A comprehensive analysis of treatment outcomes in patients with pemphigus vulgaris treated with rituximab

Comparison of the Clinical Efficacy of Rituximab Infusion and Dexamethasone-Cyclophosphamide Pulse Therapy and Their Effect on Serum Th1, Th2, and Th17 Cytokines in Pemphigus Vulgaris-A Prospective, Nonrandomized, Comparative Pilot Study

Background

Rituximab infusion and dexamethasone-cyclophosphamide pulse (DCP) are the two most popular regimens used in pemphigus vulgaris (PV) in India.

Objective

The present study compared the clinical efficacy of rituximab and DCP in Indian PV patients and their effects on serum Th1,2, and 17 cytokine levels.

Materials and Methods

A total of 37 patients received DCP (Group A, n = 22) or rituximab (Group B, rheumatoid arthritis protocol (n = 15)) as per patients' preference. They were monitored for clinical response, adverse events (AEs), changes in serum anti-desmoglein-1,3 antibody titers and Th1,2 and 17 cytokine levels at baseline and weeks 20 and 52.

Results

The proportion of patients attaining disease control, remission, and relapse in groups A and B were 82% and 93%; 73% and 93%; and 27% and 50%, respectively, after a median duration of 2 months each for disease control; 4 and 4.5 months for remission; and 5 and 7 months for relapse post remission. The musculoskeletal AEs were the highest in the two groups. Significant and comparable decreases in anti-dsg1 and 3 titers from baseline to weeks 20 and 52 were observed in both groups. Th1 and Th17 cytokine levels decreased, while Th2 cytokines increased post-treatment in both groups. However, no correlation was found between change in body surface area of involvement by PV and anti-dsg titers and cytokine levels before and after therapy in both groups.

Conclusion

Comparable clinical efficacy between DCP and rituximab was observed.

Combination therapy for management of pemphigus patients with unexpected therapeutic response to rituximab: A report of five cases

Key Clinical Message

The immunosuppressant agents should be considered earlier in the course of treatment with rituximab, possibly after the unfavorable response at first cycle of treatment, especially in male patients and those with high BMI.

Abstract

Rituximab (RTX) has recently been proposed as an alternative first-line therapy for pemphigus patients. However, there are some rare reports of worsening of pemphigus following RTX therapy in the literature. This study aimed to evaluate the efficacy and safety of using a combination treatment of mycophenolate mofetil or dapsone and methotrexate in case of nonresponse, exacerbation or development of allergic reactions following rituximab therapy in pemphigus patients. In this case series, archive files of pemphigus patient in a tertiary care hospital from 2016 to 2021 who were treated with rituximab were reviewed and those with failure in treatment process including nonresponsiveness, exacerbation or development of allergic reactions to rituximab were identified and assessed. The study includes five patients out of 1245 RTX-treated patients, who did not respond to RTX (one patient) or experienced an exacerbation of disease (two patients) or development of allergic reactions (two patients). Male patients with high BMI (BMI > 25) whose response to rituximab was not good at first cycle and happened to receive rituximab later in the course of disease, had highest number of relapses and benefited the most from this combination immunosuppressive treatment as an alternative for repeating rituximab cycles. The lower risk of relapse and a better chance of remission might indicate the efficacy of adjuvant immunosuppressant therapy in patients with no-response, exacerbation, or allergic reaction to rituximab. These therapeutic effects were better observed in patients who received lower doses of rituximab which could suggest that the immunosuppressant agents should be considered earlier in the course of the disease, possibly after the first failed trial of rituximab therapy.

Current biologics in treatment of pemphigus foliaceus: a systematic review

Background

Pemphigus foliaceus (PF) differs from pemphigus vulgaris (PV) in that it affects only the skin and mucous membranes are not involved. Pemphigus is commonly treated with systemic corticosteroids and immunosuppressive agents (ISAs). More recently, biologics have been used. The current literature on biologic therapy often combines treatment of PF with PV, hence it is often difficult for clinicians to isolate the treatment of PF from PV. The purpose of this review was to provide information regarding the use of current biological therapy, specifically in PF.

Materials and methods

A search of PubMed, Embase, and other databases was conducted using keywords pemphigus foliaceus (PF), rituximab (RTX), intravenous immunoglobulin (IVIg), and biologics. Forty-one studies were included in this review, which produced 105 patients with PF, treated with RTX, IVIg, or a combination of both. Eighty-five patients were treated with RTX, eight patients with IVIg, and 12 received both RTX and IVIg.

Results

Most patients in this review had PF that was nonresponsive to conventional immunosuppressive therapies (CIST), and had significant side effects from their use. RTX treatment resulted in complete remission (CR) in 63.2%, a relapse rate of 39.5%, an infection rate of 19.7%, and a mortality rate of 3.9%. Relapse was greater in the lymphoma (LP) protocol than the rheumatoid arthritis (RA) protocol (p<0.0001). IVIg led to CR in 62.5% of patients, with no relapses or infections. Patients receiving both biologics experienced better outcomes when RTX was first administered, then followed by IVIg. Follow-up durations for patients receiving RTX, IVIg, and both were 22.1, 24.8, and 35.7 months, respectively.

Discussion

In pemphigus foliaceus patients nonresponsive to conventional immunosuppressive therapy or in those with significant side effects from CIST, RTX and IVIg appear to be useful agents. Profile of clinical response, as well as relapse, infection, and mortality rates in PF patients treated with RTX were similar to those observed in PV patients. The data suggests that protocols specific for PF may produce better outcomes, less adverse effects, and improved quality of life.

