Jacques Pourrat

Predictive Features of Severe Acquired ADAMTS13 Deficiency in Idiopathic Thrombotic Microangiopathies: The French TMA Reference Center Experience

Severe ADAMTS13 deficiency occurs in 13% to 75% of thrombotic microangiopathies (TMA). In this context, the early identification of a severe, antibody-mediated, ADAMTS13 deficiency may allow to start targeted therapies such as B-lymphocytes-depleting monoclonal antibodies. To date, assays exploring ADAMTS13 activity require skill and are limited to only some specialized reference laboratories, given the very low incidence of the disease. To identify clinical features which may allow to predict rapidly an acquired ADAMTS13 deficiency, we performed a cross-sectional analysis of our national registry from 2000 to 2007. The clinical presentation of 160 patients with TMA and acquired ADAMTS13 deficiency was compared with that of 54 patients with detectable ADAMTS13 activity. ADAMTS13 deficiency was associated with more relapses during treatment and with a good renal prognosis. Patients with acquired ADAMTS13 deficiency had platelet count <30×109/L (adjusted odds ratio [OR] 9.1, 95% confidence interval [CI] 3.4–24.2, P<.001), serum creatinine level ≤200 µmol/L (OR 23.4, 95% CI 8.8–62.5, P<.001), and detectable antinuclear antibodies (OR 2.8, 95% CI 1.0–8.0, P<.05). When at least 1 criteria was met, patients with a severe acquired ADAMTS13 deficiency were identified with positive predictive value of 85%, negative predictive value of 93.3%, sensitivity of 98.8%, and specificity of 48.1%. Our criteria should be useful to identify rapidly newly diagnosed patients with an acquired ADAMTS13 deficiency to better tailor treatment for different pathophysiological groups.

Efficacy and safety of first-line rituximab in severe, acquired thrombotic thrombocytopenic purpura with a suboptimal response to plasma exchange. Experience of the French Thrombotic Microangiopathies Reference Center.

Objective:To assess the efficacy and safety of rituximab in adults responding poorly to standard treatment for severe autoimmune thrombotic thrombocytopenic purpura. Design:Open-label prospective study. Outcomes in the survivors were compared to those of 53 historical survivors who were given therapeutic plasma exchange alone or with vincristine. Setting:Hospitals belonging to the Reference Network for Thrombotic Microangiopathies in France. Patients:Twenty-two adults with either no response or a disease exacerbation when treated with intensive therapeutic plasma exchange. Intervention:Add-on rituximab therapy, four infusions over 15 days. Measurements and Main Results:One patient died despite two rituximab infusions. In the rituximab-treated patients, the time to a durable remission was significantly shortened (p = .03), although the plasma volume required to achieve a durable remission was not significantly different compared to the controls. Platelet count recovery occurred within 35 days in all 21 survivors, compared to only 78% of the historical controls (p < .02). Of the rituximab-treated patients, none had a relapse within the first year but three relapsed later on. In patients treated with rituximab, a rapid and profound peripheral B-cell depletion was produced, lasting for 9 months and correlating with higher a disintegrin and metalloproteinase with thrombospondin-13 activity and lower anti-a disintegrin and metalloproteinase with thrombospondin-13 antibody titers. These differences were no longer significant after 12 months. No severe side effects occurred. Conclusions:Adults with severe thrombocytopenic purpura who responded poorly to therapeutic plasma exchange and who were treated with rituximab had shorter overall treatment duration and reduced 1-yr relapses than historical controls.

Scleroderma renal crisis: a retrospective multicentre study on 91 patients and 427 controls

OBJECTIVE Scleroderma renal crisis (SRC) is a severe manifestation of SSc, whose prognosis remains severe, despite treatment with angiotensin-converting-enzyme inhibitor and dialysis. This study was undertaken to describe SRC characteristics, prognosis and outcome, and evaluate the responsibility of CSs in its occurrence. METHODS Analysis concerned 91 SSc patients with SRC who were compared with 427 non-SRC-SSc patients taken as controls. RESULTS Among the 91 SRC patients, 71 (78.0%) had high blood pressure, 53 (58.2%) hypertensive encephalopathy and 51 (56.0%) thrombotic microangiopathy; 64 (70.3%) had received CSs before or concomitantly with SRC vs 156 (36.5%) non-SRC-SSc patients (P < 0.001). Treated SRC patients also received more prednisone 29.3 (28.4) vs 3.6 (9.9) mg than controls (P < 0.001). SRC clinical outcomes were poor: 49 (53.8%) patients required dialysis, which was definitive for 38. Thirty-seven (40.7%) SRC patients died vs 10.8% of the controls (P < 0.001). Death was most frequent among dialysed patients who never recovered renal function (22 vs 2) and 13 never-dialysed SRC patients died. CONCLUSIONS Although SRC prognosis has improved markedly, SRC remains a severe manifestation of SSc, despite treatment with angiotensin-converting enzyme inhibitor and dialysis. CSs contributed significantly to SRC occurrence.

