Drugs Targeting CD20 in Multiple Sclerosis: Pharmacology, Efficacy, Safety, and Tolerability.

Currently, there are four monoclonal antibodies (mAbs) that target the cluster of differentiation (CD) 20 receptor available to treat multiple sclerosis (MS): rituximab, ocrelizumab, ofatumumab, and ublituximab. B-cell depletion therapy has changed the therapeutic landscape of MS through robust efficacy on clinical manifestations and MRI lesion activity, and the currently available anti-CD20 mAb therapies for use in MS are a cornerstone of highly effective disease-modifying treatment. Ocrelizumab is currently the only therapy with regulatory approval for primary progressive MS. There are currently few data regarding the relative efficacy of these therapies, though several clinical trials are ongoing. Safety concerns applicable to this class of therapeutics relate primarily to immunogenicity and mechanism of action, and include infusion-related or injection-related reactions, development of hypogammaglobulinemia (leading to increased infection and malignancy risk), and decreased vaccine response. Exploration of alternative dose/dosing schedules might be an effective strategy for mitigating these risks. Future development of biosimilar medications might make these therapies more readily available. Although anti-CD20 mAb therapies have led to significant improvements in disease outcomes, CNS-penetrant therapies are still needed to more effectively address the compartmentalized inflammation thought to play an important role in disability progression.

Measurement of Trogocytosis: Quantitative Analyses Validated with Rigorous Controls.

Trogocytosis is a process in which receptors on acceptor cells remove and internalize cognate ligands from donor cells. Trogocytosis has a profound and negative impact on mAb-based cancer immunotherapy, as seen in the treatment of chronic lymphocytic leukemia (CLL) with CD20 mAbs, such as rituximab (RTX) and ofatumumab (OFA). Our clinical observations of RTX/OFA-mediated loss of the CD20 target from circulating CLL cells have been replicated in our in vitro studies. Here we describe flow cytometry and fluorescence microscopy experiments, which demonstrate that acceptor cells, such as monocytes/macrophages that express FcγR, remove and internalize both antigen and donor cell-bound cognate IgG mAbs for several different mAb-donor cell pairs. Fluorescent mAbs and portions of the plasma cell membrane are transferred from donor cells to acceptor cells, which include the THP-1 monocytic cell line as well as freshly isolated monocytes. We describe rigorous controls to validate the reactions and eliminate dissociation or internalization as alternative mechanisms. Trogocytosis is likely to contribute to neutropenia, thrombocytopenia, and liver damage associated with use of antibody-drug conjugates. The methods we have described should allow for examination of strategies focused on blocking trogocytosis and its adverse effects. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Trogocytosis of mAb-opsonized donor cells mediated by adherent THP-1 cells Alternate Protocol: Application of fluorescence microscopy to examine THP-1 cell-mediated trogocytosis Support Protocol 1: Alexa labeling of mAbs and determination of F/P ratios Support Protocol 2: Standard washing procedure Support Protocol 3: Labeling and opsonization of cells Basic Protocol 2: Trogocytosis mediated by human monocytes as acceptor cells Support Protocol 4: Isolation of human monocytes Basic Protocol 3: Trogocytosis mediated by THP-1 cells in solution Support Protocol 5: Retinoic acid treatment of THP-1 cells Support Protocol 6: Culturing of SCC-25, BT-474, MOLT-4 and THP-1 cell lines.

CD20+ T cells: an emerging T cell subset in human pathology.

INTRODUCTION: Although CD20 is classically a B cell marker, in the last three decades, dim expression has been noted on a subset of T cells as well that has been independently verified by a number of groups. Our understanding of these cells and their function is not well established. METHODS: A thorough review of original articles on CD20+ T cells was undertaken of Pubmed by using combination of phrases including "CD20+", "CD20-positive" and "T cells". Articles in English were considered, and there was no time restriction. RESULTS: CD20+ T cells express the standard T cell markers and, in comparison to CD20¯ T cells, appear to express greater inflammatory cytokines and markers of effector function. Although the ontogeny of these cells is still being established, the current theory is that CD20 may be acquired by trogocytosis from B cells. CD20+ T cells may be found in healthy controls and in a wide range of pathologies including autoimmune diseases, haematological and non-haematological malignancies and human immunodeficiency virus (HIV) infections. One of the best studied diseases where these cells are found is multiple sclerosis (MS) where a number of therapeutic interventions, including anti-CD20 depletion, have been shown to effectively deplete these cells. CONCLUSION: This review summarises the latest understanding of CD20+ T cells, their presence in various diseases, their putative function and how they may be an ongoing target of CD20-depleting agents. Unfortunately, our understanding of these cells is still at its infancy and ongoing study in a wider range of pathologies is required.

