There were no treatment-related deaths. INTERPRETATION: This study shows that brentuximab vedotin plus bendamustine, with a favourable safety profile, is an active salvage regimen for heavily pretreated patients with relapsed or refractory Hodgkin's lymphoma. This salvage regimen can potentially serve as an efficacious and safe alternative to platinum-based chemotherapy before autologous stem cell transplant. FUNDING: Seattle Genetics, Lymphoma Research Fund of Columbia University and National Center for Advancing Translational Sciences, and National Institutes of Health.

A phase 1 study of romidepsin and pralatrexate reveals marked activity in relapsed and refractory T-cell lymphoma.

Peripheral T-cell lymphomas (PTCL) are a group of rare malignancies characterized by chemotherapy resistance and poor prognosis. Romidepsin and pralatrexate were approved by the US Food and Drug Administration for patients with relapsed/refractory PTCL, exhibiting response rates of 25% and 29% respectively. Based on synergy in preclinical models of PTCL, we initiated a phase 1 study of pralatrexate plus romidepsin in patients with relapsed/refractory lymphoma. This was a single institution dose-escalation study of pralatrexate plus romidepsin designed to determine the dose-limiting toxicities (DLTs), maximum tolerated dose, pharmacokinetic profile, and response rates. Patients were treated with pralatrexate (10 to 25 mg/m2) and romidepsin (12 to 14 mg/m2) on 1 of 3 schedules: every week × 3 every 28 days, every week × 2 every 21 days, and every other week every 28 days. Treatment continued until progression, withdrawal of consent, or medical necessity. Twenty-nine patients were enrolled and evaluable for toxicity. Coadministration of pralatrexate and romidepsin was safe, well tolerated, with 3 DLTs across all schedules (grade 3 oral mucositis × 2; grade 4 sepsis × 1). The recommended phase 2 dose was defined as pralatrexate 25 mg/m2 and romidepsin 12 mg/m2 every other week. Twenty-three patients were evaluable for response. The overall response rate was 57% (13/23) across all patients and 71% (10/14) in PTCL. The phase 1 study of pralatrexate plus romidepsin resulted in a high response rate in patients with previously treated PTCL. A phase 2 study in PTCL will determine the efficacy of the combination. This trial was registered at www.clinicaltrials.gov as #NCT01947140.

An Update on the Use of Immunotherapy in the Treatment of Lymphoma.

PURPOSE OF REVIEW: Throughout the field of oncology, immunotherapy is moving further towards the first-line setting, and there is encouraging data for the use of these novel therapies in the management of lymphomas, utilizing treatments approved for both solid and hematologic malignancies. Herein, we review promising advances in this rapidly moving field from the past year. RECENT FINDINGS: In the last year, we have seen promising clinical data on engineered antibody therapies for the treatment of lymphomas, as well as further optimization of engineered antibody fragments fused onto linkers or chimeric T cell receptors, both of the modalities capable of transforming non-specific T cells into tumor-specific, serial killer cells. Here we will review the promising data on these advances in antibody-based therapies, as well as some of the immunomodulators and checkpoint-blocking therapies that shown to have promising results in the treatment of lymphomas within the past year.

The combination of hypomethylating agents and histone deacetylase inhibitors produce marked synergy in preclinical models of T-cell lymphoma.

T-cell lymphomas (TCL) are aggressive lymphomas usually treated with CHOP (cyclophsophamide, doxorubicin, vincristine, prednisolone)-like regimens upfront. Recent data suggest that TCL are driven by epigenetic defects, potentially rendering them sensitive to epigenetic therapies. We explored the therapeutic merits of a combined epigenetic platform using histone deacetylase inhibitors (HDACIs) and DNA methyltransferase inhibitors (DNMT) in in vitro and in vivo models of TCL. The 50% inhibitory concentration (IC50 ) values revealed romidepsin was the most potent HDACI, with an IC50 in the low nanomolar range. The combination with a hypomethylating agent produced synergy across all cell lines, which was confirmed in cytotoxicity and apoptosis assays. An in vivo xenograft study demonstrated inhibition of tumour growth in the combination cohort compared to the single agent. Gene expression array and global methylation profiling revealed differentially expressed genes and modulated pathways for each of the single treatment conditions and the combination. Most of the effects induced by the single agent treatment were maintained in the combination group. In total, 944 unique genes were modulated by the combination treatment, supporting the hypothesis of molecular synergism. These data suggest combinations of hypomethylating agents and HDACIs are synergistic in models of TCL, which is supported at the molecular level.

