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

Efficacy and safety of long-term repeated use of rituximab in pediatric patients with nephrotic syndrome

BACKGROUND

We aimed to investigate the efficacy and safety of repeated use of rituximab (RTX) in pediatric patients with nephrotic syndrome (NS).

METHODS

Retrospective review of 50 patients with steroid-dependent NS (SDNS) who had received more than three cycles of RTX was conducted; each consisted of one to four infusions until B lymphocytes were depleted.

RESULTS

The median age of starting the first RTX cycle was 12.4 years (interquartile ranges (IQR) 10.2-14.6). During a median follow-up period of 6.3 (IQR 3.6-8.6) years, patients received a median of 5.0 RTX cycles (IQR 4.0-7.3). The number of relapses decreased from a median of 2.0 relapses per year (IQR 1.0-3.0) to 0.2 relapses per year (IQR 0.0-0.5) after long-term RTX treatments (P < 0.001). Longer relapse-free periods were associated with more than four RTX cycles, longer B-cell depletion, older age at each RTX treatment, and lower cholesterol levels. B lymphocytes recovered to 1% at a median of 5.9 months (95% confidence interval 5.7-6.1) after RTX administration. Factors related to a longer period of B-cell depletion included more than five RTX cycles, a higher dose of RTX, older age at treatment, and concurrent use of antimetabolites. During repeated RTX treatments, 8.0%, 6.0%, and 2.0% of patients developed hypogammaglobulinemia, severe infection, and severe neutropenia, respectively.

CONCLUSIONS

Long-term repeated use of RTX may be effective and safe in pediatric NS patients. Furthermore, the redosing of RTX could be chosen by considering predictive factors for relapse-free and B-cell depletion periods.

Changes in bone turnover markers after discontinuing long-term glucocorticoid administration in children with idiopathic nephrotic syndrome: a multicenter retrospective observational study

BACKGROUND

Glucocorticoids affect bone turnover. Little is known about how bone turnover changes when glucocorticoids are discontinued following long-term administration.

METHODS

This retrospective observational study was conducted on the relationship between discontinuation of long-term administration of glucocorticoid and bone turnover markers (BTMs) in patients with childhood-onset idiopathic nephrotic syndrome. Serum bone alkaline phosphatase (BAP), intact procollagen type 1 N-terminal propeptide (P1NP), and tartrate-resistant acid phosphatase-5b (TRACP-5b) were evaluated as BTMs.

RESULTS

Thirty-eight pairs of BTMs at glucocorticoid administration and after discontinuation were analyzed in 29 patients. The median age at baseline was 12.4 (interquartile range, 9.0-14.5) years, and the median time from the onset of nephrotic syndrome was 5.9 (3.3-9.7) years. The mean period from prednisolone discontinuation to the measurement of BTMs after glucocorticoid discontinuation was 3.5 ± 1.0 months. Changes in BTMs after glucocorticoid discontinuation were modest when the daily prednisolone dose was < 0.25 mg/kg/day (ln BAP standard deviation [SD] score, p = 0.19; log intact P1NP SD score, p = 0.70; TRACP-5b, p = 0.95). When the daily prednisolone dose was ≥ 0.25 mg/kg/day, all BTMs increased significantly after glucocorticoid discontinuation (ln BAP SD score, p < 0.01; log intact P1NP SD score, p < 0.01; TRACP-5b, p < 0.01).

CONCLUSIONS

Decreased BTMs can rise within a few months of discontinuing long-term glucocorticoid administration. When the administered glucocorticoid dose is low, changes in BTMs may be small. A higher resolution version of the Graphical abstract is available as Supplementary information.

A Systematic Review and Meta-analysis of Rituximab-Associated Infections Among Children and Adolescents With Glomerular Disease: Focus on the Risk of Infections

OBJECTIVE

This systematic review and meta-analysis aimed to explore rituximab (RTX) associated infectious complications in children with glomerular disease.

