The CARI guidelines. Induction and maintenance therapy in ANCA-associated systemic vasculitis

Unravelling the Link between the Gut Microbiome and Autoimmune Kidney Diseases: A Potential New Therapeutic Approach

The gut microbiota and short chain fatty acids (SCFA) have been associated with immune regulation and autoimmune diseases. Autoimmune kidney diseases arise from a loss of tolerance to antigens, often with unclear triggers. In this review, we explore the role of the gut microbiome and how disease, diet, and therapy can alter the gut microbiota consortium. Perturbations in the gut microbiota may systemically induce the translocation of microbiota-derived inflammatory molecules such as liposaccharide (LPS) and other toxins by penetrating the gut epithelial barrier. Once in the blood stream, these pro-inflammatory mediators activate immune cells, which release pro-inflammatory molecules, many of which are antigens in autoimmune diseases. The ratio of gut bacteria Bacteroidetes/Firmicutes is associated with worse outcomes in multiple autoimmune kidney diseases including lupus nephritis, MPO-ANCA vasculitis, and Goodpasture's syndrome. Therapies that enhance SCFA-producing bacteria in the gut have powerful therapeutic potential. Dietary fiber is fermented by gut bacteria which in turn release SCFAs that protect the gut barrier, as well as modulating immune responses towards a tolerogenic anti-inflammatory state. Herein, we describe where the current field of research is and the strategies to harness the gut microbiome as potential therapy.

Interventions for renal vasculitis in adults

BACKGROUND

Renal vasculitis presents as rapidly progressive glomerulonephritis and comprises of a group of conditions characterised by acute kidney injury (AKI), haematuria and proteinuria. Treatment of these conditions involve the use of steroid and non-steroid agents in combination with plasma exchange. Although immunosuppression overall has been very successful in treatment of these conditions, many questions remain unanswered in terms of dose and duration of therapy, the use of plasma exchange and the role of new therapies. This 2019 publication is an update of a review first published in 2008 and updated in 2015.

OBJECTIVES

To evaluate the benefits and harms of any intervention used for the treatment of renal vasculitis in adults.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 21 November 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials investigating any intervention for the treatment of renal vasculitis in adults.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using a random effects model and results expressed as risk ratio (RR) with 95% confidence intervals (CI) for dichotomous outcomes or mean difference (MD) for continuous outcomes.

MAIN RESULTS

Forty studies (3764 patients) were included. Studies conducted earlier tended to have a higher risk of bias due to poor (or poorly reported) study design, broad inclusion criteria, less well developed disease definitions and low patient numbers. Later studies tend to have improved in all areas of quality, aided by the development of large international study groups. Induction therapy: Plasma exchange as adjunctive therapy may reduce the need for dialysis at three (2 studies: RR 0.43, 95% CI 0.23 to 0.78; I2 = 0%) and 12 months (6 studies: RR 0.45, 95% CI 0.29 to 0.72; I2 = 0%) (low certainty evidence). Plasma exchange may make little or no difference to death, serum creatinine (SCr), sustained remission or to serious or the total number of adverse events. Plasma exchange may increase the number of serious infections (5 studies: RR 1.26, 95% CI 1.03 to 1.54; I2 = 0%; low certainty evidence). Remission rates for pulse versus continuous cyclophosphamide (CPA) were equivalent but pulse treatment may increase the risk of relapse (4 studies: RR 1.79, 95% CI 1.11 to 2.87; I2 = 0%) (low certainty evidence) compared with continuous cyclophosphamide. Pulse CPA may make little or no difference to death at final follow-up, or SCr at any time point. More patients required dialysis in the pulse CPA group. Leukopenia was less common with pulse treatment; however, nausea was more common. Rituximab compared to CPA probably makes little or no difference to death, remission, relapse, severe adverse events, serious infections, or severe adverse events. Kidney function and dialysis were not reported. A single study reported no difference in the number of deaths, need for dialysis, or adverse events between mycophenolate mofetil (MMF) and CPA. Remission was reported to improve with MMF however more patients relapsed. A lower dose of steroids was probably as effective as high dose and may be safer, causing fewer infections; kidney function and relapse were not reported. There was little of no difference in death or remission between six and 12 pulses of CPA. There is low certainty evidence that there were less relapses with 12 pulses (2 studies: RR 1.57, 95% CI 0.96 to 2.56; I2 = 0%), but more infections (2 studies: RR 0.79, 95% CI 0.36 to 1.72; I2 = 45%). One study reported severe adverse events were less in patients receiving six compared to 12 pulses of CPA. Kidney function and dialysis were not reported. There is limited evidence from single studies about the effectiveness of intravenous immunoglobulin, avacopan, methotrexate, immunoadsorption, lymphocytapheresis, or etanercept. Maintenance therapy: Azathioprine (AZA) has equivalent efficacy as a maintenance agent to CPA with fewer episodes of leucopenia. MMF resulted in a higher relapse rate when tested against azathioprine in remission maintenance. Rituximab is an effective remission induction and maintenance agent. Oral co-trimoxazole did not reduce relapses in granulomatosis with polyangiitis. There were fewer relapses but more serious adverse events with leflunomide compared to methotrexate. There is limited evidence from single studies about the effectiveness of methotrexate versus CPA or AZA, cyclosporin versus CPA, extended versus standard AZA, and belimumab.

