Immunosuppression for adult steroid-dependent or frequently relapsing nephrotic syndrome: A systematic review and meta-analysis

OBJECTIVE

There is limited evidence on which immunosuppressive agents produce the best outcomes for adult patients with steroid-dependent or frequently relapsing nephrotic syndrome (SDNS/FRNS). This review compares the remission rate and adverse effects of various immunosuppressants used.

METHODS

Studies of adult patients with biopsy-proven SDNS/FRNS, administered any immunosuppressive agents and reported complete remission results as one of the clinical outcomes were included. Articles were independently screened by two researchers. ROBINS-I was used for risk of bias assessment. Random-effects model was used for statistical analysis and corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

574 patients across 28 studies were included in the analysis. Patients receiving rituximab have a complete remission rate of 89% (95% CI = 83% to 94%; τ2 = 0.0070; I2 = 62%; overall p < 0.01, low certainty) and adverse event rate of 0.26, cyclosporine (CR 40%; 95% CI = 21% to 59%; τ2 = 0.0205; I2 = 55%; overall p = 0.08, low certainty), tacrolimus (CR 84%; 95% CI = 70% to 98%; τ2 = 0.0060; I2 = 33%; overall p = 0.21, moderate certainty), mycophenolate mofetil (CR 82%; 95% CI = 74% to 90%; τ2 < 0.0001; I2 = 15%; overall p = 0.32, moderate certainty) and cyclophosphamide (CR 79%; 95% CI = 69% to 89%; τ2 = 0; I2 = 0%; overall p = 0.52, moderate certainty).

CONCLUSION

Among the commonly used immunosuppressive agents, only rituximab has a statistically significant effect in achieving complete remission among patients with SDNS/FRNS and has a relatively good safety profile, but this is limited by low quality of evidence with high degree of heterogeneity causing a lack of statistical power.

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.

Relapse during and after regular single-dose rituximab treatment in adult patients with steroid-dependent nephrotic syndrome

BACKGROUND

Rituximab is widely used in patients with steroid-dependent nephrotic syndrome. However, information on the effect of long-term rituximab treatment is limited. This study examined the efficacy of rituximab during and after treatment in adult patients with steroid-dependent nephrotic syndrome.

METHODS

This retrospective cohort study included 30 patients with steroid-dependent nephrotic syndrome. Patients received regular single-dose rituximab (500 mg) intravenously every 6 months. Discontinuation of rituximab was considered after four to six doses if there was no recurrence of nephrotic syndrome. Glucocorticoid discontinuation with remission, first relapse after rituximab initiation, and relapse after regular rituximab treatment discontinuation were evaluated.

RESULTS

The median age was 38 (range 18-67) years. Of 30 patients, 13 and 17 were men and women, respectively. Prior to rituximab treatment, the median number of nephrotic syndrome relapses in the patients was 5 (range 2- > 20). The 1 year discontinuation rate of glucocorticoids with remission was 83%. All patients discontinued glucocorticoid treatment at least once until 3 years and 7 months. The 1 and 2 year relapse rates after initiation of rituximab treatment were 0% and 3%, respectively. 25 patients discontinued regular rituximab treatment after a median number of six (4-12) doses. Six patients relapsed after discontinuing rituximab, and the 1 and 2 year relapse rates after the last regular rituximab treatment were 9% and 25%, respectively.

CONCLUSION

All patients with steroid-dependent nephrotic syndrome who received rituximab could discontinue glucocorticoid treatment with remission, and three-fourths of the patients remained in remission for > 2 years after discontinuing rituximab treatment.

Clinical advances in immunotherapy for immune-mediated glomerular diseases

BACKGROUND AND OBJECTIVE

Due to the suboptimal therapeutic efficacy and potential adverse effects associated with traditional immunosuppressive medications, there has been an increasing emphasis on the development and utilization of immunotherapies. This paper aims to provide clinicians with valuable insights for selecting appropriate therapeutic approaches and contribute to the development of novel immunotherapeutic drugs.

MAIN BODY

This paper categorizes the immunotherapeutic drugs that are used for the treatment of immune-mediated glomerular diseases into three groups: immunotherapies targeting antigen-presenting cells (anti-CD80), immunotherapies targeting T/B cells (anti-CD20, anti-CD22, BAFF and APRIL inhibitors, CD40-CD40L inhibitors, proteasome inhibitors, Syk inhibitors, and Btk inhibitors), and immunotherapies targeting the complement system (C5 inhibitors, C5a/C5aR inhibitors, C3 inhibitors, MASP2 inhibitors, factor B inhibitors, and factor D inhibitors). The article then provides a comprehensive overview of advances related to these immunotherapeutic drugs in clinical research.

CONCLUSION

Certain immunotherapeutic drugs, such as rituximab, belimumab, and eculizumab, have exhibited notable efficacy in treating specific immune-mediated glomerular diseases, thereby providing novel therapeutic approaches for patients. Nonetheless, the efficacy of numerous immunotherapeutic drugs remains to be substantiated.

