Current therapy of granulomatosis with polyangiitis and microscopic polyangiitis: the role of rituximab.
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ABSTRACT: Granulomatosis with polyangiitis and microscopic polyangiitis are anti-neutrophil cytoplasmic antibody-associated vasculitides (AAVs) that are prone to cycles of remission and relapse. The introduction of cytotoxic therapy has changed the prognosis for these diseases from typically fatal to manageable chronic illnesses with a relapsing course. Despite improvements in outcomes, recurrence of disease and drug-related toxicity continue to produce significant morbidity and mortality. Better understanding of the pathogenesis of AAV and the mechanism of action of cyclophosphamide has led to investigation of therapies that target B cells. Two randomized controlled trials have shown that rituximab is not inferior to cyclophosphamide for induction of remission in severe AAV, with no significant difference in the incidence of overall adverse events in rituximab- versus cyclophosphamide-treated patients. Data from ongoing clinical trials will determine the role of rituximab in the maintenance of remission.
Project description:Granulomatosis with polyangiitis and microscopic polyangiitis are small vessel vasculitides characterized by circulating antineutrophil circulating antibodies. Standard treatment for active severe disease has consisted of cyclophosphamide with glucocorticoids with or without plasmapheresis, which achieves approximately 75% sustained remission, but carries significant adverse effects such as malignancy, infertility, leukopenia, and infections. The role of B cells in the pathogenesis of anti-neutrophil circulating antibodies-associated vasculitis has been established, and as such, rituximab, a monoclonal anti-CD20 antibody, has been studied in treatment of active granulomatosis with polyangiitis and microscopic polyangiitis (induction) and in maintaining remission. Rituximab has been shown to be effective in inducing remission in several retrospective studies in patients with refractory disease or cyclophosphamide intolerance. The RAVE and RITUXVAS trials demonstrated rituximab is a noninferior alternative to standard cyclophosphamide-based therapy; however, its role in elderly patients and patients with severe renal disease warrants further investigation. Rituximab has been compared with azathioprine for maintaining remission in the MAINRITSAN trial and may be more efficacious in maintaining remission in patients treated with cyclophosphamide induction. Rituximab is not without risks and carries a similar adverse event risk rate as cyclophosphamide in randomized control trials. However, its use can be considered over cyclophosphamide in patients who have relapsing or refractory disease or in young patients seeking to preserve fertility.
Project description:ObjectiveThe present study was undertaken to conduct a phase IV, open-label, prospective study to characterize the long-term safety of rituximab in a 4-year observational registry of adult patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) within the US.MethodsPatients initiating treatment with rituximab were evaluated every 6 months for up to 4 years. Outcomes included the incidence of serious adverse events (SAEs), infusion-related reactions (IRRs), and SAEs of specific interest, including serious infections, serious cardiac events, serious vascular events, and malignancies.ResultsOverall, 97 patients (72 with GPA and 25 with MPA) received rituximab through a median of 8 (range 1-28) infusions and were followed up for a median of 3.94 years (range 0.05-4.32 years). The estimated incidence rates (95% confidence interval [95% CI]) of serious infections, serious cardiac events, and serious vascular events were 7.11 (4.55-10.58), 5.03 (2.93-8.06), and 2.37 (1.02-4.67) per 100 patient-years (PYs), respectively. No IRRs or SAEs occurred within 24 hours of an infusion of rituximab. None of the 9 deaths reported (crude mortality rate 2.67 [95% CI 1.22-5.06] per 100 PYs) were considered to be related to use of rituximab.ConclusionThe safety profile of long-term treatment with rituximab in patients with GPA or MPA was consistent with that of rituximab administered for shorter durations and with rituximab's known safety profile in other autoimmune diseases for which it has received regulatory approval. These findings provide clinicians with long-term, practice-level safety data for rituximab in the treatment of GPA or MPA.