Sirtuin and pan-class I/II deacetylase (DAC) inhibition is synergistic in preclinical models and clinical studies of lymphoma.

Understanding the molecular pathogenesis of lymphoma has led to paradigm-changing treatment opportunities. One example involves tailoring specific agents based on the cell of origin in aggressive lymphomas. Germinal center (GC)-derived diffuse large B-cell lymphoma (DLBCL) is known to be driven by an addiction to Bcl6, whereas the activated B-cell (ABC) subtype is driven by nuclear factor κB. In the GC subtype, there is a critical inverse relationship between Bcl6 and p53, the functional status of which is linked to each transcription factor's degree of acetylation. Deacetylation of Bcl6 is required for its transcriptional repressor effects allowing for the oncogene to drive lymphomagenesis. Conversely, acetylation of p53 is activating when class III deacetylases (DACs), or sirtuins, are inhibited by niacinamide. Treatment of DLBCL cell lines with pan-DAC inhibitors in combination with niacinamide produces synergistic cytotoxicity in GC over ABC subtypes. This correlated with acetylation of both Bcl6 and p53. This combination also produced remissions in a spontaneous aggressive B-cell lymphoma mouse model expressing Bcl6. In a phase 1 proof-of-principle clinical trial, 24% of patients with relapsed or refractory lymphoma attained a response to vorinostat and niacinamide, and 57% experienced disease stabilization. We report herein on the preclinical and clinical activity of this targeted strategy in aggressive lymphomas. This trial was registered at www.clinicaltrials.gov as #NCT00691210.

Propolis and its Active Component, Caffeic Acid Phenethyl Ester (CAPE), Modulate Breast Cancer Therapeutic Targets via an Epigenetically Mediated Mechanism of Action.

Alternative remedies for cancer treatment is a multi-billion dollar industry. In particular, breast cancer (BC) patients use alternative and natural remedies more frequently than patients with other malignancies. Propolis is an example of a honeybee-produced naturopathic formulation, contents of which differ by geographic location. It is readily available, affordable, and in use safely since ancient times globally. Caffeic acid phenethyl ester (CAPE) is a major active component in propolis and is thought to be responsible for its varied properties, including antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory and anticancer. CAPE is effective in many models of human cancer, including BC as we have previously shown. CAPE affects genes associated with tumor cell growth and survival, angiogenesis and chemoresistance. We demonstrate that these are related in part to CAPE's role as a histone deacetylase inhibitor, a class of drugs designated as epigenetic agents that modulate the activities of oncogenes and tumor suppressor genes. CAPE and propolis, cause an accumulation of acetylated histone proteins in MCF-7 (ER+) and MDA-MB-231 (ER-/PR-/Her2-) cells with associated decreases in ER and PR in MCF-7 cells, and upregulation of ER and decrease in EGFR in MDA-231 cells. In addition, these products reduced activated phosphorylated Her2 protein in SKBR3 (Her2 +) cells. Interestingly, propolis, when normalized for CAPE content, appears to be more potent than CAPE alone similarly to the greater effects of complete foods than isolated components. These data provide a potential mechanistic basis for one of the oldest naturopathic agents used in medicine and cancer treatment.

Development and characterization of a novel CD19CherryLuciferase (CD19CL) transgenic mouse for the preclinical study of B-cell lymphomas.

