Hepatitis B reactivation is a rare event among patients with resolved infection undergoing anti-CD20 antibodies in monotherapy without antiviral prophylaxis: results from the HEBEM study.

INTRODUCTION: Prospective data on the risk of hepatitis B reactivation (HBVr) among patients with resolved HBV infection undergoing anti-CD20 antibodies monotherapy is scarce. We aimed to assess the risk of HBVr in patients with resolved HBV infection treated with rituximab or ocrelizumab in monotherapy for multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD) without antiviral prophylaxis. METHODS: HEBEM is a prospective study that included all consecutive adults HBsAg-negative/anti-HBc-positive who initiated anti-CD20 antibodies for MS or NMOSD at Cemcat. Inclusion criteria encompassed undetectable HBV-DNA, absence of other immunosuppressants or antiviral therapy. Every 6 months HBsAg, ALT and HBV-DNA were performed to rule out HBVr (defined by 2-log increase in HBV-DNA or seroconversion to HBsAg+). RESULTS: From August/2019 to August/2022, 540 subjects initiated anti-CD20 antibodies, 28 (5.2%) were anti-HBc-positive and were included. Twenty-two received rituximab and 6 ocrelizumab. The majority (89.3%) had previously received ≥ 1 immunomodulatory drug, with corticosteroids (82.1%) and interferon (42.9%) as the most common. At inclusion, all presented normal transaminases and undetectable HBV-DNA. Median anti-HBs levels were 105.5 mIU/mL (IQR 0-609). Median follow-up was 3.1 years (2.1-4.0). Median number of cycles of anti-CD20 antibodies was 6 (3-7), with a cumulative dose of 8.5 g (5.8-11.2) of rituximab and 3 g (1.8-3.8) of ocrelizumab. Neither cases of HBVr nor changes in anti-HBs titers were observed per 83.6 patient-years treated with monotherapy with anti-CD20 antibodies. CONCLUSIONS: In this cohort of patients with MS or NMOSD and resolved HBV infection, anti-CD20 monotherapy was not associated with detectable risk of HBV reactivation despite the lack of antiviral prophylaxis.

Indirect Treatment Comparisons of Mosunetuzumab With Third- and Later-Line Treatments for Relapsed/Refractory Follicular Lymphoma.

BACKGROUND: No established standard of care exists for relapsed/refractory (RR) follicular lymphoma (FL) after ≥2 prior therapies. We conducted indirect treatment comparisons (ITCs) to compare the efficacy and tolerability of mosunetuzumab with those of available treatments used in this setting. METHODS: A systematic literature review (SLR) and subsequent feasibility assessments were conducted to identify the most suitable comparator studies in terms of design, available endpoints and populations. Imbalances in patient characteristics between NCT02500407 and studies featuring aggregate or patient-level data availability were accounted for using matching-adjusted indirect comparison (MAIC) and propensity score-based methodologies, respectively. RESULTS: ZUMA-5, ELARA, DELTA, DYNAMO, UNITY-NHL, AUGMENT and NCT01897571 passed the MAIC feasibility assessment. Patient-level data were available from GADOLIN, CONTRALTO and NCT02257567. MAIC results generally favored mosunetuzumab over tazemetostat in EHZ2wild-type patients for all outcomes and over PI3K inhibitors for complete response (CR), objective response rate (ORR), discontinuations due to adverse events and progression-free survival (PFS) with umbralisib. MAICs favored CART therapies for PFS and, to a lesser extent, ORR and CR. Comparisons with anti-CD20 antibody-based regimens yielded mixed results. CONCLUSIONS: ITCs suggest that mosunetuzumab may lead to superior outcomes over tazemetostat (in EHZ2wild-type patients) and PI3K inhibitors and may be a promising alternative to re-challenging with a different anti-CD20 regimen in patients who relapse after ≥2 prior anti-CD20 lines. Although preliminary results somewhat favored CART therapies, limitations and uncertainties remain because of intrinsic differences in study design. Mosunetuzumab could thus be a promising treatment option for patients with RR FL after ≥2 prior therapies.

Anti-CD20 Antibody and Calcineurin Inhibitor Combination Therapy Effectively Suppresses Antibody-Mediated Rejection in Murine Orthotopic Lung Transplantation.