Linfomas no Hodgkin indolentes y terapia anti-CD20: una revisión de la literatura / Indolent non-Hodgkin's lymphomas and anti-CD20 therapy: a literature review

Introducción: Los linfomas no Hodgkin indolentes se destacan por el reto que suponen desde el punto de vista terapéutico. La introducción de la terapia con rituximab, un anticuerpo monoclonal que se une al antígeno CD20 de la membrana de los linfocitos B, revolucionó los tratamientos hasta ese momento y abrió el camino para el desarrollo de otros anticuerpos monoclonales anti-CD20. Objetivo: Describir las características generales de los linfomas no Hodgkin indolentes y de los anticuerpos monoclonales anti-CD20, así como el rol de la terapia anti-CD20 en dichas enfermedades. Métodos: Se realizó una revisión de la literatura publicada en los últimos 20 años, disponible en los repositorios: Scielo, Scopus, Pubmed/Medline, ScienceDirect y Mediagraphic. Se emplearon para elaborar este manuscrito 35 documentos, de ellos 80 por ciento correspondieron a los últimos 5 años. Conclusiones: La sólida evidencia científica, acumulada durante las últimas dos décadas, respalda el uso clínico de los anticuerpos monoclonales anti-CD20 en el tratamiento de los linfomas no Hodgkin indolentes. El uso efectivo de estos fármacos como agentes únicos o combinados con quimioterapia demuestran su versatilidad terapéutica(AU)

Introduction: Indolent non-Hodgkin's lymphomas are notable for the challenge they pose from a therapeutic point of view. The introduction of rituximab, a monoclonal antibody that binds to the CD20 antigen of the B-lymphocyte membrane, revolutionized treatments up to that time and opened the way for the development of other anti-CD20 monoclonal antibodies. Objective: To describe the general characteristics of indolent non-Hodgkin's lymphomas and anti-CD20 monoclonal antibodies, as well as the role of anti-CD20 therapy in these diseases. Methods: A review of the literature published in the last 20 years, available in the repositories: Scielo, Scopus, Pubmed/Medline, Science Direct and Mediagraphic, was performed. Thirty-five papers were used to prepare this manuscript, 80 percent of which corresponded to the last 5 years. Conclusions: Strong scientific evidence, accumulated over the last two decades, supports the clinical use of anti-CD20 monoclonal antibodies in the treatment of indolent non-Hodgkin's lymphomas. The effective use of these drugs as single agents or in combination with chemotherapy demonstrates their therapeutic versatility(AU)

Bispecific targeting of CD20 and CD19 increases polyfunctionality of chimeric antigen receptor T-cell products in B-cell malignancies.

BACKGROUND AIMS: Selective immune pressure contributes to relapse due to target antigen downregulation in patients treated with anti-CD19 chimeric antigen receptor (CAR) T cells. Bispecific lentiviral anti-CD20/anti-CD19 (LV20.19) CAR T cells may prevent progression/relapse due to antigen escape. Highly polyfunctional T cells within a CAR T-cell product have been associated with response in single-antigen-targeted anti-CD19 CAR T cells. METHODS: The authors performed a single-cell proteomic analysis to assess polyfunctional cells in our LV20.19 CAR T-cell product. Analysis was limited to those treated at a fixed dose of 2.5 × 106 cells/kg (n = 16). Unused pre-infusion CAR T cells were thawed, sorted into CD4/CD8 subsets and stimulated with K562 cells transduced to express CD19 or CD20. Single-cell production of 32 individual analytes was measured and polyfunctionality and polyfunctional strength index (PSI) were calculated. RESULTS: Fifteen patients had adequate leftover cells for analysis upon stimulation with CD19, and nine patients had adequate leftover cells for analysis upon stimulation with CD20. For LV20.19 CAR T cells, PSI was 866-1109 and polyfunctionality was 40-45%, which were higher than previously reported values for other CAR T-cell products. CONCLUSIONS: Stimulation with either CD19 or CD20 antigens resulted in similar levels of analyte activation, suggesting that this product may have efficacy in CD19- patient populations.