PURPOSE: To generate a transgenic mouse that when crossed with spontaneous mouse models of lymphoma will allow for quantitative in vivo measurement of tumor burden over the entire spectrum of the disease and or response to therapy in a "disease" or lymphoma subtype-specific manner. EXPERIMENTAL DESIGN: We developed a novel genetically engineered transgenic mouse using a CherryLuciferase fusion gene targeted to the CD19 locus to achieve B-cell-restricted fluorescent bioluminescent emission in transgenic mouse models of living mice. The use of a dual function protein enables one to link the in vivo analysis via bioluminescence imaging to cell discriminating ex vivo analyses via fluorescence emission. RESULTS: The spatiotemporal tracking of B-cell lymphoma growth and the response of an established B-cell lymphoma to a drug known to induce remission was evaluated in a double transgenic animal obtained by crossing the CD19CherryLuciferase transgenic mouse to a mouse model of an aggressive B-cell lymphoma. The observations validated the use of the CD19CherryLuciferase transgenic mouse in the assessment of an active drug routinely used in the treatment of lymphoproliferative malignancies. CONCLUSIONS: The transgenic mouse described here is the first of its kind, intended to be used to hasten translational studies of novel agents in lymphoma, with the intent that understanding the relevant pharmacology before clinical study will accelerate successful development in clinical studies.

HDAC inhibitors and decitabine are highly synergistic and associated with unique gene-expression and epigenetic profiles in models of DLBCL.

Interactions between histone deacetylase inhibitors (HDACIs) and decitabine were investigated in models of diffuse large B-cell lymphoma (DLBCL). A number of cell lines representing both germinal center B-like and activated B-cell like DLBCL, patient-derived tumor cells and a murine xenograft model were used to study the effects of HDACIs and decitabine in this system. All explored HDACIs in combination with decitabine produced a synergistic effect in growth inhibition and induction of apoptosis in DLBCL cells. This effect was time dependent, mediated via caspase-3 activation, and resulted in increased levels of acetylated histones. Synergy in inducing apoptosis was confirmed in patient-derived primary tumor cells treated with panobinostat and decitabine. Xenografting experiments confirmed the in vitro activity and tolerability of the combination. We analyzed the molecular basis for this synergistic effect by evaluating gene-expression and methylation patterns using microarrays, with validation by bisulfite sequencing. These analyses revealed differentially expressed genes and networks identified by each of the single treatment conditions and by the combination therapy to be unique with few overlapping genes. Among the genes uniquely altered by the combination of panobinostat and decitabine were VHL, TCEB1, WT1, and DIRAS3.

[Autologous stem cell transplantation in patients with relapsed or refractory Hodgkin's disease]. / Transplantacija autolognih krvotvornih maticnih stanica u bolesnika s relapsom ili refraktornim Hodgkinovim limfomom.

Patients with relapsed or refractory Hodgkin's disease (HD) are routinely treated with intensive chemotherapy followed by autologous stem cell transplantation (ASCT). The objectives of the study were to evaluate ASCT in this subset of patients by assessing its toxicity in terms of transplant related mortality (TRM), hematopoietic recovery and need for transfusion support, and efficacy in terms of complete remission (CR) achieved as well as long-term efficacy expressed in patient overall survival (OS). From February 1995 until October 2006, a total of 53 patients with active HD (28 male and 25 female, aged 18-60, median 29) received BEAM myeloablative treatment followed by ASCT. All patients received heavy prior treatment with a median of 2 different lines of chemotherapy (range 1-6) and a median of 8 chemotherapeutic cycles (range 2-15). A mean of 9.12 (range 1.03-32.6, SD 9.5) x 10(6)/kg CD34+ cells was reinfused, followed by filgrastim (median 8 days, range 4-22 days). The median time to WBC recovery (> 1 x 10(9)/L) was 10 (range 2-26) days, while platelets recovered (> 20 x 10(9)/L) in a median of 10 (range 4-30) days. During the post-transplant period, a mean of 16.3 platelet doses (range 0-77, SD 15.5) and 345.6 mL of RBC concentrate (range 0-1990, SD 478.4) was administered. A median of 3 febrile days (range 0-20) was observed. Of all patients, 43 (81.1%) achieved CR and 9 (17.0%) achieved partial remission. One patient died during the pancytopenic period (TRM 1.9%). The projected overall survival is 66.3% at 3948 days. Accordingly, in this group of patients with active disease at the time of transplantation, ASCT toxicity could be considered acceptable. A very high remission rate was achieved (CR+PR 98.1%). We conclude that BEAM myeloablative chemotherapy followed by ASCT is a very efficacious treatment for patients with relapsed or refractory HD.

