Obinutuzumab in Frequently Relapsing and Steroid-Dependent Nephrotic Syndrome in Children

Treatment of nephrotic syndrome with anti-CD20 therapies in pregnancy: a case series and review of the literature

Membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) are autoimmune kidney diseases and the most common causes of nephrotic syndrome. Anti-CD20 monoclonal antibodies are now recommended as first-line therapy for MN. Anti-CD20 monoclonal antibodies are also effective in steroid-dependent or frequently relapsing nephrotic syndrome associated with MCD or FSGS. Many women eligible for these treatments are of childbearing age. The impact of anti-CD20 therapies on pregnancy and fetal outcomes remains uncertain, particularly in glomerular diseases. We describe three cases of patients with glomerular disease treated with anti-CD20 therapies in the context of pregnancy and review the literature.

Emerging pharmacotherapies for the treatment of childhood nephrotic syndrome

INTRODUCTION

Childhood nephrotic syndrome (NS) is a relatively rare condition but an important cause of morbidity. It is classified based on histopathology and response to corticosteroid therapy.

AREAS COVERED

Children with steroid-sensitive disease have a favorable long-term prognosis with maintenance of normal kidney function. However, nearly half of these patients have persistent disease activity requiring chronic corticosteroid therapy or exposure to second-line immunosuppressive agents. The identification of anti-nephrin antibodies in many patients with steroid-sensitive disease suggests immunotherapy to reduce pathogenic antibody formation may represent a qualitative advance in treatment. Children with steroid-resistant disease are likely to have focal segmental glomerulosclerosis (FSGS). There are no approved treatments for this condition. FSGS is a heterogeneous entity, and improvements in care will likely depend on molecular classification of subtypes based on the underlying disease mechanism. This approach will enable selection of treatments that match the cause of NS in each child for precision medicine therapy.

EXPERT OPINION

Children with NS today benefit from therapeutic options not previously available, but clinical decisions still rely on steroid responsiveness at disease onset. Continued advancement in treating NS requires collaboration between basic scientists and nephrologists and the organization of a clinical trial framework to evaluate novel therapies.

Obinutuzumab is effective for the treatment of rituximab-refractory PLA2R-associated membranous nephropathy

Background

Clinical experience with obinutuzumab in patients with rituximab-refractory phospholipase A2 receptor (PLA2R)-associated membranous nephropathy remains limited. This study aimed to evaluate the efficacy and safety of obinutuzumab in treating patients with rituximab-refractory PLA2R-associated membranous nephropathy.

Methods

A single-center retrospective study was conducted on 20 patients with rituximab-refractory PLA2R-associated membranous nephropathy who received two doses of 1 g obinutuzumab, administered 2 weeks apart. At 6 months, patients with urinary protein levels exceeding 3.5 g/d received an additional dose of 1-2 g obinutuzumab. The primary clinical outcome was a composite measure of complete or partial remission during follow-up. Continuous secondary outcomes included 24-hour urinary protein, serum albumin, serum creatinine, serum anti-PLA2R levels, and CD19 B-cell counts at the time of obinutuzumab infusion, at 3 months, and at the last visit.

Results

A total of 20 patients with clinical manifestations of nephrotic syndrome were included in this study, with a median follow-up period of 9 months. The mean age of the patients was 46.25 ± 13.05 years. At a median follow-up of 4.50 months (3.00-8.25 months) after obinutuzumab therapy, remission was achieved in 16 patients. Two patients (10%) achieved complete remission, while 14 (70%) attained partial remission. At baseline, 16 out of 20 patients tested positive for serum anti-PLA2R antibodies, and immunological remission was observed in 11 of these 16 patients during follow-up. All patients experienced B-lymphocyte depletion within 1 month after receiving obinutuzumab infusion and maintained this depletion at 3 months. B-lymphocyte reconstitution was noted in 4 out of 20 patients (20%) at 6 months. No patients experienced fatal adverse events.

Conclusion

Obinutuzumab mainly induces short-term partial remissions in patients with rituximab-refractory primary membranous nephropathy, which may be related to the short follow-up period. However, this study demonstrates that obinutuzumab is an effective and safe treatment for rituximab-refractory PLA2R-associated membranous nephropathy.