METHODS

We performed an electronic search of PubMed, International Scientific Information (ISI), Scopus, and EMBASE between January 2010 and July 2021. Infection rates and total drug-related adverse events were the outcomes. Statistical heterogeneity was evaluated by using the I2 statistic. When there was statistical evidence of heterogeneity (I2 > 50%, p > 0.1), a random-effect model was adopted. Data analysis was performed with Stata17.0 software.

RESULTS

A total of 7 studies with 668 patients (136 with lupus nephritis [LN] and 532 with nephrotic syndrome were included in the meta-analysis. The pooled risk ratio showed that the administration of RTX was significantly associated with lower risk of infectious complications in patients with LN and nephrotic syndrome (0.72 [95% CI 0.58, 0.85]) when compared with population data of patients without glomerular disease (p = 0.2). There was no significant difference between the LN and nephrotic syndrome groups in terms of total serious adverse events or the occurrence of infections. There was significant heterogeneity among the reported studies (Q = 42.39, p < 0.001, I2 = 81%).

CONCLUSION

Administration of RTX in children with glomerular disease is associated with a lower rate of infections when compared with population data of patients without LN or nephrotic syndrome. Additional high-quality randomized controlled trials with long-term follow-up are needed to identify the long-term potential complications. Trial registration PROPERO ID: CRD42021274869 (https://www.crd.york.ac/prospero/display_record.php?).

Rituximab therapy for childhood onset idiopathic nephrotic syndrome: experience of a Portuguese tertiary center

INTRODUCTION

Rituximab (RTX) is a therapeutic option in pediatric difficult-to-treat idiopathic nephrotic syndrome (NS). We aimed to assess the efficacy and safety of RTX use in these patients.

METHOD

A retrospective study of all patients with idiopathic NS treated with RTX was conducted in a pediatric nephrology division of a tertiary hospital. Demographic, anthropometric, clinical and analytical data were collected prior to treatment and at 6, 12, and 24 months.

RESULTS

Sixteen patients were included (11 males), with a median (25th-75th percentile, P25-P75) age at diagnosis of 2 (2.0-2.8) years. Fifteen were steroid-sensitive and 1 was steroid-resistant and sensitive to cyclosporine. The median age at administration of RTX was 10 (6.3-14.0) years. Throughout a median follow-up time of 2.5 (1.0-3.0) years, 6 (37.5%) patients achieved partial remission and 7 (43.8%) had no relapses and were not taking any immunosuppressants at the 24-month follow-up visit. Regarding complications, 1 patient presented persistent hypogammaglobulinemia. Compared with the 12-month period before RTX, there was a decrease in the median number of relapses at 6 and 12 months [3 (3.0-4.0) vs 0 (0-0.8) and 0.50 (0-1.0), respectively; p = 0.001] and in the daily steroids dose (mg/kg/day) at 6, 12, and 24 months [0.29 (0.15-0.67)vs [0.10 (0.07-0.13); p = 0.001], [0.12 (0.05-0.22); p = 0.005] and [0.07(0.04-0.18); p = 0.021]], respectively. There was also a reduction in the median BMI z score at 24 months [2.11 (0.45-3.70) vs. 2.93 (2.01-3.98); p = 0.049].

CONCLUSION

Our results confirm the efficacy and safety of RTX use in pediatric idiopathic NS and highlight its' potential cardiometabolic benefits.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome

Rituximab is an established therapy in children with idiopathic nephrotic syndrome to sustain short- to medium-term disease remission and avoid steroid toxicities. Recent trials focus on its use as a first-line agent among those with milder disease severity. Rituximab is used in multidrug refractory nephrotic syndrome and post-transplant disease recurrence, although the evidence is much less substantial. Available data suggest that the treatment response to rituximab depends on various patient factors, dosing regimen, and the concomitant use of maintenance immunosuppression. After repeated treatments, patients are found to have an improving response overall with a longer relapse-free period. The drug effect, however, is not permanent, and 80% of patients eventually relapse and many will require an additional course of rituximab. This underpins the importance of understanding the long-term safety profile on repeated treatments. Although rituximab appears to be generally safe, there are concerns about long-term hypogammaglobulinemia, especially in young children. Reliable immunophenotyping and biomarkers are yet to be discovered to predict treatment success, risk of both rare and severe side effects, e.g. , persistent hypogammaglobulinemia, and guiding of redosing strategy. In this review, we highlight recent advances in the use of rituximab for childhood nephrotic syndrome and how the therapeutic landscape is evolving.

