Rituximab in steroid-dependent or frequently relapsing idiopathic nephrotic syndrome

Long-term B cell depletion associates with regeneration of kidney function

Background

Chronic kidney disease (CKD) is a common condition that increases mortality and the risk of cardiovascular and other morbidities regardless of underlying renal condition. Chronic inflammation promotes renal fibrosis. Recently, renal B cell infiltrates were described in chronic kidney disease of various etiologies beyond autoimmunity.

Methods

We here investigated B cells and indicators of tertiary lymphoid structure formation in human renal biopsies. Renal function was studied during long‐term B cell depletion in human patients with membranous nephropathy and with CKD of unknown origin.

Results

Cytokine profiles of tertiary lymphoid structure formation were detected in human renal interstitium in a range of kidney diseases. Complex B cell structures consistent with tertiary lymphoid organ formation were evident in human membranous nephropathy. Here, B cell density did not significantly associate with proteinuria severity, but with worse excretory renal function. Proteinuria responses mostly occurred within the first 6 months of B cell depletion. In contrast, recovery of excretory kidney function was observed only after 18 months of continuous therapy, consistent with a structural process. Renal tertiary lymphatic structures were also detected in the absence of autoimmune kidney disease. To start to address whether B cell depletion may affect CKD in a broader population, we assessed kidney function in neurologic patients with CKD of unknown origin. In this cohort, eGFR significantly increased within 24 months of B cell depletion.

Conclusion

Long‐term B cell depletion associated with significant improvement of excretory kidney function in human CKD. Kinetics and mechanisms of renal B cell aggregation should be investigated further to stratify the impact of B cells and their aggregates as therapeutic targets.

Extended infusion of rituximab combined with steroids is effective in inducing remission and reducing relapse in adult minimal change disease

Background

Minimal change disease is a common cause of nephrotic syndrome in adults. Higher relapse rate put patients at risk of steroids toxicity due to long-term exposure. Rituximab has been suggested to maintain long time remission and withdraw steroids and other immunosuppressants with fewer adverse events. However, optimal dose and dosing interval have not been explored.

Methods

Twenty-five patients were enrolled from 2017-10 to 2020-03 in Nanfang Hospital in China. Clinical and biological data were extracted from medical records and laboratory databases. Therapy composed of 375mg/m² rituximab once three weeks for 3 dose and corticosteroid was applied. Complete remission was defined as reduction of proteinuria to 0.3g/d. Remission rate, relapse rate, steroids used before and after rituximab therapy and adverse effects were documented at a mean time of 14.71 months.

Results

Twenty-two patients achieved complete remission for an average of 3.26 months and only 3 patients experienced one relapse respectively during the follow-up period. The mean remission maintenance time was 11.6 months, and was 5 months after steroids withdrawal. Steroids dose at last follow-up was 6.09mg/d, which was significantly reduced compared to 28.15mg/d before rituximab. Relapse rate before and after rituximab was 1.43 and 0.1, respectively. Only four minor adverse events were recorded.

Conclusions

Therapy consisted of 375mg/m² rituximab once three weeks for 3 dose combined with corticosteroid is effective in inducing remission in adult patients with minimal change disease. Both of the relapse rate and dose of steroids used are significantly decreased with fewer side effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02437-4.

Rituximab in children with steroid sensitive nephrotic syndrome: in quest of the optimal regimen

Rituximab has emerged as an effective and important therapy in children with complicated frequently relapsing and steroid-dependent nephrotic syndrome to induce long-term disease remission and avoid steroid toxicities. The optimal rituximab regimen is not totally well defined, and there are many varying practices worldwide. We will in this review describe how patient factors, rituximab dose, and use of maintenance immunosuppression affect treatment outcomes. Specifically, low-dose rituximab without concomitant immunosuppression is associated with shorter relapse-free duration while other regimens have comparable outcomes. Patients with more severe disease generally have worse response to rituximab. Although rituximab appears to be generally safe, there are growing concerns of chronic hypogammaglobulinemia and impaired immunity especially in young children. Reliable prognostications and biomarkers for guiding subsequent treatments to avoid excessive treatments are yet to be identified. In this review, we will outline the, as we see it, best approach of rituximab in childhood steroid sensitive nephrotic syndrome at the present state of knowledge.

Consolidation Treatment and Long-Term Prognosis of Rituximab in Minimal Change Disease and Focal Segmental Glomerular Sclerosis

Purpose

There is currently a lack of studies investigating long-term prognosis and the necessity of further rituximab (RTX) consolidation treatment for minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). The aim of this study was to evaluate the efficacy of RTX for these diseases and to investigate whether a consolidation treatment can lower risks of relapse and reinforce long-term remission.

Patients and Methods

A retrospective study was conducted. The relapse and remission of 70 patients treated with 1 course of RTX treatment (4 infusions of 375 mg/m2) over a median follow-up time of 27 months (12–60 months) were analyzed. The rates of patients that were able to achieve non-relapse for a duration of 24 months between RTX consolidation therapy and non-consolidation therapy were compared.

Results

There were 67 cases (95.71%) of remission and 3 cases (4.29%) of non-remission. The average number of relapses decreased from 3.7±2.5 times before the treatment to 0.8±1.8 times after treatment (P <0.001). The average avannual number of relapses decreased from 1.3±1.2 times/year to 0.2±0.3 times/year (P <0.001). The results from the Cox proportional-hazards model showed that the risk of relapse in patients who received RTX non-consolidation treatment was significantly higher than those with consolidation treatment (odds ratios (OR) 20.9, 95% confidence intervals (CI) OR 5.7–75.7, p<0.001). The 24-month relapse-free rate was also significantly higher in patients with consolidation therapy compared with non-consolidation therapy (86.36% vs 25%, p<0.001). No adverse events were recorded.

Conclusion

RTX is highly effective in treating MCD and FSGS, and RTX consolidation therapy may be recommended to reinforce long-term remissions.

Efficacy and safety of rituximab in adult frequent-relapsing or steroid-dependent minimal change disease or focal segmental glomerulosclerosis: a systematic review and meta-analysis

Background

The efficacy and safety of rituximab (RTX) in adult frequent-relapsing (FR) or steroid-dependent (SD) nephrotic syndrome (NS), including minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), are still inconclusive.

Methods

We performed a systematic review and meta-analysis registered in  PROSPERO (CRD42019148102) by pooling data of cohort studies or case series on adult patients with difficult-to-treat NS. Steroid-resistant NS was excluded. The primary outcomes were the complete remission (CR) rate and the relapse rate. Partial remission (PR) rate, no response (NR) rate and adverse events were the secondary outcomes. A random-effects model was performed for all the outcomes.

Results

We included 21 studies involving 382 adult MCD/FSGS subjects with a median follow-up duration from 12 to 43 months. RTX treatment induced a pooled 84.2% CR rate [95% confidence interval (CI): 67.7–96.3%], while MCD patients had a high 91.6% CR rate and FSGS patients a moderate 43% CR rate. However, 27.4% (95% CI 20.7–34.5%) of the patients relapsed during the follow-up. The pooled PR and NR rates were 5.8% (95% CI 1.2–12.5%) and 5.2% (95% CI 0.0–15.0%), respectively. RTX was associated with trivial adverse events and good tolerance.

Conclusions

In summary, by pooling results of current pilot studies, RTX may be an effective and relatively safe alternative for most adult FR or SD MCD/FSGS to displace calcineurin inhibitors or prednisone in the hierarchy of treatment. More clinical trials comparing RTX with other immunosuppressants and concerning the long-term adverse events are needed.

Rituximab in childhood steroid-sensitive nephrotic syndrome: are multiple subsequent courses safe and effective?

