Monoclonal anti-CD20 antibodies: Mechanisms of action and monitoring of biological effects

Pathophysiology of the Different Clinical Phenotypes of Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common form of autoimmune polyneuropathy. It is a chronic disease and may be monophasic, progressive or recurrent with exacerbations and incomplete remissions, causing accumulating disability. In recent years, there has been rapid progress in understanding the background of CIDP, which allowed us to distinguish specific phenotypes of this disease. This in turn allowed us to better understand the mechanism of response or non-response to various forms of therapy. On the basis of a review of the relevant literature, the authors present the current state of knowledge concerning the pathophysiology of the different clinical phenotypes of CIDP as well as ongoing research in this field, with reference to key points of immune-mediated processes involved in the background of CIDP.

Development of a novel reporter gene assay to evaluate antibody-dependent cellular phagocytosis for anti-CD20 therapeutic antibodies

More than 100 monoclonal antibodies (mAbs) have been approved by FDA. The mechanism of action (MoA) involves in neutralization of a specific target via the Fab region and Fc effector functions through Fc region, while the latter include complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). ADCP has been recognized one of the most important MoAs, especially for anti-cancer mAbs in recent years. However, traditional bioassays measuring ADCP always introduced primary macrophages and flow cytometry, which are difficult to handle and highly variable. In this study, we engineered a monoclonal Jurkat/NFAT/CD32a-FcεRIγ effector cell line that stably expresses CD32a-FcεRIγ chimeric receptor and NFAT-controlled luciferase. The corresponding mAb could bind with the membrane antigens on the target cells with its Fab fragment and CD32a-FcεRIγ on the effector cells with its Fc fragment, leading to the crosslinking of CD32a-FcεRIγ and the resultant expression of subsequent NFAT-controlled luciferase, which represents the bioactivity of ADCP based on the MoA of the mAb. With rituximab as the model mAb, Raji cells as the target cells, and Jurkat/NFAT/CD32a-FcεRIγ cells as the effector cells, we adopted the strategy of Design of Experiment (DoE) to optimize the bioassay. Then we fully validated the established bioassay according to ICH-Q2(R1), which proved the good assay performance characteristics of the bioassay, including specificity, accuracy, precision, linearity, stability and robustness. This RGA can be applied to evaluate the -ADCP bioactivity for anti-CD20 mAbs in lot release, stability testing as well as biosimilar comparability. The engineered cells may also potentially be used to evaluate the ADCP bioactivity of mAbs with other targets.

Solutions to Avoid False Positives for Rituximab in Pre-Transplant Crossmatches

Rituximab (anti-CD20) is commonly used as immunotherapy against B cells, in the context of pre-transplant crossmatches, where the presence of rituximab in the tested sera with donor cells can alter their results both by flow cytometry (FCXM) as complement-dependent cytotoxicity (CDCXM) giving rise to false positives. In the present study, we tested the use of an anti-rituximab monoclonal antibody (10C5, Abnova) as a method to avoid false positives in FCXM and CDCXM. We used the serum from ten patients who received therapy with rituximab, and the cells were incubated with sera treated or untreated with the 10C5 clone. In previous studies, attempts have been made to control these false positives through the use of pronase, although in these cases the alteration of Human Leukocyte Antigen (HLA) molecules has been found to be a limitation. As an alternative, we performed an assay to exclude false positives by a pre-incubation with anti-rituximab antibody (10C5) in 1:5 proportion avoiding the misinterpretation of crossmatches, particularly in patients with specific donor antibodies (DSA) without affecting the HLA molecules.

Bespoke Pretargeted Nanoradioimmunotherapy for the Treatment of Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) is one of the most common types of hematologic malignancies. Pretargeted radioimmunotherapy (PRIT), the sequential administration of a bispecific antibody-based primary tumor-targeting component followed by a radionucleotide-labeled treatment effector, has been developed to improve the treatment efficacy and to reduce the side effects of conventional RIT. Despite the preclinical success of PRIT, clinical trials revealed that the immunogenicity of the bispecific antibody as well as the presence of competing endogenous effector molecules often compromised the treatment. One strategy to improve PRIT is to utilize bio-orthogonal ligation reactions to minimize immunogenicity and improve targeting. Herein, we report a translatable pretargeted nanoradioimmunotherapy strategy for the treatment of NHL. This pretargeting system is composed of a dibenzylcyclooctyne (DBCO)-functionalized anti-CD20 antibody (α-CD20) tumor-targeting component and an azide- and yttrium-90-(90Y) dual-functionalized dendrimer. The physicochemical properties of both pretargeting components have been extensively studied. We demonstrated that an optimized dual-functionalized dendrimer can undergo rapid strain-promoted azide-alkyne cycloaddition with the DBCO-functionalized α-CD20 at the physiological conditions. The treatment effector in our pretargeting system can not only selectively deliver radionucleotides to the target tumor cells but also increase the complement-dependent cytotoxicity of α-CD20 and thus enhance the antitumor effects, as justified by comprehensive in vitro and in vivo studies in mouse NHL xenograft and disseminated models.

