Unexpected efficacy of rituximab in multirelapsing minimal change nephrotic syndrome in the adult: first case report and pathophysiological considerations

Impact of Thyroid Cancer Treatment on Renal Function: A Relevant Issue to Be Addressed

Thyroid cancers require complex and heterogeneous therapies with different impacts on renal function. In our systematic literature review, we analyzed several aspects: renal function assessment, the impact of radiotherapy and thyroid surgery on kidney functioning, and mechanisms of nephrotoxicity of different chemotherapy, targeted and immunologic drugs. Our study revealed that the renal impact of thyroid cancer therapy can be a limiting factor in all radiotherapy, surgery, and pharmacological approaches. It is advisable to conduct a careful nephrological follow-up imposing the application of body surface based estimated Glomerular Filtration Rate (eGFR) formulas for the purpose of an early diagnosis and treatment of renal failure, guaranteeing the therapy continuation to thyroid cancer patients.

Nephrotoxicity in advanced thyroid cancer treated with tyrosine kinase inhibitors: An update

Over the past decade, the prognosis of advanced thyroid cancer (TC) patients has dramatically improved thanks to the introduction of tyrosine kinase inhibitors (TKIs). Despite their effectiveness, these drugs are burdened with several side effects that can negatively affect quality of life and compromise therapy continuation. Among renal adverse events (RAEs), proteinuria is the most frequently reported in clinical trials and real-life experiences, especially during treatment with lenvatinib or cabozantinib. This peculiar toxicity is commonly associated with targeted therapies with anti-angiogenic activity, even if the mechanisms underlying its onset and progression are not entirely clear. RAEs should be early recognized and properly managed to avoid renal function worsening and life-threatening consequences. Aiming at providing a comprehensive summary that can help clinicians to identify and manage TKIs-related RAEs in TC patients, we reviewed the current evidence about this topic, from pathogenesis and potential risk factors to diagnosis and treatment.

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.

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.

Clinical Response and Pattern of B cell Suppression with Single Low Dose Rituximab in Nephrology

Background

There is no consensus regarding dose and frequency of rituximab in nephrology with extrapolation of doses used in treating lymphoproliferative disorders. There are no guidelines on targeting initial and subsequent doses on the basis of CD19⁺ B cells.

Methods

Initially, 100 mg rituximab was given to 42 adults with steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN), and high-immunologic-risk kidney transplantation. Absolute and percentage levels of CD19 B cells and clinical status were assessed at baseline, days 30, 90, and 180, and at 1 year. Subsequent doses of rituximab were on the basis of CD19 B cell reconstitution and clinical response.

Results

CD19 B cell percentage decreased from 16.3 ± 7.6 to 0.3 ± 0.3 (P≤0.001), 1.9 ± 1.7 (P≤0.001), and 4.0 ± 4.5 (P=0.005) by 30, 90, and 180 days, respectively. Suppression of CD19 B cell count below 1% at days 30, 90, and 180 was seen in 40 of 42 (95.2%), 18 of 42 (42.9%), and 7 of 42 (16.7%) patients, respectively. Of 30 with SDNS and FRNS followed up for 1 year, 29 (96.7%) went into remission at day 30. Remission was sustained in 23 (76.6%) at day 180 and 21 (70%) at 1 year. There was a significant decrease (P<0.001) in the dose of steroids needed to maintain remission at 180 days after rituximab (0.27 ± 0.02 mg/kg to 0.02 ± 0.00 mg/kg). CD19 B cell percentage at 90 days correlated with relapse (P=0.001; odds ratio 1.42; 95% confidence interval, 1.25 to 2.57). Eighteen (60%) required an additional dose. Of five with MN, four achieved remission by 6 months, which was sustained in three by 1 year. Of the seven kidney transplant recipients, two had antibody-mediated rejections, although CD19 B cells were suppressed even at 1 year.

Conclusions

Low-dose rituximab induces sustained depletion of CD19 B cells for up to 90 days. Its role in preventing relapses in SDNS, FRNS, MN, and rejection needs further study.

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.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.

Treatment patterns and steroid dose for adult minimal change disease relapses: A retrospective cohort study

Background

In patients with adult minimal change disease (MCD), proteinuria relapse is a problem to solve. However, the optimal relapse treatment regimen remains unclear regarding steroid dose. We described the treatment pattern of adult MCD patients and evaluated the appropriate steroid dose for relapse treatment.

Methods

This retrospective multicenter cohort study included 192 patients with adult biopsy-proven MCD from 14 hospitals in Japan. The prescription pattern of immunosuppressive drugs in relapse was reviewed. To assess the association between steroid dose used for relapse and subsequent outcomes, data of patients with tapered prednisolone (PSL) dosage to <10 mg/day before the first relapse in whom the dose was subsequently increased to ≥10 mg/day were extracted and assigned to the High-PSL or Low-PSL groups, based on the median dose of 20 mg/day. Multivariate Cox proportional hazard model and propensity score analysis with multiple imputations were conducted to compare their clinical course.