Dosimetric Approaches for Radioimmunotherapy of Non-Hodgkin Lymphoma in Myeloablative Setting.

Radioimmunotherapy (RIT) is a safe and active treatment available for non-Hodgkin lymphomas (NHLs). In particular, two monoclonal antibodies raised against CD20, that is Zevalin (90Y-ibritumomab-tiuxetan) and Bexxar (131I-tositumomab) received FDA approval for the treatment of relapsing/refractory indolent or transformed NHLs. RIT is likely the most effective and least toxic anticancer agent in NHLs. However, its use in the clinical setting is still debated and, in case of relapse after optimized rituximab-containing regimens, the efficacy of RIT at standard dosage is suboptimal. Thus, clinical trials were based on the hypothesis that the inclusion of RIT in myeloablative conditioning would allow to obtain improved efficacy and toxicity profiles when compared to myeloablative total-body irradiation and/or high-dose chemotherapy regimens. Standard-activity RIT has a safe toxicity profile, and the utility of pretherapeutic dosimetry in this setting can be disputed. In contrast, dose-escalation clinical protocols require the assessment of radiopharmaceutical biodistribution and dosimetry before the therapeutic injection, as dose constrains for critical organs may be exceeded when RIT is administered at high activities. The aim of the present study was to review and discuss the internal dosimetry protocols that were adopted for non-standard RIT administration in the myeloablative setting before hematopoietic stem cell transplantation in patients with NHLs.

Pharmacodynamics and molecular correlates of response to glofitamab in relapsed/refractory non-Hodgkin lymphoma.

Glofitamab, a novel CD20xCD3, T-cell-engaging bispecific antibody, exhibited single-agent activity in Study NP30179, a first-in-human, phase 1 trial in relapsed/refractory B-cell non-Hodgkin lymphoma. Preclinical studies showed that glofitamab leads to T-cell activation, proliferation, and tumor cell killing upon binding to CD20 on malignant cells. Here, we provide evidence of glofitamab's clinical activity, including pharmacodynamic profile, mode of action, and factors associated with clinical response, by evaluating biomarkers in patient samples from the dose-escalation part of this trial. Patients enrolled in Study NP30179 received single-dose obinutuzumab pretreatment (1000 mg) 7 days before IV glofitamab (5 µg-25 mg). Glofitamab treatment lasted ≤12 cycles once every 2 or 3 weeks. Blood samples were collected at predefined time points per the clinical protocol; T-cell populations were evaluated centrally by flow cytometry, and cytokine profiles were analyzed. Immunohistochemical and genomic biomarker analyses were performed on tumor biopsy samples. Pharmacodynamic modulation was observed with glofitamab treatment, including dose-dependent induction of cytokines, and T-cell margination, proliferation, and activation in peripheral blood. Gene expression analysis of pretreatment tumor biopsy samples indicated that tumor cell intrinsic factors such as TP53 signaling are associated with resistance to glofitamab, but they may also be interlinked with a diminished effector T-cell profile in resistant tumors and thus represent a poor prognostic factor per se. This integrative biomarker data analysis provides clinical evidence regarding glofitamab's mode of action, supports optimal biological dose selection, and will further guide clinical development. This trial was registered at www.clinicaltrials.gov as #NCT03075696.

A Method for the Elution of Anti-CD20 With an EDTA/Glycine Acid Solution for Accurate Immunophenotyping of B Lymphocytes Sensitized With Rituximab.

