Koichi Kamei

Rituximab for childhood-onset, complicated, frequently relapsing nephrotic syndrome or steroid-dependent nephrotic syndrome: a multicentre, double-blind, randomised, placebo-controlled trial

BACKGROUND Rituximab could be an effective treatment for childhood-onset, complicated, frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome (SDNS). We investigated the efficacy and safety of rituximab in patients with high disease activity. METHODS We did a multicentre, double-blind, randomised, placebo-controlled trial at nine centres in Japan. We screened patients aged 2 years or older experiencing a relapse of FRNS or SDNS, which had originally been diagnosed as nephrotic syndrome when aged 1-18 years. Patients with complicated FRNS or SDNS who met all other criteria were eligible for inclusion after remission of the relapse at screening. We used a computer-generated sequence to randomly assign patients (1:1) to receive rituximab (375 mg/m(2)) or placebo once weekly for 4 weeks, with age, institution, treatment history, and the intervals between the previous three relapses as adjustment factors. Patients, guardians, caregivers, physicians, and individuals assessing outcomes were masked to assignments. All patients received standard steroid treatment for the relapse at screening and stopped taking immunosuppressive agents by 169 days after randomisation. Patients were followed up for 1 year. The primary endpoint was the relapse-free period. Safety endpoints were frequency and severity of adverse events. Patients who received their assigned intervention were included in analyses. This trial is registered with the University Hospital Medical Information Network clinical trials registry, number UMIN000001405. FINDINGS Patients were centrally registered between Nov 13, 2008, and May 19, 2010. Of 52 patients who underwent randomisation, 48 received the assigned intervention (24 were given rituximab and 24 placebo). The median relapse-free period was significantly longer in the rituximab group (267 days, 95% CI 223-374) than in the placebo group (101 days, 70-155; hazard ratio: 0·27, 0·14-0·53; p<0·0001). Ten patients (42%) in the rituximab group and six (25%) in the placebo group had at least one serious adverse event (p=0·36). INTERPRETATION Rituximab is an effective and safe treatment for childhood-onset, complicated FRNS and SDNS. FUNDING Japanese Ministry of Health, Labour and Welfare.

Rituximab in refractory nephrotic syndrome

The aim of this study was to establish the efficacy and safety of rituximab in refractory nephrotic syndrome (NS). Members of the International Paediatric Nephrology Association were asked to retrospectively fill in a questionnaire with details on the use of rituximab in their centres. We divided the data into three groups: group 1, patients with steroid-dependent and frequently relapsing NS; group 2, with steroid-resistant NS; group 3, with post-transplant recurrence of NS. Seventy questionnaires from 25 centres described the outcome of 28, 27 and 15 patients in groups 1, 2 and 3, respectively. Of these, 82% of patients in group 1, 44% of patients in group 2 and 60% of patients in group 3 had a good initial response. Side effects were observed in 27% of the patients, and these were mostly acute reactions. We present a large multicentre series of children with refractory NS. Children in group 1 showed the best response. The good initial response in group 3 can be biased by the accompanying treatments that were administered at the same time as rituximab. Controlled prospective trials are required to establish the value of rituximab in idiopathic NS.

Survey of rituximab treatment for childhood-onset refractory nephrotic syndrome

BackgroundRituximab (RTX) is a promising option for treating childhood-onset steroid-dependent (SDNS), frequently relapsing (FRNS), and steroid-resistant (SRNS) nephrotic syndrome.MethodsWe retrospectively surveyed RTX treatment for these conditions to evaluate its indications, efficacy and adverse events. Questionnaires were sent to 141 hospitals in Japan.ResultsSeventy-four patients (52 SDNS; 3 FRNS; 19 SRNS) were treated with RTX because of resistance to various immunosuppressive agents. Most patients received a single administration of RTX (85%). Forty-one of 53 SDNS/FRNS (77%) and 5 of 17 SRNS (29%) patients successfully discontinued prednisolone (16 SDNS/FRNS and 6 SRNS achieved their first discontinuation since onset), and 17 out of 53 SDNS/FRNS patients (31%) discontinued cyclosporine. However, 28 of the 53 patients (51%) relapsed. Although immunosuppressive agents did not extend B cell depletion, relapses were significantly less if immunosuppressive agents were continued after RTX (P = 0.006; hazard ratio = 0.2). Among the SRNS patients, complete (n = 6) and partial remission (n = 6) were achieved. No life-threatening adverse events were experienced.ConclusionsAlthough this was a multi-center survey where treatment of nephrotic syndrome varied between centers, the steroid-sparing effect of RTX in SDNS/FRNS was excellent. If single administration of RTX is chosen, continuation of immunosuppressive agents is recommended for prevention of relapse.