Terapia com Rituximabe para síndrome nefrótica idiopática de início na infância: experiência de um centro terciário português

Resumo Introdução: Rituximabe (RTX) é uma opção terapêutica na síndrome nefrótica (SN) idiopática pediátrica de difícil tratamento. Visamos avaliar eficácia e segurança do uso de RTX nestes pacientes. Método: Realizou-se estudo retrospectivo de todos os pacientes com SN idiopática tratados com RTX, em uma unidade de nefrologia pediátrica de um hospital terciário. Dados demográficos, antropométricos, clínicos e analíticos foram coletados antes do tratamento e aos 6, 12 e 24 meses. Resultados: Incluímos 16 pacientes (11 do sexo masculino), com idade mediana (percentil 25–75, P25–P75) de 2 (2,0–2,8) anos ao diagnóstico. Quinze eram sensíveis a esteroides, e 1 resistente a esteroides e sensível à ciclosporina.A idade mediana na administração do RTX foi 10 (6,3–14,0) anos. Durante um tempo mediano de acompanhamento de 2,5(1,0–3,0) anos, 6 (37,5%) pacientes alcançaram remissão parcial e 7 (43,8%) não tiveram recidivas e não estavam tomando imunossupressor no acompanhamento aos 24 meses. Quanto às complicações,1 paciente apresentou hipogamaglobulinemia persistente. Comparado ao período de12 meses anterior ao RTX, houve diminuição no número mediano de recidivas em 6 e 12 meses [3 (3,0–4,0) vs 0 (0–0,8) e 0,50 (0–1,0), respectivamente; p = 0,001] e na dose diária de esteroides (mg/kg/dia) aos 6, 12 e 24 meses [0,29 (0,15–0,67) >vs [0,10 (0,07–0,13); p = 0,001], [0,12 (0,05–0,22); p = 0,005] e [0,07 (0,04–0,18); p = 0,021], respectivamente. Houve também redução na mediana do escore z do IMC aos 24 meses [2,11 (0,45–3,70) vs 2,93 (2,01–3,98);p = 0,049]. Conclusões: Nossos resultados confirmam a eficácia e segurança do uso de RTX em SN idiopática pediátrica, destacando seus potenciais benefícios cardiometabólicos.

Long-Term Efficacy and Safety of Repeated Rituximab to Maintain Remission in Idiopathic Childhood Nephrotic Syndrome: An International Study

BACKGROUND

Long-term outcomes after multiple courses of rituximab among children with frequently relapsing, steroid-dependent nephrotic syndrome (FRSDNS) are unknown.

METHODS

A retrospective cohort study at 16 pediatric nephrology centers from ten countries in Asia, Europe, and North America included children with FRSDNS who received two or more courses of rituximab. Primary outcomes were relapse-free survival and adverse events.

