Predictors of relapse and long-term outcome in children with steroid-dependent nephrotic syndrome after rituximab treatment

Risk factors and retreatment for relapse in childhood primary nephrotic syndrome treated with rituximab

BACKGROUND

The effectiveness of rituximab (RTX) for steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS) in children is well documented. However, there are insufficient data on relapse risk factors. Additionally, the retreat regimen for relapsed children requires further investigation.

METHODS

We administered single dose RTX (375 mg/m2, maximum 500 mg) to children with SDNS/FRNS between May 2020 and December 2022. An additional single dose of RTX was administered when B-cell depletion (CD19 + B cells < 1%) was incomplete or B-cell recovery (CD19 + B cells ≥ 1%) occurred. Primary and secondary outcomes were the first and second relapse, respectively.

RESULTS

Eighty-nine patients were included and the observation period was 12.2-43.2 months. Thirty-three patients (37.1%) relapsed after RTX treatment. Multivariate analysis showed that previous steroid-resistant nephrotic syndrome (SRNS) history and low NK-cell percentage at initial RTX treatment were independent risk factors for first relapse. In the relapse group, 26 patients (78.8%) continued RTX treatment upon B-cell recovery. During mean follow-up period of (15.4 ± 8.1) months, 15 patients (45.5%) experienced a second relapse. Compared with non-continued RTX treatment group, the continued RTX treatment group had a lower relapse rate (34.6% (9/26) versus 85.7% (6/7); P = 0.047) and fewer relapses (0.0 (0.0, 0.6) versus 1.8 (0.9, 2.7) times/year; P = 0.004). Multivariate analysis showed that continued RTX treatment was the protective factor for second relapse.

CONCLUSION

Previous SRNS history and low NK-cell percentage at initial RTX treatment may be associated with higher risk of relapse. Despite the possibility of relapse during RTX treatment, continued RTX treatment is effective in reducing relapse.

The efficacy and dynamic changes of immune function of rituximab with mycophenolate mofetil in the treatment of steroid-dependent /frequently relapsing nephrotic syndrome: a retrospective follow-up study

INTRODUCTION

Approximately 70%～90% of children with steroid-sensitive nephrotic syndrome (SSNS) will suffer from steroid dependency or frequent relapses, prompting the use of steroid-sparing agent. In this study, we investigate the efficacy and the characteristics of dynamic changes in immune function of two doses of rituximab (RTX) in the treatment of steroid-dependent/frequently relapsing nephrotic syndrome (SDNS /FRNS).

METHOD

Retrospective follow-up study was conducted in our hospital from June 2022 to September 2023. 7 children with SDNS /FRNS were allocated to intravenous 2 doses RTX (each dose 375mg/m2, 1 dose per week) and administered the standard oral dose of mycophenolate mofetil (MMF) (1000-1200/m2/d, divided into 2 doses) when B cells have recovered (≥ 5/ul). The study subjects after treatment were monitored for the efficacy and dynamic changes of immune function for 12 months.

RESULT

7 children with SDNS/FRNS who were treated RTX with MMF and followed up for 12 months have no relapse. The rate of B cell depletion (< 5/ul) was 100% at 1 week after the second dose of RTX treatment, and the rate of B cell recovery was 100% at 5-12 months after the first dose of RTX treatment. There was no significant difference with T cell subsets (CD3, CD4, CD8, CD4/CD8) at each follow-up time points (all P > 0.05). The count of NK cells was significantly higher than that of other groups at 1 week after the second dose (P < 0.05). The IgM level at 1 week after the second dose was significantly lower than that before treatment and 1 week after the first dose (P < 0.05). There were no significant differences with IgA, IgG, C3 and C4 before treatment, 1 week after the first dose and 1 week after the second dose (all P > 0.05).

CONCLUSION AND RECOMMENDATION

Administering two doses of RTX along with the standard dose of MMF has been effective in maintaining remission for children with SDNS/FRNS. B cell depletion can be achieved one week after the second dose of RTX treatment. NK cell proliferation may play a role in B cell depletion, and early B cell depletion may suppress the production of IgM. These findings require further validation through additional clinical trials and basic research.

Prediction Model and Decision Analysis for Early Recognition of SDNS/FRNS in Children

Purpose

This study identified factors that identification of progression-predicting utility from steroid-sensitive nephrotic syndrome(SSNS) to steroid-dependent or frequently relapsing nephrotic syndrome (SDNS/FRNS) in patients and developed a corresponding predictive model.

