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Objective: B‐cell depletion using the anti‐CD20 monoclonal antibody rituximab is a cornerstone in the therapeutic concept of multiple autoimmune diseases. B‐cell depletion is associated with a higher risk for severe infections, and the time span of B‐cell repopulation differs greatly between individuals. Data on factors influencing B‐cell repopulation kinetics are limited. This study aims to identify patient‐specific and therapy‐associated covariates that modulate B‐cell repopulation. Methods: This single‐center retrospective observational study presents data of 839 subjects receiving 2,017 courses of rituximab for autoimmune diseases. Assessed covariates are patient‐specific factors (sex, age, kidney function, and underlying disease) and co‐immunosuppression with common agents (azathioprine, cyclosporine A, cyclophosphamide, hydroxychloroquine, methotrexate, mycophenolate mofetil, tacrolimus, and corticosteroids). The primary end point is the time to B‐cell repopulation (≥5/μl). The secondary end point is the time to B‐cell reconstitution (≥50/μl). Multivariate time‐to‐event analysis and logistic regression models were applied to estimate the influence of covariates. Results: Age over 60 years (hazard ratio [HR] 0.71 for repopulation, P = 0.008), impaired kidney function (HR 0.72, P = 0.001), antineutrophil cytoplasmic antibody‐associated vasculitis (HR 0.61, P < 0.001), solid organ transplantation (HR 0.4, P < 0.001), and co‐immunosuppression with corticosteroids (HR 0.64, P < 0.001) or azathioprine (HR 0.49, P < 0.001) were associated with impaired B‐cell repopulation and reconstitution. Effects of corticosteroids (P = 0.043) and azathioprine (P = 0.025) were dose dependent. Conclusion: Prolonged rituximab dosing intervals may be effective to achieve B‐cell depletion and reduce risk of infection in advanced age or patients with impaired kidney function. Co‐medication with corticosteroids or azathioprine prolongs B‐cell recovery, which may increase therapeutic effects but also the rate of adverse events. [ABSTRACT FROM AUTHOR]

Objective: To compare rituximab‐ versus cyclophosphamide‐based remission induction strategies for the long‐term risks of kidney failure and death in antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) in a real‐world cohort. Methods: We performed a cohort study using the Mass General Brigham AAV Cohort, which includes proteinase 3–ANCA+ and myeloperoxidase (MPO)‐ANCA+ AAV patients diagnosed from January 1, 2002 to December 31, 2019. We included cases in which the initial remission induction strategy was based either on rituximab or cyclophosphamide. The primary outcome was the composite outcome of kidney failure or death. We used multivariable Cox proportional hazards models and propensity score–matched analyses to assess the association of rituximab‐ versus cyclophosphamide‐based treatment strategies with the composite outcome of kidney failure or death. Results: Of 595 included patients, 352 patients (~60%) received rituximab‐based and 243 patients (~40%) received cyclophosphamide‐based regimens. The mean age was 61 years, 58% of patients were female, 70% of patients were MPO‐ANCA+, and 69% of patients had renal involvement (median estimated glomerular filtration rate 37.3 ml/minute/1.73 m2). There were 133 events at 5 years, and the incidence rates in rituximab‐ and cyclophosphamide‐based regimens were 6.8 and 6.1 per 100 person‐years, respectively. The risk of kidney failure or death was similar in both groups in multivariable‐adjusted analyses (hazard ratio [HR] 1.03 [95% confidence interval (95% CI) 0.55–1.93]) and in propensity score–matched analyses (HR 1.05 [95% CI 0.55–1.99]) at 5 years. Our findings were similar when outcomes were assessed at 1 and 2 years as well as in subgroups stratified according to renal involvement and severity as well as major organ involvement. Conclusion: Rituximab‐ and cyclophosphamide‐based remission induction strategies for AAV are associated with similar risks of kidney failure and death. [ABSTRACT FROM AUTHOR]