INTRODUCTION

Idiopathic nephrotic syndrome is the most common glomerular disease in children. The majority of patients respond well to steroids. However, the relapse rate is high and many develop steroid dependency. Although other immunosuppressive medicines are successfully used as steroid-sparing agents, some children still have frequent relapsing episodes. Rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, has shown to be effective in treating difficult frequently relapsing/steroid-dependent nephrotic syndrome (FR/SDNS). Data on the effectiveness and long-term treatment outcomes of repeated courses of RTX are, however, scarce.

MATERIAL AND METHODS

Children and young people with FR/SDNS, aged 1-18 years, who received RTX at Great Ormond Street Hospital (GOSH) from 2006 to 2018 were reviewed.

RESULTS

During these 12 years, 103 children with FR/SDNS received RTX infusions at GOSH. Among these, 58 cases needed repeated courses of RTX: 2, 3, 4, 5, 6 and 7 repeated courses were given to 21, 21, 7, 5, 1 and 3 patients, respectively. The overall median time to relapse post-RTX was 11 months (range 1-53 months). There was no change in relapse-free interval with subsequent courses of RTX. No difference was found between age groups, genders and ethnicities. No severe side effects were noted.

CONCLUSIONS

RTX seems to be safe even after several repeated courses. However, long-term follow-up and further studies are needed, with a focus on side-effects in particular.

The STARMEN trial indicates that alternating treatment with corticosteroids and cyclophosphamide is superior to sequential treatment with tacrolimus and rituximab in primary membranous nephropathy

A cyclical corticosteroid-cyclophosphamide regimen is recommended for patients with primary membranous nephropathy at high risk of progression. We hypothesized that sequential therapy with tacrolimus and rituximab is superior to cyclical alternating treatment with corticosteroids and cyclophosphamide in inducing persistent remission in these patients. This was tested in a randomized, open-label controlled trial of 86 patients with primary membranous nephropathy and persistent nephrotic syndrome after six-months observation and assigned 43 each to receive six-month cyclical treatment with corticosteroid and cyclophosphamide or sequential treatment with tacrolimus (full-dose for six months and tapering for another three months) and rituximab (one gram at month six). The primary outcome was complete or partial remission of nephrotic syndrome at 24 months. This composite outcome occurred in 36 patients (83.7%) in the corticosteroid-cyclophosphamide group and in 25 patients (58.1%) in the tacrolimus-rituximab group (relative risk 1.44; 95% confidence interval 1.08 to 1.92). Complete remission at 24 months occurred in 26 patients (60%) in the corticosteroid-cyclophosphamide group and in 11 patients (26%) in the tacrolimus-rituximab group (2.36; 1.34 to 4.16). Anti-PLA2R titers showed a significant decrease in both groups but the proportion of anti-PLA2R-positive patients who achieved immunological response (depletion of anti-PLA2R antibodies) was significantly higher at three and six months in the corticosteroid-cyclophosphamide group (77% and 92%, respectively), as compared to the tacrolimus-rituximab group (45% and 70%, respectively). Relapses occurred in one patient in the corticosteroid-cyclophosphamide group, and three patients in the tacrolimus-rituximab group. Serious adverse events were similar in both groups. Thus, treatment with corticosteroid-cyclophosphamide induced remission in a significantly greater number of patients with primary membranous nephropathy than tacrolimus-rituximab.

Rituximab for the maintenance of minimal change nephropathy - A report of two pregnancies

Rituximab targets the CD20 antigen expressed on B-lymphocytes and is used to treat recurrent minimal change disease, but experience of its use in pregnancy is limited. We describe a 28-year-old Caucasian female, with recurrent nephrotic syndrome secondary to minimal change disease. She had failed to respond to non-teratogenic alternative therapies. The patient was successfully maintained in remission with rituximab during two consecutive pregnancies. Rituximab (1 g) was administered at 14⁺⁶ weeks 14 weeks and 6 days during Pregnancy 1 and 500 mg administered at 23⁺⁴ weeks 23 weeks and 4 days of Pregnancy 2. Rituximab had no apparent effect on infant B-cell development in either pregnancy, as neonatal lymphocyte titres were within normal range. There were no maternal complications in either pregnancy. Neither infant encountered infection-related complications. Although rituximab administration during pregnancy appeared safe, evidence of placental transfer is reported with neonatal B-cell depletion, thus alternatives with known safety profiles in pregnancy should be considered before rituximab administration.

Rituximab in adult minimal change disease and focal segmental glomerulosclerosis - What is known and what is still unknown?

Primary forms of minimal change disease and focal segmental glomerulosclerosis are rare podocytopathies and clinically characterized by nephrotic syndrome. Glucocorticoids are the cornerstone of the initial immunosuppressive treatment in these two entities. Especially among adults with minimal change disease or focal segmental glomerulosclerosis, relapses, steroid dependence or resistance are common and necessitate re-initiation of steroids and other immunosuppressants. Effective steroid-sparing therapies and introduction of less toxic immunosuppressive agents are urgently needed to reduce undesirable side effects, in particular for patients whose disease course is complex. Rituximab, a B cell depleting monoclonal antibody, is increasingly used off-label in these circumstances, despite a low level of evidence for adult patients. Hence, critical questions concerning drug-safety, long-term efficacy and the optimal regimen for rituximab-treatment remain unanswered. Evidence in the form of large, multicenter studies and randomized controlled trials are urgently needed to overcome these limitations.

Comparison of treatment options in adults with frequently relapsing or steroid-dependent minimal change disease

Background

Studies comparing all treatment options for frequently-relapsing/steroid-dependent (FR/SD) minimal change disease (MCD) in adults are lacking.

Methods

Medical records of 76 adults with FR/SD MCD who were treated with corticosteroids as the first-line therapy were reviewed. Treatment options were compared for the time to relapse, change of therapy and progression (relapse on full-dose treatment).

Results

Second-line treatments included rituximab (RTX; n = 13), mycophenolate mofetil (MMF; n = 12), calcineurin inhibitors (CNI; n = 26) and cyclophosphamide (CTX; n = 16). During the second-line treatments, 48 (71.6%) patients relapsed at median 17 (range 2–100)  months. The majority of relapses occurred during dose tapering or off drug. Twenty of 65 (30.8%) changed therapy after the first relapse. The median time to relapse after the second line was 66 versus 28 months in RTX versus non-RTX groups (P = 0.170). The median time to change of treatment was 66 and 44 months, respectively (P = 0.060). Last-line treatment options included RTX (n = 8), MMF (n = 4), CNI (n = 3) and CTX (n = 2). Seven (41.2%) patients had a relapse during the last-line treatment at median 39 (range 5–112)  months. The median time to relapse was 48 versus 34 months in the RTX versus non-RTX groups (P = 0.727). One patient in the RTX group died presumably of heart failure. No major adverse event was observed. During the median follow-up of 81 (range 9–355)  months, no patients developed end-stage renal disease.

Conclusions

Relapse is frequent in MCD in adults. Patients treated with RTX may be less likely to require a change of therapy and more likely to come off immunosuppressive drugs.

Role of Sphingolipid Signaling in Glomerular Diseases: Focus on DKD and FSGS

Sphingolipids are well-recognized as major players in the pathogenesis of many human diseases, including chronic kidney disease. The kidney is a very sensitive organ to alterations in sphingolipid metabolism. The critical issues to be addressed in this review relate to the role of sphingolipids and enzymes involved in sphingolipid metabolism in the pathogenesis of glomerular diseases with a special focus on podocytes, a key cellular component of the glomerular filtration barrier. Among several sphingolipids, we will highlight the role of ceramide, sphingosine, sphingosine-1-phosphate and ceramide-1-phosphate. Additionally, we will summarize the current knowledge with regard to the use of sphingolipids as therapeutic agents for the treatment of podocyte injury in kidney disease.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

Efficacy of repeat-dose rituximab maintenance therapy for minimal change disease in adults

BACKGROUND

Rituximab (RTX) has been reported to effectively treat minimal change disease (MCD) in adults. However, the efficacy of RTX as maintenance therapy, especially in older patients, remains unclear. This study aimed to evaluate the efficacy of repeat-dose RTX maintenance therapy regardless of age.