Obinutuzumab and Ofatumumab are More Effective Than Rituximab in the Treatment of Membranous Nephropathy Patients With Anti-Rituximab Antibodies

Introduction

Although rituximab has significantly improved outcomes for patients with membranous nephropathy, response to treatment is not universal and drug resistance can occur. One mechanism of resistance is the occurrence of antidrug antibodies. Obinutuzumab and ofatumumab are humanized and human monoclonal antibodies, respectively, that target B cells. These treatments have been shown to be effective in membranous nephropathy. However, obinutuzumab and ofatumumab have never been compared with rituximab in the treatment of patients with membranous nephropathy with anti-rituximab antibodies. We aimed to compare the efficacy and safety of obinutuzumab and ofatumumab with rituximab in patients with membranous nephropathy with anti-rituximab antibodies.

Methods

This international retrospective multicenter study enrolled 34 patients with membranous nephropathy from 5 nephrology departments in France, India, and Italy. All the patients had previously developed anti-rituximab antibodies. Nineteen patients received rituximab, 12 received obinutuzumab, and 3 received ofatumumab.

Results

Patients treated with obinutuzumab or ofatumumab were more likely to achieve clinical remission than those treated with rituximab at month 6 (87% vs. 37%, P = 0.005) and month 12 (87% vs. 42%, P = 0.01). Patients treated with obinutuzumab or ofatumumab were more likely to achieve immunological remission and B-cell depletion at month 6 than the patients treated with rituximab (92% vs. 56%, P = 0.04 and 93% vs. 35%, P = 0.002, respectively). No serious adverse events were reported in the obinutuzumab or ofatumumab group.

Conclusion

Obinutuzumab and ofatumumab are more effective than rituximab in treating patients with membranous nephropathy with anti-rituximab antibodies. Anti-rituximab antibodies should be systematically monitored, to determine appropriate treatment.

The role of obinutuzumab in rituximab-refractory membranous nephropathy and minimal change disease

Background

Obinutuzumab, a new-generation anti-CD20 monoclonal antibody, was originally developed to overcome resistance to rituximab in B-cell malignancies. There is limited research regarding the use of obinutuzumab in patients with rituximab-refractory membranous nephropathy (MN) and minimal change disease (MCD).

Methods

A retrospective analysis was performed at Changzheng Hospital from September 2022 to September 2024, and screened patients with rituximab-refractory MN or MCD. Participants were treated because they were refractory to rituximab and consented to receive infusions of obinutuzumab. Primary outcomes were defined as complete remission (CR, proteinuria <0.3 g/d) or partial remission (PR, proteinuria <3.5 g/d with a ≥50% reduction). Secondary outcome was immunological remission in patients with phospholipase A2 receptor (PLA2R)-related MN.

Results

Seven patients with MN and five with MCD were included in the cohort. Among patients with MN, six of seven (86%) achieved at least PR, of whom two patients reached CR with a median time to first remission (either PR or CR) of 8.0 months. Among patients with positive serum anti-PLA2R antibodies at baseline, all achieved an immunological response. No patients experienced a relapse during the follow-up period. Among patients with MCD, all patients achieved a CR with the median time of 1.0 months. Patients who were steroid-dependent or immunosuppressant-dependent were able to taper their medications in the short term without experiencing relapse. No treatment-related severe adverse events were reported.

Conclusions

Our study demonstrated that obinutuzumab represents a promising alternative therapeutic option for the management of rituximab-refractory MN and MCD.

Obinutuzumab as a viable therapeutic strategy in rituximab-refractory childhood frequently relapsing, steroid-dependent nephrotic syndrome that relapsed during B-cell depletion

A subgroup of children with frequently-relapsing, steroid-dependent nephrotic syndrome relapse during B-cell depletion after rituximab. A 15-year-old boy with focal segmental glomerulosclerosis became rituximab-refractory after 5 courses of treatments, with a relapse-free period shortened to 1 month. Circulating total and memory B-cells were undetectable at the time of relapse. A single infusion of obinutuzumab sustained relapse-free remission up to the last follow-up at 18 months. There was persistent hypogammaglobulinemia but no infection was observed. Obinutuzumab may be a viable option for attaining long-term remission with reasonable side effect profiles in patients who relapse during B-cell depletion after rituximab.

Low-dose obinutuzumab for steroid-dependent nephrotic syndrome complicated by recurrent rituximab-induced serum sickness and anti-rituximab antibodies

BACKGROUND

Rituximab-induced serum sickness (RISS) is a rare drug complication in patients with steroid-dependent nephrotic syndrome (SDNS).

CASE-DIAGNOSIS/TREATMENT

A 7-year-old boy with SDNS exhibited RISS recurrence 8 days after the third rituximab dose. At that time, the patient's antirituximab antibody (ARA) level was extremely high at > 5000 ng/mg, and his serum rituximab drug level was undetectable at < 0.2 μg/mL. Further, the patient had an early relapse with a short B-cell depletion period after the third rituximab dose. To address ARA-mediated rituximab resistance, a single infusion of obinutuzumab at a dose of 300 mg/m2 was administered. The treatment led to an extended B-cell depletion period of > 6 months and sustained disease remission for 15 months without significant adverse events such as hypogammaglobulinemia and neutropenia.

