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

In steroid-resistant nephrotic syndrome that meets the strict definition, monogenic variants are less common than expected

BACKGROUND

In patients with steroid-resistant nephrotic syndrome (SRNS), the presence of monogenic variants influences therapeutic strategies. Large cohort studies reported the detection of monogenic variants in approximately 30% of patients with SRNS. However, these cohorts included many patients, such as those with symptomatic proteinuria, who did not meet the strict diagnostic criteria for pediatric nephrotic syndrome (NS). Therefore, we investigated the proportion of causative monogenic variants detected in patients who strictly met the diagnostic criteria of SRNS and explored their clinical characteristics.

METHODS

We examined pediatric SRNS cases with genetic analysis conducted in our hospital. Cases satisfying all of the following criteria were included: (1) age at onset 1-18 years, (2) serum albumin at onset ≤ 2.5 g/dl, (3) persistent heavy proteinuria, and (4) no complete remission after 4 weeks of steroid monotherapy.

RESULTS

The proportion of detected monogenic variants was 12% (22/185) among all patients. The proportion was only 7% (9/129) in patients with edema at disease onset compared with 38% (9/24) in those without (p < 0.0001). Monogenic variants were rare in patients with acute kidney injury associated with NS (1% (1/11)) or a history of complete remission (4% (2/51)).

CONCLUSIONS

Our study revealed a monogenic cause in 12% of individuals with strictly defined SRNS, a much smaller proportion than previously reported. The presence or absence of edema at the onset was an important factor to distinguish SRNS with monogenic cause from SRNS without. Our results provide further evidence of the SRNS types attributable to monogenic causes.

Efficacy of rituximab and risk factors for poor prognosis in patients with childhood-onset steroid-resistant nephrotic syndrome: a multicenter study

BACKGROUND

The efficacy of rituximab in steroid-resistant nephrotic syndrome (SRNS) is controversial. We previously reported that rituximab in combination with methylprednisolone pulse therapy (MPT) and immunosuppressants was associated with favorable outcomes. We determined risk factors for poor response following rituximab treatment, which remains unknown.

METHODS

This retrospective study included 45 patients with childhood-onset SRNS treated with rituximab across four pediatric kidney facilities. Treatment effects were categorized as complete remission (CR), partial remission (PR), and no remission (NR) at one year after rituximab treatment. The primary outcome was the rate of CR, PR, and NR. Risk factors for non-CR were calculated with multivariate logistic regression. Adverse events and the relationship between disease status at one year and long-term prognosis were also evaluated.

RESULTS

The rates of CR, PR, and NR at one year were 69%, 24%, and 7%, respectively. The median time from rituximab administration to CR was 90 days. The median follow-up period after rituximab administration was 7.4 years. In multivariate analysis, significant risk factors for poor response were the pathologic finding of focal segmental glomerular sclerosis and a long interval between SRNS diagnosis and rituximab administration. The rates of CR were 90.3% and 21.4% in patients receiving rituximab within and after 6 months following SRNS diagnosis, respectively (p < 0.001). Five patients developed chronic kidney disease stage G5, including 2 of the 11 patients with PR and all 3 patients with NR, whereas none of the 31 patients with CR developed chronic kidney disease stage G5.

CONCLUSION

Early administration of rituximab in combination with MPT and immunosuppressants might achieve favorable outcomes in patients with SRNS.

Combined Methylprednisolone Pulse Therapy plus Rituximab for Treating a Rare Juvenile Steroid-Resistant Nephrotic Syndrome with Cerebral Venous Sinus Thrombosis: A Case Report

Background: Cerebral venous sinus thrombosis (CVST) secondary to nephrotic syndrome (NS) is rarely reported. Additionally, treating steroid-sensitive nephrotic syndrome (SSNS) that changes to steroid resistance (SRNS) is difficult, with many relapses and side effects. Case presentation: A 32-month-old SSNS male child turned into SRNS and developed cerebral venous sinus thrombosis (CVST), a rare complication of NS. As a result of the administration of combined pulse methylprednisolone and IV Rituximab (RTX) therapy, the patient showed marked improvement, the results of urine analysis were remarkably improved, and the child started to respond to treatment. Conclusion: Successful treatment of a rare case of juvenile SSNS behaving as SRNS with the development of CVST could be established using combined steroid pulse therapy, Enoxaparin, and the B lymphocytes monoclonal antibodies RTX.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

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.

Steroid-resistant Nephrotic Syndrome in Children: A Mini-review on Genetic Mechanisms, Predictive Biomarkers and Pharmacotherapy Strategies

Steroid-resistant nephrotic syndrome (SRNS) constitutes the second most frequent cause of chronic kidney disease in childhood. The etiology of SRNS remains largely unknown and no standardized treatment exists. Recent advances in genomics have helped to build understanding of the molecular mechanisms and pathogenesis of the disease. The genetic polymorphisms in genes encoding proteins which are involved in the pharmacokinetics and pharmacodynamics of glucocorticoids (GCs) partially account for the different responses between patients with nephrotic syndrome. More importantly, single-gene causation in podocytes-associated proteins was found in approximately 30% of SRNS patients. Some potential biomarkers have been tested for their abilities to discriminate against pediatric patients who are sensitive to GCs treatment and patients who are resistant to the same therapy. This article reviews the recent findings on genetic mechanisms, predictive biomarkers and current therapies for SRNS with the goal to improve the management of children with this syndrome.