Antibody-mediated rejection (AMR) is a risk factor for chronic lung allograft dysfunction, which impedes long-term survival after lung transplantation. There are no reports evaluating the efficacy of the single use of anti-CD20 antibodies (aCD20s) in addition to calcineurin inhibitors in preventing AMR. Thus, this study aimed to evaluate the efficacy of aCD20 treatment in a murine orthotopic lung transplantation model. Murine left lung transplantation was performed using a major alloantigen strain mismatch model (BALBc (H-2d) → C57BL/6 (BL/6) (H-2b)). There were four groups: isograft (BL/6→BL/6) (Iso control), no-medication (Allo control), cyclosporine A (CyA) treated, and CyA plus murine aCD20 (CyA+aCD20) treated groups. Severe neutrophil capillaritis, arteritis, and positive lung C4d staining were observed in the allograft model and CyA-only-treated groups. These findings were significantly improved in the CyA+aCD20 group compared with those in the Allo control and CyA groups. The B cell population in the spleen, lymph node, and graft lung as well as the levels of serum donor-specific IgM and interferon γ were significantly lower in the CyA+aCD20 group than in the CyA group. Calcineurin inhibitor-mediated immunosuppression combined with aCD20 therapy effectively suppressed AMR in lung transplantation by reducing donor-specific antibodies and complement activation.

Risk factors and outcomes of COVID-19 in adult patients with hematological malignancies: A single-center study showing lower than expected rates of hospitalization and mortality.

BACKGROUND: Studies addressing coronavirus disease 2019 (COVID-19) in patients with hematological malignancies have reported mortality rates of up to 40%; however, included predominantly hospitalized patients. METHODS: During the first year of the pandemic, we followed adult patients with hematological malignancies treated at a tertiary center in Jerusalem, Israel, who contracted COVID-19, with the aim of studying risk factors for adverse COVID-19-related outcomes. We used remote communication to track patients managed at home-isolation, and patient questioning to assess the source of COVID-19 infection, community versus nosocomial. RESULTS: Our series included 183 patients, median age was 62.5 years, 72% had at least one comorbidity and 39% were receiving active antineoplastic treatment. Hospitalization, critical COVID-19, and mortality rates were 32%, 12.6%, and 9.8%, respectively, remarkably lower than previously reported. Age, multiple comorbidities, and active antineoplastic treatment were significantly associated with hospitalization due to COVID-19. Treatment with monoclonal antibodies was strongly associated with both hospitalization and critical COVID-19. In older (≥60) patients not receiving active antineoplastic treatment, mortality, and severe COVID-19 rates were comparable to those of the general Israeli population. We did not detect patients that contracted COVID-19 within the Hematology Division. CONCLUSION: These findings are relevant for the future management of patients with hematological malignancies in COVID-19-affected regions.

Anti-CD20 antibodies and bendamustine attenuate humoral immunity to COVID-19 vaccination in patients with B-cell non-Hodgkin lymphoma.

Serologic responses of COVID-19 vaccine are impaired in patients with B-cell lymphoma, especially those who had recently been treated with anti-CD20 monoclonal antibodies. However, it is still unclear whether those patients develop an immune response following vaccination. We investigated the efficacy of vaccination against SARS-CoV-2 in 171 patients with B-cell non-Hodgkin lymphoma (B-NHL) who received two doses of an mRNA-based COVID-19 vaccine and we compared the efficacy of vaccination to that in 166 healthy controls. Antibody titers were measured 3 months after administration of the second vaccine dose. Patients with B-NHL showed a significantly lower seroconversion rate and a lower median antibody titer than those in healthy controls. The antibody titers showed correlations with the period from the last anti-CD20 antibody treatment to vaccination, the period from the last bendamustine treatment to vaccination and serum IgM level. The serologic response rates and median antibody titers were significantly different between diffuse large B-cell lymphoma (DLBCL) patients in whom anti-CD20 antibody treatment was completed within 9 months before vaccination and follicular lymphoma (FL) patients in whom anti-CD20 antibody treatment was completed within 15 months before vaccination. Moreover, the serologic response rates and median antibody titers were significantly different among FL patients in whom bendamustine treatment was completed within 33 months before vaccination. We demonstrated that B-NHL patients who were recently treated with anti-CD20 antibodies and bendamustine had a diminished humoral response to COVID-19 vaccination. UMIN 000,045,267.

Real world safety of CT-P10 (anti-CD 20 monoclonal antibodies biosimilar) in rheumatic and autoimmune diseases.