CONCLUSIONS

Low-dose obinutuzumab can be an effective and safe option for rituximab-resistant SDNS complicated by RISS and the development of ARA.

The autoimmune architecture of childhood idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome, the most common glomerular disorder in children, has long been considered an immune-mediated disease based on the efficacy of glucocorticoids at inducing remission. Nevertheless, the immune processes leading to podocytopathy have largely remained elusive. The success of B-cell depletion with rituximab, descriptions of B-cell dysregulation during active disease, and the most recent discovery of autoantibodies targeting the major podocyte antigen nephrin point to an autoimmune humoral etiology for idiopathic nephrotic syndrome. Investigations of the immune factors involved in idiopathic nephrotic syndrome pathogenesis have uncovered common features with other autoimmune disorders that will aid in prognostication and in guiding the expansion of our glucocorticoid-sparing therapeutic arsenal. In this review, we discuss the emerging autoimmune architecture of idiopathic nephrotic syndrome, with a specific focus on pediatric steroid-sensitive disease, including the podocyte-reactive B-cell response that causes anti-podocyte antibodies, the predisposing genetic factors that shape the podocyte-reactive immune landscape, and the immune triggers driving active disease.

Steroid pulse therapy in idiopathic nephrotic syndrome in the era of modern immunosuppressive treatment-still up to date?

BACKGROUND

Intravenous steroid pulses (SP) are successfully used for the treatment of patients with idiopathic nephrotic syndrome (INS) resistant to oral prednisone.

METHODS

We performed a retrospective analysis of all patients in the three pediatric nephrology centers of the Paris region from 2002 to 2022 who were resistant to a 30-day course of oral prednisone and who received SP for their first INS flare and analyzed their disease course over 4 years.

RESULTS

Forty-seven patients (17 girls), median age 3.4 years, were analyzed. Of them, 68% reached remission within 7 days of SP. No significant short-term side effects were noted. Half of the patients started immunosuppressive treatment immediately after their first remission and 62% of them relapsed at least once, whereas all the patients who did not receive immunosuppressive treatment since their first remission relapsed. Among the SP-sensitive patients, 75% needed calcineurin inhibitor (CNI) or B-cell depletion during their disease course to achieve stable remission. Forty-two percent of the whole cohort received B-cell-depleting agents. Among the 15 SP-resistant patients, all received CNI. Twelve/fifteen patients reached remission. After 4 years, 68% among the SP-sensitive patients and 87% of SP-resistant patients still had an active disease.

CONCLUSIONS

SP are helpful to obtain rapid remission in pediatric INS patients resistant to oral steroids. However, as most SP-sensitive patients need immunosuppressive drugs, mainly CNI and B-cell-depleting agents it could be interesting to discuss the possibility to start CNI directly after the 30-day course of prednisone instead of SP.

Successful Switch to Obinutuzumab in a Rituximab-Intolerant Child with Difficult-to-Treat Idiopathic Nephrotic Syndrome

Background: Idiopathic nephrotic syndrome (INS) is the most common cause of nephrotic syndrome in children. A hallmark of the disease is the rapid remission of proteinuria following a high dose of steroids. Recurrent disease or steroid dependence are common, leading to a high steroid burden and the introduction of steroid sparing therapy. Anti-CD20 antibodies have been increasingly used with excellent results in complicated INS. Nevertheless, their use can be limited by the occurrence of infusion-related reactions (IRRs). Methods: This report discusses further treatment options for children who are intolerant to RTX and presents the first report of a successful switch to obinutuzumab (OBI) for a child with difficult-to-treat steroid-dependent nephrotic syndrome (SDNS) and RTX intolerance who was unresponsive to a desensitization protocol. Results: A 12-year-old boy with SDNS since the age of 2, was treated with steroids, cyclophosphamide and cyclosporine A (CsA). Because of the prolonged use of calcineurin inhibitors, a course of rituximab (RTX) was planned. Unfortunately, during first infusion, the boy presented with IRR. A desensitization protocol following the first unsuccessful infusion also failed. Facing the risks of long-term cyclosporine therapy, a decision was made to switch to another type of anti-CD20 antibody. Obinutuzumab infusion with a modified premedication scheme was uneventful. Conclusions: Switching therapy to obinutuzumab may be considered an option in nephrotic children who are intolerant to RTX when alternative therapies have been exhausted. The addition of montelukast to premedication and employment of desensitization protocols may decrease the risk of infusion-related reactions to anti-CD20 agents.