[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.

Current understandings in treating children with steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatric nephrologists. SRNS is viewed as a heterogeneous disease entity including immune-based and monogenic aetiologies. Because SRNS is rare, treatment strategies are individualized and vary among centres of expertise. Calcineurin inhibitors (CNI) have been effectively used to induce remission in patients with immune-based SRNS; however, there is still no consensus on treating children who become either CNI-dependent or CNI-resistant. Rituximab is a steroid-sparing agent for patients with steroid-sensitive nephrotic syndrome, but its efficacy in SRNS is controversial. Recently, several novel monoclonal antibodies are emerging as treatment option, but their efficacy remains to be seen. Non-immune therapies, such as angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, have been proven efficacious in children with SRNS and are recommended as adjuvant agents. This review summarizes and discusses our current understandings in treating children with idiopathic SRNS.

Pediatric idiopathic steroid-sensitive nephrotic syndrome: diagnosis and therapy -short version of the updated German best practice guideline (S2e) - AWMF register no. 166-001, 6/2020

Idiopathic nephrotic syndrome is the most frequent glomerular disease in children in most parts of the world. Children with steroid-sensitive nephrotic syndrome (SSNS) generally have a good prognosis regarding the maintenance of normal kidney function even in the case of frequent relapses. The course of SSNS is often complicated by a high rate of relapses and the associated side effects of repeated glucocorticoid (steroid) therapy. The following recommendations for the treatment of SSNS are based on the comprehensive consideration of published evidence by a working group of the German Society for Pediatric Nephrology (GPN) based on the systematic Cochrane reviews on SSNS and the guidelines of the KDIGO working group (Kidney Disease - Improving Global Outcomes).

Baseline characteristics and long-term outcomes of steroid-resistant nephrotic syndrome in children: impact of initial kidney histology

BACKGROUND

Although many pediatric nephrologists consider focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) as separate clinical entities, whether the initial histology could affect clinical courses in children with steroid-resistant nephrotic syndrome (SRNS) suspected of having an immune-based etiology remains unknown, especially for long-term outcomes.

METHODS

We retrospectively reviewed long-term outcomes (> 3 years; median follow-up, 9.1 years) of 21 children with initial SRNS (FSGS, N = 9; MCD, N = 12) who achieved complete remission with immunosuppressive agents, including cyclosporine.

RESULTS

At NS onset, incidence of acute kidney injury (67% vs. 8%, P < 0.05) and proportion of patients with non-selective proteinuria (56% vs. 0%, P < 0.01) were significantly higher in the FSGS group than the MCD group. Furthermore, median days until complete remission after treatment was significantly longer in the FSGS group than the MCD group (116 days vs. 45 days, P < 0.001). Although subsequent biopsy histology of the 12 patients in the MCD group was still identical in all MCD, three of nine patients in the FSGS group were reclassified from FSGS to MCD at second biopsy. At last visit, all patients maintained complete remission, and none developed chronic kidney disease.

CONCLUSIONS

Initial presentation in the FSGS group was characterized by more severe clinical manifestations than the MCD group. If complete remission is achieved, FSGS and MCD in children with immune-mediated SRNS may constitute a single disease spectrum because the long-term outcomes are favorable, irrespective of initial histology.

Combination therapy of phosphatidylserine liposome with cyclosporine A improves nephrotoxicity and attenuates delayed-type hypersensitivity response

This study aimed to evaluate the antioxidant capacity of phosphatidylserine liposome (PS) against oxidative stress due to cyclosporine A (CsA) and concurrent administration of PS and CsA on the attenuation of immune response. The effect of oral PS was evaluated on biochemical and oxidative renal markers and histopathology of nephrotic rats receiving CsA. The effect of co-administration of PS with CsA was also assessed on DTH (delayed-type hypersensitivity) reaction of immunized rats. The cytokines production level of IL-2 (Interleukin-2) and IFN-γ (Interferon gamma) was measured in immunized rat's splenocytes. PS treatment significantly (P < 0.05) reduced Cr and BUN of serum and MDA (malondialdehyde) in kidney tissue, and increased SOD (superoxide dismutase) and CAT (Catalase) of kidney tissue in CsA-nephrotic rats. Histopathology data indicated significantly (P < 0.05) nephrotoxicity improvement after 25-day treatment with PS. Furthermore, CsA plus PS administration significantly reduced DTH response and cytokines production of IL-2 and IFN-γ in immunized rats. In conclusion, coadministration of CsA plus PS may overcome oxidative stress and improve the performance of organ transplantation or autoimmune therapy.