BACKGROUND: Rituximab (RTX), anti-CD 20 monoclonal antibodies, has been approved for many rheumatic and autoimmune diseases, the use of RTX is still limited due to financial constrain. Biosimilar RTX may increase access by offering patients a more affordable option, lead to improved patient outcomes. However, real-world data related to its immediate and short-term safety is scarce. This study aimed to evaluate the real-world immediate and short-term safety profiles of CT-P10, a biosimilar of Rituximab, in patients with rheumatic and autoimmune diseases. METHODS: This prospective study included patients diagnosed with rheumatic or autoimmune diseases, aged ≥ 18 years, who were treated with biosimilar RTX at Siriraj or Ramathibodi Hospital during February 2019 to May 2019. Patients were followed up through 6 months after the infusions. RESULTS: Of the 74 patients, with 124 infusions, 84% were females with mean age (SD) of 49.4 (15.7) years. The most common rheumatic and autoimmune disease included in this study was systemic lupus erythematosus (26%). All immediate adverse events (AEs) (15 out of 124 infusions) were mild requiring only symptomatic and supportive treatment. Short-term AEs included infection (N = 35), hematologic abnormalities (N = 33), chylous ascites (N = 1), and others (N = 10). Two deaths were related to serious bacterial and viral infection. Hematologic AEs comprised anemia (N = 5), neutropenia (N = 10), lymphopenia (N = 15), and thrombocytopenia (N = 3). CONCLUSION: In this real-world study, biosimilar RTX (CT-P10) has favorable immediate and short-term safety profiles. However, further studies with large sample size and long-term follow-up in real-world practice are still required to confirm the result.

The value of FDG PET/CT imaging in outcome prediction and response assessment of lymphoma patients treated with immunotherapy: a meta-analysis and systematic review.

PURPOSE: Treatment strategies of lymphoid malignancies have been revolutionized by immunotherapy. Because of the inherent property of Hodgkin lymphoma and some subtypes of non-Hodgkin lymphoma as a highly FDG-avid tumor, functional 18F-FDG PET/CT imaging is already embedded in their routine care. Nevertheless, the question is whether it is still valuable in the context of these tumors being treated with immunotherapy. Herein, we will review the value of 18F-FDG PET/CT imaging lymphoid tumors treated with immunotherapy regimens. METHODS: A comprehensive literature search of the PubMed database was conducted on the value of the 18F-FDG PET/CT for immunotherapy response monitoring of patients with malignant lymphoma. The articles were considered eligible if they met all of the following inclusion criteria: (a) clinical studies on patients with different types of malignant lymphoma, (b) treatment with anti-CD20 antibodies, immune checkpoint inhibitors or immune cell therapies, (c) and incorporated PET/CT with 18F-FDG as the PET tracer. RESULTS: From the initial 1488 papers identified, 91 were ultimately included in our study. In anti-CD20 therapy, the highest pooled hazard ratios (HRs) of baseline, early, and late response monitoring parameters for progression-free survival (PFS) belong to metabolic tumor volume (MTV) (3.19 (95%CI: 2.36-4.30)), maximum standardized uptake value (SUVmax) (3.25 (95%CI: 2.08-5.08)), and Deauville score (DS) (3.73 (95%CI: 2.50-5.56)), respectively. These measurements for overall survival (OS) were MTV (4.39 (95%CI: 2.71-7.08)), DS (3.23 (95%CI: 1.87-5.58)), and DS (3.64 (95%CI: 1.40-9.43)), respectively. Early and late 18F-FDG PET/CT response assessment in immune checkpoint inhibitors (ICI) and immune cell therapy might be an effective tool for prediction of clinical outcome. CONCLUSION: For anti-CD20 therapy of lymphoma, the MTV as a baseline 18F-FDG PET/CT-derived parameter has the highest HRs for PFS and OS. The DS as visual criteria in early and late response assessment has higher HRs for PFS and OS compared to the international harmonization project (IHP) visual criteria in anti-CD20 therapy. Early changes in 18F-FDG PET parameters may be predictive of response to ICIs and cell therapy in lymphoma patients.

Remdesivir in Coronavirus Disease 2019 patients treated with anti-CD20 monoclonal antibodies: a case series.