RESULTS

A total of 346 children (age, 9.8 years; IQR, 6.6-13.5 years; 73% boys) received 1149 courses of rituximab. A total of 145, 83, 50, 28, 22, and 18 children received two, three, four, five, six, and seven or more courses, respectively. Median (IQR) follow-up was 5.9 (4.3-7.7) years. Relapse-free survival differed by treatment courses (clustered log-rank test P<0.001). Compared with the first course (10.0 months; 95% CI, 9.0 to 10.7 months), relapse-free period and relapse risk progressively improved after subsequent courses (12.0-16.0 months; HRadj, 0.03-0.13; 95% CI, 0.01 to 0.18; P<0.001). The duration of B-cell depletion remained similar with repeated treatments (6.1 months; 95% CI, 6.0 to 6.3 months). Adverse events were mostly mild; the most common adverse events were hypogammaglobulinemia (50.9%), infection (4.5%), and neutropenia (3.7%). Side effects did not increase with more treatment courses nor a higher cumulative dose. Only 78 of the 353 episodes of hypogammaglobulinemia were clinically significant. Younger age at presentation (2.8 versus 3.3 years; P=0.05), age at first rituximab treatment (8.0 versus 10.0 years; P=0.01), and history of steroid resistance (28% versus 18%; P=0.01) were associated with significant hypogammaglobulinemia. All 53 infective episodes resolved, except for one patient with hepatitis B infection and another with EBV infection. There were 42 episodes of neutropenia, associated with history of steroid resistance (30% versus 20%; P=0.04). Upon last follow-up, 332 children (96%) had normal kidney function.

CONCLUSIONS

Children receiving repeated courses of rituximab for FRSDNS experience an improving clinical response. Side effects appear acceptable, but significant complications can occur. These findings support repeated rituximab use in FRSDNS.

The effect of rituximab on the quality of life of children with refractory nephrotic syndrome

BACKGROUND

Rituximab (RTX) is an effective treatment for maintaining remission in patients with nephrotic syndrome (NS), but there are few reports on the effect of RTX treatment on quality of life (QOL). The purpose of this study was to examine the effect of periodically repeated RTX treatment from the perspective of QOL.

METHODS

We systematically assessed the QOL of pediatric patients with refractory NS and parents' perceptions of their children's QOL through a 2 year RTX treatment protocol. Pediatric patients from Hokkaido University Hospital with refractory NS who met our specific criteria were enrolled between January 2015 and December 2015. The RTX infusion was performed 4 times at 6-month intervals, followed by mizoribine administration with early discontinuation of calcineurin inhibitors. Quality of life scores were measured by the Pediatric Quality of Life Inventory version 4.0 (PedsQL) at each RTX administration and evaluated 2 years later.

RESULTS

Twenty-two patients were analyzed. The patients' QOL and their parents' perceptions of their QOL improved over our 2 year treatment protocol. Nevertheless, the parents' scores were lower than the patients' scores on all scales, with slower improvement.

CONCLUSIONS

Our treatment protocol showed a significant improvement of QOL in patients with refractory NS. Although the risk of the RTX treatment should be considered, the treatment is useful for patients with refractory NS.

Rituximab Therapy for Adults with Nephrotic Syndromes: Standard Schedules or B Cell-Targeted Therapy?

Rituximab is a chimeric anti-CD20 monoclonal antibody. It acts mainly through complement-dependent cytotoxicity on B cells expressing the CD20 marker. In this review, we analyse the efficacy and possible pitfalls of rituximab to treat nephrotic syndromes by taking into account pharmacological considerations and CD19 marker testing utility. Despite the fact that the drug has been in use for years, efficacy and treatment schedules in adults with nephrotic syndrome are still a matter of debate. Clinical trials have proven the efficacy and safety of rituximab in idiopathic membranous nephropathy. Data from observational studies also showed the efficacy of rituximab in minimal change disease and focal segmental glomerulosclerosis. Rituximab use is now widely recommended by new Kidney Disease Improved Outcome (KDIGO) guidelines in membranous nephropathy and in frequent-relapsing, steroid-dependent minimal change disease or focal segmental glomerulosclerosis. However, rituximab response has a large interindividual variability. One reason could be that rituximab is lost in the urine at a higher extent in patients with nonselective nephrotic proteinuria, exposing patients to different rituximab plasma levels. Moreover, the association between CD19+ levels and clinical response or relapses is not always present, making the use of this marker in clinical practice complex. High resolution flow cytometry has increased the capability of detecting residual CD19+ B cells. Moreover, it can identify specific B-cell subsets (including IgG-switched memory B cells), which can repopulate at different rates. Its wider use could become a useful tool for better understanding reasons of rituximab failure or avoiding unnecessary retreatments.