B-cell targeted therapy of pemphigus

Pemphigus is an autoimmune disease that causes blistering and erosion of the skin and mucous membranes because of autoantibodies against desmoglein, which plays an important role in adhesion between epidermal keratinocytes. Treatment of pemphigus has long been centered on corticosteroids, and the guidelines for management of pemphigus have recommended high-dose systemic corticosteroids as the first-line treatment. While guideline-based treatment has been shown to be beneficial in patients with pemphigus, it has also become clear that this treatment is accompanied by significant burden and risk. The challenge for future pemphigus treatment is to maximize efficacy while minimizing risk during the course of the disease. In this regard, treatment targeting B cells is expected to become increasingly important as autoreactive B cells in pemphigus patients are thought to play a major role in the production of autoantibodies, which form the basis of the pathogenesis. The recent expansion of insurance coverage to rituximab, a monoclonal antibody against CD20, for refractory pemphigus in the USA, Europe, and Japan has opened up a new era of pemphigus treatment by enabling treatment strategies with drugs targeting B cells in patients. Here, we discuss the current status and future prospects of pemphigus treatment, focusing on rituximab and Bruton's tyrosine kinase inhibitors, which are expected to become essential drugs for pemphigus treatment in the future.

Desmoglein compensation hypothesis fidelity assessment in Pemphigus

The pemphigus group of autoimmune blistering diseases encompasses pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Lesion location in pemphigus has been elegantly postulated by the Desmoglein Compensation Hypothesis (DCH), which references the distribution of desmoglein (Dsg) proteins in the epidermis along with a patient’s autoantibody profile to describe three different lesion phenotypes: PF is characterized by subcorneal lesions in the presence of anti-Dsg1 antibodies only, while lesions in PV are suprabasilar and accompanied by anti-Dsg3 antibodies only in mucosal PV, or both anti-Dsg3 and anti-Dsg1 in the case of mucocutaneous PV. While the validity of this hypothesis has been supported by several studies and is prominently featured in textbooks of dermatology, a number of logical inconsistencies have been noted and exceptions have been published in several small-scale studies. We sought to comprehensively assess the extent to which patient clinical and autoantibody profiles contradict the DCH, and characterize these contradictions in a large sample size of 266 pemphigus patients. Remarkably, we find that roughly half of active PV and PF patients surveyed present with a combination of lesion morphology and anti-Dsg3/1 levels that contradict the DCH, including: patients with a cutaneous only PV presentation, mucocutaneous disease in the absence of either Dsg3, Dsg1, or both, and mucosal disease in the absence of Dsg3 or presence of Dsg1. We also find stark differences in fidelity to the DCH based on ethnicity and HLA-association, with the lowest proportion of adherence in previously understudied populations. These findings underscore the need to expand our understanding of pemphigus morphology beyond the DCH, in particular for populations that have not been a focus in previous investigation.

Pemphigoid of the pulmonary system (POPS): A review of a less recognized feature

This review of Pemphigoid of the Pulmonary System (POPS) is a comprehensive description of pulmonary involvement in patients with mucous membrane pemphigoid (MMP), which is an orphan autoimmune blistering disease. The objective of the review was to analyze clinical features of pulmonary involvement in MMP. This POPS review is a case series in which multiple search engines were utilized from inception to June 2022 for cases of MMP with biopsy and immunopathology proven tracheal and bronchial pemphigoid. Clinical profiles prior to pulmonary involvement, bronchoscopy findings, clinical course and therapy were recorded and cause of death was analyzed. Patients with documented MMP who developed tracheal, bronchial and pulmonary involvement were included in the POPS review. Histology and immunopathology documentation were essential diagnostic criteria. Comparison groups were not possible. Patients were treated with immunosuppressive therapy. Some required surgical interventions. Six of the 11 patients attained complete or partial remission on or off therapy. Five patients died from pulmonary complications. The POPS review had six females and five males. The mean age at onset was 20 years (range 4-76), while 80% of the patients were under 40 years. All had severe widespread MMP involving three to five mucosal tissues. 100% had oral, 82% had ocular and cutaneous involvement. Pulmonary involvement occurred at 24 mo (range 2-372) after the onset of MMP. Bronchoscopy revealed acute inflammation during active disease and scarring of the trachea and bronchi in the later stages. Systemic infections occurred in 45%, while pulmonary infection occurred in 36%. Mortality due to respiratory failure, at the median age of 20 years (range 18-76), occurred in 45% of the patients, and was considered disease related. In spite of the young age, while there are some similarities in the clinical profile and response to systemic therapy, there are definitive differences from other patients with MMP. Early diagnosis with appropriate management could produce better clinical outcomes and prevent mortality in this orphan disease. Consequently, there is a critical need for early identification and diagnosis of POPS.

Use of rituximab in the treatment of mucous membrane pemphigoid: An analytic review