PURPOSE: COVID-19 patients on anti-CD20 treatment can suffer a delayed viral clearance and worse clinical outcome. We aim to present our experience with remdesivir treatment in anti-CD20-treated patients with prolonged symptoms, a patient population for which no data from randomized controlled trials are available. METHODS: From the beginning of the pandemic until February 2021, we included all consecutive patients from our healthcare network on anti-CD20 treatment with prolonged COVID-19 symptoms, who received remdesivir. Patient informed consent was gathered and patients' charts were reviewed to collect baseline data, COVID-19 history including time of symptom onset, diagnosis, data on treatment and disease course. Patients or their next of kin were contacted in March 2022 to assess long-term outcomes. RESULTS: We included 11 patients, who received remdesivir at a median of 33 days after diagnosis. Eight patients showed clinical improvement along with reductions in viral loads, one patient with relapsing infection recovered after administration of convalescent plasma, and two patients died. No clinical relapses were reported (median follow-up 13 months), while follow-up PCRs were not performed. One patient died of underlying malignancy 8 months after recovery from COVID-19. CONCLUSIONS: We observed a benefit of antiviral therapy in a majority of COVID-19 patients on anti-CD20 treatment, without any clinical relapses in the 1-year follow-up. Although these data suggest that remdesivir might be a promising management option in patients with delayed viral clearance, the lack of a control group is an important limitation of the study design. TRIAL REGISTRATION: Ethikkommission Ostschweiz, Scheibenackerstrasse 4, CH-9000 St. Gallen approved this case series. Project-ID 2021-00349 EKOS 21/027.

New and Old Anti-CD20 Monoclonal Antibodies for Nephrotic Syndrome. Where We Are?

Nephrotic proteinuria is the hallmark of several glomerulonephritis determined by different pathogenetic mechanisms, including autoimmune, degenerative and inflammatory. Some conditions such as Minimal Change Nephropathy (MCN) and Focal Segmental Glomerulosclerosis (FSGS) are of uncertain pathogenesis. Chimeric anti-CD20 monoclonal antibodies have been used with success in a part of proteinuric conditions while some are resistant. New human and humanized monoclonal anti-CD 20 antibodies offer some advantages based on stronger effects on CD20 cell subtypes and have been already administered in hematology and oncology areas as substitutes of chimeric molecules. Here, we revised the literature on the use of human and humanized anti-CD 20 monoclonal antibodies in different proteinuric conditions, resulting effective in those conditions resistant to rituximab. Literature on the use of human anti-CD 20 monoclonal antibodies in different proteinuric diseases is mainly limited to ofatumumab, with several protocols and doses. Studies already performed with ofatumumab given in standard doses of 1,500 mg 1.73m2 suggest no superiority compared to rituximab in children and young adults with steroid dependent nephrotic syndrome. Ofatumumab given in very high doses (300 mg/1.73m2 followed by five infusion 2,000 mg/1.73 m2) seems more effective in patients who are not responsive to common therapies. The question of dose remains unresolved and the literature is not concordant on positive effects of high dose ofatumumab in patients with FSGS prior and after renal transplantation. Obinutuzumab may offer some advantages. In the unique study performed in patients with multidrug dependent nephrotic syndrome reporting positive effects, obinutuzumab was associated with the anti-CD38 monoclonal antibody daratumumab proposing the unexplored frontier of combined therapies. Obinutuzumab represent an evolution also in the treatment of autoimmune glomerulonephritis, such as membranous nephrotahy and lupus nephritis. Results of randomized trials, now in progress, are awaited to add new possibilities in those cases that are resistant to other drugs. The aim of the present review is to open a discussion among nephrologists, with the hope to achieve shared approaches in terms of type of antibodies and doses in the different proteinuric renal conditions.

Pemphigus Vulgaris: Present and Future Therapeutic Strategies.

Pemphigus vulgaris (PV) belongs to the group of autoimmune blistering diseases. PV can affect not only mucous membranes, but also the skin and it is characterized by serum IgG autoantibodies against desmoglein 1 and 3, two major components of desmosomes. The introduction of glucocorticoids improved dramatically the prognosis of patients affected by PV. However, long-term use of high dose corticosteroids and adjuvant steroid-sparing immunosuppressants can lead to several adverse events. Rituximab, a chimeric anti-CD20 monoclonal antibody, has been recently approved as in-label therapy for PV, leading to an improvement of the prognosis and higher remission rate. Furthermore, other anti B-cell therapies and several anti-CD20 biosimilars have been introduced in the clinical practice. We focused on present and future therapeutic approaches in PV.

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.

Atypical COVID-19 dynamics in a patient with mantle cell lymphoma exposed to rituximab.