Objective: To assess the safety, mechanism of action, and preliminary efficacy of rituximab followed by belimumab in the treatment of refractory lupus nephritis (LN). Methods: In a multicenter, randomized, open‐label clinical trial, 43 patients with recurrent or refractory LN were treated with rituximab, cyclophosphamide (CYC), and glucocorticoids followed by weekly belimumab infusions until week 48 (RCB group), or treated with rituximab and CYC but no belimumab infusions (RC group). Patients were followed up until week 96. Percentages of total and autoreactive B cell subsets in the patients' peripheral blood were analyzed by flow cytometry. Results: Treatment with belimumab did not increase the incidence of adverse events in patients with refractory LN. At week 48, a complete or partial renal response occurred in 11 (52%) of 21 patients receiving belimumab, compared to 9 (41%) of 22 patients in the RC group who did not receive belimumab (P = 0.452). Lack of improvement in or worsening of LN was the major reason for treatment failure. B cell depletion occurred in both groups, but the percentage of B cells remained lower in those receiving belimumab (geometric mean number of B cells at week 60, 53 cells/μl in the RCB group versus 11 cells/μl in the RC group; P = 0.0012). Percentages of total and autoreactive transitional B cells increased from baseline to week 48 in both groups. However, percentages of total and autoreactive naive B cells decreased from baseline to week 48 in the belimumab group compared to the no belimumab RC group (P = 0.0349), a finding that is consistent with the observed impaired maturation of naive B cells and enhanced censoring of autoreactive B cells. Conclusion: The addition of belimumab to a treatment regimen with rituximab and CYC was safe in patients with refractory LN. This regimen diminished maturation of transitional to naive B cells during B cell reconstitution, and enhanced the negative selection of autoreactive B cells. Clinical efficacy was not improved with rituximab and CYC in combination with belimumab when compared to a therapeutic strategy of B cell depletion alone in patients with LN. [ABSTRACT FROM AUTHOR]

Objective S100A8/A9 (calprotectin) has shown promise as a biomarker for predicting relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was undertaken to investigate serum S100A8/A9 level as a biomarker for predicting future relapse in a large cohort of patients with severe AAV. Methods Serum levels of S100A8/A9 were measured at baseline and months 1, 2, and 6 following treatment initiation in 144 patients in the Rituximab in ANCA-Associated Vasculitis trial (cyclophosphamide/azathioprine versus rituximab [RTX] for induction of remission) in whom complete remission was attained. Results Patients were divided into 4 groups: proteinase 3 (PR3)-ANCA with relapse (n = 37), PR3-ANCA without relapse (n = 56), myeloperoxidase (MPO)-ANCA with relapse (n = 6), and MPO-ANCA without relapse (n = 45). Serum S100A8/A9 level decreased in all groups during the first 6 months of treatment. The percentage reduction from baseline to month 2 was significantly different between patients who experienced a relapse and those who did not in the PR3-ANCA group ( P = 0.046). A significantly higher risk of relapse was associated with an increase in S100A8/A9 level between baseline and month 2 ( P = 0.0043) and baseline and month 6 ( P = 0.0029). Subgroup analysis demonstrated that patients treated with RTX who had increased levels of S100A8/A9 were at greatest risk of future relapse ( P = 0.028). Conclusion An increase in serum S100A8/A9 level by month 2 or 6 compared to baseline identifies a subgroup of PR3-ANCA patients treated with RTX who are at higher risk of relapse by 18 months. Since RTX is increasingly used for remission induction in PR3-ANCA-positive patients experiencing a relapse, S100A8/A9 level may assist in identifying those patients requiring more intensive or prolonged treatment. [ABSTRACT FROM AUTHOR]

Objective The Rituximab in ANCA-Associated Vasculitis (RAVE) trial compared rituximab to cyclophosphamide as induction therapy for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We undertook the current study to determine whether known single-nucleotide polymorphisms (SNPs) for Fcγ receptors (FcγR) or cytochrome P450 (CYP) enzymes were associated with the response to treatment with rituximab and cyclophosphamide, respectively. Methods Functional SNPs for FcγR (FcγRIIa 519G>A, FcγRIIb 695T>C, FcγRIIIa 559T>G) and CYP enzymes (CYP2B6 1459C>T, CYP2C19 681G>A) were analyzed by direct sequencing of polymerase chain reaction-amplified genomic DNA. Each SNP was tested as a predictor of complete remission at 6 months or remission with continued prednisone administration using logistic regression and including the covariates of baseline Birmingham Vasculitis Activity Score for Wegener's Granulomatosis, ANCA type, and new versus relapsing disease. The associations of these SNPs with the secondary outcomes of time to complete remission, time to relapse, or time to B cell reconstitution were analyzed by Cox proportional hazard tests. Results No significant associations were identified between complete remission and any FcγR genotype in the rituximab group or any CYP genotype in the cyclophosphamide group. However, when the treatment groups were combined, an association was found between the 519AA genotype of FcγRIIa and complete remission ( P = 0.01). The 519AA genotype predicted complete remission ( P = 0.006) and a shorter time to complete remission ( P < 0.001). Conclusion The finding that the homozygous FcγRIIa 519AA variant was associated with complete response and a shorter time to complete response in the RAVE trial, independent of treatment type, implies that FcγRIIa may be broadly involved in disease pathogenesis and response to therapy. [ABSTRACT FROM AUTHOR]