New drugs for the treatment of lymphoma.

Historically, most drugs developed for treatment of leukemias, lymphomas, and myeloma had already been studied in the solid tumor setting. Nearly 10 years ago, chronic myelogenous leukemia (CML) forever changed this paradigm. Imatinib showed that it was possible to nullify the pathognomic genetic lesion in a hematologic malignancy. Since the approval of imatinib for CML, a host of new drugs active in blood cancers have emerged. This article highlights some areas of innovative drug development in lymphoma where possible; it emphasizes the biologic basis for the approach, linking this essential biology to the biochemical pharmacology. The article focuses on the many new targets including Syk, Bcl-2, CD-40, and the phosphoinositide-3 kinase/AKT/mammalian target of rapamycin pathway.

[The disappearance of CD20 positive lymphocytes in the pleural effusion after intrapleural application of rituximab]. / Nestanak CD20 pozitivnih limfocita iz pleuralnog izljeva nakon intrapleuralne primjene rituksimaba u bolesnice s folikularnim limfomom.

A 63 year old woman with non-Hodgkin lymphoma presented with unilateral pleural effusion, which when aspirated revealed CD19 and CD20 positive malignant cells. Prior to this, the patient had received several lines of chemotherapy (CHOP, VAD, FED) with no effect on pleural effusion. Repeated percutaneous drainage procedures were unable to control the effusion either. Rituximab was therefore instilled in a dose escalating manner via repeated pleurocenteses. Fifty days after the application of rituximab, pleural effusion was still present but reduced in size. Flow cytometry and immunocytochemistry performed on the same day showed CD19 positive cells which were lacking CD20 epitope, which could be explained by either engagement or destruction of the CD20 epitope upon interaction with rituximab making the detection of the CD20 molecule impossible by routine flow cytometry. What is especially interesting is the fact that even 50 days after the application of rituximab intrapleurally no new CD20 positive cells could be found in the pleural effusion by immunochemistry or flow cytometry, opening an interesting issue concerning the length of rituximab's activity when applied locally. Although our patient had no adverse effects, further analysis of rituximab's activity and safety when applied intrapleurally is warranted.

A critical appraisal of conventional and investigational drug therapy in patients with hypereosinophilic syndrome and clonal eosinophilia.

Hypereosinophilic syndrome (HES) is a rare disorder characterized by persistent and marked eosinophilia, leading to end-organ damage. Over the last decade, great progress has been made in unraveling the molecular basis of HES that has resulted in the characterization of specific genetic alterations linked to clonal eosinophilia. The most frequently encountered genetic aberrancy is the cryptic FIP1-like 1/platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) fusion transcript, which results in an eosinophilic, myeloproliferative disorder. In addition, in a subset of patients with HES, a population of aberrant T cells that secretes interleukin-5 can be identified, indicating the existence of lymphocyte-mediated hypereosinophilia. These new insights have led to both a genetically based (re)classification of eosinophilic blood disorders and to effective therapies with targeted agents, such as small-molecule tyrosine kinase inhibitors (eg, imatinib, nilotinib, PKC412) and, more recently, monoclonal antibodies (eg, mepolizumab, alemtuzumab). These targeted therapies hold great promise for improving the clinical outcomes of patients with HES and clonal eosinophilia, and they have exhibited relatively safe toxicity profiles.