OBJECTIVES: To assess the efficacy of a method to circumvent CD20-positive antigen masking by rituximab for flow cytometry analysis of B-cell malignancies in hematology patients. METHODS: Mononuclear cells (MNCs) from 10 healthy individuals and 5 untreated patients with B-cell malignancies were sensitized with rituximab. Patients' diagnoses included chronic lymphocytic leukemia, hairy cell leukemia, and follicular lymphoma. MNCs were isolated by gradient density centrifugation. An EDTA/glycine acid (EGA) elution method was used to dissociate CD20-rituximab complexes; afterwards, CD20-positive immunoreactivity was assessed by flow cytometry. A saturation curve was built based on serial dilutions of rituximab. Median fluorescent intensities of CD20-positive signals were obtained before sensitization with rituximab and after its elution with EGA. RESULTS: CD20-positive signals were not detectable by flow cytometry after rituximab sensitization of B cells. CD20-sensitized vs CD20-unsensitized, CD20-sensitized vs CD20-eluted, and CD20-eluted vs CD20-negative control (NC) MNC populations exhibited statistical differences (P = .001), while CD20-sensitized vs CD20-NC populations did not (P = .499), confirming CD20 antigen masking by rituximab. CONCLUSIONS: Rituximab interfered with the flow cytometry protocol for CD20 determination on normal and neoplastic B cells. The EGA method efficiently eluted rituximab, allowing for accurate identification of CD20-positive B cells.

[Subendocardial injury with no evidence of atherosclerosis associated with obinutuzumab infusion]. / Injuria subendocárdica sin evidencia de aterosclerosis relacionada con infusión de obinutuzumab.

Obinutuzumab is a fully humanized monoclonal antibody against CD20 used in the treatment of chronic lymphocytic leukemia. Fatal cardiovascular events have been described, but only in patients with known cardiovascular records. We report the case of an adult male with a high-risk chronic lymphocytic leukemia who developed subendocardial injury, with no evidence of coronary atherosclerosis, during the first administration of obinutuzumab.

El obinutuzumab es un anticuerpo monoclonal completamente humanizado contra CD20, empleado en el tratamiento de leucemia linfocítica crónica. Los eventos cardiovasculares fatales han sido descritos, pero solo en pacientes con antecedentes cardiovasculares conocidos. Presentamos el caso de un hombre adulto con diagnóstico de leucemia linfocítica crónica de alto riesgo que desarrolló injuria subendocárdica, sin evidencia de aterosclerosis coronaria, durante la primera infusión de obinutuzumab.

The future of antibody therapy in chronic lymphocytic leukemia.

INTRODUCTION: Outcomes in chronic lymphocytic leukemia (CLL) have been dramatically improved with the addition of anti-CD20 antibodies to chemotherapy, defining a new standard of care for many years. More recently, therapies targeting fundamental signaling and anti-apoptotic pathways within the CLL cell have demonstrated dramatic clinical responses, including in patients with high-risk prognostic markers, thus emerging as preferred therapy for many patients. While the addition of anti-CD20 antibodies to traditional chemotherapy resulted in significant improvements in outcomes, the role of monoclonal antibodies in the era of targeted agents remains an active area of investigation. Furthermore, since the advent of next-generation anti-CD20 antibodies, the role of specific anti-CD20 antibodies remains an open question. AREAS COVERED: In this review, we highlight the important role that anti-CD20 antibody therapy has had in the field of CLL, both when used with chemotherapy and in combination with targeted therapy, as well as the current studies that are further exploring this treatment paradigm in the modern era. EXPERT OPINION: While anti-CD20 antibodies have played a pivotal role in the treatment of CLL, additional studies will be required to determine the optimal application of these therapies in combination with targeted therapy.

Reassessment of Anti-CD20 Therapy in Lymphoid Malignancies: Impact, Limitations, and New Directions.

The addition of anti-CD20 monoclonal antibodies to the treatment of B-cell malignancies has dramatically affected the field as well as the lives of patients. Rituximab in particular has been combined safely with conventional chemotherapy and has resulted in improved overall survival in major histologic subtypes of B-cell lymphoma and chronic lymphocytic leukemia. It is incorporated into the standard initial treatment of nearly all of these diseases. Novel anti-CD20 antibodies are currently under development. Two of these agents, ofatumumab and obinutuzumab, have been approved for use in certain clinical settings. Research comparing these newer antibodies with rituximab is ongoing. As these newer antibodies are further studied and developed, improvements in response and progression-free survival need to be considered in the context of clinical benefit as well as toxicity, especially in indolent diseases. Research involving rituximab biosimilars is ongoing as well, and recent preliminary data demonstrate similar efficacy and tolerability when compared with rituximab. An additional focus of ongoing research is the use of extended schedules of anti-CD20 monoclonal antibodies, as the optimal duration of therapy remains ill-defined in many histologic subtypes. To maximize the use of these agents, well-validated clinical trial endpoints will need to be carefully considered.