Objective To identify predictors of respiratory failure and to evaluate the therapeutic efficacy of plasma exchange (PE) and of rituximab versus cyclophosphamide in a cohort of patients with diffuse alveolar hemorrhage (DAH) secondary to antineutrophil cytoplasmic antibody-associated vasculitis (AAV) with or without respiratory failure. Methods We performed a single-center historical cohort study of all consecutive patients with AAV-associated DAH who were evaluated over a 16-year period. Logistic regression models were developed to examine the predictive role of the baseline clinical characteristics for the development of respiratory failure, and for the effect of PE and remission induction therapy on the main outcome (complete remission at 6 months). Results Seventy-three patients with DAH were identified, and 34 of them experienced respiratory failure. The degree of hypoxemia upon initial presentation, a higher percentage of neutrophils in the bronchoalveolar lavage fluid cell count, and higher C-reactive protein levels were independently associated with the development of respiratory failure. PE was not associated with achieving complete remission at 6 months, with an odds ratio (OR) of 0.49 (95% confidence interval [95% CI] 0.12-1.95) ( P = 0.32). Rituximab treatment was independently associated with achieving complete remission at 6 months (OR 6.45 [95% CI 1.78-29], P = 0.003). Conclusion Our findings indicate that the most important predictor of respiratory failure in patients with DAH secondary to AAV is the degree of hypoxemia upon presentation. No clear benefit of the addition of PE to standard remission induction therapy was demonstrated. Complete remission by 6 months was achieved at a higher rate with rituximab than with cyclophosphamide in patients with DAH secondary to AAV, including those needing mechanical ventilation. [ABSTRACT FROM AUTHOR]

Objective Nonsevere relapses are more common than severe relapses in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but their clinical course and treatment outcomes remain largely unexamined. We undertook this study to analyze the outcomes of patients with nonsevere relapses in the Rituximab in ANCA-Associated Vasculitis (RAVE) trial who were treated with prednisone according to a prespecified protocol. Methods RAVE was a randomized, double-blind, placebo-controlled trial comparing rituximab (RTX) to cyclophosphamide (CYC) followed by azathioprine (AZA) for induction of remission. Patients who experienced nonsevere relapses between months 1 and 18 were treated with a prednisone increase without a concomitant change in their nonglucocorticoid immunosuppressants, followed by a taper. Results Forty-four patients with a first nonsevere relapse were analyzed. In comparison to the 71 patients who maintained relapse-free remission over 18 months, these patients were more likely to have proteinase 3-ANCAs, diagnoses of granulomatosis with polyangiitis (Wegener's), and a history of relapsing disease at baseline. A prednisone increase led to remission in 35 patients (80%). However, only 13 patients (30%) were able to maintain second remissions through the followup period (mean 12.5 months); 31 patients (70%) had a second disease relapse, 14 of them with severe disease. The mean time to second relapse was 9.4 months (4.7 months in the group treated with RTX versus 13.7 months in the group treated with CYC/AZA; P < 0.01). Patients who experienced nonsevere relapses received more glucocorticoids than those who maintained remission (6.7 grams versus 3.8 grams; P < 0.01). Conclusion Treatment of nonsevere relapses in AAV with an increase in glucocorticoids is effective in restoring temporary remission in the majority of patients, but recurrent relapses within a relatively short interval remain common. Alternative treatment approaches are needed for this important subset of patients. [ABSTRACT FROM AUTHOR]