Patients and Methods

This retrospective study analyzed clinical data from 756 patients aged 1 to 18 years, diagnosed with SSNS, who received treatment at the Department of Nephrology, Children's Hospital of Chongqing Medical University, between November 2007 and May 2023. We developed a shrinkage and selection operator (LASSO) - logistic regression model, which was visualized using a nomogram. The model's performance, validity, and clinical utility were evaluated through receiver operating characteristic curve analysis, confusion matrix, calibration plot, and decision curve analysis.

Results

The platelet-to-lymphocyte ratio (PLR) was identified as an independent risk factor for progression, with an odds ratio (OR) of 1.01 (95% confidence interval (CI) = 1.01-1.01, p = 0.009). Additionally, other significant factors included the time for urinary protein turned negative (OR = 1.17, 95% CI = 1.12-1.23, p < 0.001), estimated glomerular filtration rate(eGFR) (OR = 0.99, 95% CI = 0.98-0.99, p < 0.001), low-density lipoprotein (OR = 0.90, 95% CI = 0.83-0.97, p = 0.006), thrombin time (OR = 1.22, 95% CI = 1.07-1.39, p = 0.003), and neutrophil absolute counts (OR = 1.10, 95% CI = 1.02-1.18, p = 0.009). The model's performance was assessed through internal validation, yielding an area under the curve of 0.78 (0.73-0.82) for the training set and 0.81 (0.75-0.87) for the validation set.

Conclusion

PLR, eGFR, the time for urinary protein turned negative, low-density lipoprotein, thrombin time, and neutrophil absolute counts may be effective predictors for identifying SSNS patients at risk of progressing to SDNS/FRNS. These findings offer valuable insights for early detection and support the use of precision medicine strategies in managing SDNS/FRNS.

Long Term Evaluations of First Single-dose Rituximab in Children with Steroid-Dependent Minimal-Change Nephrotic Syndrome

OBJECTIVE

To explore the long-term efficacy and safety of the first single dose of rituximab in children with steroid-dependent minimal-change nephrotic syndrome (SD-MCNS) over a two-year period after infusion.

METHODS

A 2-year retrospective observational study was performed on children with SD-MCNS who received the first single dose of rituximab (375 mg/m2) from October 2011 to December 2018.

RESULTS

Seventy-seven patients (median age 8.17 years) were included. The efficacy of the first single-dose rituximab in children with SD-MCNS was 90.91% (70/77). An overall relapse rate of 78.33% was achieved. Older age at rituximab treatment onset (>8.46 years), a lower steroid-dependent dosage (<18.76 mg/m2·d) and a higher CD4+ T-cell count before rituximab treatment (>31.22%) were positively related to treatment efficacy (p < 0.05). Male sex, younger age at rituximab treatment onset, a higher IgE level before rituximab treatment, and a higher white blood cell count and CD3+ T-cell count at the time of steroid withdrawal were associated with disease relapse (p < 0.05). A model for predicting relapse after rituximab treatment in SD-MCNS patients was established.

CONCLUSIONS

The first single-dose rituximab treatment for children with SD-MCNS was effective and safe. Greater efficacy was observed in patients who were older at rituximab treatment onset, had a lower steroid-dependent dosage, or had a higher CD4+ T-cell count before rituximab treatment. In contrast, younger male patients with a higher IgE level experienced an increased occurrence of relapse.

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.

Predictive factors of long-term disease remission after rituximab administration in patients with childhood-onset complicated steroid-dependent nephrotic syndrome: a single-center retrospective study

BACKGROUND

Despite the fact that rituximab (RTX)-associated adverse events may be relatively frequent in younger patients, recent studies have reported RTX as a suitable first-line steroid-sparing agent for maintaining remission in children with steroid-dependent nephrotic syndrome (SDNS). However, the impact of age at RTX initiation on the long-term outcome remains unknown in this cohort.

METHODS

We retrospectively reviewed the clinical course of 61 patients with complicated SDNS who received a single dose of RTX (375 mg/m2) followed by maintenance immunosuppressive agents (IS) from January 2008 to March 2021. In patients who achieved > 12 months of prednisolone-free remission, IS tapering within 6 months was tried to achieve. The primary endpoint was the probability of achieving long-term treatment-free remission at the last follow-up.