Human or Chimeric Monoclonal Anti-CD20 Antibodies for Children with Nephrotic Syndrome: A Superiority Randomized Trial

BACKGROUND

The chimeric anti-CD20 monoclonal antibody rituximab is effective in steroid-dependent and calcineurin inhibitor-dependent forms of nephrotic syndrome, but many patients relapse at 1 year. Because ofatumumab, a fully human anti-CD20 monoclonal antibody, has a more extended binding site and higher affinity to CD20 compared with rituximab, it might offer superior efficacy in these patients.

METHODS

We designed a single-center randomized clinical trial to compare the long-term efficacy of ofatumumab versus rituximab in children and young adults with nephrotic syndrome maintained in remission with prednisone and calcineurin inhibitors. We randomized 140 children and young adults (aged 2-24 years) to receive intravenous ofatumumab (1.50 mg/1.73 m²) or rituximab (375 mg/m²). After infusions, oral drugs were tapered and withdrawn within 60 days. The primary outcome was relapse at 1 year, which was analyzed following the intent-to-treat principle. The secondary endpoint was relapse within 24 months from infusion, on the basis of urine dipstick and confirmed by a urine protein-to-creatinine ratio <200.

RESULTS

At 12 months, 37 of 70 (53%) participants who received ofatumumab experienced relapse versus 36 of 70 (51%) who received rituximab (odds ratio [OR], 1.06; 95% confidence interval [95% CI], 0.55 to 2.06). At 24 months, 53 of 70 (76%) participants who received ofatumumab experienced relapse, versus 46 of 70 (66%) who received rituximab (OR, 1.6; 95% CI, 0.8 to 3.3). The two groups exhibited comparable B cell subpopulation reconstitution and did not differ in adverse events.

CONCLUSIONS

A single dose of ofatumumab was not superior to a single dose of rituximab in maintaining remission in children with steroid-dependent and calcineurin inhibitor-dependent nephrotic syndrome.

CLINICAL TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov (NCT02394119) and https://www.clinicaltrialsregister.eu/ctr-search/search (2015-000624-28).

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.

[Rituximab treatment in pediatric patients with steroid-dependent nephrotic syndrome: a tertiary hospital]

BACKGROUND

Corticosteroids have had a central role in the treatment of nephrotic syndrome. The management of these patients who become dependent to steroids is complex, involving different immunosuppressive drugs patterns. The monoclonal antibody anti CD20, Rituximab, is likely to have beneficial effects in cases of steroid-dependent nephrotic syndrome patients with no easy resolution, even when we cannot make a statement about the specific role in the impact. We bring our personal experience in pediatric patients treated with this medication during the last years, to provide a thorough overview and useful information about the role of Rituximab in this pathology.

METHODS

Retrospective study in patients with steroid-dependent idiopathic nephrotic syndrome controlled in the division of Pediatric Nephrology of a spanish tertiary hospital in those patients who had received at least one treatment cycle of Rituximab, at any moment along the evolution of the disease.

RESULTS

The study involved 8 patients. All of them previously received immunosuppressive therapy. The Rituximab were administered as an intravenous infusion, in a dose of 375 mg/m2, and all doses were administered in a period during which the disease was in remission. The depletion of lymphocytes B (CD 19%) were confirmed after the first dose of Rituximab except for one, with a lymphocyte count of 1%. The period of depletion lasts 10.3 months (median; range 6.5-16 months), and only one of the patients registered a relapse of the disease in this period. A reduction of relapses suffered by patients has been shown after the treatment began (3.6 relapses/year in the previous year to the start of the treatment vs. 0.1 relapses/year during the first year post-rituximab). The relapse-free survival in the first year reached 83.3% in patients who suffered more than one relapse (75% of patients), and without a relapse after the treatment began in 2 cases. One or more drugs could be removed in 87.5% of patients after the first cycle of rituximab. After the rituximab treatment, we reached a 96.5% decrease in the corticosteroids doses administered (28.5 mg/m2/day during the 3 months pre-treatment vs. 1 mg/m2/day in the last 3 months of patient monitoring). Not a significant observed adverse effect attributed to the drug after the post-rituximab monitoring period (median 46.5 months, range 5-97 months).