Childhood idiopathic nephrotic syndrome: recent advancements shaping future guidelines

Childhood idiopathic nephrotic syndrome is an important pediatric kidney disease associated with significant morbidities and even mortality. Several guidelines have been developed to standardize the terminology and patient care among the pediatric nephrology community. Since the publication of these guidelines, there have been major breakthroughs in the disease management and the understanding of underlying pathogenesis through multi-omics investigations, including the identification of anti-nephrin autoantibodies, genetic susceptibility loci, and the pathogenic role of B cell subsets. In this educational review, we summarize the recent major advancements in idiopathic nephrotic syndrome and attempt to provide potential therapeutic approaches in both steroid-sensitive and steroid-resistant nephrotic syndrome that may shape future guideline development.

The Pathogenesis of Nephrotic Syndrome: A Perspective from B Cells

Background

Nephrotic syndrome is a special type of chronic kidney disease, the specific pathogenesis of which remains unclear. An increasing number of studies have suggested that B cells play an important role in the pathogenesis of nephrotic syndrome.

Summary

Idiopathic nephrotic syndrome is a common kidney disease in children. While previously believed to be primarily caused by T-cell disorders, recent research has shifted its focus to B cells. Studies have shown that B cells play a significant role in the pathogenesis of NS, potentially even more so than T cells. This article provides a comprehensive review of the involvement of B cells in the development of idiopathic nephrotic syndrome.

Key Messages

B cells are involved in the pathogenesis of nephrotic syndrome by producing autoantibodies and various cytokines.

Obinutuzumab May Be an Effective and Safe Option for Adult Minimal Change Disease and Focal Segmental Glomerulosclerosis Patients after Multitarget Therapy Including Rituximab

INTRODUCTION

Rituximab has proven effective and safe in pediatric and adult minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) patients with frequently relapsing nephrotic syndrome. However, its efficacy diminishes in several patients who experience nephrotic syndrome relapsing in short durations or failing to achieve remission. We aimed to explore the efficacy and safety of obinutuzumab, a novel anti-CD20 antibody, in these patients.

METHODS

A retrospective case series study at our center included 11 adult MCD or FSGS patients who presented with nephrotic syndrome characterized by short-duration relapses or lack of remission after multitarget therapy, including rituximab. Primary outcomes included the first relapse-free time, relapse rate during follow-up, and the use of immunosuppressants after obinutuzumab. All adverse events were recorded.

RESULTS

Eleven adult patients (median age 26.0 years, 81.9% males) received an average obinutuzumab dose of 2.0 (1.0, 2.0) g during a median follow-up period of 17.0 (12.0, 22.0) months. The first relapse-free time was 12.1 (10.8, 18.9) months. Two patients with FSGS experienced relapses, while the remaining maintained remission by the end of follow-up. Six patients (54.5%) achieved cessation of corticosteroids and immunosuppressants within 3 months after obinutuzumab. Adverse events were mostly mild.

CONCLUSION

Obinutuzumab may be an efficient and safe option for inducing remission in adult MCD and FSGS patients who presented with nephrotic syndrome relapsing in short durations or failed to achieve remission after multitarget therapy, including rituximab. It was effective in maintaining remission in MCD patients, while its efficacy in maintaining remission in FSGS patients remained uncertain.

Obinutuzumab as Initial or Second-Line Therapy in Patients With Primary Membranous Nephropathy

Introduction

B-cell lymphocytes have been demonstrated to play a key role in the pathogenesis underlying membranous nephropathy (MN). The aim of this study was to evaluate the therapeutic efficacy and safety of Obinutuzumab, a glycoengineered type II anti-CD20 monoclonal antibody in individuals with MN.

Methods

We retrospectively analyzed data from 59 consecutive patients with primary MN who provided consent to receive Obinutuzumab and were followed for at least 6 months. The primary outcomes were complete (proteinuria <0.3 g/d) or partial (proteinuria <3.5 g/d with ≥ 50% reduction) remission of proteinuria.