Long-Term Results of a Randomized Controlled Trial in Childhood IgA Nephropathy

BACKGROUND AND OBJECTIVES Children with IgA nephropathy showing diffuse (>80%) mesangial proliferation are at high risk for end-stage renal failure (ESRF). A previous controlled trial showed that combination therapy consisting of prednisolone, azathioprine, heparin-warfarin, and dipyridamole early in the course of disease reduces immunologic renal injury and prevents the progression of sclerosed glomeruli. The objective of this study was to evaluate the long-term effectiveness of combination therapy in children with IgA nephropathy showing diffuse mesangial proliferation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A secondary analysis of a multicenter, randomized, controlled trial involving 78 children with IgA nephropathy who received either 2-year combination therapy or heparin-warfarin and dipyridamole (control) therapy was conducted. RESULTS The median duration of observation was 10 years (range, 0.5 to 18). Two of 40 patients (5%) who received combination therapy and five of 34 patients (14.7%) who received control therapy developed ESRF. A Kaplan-Meier plot of renal survival showed that the outcomes of patients in the combined therapy group were better than those in the control therapy group (log-rank P = 0.03). The 10-year renal survival probability of each group was 97.1% (95% confidence interval, 81.4 to 99.6%) and 84.8% (95% confidence interval, 55.4 to 95.5%), respectively. The Cox proportional hazards model showed that the 2-year combination therapy was significantly associated with renal survival in both univariate and multivariate analyses. CONCLUSIONS Two-year combination therapy not only ameliorated the activity of the acute phase of nephritis but also improved the long-term outcome of severe childhood IgA nephropathy.

The Pharmacological Characteristics of Molecular-Based Inherited Salt-Losing Tubulopathies

CONTEXT Our understanding of inherited salt-losing tubulopathies has improved with recent advances in molecular genetics. However, the terminology of Bartter syndrome and Gitelman syndrome does not always accurately reflect their pathophysiological basis or clinical presentation, and some patients are difficult to diagnose from their clinical presentations. OBJECTIVE In the present study, we conducted molecular analysis and diuretic tests for patients with inherited salt-losing tubulopathies to clarify the pharmacological characteristics of these disorders. PATIENTS We detected mutations and subsequently conducted diuretic tests using furosemide and thiazide for 16 patients with salt-losing tubulopathies (two with SLC12A1; two with KCNJ1; nine with CLCNKB; and three with SLC12A3). RESULTS Patients with SLC12A1 mutations showed no response to furosemide, whereas those with SLC12A3 mutations showed no response to thiazide. However, patients with CLCNKB mutations showed no response to thiazide and a normal response to furosemide, and those with KCNJ1 mutations showed a good response to both diuretics. This study revealed the following characteristics of these disorders: 1) subjects with CLCNKB mutations showed one or more biochemical features of Gitelman syndrome (including hypomagnesemia, hypocalciuria, and fractional chloride excretion insensitivity to thiazide administration); and 2) subjects with KCNJ1 mutations appeared to show normal fractional chloride excretion sensitivity to furosemide and thiazide administration. CONCLUSIONS These results indicate that these disorders are difficult to distinguish in some patients, even when using diuretic challenge. This clinical report provides important findings that can improve our understanding of inherited salt-losing tubulopathies and renal tubular physiology.

Clinical practice guideline for pediatric idiopathic nephrotic syndrome 2013: general therapy