Kinetic analysis of changes in T- and B-lymphocytes after anti-CD20 treatment in renal pathology

INTRODUCTION

The main objective of this study is to describe qualitatively and quantitatively the different immune lymphocyte phenotypes of patients with renal disease after treatment with anti-CD20.

MATERIAL AND METHODS

Two cohorts of transplanted and autoimmune kidney patients were compared: (1) Those who began treatment with Rituximab, matched (for sex, age and general clinical parameters) with (2) Non-treated control kidney patients. Different analyses were performed: (A) B-lymphocyte subpopulations; (B) T-cell subpopulations; (C) serum levels of BAFF, APRIL, Rituximab and anti-Rituximab; (D) rs396991 polymorphism of CD16a and at different time points for each type of analysis: (i) at baseline, (ii) day 15, (iii) at three and (iv) six months post-antiCD20.

RESULTS

(A) A depletion of all B cell subsets analysed was observed preferentially decreasing the CD40⁺memory B-cells, switched memory cells and plasmablasts. (B) A significant decreased percentage of CD4⁺T-lymphocytes was observed. A significant decrease of the percentage of memory T-cells and an increase in naïve T-cells was also observed. (C) A significant increase for APRIL was observed, as well as a positive correlation between the APRIL levels, and the differential of B-cells. (D) The presence of CD16a Valine-variant induced greater changes in the variations of total T-cell and T-naïve subpopulations.

CONCLUSION

Our results highlight that the treatment of renal disease with Rituximab affects T-cells, particularly naïve/memory balance, while APRIL could be also a secondary marker of this treatment. The sequential analysis of phenotypic alterations of B- and T-cells could help patient management, although further studies to identify periods of remission or clinical relapse are warranted.

Challenges and opportunities for monoclonal antibody therapy in veterinary oncology

Monoclonal antibodies (mAbs) have come to dominate the biologics market in human cancer therapy. Nevertheless, in veterinary medicine, very few clinical trials have been initiated using this form of therapy. Some of the advantages of mAb therapeutics over conventional drugs are high specificity, precise mode of action and long half-life, which favour infrequent dosing of the antibody. Further advancement in the field of biomedical sciences has led to the production of different forms of antibodies, such as single chain antibody fragment, Fab, bi-specific antibodies and drug conjugates for use in diagnostic and therapeutic purposes. This review describes the potential for mAbs in veterinary oncology in supporting both diagnosis and therapy of cancer. The technical and financial hurdles to facilitate clinical acceptance of mAbs are explored and insights into novel technologies and targets that could support more rapid clinical development are offered.

Overview of pathophysiology and treatment of human lupus nephritis

PURPOSE OF REVIEW

Despite recent developments and treatment successes, the outcome, and prognosis of patients with lupus nephritis (LuN) have not greatly changed since the 1980s. This review covers the application of new concepts to the understanding of renal inflammation and the study of new pharmacologic agents to improve patient outcomes.

RECENT FINDINGS

Studies have shown that the presence of anti-vimentin antibodies and T follicular helper cells in patient biopsies is associated with more severe interstitial inflammation, which has been tied to faster disease progression and onset of end-stage renal disease. Additionally, data regarding the role of serum IgE antidouble-stranded DNA antibodies in LuN by means of mediating IFN1 production by plasmacytoid dendritic cells are highlighted. Finally, a thorough review of completed and currently open clinical trials of therapeutic agents is provided.

SUMMARY

Current management of LuN is guided almost exclusively by glomerular involvement. Based on the data provided in this review, we argue that renal tubulointerstitial inflammation is no less important and represents an overlooked feature in the current clinical approach to patients. Tubulointerstitial inflammation is driven by both adaptive and innate immune mechanisms that are still poorly understood. Studying these pathogenic processes promises to reveal new therapeutic opportunities for those LuN patients with the worst prognosis.

VIDEO ABSTRACT

Alternate video abstract introduction (see Video, Supplemental Digital Content 1, with introduction by two of the authors - VL and KT). Abstract Video: http://links.lww.com/COR/A35.

Rituximab in autoimmune thrombotic thrombocytopenic purpura: A success story

Despite a significant improvement of thrombotic thrombocytopenic purpura (TTP) prognosis since the use of plasma exchange, morbidity and mortality remained significant because of poor response to standard treatment or exacerbations and relapses. Rituximab, a chimeric monoclonal antibody directed against the B-lymphocyte CD20 antigen, has shown a particular interest in this indication. Recent studies also reported strong evidence for its efficiency in the prevention of relapses. This review addresses these recent progresses and still opened questions in this topic: should rituximab be proposed in all patients at the acute phase? Should all patients benefit from a preemptive treatment? Is the infectious risk acceptable in this context?