Age and memory B cells at baseline are associated with risk of relapse and memory B-cell reappearance following anti-CD20 treatment in pediatric frequently-relapsing/steroid-dependent nephrotic syndrome

B-cell depleting anti-CD20 monoclonal antibodies, such as rituximab, have proven efficacy in children with frequently-relapsing/steroid-dependent nephrotic syndrome (FR/SDNS). However, drug-free remission is variable and specific baseline markers predictive of relapse after anti-CD20 treatment are still being defined. To clarify these, we performed a bicentric observational study in a large cohort of 102 children and young adults with FR/SDNS treated with anti-CD20 monoclonal antibodies (rituximab and ofatumumab). Sixty-two patients (60.8%) relapsed during a 24-month period (median [interquartile range] relapse-free survival, 14.4 months [7.9-24.0]). A lower risk of relapse was significantly associated with an older age (over 9.8 years, hazard ratio, 0.44; 95% confidence interval, 0.26-0.74) and a higher risk of relapse was significantly associated with higher circulating levels of memory B cells (1.14; 1.09-1.32) at time of anti-CD20 infusion, independent of time elapsed from onset, previous anti-CD20 treatment, type of administered anti-CD20 monoclonal antibodies, and previous or maintenance oral immunosuppression. Patients younger than 9.8 years at anti-CD20 infusion had a subsequent higher recovery of total, transitional, mature-naïve and memory B-cell subsets independent of previous anti-CD20 treatment and maintenance immunosuppression. Significantly, younger age and higher circulating levels of memory B cells at time of anti-CD20 infusion were also independently associated with the recovery of memory B cells by linear mixed-effects modelling. Thus, both younger age and higher circulating levels of memory B cells at time of infusion are independently associated with a higher risk of relapse and an earlier recovery of memory B cells following anti-CD20 treatment in children with FR/SDNS.

Repetitive administration of rituximab can achieve and maintain clinical remission in patients with MCD or FSGS

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are glomerulopathies associated with nephrotic syndrome. Primary forms of these diseases are treated with various regimes of immunosuppression. Frequently relapsing or glucocorticoid-dependent courses remain challenging. Here, a B-cell-depleting strategy with rituximab represents a salvage option although data are sparse in the adult population. In particular, there is limited evidence on the efficacy of restoring remission after initial successful treatment with rituximab and whether patients benefit from an individualized, relapse-based approach. We identified 13 patients who received multiple therapies with rituximab from the FOrMe-registry (NCT03949972), a nationwide registry for MCD and FSGS in Germany, or from the University Hospital of Cologne. Disease status, changes in serum creatinine, proteinuria, and time to relapse were evaluated. Relapse-free survival was compared to the patients' previous therapy regimens. Through all treatment cycles, an improvement of disease activity was shown leading to a complete remission in 72% and partial remission in 26% after 3 ([Formula: see text]0.001) and 6 months ([Formula: see text]0.001). Relapse-free survival increased from 4.5 months (95%-CI 3-10 months) to 21 months (95%-CI 16-32 months) ([Formula: see text]0.001) compared to previous immunosuppression regimens with no loss in estimated glomerular filtration over time (p = 0.53). Compared to continuous B-cell depletion, an individualized relapse-based approach led to a reduced rituximab exposure and significant cost savings. Relapse-based administration of rituximab in patients with MCD/FSGS with an initial good clinical response did not result in a decreased efficacy at a median follow-up duration of 110 months. Thus, reinduction therapies may provide an alternative to continuous B-cell-depletion and reduce the long-term side effects of continuous immunosuppression.

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.

Review of the Role of Rituximab in the Management of Adult Minimal Change Disease and Immune-Mediated Focal and Segmental Glomerulosclerosis

Background

Minimal change disease and primary FSGS are podocytopathies but are also immune-mediated diseases. Rituximab acts via multiple mechanisms by tilting the balance between autoreactive B and T cells in favor of regulatory B and T cells. The consequences are decreased production of cytokines, chemokines, and permeability factors by these cells. In the past decade, we have seen the discovery of autoantibodies mediating nephrotic syndrome (anti-annexin A2 antibody, anti-UCHL1 antibody, and anti-nephrin antibody), and rituximab decreases their production. Rituximab also binds to podocyte SMPDL3b and has direct podocyte actions.

Summary

Rituximab's role in managing these primary podocytopathies has been discussed in this brief review. Rituximab has been used extensively in children and adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, rituximab is not very promising in adult steroid-resistant nephrotic syndrome. Although ofatumumab would cause prolonged B-cell depletion and is fully humanized, it is unclear if it is superior to rituximab in preventing relapse of nephrotic syndrome.

Key Messages

Rituximab therapy can induce prolonged remission in adults with frequently relapsing and steroid-dependent nephrotic syndrome. However, no good data exist on using rituximab in steroid-resistant nephrotic syndrome.

