Plasma exchange and glucocorticoids to delay death or end-stage renal disease in anti-neutrophil cytoplasm antibody-associated vasculitis: PEXIVAS non-inferiority factorial RCT.

BACKGROUND

Anti-neutrophil cytoplasm antibody-associated vasculitis is a multisystem, autoimmune disease that causes organ failure and death. Physical removal of pathogenic autoantibodies by plasma exchange is recommended for severe presentations, along with high-dose glucocorticoids, but glucocorticoid toxicity contributes to morbidity and mortality. The lack of a robust evidence base to guide the use of plasma exchange and glucocorticoid dosing contributes to variation in practice and suboptimal outcomes.

OBJECTIVES

We aimed to determine the clinical efficacy of plasma exchange in addition to immunosuppressive therapy and glucocorticoids with respect to death and end-stage renal disease in patients with severe anti-neutrophil cytoplasm antibody-associated vasculitis. We also aimed to determine whether or not a reduced-dose glucocorticoid regimen was non-inferior to a standard-dose regimen with respect to death and end-stage renal disease.

DESIGN

This was an international, multicentre, open-label, randomised controlled trial. Patients were randomised in a two-by-two factorial design to receive either adjunctive plasma exchange or no plasma exchange, and either a reduced or a standard glucocorticoid dosing regimen. All patients received immunosuppressive induction therapy with cyclophosphamide or rituximab.

SETTING

Ninety-five hospitals in Europe, North America, Australia/New Zealand and Japan participated.

PARTICIPANTS

Participants were aged ≥ 16 years with a diagnosis of granulomatosis with polyangiitis or microscopic polyangiitis, and either proteinase 3 anti-neutrophil cytoplasm antibody or myeloperoxidase anti-neutrophil cytoplasm antibody positivity, and a glomerular filtration rate of < 50 ml/minute/1.73 m

INTERVENTIONS

Participants received seven sessions of plasma exchange within 14 days or no plasma exchange. Oral glucocorticoids commenced with prednisolone 1 mg/kg/day and were reduced over different lengths of time to 5 mg/kg/day, such that cumulative oral glucocorticoid exposure in the first 6 months was 50% lower in patients allocated to the reduced-dose regimen than in those allocated to the standard-dose regimen. All patients received the same glucocorticoid dosing from 6 to 12 months. Subsequent dosing was at the discretion of the treating physician.

PRIMARY OUTCOME

The primary outcome was a composite of all-cause mortality and end-stage renal disease at a common close-out when the last patient had completed 10 months in the trial.

RESULTS

The study recruited 704 patients from June 2010 to September 2016. Ninety-nine patients died and 138 developed end-stage renal disease, with the primary end point occurring in 209 out of 704 (29.7%) patients: 100 out of 352 (28%) in the plasma exchange group and 109 out of 352 (31%) in the no plasma exchange group (adjusted hazard ratio 0.86, 95% confidence interval 0.65 to 1.13;

CONCLUSIONS

Plasma exchange did not prolong the time to death and/or end-stage renal disease in patients with anti-neutrophil cytoplasm antibody-associated vasculitis with severe renal or pulmonary involvement. A reduced-dose glucocorticoid regimen was non-inferior to a standard-dose regimen and was associated with fewer serious infections.

FUTURE WORK

A meta-analysis examining the effects of plasma exchange on kidney outcomes in anti-neutrophil cytoplasm antibody-associated vasculitis is planned. A health-economic analysis of data collected in this study to examine the impact of both plasma exchange and reduced glucocorticoid dosing is planned to address the utility of plasma exchange for reducing early end-stage renal disease rates. Blood and tissue samples collected in the study will be examined to identify predictors of response to plasma exchange in anti-neutrophil cytoplasm in antibody-associated vasculitis. The benefits associated with reduced glucocorticoid dosing will inform future studies of newer therapies to permit further reduction in glucocorticoid exposure. Data from this study will contribute to updated management recommendations for anti-neutrophil cytoplasm antibody-associated vasculitis.

LIMITATIONS

This study had an open-label design which may have permitted observer bias; however, the nature of the end points, end-stage renal disease and death, would have minimised this risk. Despite being, to our knowledge, the largest ever trial in anti-neutrophil cytoplasm antibody-associated vasculitis, there was an insufficient sample size to assess clinically useful benefits on the separate components of the primary end-point: end-stage renal disease and death. Use of a fixed-dose plasma exchange regimen determined by consensus rather than data-driven dose ranging meant that some patients may have been underdosed, thus reducing the therapeutic impact. In particular, no biomarkers have been identified to help determine dosing in a particular patient, although this is one of the goals of the biomarker plan of this study.

TRIAL REGISTRATION

This trial is registered as ISRCTN07757494, EudraCT 2009-013220-24 and Clinicaltrials.gov NCT00987389.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in

Anti-neutrophil cytoplasm antibody vasculitis is a rare and severe disease in which the patient makes antibodies that damage their blood vessels. It can cause lung damage, kidney failure and early death. Treatment aims to suppress the harmful effects of the antibodies and associated inflammation. In particular: Plasma exchange aims to remove the antibodies from the bloodstream.Steroids aim to reduce the harmful activity of the antibodies. Unfortunately, plasma exchange is expensive and time-consuming, and we do not know if it really works long term to reduce kidney damage or the risk of death. We know steroids work, but they have many severe side effects that are related to higher doses. Again, we do not know if lower doses are equally effective. We conducted a randomised trial, PEXIVAS (Plasma Exchange In VASculitis), to measure the clinical effectiveness of plasma exchange and of reduced steroid doses. Anti-neutrophil cytoplasm antibody vasculitis patients with severe kidney or lung disease were allocated randomly to either plasma exchange or no plasma exchange. The same patients were then randomly allocated to a ‘reduced’ or ‘standard’ steroid dose. All patients received an immunosuppressive drug: cyclophosphamide or rituximab. The primary end point for both trials was the occurrence of either kidney failure or death. A total of 704 patients were recruited between 2010 and 2016, and they were followed up until the end of the trial in July 2017. Ninety-nine patients died and 138 developed kidney failure. Plasma exchange did not reduce the chances of death or kidney failure. There was also no difference between the two steroid dose groups in the number of deaths or patients developing kidney failure. However, there were fewer serious infections in the reduced steroid dose group. These results do not support the routine use of plasma exchange for all patients with severe vasculitis. They do show that the reduced-dose steroid regimen is just as effective as, and safer than, a ‘standard’-dose steroid regimen. These results have the potential to save money and make the treatment of vasculitis patients safer in the future.