Converting Lymphoma Cells into Potent Antigen-Presenting Cells for Interferon-Induced Tumor Regression.

Anti-hCD20 is a therapeutic mAb that is clinically used to treat B-cell lymphoma. Some lymphomas are resistant to anti-hCD20; others relapse after treatment with anti-hCD20. Using a syngeneic immunocompetent mouse model, we observed that targeting lymphoma with interferon-α (IFNα) abolished resistance of B-cell lymphoma to anti-CD20 while limiting interferon (IFN)-associated systemic toxicity in the host. Control of tumors by a fusion of anti-CD20 and IFNα (anti-CD20-IFNα) depended on existing tumor-infiltrating CD8+ T cells. Although lymphomas were resistant to IFN-directed killing, IFN-exposed tumor cells became the dominant antigen-presenting cells (APC) for the reactivation of tumor-infiltrating CD8+ T cells that then controlled those lymphomas. Anti-CD20-IFNα also abolished checkpoint blockade resistance in advanced B-cell lymphoma. Our findings indicate that anti-CD20-IFNα eradicates B-cell lymphoma by employing tumor cells as APCs to reactivate tumor-infiltrating CD8+ T cells and synergizing with anti-PD-L1 treatment. Cancer Immunol Res; 5(7); 560-70. ©2017 AACR.

Eficacia y seguridad del uso de tofacitibini en el tratamiento de artritis reumatoide refractaria a Anti-TNF y Anti-CD20 / Efficacy and safety of the use of tofacitibini in the treatment of rheumatoid arthritis refractory to Anti-TNF and Anti-CD20

