Clinical experiences of different dosing schedules of rituximab in pemphigus with various disease severities

The efficacy and safety of low-dose rituximab in the treatment of pemphigus vulgaris: a cohort study

BACKGROUND

Rituximab (RTX) is considered the first-line treatment for pemphigus vulgaris (PV), which is a B-cell-mediated acquired autoimmune disease. However, no consensus on the optimum dosage has been achieved.

OBJECTIVES

To investigate the efficacy and safety of low-dose RTX (a single infusion of 500 mg) for the treatment of PV, a cohort study was conducted for patients with PV, along with a 12-month follow-up following the administration of RTX.

METHODS

Patients with moderate or severe PV were divided into group A (low-dose RTX combined with corticosteroids) and group B (corticosteroids alone). Data on complete remission (CR) rates, doses of corticosteroids, cumulative doses of corticosteroids at the third, sixth, and twelfth months, pemphigus disease area index and adverse effects (AEs) were collected.

RESULTS

Forty-four patients with moderate or severe PV were enrolled in this study (19 in group A and 25 in group B). Patients treated with low-dose RTX had higher CR rates, lower doses of corticosteroids at the third, sixth, and twelfth months, lower cumulative doses of corticosteroids at the sixth and twelfth months, and fewer AEs than those who received corticosteroids alone.

CONCLUSIONS

This study indicated that low-dose RTX may be a beneficial and secure therapy option for patients with moderate to severe PV.

Is It Time to Reconsider Rituximab Dosing Regimens for Pemphigus Vulgaris?

Rituximab is currently approved for patients affected by moderate-to-severe pemphigus vulgaris, a severe autoimmune blistering skin disease that can be life-threatening. The standard rituximab dosing regimens, originally established for B-cell non-Hodgkin's lymphomas, have been recognized to exceed the effective dose required for inducing B-cell depletion, considering that the B-cell burden in pemphigus vulgaris is considerably lower than in lymphoproliferative disorders. We herein report our experience with very ultra-low-dose rituximab in two patients affected by pemphigus vulgaris.

Cost-Utility Analysis of Rituximab vs Mycophenolate Mofetil for the Treatment of Pemphigus Vulgaris

Importance

There is an increasing body of literature that supports the use of rituximab as a first-line steroid-sparing agent in pemphigus vulgaris. However, the cost of rituximab is substantial compared with conventional agents, and there are limited health economic data to justify its use.

Objective

To evaluate the cost-effectiveness of rituximab biosimilars relative to mycophenolate mofetil as a first-line steroid-sparing agent for moderate to severe pemphigus vulgaris.

Design, Setting, and Participants

A cost-utility analysis over a 24-month time horizon was conducted from the perspective of the Australian health care sector using a modeled cohort of treatment-naive adult patients with moderate to severe pemphigus vulgaris. A Markov cohort model was constructed to simulate disease progression following first-line treatment with rituximab biosimilars or mycophenolate mofetil. The simulated cohort transitioned between controlled disease, uncontrolled disease, and death. Efficacy and utility data were obtained from available published literature. Cost data were primarily obtained from published government data. One-way and probabilistic sensitivity analyses were performed to assess uncertainty. Primary outcomes were the changes in cost and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) over the 24 months.

Interventions

Rituximab biosimilars and mycophenolate mofetil.

Results

The simulated cohort of treatment-naive patients had a mean age of 50.8 years, a female-to-male ratio of 1.24, and moderate to severe disease as classified by the Harman criteria. First-line rituximab biosimilars were associated with a cost reduction of AU$639 and an improvement of 0.07 QALYs compared with mycophenolate mofetil, resulting in an ICER of -AU$8818/QALY. Rituximab biosimilars were therefore more effective and less costly compared with mycophenolate mofetil. Sensitivity analyses demonstrated that rituximab biosimilars remained cost-effective across a range of values for cost, utility, and transition probability input parameters and willingness-to-pay thresholds.

Conclusions and Relevance

In this cost-utility analysis, rituximab biosimilars were cost-effective compared with mycophenolate mofetil for moderate to severe pemphigus vulgaris. Further investigation into its cost-effectiveness over a longer time horizon is necessary, but the favorable results of this study suggest that the high acquisition costs of rituximab biosimilars may be offset by its effectiveness and provide economic evidence in support of its listing on the Pharmaceutical Benefits Scheme for pemphigus vulgaris.