METHODS

We retrospectively reviewed the clinical courses of 13 biopsy-proven adult MCD patients receiving RTX and evaluated the relapse rate, concomitant steroid and immunosuppressant use, relationship between B-cell depletion time and relapse, and adverse events.

RESULTS

Mean patient age at start of RTX therapy was 51.5 ± 20.1 years. Each RTX induction consisted of a single 375 mg/m² dose. One patient received two RTX doses with a 1-year interval. The remaining 12 patients received RTX at 6-month intervals up to four times after RTX introduction. The median observation period was 28 (16-60) months after RTX induction, median relapse frequency was significantly decreased from 0.83 (0.18-1.92) to 0 (0-0.71) times/year (P < 0.001), and median prednisolone dose was reduced from 25 (5-40) mg to 2.5 (0-10) mg (P < 0.001). CD19-positive B cells remained depleted during RTX administration in 6-month intervals. No serious adverse events were observed after RTX administration.

CONCLUSIONS

Repeat-dose RTX as maintenance therapy efficiently prevented recurrence and was well tolerated in adult MCD patients including older. This regimen has the potential to maintain prolonged remission. Future studies in larger cohorts are needed to identify the optimal dose and frequency and evaluate the long-term effectiveness and safety of this regimen.

Nanoparticles exhibit greater accumulation in kidney glomeruli during experimental glomerular kidney disease

Loss and dysfunction of glomerular podocytes result in increased macromolecule permeability through the glomerular filtration barrier and nephrotic syndrome. Current therapies can induce and maintain disease remission, but cause serious and chronic complications. Nanoparticle drug carriers could mitigate these side effects by delivering drugs to the kidneys more efficiently than free drug through tailoring of carrier properties. An important extrinsic factor of nanoparticle biodistribution is local pathophysiology, which may drive greater nanoparticle deposition in certain tissues. Here, we hypothesized that a "leakier" filtration barrier during glomerular kidney disease would increase nanoparticle distribution into the kidneys. We examined the effect of nanoparticle size and disease state on kidney accumulation in male BALB/c mice. The effect of size was tested using a panel of fluorescent polystyrene nanoparticles of size 20-200 nm, due to the relevance of this size range for drug delivery applications.Experimental focal segmental glomerulosclerosis was induced using an anti-podocyte antibody that causes abrupt podocyte depletion. Nanoparticles were modified with carboxymethyl-terminated poly(ethylene glycol) for stability and biocompatibility. After intravenous injection, fluorescence from nanoparticles of size 20 and 100 nm, but not 200 nm, was observed in kidney glomeruli and peritubular capillaries. During conditions of experimental focal segmental glomerulosclerosis, the number of fluorescent nanoparticle punctae in kidney glomeruli increased by 1.9-fold for 20 and 100 nm nanoparticles compared to normal conditions. These findings underscore the importance of understanding and leveraging kidney pathophysiology in engineering new, targeted drug carriers that accumulate more in diseased glomeruli to treat glomerular kidney disease.

Rituximab versus cyclophosphamide as first steroid-sparing agent in childhood frequently relapsing and steroid-dependent nephrotic syndrome

BACKGROUND

Approximately 50% of children with steroid-sensitive nephrotic syndrome (SSNS) will suffer from frequent relapses or steroid dependency, prompting the use of so-called steroid-sparing drugs. In this pilot study, we compare the efficacy and safety of rituximab to oral cyclophosphamide as first-line steroid-sparing medications.

METHODS

A prospective open-label non-randomized study of children with frequent relapsing or steroid-dependant SSNS. Exclusion criteria were steroid-resistant disease, prescription of immunosuppressive agents other than prednisolone or levamisole, evidence of impaired kidney function, leucopenia, or active infection. The recruited children were allocated either to the oral cyclophosphamide (3 mg/kg/day for 8 weeks) or intravenous rituximab treatment (two doses of 375 mg/m²/dose, 2 weeks apart) and were monitored for relapses and side effects for 12 months.

RESULTS

Forty-six subjects were included from two centers; 27 received cyclophosphamide and 19 received rituximab. One-year relapse-free survival was reached in 17 (58.6%) patients treated with cyclophosphamide compared to 16 (84.2%) with rituximab (adjusted HR 0.36; 95% CI 0.09-1.45; p = 0.151). The mean interval to relapse was 6.9 months in the cyclophosphamide group (N = 10) and 6.3 months in the rituximab group (N = 3). Both treatments were associated with a significant (p < 0.001) reduction in prescribed dose of oral alternate-day steroid from 1.02 to 0.36 mg/kg (cyclophosphamide) and 0.86 to 0.08 mg/kg (rituximab). Importantly, a significantly (p = 0.003) higher percentage of patients achieved complete withdrawal of steroid within 3 months of commencing study treatment in the rituximab (73.7%) versus cyclophosphamide (29.6%) group. Transient leucopenia was the most frequent adverse effect observed in the cyclophosphamide group (18.5%) and one patient (3.4%) had acute hepatotoxicity besides severe leucopenia and neutropenia in the 7th week of treatment with complete recovery with the withdrawal of cyclophosphamide and maintenance of remission. A minor infusion-related reaction in the form of a generalized macular skin rash was observed in one patient (5%) in the rituximab group.

CONCLUSIONS

Rituximab is non-inferior to cyclophosphamide and safe as a first-line steroid-sparing agent in children with SSNS. A larger multicenter study is required to assess superiority over cyclophosphamide. Graphical abstract.

Focal Segmental Glomerulosclerosis: State-of-the-Art and Clinical Perspective

Focal segmental glomerulosclerosis (FSGS) is a histological pattern of glomerular injury, rather than a single disease, that is caused by diverse clinicopathological entities with different mechanisms of injury with the podocyte as the principal target of lesion, leading to the characteristic sclerotic lesions in parts (i.e., focal) of some (i.e., segmental) glomeruli. The lesion of FSGS has shown an increasing prevalence over the past few decades and is considered the most common glomerular cause leading to ESKD. Primary FSGS, which usually presents with nephrotic syndrome, is thought to be caused by circulating permeability factors that have a main role in podocyte foot process effacement. Secondary forms of FSGS include maladaptive FSGS secondary to glomerular hyperfiltration such as in obesity or in cases of loss in nephron mass, virus-associated FSGS, and drug-associated FSGS that can result in direct podocyte injury. Genetic FSGS is increasingly been recognized and a careful evaluation of patients with atypical primary or secondary FSGS should be performed to exclude genetic causes. Unlike primary FSGS, secondary and genetic forms of FSGS do not respond to immunosuppression and tend not to recur after kidney transplantation. Distinguishing primary FSGS from secondary and genetic causes has a prognostic significance and is crucial for an appropriate management. In this review, we examine the pathogenesis, clinical approach to distinguish between the different causes, and current recommendations in the management of FSGS.

Rituximab in treatment of collapsing FSGS-A case series

BACKGROUND

Collapsing focal segmental glomerulosclerosis (cFSGS) is an aggressive glomerular disease presenting as a nephrotic syndrome that has lower rates of remission with conventional immunosuppressive therapy and rapidly progresses to end-stage-renal-disease (ESRD). We report eight cases of HIV-negative cFSGS treated with rituximab.

METHODS

The current report is a retrospective case series of cFSGS treated with rituximab from January 2011 to March 2020, at varying phases of the disease.

