Rituximab in autoimmune pemphigoid diseases: Indications, optimized regimens, and practice gaps

Advancements in Bullous Pemphigoid Treatment: A Comprehensive Pipeline Update

ABASTRACT

Bullous pemphigoid (BP) is a common autoimmune bullous disease affecting mainly the elderly, with rising incidence due to increased life expectancy. This disease is characterized by tense bullous lesions on normal or erythematous skin, accompanied by pruritus. BP pathogenesis involves autoantibodies against hemidesmosomal proteins BP180 and BP230, leading to detachment at the dermo-epidermal junction as well as blister formation. BP is associated with coexisting comorbidities and drug exposure, and its management often requires high doses or chronic use of systemic glucocorticoids, posing risks of adverse effects. This review focuses on novel treatment options for BP, exploring therapies targeting different immune pathways. Rituximab, a CD20 monoclonal antibody, depletes B-lymphocytes and has shown efficacy in severe cases. Dupilumab, targeting interleukin (IL)-4 receptor α and thus blocking IL-4 and IL-13, downregulates type 2 helper (Th2) responses and has demonstrated promising results. Targeting eosinophil-related molecules using bertilimumab and AKST4290 has yielded positive results in clinical trials. Omalizumab, an immunoglobulin (Ig) E antibody, can reduce disease severity and allows corticosteroid tapering in a number of cases. Complement inhibitors such as nomacopan and avdoralimab are being investigated. IL-17 and IL-23 inhibitors such as secukinumab and tildrakizumab have shown potential in a limited number of case reports. Neonatal Fc receptor antagonists such as efgartigimod are under investigation. Additionally, topical therapies and Janus kinase inhibitors are being explored as potential treatments for BP. These novel therapies offer promising alternatives for managing BP, with potential to improve outcomes and reduce high cumulative doses of systemic corticosteroids and related toxicities. Further research, including controlled clinical trials, is needed to establish their efficacy, safety, and optimal dosing regimens for BP management.

Review of an Anti-CD20 Monoclonal Antibody for the Treatment of Autoimmune Diseases of the Skin

Biologic therapies targeting B-cells are emerging as an effective strategy to treat a variety of immune-mediated diseases. One of the most studied B-cell-targeted therapies is rituximab, an anti-CD20 monoclonal antibody that exemplifies B-cell depletion therapy and has served as the prototype for other anti-CD20 monoclonal antibodies and the development of biosimilars. While there are multiple studies on the use of rituximab in dermatology, a comprehensive review of rituximab therapy in autoimmune skin conditions is lacking. In this literature review, we summarize indications, treatment efficacy, and safety of rituximab among common autoimmune diseases of the skin: pemphigus vulgaris, cutaneous lupus erythematous, dermatomyositis, systemic sclerosis, thyroid dermopathy, autoimmune pemphigoid diseases, and cutaneous vasculitis diseases. Existing data on rituximab support the approach of rituximab, biosimilars, and newer B-cell-targeting therapies in immune-mediated cutaneous diseases. Overall, rituximab, which targets CD20, provides an effective alternative or concomitant option to traditional immunosuppressants in the management of various autoimmune diseases of the skin. Further studies are necessary to expand the understanding and possible utility of B-cell-targeted therapies among autoimmune skin diseases.

Off-Label Uses of Rituximab in Dermatology

Purpose of Review

Rituximab has transformed the treatment of B-cell malignancies and rheumatoid arthritis in the past 2 decades. More recently, this anti-CD20 monoclonal antibody has seen increasing usage in the field of dermatology. This review highlights the evidence supporting its use in several important dermatologic conditions.

Recent Findings

Key recent findings include the 2018 FDA approval of rituximab for the treatment of moderate-to-severe pemphigus.

Summary

Data from randomized controlled trials have demonstrated the efficacy of rituximab in pemphigus, ANCA-associated vasculitis, and cryoglobulinemic vasculitis. More limited data suggests its use in recalcitrant cases of diseases such as pemphigoid, epidermolysis bullosa acquisita, and dermatomyositis. There is scarce evidence and mixed results for rituximab when studied in cutaneous polyarteritis nodosa and cutaneous lupus erythematosus.