Results

During a median observation period of 37.6 months, 186/192 (96.9%) patients achieved complete remission (CR) and 100 (52.1%) relapsed. The median urinary protein level at the first relapse was 3.12 g/gCr or g/day. The proportion of non-steroidal immunosuppressant use increased with relapses; cyclosporine was the most common. No significant differences were found in the second relapse, frequent relapses, or adverse events between High-PSL (n = 34) and Low-PSL (n = 36) groups. A multivariate Cox proportional hazard model revealed that the hazard ratios adjusted with propensity score for the second relapse were 0.94 (High-PSL vs. Low-PSL; 95% confidence interval, 0.42–2.10; P = 0.88) and 0.82 (PSL dose per 10 mg/day; 95% confidence interval, 0.58–1.16; P = 0.25).

Conclusions

Among patients in CR with PSL dose <10 mg/day, higher steroid dose (PSL >20 mg/day) was not associated with favorable outcomes after the first relapse as compared to lower dose (10–20 mg/day).

Rituximab in steroid-sensitive nephrotic syndrome: lessons from clinical trials

Idiopathic nephrotic syndrome is the most common chronic glomerular disease in children. A total of 80-90% of patients with childhood idiopathic nephrotic syndrome achieve remission with steroid therapy [steroid-sensitive nephrotic syndrome (SSNS)]. However, approximately 50% of children with SSNS develop frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS). Children with FRNS or SDNS are usually treated with immunosuppressive agents, but 10-20% of children receiving immunosuppressive agents still show frequent relapses or steroid dependence during or after treatment, defined as complicated FRNS or SDNS. Rituximab, a chimeric anti-CD20 monoclonal antibody that was originally developed to treat patients with B-cell non-Hodgkin's lymphoma, is currently used for treating SSNS. In this review we highlight recent studies, mainly randomized controlled trials of rituximab for SSNS, including complicated and uncomplicated forms of FRNS or SDNS in children. We also discuss the effects of these studies on the management of patients suffering from these conditions.

Rituximab in children with steroid-dependent nephrotic syndrome: experience of a tertiary center and review of the literature

OBJECTIVES

Rituximab (RTX) is a new treatment option in children with difficult-to-treat steroid-dependent nephrotic syndrome (SDNS). We evaluated the experience of our tertiary center and reviewed the current literature.

METHODS

This is a retrospective single-center study evaluating the efficacy and safety of RTX in children with difficult-to-treat SDNS. Age at diagnosis, type and duration of immunosuppression, age at administration, dose of RTX, possible adverse events, number of relapses, duration of remission, and B-cell count after administration of RTX were analyzed.

RESULTS

Nine children with a median age at diagnosis of nephrotic syndrome of 4.75 (range 1.33-11.33) years and a median age at administration of RTX of 16.08 (range 3.33-19.25) years were included. Before administration of RTX they had a median number of relapses per year of 1.70 (range 0.82-4.80). At last follow-up (median 2.75 years, range 0.58-3.92), a reduction in the number of relapses per year to 0.26 (range 0-2.18) was noted, despite cessation or lowering the dose of immunosuppressive therapy. Four patients achieved complete remission after the first administration of RTX, four more patients after subsequent doses of RTX. No severe adverse events were noted.

CONCLUSION

RTX was an effective and safe therapeutic option in our cohort of children with difficult-to-treat SDNS, resulting in a significant reduction of yearly relapses in the absence of severe adverse events and facilitating the reduction of other immunosuppressive medication.

Single low-dose rituximab for the treatment of steroid-resistant nephrotic syndrome with acute kidney injury

The efficacy of rituximab for kidney disease, such as frequent relapsing nephrotic syndrome, has been reported recently. Herein, we report a case of a patient with acute kidney injury that was steroid-resistant nephrotic syndrome who responded to a single administration of low-dose rituximab. An 86-year-old Japanese woman with hypertension presented with severe peripheral edema within several days after onset. Due to the patient's age, renal biopsy was not performed, nephrotic syndrome was diagnosed and prednisolone was administered at 40 mg/day on the day after admission. However, anuria developed and hemodialysis was inevitably initiated on the 5th hospital day. The renal function did not recover, and the general condition gradually became aggravated. On the 50th hospital day, 100 mg rituximab was administered, which led to immediate depletion of CD20-positive cells. The urine volume gradually increased from 2-3 weeks after the rituximab administration, and the renal function recovered slightly. After 5 weeks, it became possible to wean the patient from dialysis, which had been applied for 3 months. Rituximab might be an option for the treatment of acute kidney injury due to steroid-resistant nephrotic syndrome.