RESULTS

Eight out of the 70 cFSGS patients received rituximab. The median age of patients was 30 years (IQR 24.25-37.5); five patients were males. The median serum creatinine, mean serum albumin and median 24 hours urinary protein at presentation was 0.9 (IQR 0.66-1.27) mg/dL, 2.95 ± 1.15 g/dL, 4.87 (IQR 1.64-5.75) g/day, respectively. Two patients were steroid-resistant, one steroid and tacrolimus dependent, one steroid and cyclosporine dependent, two steroids and tacrolimus resistant, one steroid, tacrolimus, cyclophosphamide, mycophenolate mofetil resistant and one steroid-resistant and tacrolimus dependent before rituximab therapy. Rituximab was given either as targeted therapy (after an initial dose of 375 mg/m² ; patients having CD-19 levels >5/μL or >1% at 1 month received additional low-dose [100 mg] of rituximab), or weekly regimen. Five patients received CD-19 targeted rituximab; three received weekly doses of 375 mg/m² , cumulative doses being 820 ± 228.03 mg, and 1800 ± 721.11 mg, respectively. At the end of median follow-up of 15 months, five (62.5%) patients were in remission (three partial, two complete remissions), two (25%) were resistant to therapy; one (12.5%) progressed to ESRD.

CONCLUSION

Rituximab is reasonably safe and achieves/maintains remission in 60% of cFSGS cases.

Twelve-month outcome in juvenile proliferative lupus nephritis: results of the German registry study

BACKGROUND

Children presenting with proliferative lupus nephritis (LN) are treated with intensified immunosuppressive protocols. Data on renal outcome and treatment toxicity is scare.

METHODS

Twelve-month renal outcome and comorbidity were assessed in 79 predominantly Caucasian children with proliferative LN reported to the Lupus Nephritis Registry of the German Society of Paediatric Nephrology diagnosed between 1997 and 2015.

RESULTS

At the time of diagnosis, median age was 13.7 (interquartile range 11.8-15.8) years; 86% showed WHO histology class IV, nephrotic range proteinuria was noted in 55%, and median estimated glomerular filtration rate amounted to 75 ml/min/1.73 m². At 12 months, the percentage of patients with complete and partial remission was 38% and 41%, respectively. Six percent of patients were non-responders and 15% presented with renal flare. Nephrotic range proteinuria at the time of diagnosis was associated with inferior renal outcome (odds ratio 5.34, 95% confidence interval 1.26-22.62, p = 0.02), whereas all other variables including mode of immune-suppressive treatment (e.g., induction treatment with cyclophosphamide (IVCYC) versus mycophenolate mofetil (MMF)) were not significant correlates. Complications were reported in 80% of patients including glucocorticoid toxicity in 42% (Cushingoid appearance, striae distensae, cataract, or osteonecrosis), leukopenia in 37%, infection in 23%, and menstrual disorder in 20%. Growth impairment, more pronounced in boys than girls, was noted in 78% of patients.

CONCLUSIONS

In this cohort of juvenile proliferative LN, renal outcome at 12 months was good irrespectively if patients received induction treatment with MMF or IVCYC, but glucocorticoid toxicity was very high underscoring the need for corticoid sparing protocols. Graphical abstract.

Rituximab in maintaining remission in adults with podocytopathy

Rituximab is currently used after the conventional agents have failed in the management of steroid-dependent (SD)/ steroid-resistant (SR) podocytopathies and have a safer toxicity profile. We report 53 adults with podocytopathies who were managed effectively with CD19-targeted rituximab therapy.

METHODS

This was a prospective study carried out at a tertiary care centre in India between January 2014 and June 2019. Adults between 16 and 60 years with SD, frequently relapsing (FR), and SR nephrotic syndrome (NS) due to podocytopathy received rituximab in a CD19-targeted approach.

PRIMARY OUTCOME

Percentage of patients who were in remission at 6 and 12 months. Secondary outcome: Percentage of patients in remission at the last follow-up, rituximab dose and adverse events of rituximab therapy.

RESULTS

Fifty-three adults with SD/FR/SR NS received CD19-targeted rituximab. The median age at the time of first rituximab injection was 30.09 ± 13.21 (16.53) years. At the time of first rituximab infusion, all patients were in remission with steroids and/or calcineurin inhibitors (CNIs). Fifty (94.33%) patients were in remission at the end of 6 and 12 months and the last follow-up (median: 36 months). The mean total dose of rituximab at 1 year was 788.7 ± 128.1 (6 001 100) mg. At last follow-up (median 36 months), 42 (79%) patients did not require any additional CNI or steroids therapy. No serious adverse events to rituximab were noted.

CONCLUSION

CD19-targeted rituximab therapy is safe and efficacious in the management of SD/SR adult podocytopathy. Also, rituximab is effective in maintaining remission in treatment naïve adult SD or FR podocytopathy.

Clinical Response and Pattern of B cell Suppression with Single Low Dose Rituximab in Nephrology

Background

There is no consensus regarding dose and frequency of rituximab in nephrology with extrapolation of doses used in treating lymphoproliferative disorders. There are no guidelines on targeting initial and subsequent doses on the basis of CD19⁺ B cells.

Methods

Initially, 100 mg rituximab was given to 42 adults with steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN), and high-immunologic-risk kidney transplantation. Absolute and percentage levels of CD19 B cells and clinical status were assessed at baseline, days 30, 90, and 180, and at 1 year. Subsequent doses of rituximab were on the basis of CD19 B cell reconstitution and clinical response.

Results

CD19 B cell percentage decreased from 16.3 ± 7.6 to 0.3 ± 0.3 (P≤0.001), 1.9 ± 1.7 (P≤0.001), and 4.0 ± 4.5 (P=0.005) by 30, 90, and 180 days, respectively. Suppression of CD19 B cell count below 1% at days 30, 90, and 180 was seen in 40 of 42 (95.2%), 18 of 42 (42.9%), and 7 of 42 (16.7%) patients, respectively. Of 30 with SDNS and FRNS followed up for 1 year, 29 (96.7%) went into remission at day 30. Remission was sustained in 23 (76.6%) at day 180 and 21 (70%) at 1 year. There was a significant decrease (P<0.001) in the dose of steroids needed to maintain remission at 180 days after rituximab (0.27 ± 0.02 mg/kg to 0.02 ± 0.00 mg/kg). CD19 B cell percentage at 90 days correlated with relapse (P=0.001; odds ratio 1.42; 95% confidence interval, 1.25 to 2.57). Eighteen (60%) required an additional dose. Of five with MN, four achieved remission by 6 months, which was sustained in three by 1 year. Of the seven kidney transplant recipients, two had antibody-mediated rejections, although CD19 B cells were suppressed even at 1 year.

Conclusions

Low-dose rituximab induces sustained depletion of CD19 B cells for up to 90 days. Its role in preventing relapses in SDNS, FRNS, MN, and rejection needs further study.

Rituximab therapy for focal segmental glomerulosclerosis and minimal change disease in adults: a systematic review and meta-analysis

Background

Use of rituximab (RTX) for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) is widely described in children. Clinical evidence in adults is limited. The objective of this study was to determine the treatment outcomes of RTX in adults with FSGS and MCD.

Methods

Ovid MEDLINE, SCOPUS, and Cochrane Database of Systematic Reviews were searched up to September 2019. Out of 699 studies, we included 16 studies describing the treatment outcomes of rituximab in adult patients with FSGS or MCD. Results were reported in remission rate and relapse rate. Serious adverse events were also reported.

Results

A total of 16 studies were included in our review and analysis. All studies were observational studies and included a total of 221 patients (23.1% FSGS, 76.9% MCD). Mean follow-up duration was 26.3 ± 12.8 months. From the analysis of five studies with FSGS patients (n = 51), the overall remission rate and relapse rate of RTX therapy was 53.6% (95% CI, 15.8–87.6%) and 47.3% (95% CI, 25.4–70.2%), respectively. Complete remission occurred in 42.9%. In contrast, from the analysis of 11 studies with MCD patients (n = 170), the overall remission rate and relapse rate of RTX therapy was 80.3% (95% CI, 68.5–88.5%) and 35.9% (95% CI, 25.1–48.4), respectively. Complete remission occurred in 74.7%. Subgroup analyses showed that overall remission and relapse were not different after adjusted for study year and RTX dose for both FSGS and MCD. Incidence of serious adverse events was 0.092 events/year.