Rituximab for the treatment of IgG4-related orbital disease: experience from five cases

PURPOSE

To review the clinical efficacy and safety of rituximab for treatment of IgG4-related orbital disease (IgG4-ROD).

DESIGN

Retrospective multicentre interventional case series.

METHODS

Chart review for five cases of biopsy-confirmed IgG4-ROD (IgG4+>10/HPF, ratio of IgG4+/IgG+>40%) treated with rituximab. Information retrieved included the dosing schedule, adverse events and the magnitude, temporality, and duration of the clinical response.

RESULTS

All cases of IgG4-ROD were either steroid dependent or steroid resistant. Rituximab doses for induction therapy included two doses of 1000 mg at 2-weekly intervals, and four doses at 375 mg/m(2) at weekly intervals. Two months after starting rituximab, three cases achieved complete clinical resolution and two cases achieved partial clinical resolution. Complete radiological resolution occurred in one case, and partial radiological resolution in three cases. Three cases received rituximab maintenance therapy and one case was commenced on mycophenolate. No relapse occurred during a mean follow-up of 33 months (range: 7-65 months). One disease relapse occurred when the dosing interval of rituximab maintenance therapy was extended to 6-monthly intervals; remission was swiftly achieved with rituximab reinduction therapy. The only adverse effects reported were one episode of fatigue lasting 1 week and two episodes of orbital discomfort.

CONCLUSION

Rituximab may be an effective treatment option for IgG4-ROD that is steroid dependent or steroid intolerant. Rituximab therapy resulted in swift clinical and radiological improvement, many months free of relapse, and few side effects.

Mass-Production and Characterization of Anti-CD20 Monoclonal Antibody in Peritoneum of Balb/c Mice

PURPOSE

Monoclonal antibodies are important tools are used in basic research as well as, in diagnosis, imaging and treatment of immunodeficiency diseases, infections and cancers. The purpose of this study was to produce large scale of monoclonal antibody against CD20 in order to diagnostic application in leukemia and lymphomas disorders.

METHODS

Hybridoma cells that produce monoclonal antibody against human CD20 were administered into the peritoneum of the Balb/c mice which have previously been primed with 0.5 ml Pristane. After twelve days, approximately 7 ml ascetic fluid was harvested from the peritoneum of each mouse. Evaluation of mAb titration was assessed by ELISA method. In the present study, we describe a protocol for large scale production of MAbs.

RESULTS

We prepared monoclonal antibodies (mAbs) with high specificity and sensitivity against human CD20 by hybridoma method and characterized them by ELISA. The subclass of antibody was IgG2a and its light chain was kappa. Ascetic fluid was purified by Protein-A Sepharose affinity chromatography and the purified monoclonal antibody was conjugated with FITC and Immunofluorescence was done for confirming the specific binding.

CONCLUSION

The conjugated monoclonal antibody could have application in diagnosis B-cell lymphomas, hairy cell leukemia, B-cell chronic lymphocytic leukemia, and melanoma cancer stem cells.

Immunoglobulin G4-related sclerosing disease of the paranasal sinus

BACKGROUND

Immunoglobulin G4 (IgG4)-related sclerosing disease is a systemic disease characterized by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs. We present a case of a 69-year-old man with maxillary sinus IgG4 sclerosing disease, with orbital invasion treated with rituximab and dexamethasone pulse therapy. Surgery was used as well to debulk the disease and to obtain tissue for diagnosis.

METHODS

A PubMed search using the key phrase "IgG4-related Sclerosing Disease" was performed. There were 304 different articles regarding the disease for a multitude of different organ sites. Of the 304 articles, there were 3 articles that reported this disease in the paranasal sinuses.

CONCLUSIONS

IgG4-related sclerosing disease is a rare entity in the head and neck. There are documented reports of steroid therapy for this disease, but the patient presented here demonstrated clinical progression of disease with steroids alone. The use of combination therapy of surgery, dexamethasone, and rituximab provided clinical improvement and stable disease determined by radiographic means.

Pharmacogenetics: implications for therapy in rheumatic diseases

DMARDs not only improve the joint pain and swelling associated with rheumatoid arthritis (RA), but also slow down the joint damage associated with the disease. The efficacy of biologic therapies, introduced in the past decade for the treatment of RA, has been unequivocally established. Similarly, in addition to traditional drugs such as hydroxychloroquine, new biologic agents such as rituximab have been introduced for systemic lupus erythematosus in recent years. However, considerable variability occurs in the responses of patients to these therapies. Pharmacogenetics, the study of variations in genes encoding drug transporters, drug-metabolizing enzymes and drug targets, and their translation to differential responses to drugs, is a rapidly progressing field in rheumatology. Pharmacogenetic applications, particularly to the old vanguard DMARD, methotrexate, and the newer, more expensive biologic agents, might make personalized therapy in rheumatic diseases possible. The pharmacogenetics of commonly used DMARDs and of biologic therapies are described in this Review.