Patients with non-hodgkin lymphomas (NHL) represent a population of special interest during the current Coronavirus disease-19 (COVID-19) pandemics. NHLs are associated with disease- and treatment-related immunodeficiencies which may generate unusual COVID-19 dynamics and pose unique management challenges. We report the unusual clinical course of COVID-19 in a patient with mantle cell lymphoma (MCL) exposed to nine doses of Rituximab shortly before infection with severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). He had a prolonged asymptomatic phase, with negative molecular and antibody testing for SARS-CoV-2, followed by a rapidly progressive evolution to severe COVID-19. Despite detection of viral RNA overlapped with first symptoms occurrence, anti-SARS-CoV-2 antibodies displayed an asynchronous pattern, with IgG first appearing 2 days after RNA positivity and IgM never being detected throughout the entire clinical course. While disease-associated immune derangements and/or previous treatments involving anti-CD20 antibodies might have contributed to COVID-19 dynamics in our patient, data suggests that antibody testings, without concurrent molecular assessment for SARS-CoV-2, may turn inadequate for monitoring of MCL patients, and in general NHL patients heavily exposed to anti-CD20 antibodies, during the current pandemics. We suggest that repeated molecular testing of nasopharyngeal swab should be implemented in these subjects despite a negative serology and absence of symptoms of SARS-CoV-2 infection. For the same reasons, a customized strategy needs to be developed for patients exposed to anti-CD20 antibodies, based on different features and mechanism of action of available SARS-CoV-2 vaccines and novel vaccinomics developments.

Profiling of donor-specific immune effector signatures in response to rituximab in a human whole blood loop assay using blood from CLL patients.

Rituximab is widely used in the treatment of haematological malignancies, including chronic lymphocytic leukaemia (CLL), the most common leukaemia in adults. However, some patients, especially those with high tumour burden, develop cytokine release syndrome (CRS). It is likely that more patients will develop therapy-linked CRS in the future due to the implementation of other immunotherapies, such as CAR T-cell, for many malignancies. Current methods for CRS risk assessment are limited, hence there is a need to develop new methods. To better recapitulate an in vivo setting, we implemented a unique human whole blood "loop" system to study patient-specific immune responses to rituximab in blood derived from CLL patients. Upon rituximab infusion, both complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) profiles were evident in CLL patient blood, coincident with CLL cell depletion. Whereas B cell depletion is induced in healthy persons in the blood loop, only patients display B cell depletion coupled with CRS. With the exception of one donor who lacked NK cells, all other five patients displayed variable B cell depletion along with CRS profile. Additionally, inhibition of CDC or ADCC via either inhibitors or antibody Fc modification resulted in skewing of the immune killing mechanism consistent with published literature. Herein we have shown that the human whole blood loop model can be applied using blood from a specific indication to build a disease-specific CRS and immune activation profiling ex vivo system. Other therapeutic antibodies used for other indications may benefit from antibody characterization in a similar setting.

Anti-CD20-Mediated B Cell Depletion Is Associated With Bone Preservation in Lymphoma Patients and Bone Mass Increase in Mice.

Immunotherapy with anti-CD20-specific antibodies (rituximab), has become the standard of care for B cell lymphoproliferative disorders and many autoimmune diseases. In rheumatological patients the effect of rituximab on bone mass yielded conflicting results, while in lymphoma patients it has not yet been described. Here, we used cross-sectional X-ray imaging (CT/PET-CT) to serially assess bone density in patients with follicular lymphoma receiving rituximab maintenance therapy. Remarkably, this treatment prevented the decline in bone mass observed in the control group of patients who did not receive active maintenance therapy. In accordance with these data, anti-CD20-mediated B cell depletion in normal C57BL/6J female mice led to a significant increase in bone mass, as reflected by a 7.7% increase in bone mineral density (whole femur), and a ~5% increase in cortical as well as trabecular tissue mineral density. Administration of anti-CD20 antibodies resulted in a significant decrease in osteoclastogenic signals, including RANKL, which correlated with a reduction in osteoclastogenic potential of bone marrow cells derived from B-cell-depleted animals. Taken together, our data suggest that in addition to its anti-tumor activity, anti-CD20 treatment has a favorable effect on bone mass. Our murine studies indicate that B cell depletion has a direct effect on bone remodeling.

Anti-CD20 rituximab IgG1, IgG3, and IgG4 but not IgG2 subclass trigger Ca2+ mobilization and cytotoxicity in human NK cells.