Mucous Membrane Pemphigoid (MMP) is a potentially fatal mucocutaneous autoimmune blistering disease. Autoantibodies are produced against various components of the dermo-epidermal or mucosal-submucosal junction are referred to as basement membrane zone (BMZ). The hallmark is deposition of of Ig and C3 on the perilesional tissues and in some patients detection of anti-BMZ autoantibodies. A unique characteristic of MMP is that as the blisters or erosions heal, they leave irreversible scarring. This scarring results in serious and catastrophic sequelae that affect the quality of life. Conventional therapy consists of anti-inflammatory and immunosuppressive agents (ISA). In patients who fail conventional therapy or develop significant side effects to them, rituximab (RTX) has been used off label. In this review, the clinical outcomes of patients with MMP treated with RTX were studied. 124 patients were identified, 47.58% being male. 72 patients were treated by the Lymphoma Protocol and 51 by Rheumatoid Arthritis (RA) protocol. Follow up for the entire cohort was 36 months (range 0.5-72). On follow-up 64 patients (51.61%) achieved complete clinical remission (CR) off therapy, 25 patients (20.16%) were in CR on therapy, 5 patients (4.03%) were non-responders, and 9 patients (7.25%) were failures. 52 patients (41.93%) experienced a relapse, after 36 months follow-up. Duration between last RTX infusion and relapse was 10.5 months (range 1-30). Most patients with relapses were treated with additional RTX. A statistically significant better outcome was observed in patients treated with RTX as monotherapy compared to those who received RTX with ISA. Clinical outcomes in patients treated with Lymphoma protocol were better than RA protocol at a statistically significant level. Data on CD20+ B cell depletion and repopulation was limited. Interestingly relapses were seen in patients with CD20+ B cell depletion and after repopulation. In the final analysis, 89 patients (71.77%) were in complete remission. Data in this review indicated that RTX was a useful agent to treat MMP. While a randomized control trial may not be practically possible, better and disease specific protocols need to be developed. When publishing, authors should attempt to provide complete and detailed information. In doing so, they will benefit their colleagues and the patients with MMP they treat with RTX.

Comparison of rituximab and intravenous immunoglobulin in the treatment of autoimmune bullous diseases: Real-life data from a single centre

BACKGROUND/AIM

Rituximab (RTX) and intravenous human immunoglobulin (IVIG) have been shown to be effective in the treatment of autoimmune bullous diseases (ABD), mainly pemphigus vulgaris (PV). The present study aimed to assess the clinical response of patients with ABD, mainly PV to RTX, IVIG and combined regimen of both. Whether adding IVIG to RTX therapy affects the achievement of complete remission off therapy (CR off), reduces time to CR off, time to steroid cessation, and decreases relapse rate was also investigated.

METHODS

Data of 33 patients with ABD [PV (93.9%)], including clinical response to treatment, steroid cessation time, time to CR off and relapse, were recruited from medical charts.

RESULTS

CR off and relapse rate, mean time to CR off and relapse was 86.7% (n = 13) vs 60.0% (n = 6) and 53.3% (n = 8) vs 40% (n = 4), 12.77 ± 9.30 vs 11.25 ± 13.40 and 24.1 ± 16.7 vs 13.0 ± 3.6 months in RTX and combination group, respectively. Older age (P = .005), younger age at the time of diagnosis (P = .004), lesser disease duration to the initiation of RTX (P = .004), lesser BMI (P = .026) and female gender (P = .037) were associated factors with CR off.

CONCLUSION

Adding IVIG to RTX did not increase CR off rates; it also did not decrease time to CR off, time to steroid cessation, relapse rates and did not increase time to relapse. Patient and disease characteristics, including age, younger age at the time of diagnosis, lesser disease duration before RTX treatment, lesser BMI and female gender, are factors associated with CR off.

Comparison of Guidelines for Management of Pemphigus: a Review of Systemic Corticosteroids, Rituximab, and Other Immunosuppressive Therapies

Pemphigus is a severe autoimmune bullous dermatosis that affects the skin and/or mucosa, and it may be life-threatening without proper treatment. The guidelines and/or consensus statements for treatment vary widely between groups. We selected 6 guidelines and consensus statements established by different associations about the management of pemphigus vulgaris (PV) and/or pemphigus foliaceus (PF) to review, compare, and contrast the similarities and differences of these recommendations and provide optimal management suggestions to physicians. Corticosteroids remain a first-line therapy for pemphigus, but there are many differences in initial dose, tapering schedule, and management of relapse between different guidelines. Rituximab is a monoclonal antibody targeting CD20-positive B lymphocytes that is approved as a first-line therapy in moderate-to-severe pemphigus. Immunosuppressive agents, such as azathioprine (AZA) and mycophenolate mofetil (MMF), are also widely used as corticosteroid-sparing drugs, but the adjuvant applications and dosage regimens of different recommendations are not standardized. We attribute these differences to the clinical scoring adopted, the standards for disease severity evaluation, the publication year of each guideline, and local and regional healthcare differences.

Biologics in autoimmune bullous diseases: Current scenario

Autoimmune bullous diseases can be intraepidermal (pemphigus group of disorders) or subepidermal (pemphigoid group of disorders). The treatment of these disorders chiefly comprises corticosteroids and immunosuppressant adjuvants like azathioprine and mycophenolate mofetil. Autoantibodies are the main mediators of these diseases. Rituximab, a chimeric anti-CD20 monoclonal antibody targeting B-cells, has emerged as an excellent treatment option for refractory pemphigus vulgaris in the last decade. Since then, many new biologics have been proposed/explored for managing autoimmune bullous diseases. These hold potential for greater efficacy and lesser adverse effects than conventional immunosuppressants. In this review, we discuss the role of various biologics in the treatment of autoimmune bullous diseases, followed by a brief discussion on the drawbacks to their use and new developments in this area.