Results

Twenty patients received Obinutuzumab as initial therapy, and 39 patients were previously treated with at least 1 immunosuppressant (second-line therapy). Fifty patients (84.7%) achieved complete remission (CR) or partial remission (PR) of proteinuria during the median follow-up of 9.4 months. The likelihood of remission was significantly higher when Obinutuzumab was used as initial therapy than as second-line therapy after adjusting for the baseline estimated glomerular filtration rate (eGFR), 24-hour urinary protein levels, and anti-phospholipase A2 receptor (PLA2R) status (adjusted hazard ratio [HR], 4.5; 95% confidence interval [CI]: 2.1-9.5, P < 0.001). Circulating CD19+ B-cell count decreased to <5 cells/μl in all patients within 2 weeks after infusion. Serum anti-PLA2R concentrations decreased to <14 relative units (RU)/ml in 43 of 48 patients with PLA2R-related MN. After Obinutuzumab administration, a significant reduction in 24-hour urine protein and increase in serum albumin were observed. No serious adverse events were observed.

Conclusion

Obinutuzumab may represent a promising and well-tolerated therapeutic option for individuals with primary MN. The potential of Obinutuzumab was highlighted as an initial therapy for primary MN.

Case report: Effective treatment of rituximab-resistant minimal change disease with obinutuzumab in an adult

Background

Minimal change disease (MCD) is a common cause of adult nephrotic syndrome. Most adults with MCD achieve complete remission (CR) after initial steroid therapy. However, approximately 30% of adults who respond to steroids experience frequent relapses, becoming steroid-dependent and potentially developing refractory MCD. Treating refractory MCD in adults poses a significant challenge.

Main body

A 37-year-old woman presented to the nephrology department with a 6-year history of MCD. The diagnosis of MCD was confirmed via renal biopsy. She initially achieved CR with steroid treatment but experienced relapse during steroid tapering. Subsequent CR was achieved with a regimen of steroids and tacrolimus although multiple relapses occurred. Rituximab led to another CR, but its maintenance lasted only 6 months. The response to subsequent rituximab treatments was unsatisfactory. Ultimately, obinutuzumab was selected, resulting in the induction and maintenance of CR for 12 months.

Conclusions

This case demonstrates the successful treatment of frequently relapsed, steroid-dependent, and rituximab-resistant MCD with obinutuzumab. Obinutuzumab is a promising therapeutic option for rituximab-resistant MCD.

Safety of Obinutuzumab in Children With Autoimmune Encephalitis and Early B-Cell Repopulation on Rituximab

BACKGROUND

Rituximab (RTX) resistance or early B-cells repopulation were observed in children but only few publications reported the use of Obinutuzumab and no recommendations were made concerning the dosage for children.

METHODS

This study was a single-center retrospective cohort study of all the children followed-up in the Pediatric Neurology Department of Necker-Enfants malades Hospital in Paris, France, and treated with obinutuzumab, between November 1, 2019, and November 1, 2021.

RESULTS

A total of eight children (three females, median age 4.5 years) were treated. Seven patients presented with autoimmune encephalitis and one with myeloradiculitis. The median delay of B-cell repopulation after a course of RTX was 87 days (range 41 to 160). A switch to obinutuzumab (anti-CD20) was performed for eight children. The median duration between the first RTX infusion and obinutuzumab administration was 6.6 months. The dosage regimen for obinutuzumab was one infusion of 1000 mg/1.73 m2, that is to say 580 mg/m2 (maximum 1000 mg/infusion), by extrapolation from the adult dosage. The median delay of B-cell repopulation after one course of obinutuzumab was 230 days (range 66 to 303 days) vs 87 days after one course of RTX (P < 0.01). None of the patients presented side effects with obinutuzumab treatment. All patients had a favorable evolution at the last-follow up. Median follow-up was 1.6 years.

CONCLUSIONS

This study reports the use of obinutuzumab in neurological inflammatory diseases in a pediatric population. Obinutuzumab seems to have a better biological efficacy than RTX with a longer time of B-cell repopulation.

An Updated Review of Membranous Nephropathy

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor (PLA2R) as a target antigen has led to a paradigm shift in the understanding and management of MN. At present, serum PLA2R antibodies are used for diagnosis, prognostication, and guiding treatment. Now, with the discovery of more than 20 novel target antigens, antigen mapping is almost complete. The clinical association of certain antigens provides clues for clinicians, such as the association of nerve epidermal growth factor-like 1 with malignancies and indigenous medicines. Serum antibodies are detected for most target antigens, except exostosin 1 and 2 and transforming growth factor-beta receptor 3, but their clinical utility is yet to be defined. Genome-wide association studies and studies investigating environmental factors, such as air pollution, shed more light on the underpinnings of MN. The standard therapy of MN diversified from cyclical cyclophosphamide and steroids to include rituximab and calcineurin inhibitors over the past decades. Here, we provide a cutting-edge review of MN, focusing on genetics, immune system and environmental factors, novel target antigens and their clinical characteristics, and currently available and emerging novel therapies in MN.