Project description:PurposeThere has been no extensive study to compare the efficacy between rituximab originator (Mabthera®) and its biosimilar (Truxima®) for microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). Here, we investigated the clinical effects of rituximab on poor outcomes of MPA and GPA in Korean patients, and compared those between Mabthera® and Truxima®.Materials and methodsWe retrospectively reviewed the medical records of a total of 139 patients, including 97 MPA patients and 42 GPA patients. At diagnosis, antineutrophil cytoplasmic antibody positivity and comorbidities were assessed. During follow-up, all-cause mortality, relapse, end-stage renal disease, cerebrovascular accident and acute coronary syndrome were evaluated as poor outcomes. In this study, rituximab was used as either Mabthera® or Truxima®.ResultsThe median age at diagnosis was 60.1 years and 46 patients were men (97 MPA and 42 GPA patients). Among poor outcomes, patients receiving rituximab exhibited a significantly lower cumulative relapse-free survival rate compared to those not receiving rituximab (p=0.002). Nevertheless, rituximab use did not make any difference in other poor outcomes of MPA and GPA except for relapse, which might be a rebuttal to the fact that rituximab use after relapse eventually led to better prognosis. There were no significant differences in variables at diagnosis and during follow-up between patients receiving Mabthera® and those receiving Truxima®. Patients receiving Truxima® exhibited a similar pattern of the cumulative survival rates of each poor outcome to those receiving Mabthera®.ConclusionTruxima® prevents poor outcomes of MPA and GPA as effectively as does Mabthera®.
Project description:ObjectivesRituximab is used for remission induction and the prevention of relapse in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). This study evaluated the incidence of safety events and compared time to first serious adverse event (SAE) between a rituximab cohort and a cohort treated with non-rituximab therapies in a real-life setting.MethodsRituximab surveillance study in vasculitis was a retrospective observational study of patients with AAV who received rituximab (MabThera) or other treatments between 2003 and 2017 at a specialist vasculitis clinic. The primary endpoint was time to first SAE.Results392 patients were enrolled: 247 in the rituximab and 145 in the control cohorts with a total follow up of 2217 person-years (mean study duration 5.7 years). Mean age was 61 years, 77% had granulomatosis with polyangiitis (GPA). There were differences in baseline characteristics (disease duration and prior immunosuppressive use) between groups. 134/247 patients (54%) in the rituximab and 58/145 (40%) of controls experienced at least one SAE. Time to first SAE was shorter in the rituximab group (hazard ratio (HR) 1.55, 95% CI 1.07-2.26, P = 0.022). Predictors of first SAE were higher vasculitis damage index and the presence of chronic pulmonary or kidney disease. The risk of serious infection was higher in the rituximab group (relative risk (RR) 2.12, 95% CI 1.31-3.43).ConclusionOver 40% of patients with AAV experienced at least one SAE. Although shorter time to first SAE and higher risk of infection were observed in the rituximab group, baseline imbalances necessitate a careful interpretation of these results.
Project description:ObjectiveTo assess the safety, tolerability, pharmacokinetics, and efficacy of rituximab (RTX) in pediatric patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA).MethodsThe Pediatric Polyangiitis Rituximab Study was a phase IIa, international, open-label, single-arm study. During the initial 6-month remission-induction phase, patients received intravenous infusions of RTX (375 mg/m2 body surface area) and glucocorticoids once per week for 4 weeks. During the follow-up period, patients could receive further treatment, including RTX, for GPA or MPA. The safety, pharmacokinetics, pharmacodynamics, and exploratory efficacy outcomes with RTX were evaluated.ResultsTwenty-five pediatric patients with new-onset or relapsing disease were enrolled at 11 centers (19 with GPA [76%] and 6 with MPA [24%]). The median age was 14 years (range 6-17 years). All patients completed the remission-induction phase. During the overall study period (≤4.5 years), patients received between 4 and 28 infusions of RTX. All patients experienced ≥1 adverse event (AE), mostly grade 1 or grade 2 primarily infusion-related reactions. Seven patients experienced 10 serious AEs, and 17 patients experienced 31 infection-related AEs. No deaths were reported. RTX clearance correlated with body surface area. The body surface area-adjusted RTX dosing regimen resulted in similar exposure in both pediatric and adult patients with GPA or MPA. Remission, according to the Pediatric Vasculitis Activity Score, was achieved in 56%, 92%, and 100% of patients by months 6, 12, and 18, respectively.ConclusionIn pediatric patients with GPA or MPA, RTX is well tolerated and effective, with an overall safety profile comparable to that observed in adult patients with GPA or MPA who receive treatment with RTX. RTX is associated with a positive risk/benefit profile in pediatric patients with active GPA or MPA.