AUTHORS' CONCLUSIONS

Plasma exchange was effective in patients with severe AKI secondary to vasculitis. Pulse cyclophosphamide may result in an increased risk of relapse when compared to continuous oral use but a reduced total dose. Whilst CPA is standard induction treatment, rituximab and MMF were also effective. AZA, methotrexate and leflunomide were effective as maintenance therapy. Further studies are required to more clearly delineate the appropriate place of newer agents within an evidence-based therapeutic strategy.

[Current guidelines on ANCA-associated vasculitides : Common features and differences]

The results of a number of prospective randomized controlled clinical trials have led to changes in established strategies for the treatment of antineutrophil cytoplasmic antibody (ANCA) associated vasculitides (AAV) in recent years. Since 2014, a total of 4 scientific societies and study groups have systematically reviewed the new data and have formulated evidence-based recommendations for the management of AAV based on the analysis. These recommendations contain information on diagnosis, treatment (induction and maintenance), supportive care and monitoring of disease activity and resulting damage. This review compares the recently published recommendations of the German Society of Rheumatology (Deutschen Gesellschaft für Rheumatologie, DGRh), the European League Against Rheumatism (EULAR)/European Renal Association (ERA), the British Society of Rheumatology (BSR) and the Canadian Vasculitis Research Network (CanVasc). The comparative analysis reveals a high level of agreement on numerous topics but also shows some minor and even a few major differences in the respective recommended approach to diagnosis and treatment of AAV. Divergent recommendations predominantly exist in areas with little scientific evidence from clinical studies. Furthermore, some differences result from different interpretation of existing data or are influenced by characteristic features of the respective national healthcare system.

Clinical practice variation and need for pediatric-specific treatment guidelines among rheumatologists caring for children with ANCA-associated vasculitis: an international clinician survey

BACKGROUND

Because pediatric antineutrophil cytoplasmic antibody-associated vasculitis is rare, management generally relies on adult data. We assessed treatment practices, uptake of existing clinical assessment tools, and interest in pediatric treatment protocols among rheumatologists caring for children with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

METHODS

A needs-assessment survey developed by an international working group of pediatric rheumatologists and two nephrologists was circulated internationally. Data were summarized with descriptive statistics. Pearson's chi-square tests were used in inferential univariate analyses.

RESULTS

The 209 respondents from 36 countries had collectively seen ~1600 children with GPA/MPA; 144 had seen more than two in the preceding 5 years. Standardized and validated clinical assessment tools to score disease severity, activity, and damage were used by 59, 63, and 36%, respectively; barriers to use included lack of knowledge and limited perceived utility. Therapy varied significantly: use of rituximab rather than cyclophosphamide was more common among respondents from the USA (OR = 2.7 [1.3-5.5], p = 0.0190, n = 139), those with >5 years of independent practice experience (OR = 3.8 [1.3-12.5], p = 0.0279, n = 137), and those who had seen >10 children with GPA/MPA in their careers (OR = 4.39 [2.1-9.1], p = 0.0011, n = 133). Respondents who had treated >10 patients were also more likely to continue maintenance therapy for at least 24 months (OR = 3.0 [1.4-6.4], p = 0.0161, n = 127). Ninety six percent of respondents believed in a need for pediatric-specific treatment guidelines; 46% supported adaptation of adult guidelines while 69% favoured guidelines providing a limited range of treatment options to allow comparison of effectiveness through a registry.