Persistent SARS-CoV-2 Infection in a Patient with Nephrotic Syndrome under Rituximab Therapy: Successful Treatment with a Combination of Remdesivir and Monoclonal Antibodies

Rituximab is an effective treatment for frequently relapsing/steroid-dependent nephrotic syndrome, but there is concern about infections caused by humoral immunodeficiency. We herein report a case of prolonged (>7 weeks) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 24-year-old man with minimal change disease treated with rituximab developed SARS-CoV-2 infection. The clinical response to remdesivir was soon transiently abolished. Treatment with casirivimab and imdevimab (REGEN-COV) monoclonal antibodies in combination with remdesivir resulted in complete clearance of the infection. The REGEN-COV antibody cocktail may improve the outcome of SARS-CoV-2 infection in patients with humoral immunodeficiency.

Implications of rituximab pharmacokinetic and pharmacodynamic alterations in various immune-mediated glomerulopathies and potential anti-CD20 therapy alternatives

The specific B-cell depleting anti-CD20 monoclonal antibody rituximab (RTX) is effective in terms of the treatment of various immune-mediated glomerulopathies. The administration of RTX has been shown to be reliable and highly effective particularly in patients with ANCA-associated vasculitis, which is manifested predominantly with non-nephrotic proteinuria. Stable long-term B-cell depletion is usually readily attained in such patients using standard dosing regimens. However, in patients with nephrotic syndrome and non-selective proteinuria, the RTX pharmacokinetics is altered profoundly and RTX does not maintain high enough levels for a sufficiently long period, which may render RTX treatment ineffective. Since complement-derived cytotoxicity is one of the important modes of action of RTX, hypocomplementemia, frequently associated with systemic lupus erythematodes, may act to hamper the efficacy of RTX in the treatment of patients with lupus nephritis. This review provides a description of RTX pharmacokinetics and pharmacodynamics in several selected glomerulopathies, as well as the impact of proteinuria, anti-drug antibodies and other clinical variables on the clearance and volume of distribution of RTX. The impact of plasmapheresis and peritoneal dialysis on the clearance of RTX is also discussed in the paper. A review is provided of the potential association between pharmacokinetic and pharmacodynamic alterations in various kidney-affecting glomerular diseases, the sustainability of B-cell depletion and the clinical efficacy of RTX, with proposals for potential dosing implications. The role of therapeutic drug monitoring in treatment tailoring is also discussed, and various previously tested RTX dosing schedules are compared in terms of their clinical and laboratory treatment responses. Since alternative anti-CD20 molecules may prove effective in RTX unresponsive patients, their pharmacokinetics, pharmacodynamics and current role in the treatment of glomerulopathies are also mentioned.

Case report: Successful outcome of treatment using rituximab in an adult patient with refractory minimal change disease and β-thalassemia complicating autoimmune hemolytic anemia

Minimal change disease (MCD) is one of the common causes of idiopathic nephrotic syndrome (INS), accounting for 10-20% of INS in adults. Glucocorticoids are the most commonly used and effective drugs in the treatment of MCD, but there is still a proportion of adult patients with MCD who are characterized by glucocorticoid resistance, glucocorticoid dependence, and frequent relapse, which are defined as refractory nephrotic syndrome. Glucocorticoid combination with immunosuppressants is frequently used in patients with refractory nephrotic syndrome, and patients concerned about adverse effects caused by long-term high-dose glucocorticoid therapy. Recent studies have suggested that Rituximab (RTX), a chimeric monoclonal antibody targeted against the pan-B-cell marker CD20, combined with a small or medium dose of glucocorticoid has a beneficial effect with less adverse effects on adult patients with refractory MCD. β-thalassemia is an inherited hemoglobulin disorder caused by the mutation of genes that encode β-globin and results in ineffective erythropoiesis. We here report a case of an adult patient with refractory MCD complicated with β-thalassemia minor accompanied by autoimmune hemolytic anemia (AIHA). MCD relapsed several times despite treatment using glucocorticoid combined with or without different immunosuppressive agent regimens. The β-thalassemia minor was caused by heterozygosity for a 4-base deletion mutation [codons 41/42 (-TTCT) BETA0] of the β-globin gene. After the administration of RTX, MCD achieved clinical complete remission, and the anemia due to mild β-thalassemia recovered to normal as well. The disease situation remained stable during 36 months of follow-up. These findings suggest that RTX may contribute to the improvement of refractory MCD and anemia in β-thalassemia minor accompanied by AIHA.

CyTOF-Enabled Analysis Identifies Class-Switched B Cells as the Main Lymphocyte Subset Associated With Disease Relapse in Children With Idiopathic Nephrotic Syndrome

B cell depleting therapies permit immunosuppressive drug withdrawal and maintain remission in patients with frequently relapsing nephrotic syndrome (FRNS) or steroid–dependent nephrotic syndrome (SDNS), but lack of biomarkers for treatment failure. Post-depletion immune cell reconstitution may identify relapsing patients, but previous characterizations suffered from methodological limitations of flow cytometry. Time-of-flight mass cytometry (CyTOF) is a comprehensive analytic modality that simultaneously quantifies over 40 cellular markers. Herein, we report CyTOF-enabled immune cell comparisons over a 12-month period from 30 children with SDNS receiving B cell depleting therapy who either relapsed (n = 17) or remained stable (n = 13). Anti-CD20 treatment depleted all B cells subsets and CD20 depleting agent choice (rituximab vs ofatumumab) did not affect B cell subset recovery. Despite equal total numbers of B cells, 5 subsets of B cells were significantly higher in relapsing individuals; all identified subsets of B cells were class-switched. T cell subsets (including T follicular helper cells and regulatory T cells) and other major immune compartments were largely unaffected by B cell depletion, and similar between relapsing and stable children. In conclusion, CyTOF analysis of immune cells from anti-CD20 antibody treated patients identifies class-switched B cells as the main subset whose expansion associates with disease relapse. Our findings set the basis for future studies exploring how identified subsets can be used to monitor treatment response and improve our understanding of the pathogenesis of the disease.