Rituximab in Mucous Membrane Pemphigoid: A Monocentric Retrospective Study in 10 Patients with Severe/Refractory Disease

Rituximab (RTX) is a monoclonal antibody directed against CD20 antigen indicated in an increasing number of immune-mediated diseases. While its efficacy in pemphigus vulgaris has been widely investigated, only a few data about its possible role in pemphigoid diseases have been reported in the literature. Accordingly, herein we evaluated a case series of patients with mucous membrane pemphigoid (MMP) treated with RTX. We included patients with a history of severe/refractory MMP who received at least one cycle of intravenous RTX between May 2018 and December 2021 and had 6 months of follow-up time. Disease control (DC) was our early endpoint, while complete remission (CR) and partial remission (PR) were late endpoints. CR off-therapy, relapses, and adverse events were evaluated as well. Our population included 10 MMP patients. Eight out of ten patients (80%) achieved DC in a mean of 8 weeks, while two patients with ocular MMP were non-responders. Among the eight patients who achieved DC, two reached CR off therapy, two CR on minimal therapy, and two achieved PR on minimal therapy. In our case series, the addition of RTX to conventional therapies was demonstrated to be safe and effective in reaching rapid disease control in the majority of refractory MMP patients.

Clinical Effectiveness and Safety of Initial Combination Therapy with Corticosteroids and Rituximab in Bullous Pemphigoid: A Retrospective Cohort Study

BACKGROUND

Rituximab is a potential initial adjuvant therapy for bullous pemphigoid, yet clinical experience is scarce.

OBJECTIVE

We aimed to examine the clinical outcomes and safety of initial combination therapy with systemic corticosteroids and adjuvant rituximab for the treatment of bullous pemphigoid.

METHODS

A retrospective cohort study was performed on 84 patients with bullous pemphigoid, who received systemic corticosteroids with or without initial adjuvant rituximab therapy (defined as rituximab use within 12 weeks after initiation of systemic corticosteroids).

RESULTS

Among the 84 patients included (37 received systemic corticosteroids with rituximab and 47 were treated with systemic corticosteroids without rituximab), the median time to complete remission on minimal therapy or off therapy was 215 days (95% confidence interval 176.9-253.1) in patients receiving rituximab vs 529 days (95% confidence interval 338.6-719.4) in those not receiving rituximab. A Cox regression analysis showed an increased probability of reaching complete remission on minimal therapy or off therapy with the combined therapy (hazard ratio = 2.28 [1.28-4.07], p = 0.005) after age, Bullous Pemphigoid Disease Activity Index score, and underlying diseases were controlled. In multivariate logistic/linear regressions, initial adjuvant rituximab therapy was associated with a higher complete remission rate (odds ratio = 6.63 [2.09-21.03]) and lower cumulative prednisolone (mg)/body weight (kg) (B = -24.86 [-44.06 to -8.29]) within 48 weeks. Risk of hospitalization for infection was not elevated in the group treated with adjuvant rituximab.

CONCLUSIONS

Rituximab use as adjuvant therapy within 12 weeks after initiation of systemic corticosteroids was associated with a faster and higher rate of achieving complete remission on minimal therapy or off therapy, as well as a significant corticosteroid-sparing effect and a comparable safety profile in this retrospective study. Hence, initial combination therapy with corticosteroids and adjuvant rituximab could serve as an effective treatment option for bullous pemphigoid, but this requires confirmation in randomized controlled studies.

Omalizumab for the Treatment of Bullous Pemphigoid: A Systematic Review of Efficacy and Safety

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Current treatment strategies are limited by their efficacy and/or side effect profile and the need for safer and effective alternatives is undeniable. We aimed to conduct a systematic review focusing on the efficacy and safety of omalizumab in BP patients. Embase, PubMed, Cochrane, and clinicaltrials.gov were searched for English and French articles published from inception to July 1, 2021, using search terms "omalizumab" OR "Xolair" OR "IGE025" OR "olizumab" AND "bullous pemphigoid." Screening and data extraction was performed by two raters independently. The primary outcome was complete response (CR), and secondary outcomes were partial response (PR), flare-ups, adverse events/vital status. In total, 22 articles were included, with a total of 56 patients. All patients had a refractory BP with mean disease duration of 13.5 ± 20.2 months (Standard Deviation (SD)) and failed 3.1 ± 1.6 therapies and many remained corticosteroids dependent. Overall, 87.5% of patients responded to treatment (55.4% CR and 32.1% PR), 7.1% discontinued the protocol and only 5.4% were non responders. A third of patients were able to discontinue all other therapies and most others were able to discontinue or taper systemic corticosteroids to <10 mg daily. Flare-ups occurred in 57.7% of patients upon discontinuation of omalizumab and/or steroid tapering, most patients recaptured response thereafter. Omalizumab was well tolerated by most patients. Omalizumab appears to be a promising treatment for BP with a good response rate and safety profile. However, several limitations were identified in current literature, and highlight the need for randomized controlled trials of omalizumab in BP.