CONCLUSIONS

These data provide a rationale for developing pediatric-specific consensus treatment guidelines for GPA/MPA. While pediatric rheumatologist uptake of existing clinical tools has been limited, guideline uptake may be enhanced if outcomes of consensus-derived treatment options are evaluated within the framework of an international registry.

CanVasc recommendations for the management of antineutrophil cytoplasm antibody (ANCA)-associated vasculitides - Executive summary

The Canadian Vasculitis research network (CanVasc) is composed of physicians from different medical specialties, including rheumatology and nephrology and researchers with expertise in vasculitis. One of its aims was to develop recommendations for the diagnosis and management of antineutrophil cytoplasm antibody (ANCA)-associated vasculitides in Canada. This executive summary features the 19 recommendations and 17 statements addressing general AAV diagnosis and management, developed by CanVasc group based on a synthesis of existing international guidelines, other published supporting evidence and expert consensus considering the Canadian healthcare context.

CanVasc Recommendations for the Management of Antineutrophil Cytoplasm Antibody-associated Vasculitides

Objective.

The Canadian Vasculitis research network (CanVasc) is composed of physicians from different medical specialties and researchers with expertise in vasculitis. One of its aims is to develop recommendations for the diagnosis and management of antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) in Canada.

Methods.

Diagnostic and therapeutic questions were developed based on the results of a national needs assessment survey. A systematic review of existing non-Canadian recommendations and guidelines for the diagnosis and management of AAV and studies of AAV published after the 2009 European League Against Rheumatism/European Vasculitis Society recommendations (publication date: January 2009) until November 2014 was performed in the Medline database, Cochrane library, and main vasculitis conference proceedings. Quality of supporting evidence for each therapeutic recommendation was graded. The full working group as well as additional reviewers, including patients, reviewed the developed therapeutic recommendations and nontherapeutic statements using a modified 2-step Delphi technique and through discussion to reach consensus.

Results.

Nineteen recommendations and 17 statements addressing general AAV diagnosis and management were developed, as well as appendices for practical use, for rheumatologists, nephrologists, respirologists, general internists, and all other healthcare professionals more occasionally involved in the management of patients with AAV in community and academic practice settings.

Conclusion.

These recommendations were developed based on a synthesis of existing international guidelines, other published supporting evidence, and expert consensus considering the Canadian healthcare context, with the intention of promoting best practices and improving healthcare delivery for patients with AAV.

Interventions for renal vasculitis in adults

BACKGROUND

Renal vasculitis presents as rapidly progressive glomerulonephritis which comprises of a group of conditions characterised by acute kidney injury (AKI), haematuria and proteinuria. Treatment of these conditions comprises steroid and non-steroid agents in combination with plasma exchange. Although immunosuppression overall has been very successful in treatment of these conditions, many questions remain unanswered in terms of dose and duration of therapy, the use of plasma exchange and the role of new therapies. This an update of a review first published in 2008.

OBJECTIVES

To evaluate the benefits and harms of any intervention used for the treatment of renal vasculitis in adults.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register up to 27 July 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials investigating any intervention for the treatment of renal vasculitis in adults.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using a random effects model and results expressed as risk ratio (RR) with 95% confidence intervals (CI) for dichotomous outcomes or mean difference (MD) for continuous outcomes.

MAIN RESULTS

Thirty one studies (2217 patients) were included. Studies conducted earlier tended to have a higher risk of bias due to poor (or poorly reported) study design, broad inclusion criteria, less well developed disease definitions and low patient numbers. Later studies tend to have improved in all areas of quality, aided by the development of large transnational study groups.Plasma exchange as adjunctive therapy significantly reduces the risk of end-stage kidney disease at three months (2 studies: RR 0.43, 95% CI 0.23 to 0.78) and 12 months (6 studies: RR 0.45, 95% CI 0.29 to 0.72). Four studies (300 patients) compared the use of pulse and continuous administration of cyclophosphamide. Remission rates were equivalent but pulse treatment causes an increased risk of relapse (4 studies: RR 1.79, 95% CI 1.11 to 2.87) compared with continuous cyclophosphamide. Azathioprine has equivalent efficacy as a maintenance agent to cyclophosphamide with fewer episodes of leucopenia. Mycophenolate mofetil may be equivalent to cyclophosphamide as an induction agent but resulted in a higher relapse rate when tested against azathioprine in remission maintenance. Rituximab is an effective remission induction agent. Methotrexate or leflunomide are potential choices in remission maintenance therapy. Oral co-trimoxazole did not reduce relapses significantly in granulomatosis with polyangiitis.