Conclusions

Rituximab may be considered as an additional treatment to the standard therapy for adult patients with FSGS and MCD. Remissions and relapses are similar between FSGS and MCD. Serious adverse effects of rituximab were uncommon. We encourage further randomized controlled trials to confirm the efficacy of rituximab therapy in these patients.

A Case of Frequently Relapsing Minimal-Change Nephrotic Syndrome with Steroid-Induced Psychiatric Syndrome Treated by Low-Dose, Short-Term Steroid Therapy in Combination with Cyclosporine

Adults with minimal-change nephrotic syndrome (MCNS) generally receive oral prednisolone (PSL) at an initial dosage of 1.0 mg/kg/day for a minimum of 4 weeks, with 80% of patients achieving clinical remission. However, relapses are frequent, necessitating repeated treatment with high-dose PSL. Long-term treatment with high-dose steroids increases the risk of steroid toxicities, such as diabetes mellitus, gastric complications, infections, osteoporosis, and steroid-induced psychiatric syndrome (SIPS), which may compromise the patient's quality of life. Strategies are therefore needed to reduce the dosage and duration of steroid therapy for frequently relapsing MCNS (FRNS). Here, we suggest a new combination therapy of low-dose and short-term steroid with cyclosporine (CsA). We encountered an adult patient who developed recurrence of FRNS with depression arising from SIPS and was treated using low-dose, short-term PSL combined with CsA. He was successfully treated with PSL at an initial dosage of 0.3 mg/kg/day (20 mg/day) for just 2 weeks combined with CsA, allowing earlier induction of complete remission. We then promptly reduced the dose of PSL to below a physiological dosage (5 mg/day) over 3 weeks without relapse after episodes of SIPS and quickly resolved psychiatric symptoms. CsA in combination with PSL can reduce the initial dosage of PSL, shorten the time to remission, and easily maintain clinical remission. This protocol appears clinically useful and potentially applicable as a future treatment strategy for FRNS troubled by SIPS.

Rituximab use in adult glomerulopathies and its rationale

Glomerulopathies are one of the leading causes of end-stage renal disease. In the last years, clinical research has made significant contributions to the understanding of such conditions. Recently, rituximab (RTX) has appeared as a reasonably safe treatment. The Kidney Disease: Improving Global Outcomes guidelines (KDIGO) recommended RTX only as initial treatment in antineutrophil cytoplasm antibody associated vasculitis (AAV) and in non-responders patients with lupus nephritis (LN), but these guidelines have not been updated since 2012. Nowadays, RTX seems to be at least as effective as other immunosuppressive regimens in idiopathic membranous nephropathy (IMN). In minimal-change disease, (MCD) this drug might allow a long-lasting remission period in steroid-dependent or frequently relapsing patients. Preliminary results support the use of RTX in patients with pure membranous LN and immunoglobulin-mediated membranoproliferative glomerulonephritis (MPGN), but not in patients with class III/IV LN or complement-mediated MPGN. No conclusion can be drawn in idiopathic focal segmental glomerulosclerosis (FSGS) and anti-glomerular basement membrane antibody glomerulonephritis (anti-GBM GN) because studies are small, heterogeneous, and scarce. Lastly, immunosuppression including RTX is not particularly useful in IgA nephropathy. This review presents the general background, outcomes, and safety for RTX treatment in different glomerulopathies. In this regard, we describe randomized controlled trials (RCTs) performed in adults, whenever possible. A literature search was performed using clinicaltrials.gov and PubMed.

Rituximab use in adult glomerulopathies and its rationale

Glomerulopathies are one of the leading causes of end-stage renal disease. In the last years, clinical research has made significant contributions to the understanding of such conditions. Recently, rituximab (RTX) has appeared as a reasonably safe treatment. The Kidney Disease: Improving Global Outcomes guidelines (KDIGO) recommended RTX only as initial treatment in antineutrophil cytoplasm antibody associated vasculitis (AAV) and in non-responders patients with lupus nephritis (LN), but these guidelines have not been updated since 2012. Nowadays, RTX seems to be at least as effective as other immunosuppressive regimens in idiopathic membranous nephropathy (IMN). In minimal-change disease, (MCD) this drug might allow a long-lasting remission period in steroid-dependent or frequently relapsing patients. Preliminary results support the use of RTX in patients with pure membranous LN and immunoglobulin-mediated membranoproliferative glomerulonephritis (MPGN), but not in patients with class III/IV LN or complement-mediated MPGN. No conclusion can be drawn in idiopathic focal segmental glomerulosclerosis (FSGS) and anti-glomerular basement membrane antibody glomerulonephritis (anti-GBM GN) because studies are small, heterogeneous, and scarce. Lastly, immunosuppression including RTX is not particularly useful in IgA nephropathy. This review presents the general background, outcomes, and safety for RTX treatment in different glomerulopathies. In this regard, we describe randomized controlled trials (RCTs) performed in adults, whenever possible. A literature search was performed using clinicaltrials.gov and PubMed.

Both the rituximab dose and maintenance immunosuppression in steroid-dependent/frequently-relapsing nephrotic syndrome have important effects on outcomes

Rituximab is an effective treatment for steroid-dependent/ frequently-relapsing nephrotic syndrome (SDFRNS) in children. However, the optimal rituximab regimen remains unknown. To help determine this we conducted an international, multicenter retrospective study at 11 tertiary pediatric nephrology centers in Asia, Europe and North America of children 1-18 years of age with complicated SDFRNS receiving rituximab between 2005-2016 for 18 or more months follow-up. The effect of rituximab prescribed at three dosing levels: low (375mg/m²), medium (750mg/m²) and high (1125-1500mg/m²), with or without maintenance immunosuppression (defined as concurrent use of corticosteroids, mycophenolate motile or calcineurin inhibition at first relapse or for at least six months following the rituximab treatment) was examined. Among the 511 children (median age 11.5 year, 67% boys), 191, 208 and 112 received low, medium and high dose rituximab, respectively. Within this total cohort of 511 children, 283 (55%) received maintenance immunosuppression. Renal biopsies were performed in 317 children indicating the predominant histology was minimal change disease (74%). Without maintenance immunosuppression, low-dose rituximab had a shorter relapse-free period and a higher relapse risk (8.5 months) than medium (12.7 months; adjusted hazard ratio, 0.62) and high dose (14.3 months; adjusted hazard ratio, 0.50; all significant). With maintenance immunosuppression, the relapse-free survival in low-dose rituximab (14 months) was similar to medium (10.9 months; adjusted hazard ratio, 1.23) and high dose (12.0 months; adjusted hazard ratio, 0.92; all non-significant). Most adverse events were mild. Thus, children receiving low-dose rituximab without maintenance immunosuppression had the shortest relapse-free survival. Hence, both rituximab dose and maintenance immunosuppression have important effects on the treatment outcomes.

[Minimal change disease and focal segmental glomerulosclerosis]

Minimal change disease (MCD) or minimal change glomerulonephritis and focal segmental glomerulosclerosis (FSGS) are the two major causes of nephrotic syndrome in children and young adults. Both disease entities resemble each other and can sometimes only be discriminated on the basis of their clinical courses. MCD and FSGS display two classical examples that share a common pathophysiology in which the glomerular podocyte and the cytoskeleton of its foot processes play important roles. Therefore, the term "podocytopathy" was introduced for both diseases. In this article, we compare their differences and similarities, and summarized new data on pathophysiology and treatment. In adults, only a renal biopsy including electron microscopy allows for the discrimination of MCD and FSGS and other differential diagnoses. The identification of a primary or secondary form of the disease is based on the clinical course. Data from studies on the treatment are sparse; hence, treatment is still based on high-dose steroids followed by additional immunosuppressive agents. In secondary forms, treatment of the underlying disease is elementary.