INTRODUCCIÓN: Antecedentes: El presente dictamen expone la evaluación de tecnología de la eficacia y seguridad tofacitinib en pacientes con artritis reumatoide con falla a tratamiento con anti-TNF y anti-CD20. Aspcetos Generales: La artritis reumatoide (AR) es un tipo de poliatritis periférica de naturaleza inflamatória y simétrica. Esta condición suele llevar a una deformación de las articulaciones a través de la erosión de cartilagos y hesos. La ausencia de un tratamiento eficaz, la inflamación y la destrucción de las articulaciones lleva la pérdida de las funciones motoras, y por tanto a la incapacidad de llevar a cabotareas cotidians, e incluso a dificuldades en el ámbito laboral. Tecnología Sanitaria de Interés: El tratamiento de AR incluye como prímera linea el uso de glucocorticoides y fármacos modificadores de la enfermedad (FARMEs) sintético. Si no se obtiene una respuesta adecuada con estos FARMEs sintéticos, es recomendable pasar al uso de agentes biológico, siendo los anti-TNF considerados como la primera opición por la alta tasa de respuesta asoiada a su uso. METODOLOGÍA: Estrategia de Búsqueda: Se realizó una búsqueda de literatura publicada sobre tofacitinib en el tratamiento de Artritis Reumatoide en las bases de datos: medline y Tripdabase. Adicionalmente, se realizaron búsquedas en los portales web de entidades que realizan revisiones sistemáticas, evaluaciones de tecnologías sanitarias y guías de práctica clínica: The Cochrane Library, National Institute for Helath and Care Excellence (NICE) del Reino Unido, American College of Rheumatology, European League Against Rheumatism, Revista Brasileira de Reumatologia, Canadian Agency for Drugs and Technologies in Health. RESUlTADOS: Sinopsis de la Evidencia: Guías de práctica Clínica: Se identificó una GPC de NICE del 2015 la cual redirecciona al lector hacia las evaluaciones de tecnología sanitaria publicadas por NICE sobre los diferentes agentes en el tratamiento de AR, las cuales fueron revisadas e incluidas en los resultados cuando fue pertinente. Evaluaciones de tecnología santiaria: Se incluyó en los resultados una revisión rápida de Canadian Agency for Drugs and Technologies in Health del 2015. Una ETS de NICE sobre tofacitinib se encuentra en desarrollo y se espera que esta sea publicada en el 2018. Revisiones sistemáticas con o sin meta-análisis: Se incluyó una revisión sistemática con meta-análisis de ensayos clínicos controlados, aleatorizados y doble ciego del 2013, y un análisis de data agregada del 2015. Adicionalmente, se incluyeron tres estudios que evaluaron únicamente seguridad: un análisis de dataagregada del 2014, un meta-análisis del 2015, y un análisis del 2017. Ensayos clínicos aleatorizados de fase III. Se incluyó en ECA de fase III del 2013. Adicionalmente, como sugerencia del especialista, se agregó un ECA de fase III del 2012. Resumen de congreso: A sugerencia del especialista se incluyó en los resultados un resumen del congreso del 2016. CONCLUSIONES: A la fecha no se han publicado ensayos clínicos aleatorizados del uso de tofacitinib en una población de pacientes con falla a tratamiento (primaria, secundaria o intolerancia) tanto a anti-TNFs como a anti-CD20. Las GPC identificadas presentan recomendaciones heterogéneas sobre el uso de tofacitinib. A pesar de ello, se puede concluir que, de acuerdo con las GPC, tofacitinib es considerado una alternativa tanto en pacientes que han fallado a tres o más tratamientos biológicos, como en aquellos que han fallado a uno; sin embargo, la mayoria de las GPC concuerdan en que el uso de tofacitinib se debe limitar a aquella población que ha agotado las opciones disponibles de tratamiento biológico, debido principalmente a la escasa información sobre el perfil de seguridad de tofacitinib y su efectos a largo plazo. Debido a que no es clara la relación riesgo/benefício y que existen otras alternativas que han probado ser eficaces para la misma condición (pacientes con AR con respuesta inadecuada a FARMEs biológicos) disponibles en el mercado peruano; a la fecha no se cuenta con evidencia que sustente que el uso de tofacitinib en la población de pacientes con respuesta inadecuada a mas de dos tratamientos biológicos suponga un benefício adicional al tratamiento utilizado actualmente, ni que se trate de un medicamento seguro para los pacientes. Asimismo, vale resaltar que las GPC internacionales identificadas mencionan otras posibles alternativas para la condición mencionada, e incluso algunas de ellas recomiendan otras alternativas por encima de tofacitinib, en línea con la preocupación ralacionada a su perfil de seguridad, y recomiendan reservar su uso únicamente para la población que ha agotado las opciones de tratamiento biológico disponibles en el mercado. El Instituto de Evaluación de Tecnologías en Salud e Investigación-IETSI, no aprueba el uso de tofacitinib en pacientes con AR que han fallado a tratamiento con anti-TNF y con anti-CD20.

Overcoming rituximab drug-resistance by the genetically engineered anti-CD20-hIFN-α fusion protein: Direct cytotoxicity and synergy with chemotherapy.

Treatment of patients with B-NHL with rituximab and CHOP has resulted in significant clinical responses. However, a subset of patients develops resistance to further treatments. The mechanism of unresponsiveness in vivo is not known. We have reported the development of rituximab-resistant clones derived from B-NHL cell lines as models to investigate the mechanism of resistance. The resistant clones exhibit hyper-activated survival/anti-apoptotic pathways and no longer respond to a combination of rituximab and drugs. Recent studies reported the therapeutic efficacy in mice bearing B-cell lymphoma xenografts following treatment with the anti-CD20-hIFNα fusion protein. We hypothesized that the fusion protein may bypass rituximab resistance and inhibit survival signaling pathways. Treatment of the rituximab-resistant clones with anti-CD20-hIFNα, but not with rituximab, IFNα, or rituximab+IFNα resulted in significant inhibition of cell proliferation and induction of cell death. Treatment with anti-CD20-hIFNα sensitized the cells to apoptosis by CDDP, doxorubicin and Treanda. Treatment with anti-CD20-hIFNα inhibited the NF-κB and p38 MAPK activities and induced the activation of PKC-δ and Stat-1. These effects were corroborated by the use of the inhibitors SB203580 (p38 MAPK) and Rottlerin (PKC-δ). Treatment with SB203580 enhanced the sensitization of the resistant clone by anti-CD20-hIFNα to CDDP apoptosis. In contrast, treatment with Rotterin inhibited significantly the sensitization induced by anti-CD20-hIFNα. Overall, the findings demonstrate that treatment with anti-CD20-hIFNα reverses resistance of B-NHL. These findings suggest the potential application of anti-CD20-hIFNα in combination with drugs in patients unresponsive to rituximab-containing regimens.