AUTHORS' CONCLUSIONS

Plasma exchange was effective in patients with severe AKI secondary to vasculitis. Pulse cyclophosphamide results in an increased risk of relapse when compared to continuous oral use but a reduced total dose. Whilst cyclophosphamide is standard induction treatment, rituximab and mycophenolate mofetil were also effective. Azathioprine, methotrexate and leflunomide were effective as maintenance therapy. Further studies are required to more clearly delineate the appropriate place of newer agents within an evidence-based therapeutic strategy.

Long-term follow-up of cyclophosphamide compared with azathioprine for initial maintenance therapy in ANCA-associated vasculitis

BACKGROUND AND OBJECTIVES

Treatment with azathioprine within 3 months of remission induction with cyclophosphamide is a common treatment strategy for patients with ANCA-associated vasculitis. This study comprised patients undergoing long-term follow-up who were randomly allocated to azathioprine after 3-6 months or after 12 months of cyclophosphamide treatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients from 39 European centers between 1995 and 1997 with a new diagnosis of ANCA-associated vasculitis that involved the kidneys or another vital organ were eligible. At the time of diagnosis, participants were randomly allocated to convert to azathioprine after 3-6 months (the azathioprine group) or after 12 months of cyclophosphamide (the cyclophosphamide group). Patients who did not achieve a remission within 6 months were excluded. This study assessed relapses, ESRD, and death during long-term follow-up.

RESULTS

Patients were allocated to the azathioprine group (n=71) and the cyclophosphamide group (n=73). Of these patients, 63 (43.8%) developed a relapse, 35 (24.3%) developed a renal relapse, 13 (9.0%) developed ESRD, and 21 (14.6%) died. Although there were worse outcomes in the azathioprine group, none were statistically significant. The subdistribution hazard ratio [sHR] for relapse was 1.63 (95% confidence interval [95% CI], 0.99 to 2.71), the composite of relapse or death hazard ratio [HR] was 1.59 (95% CI, 1.00 to 2.54), the ESRD sHR was 1.71 (95% CI, 0.56 to 5.19), and the death HR was 0.75 (95% CI, 0.32 to 1.79).

CONCLUSIONS

It remains uncertain whether converting to azathioprine after 3-6 months of induction cyclophosphamide therapy is as effective as converting after 12 months. Outcomes are still poor for this group of patients and further research is required to determine the optimal timing of maintenance therapy.

Long-term follow-up of patients with severe ANCA-associated vasculitis comparing plasma exchange to intravenous methylprednisolone treatment is unclear

Patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV) requiring dialysis at diagnosis are at risk for developing end-stage renal disease (ESRD) or dying. Short-term results of a trial comparing plasma exchange (PLEX) to intravenous methylprednisolone (IV MeP) suggested PLEX improved renal recovery. Here we conducted long-term follow-up to see if this trend persisted. A total of 137 patients with newly diagnosed AAV and a serum creatinine over 500 μmol/l or requiring dialysis were randomized such that 69 received PLEX and 68 received IV MeP in addition to cyclophosphamide and oral glucocorticoids. The patients were followed for a median of 3.95 years. In each group there were 35 deaths, while 23 PLEX and 33 IV MeP patients developed ESRD. The hazard ratio for PLEX compared to IV MeP for the primary composite outcome of death or ESRD was 0.81 (95% confidence interval 0.53-1.23). The hazard ratio for all-cause death was 1.08 with a subhazard ratio for ESRD of 0.64 (95% confidence interval 0.40-1.05). Thus, although short-term results with PLEX are encouraging, the long-term benefits remain unclear. Further research is required to determine the role of PLEX in AAV. Given the poor outcomes of patients with severe AAV, improved treatment is urgently needed.