Rituximab therapy in adults with steroid-dependent nephrotic syndrome

INTRODUCTION

Patients with steroid-dependent nephrotic syndrome (SDNS) suffer frequent relapse with adverse effects caused by long-term prednisolone treatment. Recently, the chimeric monoclonal antibody against the protein CD20 (rituximab - RTX) was observed to be efficacious and safe in the treatment of patients with SDNS. We summarized the scientific literature to evaluate RTX therapy in the clinical management of SDNS.

MATERIAL AND METHODS

PubMed, EMBASE, and Cochrane Library databases were investigated from interception to 2019-6-6, without language limitation. The analysis was restricted to adults ≥ 19 years of age. Data were administered and analyzed through the Review manager 5.3 software.

RESULTS

After RTX treatment, relapse times, prednisolone dose, and proteinuria decreased, whereas serum albumin was increased. The clinical parameters blood pressure and total cholesterol diminished also, whereas bone mineral density was improved. Overall, RTX ameliorated the adverse effects of prednisolone. Moreover, the Th1/Th2 ratio was changed except for the CD19 and CD20 cell counts. Additionally, most of the adverse effects of RTX were mild and well tolerated.

CONCLUSIONS

In the studies that we considered, we concluded that RTX treatment was effective and safe in the therapy of patients with SDNS. Nevertheless, more randomized controlled trials are required to explore the mechanism of RTX action and verify its efficacy.

Pre-emptive rituximab in focal and segmental glomerulosclerosis patients at risk of recurrence after kidney transplantation

Background

The recurrence of proteinuria after kidney transplantation (KT) is a characteristic complication of focal segmental glomerulosclerosis (FSGS). It has been suggested that pre-emptive rituximab might prevent recurrences in patients at risk, but there is no agreement about which factors might help to identify such patients.

Methods

We studied 93 kidney transplants with biopsy-proven idiopathic FSGS in order to analyse if preventive rituximab treatment could decrease recurrences in patients at risk.

Results

Fifteen patients (16.1%) presented a recurrence after KT, but when we restricted the analysis to the 34 patients presenting nephrotic syndrome at primary disease onset, the recurrence diagnosis rate increased to 44.1%. All patients with recurrence had complete nephrotic syndrome at the time of diagnosis. After multivariate adjustment, the only significant risk factor for recurrence was the presence of complete nephrotic syndrome at diagnosis. Twelve of the 34 patients at risk for recurrence received rituximab at the time of transplantation. Clinical and analytical characteristics were similar in all patients at risk. The number of recurrences was similar among treated (50%) and non-treated patients (40.9%).

Conclusions

Nephrotic syndrome with hypoalbuminaemia at diagnosis is the most important feature to identify patients at risk of recurrence. Our data suggest that pre-emptive rituximab is not effective to prevent FSGS recurrences.

Co-Deposition of IgM and C3 May Indicate Unfavorable Renal Outcomes in Adult Patients with Primary Focal Segmental Glomerulosclerosis

BACKGROUND/AIMS

We aimed to investigate the effects of glomerular IgM and C3 deposition on outcomes of adult patients with primary focal segmental glomerulosclerosis (FSGS).

METHODS

In this retrospective analysis, 86 consecutive adult patients with biopsy-proven primary FSGS were stratified into 3 groups according to their histopathological features: IgM- C3-, IgM+ C3-, and IgM+ C3+. Primary outcome was defined as at least a 50% reduction in baseline estimated glomerular filtration rate (eGFR) or development of kidney failure, while complete or partial remission rates were secondary outcomes.

RESULTS

Glomerular IgM deposits were found in 44 (51.1%) patients, 22 (25.5%) of which presented with accompanying C3 deposition. Patients in IgM+ C3+ group had higher level of proteinuria (5.6 g/24 h [3.77-8.5], p = 0.073), higher percentage of segmental glomerulosclerosis (20% [12.3-27.2], p = 0.001), and lower levels of eGFR (69 ± 37.2 mL/min/1.73 m2, p = 0.029) and serum albumin (2.71 ± 0.85 g/dL, p = 0.045) at the time of diagnosis. Despite 86.3% of patients in IgM+ C3+ group (19/22) received immunosuppressive treatment, the primary outcome was more common in patients in the IgM+ C3+ group compared with patients in IgM+ C3- and IgM- C3- groups (11 [50%] vs. 2 [9%] and 11 [26.1%] respectively [p = 0.010]). Complete or partial remission rates were lower in patients in the IgM+ C3+ group (5/22, 22.7%), as well (p = 0.043). Multivariate Cox regression analysis revealed that IgM and C3 co-deposition was an independent risk factor associated with primary outcome (hazard ratio 3.355, 95% CI 1.349-8.344, p = 0.009).

CONCLUSIONS

Glomerular IgM and C3 co-deposition is a predictor of unfavorable renal outcomes in adult patients with primary FSGS.

Prolonged Impairment of Immunological Memory After Anti-CD20 Treatment in Pediatric Idiopathic Nephrotic Syndrome

Anti-CD20 therapy is effective in idiopathic nephrotic syndrome (INS). However, transient or sustained hypogammaglobulinemia predisposing to an increased risk of infectious diseases can follow treatment in some patients. We analyzed the long-term effects of anti-CD20 therapy on immunological memory in 27 frequently-relapsing/steroid-dependent INS pediatric patients after more than 4 years from the first and at least 2 years from the last anti-CD20 infusion. Twenty-one INS children, never treated with anti-CD20 and under an intense oral immunosuppression with prednisone, mycophenolate mofetil, and calcineurin inhibitors were also included as control group. Levels of circulating B-cell subpopulations, total serum immunoglobulins and IgG and memory B cells directed against hepatitis B virus (HBV) and tetanus were determined and correlated with clinical characteristics. Nine patients never relapsed after more than 2 years from the last anti-CD20 administration (5 after the first, 3 after the second, and 1 after the fifth infusion). At last follow-up, most patients showed a complete recovery and normalization of total (27/27), transitional (27/27), and mature-naïve B cells (25/27). However, a sustained and significant reduction of total memory (20/27) and switched memory (21/27) B cells was found in most patients. 11/27 patients showed hypogammaglobulinemia at last follow-up and, among these, four presented with a severe hypogammaglobulinemia (IgG < 160 mg/dl). In contrast, no patient in the control group developed a severe hypogammaglobulinemia. Age at the time of first anti-CD20 administration was positively associated with IgG levels at last follow-up (p = 0.008); accordingly, younger patients had an increased risk of hypogammaglobulinemia (p = 0.006). Furthermore, severe hypogammaglobulinemia and delayed switched memory B-cell reconstitution were more frequent in non-relapsing patients. Reduced IgG levels against HBV and tetanus were observed at baseline and further declined at last follow-up. Antigen-specific memory B-cells were induced by re-immunization, but specific IgG titers remained low. In conclusion, anti-CD20 therapy can be disease-modifying in some INS patients. However, a prolonged impairment of immunological memory occurs frequently, independently from the number of anti-CD20 infusions, particularly in younger patients. Re-immunization may be necessary in these patients.

Persistent CD-19 depletion by rituximab is cost-effective in maintaining remission in calcineurin-inhibitor dependent podocytopathy

AIM

A significant proportion of patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are either steroid dependent or steroid resistant, requiring long-term calcineurin inhibitors (CNI) use. Rituximab has more favourable safety profile. The present study was undertaken to evaluate the efficacy and safety of rituximab in CNI-dependent patients.