RESULTS

After RTX initiation, 52 patients (85.2%) relapsed after a median of 665 days, and 44 patients (72.1%) received additional RTX doses (total, 226 infusions). At the last follow-up (median observation period, 8.3 years; median age, 18.3 years), 16 patients (26.2%) achieved long-term remission. Multivariate analysis showed that older age at RTX initiation was the independent predictive factor for achieving long-term remission (odds ratio, 1.25; p < 0.05). The proportion of those who achieved long-term remission was significantly higher in patients aged ≥ 13.5 years than in those aged < 13.5 years at RTX initiation (52.6 vs 14.3%, p < 0.05). Persistent severe hypogammaglobulinemia did not develop in older children (≥ 13.5 years) at RTX initiation.

CONCLUSION

For older children with complicated SDNS, RTX appeared to be a suitable disease-modifying therapy without persistent adverse events.

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.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-sensitive nephrotic syndrome

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given.

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 Curative Effect of Shuangshen Decoction Combined with Immunological Preparations in the Treatment of Pediatric Nephrotic Syndrome and Its Influence on the Rate of Complicated Infection and Recurrence

BACKGROUND

To explore the curative effect of Shuangshen Decoction combined with immunological preparations in the treatment of pediatric nephrotic syndrome and its influence on concurrent infection and recurrence rate.

METHODS

Ninety children with nephrotic syndrome were divided into the routine group and the combined group. The routine group received conventional treatment and immune agents, and the combined group was treated with Shuangshen Decoction on the basis of the routine group. The clinical indexes of the two groups were analyzed and followed up. The infection rate and recurrence rate were calculated.

RESULTS

The TCM syndrome scores in the combined group were significantly lower than those in the routine group. The total effective rate of the combined group was significantly higher than that of the routine group. The recurrence rate and infection rate of the combined group were significantly lower than those of the routine group. The incidence of adverse reactions in the combined group was significantly lower than that in the routine group.

CONCLUSION

Shuangshen Decoction combined with immune preparations is effective in treating pediatric nephrotic syndrome and can reduce the incidence of adverse reactions, infection rate, and recurrence rate.

Use of rituximab in paediatric nephrology

Rituximab is a chimeric monoclonal antibody capable of depleting B cell populations by targeting the CD20 antigen expressed on the cell surface. Its use in oncology, initially in B cell lymphoma and post-transplant lymphoproliferative disorders, predates its current utility in various fields of medicine wherein it has become one of the safest and most effective antibody-based therapies. It was subsequently found to be effective for rheumatological conditions such as rheumatoid arthritis and antineutrophil cytoplasmic antibody-associated vasculitis. Over the past decade, rituximab has generated a lot of interest in nephrology and has become an emerging or accepted therapy for multiple renal conditions, including systemic lupus erythematosus, lupus nephritis, vasculitis, nephrotic syndrome and in different scenarios before and after kidney transplantation. This review outlines its current use in paediatric nephrology practice, focusing on the knowledge required for general paediatricians who may be caring for children prescribed this medication and reviewing them on a shared care basis.

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.

Prophylactic rituximab administration in children with complicated nephrotic syndrome

BACKGROUND

Rituximab is effective for maintaining remission in patients with complicated nephrotic syndrome, although a history of steroid-resistant nephrotic syndrome (SRNS) is a risk factor for early relapse. We investigated the efficacy of prophylactic rituximab treatment for maintaining remission after B cell recovery.

METHODS

Patients with complicated steroid-dependent or frequently relapsing nephrotic syndrome with history of SRNS who received a single dose of rituximab (375 mg/m²) and continued immunosuppressive agents were enrolled in this retrospective study. Patients were divided into two groups: a prophylaxis group, which received additional rituximab treatment at B cell recovery and a non-prophylaxis group. The relapse-free period from the last rituximab infusion (the second treatment in prophylaxis group and the first treatment in non-prophylaxis group) was compared between two groups using the Kaplan-Meier method, and risk factors for early relapse were calculated using multivariate analysis by Cox proportional hazards model.

RESULTS

Sixteen patients in the prophylaxis group and 45 in the non-prophylaxis group were enrolled. Fifty-percent relapse-free survival after the last rituximab treatment was 667 days in the former and 335 days in the latter (p = 0.001). Multivariate analysis showed that additional rituximab treatment was the only significant negative factor for early relapse, with a hazard ratio of 0.40 (p = 0.02). Fifty-percent relapse-free survival after B cell recovery was much longer in the prophylaxis group (954 vs. 205.5 days, p = 0.003).

CONCLUSIONS

Additional rituximab treatment at B cell recovery can maintain prolonged remission even after B cell recovery in patients with complicated nephrotic syndrome with history of SRNS.

Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome

BACKGROUND

Anti-rituximab antibodies (ARA) are associated not only with adverse events, such as infusion reactions (IR) and serum sickness, but also with rituximab efficacy. However, the clinical relevance of ARA in children with steroid-dependent nephrotic syndrome (SDNS) remains unknown.

METHODS

We retrospectively reviewed clinical outcomes of 13 children with complicated SDNS receiving repeated single-dose rituximab treatments at 375 mg/m² to assess whether ARA formation could impact toxicity and efficacy of additional rituximab. Pre-rituximab 22 samples collected from patients who developed IR during the second or subsequent rituximab doses were measured by electrochemiluminescence analysis.

RESULTS

ARA were identified in 5 of 13 patients (9 of 22 samples). Median time to recovery of CD19⁺ B cells to > 1% of total lymphocytes and median relapse-free time after rituximab treatment were significantly shorter in the 9 ARA-positive samples than the 13 ARA-negative samples (41 vs. 100 days, p < 0.01 and 119 vs. 308 days, p < 0.05, respectively). Kaplan-Meier analysis showed that time to CD19+ B cell recovery after rituximab was significantly shorter in ARA-positive samples than in ARA-negative samples (p < 0.005). Severe IR developed in two ARA-positive patients and serum sickness in one ARA-positive patient.

CONCLUSIONS

The incidence of ARA formation was high in the pre-rituximab samples of patients with complicated SDNS who developed IR during the second or subsequent rituximab doses, suggesting that ARA formation might have an unfavorable impact on the toxicity and efficacy of additional rituximab doses in these patients.

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.

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.

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.

Long-term outcomes after early treatment with rituximab for Japanese children with cyclosporine- and steroid-resistant nephrotic syndrome

BACKGROUND

Although rituximab (RTX) may be effective treatment in children with nephrotic syndrome who are resistant to cyclosporine A and steroid (CsA-SRNS), long-term outcomes after B cell depleting therapy remain unclear.

CASE-DIAGNOSIS/TREATMENT

We retrospectively reviewed the clinical courses (median follow-up, 5.1 years) of six CsA-SRNS children (three boys; median age at RTX, 4.2 years) unresponsive to oral cyclosporine combined with ≥ 2 courses of intravenous methylprednisolone pulses, who received RTX within 6 months after disease onset (median 11 weeks). After initial RTX treatment (median two doses of 375 mg/m²) followed by retreatment with intravenous methylprednisolone pulses and/or high-dose prednisolone, all patients achieved complete remission at a median of 158 days. Although 17 relapses occurred in five patients during follow-up, all but one patient became steroid sensitive. Severe neutropenia and hypogammaglobulinemia developed in two and four patients, respectively. However, no life-threatening infections were identified in the cohort. At last visit (median age, 11.3 years), all patients maintained complete remission without renal insufficiency.

CONCLUSIONS

Although late-onset adverse events should be considered, particularly for young patients, early RTX treatment may have positive outcomes in children with CsA-SRNS in the long term.

Low-dose rituximab is no less effective for nephrotic syndrome measured by 12-month outcome

OBJECTIVE

Rituximab is an effective treatment for children with steroid dependent or frequently relapsing nephrotic syndrome. The optimum dosing schedule for rituximab has not been established. We hypothesized that a single low dose of 375 mg/m² would have comparable outcomes to higher doses in reducing the frequency of relapse and time to B cell reconstitution.

METHODS

We conducted a multicenter retrospective observational cohort study of children with steroid-sensitive frequently relapsing nephrotic syndrome. Data were extracted from clinical records including the dates of diagnosis, treatment, relapses, the use of concomitant immunosuppression, and lymphocyte subset profiling. Patients treated earlier received variable doses of rituximab, although typically two doses of 750 mg/m². Later, patients received the current regimen of a single dose of 375 mg/m². The primary outcome was an absence of clinically confirmed relapse 12 months following rituximab administration. Secondary outcomes were median time to relapse, probability of being relapse-free at 6 and 24 months and time to reconstitution of CD19⁺ B cells.

RESULTS

Sixty patients received 143 courses of rituximab. Seven different dosing regimen strategies were used, ranging between 375 and 750 mg/m² per dose, with administration of 1-4 doses. There was no significant difference in event-free survival at 12 months between dosing strategies. The median time to reconstitution of B cells was not significantly different between groups.

CONCLUSIONS

Use of a single low-dose regimen of rituximab in the management of frequently relapsing nephrotic syndrome does not affect the probability of relapse at 12 months or time to B cell reconstitution compared to a conventional higher dose.

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.