CONCLUSION

The favorable results reported after rituximab treatment in our patients seems to confirm the effectiveness of this drug in the steroid-dependent nephrotic syndrome, making that therapeutic option into consideration and legitimating the use of the drug in complex cases involving pediatric patients. Even so, it seems recommendable to design pertinent studies to clarify, among others, the optimum regimen of the treatment (dose, interval and cycles), clinical repercussion and potential adverse effects in long terms.

Glucose metabolism disorders in children with refractory nephrotic syndrome

BACKGROUND

Patients with refractory nephrotic syndrome (NS) are at high risk of medication-induced glucose metabolism disorders, because of their long-term use of diabetogenic medications, particularly glucocorticoids and calcineurin inhibitors (CNIs). However, there have been no comprehensive evaluations of glucose metabolism disorders in pediatric patients with refractory NS. Moreover, glucocorticoids and CNIs could not be discontinued in these patients until the effectiveness of rituximab on refractory NS was shown, and therefore, there has been limited opportunity to evaluate glucose metabolism disorders after discontinuation of these medications.

METHODS

Consecutive pediatric patients who started rituximab treatment for refractory NS were enrolled. Their glucose metabolism conditions were evaluated using the oral glucose tolerance tests (OGTT) and HbA1c levels at the initiation of rituximab treatment. Patients with glucose metabolism disorders at the first evaluation were reevaluated after approximately 2 years.

RESULTS

Overall, 57% (20/35) of study patients had glucose metabolism disorders, and 40% (8/20) of these patients were detected only by their 2-h OGTT blood glucose levels and not by their fasting blood glucose or HbA1c levels. Non-obese/non-overweight patients had significantly more glucose metabolism disorders than obese/overweight patients (p = 0.019). In addition, glucose metabolism disorders in 71% (10/14) of patients persisted after the discontinuation of glucocorticoids and CNIs.

CONCLUSIONS

Whether the patient is obese/overweight or not, patients with refractory NS are at high risk of developing glucose metabolism disorders, even in childhood. Non-obese/non-overweight patients who are at high risk of diabetes need extra vigilance.

Rituximab experience in children with nephrotic syndrome: what have we observed differently

AIM

We aimed to evaluate the efficacy of rituximab therapy in children with nephrotic syndromes and to share our experiences.

MATERIAL AND METHODS

Twelve children with nephrotic syndrome (four with steroid-dependent, eight with steroid-resistant nephrotic syndrome) who were treated with rituximab were retrospectively evaluated in terms of clinical and laboratory data and CD19-20 levels. All patients received rituximab (375 mg/m2) once weekly for 4 weeks. A proteinuria-free period under steroid therapy was not sought prior to initiating rituximab therapy.

RESULTS

The overall remission rates in patients with steroid-dependent and steroid-resistant nephrotic syndrome were 100% and 27%. Focal segmental glomerulosclerosis was diagnosed in six patients and the remission rate was 33% in this population. CD19 cell depletion was observed in 10 of the 12 children. Seven of the 10 patients with CD19 depletion achieved remission, whereas the other three had persistent nephrotic proteinuria despite CD19 depletion. Two patients without CD19 depletion never achieved remission. Relapse occurred in three of the seven patients associated with increased CD19.