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

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

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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

Rituximab Induces Complete Remission of Proteinuria in a Patient With Minimal Change Disease and No Detectable B Cells

Minimal change disease (MCD) is a common cause of nephrotic syndrome. Treatment with steroids is usually effective, but frequent relapses are therapeutic challenges. The anti-CD20 antibody rituximab has shown promising results for treatment of steroid-sensitive nephrotic syndrome. Since predictive biomarkers for treatment efficacy and the accurate rituximab dosage for effective induction of remission are unknown, measurement of CD19+ B cells in blood is often used as marker of successful B cell depletion and treatment efficacy. A male patient with relapsing MCD was successfully treated with rituximab, but developed relapse of proteinuria 1 year later, although no B cells were detectable in his blood. B and T cell populations in the patient's blood were analyzed before and after treatment with rituximab using FACS analysis. Rituximab binding to B and T cells were measured using Alexa Fluor 647 conjugated rituximab. We identified a population of CD20+ CD19- cells in the patient's blood, which consisted mostly of CD20+ CD3+ T cells. Despite the absence of B cells in the blood, the patient was again treated with rituximab. He developed complete remission of proteinuria and depletion of CD20+ T cells. In a control patient with relapsing MCD initial treatment with rituximab led to depletion of both CD20+ B and T cells. Rituximab induces remission of proteinuria in patients with MCD even if circulating B cells are absent. CD20+ T cells may play a role in the pathogenesis of MCD and might be a promising treatment target in patients with MCD.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

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

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

Background

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

Methods

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

Results

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

Conclusions

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Rituximab in maintaining remission in adults with podocytopathy

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

METHODS

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

PRIMARY OUTCOME

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

RESULTS

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

CONCLUSION

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Disseminated Intravascular Coagulation-like Reaction after Rituximab Infusion in a Patient with Nephrotic Syndrome

Several case series have suggested that rituximab is efficacious in adult patients with minimal change disease. We herein report a case of disseminated intravascular coagulation-like reaction after rituximab infusion in a patient with nephrotic syndrome. A 58-year-old Japanese man with minimal change disease diagnosed 15 years earlier was started on rituximab to prevent relapse of nephrotic syndrome when he presented to our clinic with low albuminemia, massive proteinuria, and leg edema. Eleven days after rituximab infusion, he presented with abdominal pain, appetite loss, and tarry stool. A laboratory examination revealed severe thrombocytopenia and coagulopathy, and upper gastrointestinal endoscopy revealed multiple hemorrhagic ulcers in his esophagus and stomach. The patient died two days later. Physicians should consider disseminated intravascular coagulation-like reaction when encountering cases with thrombocytopenia after rituximab infusion for any disease.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Update on the etiology, classification, and management of glomerular diseases

In this brief review, the reader will find a timely update regarding some of the most commonly encountered glomerular diseases. The review will include an update on the etiology with a focus on new genetic and molecular discoveries. New classifications will be elucidated, and management will be updated in broad strokes. Illustrative pathology slides will be used as appropriate. It is critical for the reader to realize from the outset that terminology such as focal segmental glomerulosclerosis and crescentic glomerulonephritis represent a pattern of injury rather than a specific disease. Whenever possible, the specific etiology and pathogenesis of a given pattern should be sought. It is also important to know that the same disease or mechanism can cause multiple patterns of injury, whereas the same pattern of injury can be the result of multiple disease or mechanisms.

Rituximab as a Preemptive Treatment to Prevent Recurrence of Primary Focal Segmental Glomerulosclerosis: A Novel Approach

OBJECTIVES

Primary idiopathic focal segmental glomerulo-sclerosis is a serious disease, frequently progressing to end-stage kidney failure. Management of recurrence after kidney transplant is challenging despite multiple proposed therapeutic approaches. Available treatment for focal segmental glomeru-losclerosis recurrence is plasma exchange, intravenous cyclosporine, and rituximab. In this study, we investigated kidney transplant recipients with focal segmental glomerulosclerosis who were at high risk for recurrence. Patients were given preemptive rituximab at day 0 posttransplant.

MATERIALS AND METHODS

Between January 2013 and June 2017, our center had 8 patients with primary focal segmental glomerulosclerosis at high risk for recurrence who were scheduled for kidney transplant. These patients received a single rituximab infusion of 375 mg/m2 on day 0 posttransplant. Recurrence of focal segmental glomerulosclerosis posttransplant was defined as repeated proteinuria > 2 g/day, without evidence of clinical or biopsy-proven rejection.