De-escalation of anti-CD20 monoclonal antibody (Rituximab) protocols in Pemphigus Vulgaris - a systematic review

Introduction: This review assesses current evidence supporting dose de-escalated rituximab therapy in pemphigus vulgaris, compared to standard protocols. Primary outcome measures were remission and relapse rates. Adverse effects, cumulative steroid dosages, and serological markers of disease activity were also reported.Areas covered: A literature search was performed to look for reports describing the use of de-escalated rituximab therapy in pemphigus vulgaris. Results from heterogenous studies showed a large variation in remission and relapse rates. Complete remission rates from de-escalated treatment ranged from 41.7 to 100.0%, while rates in the control groups ranged from 60.0 to 90.9%. Relapse rates varied from 8.0 to 81.3% in the de-escalated group and from 0.0 to 72.4% in the control group. Of the 165 patients included in this report, only two major adverse effects were reported.Expert Opinion: Overall, dose de-escalated rituximab protocols reported to date appear effective and safe. However, it is unclear if treatment effect parallels that of standard regimens in regard to disease control in the long term. A lower limit of effective dosing for rituximab in pemphigus vulgaris has not yet been reached or defined. The role for and timing of repeated cycles of low-dose rituximab therapy require further exploration.

Long-term experience with rituximab therapy for treatment-resistant moderate-to-severe pemphigus

BACKGROUND

Rituximab appears to be effective for treating pemphigus, although there are limited long-term data.

METHODS

This retrospective single-center study evaluated patients with conventional treatment-resistant pemphigus who received rituximab during September 2010-December 2019. The first rituximab cycle was based on the rheumatoid arthritis protocol in all patients except one patient, and additional single doses (500 mg or 1000 mg) were administered after clinical and/or serological relapse. The consensus definitions were used for complete remission off therapy, complete remission on minimal therapy, and clinical relapse. Serological relapse was defined as a progressive ≥2-fold increase in anti-desmoglein titers (vs. previous the measurement).

RESULTS

The study included 52 patients with pemphigus vulgaris and 1 patient with pemphigus foliaceus. The mean number of infusions was 5 and the average follow-up after the first infusion was 56 months. The average time to clinical and/or serological relapse was 12 months. Complete remission was achieved in 84.9% of patients, including after the first rituximab cycle in 25 patients (47.1%). Two patients died during the follow-up period.

CONCLUSION

Additional rituximab cycles may help achieve and prolong remission in patients with moderate-to-severe pemphigus resistant to conventional therapies. However, prospective trials are needed to identify the optimal dosing protocol.

Rituximab Therapy for Treatment of Pemphigus in Southeast Asians

Background

Rituximab provides more effective and less adverse effects than the standard dose of corticosteroids, but evidence on its efficacy and safety in the Thai population is lacking.

Objective

To evaluate the efficacy and safety of rituximab in the treatment of pemphigus and also to determine prognostic factors linked to the treatment outcomes.

Methods

Pemphigus patients who received rituximab from November 2017 to December 2020 were retrospectively reviewed. The outcome was evaluated by using early (end of consolidation phase [ECP]) and late endpoints (complete remission [CR] on/off therapy, immunological remission [IR], and relapse). Adverse events were noted. Prognostic factors associated with remission and relapse were analyzed.

Results

Of 53 pemphigus patients, all attained ECP within 1.61 months. Almost 80% achieved CR on therapy within a median time of 6.36 months, while 33.9% reached CR off therapy in 19.74 months. Nearly half had IR within a median time of 6.88 months. Relapse occurred in 33.3% with a median time of 14 months. In multivariate analysis, receiving rituximab within 12 months of disease duration was more likely to achieve CR off therapy and IR (hazard ratio [HR] 3.79; 95% confidence interval [CI] 1.38, 10.42; P = 0.01 and HR 2.74; 95% CI 1.12, 6.69; P = 0.027, respectively), whereas older patients and positive anti-desmoglein 1 levels at the time of CR were predictive indicators for relapse (HR 1.07; 95% CI 1.01, 1.13; P = 0.036 and HR 4.38; 95% CI 1.24, 15.46; P = 0.022, respectively). The treatment-related adverse effects occurred in 33.9%.

Conclusion

Rituximab is effective and safe in Thai pemphigus patients. Early administration of rituximab was a predictor of clinical and immunological remission. Older age and persistently positive anti-Dsg1 were correlated with disease relapse.

Pulmonary Nocardiosis in Pemphigus Vulgaris Patients from Tehran, Iran

OBJECTIVE

Nocardiosis is an opportunistic infection in individuals who had organ transplants and in patients with immunosuppressive diseases such as pemphigus Vulgaris (PV), diabetes mellitus, and HIV. Nocardiosis rate has not been assessed in Iranian PV patients, and this was the first study to estimate nocardiosis rate in these patients.

METHODS

In this study, 103 patients with PV were examined. BAL samples were obtained and direct smear was prepared and visualized by microscopy after PAS staining. Samples were cultured on antibiotic-containing blood and chocolate agar media. DNA extraction and PCR were performed on positive cultures, and final identification was done by 16S rRNA gene sequencing. Drug susceptibility testing was done by microbroth dilution method.

RESULTS

Four positive cultures (3.88%) were found in the samples (n = 103). According to sequence analysis, 2 isolates were identified as Nocardia cyriacigeorgica and 2 as Nocardia otitidiscaviarum and Nocardia cerradoensis. Nocardia cerradoensis was isolated from an invasive brain infection. Isolated bacteria were susceptible to majority of the tested antibiotics, except for 2 strains of Nocardia cyriacigeorgica and Nocardia cerradoensis. This was the first isolation of Nocardia cerradoensis of human infection in Asia. Patients with PV are susceptible to nocardiosis, similar to other immunocompromised patients.

CONCLUSION

Pemphigus Vulgaris is a severe autoimmune disease which is treated by a high dosage of corticosteroids. Opportunistic infections are one of the greatest challenges of these patients. One of the neglected agents of opportunistic infection in this disorder is Nocardiosis which can cause a high mortality rate in PV patients.