CONCLUSION

We observed that rituximab could be given without waiting for a proteinuria-free period under steroid therapy. Our result suggest that administering four weekly doses of rituximab increases the likelihood of remission, considering the amount of drug lost in the urine of children with nephrotic proteinuria. However, our findings must be confirmed with dose-comparison studies conducted with larger populations and an evaluation of long-term adverse effects. Some patients did not achieve remission despite B cell depletion, which suggests that B cell depletion is necessary but insufficient for remission in nephrotic syndromes.

Relationships between the clinical phenotypes and genetic variants associated with the immunological mechanism in childhood idiopathic nephrotic syndrome: protocol for a prospective observational single-centre cohort study

INTRODUCTION

Idiopathic nephrotic syndrome (INS) is the most common glomerulopathy that results in childhood chronic kidney disease in China, but the relationships between different clinical phenotypes and immunological genetic variants observed in patients with INS are ambiguous and have not been well studied. A cohort study combined with whole exome sequencing might further identify the effects of immunological genetic variants on clinical phenotypes and treatment outcomes.

METHODS AND ANALYSIS

We describe a 3 year prospective observational single-centre cohort study to be conducted in the Children's Hospital of Chongqing Medical University in China. This study will recruit and investigate 336 patients with childhood-onset INS presenting with different clinical phenotypes. Whole exome sequencing will be conducted when patients progress to a confirmed clinical phenotype during follow-up. Relevant clinical and epidemiological data, as well as conventional specimens, will be collected at study entry and 1 month, 3 months, 6 months, 1 year, 2 years and 3 years after disease onset. After this cohort is generated, the immunological genetic variants of steroid-sensitive nephrotic syndrome without frequent relapse, steroid-resistant nephrotic syndrome and steroid-dependent/frequent relapse nephrotic syndrome will be evaluated.

ETHICS AND DISSEMINATION

The study protocol is approved by Ethics Committee of Children's Hospital of Chongqing Medical University (reference number 2018-140). The results will be disseminated through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR1800019795.

Rituximab for Children With Difficult-to-Treat Nephrotic Syndrome: Its Effects on Disease Progression and Growth

Background: Since the early 2000s rituximab (RTX) has been thought of as an alternative treatment for steroid-sensitive nephrotic syndrome (SSNS) and steroid-resistant nephrotic syndrome (SRNS). Objective: This study aimed to determine the effects of RTX treatment on disease outcome and growth in pediatric SSNS and SRNS patients. Materials and Methods: The medical records of pediatric SSNS and SRNS patients that began RTX treatment at the mean age of 10.8 ± 5.1 years between 2009 and 2017 were retrospectively reviewed. Additionally, the effect of RTX on growth was evaluated based on patient height, weight, and BMI z scores. Results: The study included 41 children, of which 21 had SSNS and 20 had SRNS. Mean age at diagnosis of NS was 5.8 ± 4.7 years. Mean duration of post-RTX treatment follow-up was 2.3 ± 1.6 years. Among the SSNS patients, 6 and 11 patients were steroid free and calcineurin inhibitor free at the last follow-up visit, respectively. The 1-year cumulative steroid and calcineurin inhibitor doses both decreased after RTX treatment, as compared to before RTX (P = 0.001 and P = 0.015, respectively). The median height z-score at the time of RTX initiation was -1.2 and the median height z-score at the last follow-up visit was -0.6 (P = 0.044). The median BMI z-score decreased from 1.6 (IQR; 0.9-3.0) at the time RTX was initiated to 1.1 IQR; [(-0.7)-2.5] at the last follow-up visit (P = 0.007). At the last follow-up visit 4 SRNS patients had complete remission and 4 had partial remission. The 1-year cumulative steroid dosage in the SRNS patients decreased significantly after RTX, as compared to before RTX (P = 0.001). The median height z-score at the time of RTX initiation was -0.8 and the median height z-score at the last follow-up visit was -0.7 (P = 0.81). The median BMI z-score decreased from 0.3 at the time RTX was initiated to -0.1 at the last follow-up visit (P = 0.11). Conclusion: RTX has a more positive effect on disease outcome and growth in SSNS patients than in those with SRNS.

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.

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.