RESULTS

Follow-up showed that none of our patients had immediate posttransplant proteinuria. Only 1 patient developed proteinuria at almost 4 months posttransplant. Mean follow-up duration was 8 months. With regard to complications, 2 patients had serious bacterial infections and 1 patient had cytomegalovirus infection.

CONCLUSIONS

Rituximab at day 0 posttransplant may be used safely to prevent focal segmental glomeru-losclerosis recurrence in the graft in the early posttransplant period. However, longer follow-up studies with larger series are needed.

Outcomes of Older Patients (≥60 years) with New-Onset Idiopathic Nephrotic Syndrome Receiving Immunosuppressive Regimen: A Multicentre Study of 116 Patients

Because of its rarity, renal presentation and outcomes of idiopathic nephrotic syndrome (INS; minimal changes disease or focal and segmental glomerulosclerosis) has poorly been described in elderly patients, precluding an individualized therapy procedure. Whether immunosuppressive regimens formerly designed in children and young adults are safe and efficient in elderly remains elusive. In a large multicentric retrospective study that included 116 patients with INS and onset ≥ 60 years of age, we showed that cumulative incidence of renal response was 95% after frontline therapy, with an age-dependent median time-to-response (60 days before 70 years of age at the onset vs. 120 days after; p = 0.03). Cumulative incidence of relapse was 90% at 7 years, with relapse occurring continuously over time. After a median follow-up of 34 months (IQR (12; 57)), 7 patients had died (6%) and 5 reached end-stage renal disease. Complications were highly prevalent: diabetes mellitus (23.3%), hypertension (24.1%), infection requiring hospitalization (21.6%) and acute kidney injury (9.5%). Thus, in older patients with INS and receiving steroids, renal response is delayed and relapse is the rule. Alternative immunosuppressive regimens, including B-cells depleting agents as frontline therapy, should be tested in this subset of patients to improve the mid- to long-term outcomes.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Adverse events linked with the use of chimeric and humanized anti-CD20 antibodies in children with idiopathic nephrotic syndrome

AIMS

Anti-CD20 antibodies are increasingly being used to treat idiopathic nephrotic syndrome (INS) in children. While they may allow steroid and calcineurin inhibitor withdrawal, repeated infusions of anti-CD20 antibodies are often required to maintain remission. Data on their potential toxicity in INS are needed, to consider repeated infusions.

METHODS

We investigated the side effects associated with the use of rituximab (a chimeric antibody; 130 patients) and ofatumumab (a humanized antibody; 37 patients) in children with INS (steroid-dependent and steroid/calcineurin inhibitor-dependent disease) treated at a national referral centre over a 9-year period (400 treatments; follow-up 1-9 years).

RESULTS

Infusion reactions were mainly absent in children with steroid-dependent disease. Rash, dyspnoea, fever, cough and itchy throat (5% and 18% following rituximab and ofatumumab infusion, respectively) were resolved by using premedication with salbutamol. Other short-term reactions (up to 3 months), including arthritis (2%) and lung injury (1%), were more common with rituximab. Infections were observed 3-9 months following infusion, were similarly common in the two groups and resolved with targeted therapies [antibiotic, fluconazole, immunoglobulins (Igs), etc.]. The number of circulating CD19/20 cells fell to 0 at month 1 and were reconstituted at month 3; circulating IgG antibodies remained within the normal range for 1 year. Tetanus and hepatitis B virus immunization was not modified by either treatment; Epstein-Barr virus and John Cunningham virus activation markers were occasionally observed.

CONCLUSION

Overall, the toxicity of anti-CD20 monoclonal antibodies was limited to post-infusion side effects in children with more complex disease. The relatively safe profile of anti-CD20 antibodies supports their use as steroid-sparing agents in children with INS.

Children with Steroid-Resistant Nephrotic Syndrome: A Single -Center Experience

Background

Nephrotic syndrome (NS) is one of the most frequent glomerular diseases among children. While most of the children with primary NS respond to steroid treatment, 10 to 20% of the patients are steroid-resistant, and the best therapy for such cases has never been defined.

Objective

The present study aimed to evaluate steroid-resistant nephrotic syndrome (SRNS) patients.

Materials and methods

Our research included 50 children (56% female and 44% male) with NS. NS was defined as the presence of edema, massive proteinuria, hypoalbuminemia and hyperlipidemia. Patients with NS were treated according to international protocol. SRNS was diagnosed in patients with idiopathic NS based on lack of complete remission despite treatment with steroids. Renal biopsy was performed in 22 patients with SRNS at the Pediatric Clinic II of the University Clinical Center in Sarajevo (UCCS). Histopathologic analyzes of renal biopsy were performed at the Department of Pathology, University Clinical Center in Tuzla (UCCT). Patients with SRNS, after kidney biopsy were treated with nonsteroidal immunosuppressant's.