Role of Rituximab in the Treatment of Pemphigus Vulgaris: Patient Selection and Acceptability

Anti-CD20 monoclonal antibody rituximab is an approved adjuvant treatment, in combination with oral corticosteroids, for patients with pemphigus vulgaris, a severe and potentially life-threatening autoimmune blistering skin disorder. Updated approaches to the management of pemphigus vulgaris support rituximab as a first-line adjuvant treatment to induce remission early in the course of disease; however, its feasibility in the clinical setting is often reduced by a series of limitations, including high cost of this biological drug, physician and patient concern for the risk of adverse reactions, and uncertainty regarding the optimum dosing and schedule of administration. The standard approved rituximab dosages, which are derived from lymphoma protocols, have been recognized to exceed the effective dose required for inducing B cell depletion, since the B cell burden in pemphigus vulgaris is much lower than in lymphoproliferative disorders. To overcome these limitations, recent research has investigated alternative regimens of rituximab, using lower doses of the drug. Moreover, differences in patient and disease characteristics that are highlighted in the literature strongly suggest that therapy should be tailored individually on a case-by-case basis: personalized treatment schedules may be necessary to optimize response to treatment and tolerability in different subjects, with the possibility of repeated infusions for severe forms and in case of relapse. Finally, low-dose regimens of rituximab were suggested to be favorable during the COVID-19 pandemic by providing a lesser degree of immune cell depletion while retaining a sufficient response. In conclusion, the current literature suggests that lower-dose regimens of rituximab are not only tolerable and cost-effective but may also be associated with a positive response in pemphigus vulgaris, comparable to that achieved with higher doses especially in early disease. Further evidence from rigorous clinical trials will be required to optimize lower-dose regimens of RTX and establish their position within the treatment scenario of pemphigus vulgaris.

The demographic attributes, clinical features, and optimal management of 143 patients with pemphigus: A retrospective observational study from a tertiary care center of India

Background:

This retrospective study was to understand the clinico-epidemiologic and therapeutic aspects of pemphigus patients attending our clinic.

Methods:

We analyzed charts of 143 (M: F; 51:92) pemphigus patients having variable severity recorded between 2009 and 2019. Therapies were customized based on patient's age, disease severity, comorbidities, compliance prospects, and affordability. The patients were monitored monthly and as needed for therapeutic outcome in terms of disease control, reduced hospitalization, remission/relapse, and drug toxicity.

Results:

These patients were aged 15 to 86 years, the majority, 68 (47.5%), was 41 to 60 years of age. The pemphigus vulgaris in 83.9% patients was the commonest variant. Treatment regimens were; dexamethasone-cyclophosphamide-pulse (DCP) therapy in 51.2%, dexamethasone-azathioprine-pulse (DAP) therapy in 11%, dexamethasone-pulse (DP) therapy in 5.5%, rituximab in 24.4%, IVIg in 5.5% patients, and oral corticosteroids with or without adjuvant. Remission occurred after 2–17 (mean 5.8) DCP doses; 14 and 7 patients achieved remission for ≥2 y and ≥5 y, respectively. Rituximab was effective to treat both new and relapsed cases (n = 31). Additional treatment with another adjuvant prolonged remission in seven patients relapsed 12–16 months after treatment with rituximab alone. Overall, oral corticosteroids alone and DAP therapy showed unsatisfactory response. Adverse effects seen in 41.9% of patients were mainly corticosteroids related.

Conclusion:

The overall clinico-epidemiologic spectrum of pemphigus and therapeutic efficacy of DCP, DAP, or corticosteroids in this study was in sync with the literature. Combining rituximab and corticosteroids plus an immunomodulator initially (phase-1), followed by immunomodulator alone for one year (phase-2) will improve long-term (phase-3) therapeutic outcome. IVIg was effectively useful in patients with concurrent infections.

Real world evidence: Patients with refractory pemphigus treated with Rituximab

BACKGROUND

Pemphigus is a group of autoimmune blistering diseases, potentially life-threatening. Rituximab received FDA approval in June 2018 for the treatment of moderate to severe pemphigus vulgaris.

OBJECTIVES

To evaluate the efficacy and safety of rituximab in patients with pemphigus, resistant to previous therapies or unable to receive classic immunosuppressive treatment due to serious adverse events or comorbidities.

MATERIALS AND METHODS

Twenty-five patients (9 men, 16 women), mean age 49.4 ± 15.9 years (range 21-74 years), mean disease duration 4 ± 2.7 years (range 0.25-10 years) were included in the study: 19 patients with pemphigus vulgaris and 6 with pemphigus foliaceous. The efficacy of rituximab was evaluated according to the control of disease, retention of remission, disease severity, previous treatments and adverse reactions. During COVID-19 pandemic patients are monitored closely through tele-dermatology.

RESULTS

Twenty-three out of 25 patients had great improvement, 2 out of 25 ceased therapy due to adverse events (arthralgias and dyspnea). Sixteen out of 23 received additional course after 8 months (range 5-60 months). More aged patients presented more frequently adverse events and underwent additional courses (p = 0.002). Rituximab was found superior to classic immunosuppressive treatment in terms of efficacy and safety, with larger periods of remission and lower doses of corticosteroids and immunosuppressants. No major adverse events were noticed.

CONCLUSIONS

Rituximab is a very effective treatment of pemphigus and, remarkably, superior to classic immunosuppressive treatment.