Hydroxychloroquine in systemic lupus erythematosus: results of a French multicentre controlled trial (PLUS Study).

Introduction Hydroxychloroquine (HCQ) is an important medication for treating systemic lupus erythematosus (SLE). Its blood concentration ([HCQ]) varies widely between patients and is a marker and predictor of SLE flares. This prospective randomised, double-blind, placebo-controlled, multicentre study sought to compare standard and adjusted HCQ dosing schedules that target [HCQ] ≥1000 ng/ml to reduce SLE flares. Patients and methods [HCQ] was measured in 573 patients with SLE (stable disease and SELENA-SLEDAI≤12) treated with HCQ for at least 6 months. Patients with [HCQ] from 100 to 750 ng/ml were randomised to one of two treatment groups: no daily dose change (group 1) or increased HCQ dose to achieve the target [HCQ] (group 2). The primary end point was the number of patients with flares during 7 months of follow-up. Results Overall, mean [HCQ] was 918±451 ng/ml. Active SLE was less prevalent in patients with higher [HCQ]. A total of 171 patients were randomised and followed for 7 months. SLE flare rates were similar in the two groups (25% in group 1 vs 27.6% in group 2; p=0.7), but a significant spontaneous increase in [HCQ] in both groups between inclusion and randomisation strongly suggested improved treatment adherence. Patients at the therapeutic target throughout follow-up tended to have fewer flares than those with low [HCQ] (20.5% vs 35.1%, p=0.12). Conclusions Although low [HCQ] is associated with higher SLE activity, adapting the HCQ dose did not reduce SLE flares over a 7-month follow-up. ClinicalTrials.gov NCT00413361

Acute Renal Infarction: A Case Series

BACKGROUND AND OBJECTIVES Renal infarction is an arterial vascular event that may cause irreversible damage to kidney tissues. This study describes the clinical characteristics of patients with renal infarction according to underlying mechanism of vascular injury. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study retrospectively identified 94 patients with renal infarction diagnosed between 1989 and 2011 with the aim of highlighting potential correlations between demographic, clinical, and biologic characteristics and the etiology of renal infarction. Four groups were identified: renal infarction of cardiac origin (cardiac group, n=23), renal infarction associated with renal artery injury (renal injury group, n=29), renal infarction associated with hypercoagulability disorders (hypercoagulable group, n=15), and apparently idiopathic renal infarction (idiopathic group, n=27). RESULTS Clinical symptoms included abdominal and/or flank pain in 96.8% of cases; 46 patients had uncontrolled hypertension at diagnosis. Laboratory findings included increase of lactate dehydrogenase level (90.5%), increase in C-reactive protein level (77.6%), and renal impairment (40.4%). Compared with renal injury group patients, this study found that cardiac group patients were older (relative risk for 1 year increase=1.21, P=0.001) and displayed a lower diastolic BP (relative risk per 1 mmHg=0.94, P=0.05). Patients in the hypercoagulable group had a significantly lower diastolic BP (relative risk=0.86, P=0.005). Patients in the idiopathic group were older (relative risk=1.13, P=0.01) and less frequently men (relative risk=0.11, P=0.02). Seven patients required hemodialysis at the first evaluation, and zero patients died during the first 30 days. CONCLUSIONS This study suggests that the clinical and biologic characteristics of patients can provide valuable information about the causal mechanism involved in renal infarction occurrence.

Treatment of Hepatorenal Syndrome as Defined by the International Ascites Club by Albumin and Furosemide Infusion According to the Central Venous Pressure: A Prospective Pilot Study