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

Idiopathic nephrotic syndrome newly affects 1-3 per 100,000 children per year. Approximately 85% of cases show complete remission of proteinuria following glucocorticoid treatment. Patients who do not achieve complete remission within 4-6 weeks of glucocorticoid treatment have steroid-resistant nephrotic syndrome (SRNS). In 10-30% of steroid-resistant patients, mutations in podocyte-associated genes can be detected, whereas an undefined circulating factor of immune origin is assumed in the remaining ones. Diagnosis and management of SRNS is a great challenge due to its heterogeneous etiology, frequent lack of remission by further immunosuppressive treatment, and severe complications including the development of end-stage kidney disease and recurrence after renal transplantation. A team of experts including pediatric nephrologists and renal geneticists from the International Pediatric Nephrology Association (IPNA), a renal pathologist, and an adult nephrologist have now developed comprehensive clinical practice recommendations on the diagnosis and management of SRNS in children. The team performed a systematic literature review on 9 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, formulated recommendations and formally graded them at a consensus meeting, with input from patient representatives and a dietician acting as external advisors and a voting panel of pediatric nephrologists. Research recommendations are also given.

Response to First Course of Intensified Immunosuppression in Genetically Stratified Steroid Resistant Nephrotic Syndrome

BACKGROUND AND OBJECTIVES

Intensified immunosuppression in steroid-resistant nephrotic syndrome is broadly applied, with disparate outcomes. This review of patients from the United Kingdom National Study of Nephrotic Syndrome cohort aimed to improve disease stratification by determining, in comprehensively genetically screened patients with steroid-resistant nephrotic syndrome, if there is an association between response to initial intensified immunosuppression and disease progression and/or post-transplant recurrence.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Pediatric patients with steroid-resistant nephrotic syndrome were recruited via the UK National Registry of Rare Kidney Diseases. All patients were whole-genome sequenced, whole-exome sequenced, or steroid-resistant nephrotic syndrome gene-panel sequenced. Complete response or partial response within 6 months of starting intensified immunosuppression was ascertained using laboratory data. Response to intensified immunosuppression and outcomes were analyzed according to genetic testing results, pattern of steroid resistance, and first biopsy findings.

RESULTS

Of 271 patients, 178 (92 males, median onset age 4.7 years) received intensified immunosuppression with response available. A total of 4% of patients with monogenic disease showed complete response, compared with 25% of genetic-testing-negative patients (P=0.02). None of the former recurred post-transplantation. In genetic-testing-negative patients, 97% with complete response to first intensified immunosuppression did not progress, whereas 44% of nonresponders developed kidney failure with 73% recurrence post-transplant. Secondary steroid resistance had a higher complete response rate than primary/presumed resistance (43% versus 23%; P=0.001). The highest complete response rate in secondary steroid resistance was to rituximab (64%). Biopsy results showed no correlation with intensified immunosuppression response or outcome.

CONCLUSIONS

Patients with monogenic steroid-resistant nephrotic syndrome had a poor therapeutic response and no post-transplant recurrence. In genetic-testing-negative patients, there was an association between response to first intensified immunosuppression and long-term outcome. Patients with complete response rarely progressed to kidney failure, whereas nonresponders had poor kidney survival and a high post-transplant recurrence rate. Patients with secondary steroid resistance were more likely to respond, particularly to rituximab.

Immunoglobulin serum levels in rituximab-treated patients with steroid-dependent nephrotic syndrome

BACKGROUND

Rituximab (RTX) is efficient in steroid-dependent nephrotic syndrome (SDNS) in pediatric and adult patients. The aim of this study is to describe hypogammaglobulinemia as a side effect of RTX treatment.

METHODS

All pediatric patients (< 18 years old) of four French pediatric nephrology centers who received RTX for SDNS between 2010 and 2015 have been included. Clinical and biological data have been analyzed retrospectively before, during, and after RTX treatment. Hypogammaglobulinemia was defined as an IgG level < - 2 standard deviations for patient age.

RESULTS

A total of 107 pediatric patients have been included, 65.9% were boys, median age at nephrotic syndrome diagnosis was 3.1 interquartile range [IQ 2.24-5.45] years and age at RTX introduction was 11.7 [IQ 8.6-14.2] years. Twenty-one patients had hypogammaglobulinemia before the initiation of RTX. Of the patients, 25/86 had at least one hypogammaglobulinemia during B cell depletion or after B cell recovery while IgG levels at initiation were normal with a persisting hypogammaglobulinemia for 13 patients 1 year after B cell recovery. Patients who developed hypogammaglobulinemia were younger at RTX initiation with a median age of 8.2 years [IQ 6.3-12.4]. Among all the 46 patients with hypogammaglobulinemia during follow-up, 13 had a concomitant infection.

CONCLUSIONS

Hypogammaglobulinemia is a frequent complication of RTX treatment in younger children treated for SDNS. The use of RTX in children has to be carefully evaluated and their clinical and biological follow-up should be adapted to the age-dependent risk profile for hypogammaglobulinemia.

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.

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.