Primary central nervous system lymphoma: current state of anti-CD20 therapy and appraisal of reported response criteria.

Primary central nervous system lymphoma (PCNSL) is an aggressive non-Hodgkin's lymphoma which is confined to the central nervous system and may also affect intraocular structures. Despite high initial rates of response to methotrexate-based chemotherapy, more than 50% of patients will experience relapse and about 10% have disease that is refractory to chemotherapy. Outcome in patients who fail treatment is very poor, and therefore new therapeutic approaches that may increase the rate of complete response and the proportion of durable remission are sought. Based on the pivotal role that anti-CD20 therapy now plays in the treatment outcome of aggressive systemic B-cell lymphomas, a similar approach is commonly being adapted for PCNSL despite the lack of evidence for its effectiveness. This review examines the current status and level of evidence for the use of monoclonal antibodies against the CD20 surface antigen, which is present on normal and malignant B-cells in PCNSL. The review covers both systemic and local (intracerebrospinal fluid or intravitreal) administration of CD20 monoclonal antibodies in PCNSL. In addition, it scrutinizes the response criteria commonly reported for evaluation of treatment outcome. The importance of differentiating unconfirmed complete response from partial response is outlined and the lack of consensus on response criteria for atypical imaging presentations of PCNSL is delineated.

New potential therapeutic approach for the treatment of B-Cell malignancies using chlorambucil/hydroxychloroquine-loaded anti-CD20 nanoparticles.

Current B-cell disorder treatments take advantage of dose-intensive chemotherapy regimens and immunotherapy via use of monoclonal antibodies. Unfortunately, they may lead to insufficient tumor distribution of therapeutic agents, and often cause adverse effects on patients. In this contribution, we propose a novel therapeutic approach in which relatively high doses of Hydroxychloroquine and Chlorambucil were loaded into biodegradable nanoparticles coated with an anti-CD20 antibody. We demonstrate their ability to effectively target and internalize in tumor B-cells. Moreover, these nanoparticles were able to kill not only p53 mutated/deleted lymphoma cell lines expressing a low amount of CD20, but also circulating primary cells purified from chronic lymphocitic leukemia patients. Their safety was demonstrated in healthy mice, and their therapeutic effects in a new model of Burkitt's lymphoma. The latter serves as a prototype of an aggressive lympho-proliferative disease. In vitro and in vivo data showed the ability of anti-CD20 nanoparticles loaded with Hydroxychloroquine and Chlorambucil to increase tumor cell killing in comparison to free cytotoxic agents or Rituximab. These results shed light on the potential of anti-CD20 nanoparticles carrying Hydroxychloroquine and Chlorambucil for controlling a disseminated model of aggressive lymphoma, and lend credence to the idea of adopting this therapeutic approach for the treatment of B-cell disorders.

Biologics in oral medicine: ulcerative disorders.

Inflammatory ulcerative diseases of the oral mucosa are wide ranging but include especially aphthous and aphthous-like ulceration, vesiculobullous disorders and erosive lichen planus (LP). While most patients with these conditions respond to conventional topical and/or systemic immunosuppressive agents, treatment-resistant cases remain challenging. In these, the use of biologics such as tumour necrosis factor alpha (TNF-α) inhibitors or rituximab may be of benefit. This article reviews the use of biologics in ulcerative oral conditions, highlighting potential benefits, adverse effects and principles of use and future developments. TNF-α inhibitors such as infliximab can be effective in inducing resolution in oral aphthous and aphthous-like ulcers and may be an appropriate therapy in those patients in which disease is severe and refractory to, or patients are intolerant of, traditional immunomodulatory regimens. There would also seem support and rationale for use of biologics (mainly rituximab) in pemphigus but not in oral LP or other oral ulcerative conditions.

B-cell populations and sub-populations in Sjögren's syndrome.