NK cell-mediated Ab-dependent cellular cytotoxicity (ADCC) is increasingly recognized to play an important role in cancer immunotherapy, transplant rejection, and autoimmunity. However, several aspects of the molecular interactions of IgG subclasses with the Fc-gamma receptor IIIA (FcγRIIIA)/CD16a expressed on NK cells remain unknown. The aim of the current study was to further analyze the role of IgG subclasses and FCGR3A V158F single nucleotide polymorphism (SNP) on Ca2+ signaling and NK cell-mediated ADCC against Daudi target cells in vitro. NK cells were isolated from donors with different FCGR3A SNP. The affinity of rituximab IgG subclasses to CD20 expressed on Daudi cells showed similar dissociation constant as tested by flow cytometry. Induction of Ca2+ signaling, degranulation, intracellular cytokine production, and ADCC was demonstrated for IgG1 and IgG3, to a lesser degree also for IgG4, but not for IgG2. Compared to NK cells carrying the low-affinity (FF) variant for the FCGR3A V158F SNP, binding of IgG1 and IgG3 to NK cells carrying the high-affinity (VV) and VF SNP variants was two- to threefold higher. Variations of FCGR3A SNP among the eight tested donors (1 VV, 3FF, and 4VF) revealed no significant differences of Ca2+ signaling and degranulation; however, ADCC was somewhat weaker in donors with the low-affinity FF variation. In conclusion, this is the first study correlating Ca2+ signaling and NK cell-mediated ADCC triggered by the four IgG subclasses with the FCGR3A V158F SNP. Our findings indicate important differences in the interactions of IgG subclasses with FcγRIIIA/CD16a but no major impact of FCGR3A SNP and may therefore help to better correlate the functional properties of particular engineered therapeutic antibodies in vitro with individual differences of their clinical efficacy.

Antibody Therapy Maintenance in Follicular Lymphoma.

Because patients with follicular lymphoma (FL) usually experience repeated disease recurrences, maintenance treatment is an attractive option to prolong remission after induction therapy. Rituximab maintenance therapy has been shown in multiple randomized studies to significantly improve progression-free survival in FL with both low and high tumor burden after induction therapy, independently of patient and disease characteristics. Several questions regarding the use of antibody directed against CD20 (anti-CD20) maintenance remain open, including the optimal antibody administration schedule and duration, the risk/benefit ratio of maintenance in the context of previous bendamustine administration, and its cost-effectiveness.

Pemphigus: Current and Future Therapeutic Strategies.

Pemphigus encompasses a heterogeneous group of autoimmune blistering diseases, which affect both mucous membranes and the skin. The disease usually runs a chronic-relapsing course, with a potentially devastating impact on the patients' quality of life. Pemphigus pathogenesis is related to IgG autoantibodies targeting various adhesion molecules in the epidermis, including desmoglein (Dsg) 1 and 3, major components of desmosomes. The pathogenic relevance of such autoantibodies has been largely demonstrated experimentally. IgG autoantibody binding to Dsg results in loss of epidermal keratinocyte adhesion, a phenomenon referred to as acantholysis. This in turn causes intra-epidermal blistering and the clinical appearance of flaccid blisters and erosions at involved sites. Since the advent of glucocorticoids, the overall prognosis of pemphigus has largely improved. However, mortality persists elevated, since long-term use of high dose corticosteroids and adjuvant steroid-sparing immunosuppressants portend a high risk of serious adverse events, especially infections. Recently, rituximab, a chimeric anti CD20 monoclonal antibody which induces B-cell depletion, has been shown to improve patients' survival, as early rituximab use results in higher disease remission rates, long term clinical response and faster prednisone tapering compared to conventional immunosuppressive therapies, leading to its approval as a first line therapy in pemphigus. Other anti B-cell therapies targeting B-cell receptor or downstream molecules are currently tried in clinical studies. More intriguingly, a preliminary study in a preclinical mouse model of pemphigus has shown promise regarding future therapeutic application of Chimeric Autoantibody Receptor T-cells engineered using Dsg domains to selectively target autoreactive B-cells. Conversely, previous studies from our group have demonstrated that B-cell depletion in pemphigus resulted in secondary impairment of T-cell function; this may account for the observed long-term remission following B-cell recovery in rituximab treated patients. Likewise, our data support the critical role of Dsg-specific T-cell clones in orchestrating the inflammatory response and B-cell activation in pemphigus. Monitoring autoreactive T-cells in patients may indeed provide further information on the role of these cells, and would be the starting point for designating therapies aimed at restoring the lost immune tolerance against Dsg. The present review focuses on current advances, unmet challenges and future perspectives of pemphigus management.