OBJECTIVE:Hepatorenal syndrome (HRS) is a functional renal failure that occurs late during cirrhosis. The prognosis is extremely poor with a mean survival of 1.7 wks from the time of diagnosis. The aim of the present study was to examine the effects of albumin and furosemide administration tailored to central venous pressure (CVP) on renal function and clinical outcome.METHODS:We treated 20 consecutive patients with HRS. Albumin was given to increase and/or maintain CVP above 3 cm H2O. If diuresis remained below 50 mL/h despite effective volume expansion, furosemide was administrated. Patients were considered responders and treatment was discontinued when creatinine clearance rose above 40 mL/min or serum creatinine fell under 132 μmol/L.RESULTS:The need for albumin varied from patient to patient (extremes 40–600 g) and in the same patient from day to day. All but one needed furosemide. Eleven patients (55%) responded to treatment. In this population, diuresis, serum creatinine, and creatinine clearance were all significantly improved. Creatinine clearance at baseline was predictive of treatment efficacy. Survival increased in these patients compared to nonresponders defined as patients with no improvement in renal function (259 days ± 113 compared to 14 days ± 3, p < 0.0005). Response to treatment and the type of HRS were the only variables with an independent prognostic value.CONCLUSION:This study shows that HRS as defined by the International Ascites Club can be treated by albumin administration alone or with furosemide given according to the patients specific need using CVP.

Development and validation of a predictive model for death in acquired severe ADAMTS13 deficiency-associated idiopathic thrombotic thrombocytopenic purpura: the French TMA Reference Center experience

Background Acquired thrombotic thrombocytopenic purpura is still associated with a 10–20% death rate. It has still not been possible to clearly identify early prognostic factors of death. This study involved thrombotic thrombocytopenic purpura patients with acquired severe (<10% of normal activity) ADAMTS13 deficiency and aimed to identify prognostic factors associated with 30-day death. Design and Methods The study involved a prospective cohort of patients and was carried out between October 2000 and August 2010. A validation cohort of patients was set up from September 2010 to August 2011. Altogether, 281 (analysis cohort) and 66 (validation cohort) consecutive adult thrombotic thrombocytopenic purpura patients with acquired severe ADAMTS13 deficiency were enrolled. The study evaluated 30-day mortality after treatment initiation according to characteristics at inclusion. Results Non-survivors (11%) were older (P=10−6) and more frequently presented arterial hypertension (P=5.10−4) and ischemic heart disease (P=0.013). Prognosis was increasingly poor with age (P=0.004). On presentation, cerebral manifestations were more frequent in non-survivors (P=0.018) and serum creatinine level was higher (P=0.008). The most significant independent variables determining death were age, severe cerebral involvement and LDH level 10 N or over. A 3-level risk score for early death was defined and confirmed in the validation cohort using these variables, with higher values corresponding to increased risk of early death. Conclusions A risk score for early death was defined in patients with thrombotic thrombocytopenic purpura and validated on an independent cohort. This score should help to stratify early treatment and identify patients with a worse prognosis.

Splenectomy and/or cyclophosphamide as salvage therapies in thrombotic thrombocytopenic purpura: the French TMA Reference Center experience

BACKGROUND: The objective was to assess the efficacy and safety of splenectomy and cyclophosphamide as salvage therapies in severe thrombotic thrombocytopenic purpura (TTP).

Population pharmacokinetics of rituximab with or without plasmapheresis in kidney patients with antibody-mediated disease

AIMS Both rituximab and plasmapheresis can be associated in the treatment of immune-mediated kidney diseases. The real impact of plasmapheresis on rituximab pharmacokinetics is unknown. The aim of this study was to compare rituximab pharmacokinetics between patients requiring plasmapheresis and others without plasmapheresis. METHODS The study included 20 patients receiving one or several infusions of rituximab. In 10 patients, plasmapheresis sessions were also performed (between two and six sessions per patient). Rituximab concentrations were measured in blood samples in all patients and in discarded plasma obtained by plasmapheresis using an enzyme-linked immunosorbent assay method. Data were analysed according to a population pharmacokinetic approach. RESULTS The mean percentage of rituximab removed during the first plasmapheresis session ranged between 47 and 54% when plasmapheresis was performed between 24 and 72 h after rituximab infusion. Rituximab pharmacokinetics was adequately described by a two-compartment model with first-order elimination. Plasmapheresis had a significant impact on rituximab pharmacokinetics, with an increase of rituximab clearance by a factor of 261 (95% confidence interval 146-376), i.e. from 6.64 to 1733 ml h(-1) . Plasmapheresis performed 24 h after rituximab infusion decreased the rituximab area under the curve by 26%. CONCLUSIONS Plasmapheresis removed an important amount of rituximab when performed less than 3 days after infusion. The removal of rituximab led to a significant decrease of the area under the curve. This pharmacokinetic observation should be taken into account for rituximab dosing, e.g. an additional third rituximab infusion may be recommended when three plasmapheresis sessions are performed after the first rituximab infusion.

Life-threatening drug-associated hyperkalemia: a retrospective study from laboratory signals

Life‐threatening hyperkalemia may be induced by drugs and preventable in at‐risk patients. This study was designed to describe cases of ‘serious’ drug‐associated hyperkalemia.