A systematic review on efficacy, safety, and treatment-durability of low-dose rituximab for the treatment of Pemphigus: special focus on COVID-19 pandemic concerns

BACKGROUND

Rituximab is a FDA-approved monoclonal antibody for adults with moderate to severe potentially life-threatening pemphigus vulgaris. Recent studies have focused on assessments of efficacy and safety of low-dose rituximab (<2 gram in each cycle).

METHOD

Databases were searched from 2010 to 2020 (last update: 1 June 2020).

RESULT

Nine studies were entered; including180 cases (92: women, 88: men, age range: 9-83 years). The dosages of each Rituximab cycle varied between ultra-low-dose (≤500 mg for a cycle, either multiple infusions or a single infusion), low-dose (2 × 375 mg/m² or 2 × 500 mg) and modified-dose (3 × 375 mg/m² or 3 × 500 mg). The efficacy and safety of Rituximab in the studies are known by the recovery time, relapse time, and side events. According to the studies, 2 × 500 can lead to complete remission in a broad range, from 35 to 82%. These differences might be explained by different end-points and variable cumulative corticosteroid dosage after RTX administration. Although the studies showed that low dose RTX is efficient, there are some controversies regarding the choosing low-dose for severe patients.

CONCLUSION

Considering the effectiveness of low-dose, intermediate dose, and ultra-low-dose protocols of Rituximab in inducing remission in pemphigus disease and considering factors such as cost of therapy, and the need to induce a minimum of immunosuppression for a minimum duration in the COVID-19 pandemic, suggested to use low-dose Rituximab protocol (2 infusions of 500 mg Rituximab: interval of 2 weeks) to induce the remission in mild-to-moderate pemphigus patients.

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.

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.

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.

Rituximab: A Magic Bullet for Pemphigus

INTRODUCTION

Pemphigus, an autoimmune disease, was fatal before the era of corticosteroids. With the advent of steroids, mortality decreased but morbidity was present due to the side effects of high dose steroids. Newer drugs targeted at the molecular level are said to have fewer side effects and improved effectiveness.

AIM

The aim of our study was to assess the effectiveness of one such drug, Rituximab, a biological, in treating pemphigus vulgaris and to identify common adverse events.

MATERIALS AND METHODS

It was an open label prospective interventional study, conducted from September 2013 to May 2015, in the Department of Dermatology, Stanley Medical College, Chennai, Tamil Nadu, India. Twenty patients with pemphigus were included in the study. Ten were refractory to conventional therapy and 10, new cases. Patients who satisfied inclusion and exclusion criteria were included in the study after informed, written consent. Rituximab was administered according to Rheumatoid arthritis protocol. The patients were followed up as out patients after discharge, end points and adverse events were noted.

RESULTS

There were 14 females (70%) and six males (30%). The mean age of the study group was 41.35 years. The mean disease duration was 11.7 months. The mean duration of follow up being 14.25 months. After rituximab, 13 patients remained in remission for varying periods of 3-22 months. The mean duration of complete remission off- treatment with Dexamethasone Cyclophosphamide Pulse (DCP) was 3.6 months; with rituximab it was 8.8 months. Seven (35%) patients relapsed during the study of whom six had received rituximab after being refractory to conventional treatment. Patients who relapsed had higher mean disease duration (21 months) than the remission group (6.384 months). Two patients (10%) developed immediate adverse events. Six patients (30%) developed late adverse events the commonest being reactivation of herpes labialis.

CONCLUSION

Rituximab was effective in treating pemphigus vulgaris, was significantly better than conventional treatment, decreased the need for additional steroids and other immunosuppressants and induced prolonged remission. Rituximab was more effective when given early in the disease process. Further studies may highlight the need for additional cycles of rituximab to maintain sustained remission.

p38 MAPK Signaling in Pemphigus: Implications for Skin Autoimmunity

p38 mitogen activated protein kinase (p38 MAPK) signaling plays a major role in the modulation of immune-mediated inflammatory responses and therefore has been linked with several autoimmune diseases. The extent of the involvement of p38 MAPK in the pathogenesis of autoimmune blistering diseases has started to emerge, but whether it pays a critical role is a matter of debate. The activity of p38 MAPK has been studied in great detail during the loss of keratinocyte cell-cell adhesions and the development of pemphigus vulgaris (PV) and pemphigus foliaceus (PF). These diseases are characterised by autoantibodies targeting desmogleins (Dsg). Whether autoantibody-antigen interactions can trigger signaling pathways (such as p38 MAPK) that are tightly linked to the secretion of inflammatory mediators which may perpetuate inflammation and tissue damage in pemphigus remains unclear. Yet, the ability of p38 MAPK inhibitors to block activation of the proapoptotic proteinase caspase-3 suggests that the induction of apoptosis may be a consequence of p38 MAPK activation during acantholysis in PV. This review discusses the current evidence for the role of p38 MAPK in the pathogenesis of pemphigus. We will also present data relating to the targeting of these cascades as a means of therapeutic intervention.