The evolving role of rituximab in the treatment of pemphigus vulgaris: a comprehensive state-of-the-art review

INTRODUCTION

Pemphigus vulgaris (PV) is a life-threatening autoimmune mucocutaneous blistering disease. Systemic corticosteroids (CS), while life-saving, have several serious side effects. To improve treatment and prognosis, recently rituximab (RTX), a chimeric monoclonal antibody against CD20 molecule on B cells, has become popular. This Expert Opinion discusses clinical and scientifically relevant aspects of RTX treating PV.

AREA COVERED

This presentation describes the mechanism of action, clinical efficacy, safety, adverse events, protocols used, and clinical outcomes. Concerns for infection, reactivation of latent or previous infections, and high relapse rate are discussed.

EXPERT OPINION

Use of RTX in PV is still a work in progress. There are many unanswered questions. FDA did not provide a protocol or guidelines. Whenever RTX is used, systemic corticosteroids are simultaneously used, albeit for a shorter duration and lower dose. Used in these doses for these durations they can cause immunosuppression. Would it be more appropriate if instead of 'First Line Therapy' it would be more advisable to use the term 'First Adjunctive Immunosuppressive Agent'?

A Comparative Study to Evaluate the Efficacy and Cost of Rituximab versus Dexamethasone Cyclophosphamide Pulse in Patients of Pemphigus Vulgaris

Introduction:

Rituximab is slowly getting recognized as a promising steroid-sparing agent in the treatment of moderate to severe cases of pemphigus vulgaris (PV). We evaluated and compared the effectiveness, safety, and cost of therapy of rituximab versus dexamethasone cyclophosphamide pulse (DCP) in Indian patients with PV.

Materials and Methods:

It is a retrospective data analysis, from the Immunobullous disease clinic in a tertiary centre of eastern India, of management of PV. In our institute we use either rituximab or DCP for the management of moderate to severe cases of PV, depending on that we retrospectively divided the treated cases of PV in two groups. Patients who were treated with rheumatoid arthritis (RA) protocol of rituximab were considered to be group 1. Patients who were treated with DCP were included in group 2. Response was assessed by pemphigus area, and activity score (PAAS), Dermatology life quality index (DLQI); photographic documentation, and blood parameters were monitored.

Results:

Both groups showed significant improvement in PAAS and DLQI, the improvement was faster and well sustained in the rituximab group. In terms of safety and development of new vesicles, rituximab had a better profile with only 1 patient having adverse effects and none with new vesicles as compared to DCP (3 had adverse effects and 2 developed new vesicles).

Conclusions:

Rituximab offers the advantage of early and prolonged remission, lesser adverse effects, better effectiveness, less risk of relapses, faster improvement of PAAS, and DLQI. Though rituximab is an expensive drug, but on evaluating the cost of whole therapy, it was seen that rituximab infusions are actually cheaper compared to DCP pulse. We suggest, rituximab can be used as the first-line of therapy for pemphigus vulgaris in the Indian context.

Clinical and biological activity of rituximab in the treatment of pemphigus

B-cells are major effector cells in autoimmunity since they differentiate into plasmocytes that produce pathogenic auto-antibody such as anti-desmoglein antibodies in pemphigus patients. Major advances were obtained using whole B-cell depleting therapies including anti-CD20 antibodies in refractory pemphigus patients that lead to rituximab approval in pemphigus patients in EU and USA. This review summarizes the data supporting the efficacy of rituximab in pemphigus and provides an overview of the reported immunological changes underlying its therapeutic action. Short and long-term remission in pemphigus is explained by the removal of autoreactive B-cells involved in the production of pathogenic IgG auto-antibodies and by enhancement of the appearance of regulatory B-cells that could maintain long term immune tolerance.

Rituximab in practice: Clinical evaluation of patients with pemphigus after rituximab administration

Pemphigus Vulgaris (PV) is a rare autoimmune blistering disease, which mainly causes mucosal and/or cutaneous lesions. In June 2018, FDA approved Rituximab (RTX)-a B-cell depleting agent-for the management of patients with moderate-to-severe pemphigus. Although the majority of patients respond well to this drug, some do not reach complete remission with a single cycle of RTX. In this review, following an overview of RTX and its clinical outcomes, we have focused on the possible outcomes after RTX therapy in patients with PV. The response is defined into four main categories; complete responders, partial responders, nonresponders, and paradoxical reactions, based on three possibilities of reaching the consolidation phase after 3 months, reaching remission until 6 months, and the ability of corticosteroid tapering in 6 months after RTX administration. Concerning the safety of RTX, three categories of infusion reactions, short and long-term side effects are discussed. Additionally, we have suggested approaches for the evaluation of clinical and serological responses at different critical time-points, including 1, 2, 3, and 6 months after RTX administration. Finally, available markers to predict the response to RTX and research gaps in the field of RTX therapy have been summarized.

Nocardiosis in a patient with pemphigus foliaceus treated with rituximab

Rituximab is a chimeric human/murine monoclonal anti-CD20 antibody. This agent is an effective therapeutic option in severe types of pemphigus. However, rituximab may cause opportunistic infections if used in immunosuppressed patients. We reported a case of diffuse Nocardia infection following rituximab treatment in pemphigus foliaceus. Rheumatoid arthritis protocol applied in our patient. Rituximab was used at a dose of 1000 mg every 2 weeks. Because the disease was not adequately controlled, rituximab treatment was administered six times every 15 days. One week after the sixth dose of the rituximab, she presented lassitude and multiple palpable masses in soft tissue of the upper extremity. Thereafter, the aspirate culture of the abscess on the left shoulder was taken and confirmed to be disseminated nocardiosis. She was treated with linezolid and meropenem for 1 month; however, amikacin was added because the patient did not respond adequately to linezolid and meropenem therapy. The patient died of cardiac arrest because of her comorbidities. In this case, prolonged administration of rituximab therapy may have caused the development of nocardiosis. Therefore, all patients should have a sensible balance of risk and benefit, considering the use of rituximab.