Project description:ImportanceResults of randomized clinical trials have demonstrated rituximab's noninferiority to cyclophosphamide as induction therapy for antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV), with neither treatment having a specific advantage for granulomatosis with polyangiitis (GPA). However, post hoc analysis results have suggested that rituximab might be more effective than cyclophosphamide in inducing remission in patients with proteinase 3-positive AAV.ObjectiveTo compare the effectiveness of rituximab and cyclophosphamide in inducing GPA remission in a large population of unselected patients.Design, setting, and participantsThis comparative effectiveness study used multicenter target trial emulation observational data from 32 French hospitals in the French Vasculitis Study Group Registry. Groups were determined according to treatments received, without any intervention from the investigators. Inverse probability of treatment weighting was used to correct for baseline imbalance between groups. Participants included patients with newly diagnosed or relapsing GPA who satisfied American College of Rheumatology classification criteria and/or Chapel Hill Consensus Conference nomenclature. Data were analyzed from October 1, 2021, to May 31, 2022.ExposuresAt least 1 infusion of rituximab or cyclophosphamide for induction therapy between April 1, 2008, and April 1, 2018.Main outcomes and measuresThe primary outcome was remission rate at month 6 (±2 months), with remission defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 and prednisone dose of 10 mg/d or less. The BVAS is a validated tool for small-vessel vasculitis and used to assess the level of disease activity, with a numerical weight attached to each involved organ system. The BVAS has a range of 0 to 63 points; a score of 0 indicates no disease activity. Subgroup analyses included the primary outcome for patients with a new diagnosis, for most recently treated patients, and for patients with myeloperoxidase-ANCA positivity.ResultsAmong 194 patients with GPA included in the analysis (mean [SD] age, 54 [15] years; 110 men [56.7%]), 165 (85.1%) had a new diagnosis, and 147 of 182 with data available (80.8%) had proteinase 3-ANCA positivity. Sixty-one patients received rituximab and 133 received cyclophosphamide for induction therapy. In the weighted analysis, the primary outcome was reached for 73.1% of patients receiving rituximab vs 40.1% receiving cyclophosphamide (relative risk [RR], 1.82 [95% CI, 1.22-2.73]; risk difference, 33.0% [95% CI, 12.2%-53.8%]; E value for RR, 3.05). Similar results were observed in the subgroup of patients with newly diagnosed GPA and those with a more recent treatment. In the subset of 27 patients with myeloperoxidase-ANCA-positive GPA, 8 of 10 rituximab recipients and 8 of 17 cyclophosphamide recipients met the primary end point (unweighted RR, 1.73 [95% CI, 0.96-3.11]).Conclusions and relevanceIn this comparativeness effectiveness study using clinical data, rituximab induction therapy for GPA was more frequently associated with remission than cyclophosphamide. These results inform clinical decision-making concerning the choice of remission induction therapy for this subset of patients with AAV.
Project description:Clinical trials and observational studies have established cyclophosphamide (CY) or rituximab plus glucocorticoid (GC) as standard remission induction therapies in patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). However, because these regimens are associated with serious adverse drug reactions, the development of drugs with novel mechanisms of actions are needed. Progress in basic and clinical research has identified novel candidate targeting molecules, including B-cell activating factor (BAF), C5a receptor, and interleukin-6. The combination of rituximab and BAF blockade in patients with MPA and GPA is under investigation in an effort to strike a better benefit-risk balance. Phase II clinical trials of avacopan (CCX168), an orally administered C5a receptor antagonist, have suggested a reduction in the dosage of concomitant GC or the replacement of GC in patients with MPA and GPA. The results from a currently ongoing phase III trial are awaited. Anecdotal case reports and an open-label pilot study have indicated the effectiveness of tocilizumab in patients with MPA and GPA. A randomized clinical trial comparing tocilizumab and intravenous CY in combination with GC is currently in progress. Molecular targeted therapy is expected to transform the treatment strategy for MPA and GPA to allow GC-free or at least less GC-dependent forms of therapy.