METHODS

This was a prospective observational study conducted from July 2014 to February 2018. Steroid-dependent nephrotic syndrome or steroid-resistant nephrotic syndrome (biopsy proven MCD/FSGS), who were CNI dependent were enrolled. Mean age at enrolment was 22.77 ± 7.45 years. All patients received rituximab at a dose of 375 mg/m² at entry in the study. CD-19 levels were monitored monthly and patients having CD-19 levels >5/μL and/or > 1% received additional low-dose (100 mg) of rituximab.

RESULTS

A total of 24 patients were followed up for 12 months. At the end of 6 and 12 months, 87.5% and 79.16% of the patients achieved remission, respectively. Eight (33.33%) patients developed relapse. The mean dose of rituximab in the first year was 791 mg. The average cost of rituximab in the first year was 487.17$. Rituximab was well-tolerated, with mild infusion reactions, respiratory tract infection and oral candidiasis in 5 (20.83%), 5 (20.83%) and 1 (4.17%) patient, respectively.

CONCLUSIONS

CD-19 targeted rituximab is a safe and cost-effective agent in remission maintenance in adults with CNI dependent. Over three-fourths of the patients with CNI-dependent podocytopathy maintain clinical remission with CD-19 targeted rituximab therapy.

Effect of different rituximab regimens on B cell depletion and time to relapse in children with steroid-dependent nephrotic syndrome

BACKGROUND

Several studies have demonstrated that rituximab (RTX) improves relapse-free survival in patients with steroid-dependent nephrotic syndrome (SDNS). However, these studies used various RTX regimens and there are few data comparing these regimens in children with SDNS. In this retrospective study, we assessed the effect of three different initial RTX regimens on both time to B cell reconstitution and to first relapse.

METHODS

Sixty-one SDNS patients receiving a first course of RTX were included. Group 1 received one injection of 100 mg/m², group 2 received one injection of 375 mg/m², and group 3 received two injections of 375 mg/m² at day 0 and day 7. Time to B cell reconstitution and time to first relapse and respective risk factors were studied.

RESULTS

Median time to B cell reconstitution was 2.5 [1.8-3.5], 5.0 [3.9-6.0], and 6.6 [4.6-7.8] months in groups 1, 2, and 3, respectively. RTX regimen was associated with time to B cell reconstitution (HRs group 2 vs. 3, 4.07 [1.96-8.48]; group 1 vs. 3, 11.13 [4.04-30.67]). One-year relapse-free survival was 50% [58-77], 59% [42-76], and 72% [46-87] in groups 1, 2, and 3, respectively. RTX regimen was associated with risk of relapse (HRs group 2 vs. 3, 1.55 [0.51-4.65]; group 1 vs. 3, 4.98 [1.15-21.60]).

CONCLUSIONS

The initial dose of rituximab impacts time to B cell reconstitution and the probability of relapse. Risk of relapse is also associated with patient characteristics, suggesting that RTX regimen could be modified for each patient to balance efficacy, cost, and side effects.

Periodically repeated rituximab administrations in children with refractory nephrotic syndrome: 2-year multicenter observational study

BACKGROUND

Rituximab (RTX) is effective in maintaining remission in patients with nephrotic syndrome (NS), but a standard protocol of RTX administration has not been established.

METHODS

This study was a 2-year multicenter observational study, in which consistent treatments and evaluations were performed. We enrolled pediatric patients with refractory NS between January 2015 and December 2015. RTX infusion was performed four times at 6-month intervals, followed by mizoribine pulse therapy with early discontinuation of calcineurin inhibitor (CNI). Primary endpoints were the relapse-free survival rate and the number of relapses after RTX administration. Secondary endpoints were changes in side effects associated with long-term steroid administration.

RESULTS

Twenty-two patients were analyzed. The relapse-free survival rate at 1 year and 2 years was 50 and 46%, respectively. Twenty-one patients accomplished our protocol and the frequency of relapse was reduced under the discontinuation of CNI. Although two patients were diagnosed with frequent relapse and/or steroid dependency during the observation period, the frequency of relapse decreased with each rituximab dose. Statistically significant improvements in all steroid complications were observed in the final examination, but no significant improvements were observed from 1 to 2 years after RTX administration. One patient had agranulocytosis, and three patients showed electrocardiographic abnormalities.

CONCLUSIONS

Our protocol was useful and safe for refractory NS. However, RTX administration four times might have been excessive in patients who had no relapse by 1 year after the initial RTX administration. Further investigation of the most appropriate method of RTX administration is required.

Altered B-Lymphocyte Homeostasis in Idiopathic Nephrotic Syndrome

Background: B-cell-deleted therapy has been successfully used for children with idiopathic nephrotic syndrome (INS), suggesting that B cells may be involved in the pathogenesis of INS. B cells are a heterogenous population comprised of subpopulations distinguished by their phenotypes. However, few studies have focused on the alteration of B-cell homeostasis in INS. Methods: We measured the levels of B-cell subsets in the blood of 87 INS children via flow cytometry, prior to treatment with steroids. INS patients were divided into steroid-sensitive nephrotic syndrome (SSNS) and steroid-resistant nephrotic syndrome (SRNS) groups based on their sensitivities to steroids after a one-month follow-up. Subsequently, we compared these INS patients with age- and sex-matched patients with relapse (n = 35) and remissions (n = 32), as well as healthy controls (n = 75). Results: We found that 65 SSNS patients exhibited an altered peripheral-blood B-cell-subset distribution, with increased levels of total, transitional, memory, IgM (immunoglobulin M) memory and switched-memory B cells compared to 22 SRNS patients. The proportion of total B cells was significantly higher in the SSNS group (22.1 ± 6.7% L, p < 0.001) than in the SRNS, remission, and control groups. In contrast, the levels of B-cell subsets in SRNS patients were generally the same as those in remission patients and healthy controls. Patients in relapse presented elevated memory B cells compared to those in other groups. The area under the ROC (receiver operating characteristic) curve of transition B cells at initial onset for the prediction of SSNS was 0.907 (95% confidence interval, 0.835-0.979). The analysis rendered an optimal cut-off value of 2.05 (% Lymphocyte) corresponding to 79.1% sensitivity and 90.9% specificity. Conclusions: We observed and verified that B-cell subsets are significantly altered in children with SSNS. We propose that elevated transitional B cells may be a promising marker for predicting successful immunosuppressive therapy during the initial onset of INS. Further research is needed to determine the function of memory B cells in INS.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.

Multicenter analysis of the efficacy and safety of a non-standard immunosuppressive therapy with rituximab in children with steroid-resistant nephrotic syndrome

The aim of the study was a multicenter analysis of the efficacy and safety of a non-standard immunosuppressive therapy with rituximab (Rtx) in children with steroid-resistant nephrotic syndrome (SRNS) with particular emphasis on the possibility of permanent discontinuation or dose reduction of other immunosuppressive drugs such as glucocorticoids and cyclosporine A after 6 months of observation. The study group consisted of 30 children with idiopathic nephrotic syndrome, who were unresponsive to standard immunosuppressive treatment, and hospitalized in the years 2010-2017 in eight paediatric nephrology centres in Poland. The children were administered a single initial infusion of rituximab at the dose of 375 mg/m² of the body surface area. Proteinuria, the daily supply of glucocorticoids, and cyclosporine were assessed at the moment of the start of the treatment and after 6 months since its commencement. Before Rtx therapy, complete remission was found in 13 patients (43%) and partial remission was found in 8 patients (26%). These numbers increased to 16 (53%) and 12 (40%), respectively. At the start of the treatment 23 patients (76.6%) were treated with cyclosporine A. After 6 months, this number decreased to 15 patients (35%). At the start of the treatment, 18 patients (60%) were treated with prednisone. After 6 months, this number decreased to 8 patients (44%). Children with SRNS may potentially benefit from Rtx treatment despite relative risk of side effects. The benefits may include reduction of proteinuria or reduction of other immunosuppressants.