Sjögren's Syndrome (SS) is a chronic inflammatory disorder affecting exocrine glands, in particular the lacrimal and salivary glands. The disease can be primary (pSS) or secondary to other systemic autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus and others. The systemic autoimmune character of pSS is also apparent from the occurrence of (non-organ specific) autoantibodies in this disease. Histopathologically, glandular involvement is characterized by focal accumulation of lymphocytes, particularly around epithelial ducts, with, sometimes, germinal center-like structures. The infiltrates largely consist of T-cells, with a preponderance of CD4-positive T-cells. As a result, the pathology in SS was primarily attributed to T cells. However, a break with the fixation on the role of T cells in pSS came when therapeutic B-cell depletion strategies proved remarkably efficacious in this disease, thereby indicating a major role for B-cells in the immunopathogenesis of pSS. In this regard, a closer look at the composition of B-cells and B-cell sub-populations, both in the peripheral blood and in target tissues, is worthwhile. In this review, we discuss current data on B-cells in pSS. B-cell depletion offers a unique possibility to study the recurrence of (pathogenic) B-cells and their characteristics in pSS patients treated with rituximab. Data on B-cell sub-populations in the peripheral blood and B-cell repertoire in the target tissues following rituximab treatment are discussed as well. We also address their state of activation, repertoire, and relation to B-cell activating factor (BAFF).

Chemoimmunotherapy in acute lymphoblastic leukemia.

ALL blast cells express a variety of specific antigens e.g. CD19, CD20, CD22, CD33, and CD52, which serve as targets for Monoclonal Antibodies (MoAbs). So far, the most experience is available for anti-CD20 (rituximab), which has been combined with chemotherapy for treatment of mature B-ALL/Burkitt's lymphoma. Studies with rituximab have also been completed in B-precursor ALL. Another antigen, CD19, is of great interest due to a very high rate of expression in ALL. It can be targeted by a bispecific monoclonal antibody, Blinatumomab, directed against CD19 and CD3. Smaller studies or case reports are also available for the anti CD52 antibody (Alemtuzumab), for anti CD22 (Epratuzumab) or anti CD33 (Gemtuzumab). Available data demonstrate that MoAb therapy in ALL is a highly promising targeted treatment. However, several details for an optimal treatment approach e.g. the required level of antigen expression, timing, schedule, dosage and stage of disease still need to be defined.

Anti-CD20 B-cell depletion enhances monocyte reactivity in neuroimmunological disorders.

BACKGROUND: Clinical trials evaluating anti-CD20-mediated B-cell depletion in multiple sclerosis (MS) and neuromyelitis optica (NMO) generated encouraging results. Our recent studies in the MS model experimental autoimmune encephalomyelitis (EAE) attributed clinical benefit to extinction of activated B-cells, but cautioned that depletion of naïve B-cells may be undesirable. We elucidated the regulatory role of un-activated B-cells in EAE and investigated whether anti-CD20 may collaterally diminish regulatory B-cell properties in treatment of neuroimmunological disorders. METHODS: Myelin oligodendrocyte glycoprotein (MOG) peptide-immunized C57Bl/6 mice were depleted of B-cells. Functional consequences for regulatory T-cells (Treg) and cytokine production of CD11b+ antigen presenting cells (APC) were assessed. Peripheral blood mononuclear cells from 22 patients receiving anti-CD20 and 23 untreated neuroimmunological patients were evaluated for frequencies of B-cells, T-cells and monocytes; monocytic reactivity was determined by TNF-production and expression of signalling lymphocytic activation molecule (SLAM). RESULTS: We observed that EAE-exacerbation upon depletion of un-activated B-cells closely correlated with an enhanced production of pro-inflammatory TNF by CD11b+ APC. Paralleling this pre-clinical finding, anti-CD20 treatment of human neuroimmunological disorders increased the relative frequency of monocytes and accentuated pro-inflammatory monocyte function; when reactivated ex vivo, a higher frequency of monocytes from B-cell depleted patients produced TNF and expressed the activation marker SLAM. CONCLUSIONS: These data suggest that in neuroimmunological disorders, pro-inflammatory APC activity is controlled by a subset of B-cells which is eliminated concomitantly upon anti-CD20 treatment. While this observation does not conflict with the general concept of B-cell depletion in human autoimmunity, it implies that its safety and effectiveness may further advance by selectively targeting pathogenic B-cell function.