Project description:Anti-neutrophil cytoplasmic antibody-associated vasculitides granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) are rare, potentially organ- and life-threatening autoimmune conditions affecting adult and pediatric patients. An open-label phase II study was conducted to determine safe and effective dosing regimens of rituximab in pediatric patients with GPA/MPA. To determine the selection of an appropriate dose regimen in children for induction and maintenance, a population pharmacokinetic approach was used (nonlinear mixed-effect modeling), combining pediatric data with data from adults with GPA/MPA. The time course of B-cell depletion was assessed in both populations. The exposure-effect relationship was assessed by logistic regression. Twenty-five pediatric patients (80% female patients; age range, 6-17 years) were enrolled in the trial and received the induction regimen of intravenous rituximab 375 mg/m2 weekly for 4 weeks, which resulted in a similar exposure to that of adults. Based on pharmacokinetic modeling, a maintenance dosing regimen of 250 mg/m2 administered twice over 14 days followed by 250 mg/m2 every 6 months is expected to result in similar rituximab exposure as that of adults receiving the approved maintenance dose of 500 mg administered twice over 14 days followed by 500 mg every 6 months. The time course of B-cell depletion was similar between the pediatric and adult populations, supporting the similarities in response in both populations and allowing extrapolation to patients less than 6 years old. Using a partial extrapolation approach helped identify safe and effective dosing regimens of rituximab in pediatric patients with GPA/MPA and lead to regulatory approval.
Project description:IntroductionThe aim of this work was to assess the impact of prolonged low immunoglobulin (IgG or IgM) serum concentrations on the potential cumulative serious infection (SI) risk in pediatric patients following rituximab treatment for granulomatosis with polyangiitis or microscopic polyangiitis (GPA/MPA) in PePRS.MethodsPatients aged ≥ 2 to < 18 years received four weekly intravenous rituximab infusions of 375 mg/m2 and concomitant glucocorticoid taper. After 6 months, patients could receive further rituximab and/or other immunosuppressants per investigator discretion. Immunoglobulin levels and SIs were assessed throughout the 4.5-year observation period. Prolonged low IgG or IgM was defined as below the lower limit of normal age-specific reference range for ≥ 4 months.ResultsA total of 25 patients were included, of whom 19 (76%) had GPA and six (24%) had MPA; 18 (72%) had newly diagnosed disease and seven (28%) had relapsing disease. All 25 patients completed the rituximab induction regimen; 24 completed ≥ 18 months of follow-up. At month 18, eighteen patients (72%) had prolonged low IgG; 19 (76%), prolonged low IgM; and 15 (60%), both. Seven patients (28%) had nine SIs; one occurred during or after prolonged low IgG only, two during or after prolonged low IgM only, and six during or after concurrent prolonged low IgG and IgM. No patients died or discontinued the study due to SI. All patients had complete and sustained peripheral B-cell depletion for ≥ 6 months.ConclusionsThe majority of pediatric patients who received rituximab for GPA/MPA with prolonged low immunoglobulin levels did not experience SIs. In patients with SIs, these events were manageable, and the number of SIs did not increase over time or with multiple rituximab treatments. These observations are consistent with the rituximab safety profile in adults with GPA/MPA.Trial registrationClinicalTrials.gov identifier, NCT01750697.
Project description:PurposeThe present study compared the efficacy of mycophenolate mofetil (MMF) with that of azathioprine (AZA) in Korean patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA).Materials and methodsThe medical records of 69 patients with MPA and GPA who received cyclophosphamide and subsequently received AZA or MMF for remission maintenance therapy were reviewed. All-cause mortality, relapse, end-stage renal disease (ESRD), cerebrovascular accident, and cardiovascular disease were evaluated as poor outcomes. Having a lower Birmingham Vasculitis Activity Score (BVAS) was defined as the lowest tertile of BVAS (BVAS ≤11 in this study).ResultsIn comparative analysis of the occurrence of poor outcomes among patients taking AZA only, MMF only, and MMF after AZA, patients taking MMF only exhibited a significantly lower cumulative ESRD-free survival rate than patients taking AZA only (p=0.028). In terms of ESRD occurrence between the groups based on BVAS at diagnosis, among patients with MPA and GPA with higher BVAS at diagnosis, patients taking MMF only exhibited a significantly lower cumulative ESRD-free survival rate than those taking AZA only (p=0.047). Among patients with MPA and GPA with the lowest tertile of BVAS at diagnosis, cumulative ESRD-free survival rates did not differ.ConclusionWith regard to ESRD occurrence, the efficacy of MMF in remission maintenance therapy was less effective than AZA in patients with MPA and GPA. However, among patients with lower BVAS, there was no difference in the occurrence of poor outcomes between patients taking MMF and those taking AZA.