Plasma exchange for renal vasculitis and idiopathic rapidly progressive glomerulonephritis: a meta-analysis

BACKGROUND

Plasma exchange may be effective adjunctive treatment for renal vasculitis. We performed a systematic review and meta-analysis of randomized controlled trials of plasma exchange for renal vasculitis.

STUDY DESIGN

Systematic review and meta-analysis of articles identified from electronic databases, bibliographies, and studies identified by experts. Data were abstracted in parallel by 2 reviewers.

SETTING & POPULATION

Adults with idiopathic renal vasculitis or rapidly progressive glomerulonephritis.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials that compared standard care with standard care plus adjuvant plasma exchange in adult patients with either renal vasculitis or idiopathic rapidly progressive glomerulonephritis.

INTERVENTION

Adjuvant plasma exchange.

OUTCOME

Composite of end-stage renal disease or death.

RESULTS

We identified 9 trials including 387 patients. In a fixed-effects model, the pooled RR for end-stage renal disease or death was 0.80 for patients treated with adjunctive plasma exchange compared with standard care alone (95% CI, 0.65-0.99; P = 0.04). No significant heterogeneity was detected (P = 0.5; I(2) = 0%). The effect of plasma exchange did not differ significantly across the range of baseline serum creatinine values (P = 0.7) or number of plasma exchange treatments (P = 0.8). The RR for end-stage renal disease was 0.64 (95% CI, 0.47-0.88; P = 0.006), whereas the RR for death alone was 1.01 (95% CI, 0.71-1.4; P = 0.9).

LIMITATIONS

Although the primary result was statistically significant, there is insufficient statistical information to reliably determine whether plasma exchange decreases the composite of end-stage renal disease or death.

CONCLUSIONS

Plasma exchange may decrease the composite end point of end-stage renal disease or death in patients with renal vasculitis. Additional trials are required given the limited data available.

Interventions for renal vasculitis in adults. A systematic review

Background

Renal vasculitis presents as rapidly progressive glomerulonephritis and comprises of a group of conditions characterised by acute kidney failure, haematuria and proteinuria. Treatment of these conditions involves the use of steroid and non-steroid agents with or without adjunctive plasma exchange. Although immunosuppression has been successful, many questions remain unanswered in terms of dose and duration of therapy, the use of plasma exchange and the role of new therapies. This systematic review was conducted to determine the benefits and harms of any intervention for the treatment of renal vasculitis in adults.

Methods

We searched the Cochrane Central Register of Controlled Trials, the Cochrane Renal Group Specialised Register, MEDLINE and EMBASE to June 2009. Randomised controlled trials investigating any intervention for the treatment of adults were included. Two authors independently assessed study quality and extracted data. Statistical analyses were performed using a random effects model and results expressed as risk ratio with 95% confidence intervals for dichotomous outcomes or mean difference for continuous outcomes.

Results

Twenty two studies (1674 patients) were included. Plasma exchange as adjunctive therapy significantly reduces the risk of end-stage kidney disease at 12 months (five studies: RR 0.47, CI 0.30 to 0.75). Four studies compared the use of pulse and continuous administration of cyclophosphamide. Remission rates were equivalent but pulse treatment causes an increased risk of relapse (4 studies: RR 1.79, CI 1.11 to 2.87) compared with continuous cyclophosphamide. Azathioprine has equivalent efficacy as a maintenance agent to cyclophosphamide with fewer episodes of leukopenia. Mycophenolate mofetil may be equivalent to cyclophosphamide as an induction agent but resulted in a higher relapse rate when tested against Azathioprine in remission maintenance. Rituximab is an effective remission induction agent. Methotrexate or Leflunomide are potential choices in remission maintenance therapy. Oral co-trimoxazole did not reduce relapses significantly in Wegener's granulomatosis.

Conclusions

Plasma exchange is effective in patients with severe ARF secondary to vasculitis. Pulse cyclophosphamide results in an increased risk of relapse when compared to continuous oral use but a reduced total dose. Whilst cyclophosphamide is standard induction treatment, rituximab and mycophenolate mofetil are also effective. Azathioprine, methotrexate and leflunomide are effective as maintenance therapy. Further studies are required to more clearly delineate the appropriate place of newer agents within an evidence-based therapeutic strategy.