Boronic acid copolymers for direct loading and acid-triggered release of Bis-T-23 in cultured podocytes

We report an acid-reversible linker for triggered release of Bis-T-23, an experimental small molecule drug for kidney disease treatment that restores podocyte morphology during disease. Bis-T-23 contains catechols, which form an acid-reversible, covalent boronate ester bond with boronic acids. We synthesized phenylboronic acid-containing polymers using reversible addition-fragmentation chain transfer polymerization that were able to directly load and solubilize Bis-T-23. Because of the reversibility of the boronic ester bond, drug was released in its native form in a pH-dependent manner. The polymers rapidly trafficked into acidic compartments and did not exhibit cytotoxicity, and polymer-drug conjugates successfully delivered Bis-T-23 into cultured podocytes.

Emerging therapeutic strategies for minimal change disease and focal and segmental glomerulosclerosis

INTRODUCTION

Minimal change disease (MCD) and Focal and segmental glomerulosclerosis (FSGS) are two of the major causes of nephrotic syndrome (NS) in children and adults. According to KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, the treatment of adult primary MCD and FSGS should be based on immunosuppressants and antiproteinuric drugs. Recently, Rituximab, a humanized monoclonal antibody (mAb) has emerged as a potential treatment for steroid or calcineurin inhibitor-dependent patients; it has however demonstrated lower efficacy in those with nephrotic syndrome that is resistant to the above indicated drugs.

AREAS COVERED

Analysis of ongoing and already completed clinical trials, retrieved from clinicaltrials.gov, clinicaltrialsregister.eu and PubMed involving new therapies for nephrotic syndrome secondary to MCD and FSGS.

EXPERT OPINION

The most promising drugs under investigation for MCD and FSGS are mAbs. We are hopeful that new therapeutic options to treat multi-drug resistant MCD and FSGS will emerge from currently ongoing studies. What appears certain is the difficulty in enrolling patients affected by orphan renal diseases and the selection of valid endpoints in clinical trials, such as kidney failure.

Comparison of the response of frequently relapsing steroid-dependent minimal change nephrotic syndrome to rituximab therapy between childhood-onset and adult-onset disease

Rituximab has been approved in Japan for the treatment of intractable nephrotic syndrome, but in cases of childhood-onset disease only; its efficacy and safety in adult-onset disease has yet to be established. This study was undertaken to evaluate the efficacy of rituximab and adverse effects in patients with adult-onset minimal change nephrotic syndrome (MCNS).The study involved 32 childhood-onset cases (mean age at onset: 8.6 years) and 19 adult-onset cases (mean age at onset: 30.6 years) of frequently relapsing steroid-dependent MCNS, all of whom received intravenous rituximab drip infusion (375 mg/m body surface area per dose) at 4 time points at 6-month intervals. Relapse frequency, oral dose of immunosuppressants, and adverse effects were compared between the 2 groups.Remission was maintained in all cases in the childhood-onset and adult-onset groups; a significant reduction in relapse frequency was noted during the first 24 months of rituximab therapy (0.3 ± 0.7 times and 0.3 ± 0.6 times in the childhood-onset and adult-onset groups, respectively; P < .001). Oral corticosteroid therapy could be discontinued in 81.3% of cases of the childhood-onset group (26/32 cases) and in 70.6% of cases of the adult-onset group (12/17 cases); the oral corticosteroid dose was reduced significantly to 0.9 ± 2.5 mg/day in the childhood-onset group and to 0.8 ± 1.6 mg/day in the adult-onset group (P < .001). Cyclosporin treatment was also discontinued in 87.5% of cases in the childhood-onset group (21/24 cases) and in 80.0% of cases of the adult-onset group (15/21 cases); the oral cyclosporin dose was reduced significantly to 8.6 ± 27.4 mg/day and 9.2 ± 22.0 mg/day, respectively (P < .001). Regarding adverse reactions, infusion reactions developed at a frequency of 21.1% and 19.7% in both groups, respectively, with no significant inter-group difference (P = .72).Rituximab showed significant efficacy in adult-onset MCNS, with a comparable incidence of adverse reactions to that in childhood-onset cases, suggesting that this drug can also be used safely in adult-onset MCNS.

Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach

Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.

Therapeutic efficacy of rituximab for the management of adult-onset steroid-dependent nephrotic syndrome: a retrospective study

BACKGROUND

Recent reports have described the efficacy of rituximab in treating steroid-dependent nephrotic syndrome (SDNS) in pediatric patients. However, few reports describe data regarding adult-onset SDNS. We investigated the efficacy of rituximab for the management of adult-onset SDNS.

METHODS

We performed a retrospective cohort study investigating eight patients with adult-onset SDNS who were treated with rituximab. Clinical data were obtained at the initiation of rituximab therapy. The primary outcomes evaluated were successful suppression of relapses and CD19+ cells after rituximab treatment. The corticosteroid- and immunosuppressant-sparing effect and adverse events were additionally evaluated.

RESULTS

All eight patients were diagnosed with minimal change nephrotic syndrome and received immunosuppressants in addition to corticosteroid. Total number of relapses was 10.5 times as a median value. Rituximab administration was repeated in two patients, whereas six received single-dose rituximab. Three of eight (37.5%) patients showed relapse after rituximab therapy. A rituximab-induced depletion in CD19+ cells noted initially was followed by their reappearance in all patients. There were cases with no relapse after the reappearance of CD19+ cells. The median relapse time pre- and post-rituximab therapy showed a decrease from 1 time/year (interquartile range [IQR] 1-3 times/year) to 0 time/year (IQR 0-1 time/year). Rituximab treatment induced a significant reduction in the required doses of corticosteroid and cyclosporine (P < 0.01). No serious adverse events were observed.

CONCLUSION

Rituximab treatment was effective not only in childhood-onset but also in adult-onset SDNS. Further studies are needed to establish optimal treatment regimens.

Increased urinary angiotensin converting enzyme 2 and neprilysin in patients with type 2 diabetes

Angiotensin converting enzyme 2 (ACE2) and neprilysin (NEP) are metalloproteases that are highly expressed in the renal proximal tubules. ACE2 and NEP generate renoprotective angiotensin (1-7) from angiotensin II and angiotensin I, respectively, and therefore could have a major role in chronic kidney disease (CKD). Recent data demonstrated increased urinary ACE2 in patients with diabetes with CKD and kidney transplants. We tested the hypothesis that urinary ACE2, NEP, and a disintegrin and metalloproteinase 17 (ADAM17) are increased and could be risk predictors of CKD in patients with diabetes. ACE2, NEP, and ADAM17 were investigated in 20 nondiabetics (ND) and 40 patients with diabetes with normoalbuminuria (Dnormo), microalbuminuria (Dmicro), and macroalbuminuria (Dmacro) using ELISA, Western blot, and fluorogenic and mass spectrometric-based enzyme assays. Logistic regression model was applied to predict the risk prediction. Receiver operating characteristic curves were drawn, and prediction accuracies were calculated to explore the effectiveness of ACE2 and NEP in predicting diabetes and CKD. Results demonstrated that there is no evidence of urinary ACE2 and ADAM17 in ND subjects, but both enzymes were increased in patients with diabetes, including Dnormo. Although there was no detectable plasma ACE2 activity, there was evidence of urinary and plasma NEP in all the subjects, and urinary NEP was significantly increased in Dmicro patients. NEP and ACE2 showed significant correlations with metabolic and renal characteristics. In summary, urinary ACE2, NEP, and ADAM17 are increased in patients with diabetes and could be used as early biomarkers to predict the incidence or progression of CKD at early stages among individuals with type 2 diabetes.