Novel applications of Rituximab in dermatological disorders

Repurposing of rituximab biosimilars to treat B cell mediated autoimmune diseases

Rituximab, the first monoclonal antibody approved for the treatment of lymphoma, eventually became one of the most popular and versatile drugs ever in terms of clinical application and revenue. Since its patent expiration, and consequently, the loss of exclusivity of the original biologic, its repurposing as an off-label drug has increased dramatically, propelled by the development and commercialization of its many biosimilars. Currently, rituximab is prescribed worldwide to treat a vast range of autoimmune diseases mediated by B cells. Here, we present a comprehensive overview of rituximab repurposing in 115 autoimmune diseases across 17 medical specialties, sourced from over 1530 publications. Our work highlights the extent of its off-label use and clinical benefits, underlining the success of rituximab repurposing for both common and orphan immune-related diseases. We discuss the scientific mechanism associated with its clinical efficacy and provide additional indications for which rituximab could be investigated. Our study presents rituximab as a flagship example of drug repurposing owing to its central role in targeting cluster of differentiate 20 positive (CD20) B cells in 115 autoimmune diseases.

Rituximab in Pemphigus Vulgaris: A Review of Monoclonal Antibody Therapy in Dermatology

Pemphigus vulgaris (PV) is a rare autoimmune blistering disorder that primarily affects the skin and mucous membranes. Conventional treatments for PV, such as corticosteroids and immunosuppressive agents, have limitations in terms of efficacy and long-term safety. Monoclonal antibody therapy, specifically rituximab, has emerged as a promising therapeutic approach in the management of PV. This review article provides a comprehensive overview of rituximab in the treatment of PV, with a focus on its efficacy, safety profile, and immunological mechanisms of action. The article begins with an introduction to PV and the significance of monoclonal antibody therapy in dermatology. It then explores the clinical presentation and underlying immune-mediated mechanisms of PV, highlighting the autoimmune nature of the disease. The rationale for using monoclonal antibody therapy, particularly rituximab, in PV is discussed, emphasizing the limitations of conventional treatments and the concept of targeted therapy. The review delves into the efficacy and safety of rituximab based on clinical studies, evaluating disease remission rates, duration, and relapse rates. Furthermore, the immunological effects of rituximab, including B-cell depletion and modulation of the immune response, are explored in detail. Comparisons between rituximab and conventional treatment modalities in PV are made, assessing clinical outcomes, safety profiles, and long-term efficacy. Challenges and considerations in rituximab therapy are discussed, including factors influencing its efficacy, optimal dosing, treatment duration, and the need for maintenance therapy.

The Impact of Immune-Modulating Treatments for Dermatological Diseases on the Risk of Infection with SARS-CoV-2 and Outcomes Associated with COVID-19 Illness

Purpose of Review

Immune-modulating treatments are used in dermatology for a variety of conditions. The authors aim to review the data regarding the safety of these treatments during the COVID-19 pandemic, namely the risk of infection with SARS-CoV-2 and the outcomes associated with COVID-19-related illness.

Recent Findings

Several large-scale studies found no increased risk of COVID-19 infection for patients on TNF-α inhibitors, IL-17 inhibitors, IL-12/23 inhibitors, IL-23 inhibitors, dupilumab, and methotrexate. They also found that these patients did not have worse outcomes when infected with COVID-19. The data regarding JAK inhibitors, rituximab, prednisone, cyclosporine, mycophenolate mofetil, and azathioprine are more mixed.

Summary

Based on current research and guidelines from the American Academy of Dermatology and the National Psoriasis Foundation, dermatology patients on immune-modulating therapies can continue treatment during the COVID-19 pandemic when they are not infected with SARS-CoV-2. For patients who have COVID-19, guidelines encourage individualized assessment of the benefits and risks of continuing or temporarily withholding treatment.

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.

B cell modulation strategies in the improvement of transplantation outcomes

Successful transplantation outcome is the final goal in most end stage and nonfunctional organs; however, despite using different therapeutic strategies, antibody-mediated rejection is still a big obstacle. B cells have a key role in transplant rejection by several functions, such as antibody production, antigen presenting, contribution in T cell activation, forming the germinal center, and tertiary lymphoid organs. Therefore, B cells modulation seems to be very crucial in transplant outcome. A double-edged sword function is considered for B cells during transplantation; On the one hand, antibody production against the transplanted organ induces antibody-mediated rejection. On the other hand, IL10 production by regulatory B (Breg) cells induces graft tolerance. Nowadays, several monoclonal antibodies (mAb) are available for B cell modulation that are routinely used in transplant recipients, among which rituximab (anti-CD20 mAb) act in eliminating B cells. However, there are some other monoclonal antibodies, such as epratuzumab and Inotuzumab ozogamicin (IO), which exert anti-CD22 activity, resulting in disruption of B cell functions and induction of tolerance in autoimmune disease or B cell malignancies; that notwithstanding, these mAbs have not yet been tried in transplantation. In this review, we focus on different methods for modulating the activity of B cells as well as induction of Breg cells, aiming to prevent the allograft rejection.

Rituximab for refractory subcutaneous Sweet's syndrome in chronic lymphocytic leukemia: A case report

Sweet's syndrome is a neutrophilic dermatosis characterised by sudden onset of fever, neutrophilia, erythematous skin rashes and neutrophilic infiltration of the dermis. Subcutaneous Sweet's syndrome, or Sweet's panniculitis, is an uncommon variant of the classic syndrome, with hypodermal neutrophilic infiltration. The association of Sweet's syndrome with various malignancies has been reported. The most common underlying hematological malignancies are of myeloid origin; however, there have been several reports of the classic Sweet's syndrome in patients with a lymphoproliferative disorder, although the association of subcutaneous Sweet's syndrome with lymphoproliferative disorders has not been well-documented thus far. Herein, we present the case of a 48-year-old man with a 2-year history of chronic lymphocytic leukemia who developed fever and skin rashes, without any evidence of a relapse. The clinical and pathological investigation resulted in the diagnosis of subcutaneous Sweet's syndrome. The patient exhibited no significant response to conventional therapeutic measures; however, following two subsequent doses of rituximab, his general condition and skin rash improved. The follow-up skin biopsy demonstrated dermal neutrophilic infiltrations in conjunction with prior mixed lobular and septal panniculitis, suggesting evolution of subcutaneous Sweet's syndrome to its classic form. To the best of our knowledge, this is one of the first reports of rituximab as a novel biological treatment for Sweet's syndrome. However, further randomized trials are required to evaluate the efficacy and safety of such biological therapies for Sweet's syndrome.