Bullous Pemphigoid Associated With Pembrolizumab Therapy for Non-Small-Cell Lung Cancer: A Case Report

Pembrolizumab is an immune checkpoint inhibitor being increasingly used as immunotherapy for a multitude of cancers. With the increasing use of these agents, various immune-related adverse events are being recognized. Lichenoid reaction, pruritus, and eczema are well-established cutaneous side effects of pembrolizumab, but bullous pemphigoid (BP) is a rare side effect of the drug. It is difficult to establish this diagnosis because it needs a detailed history of the timeline of the evolution of symptoms and careful ruling out of other etiologies, especially other drugs. Here, we present the case of a 66-year-old male who developed BP after receiving pembrolizumab therapy for non-small-cell lung cancer. Discontinuation of pembrolizumab and the use of topical and systemic steroids led to the complete resolution of symptoms. Physicians should be aware of this potential complication and keep it on their differential diagnosis when treating patients on immune checkpoint inhibitors.

Ocular mucous membrane pemphigoid: novel treatment strategies

PURPOSE OF REVIEW

To describe current treatments of ocular mucous membrane pemphigoid (OMMP), including conventional systemic immunosuppression (CIST) and novel biologic agents.

RECENT FINDINGS

CIST remains the main stay therapy for the management of OMMP. The choice of agents is tailored to disease severity - mild disease is treated with dapsone, whereas moderately severe cases are often treated with mycophenolate mofetil or sulfa-based drugs and severe cases are treated with cyclophosphamide. In recalcitrant disease newer biologics such as Rituximab, intravenous immunoglobins and tumour necrosis alpha antagonists have proven to be effective in disease control. Control of inflammation with topical therapy and halting conjunctival fibrosis remain as areas of unmet clinical needs.

SUMMARY

OMMP is largely treated with CIST. The recent introduction of new biologic agents could shape the way the disease is treated in the near future.

A retrospective cohort study reporting rituximab treatment for 33 patients with immunobullous disease

BACKGROUND

Autoimmune bullous disorders, encompassing pemphigus and pemphigoid diseases, are associated with significant morbidity and mortality. This is in part due to high cumulative doses of corticosteroids in combination with immunosuppressant agents used in traditional treatment regimes. Rituximab is an antiCD20 monoclonal antibody which can induce complete remission, but it is currently unlicensed in the UK and approved only after other treatments have failed.

METHODS

We report a retrospective cohort study of 33 patients with pemphigus and pemphigoid diseases treated with rituximab from a single tertiary centre from 2013 to 2019.

RESULTS

"Complete remission off therapy" was achieved by 27.3% (n = 9), and a further 27.3% (n = 9) had complete remission on minimal therapy. Twenty-one per cent (n = 7) had "partial remission on minimal therapy"; 9.1% (n = 3) patients were in the "consolidation phase," and 12.1% (n = 4) had a "relapse/flare." A steady reduction in prednisolone doses was observed post-Rituximab infusion. Pre-Rituximab the median dose of prednisolone was 20mg (range 10-35, IQR 25), 15mg (range 9.5-22.5, IQR 13) at 1 month, 9mg (range 5-10, IQR 5) at 6 months, 4mg (range 0-5mg, IQR 5) at 12 months and 0 (0-4.35, IQR 4.25) at 18 months. Twelve per cent (n = 4) of patients had documented infusion reaction symptoms. Twelve per cent (n = 4) had later infective complications.

CONCLUSION

This real clinic data adds to the evidence that Rituximab is a safe and effective treatment for both pemphigus and pemphigoid autoimmune blistering conditions. Significantly, we were able to demonstrate a substantial reduction in corticosteroid dosage in our cohort of patients following rituximab treatment.