Results

Eight (36.4%) of the 22 patients who had undergone renal biopsies had minimal change disease (MCNS) and seven (31.8%) had focal segmental glomerulosclerosis (FSGS). The immunosuppressive drugs used in SRNS were Cyclosporine (CsA), Cyclophosphamide (CYC), Mycophenolat mofetil (MMF) and Rituximab (RTX). Three patients (13.6%) did not respond to any treatment and had developed end - stage renal disease (ESRD).

Conclusion

With current treatments, some children will ultimately achieve a sustained remission with one of the second line or third line of the proposed drugs. Patients with refractory NS will go to progression towards ESRD. The rapid development of molecular genetics will give a new contribution to the pathogenesis and treatment of this disease.

Efficacy of mycophenolate treatment in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome

BACKGROUND

This study assessed the efficacy of therapy with mycophenolate (MF) and reduced doses of steroids in adults with steroid-dependent/frequently relapsing idiopathic nephrotic syndrome (SD/FR-INS).

METHODS

Twenty-nine nephrotic patients (including 16 males and 13 females; mean age: 40 years, range: 18-74) were treated. Starting doses of MF were 2000 mg/day for mofetil MF (1500 mg/day in one patient) or 1440 mg/day for sodium MF. The initial prednisone (PDN) dose was 10 mg/day in 14 patients, 5 mg/day in two patients and no steroids in one patient. In the remaining 12 patients, moderate initial doses of PDN were administered (mean: 23.7 mg/day, range: 15-40), tapering to 10 mg/day after 1 month.

RESULTS

Nephrotic syndrome remission was achieved in 27/29 cases (93.1%) (25 complete, 2 partial). Two patients showed resistance to the prescribed schedule. The first cycle of MF therapy was concluded in 20 patients after a mean (range) of 16.9 months (12-49). Maintenance of remission was observed in 11 of these 20 cases (55%) after a mean follow-up of 32.8 months (12-108). In nine patients with nephrotic syndrome relapse after tapering of MF (MF dependency), the same MF-PDN schedule was restarted, leading again to remission in all nine. The remaining seven MF-sensitive patients are still receiving their first therapeutic cycle. To date, the mean time under therapy in the 27 MF-sensitive patients is 38 months (4-216). Regarding complications, only minor digestive disorders and a slight decrease in blood haemoglobin levels were observed in a few patients.

CONCLUSIONS

MF plus reduced doses of PDN is an effective and well-tolerated therapy for adult SD/FR-INS. Though MF dependence is observed, its low toxicity could allow long periods of therapy if it is required to maintain nephrotic syndrome remission.

Rituximab for Recurrence of Primary Focal Segmental Glomerulosclerosis After Kidney Transplantation: Clinical Outcomes

BACKGROUND

Rituximab has shown encouraging results for the treatment of kidney transplantation recipients with focal segmental glomerulosclerosis (FSGS) recurrence. However, the correct, opportune, and safe use of rituximab for this indication remains to be determined.

METHODS

This multicenter retrospective study reports on 19 new cases aged 35 (15-66) years who developed FSGS recurrence at 12 (1.5-27) days posttransplantation. Initial treatment consisted of plasma exchanges (PE), high doses of calcineurin inhibitors, and steroids. Rituximab was introduced either immediately (N = 6) or after failure of the initial treatment (N = 10) or failed attempted weaning from PE (N = 3).

RESULTS

Overall, we observed 9 of 19 complete remissions and 3 of 19 partial remissions. Estimated glomerular filtration rates (Modification of Diet in Renal Disease 4) were significantly higher in the responding patients than in nonresponding patients at month (M)12, M36, and M60. Overall, kidney survival at 5 years was 77.4% (95% range, 41.9-92.7). The 5-year graft survival rates in the responding patients and the nonresponding patients were 100% and 36.5%, respectively (P = 0.01). A further course of rituximab was required for 4 patients as a result of FSGS relapse, with good results. During the first year after renal transplantation, 14 patients developed severe infections (16 bacterial, 4 viral, 1 parasitic).

CONCLUSIONS

In kidney transplantation recipients with recurrent FSGS, rituximab therapy may be a recommended treatment for cases that have failed either the initial treatment or weaning from PE.

Recent Treatment Advances and New Trials in Adult Nephrotic Syndrome

The etiology of nephrotic syndrome is complex and ranges from primary glomerulonephritis to secondary forms. Patients with nephrotic syndrome often need immunosuppressive treatment with its side effects and may progress to end stage renal disease. This review focuses on recent advances in the treatment of primary causes of nephrotic syndrome (idiopathic membranous nephropathy (iMN), minimal change disease (MCD), and focal segmental glomerulosclerosis (FSGS)) since the publication of the KDIGO guidelines in 2012. Current treatment recommendations are mostly based on randomized controlled trials (RCTs) in children, small RCTs, or case series in adults. Recently, only a few new RCTs have been published, such as the Gemritux trial evaluating rituximab treatment versus supportive antiproteinuric and antihypertensive therapy in iMN. Many RCTs are ongoing for iMN, MCD, and FSGS that will provide further information on the effectiveness of different treatment options for the causative disease. In addition to reviewing recent clinical studies, we provide insight into potential new targets for the treatment of nephrotic syndrome from recent basic science publications.