Autoimmune mucocutaneous blistering diseases in the south of Italy: a 25-year retrospective study on 169 patients

BACKGROUND

Autoimmune mucocutaneous blistering diseases (AMBDs) represent a heterogeneous group of organ-specific and potentially life-threatening diseases. We sought to determine the relationship between clinical remission and therapeutic regimens with clinical type and phenotype of AMBDs, as well as clinical outcomes achieved based on different therapeutic regimens.

METHODS

A retrospective single-center study on 169 AMBDs patients, including pemphigus vulgaris (PV), mucous membrane pemphigoid (MMP), paraneoplastic autoimmune multiorgan syndrome (PAMS), and lichen planus pemphigoides (LPP), was performed from 1994 to 2019 in an oral medicine tertiary center, where we collected sociodemographic data, clinical type and phenotype, prescribed therapies, and related outcomes.

RESULTS

The mean age of AMBDs patients was 55.0 ± 16.4 years. They were followed for a mean of 8.4 ± 5.8 years. The majority of these patients (62.1%) were successfully managed with conventional immunosuppressive therapy (CIST) alone. However, 37.9% of patients required additional biological treatments, either because they were non-responders or developed severe side effects from CIST, or because of the rapid and severe progression of the disease. Overall, complete clinical remission was achieved in 92.3% of patients. A statistically significant difference was noted between the frequency distribution of AMBDs patients among different therapeutic regimens (P = .002), of different clinical phenotype and type of AMBDs patients and clinical remission (P = .012 and P = .005, respectively). No difference was reported regarding clinical outcomes and different therapeutic regimens.

CONCLUSIONS

AMBDs' management may be challenging, nonetheless CIST and biologic regimens introduced, when needed as reliable alternatives to CIST, result in a very high percentage of CCR.

Rituximab: A Review in Pemphigus Vulgaris

Rituximab (MabThera^®, Rituxan^®), a chimeric murine/human anti-CD20 monoclonal antibody administered by intravenous infusion, is indicated for the treatment of moderate to severe pemphigus vulgaris (PV), in combination with a tapering course of corticosteroids. Approval in the EU and USA was based on data for the subset of patients with newly-diagnosed, previously untreated PV participating in the randomized, controlled RITUX 3 study; rituximab plus short-course prednisone resulted in a > 3-fold higher rate of complete remission off prednisone therapy and a > 2-fold decrease in the rate of moderate/severe relapse compared with standard-dose prednisone in this patient subpopulation. In addition, rituximab plus short-term prednisone was steroid-sparing and resulted in fewer patients experiencing grade 3 or 4 corticosteroid-related adverse events compared with standard-dose prednisone. The adverse event profile of rituximab in patients with PV was consistent with that observed for the drug in other approved autoimmune disorders; no new safety concerns were identified. Notwithstanding there is some uncertainty over the optimum dosing schedule to achieve and maintain disease control, rituximab is a highly effective and generally well tolerated, steroid-sparing treatment for moderate to severe PV.

Post-rituximab immunoglobulin M (IgM) hypogammaglobulinemia

Rituximab is a B cell depleting monoclonal antibody that targets the B cell-specific cell surface antigen CD20 and is currently used to treat several autoimmune diseases. The elimination of mature CD20-positive B lymphocytes committed to differentiate into autoantibody-producing plasma cells is considered to be the major effect of rituximab, that makes it a beneficial biological agent in treating autoimmune diseases. Hypogammaglobulinemia has been reported after rituximab therapy in patients with lymphoma and rheumatoid arthritis. Similar data are scarce for other autoimmune diseases. Low immunoglobulin G (IgG) or hypogammaglobulinemia has attracted the most attention because of its significant role in protective immunity. However, the incidence and clinical implications of low immunoglobulin M (IgM) or hypogammaglobulinemia have not been studied in detail. This review will focus on the frequency and the clinical concerns of low IgM levels that result as a consequence of the administration of rituximab. The etiopathogenic mechanisms underlying post-rituximab IgM hypogammaglobulinemia and its implications are presented. The long-term consequences, if any, are not known or documented. Multiple factors may be involved in whether IgG or IgM decreases secondary to rituximab therapy. It is possible that the autoimmune disease itself may be one of the important factors. The dose, frequency and number of infusions appear to be important variables. Post-rituximab therapy immunoglobulin levels return to normal. During this process. IgM levels take a longer time to return to normal levels when compared to IgG or other immunoglobulins. IgM deficiency persists after B cell repopulation to normal levels has occurred. Laboratory animals and humans deficient in IgM can have multiple infections. Specific pharmacologic agents or biologic therapy that address and resolve IgM deficiency are currently unavailable. If the clinical situation so warrants, then prophylactic antibiotics may be indicated and perhaps helpful. Research in this iatrogenic phenomenon will provide a better understanding of not only the biology of IgM, but also the factor(s) that control its production and regulation, besides its influence if any, on rituximab therapy.

