Clark, William F.

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 m2 or diffuse alveolar haemorrhage attributable to active anti-neutrophil cytoplasm antibody-associated vasculitis. 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; p = 0.3). In the per-protocol analysis for the non-inferiority glucocorticoid comparison, the primary end point occurred in 92 out of 330 (28%) patients in the reduced-dose group and 83 out of 325 (26%) patients in the standard-dose group (partial-adjusted risk difference 0.023, 95% confidence interval 0.034 to 0.08; p = 0.5), thus meeting our non-inferiority hypothesis. Serious infections in the first year occurred in 96 out of 353 (27%) patients in the reduced-dose group and in 116 out of 351 (33%) patients in the standard-dose group. The rate of serious infections at 1 year was lower in the reduced-dose group than in the standard-dose group (incidence rate ratio 0.69, 95% confidence interval 0.52 to 0.93; p = 0.016). 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 Health Technology Assessment; Vol. 26, No. 38. See the NIHR Journals Library website for further project information.

Abstract Background : Many idiopathic thrombotic thrombocytopenia purpura (TTP) patients have severe deficiency of ADAMTS13, an enzyme that cleaves ultralarge von Willebrand multimers. We recently reported that thienopyridine-associated TTP is characterized by an immunologic pathway with severe ADAMTS13 deficiency and a non-immunologic pathway with higher ADAMTS13 activity levels. We now compare findings for idiopathic and thienopyridine-associated TTP patients. Methods : Clinical findings and laboratory findings were evaluated for 51 idiopathic and 39 thienopyridine-associated TTP. Results: Clinical findings were similar between idiopathic and thienopyridine-associated TTP for both severe ADAMTS13 deficient and non-deficient patients. Differences were noted in gender and age, relapse rates, and survival. Conclusion : Among TTP patients with ADAMTS13 deficiency, relapses are frequent in idiopathic TTP patients and Rituximab may be useful, while for thienopyridine-associated TTP patients spontaneous relapse are rare as long as no re-exposure occurs. Among ADAMTS13 non-deficient patients, survival is high following therapeutic plasma exchange (TPE) for idiopathic patients but not for thienopyridine-associated TTP patients. Despite similarities, idiopathic and thienopyridine associated TTP probably have different initiating factors. ADAMTS13 activity and clinical characteristics in idiopathic and thienopyridine-associated TTP Idiopathic severe ADAMTS13 deficiency (n=29) †Thienopyridine severe ADAMTS13 deficiency (n=26) Idiopathic non-severe ADAMTS13 deficiency (n=22) †Thienopyridine non-severe ADAMTS13 deficiency (n=13) *p&lt;0.05 for comparison of severe ADAMTS13 deficiency versus non-severe ADAMTS13 deficiency. †Thienopyridine-associated TTP clinical and presenting neutralizing autoantibody data was summarized from the Journal of the American College of Cardiology publication by Bennett et al. in 2007. ‡Thienopyridine-associated TTP remission autoantibody data was summarized Tsai et al, 2002, Bennett et al, 2000, and Orimo et al, 2002, and included 3 patients. §Data from average of ADAMTS13 deficient and non-deficient cohorts. Mean Age 41 67 47 60 Sex (% female) 79% 54% 86% 39% Platelet count/mm3 (mean)* 18,978 9,269 51,409 35,000 Platelet count &lt;20,000/mm3* 69% 96% 23% 38% Hemoglobin (mg/dl; mean) 8.5 8.3 9.0 8.4 Creatinine (mg/dl; mean)* 1.5 2.2 3.2 3.0 Creatinine &gt;2.5 mg/dl* 11% 27% 48% 46% 30-day survival 96% 85% 90% 62% Long-term relapse* 42% 8% 0% 0% Neutralizing autoantibodies to ADAMTS13 (prior to TPE) § 79% 100% 27% 0% Neutralizing autoantibodies to ADAMTS 13 (measured at remission) § 55% 33%‡ 33% 0%

Abstract Abstract 2203 Background: Thrombotic thrombocytopenic purpura (TTP) is frequently characterized by severe ADAMTS13 deficiency, the cause of which is unknown. An important exception is ticlopidine-associated TTP (tc-TTP), the most common drug-induced TTP syndrome. In 1998, a possible association of TTP with ticlopidine was reported. In 1999, two additional series reported this association. In 2000, a fourth study reported severe A DAMTS13 deficiency among six of seven tc-TTP persons- suggesting a causal pathway. All of these reports were from the United States. Recently, we reported characteristics of 186 acquired idiopathic (ai)- TTP patients in Japan with severe ADAMTS13 deficiency, noting that clinical and laboratory findings for ai-TTP patients in Japan differed from those for cohorts of ai-TTP patients in Europe and North America- raising concern that TTP findings vary by region of the world. (PLOS One 2011) We now on report clinical and laboratory characteristics of a cohort of TTP patients from Japan with tc-TTP, and compare these findings to three cohorts of tc-TTP in the United States and one cohort of ai-TTP patients from Japan. Methods: We queried a database of thrombotic microangiopathy patients identified from a national TTP referral laboratory in Japan of cases identified between 1998 and 2008. Severe ADAMTS13 deficiency was characterized by activity levels < 5%. All tc-TTP patients and 186 of 911 ai-TTP patients in the database had severe ADAMTS13 deficiency and first onset of TTP. Comparisons were made to tc-TTP patients reported previously from the United States. Results: Characteristics of ai- TTP with severe ADAMTS13 deficiency in Japan and tc-TTP in Japan and US Conclusions: These data from Japan validate insights about tc-TTP initially proposed in 1998, 1999, and 2000 in the United States. Ticlopidine is a likely cause of TTP, the mechanism is via a cross-reactive antibody to ADAMTS13:AC resulting in formation of an ADAMTS13:INH, and therapeutic plasma exchange is necessary for treatment. Disclosures: Ortel: Eisai: Research Funding; Glaxo SmithKline: Research Funding; Pfizer: Research Funding; Instrumentation Laboratory, Inc: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy. Fujimura:Baxter BioScience: Membership on an entity's Board of Directors or advisory committees; Alexion Pharma: Membership on an entity's Board of Directors or advisory committees.