The Evolving Role of Rituximab in Adult Minimal Change Glomerulopathy

BACKGROUND

Minimal-change glomerulopathy is defined histologically by the presence of normal glomeruli on light microscopy and diffuse podocyte effacement on electron microscopy. Although effective in children, corticosteroid treatment in adults is more variable and time to response can be prolonged. Data to support rituximab use in adults with corticosteroid-dependent or resistant minimal-change glomerulopathy are limited. Here, we describe the clinical course of adults with corticosteroid-dependent or -resistant minimal-change glomerulopathy who received rituximab.

METHODS

Demographic and clinical data were collected and analyzed from all adult patients with native kidney, biopsy-proven, minimal-change glomerulopathy who were administered rituximab between 2009 and 2014 and cared for at the UNC Kidney Center.

RESULTS

Ten patients with corticosteroid-resistant (n = 5) or corticosteroid-dependent (n = 5) idiopathic minimal-change glomerulopathy were treated with rituximab between 2009 and 2014. Rituximab treatment induced remission in all 10 patients with a median time to remission of 2 months. The median time from rituximab to corticosteroid discontinuation was 3.5 months. The median remission time was 29 months and follow-up time was 39.5 months. No serious adverse events attributable to rituximab were observed.

CONCLUSION

Rituximab induced remission in all patients with corticosteroid-dependent or -resistant minimal-change glomerulopathy, and may hold great therapeutic potential with good efficacy and minimal toxicity. Mounting evidence implies that a well-conducted randomized controlled clinical trial using rituximab in adults with minimal-change glomerulopathy in both corticosteroid-resistant and corticosteroid-dependent patients is warranted.

Rituximab in Minimal Change Disease: Mechanisms of Action and Hypotheses for Future Studies

Treatment with rituximab, a monoclonal antibody against the B-lymphocyte surface protein CD20, leads to the depletion of B cells. Recently, rituximab was reported to effectively prevent relapses of glucocorticoid-dependent or frequently relapsing minimal change disease (MCD). MCD is thought to be T-cell mediated; how rituximab controls MCD is not understood. In this review, we summarize key clinical studies demonstrating the efficacy of rituximab in idiopathic nephrotic syndrome, mainly MCD. We then discuss immunological features of this disease and potential mechanisms of action of rituximab in its treatment based on what is known about the therapeutic action of rituximab in other immune-mediated disorders. We believe that studies aimed at understanding the mechanisms of action of rituximab in MCD will provide a novel approach to resolve the elusive immune pathophysiology of MCD.

Effective treatment with rituximab for the maintenance of remission in frequently relapsing minimal change disease

AIM

Treatment of frequently relapsing or steroid-dependent minimal change disease (MCD) in children and adults remains challenging. Glucocorticoids and/or other immunosuppressive agents are the mainstay of treatment, but patients often experience toxicity from prolonged exposure and may either become treatment dependent and/or resistant. Increasing evidence suggests that rituximab (RTX) can be a useful alternative to standard immunosuppression and allow withdrawal of maintenance immunosuppressants; however, data on optimal treatment regimens, long-term efficacy and safety are still limited.

METHODS

We undertook a prospective study of RTX to allow immunosuppression minimization in 15 young adults with frequently relapsing or steroid-dependent, biopsy-proven MCD. All patients were in remission at the start of treatment and on a calcineurin inhibitor. Two doses of RTX (1 gr) were given 6 months apart. A subset of patients also received an additional dose 12 months later, in order to examine the benefit of re-treatment. Biochemical and clinical parameters were monitored over an extended follow-up period of up to 43 months.

RESULTS

Median steroid-free survival after RTX was 25 months (range 4-34). Mean relapse frequency decreased from 2.60 ± 0.28 to 0.4 ± 0.19 (P < 0.001) after RTX. Seven relapses occurred, five of which (71%) when CD19 counts were greater than 100 µ. Immunoglobulin levels remained unchanged, and no major side effects were observed throughout the follow-up period.

CONCLUSIONS

Rituximab therapy is effective at maintaining prolonged steroid-free remission and reducing relapse frequency in this group of patients. Our study lends further support for the role of RTX in the treatment of patients with frequently relapsing or steroid-dependent MCD.

The efficacy of rituximab in adult frequently relapsing minimal change disease

Background

Corticosteroids are the basis of treatment for nephrotic syndrome due to minimal change disease (MCD), but 25% of patients have frequently relapsing nephrotic syndrome (FRNS) and 30% become steroid dependent. Prolonged use of conventional immunosuppressants causes significant toxicity. Rituximab (RTX) is now included in guidelines for childhood MCD. Evidence for use in adult MCD is limited. We describe a single-centre experience of RTX use in adult MCD.

Methods

Outcomes of all adult MCD patients treated with RTX for FRNS between 2008 and 2015 were retrospectively analysed.