Nephrotic syndrome is a disorder characterized by severe proteinuria, hypoproteinemia, and generalized edema resulting from damage to the glomerular basement membrane. In Western countries, nephrotic syndrome affects 2 of 100,000 children per year [1]. In Japan, approximately 1,300 new cases per year of pediatric nephrotic syndrome are reported to the Medical Aid for Specific Chronic Disease of Children and the disease develops in 5 of 100,000 children per year. Approximately 90 % of the cases of pediatric nephrotic syndrome are idiopathic, or of unknown cause. The first-line treatment for an initial episode of pediatric idiopathic nephrotic syndrome is oral steroid therapy, which leads to remission in approximately 80 % of cases (steroidsensitive nephrotic syndrome) [2]. However, 80 % of children with steroid-sensitive nephrotic syndrome experience one or more relapses, [3] and 50 % of these children have frequent relapses [4]. Those with frequently relapsing nephrotic syndrome are prone to suffer steroid-induced side effects such as obesity, growth impairment, hypertension, diabetes mellitus, osteoporosis, and adrenal insufficiency. Many cases of steroid-resistant nephrotic syndrome, where steroids are ineffective, progress to renal failure. Pediatric idiopathic nephrotic syndrome is a very important disease in the field of pediatric nephrology. The Scientific Committee in the Japanese Society for Pediatric Nephrology previously published the ‘‘Clinical Practice Guideline for Pediatric Idiopathic Nephrotic Syndrome’’ (2013). This is the English translation from the ‘‘Medical Therapy’’ portion of the guideline.Nephrotic syndrome is a disorder characterized by severe proteinuria, hypoproteinemia, and generalized edema resulting from damage to the glomerular basement membrane. In Western countries, nephrotic syndrome affects 2 of 100,000 children per year [1]. In Japan, approximately 1,300 new cases per year of pediatric nephrotic syndrome are reported to the Medical Aid for Specific Chronic Disease of Children and the disease develops in 5 of 100,000 children per year. Approximately 90 % of the cases of pediatric nephrotic syndrome are idiopathic, or of unknown cause. The first-line treatment for an initial episode of pediatric idiopathic nephrotic syndrome is oral steroid therapy, which leads to remission in approximately 80 % of cases (steroidsensitive nephrotic syndrome) [2]. However, 80 % of children with steroid-sensitive nephrotic syndrome experience one or more relapses, [3] and 50 % of these children have frequent relapses [4]. Those with frequently relapsing nephrotic syndrome are prone to suffer steroid-induced side effects such as obesity, growth impairment, hypertension, diabetes mellitus, osteoporosis, and adrenal insufficiency. Many cases of steroid-resistant nephrotic syndrome, where steroids are ineffective, progress to renal failure. Pediatric idiopathic nephrotic syndrome is a very important disease in the field of pediatric nephrology. The Scientific Committee in the Japanese Society for Pediatric Nephrology previously published the ‘‘Clinical Practice Guideline for Pediatric Idiopathic Nephrotic Syndrome’’ (2013). This is the English translation from the ‘‘Medical Therapy’’ portion of the guideline.

Rituximab-associated agranulocytosis in children with refractory idiopathic nephrotic syndrome: case series and review of literature

BACKGROUND Agranulocytosis has been reported as a delayed-onset complication of rituximab treatment. However, the exact incidence and risk factors of this complication in patients with nephrotic syndrome remain unknown. METHODS Records of 213 rituximab treatments for 114 patients with refractory nephrotic syndrome between February 2006 and April 2013 were reviewed to identify episodes of agranulocytosis (defined as an absolute neutrophil count of <500 mm(3)). RESULTS Eleven episodes of agranulocytosis were detected in 11 patients. Median time of onset of agranulocytosis was 66 days (range, 54-161 days) after rituximab treatment. Nine patients experienced acute infections and received antibiotics. All but one patient received granulocyte colony-stimulating factor. Agranulocytosis resolved in all cases within a median of 3 days. The incidence of agranulocytosis was 9.6% in total patients and 5.2% in all treatments. Median age of the 11 patients who developed agranulocytosis was 6.4 years at the first rituximab treatment, significantly younger than the median age of the 103 patients who did not (median, 12.5 years; P = 0.0009). Five patients received re-treatment with rituximab. No recurrence of agranulocytosis was observed in any patient. CONCLUSIONS It is important to pay extra attention to this clinically serious delayed-onset complication as it may be accompanied by life-threatening infections such as sepsis. Further clinical studies are needed to clarify its pathogenesis.

Decreased levels of inflammatory cytokines in immunoglobulin-resistant Kawasaki disease after plasma exchange.

The pathogenesis of coronary artery aneurysm (CAA) formation in Kawasaki disease (KD) remains unknown. However, inflammatory cytokines are thought to play an important role in KD. Patients with intravenous immunoglobulin (IVIG)-resistant KD are more likely to develop CAA. For such refractory patients, steroids and emerging infliximab (IFX) are used; however, further verification is required for their efficacy and safety. Plasma exchange (PE), which removes various inflammatory cytokines, has been used in Japan for over 15 years to prevent CAA in IVIG-resistant KD patients. The sequential change in inflammatory cytokines during the time course of PE has yet to be investigated. In this study, we measured plasma levels of 13 cytokines in nine children with IVIG-resistant KD before the start of PE (day 0: D0), as well as at 1 or 2 days (D1/2), and 4 or 5 days (D4/5) after starting PE. The median age of onset was 8 months (range: 3-53 months). Before PE, patients were treated with IVIG (median dose: 4 g/kg, range: 3-4 g/kg). The median starting period of PE was 8 days after the onset of fever (range: 6-21 days), while its duration was 3 days (range: 2-5 days). Among the 13 cytokines, interleukin-6, tumor necrosis factor-α, tumor necrosis factor receptor I (TNFR1), TNFR2, granulocyte colony-stimulating factor, and IL-17 were significantly lower at D4/5 compared with D0 and/or D1/2, reflecting the potential central efficacy of PE. While three patients developed moderate CAA, their condition regressed within 1 year. The removal of inflammatory cytokines could be the central efficacy of PE against refractory KD.