Treatment of pemphigus vulgaris: part 2 - emerging therapies

Introduction: Corticosteroids and immunosuppressive agents have been the mainstay for the treatment of pemphigus vulgaris (PV). While they have benefited patients, they have been associated with the risks of prolonged immune suppression and a high incidence of significant and catastrophic side effects. Relapses are common. Novel agents promising targeted therapies, that may provide better outcomes, are being studied. Areas covered: Recently rituximab with corticosteroids has been recommended as the first-line treatment for PV. A number of known and new therapeutic agents currently investigated are BAFF, P13K, BTK inhibitors along with the use of IVIg and CAR-T therapy. The possible role of these therapeutic targets in the pathophysiology appears to be the rationale for the treatment of this potentially fatal disease. Expert opinion: While there is significant enthusiasm for these therapies, certain concerns and consequences are being under-discussed. None of the current clinical trials in progress are specific for PV, except possibly CAR-T therapy. The major issue(s) that are unclear is whether these therapies would be successful in providing long-term clinical remissions. Will these therapies require additional agents to be effective? Will the benefits be limited in duration? The answers to many questions will determine their final place in the algorithm for the treatment of PV.

Pemphigus

Pemphigus consists of a group of rare and severe autoimmune blistering diseases mediated by pathogenic autoantibodies mainly directed against two desmosomal adhesion proteins, desmoglein (Dsg)1 and Dsg3 (also known as DG1 and DG3), which are present in the skin and surface-close mucosae. The binding of autoantibodies to Dsg proteins induces a separation of neighbouring keratinocytes, in a process known as acantholysis. The two main pemphigus variants are pemphigus vulgaris, which often originates with painful oral erosions, and pemphigus foliaceus, which is characterised by exclusive skin lesions. Pemphigus is diagnosed on the basis of either IgG or complement component 3 deposits (or both) at the keratinocyte cell membrane, detected by direct immunofluorescence microscopy of a perilesional biopsy, with serum anti-Dsg1 or anti-Dsg3 antibodies (or both) detected by ELISA. Corticosteroids are the therapeutic mainstay, which have recently been complemented by the anti-CD20 antibody rituximab in moderate and severe disease. Rituximab induces complete remission off therapy in 90% of patients, despite rapid tapering of corticosteroids, thus allowing for a major corticosteroid-sparing effect and a halved number of adverse events related to corticosteroids.

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.

Identification of Autoreactive B Cell Subpopulations in Peripheral Blood of Autoimmune Patients With Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a rare blistering disease caused by IgG autoantibodies against the epidermal adhesion molecules desmoglein (Dsg)3 and Dsg1 providing a well-characterized paradigm of an antibody-mediated organ-specific autoimmune disease. In PV patients who have achieved clinical remission after B cell-depleting therapy, relapses often coincide with a reoccurrence of B cells and Dsg-specific autoantibodies. Here, we analyzed Dsg3-specific B cell subpopulations (i.e., total CD19⁺ B cells, CD19⁺CD27⁻B cells, CD19⁺CD27⁺ memory B cells, and CD19⁺CD27^hiCD38^hi plasmablasts) in peripheral blood of both PV patients (n = 14) at different stages of disease and healthy individuals (n = 14) by flow cytometry using fluorescently labeled recombinant human Dsg3 protein. Applying this approach, Dsg3-specific B cells could be detected at low frequencies (0.11–0.53% of CD19⁺ B cells) and numbers of Dsg3-specific memory B cells were significantly increased in PV patients in clinical remission receiving minimal immunosuppressive therapy. Finally, we confirmed in vitro that Dsg3-reactive memory B cells were able to produce anti-Dsg3 IgG autoantibodies upon ex vivo activation. Thus, monitoring of Dsg3-specific B cells in PV is of particular interest to further characterize the immunopathogenesis of PV.

Rituximab as a dual therapeutic option for pemphigus and primary cutaneous B-cell lymphomas: Two case reports

It is known that individuals with immune dysregulation have an increased risk of non-Hodgkin lymphoma. This association has been proven for pemphigus as well as for other autoimmune disease. We describe the development of cutaneous B-cell lymphoma in two patients affected by long-standing pemphigus vulgaris and pemphigus foliaceus (i.e., characterized by histological and immunopathological features different from those of paraneoplastic pemphigus). In both cases, a therapy with rituximab allowed to achieve the complete remission for the lymphoproliferative disease (never recurred at follow up) and a substantial long-term improvement of the clinical manifestations of pemphigus, although persistent to serological disease and occasional recurrences. We suggest that clinicians should consider that patients with long-standing pemphigus, both vulgaris and foliaceus, may develop primary cutaneous B-cell lymphomas, as shown in our report, and in these cases the treatment with rituximab is elective, providing a therapeutic option for both low-grade or follicular, CD20-positive, B-cell non-Hodgkin lymphomas and pemphigus. Nevertheless, as shown in our cases, a constant surveillance for pemphigus is necessary.

[Therapy of pemphigus]

BACKGROUND

Pemphigus diseases are a heterogeneous group of potentially life-threatening autoimmune bullous disorders. Therefore, rapidly acting and effective therapeutic approaches are essential.

OBJECTIVES

In this review, current therapeutic options in line with available guidelines are presented and new therapeutic approaches are discussed.

METHODS

A literature search was performed using PubMed.

RESULTS

Treatment of pemphigus is based on systemic glucocorticosteroids, frequently combined with potentially corticosteroid-sparing immunosuppressants such as azathioprine and mycophenolate mofetil/mycophenolic acid. Recently, the impressive efficacy of the anti-CD20 antibody rituximab has been shown in a prospective randomized trial. In severe or treatment-refractory cases, immunoadsorption or high-dose intravenous immunoglobulins (IVIG) are recommended. Adjuvant immunoadsorption also seems to be useful within the first 8-12 weeks of therapy in patients with very high autoantibody levels. A variety of new therapeutic approaches is currently evaluated in phase IIa studies.