Results

Thirteen patients received RTX; 11/13 had childhood-onset MCD. All had FRNS and 10 were steroid dependent. Eleven patients experienced one or more major treatment side effect from conventional therapy. At the time of RTX treatment, six patients were relapsing. All entered remission after RTX. The median length of follow-up after the first RTX treatment was 20 months (range 6–85). After RTX, the rate of relapse was reduced from 4 to 0.4/year (Wilcoxon signed rank P ≤ 0.05). Seven patients relapsed after RTX after a median of 10 months (range 1–11). All seven relapsing patients were successfully re-treated with RTX and none developed RTX-resistant nephrosis. The median number of courses of RTX per patient was 1 (range 1–5). The number of additional immunosuppressants, steroid dependency and antihypertensive agents were also reduced. At the last follow-up, two patients remained on low-dose steroids. No RTX-related adverse events were observed.

Conclusion

RTX is safe and effective in adults with FRNS due to MCD. The median rate of relapse is significantly reduced following RTX treatment and additional immunosuppressant exposure is minimized.

Rituximab use in adult primary glomerulopathy: where is the evidence?

Rituximab is a chimeric anti-CD20 antibody that results in depletion of B-cell lymphocytes. It is currently used in the treatment of a variety of autoimmune diseases, in addition to CD20-positive lymphomas. The use of rituximab in the treatment of the adult primary glomerular diseases has emerged recently, although not yet established as first-line therapy in international guidelines. In patients with steroid-dependent minimal change disease or frequently relapsing disease, and in patients with idiopathic membranous nephropathy (IMN), several retrospective and prospective studies support the use of rituximab to induce remission, whereas in idiopathic focal and segmental glomerulosclerosis (FSGS), the use of rituximab has resulted in variable results. Evidence is still lacking for the use of rituximab in patients with immunoglobulin A nephropathy (IgAN) and idiopathic membranoproliferative glomerulonephritis (MPGN), as only few reports used rituximab in these two entities. Randomized controlled trials (RCTs) are warranted and clearly needed to establish the definitive role of rituximab in the management of steroid-dependent and frequently relapsing minimal change disease, IMN, both as first-line and second-line treatment, and in MPGN. We await the results of an ongoing RCT of rituximab use in IgAN. Although current evidence for the use of rituximab in patients with idiopathic FSGS is poor, more RCTs are needed to clarify its role, if any, in the management of steroid-resistant or steroid-dependent FSGS.

B Cell Reconstitution after Rituximab Treatment in Idiopathic Nephrotic Syndrome

The pathogenesis of nephrotic syndrome is unclear. However, the efficacy of rituximab, a B cell-depleting antibody, in nephrotic syndrome suggests a pathogenic role of B cells. In this retrospective study, we determined by flow cytometry levels of B and T cell subpopulations before and after rituximab infusion in 28 pediatric patients with frequently relapsing or steroid-dependent nephrotic syndrome. At baseline, patients had lower median percentages of transitional and mature B cells than age-matched healthy controls (P<0.001). Rituximab induced full depletion of B cells (<1% of lymphocytes). At 1 year, most patients exhibited complete total and mature B cell recovery, whereas memory B cell subsets remained significantly depleted. Total T cell concentration did not change with rituximab, whereas the CD4(+)/CD8(+) T cell ratio tended to increase. Fourteen patients relapsed within 24 months, with a median follow-up of 11.2 months (interquartile range, 8-17.7 months). We observed no difference at baseline between nonrelapsing and relapsing patients in several clinical parameters and cell subset concentrations. Reconstitution of all memory B cell subpopulations, number of immunosuppressive drugs, and dose of tacrolimus during the last 4 months of follow-up were predictive of relapse in univariate Cox regression analysis. However, only delayed reconstitution of switched memory B cells, independent of immunosuppressive treatment, was protective against relapse in multivariate (P<0.01) and receiver operator characteristic (P<0.01 for percentage of lymphocytes; P=0.02 for absolute count) analyses. Evaluation of switched memory B cell recovery after rituximab may be useful for predicting relapse in patients with nephrotic syndrome.

Minimal Change Nephrotic Syndrome Which Was Most Likely Caused by Chronic Sinusitis

A 33-year-old Japanese man was admitted with severe edema, and a renal biopsy confirmed minimal change nephrotic syndrome (MCNS). CT revealed his severe chronic sinusitis, and he first received antimicrobial therapy, which resulted in decreased proteinuria. The surgical operation for sinusitis resulted in the complete disappearance of proteinuria without corticosteroid or immunosuppressant therapy within one week. MCNS may be triggered by infection, but there are no previously reported cases of MCNS that is completely remitted by infection control alone. Therefore, we herein report the first case of MCNS that attained complete remission following therapy for chronic sinusitis alone, which suggests a strong etiology of chronic sinusitis for MCNS.

The Evidence-Based Approach to Adult-Onset Idiopathic Nephrotic Syndrome

Adult-onset nephrotic syndrome (NS) differs from its pediatric counterpart in several important ways. Most importantly, NS in adults is more etiologically heterogeneous compared to children, and thus treatment approaches rely heavily on the histological diagnosis provided by renal biopsy. The evidence-based approach to treatment of adult NS has been critically examined by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines in glomerulonephritis, published in 2012. Here, we examine the strengths and limits of those guidelines and review recent work that expands the evidence-based approach.