Disappearance of glomerular IgA deposits in childhood IgA nephropathy showing diffuse mesangial proliferation after 2 years of combination/prednisolone therapy

BACKGROUND The prognosis of children with severe IgA nephropathy showing diffuse mesangial proliferation is poor. However, the prognosis can be improved by combination therapy (prednisolone + azathioprine or mizoribine + warfarin + dipyridamole) or prednisolone alone over a 2-year period, and disappearance of glomerular IgA deposits is often observed. Details of the incidence and clinicopathological significance of glomerular IgA disappearance remain unclear. METHODS To investigate this phenomenon, we retrospectively screened and analysed 124 consecutive children (age ≤ 18 years at first biopsy) with newly diagnosed severe IgA nephropathy showing diffuse mesangial proliferation, who received combination therapy or prednisolone alone for 2 years and underwent repeat biopsies. RESULTS Among these patients, 90 received combination therapy, and 34 received prednisolone alone. After 2 years of treatment, 27 of the patients (21.8%) showed disappearance of glomerular IgA. Logistic analysis showed that IgA disappearance was associated with less severe urinary protein excretion at the end of treatment. Kaplan-Meier analysis of the long-term course revealed a significant difference in proteinuria-free survival after the 2-year treatment period between the patients with IgA disappearance and those without (P = 0.008; log-rank test). The Cox proportional hazards model showed that disappearance of glomerular IgA after the treatment was a factor significantly associated with proteinuria-free survival in both univariate and multivariate analyses. CONCLUSIONS The present results suggest that disappearance of IgA after 2 years of treatment indicates milder disease severity, even in patients with diffuse mesangial proliferation, and is a prognostic factor related to proteinuria-free survival.

Severe respiratory adverse events associated with rituximab infusion

Sirs, We read with great interest the article in Pediatric Nephrology entitled “Fatal pulmonary fibrosis after rituximab administration” by Chaumais et al. [1]. We believe that patients who have lung complications are at an extremely high risk of respiratory adverse events after rituximab infusion. Respiratory events, such as cough, bronchospasm, and dyspnea, are relatively common adverse effects of rituximab. At our center, 28 patients have received rituximab to date (21 with steroid-dependent nephrotic syndrome and 7 with steroid-resistant nephrotic syndrome). Ten (36%) of these patients have experienced respiratory events, such as an infusion reaction. Several case reports have described severe respiratory injuries associated with the use of rituximab, such as interstitial pneumonitis and acute respiratory distress syndrome, although the precise frequency is unknown. There have been 32 reports (total of 62 cases) of rituximabinduced severe respiratory adverse events [2]. In these reports, elderly people were considered to be at high risk, and most of the patients were older than 50 years (median age 62 years, range 9–88). Of these 62 patients (85%), 53 had lymphoma or B-cell lymphocytic leukemia, and 46 (74%) suffered from interstitial pneumonitis and other complications, including bronchiolitis obliterans with or without organizing pneumonia (4 patients), acute respiratory distress syndrome (3), organizing pneumonia (3), hypersensitivity pneumonia (2), and pulmonary fibrosis (1); for three patients, there was no definite diagnosis. Prompt initiation of steroid therapy appears to have conferred benefit, although some cases resulted in fatal outcomes (12 patients, 19%). Most of the patients reported were elderly, but there were two pediatric patients and, surprisingly, both of these children suffered from refractory nephrotic syndrome [1, 2]. Bitzan et al. reported a 14-year-old boy who suffered frequent relapsing nephrotic syndrome despite the use of various immunosuppressants [2]. Respiratory symptoms (cough, chest pain, fatigue, and fever) occurred 19 days after the last infusion of rituximab, and a chest computed tomography demonstrated the presence of diffuse, groundglass infiltrates in both lungs, which was compatible with interstitial pneumonitis. The patients respiratory symptoms improved without recurrence. However, he was successfully treated with prednisolone and antibiotics. It may be interesting to investigate whether pediatric patients with nephrotic syndrome have a high risk of interstitial pneumonitis. At the present time, we recommend that a routine chest radiograph is obtained before riuximab infusion is initiated. We believe that clinicians should be highly alert to the possibility of severe respiratory adverse events and should never administer rituximab to patients already suffering from lung disease, such as pleural effusion, pneumonia, and atelectasis.