CONCLUSION

Therapy of pemphigus has been greatly improved by the employment of rituximab. The use of glucocorticosteroids, associated with a high number of adverse events and elevated mortality, could be reduced by the additional use of rituximab. After approval of rituximab for the treatment of pemphigus by the US Food and Drug Administration in 2018, licensing in Europe is expected in 2019.

Pemphigus and mucous membrane pemphigoid: An update from diagnosis to therapy

Pemphigus diseases (PDs) and mucous membrane pemphigoid (MMP) are a group of immune-mediated mucocutaneous disorders clinically characterized by the formation of blisters, erosions and ulcers. The skin and mucous membranes are predominantly affected, with the oropharyngeal mucosa as the initially involved site. Ocular involvement is also a frequent feature of these diseases. Because of the considerable overlap in their clinical presentations, the diagnosis of PDs vs. MMP can be challenging. A recognition of their specific immunological and histopathologic features is crucial in the differential diagnosis. Treatment modalities include systemically administered corticosteroids, steroid-sparing immunosuppressive agents, and biologic therapies (rituximab, intravenous immunoglobulins, and anti-tumor necrosis factor agents). Topical, oral, conjunctival, or intralesional corticosteroids as well as anti-inflammatory drugs and antibiotics are prescribed as needed.

Mucosal involvement is a risk factor for poor clinical outcomes and relapse in patients with pemphigus treated with rituximab

Many studies have reported the outcome of rituximab use in pemphigus but studies regarding the clinical risk factors for poor clinical outcomes or relapse are lacking. To clarify the risk factors for poor clinical outcomes or relapse in patients with pemphigus treated with rituximab, a retrospective chart analysis was performed on patients with pemphigus who were treated with rituximab in the dermatology clinic of Seoul National University Hospital. Forty patients with pemphigus were treated with rituximab, of which 39 (97.5%) experienced remission and 19 (48.7%) experienced relapse. Patients with mucosal lesions demonstrated poor clinical outcomes. The risk for relapse was 4.626 (confidence interval: 1.126-19.001, p = .034) times higher in patients with mucosal lesions than in those without lesions. In patients with pemphigus treated with rituximab, the presence of mucosal lesions resulted in poor clinical outcomes and frequent recurrence.

[Immunoadsorption in dermatology]

Autoimmmune bullous diseases are mediated by pathogenetically relevant autoantibodies against components of the epidermis and/or superficial mucous membranes (in pemphigus) and structural proteins of the dermal-epidermal junction (in pemphigoid diseases). Using immunoadsorption (IA), an already well-established procedure in cardiac and rheumatic disorders, antibodies can be removed from the plasma. At present, most data on the adjuvant use of IA in dermatology are derived from patients with severe and/or refractory pemphigus vulgaris or pemphigus foliaceus and also from patients with pemphigoid diseases. Additionally, in the last few years different protocols for IA in patients with severe atopic dermatitis and elevated total serum IgE levels have been published. While panimmunoglobulin adsorbers are mainly used in dermatology, an IgE-specific adsorber has been used in some patients with atopic dermatitis and in the future, antigen-specific adsorbers are to be expected that will enable the specific reduction of autoantibodies.

Pemphigus Foliaceus-Repeated Treatment With Rituximab 7 Years After Initial Response: A Case Report

Pemphigus foliaceus is an autoimmune skin disease mediated by autoantibodies directed against desmoglein-1 located in the upper epidermal layer. Rituximab, a monoclonal anit-CD20 antibody depleting b-cells, offers an effective treatment possibility for therapy-resistant pemphigus foliaceus. Here, we present the case of 55-year-old man who did not respond sufficiently to conventional treatment with prednisolone, azathioprine, and cyclophosphamide, but underwent almost complete remission after rituximab treatment. The patient relapsed 7 years later, and a repeated course of rituximab infusions led to a partial remission.

Rituximab in pemphigus

Pemphigus is a severe autoimmune blistering disease mediated by pathogenic anti-desmoglein antibodies leading to an inter keratinocyte disjunction. Rituximab is a monoclonal antibody that binds to the CD-20 antigen of B lymphocytes, which causes B-cell depletion and a subsequent reduction in pathogenic autoantibodies. Its therapeutic role in pemphigus has been progressively growing with increasing evidence of successful outcomes. Rituximab was initially off-labeled used as an alternative in patients with recalcitrant or relapsing pemphigus and in patients with contraindications to systemic corticosteroids. Recently, a large randomized clinical trial has shown that first-line use of rituximab combined with short-term prednisone regimen was both more effective and potentially safer than a standard regimen of high doses of corticosteroids in patients with moderate to severe pemphigus.

Shifting Focus in the Therapeutics of Immunobullous Disease

Therapeutics of autoimmune bullous disease has seen a major shift of focus from more global immunosuppression to targeted immunotherapy. Anti CD 20 monoclonal antibody Rituximab revolutionized the therapeutics of autoimmune bullous disease particularly pemphigus. Though it is still being practiced off-label, evidences in the form of RCT and meta analysis are now available. Other novel anti CD 20 monoclonal antibodies like ofatumumab, veltuzumab, and ocrelizumab, tositumomab or obinutuzumab/GA101 may add to the therapeutic options in coming days. Beyond anti CD 20 monoclonal antibodies other options that show promise at least in select scenario are omalizumab, TNF inhibitors plasmapheresis and intravenous immunoglobulin. The present article will discuss the role of rituximab and other newer therapeutics in the treatment of autoimmune blistering disease, especially pemphigus and suggests their positions in the therapeutic ladder.