Cost-Effectiveness of Administering Rituximab for Steroid-Dependent Nephrotic Syndrome and Frequently Relapsing Nephrotic Syndrome: A Preliminary Study in Japan

With regard to the use of rituximab for patients with steroid-dependent nephrotic syndrome and frequently relapsing nephrotic syndrome, not only has the regimen not been clinically verified but also there is a lack of health economics evidence. Therefore, we conducted a prospective clinical study on 30 patients before (with steroids and immunosuppressants) and after introducing rituximab therapy. Relapse rates and total invoiced medical expenses were selected as the primary endpoints for treatment effectiveness and treatment costs, respectively. As secondary endpoints, cost-effectiveness was compared before and after administering rituximab in relation to previous pharmacotherapy. The observation period was 24 months before and after the initiation of rituximab. We showed that there was a statistically significant improvement in the relapse rate from a mean of 4.30 events before administration to a mean of 0.27 events after administration and that there was a significantly better prognosis in the cumulative avoidance of relapse rate by Kaplan-Meier analysis (p < 0.01). Finally, the total medical costs decreased from 2,923 USD to 1,280 USD per month, and the pre-post cost-effectiveness was confirmed as dominant. We, therefore, conclude that treatment with rituximab was possibly superior to previous pharmacological treatments from a health economics perspective.

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.

Biologic agents in the treatment of glomerulonephritides

Current immunosuppression strategies in the treatment of glomerulonephritides remain unsatisfactory, especially in glomerular diseases that are frequently relapsing or are resistant to treatment. Toxicities associated with the use of drugs with non-specific targets for the immune response result in treatment non-compliance, and increase morbidity and mortality in these patients. Advances in our understanding of the immunopathogenesis of glomerulonephritis and the availability of biologics have led to their successful use in the treatment of immune-mediated glomerular diseases. Biologics are usually very large complex molecules, often produced using recombinant DNA technology and manufactured in a living system such as a microorganism, or plant or animal cells. They are novel agents that can target specific immune cell types, cytokines or immune pathways involved in the pathogenesis of these disorders. It is attractive to consider that, given their specific mode of action, these agents can potentially offer a more directed and effective immunosuppression, with side-effect profiles that are much more desirable. However, there have been few randomized controlled trials comparing biologic agents to conventional immunosuppression, and in many of these studies the side-effect profiles have been disappointingly similar. In this review, we will examine the rationale, efficacy and safety of some commonly used biologics in the treatment of primary and secondary glomerulonephritides. We will also discuss some of the key challenges that may be encountered with the use of biologics in treating glomerulonephritis in the future.

A series of patients with minimal change nephropathy treated with rituximab during adolescence and adulthood

Background

The treatment of immune suppression dependent minimal change nephropathy (MCN) can be challenging and frequently leads to serious complications. In paediatric patients, successful treatment with rituximab is described in steroid-dependent MCN. There is limited information about the potential efficacy of rituximab for the treatment of MCN in adults and adolescence. We describe our experience with rituximab in adolescent and adult patients with immune suppression dependent MCN.

Results

Ten adolescents and adults with immune suppression dependent MCN and therapy related complications were treated with rituximab. At a mean age of 26 years, about 10.5 years after first presentation, they received two doses of rituximab (375 mg/m²). Maintenance immunosuppressive medication was stopped. After a mean follow-up of 43 months, three patients had four relapses. Three relapses were successfully retreated with rituximab again, after induction therapy with 60 mg prednisone per day. Rituximab was well tolerated and no infectious complications were recorded.

Conclusion

Treatment with rituximab induces a long-term remission of immune suppression dependent MCN in adolescents and adults. A timely treatment with rituximab could be considered to limit side effects of immunosuppressive medication.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1255-0) contains supplementary material, which is available to authorized users.

Long-term prognosis of adult patients with steroid-dependent minimal change nephrotic syndrome following rituximab treatment

This study was to evaluate the long-term efficacy and safety of a single-dose rituximab regimen rituximab treatment in adult patients with steroid-dependent minimal change nephrotic syndrome (MCNS). We conducted a prospective cohort study with historical controls to evaluate the effect of single-dose infusions of rituximab at 375 mg/m2 BSA per dose administered at intervals of 6 months for a period of 24 months. At the end of the 24-month period, the patients were divided into the treatment continuation (n = 20) and treatment discontinuation (n = 5) groups according to their intention to continue/discontinue the treatment. A significant reduction in the total number of relapses was observed during the 24-month period after the first rituximab infusion as compared with that during the 24-month period before the first rituximab infusion (108 vs. 8, P < 0.001). Complete remission was induced/maintained in all patients from 12 to 24 months after the first rituximab infusion. In regard to the clinical course after 24 months, 4 of the 20 patients in the treatment continuation group discontinued the rituximab treatment after the fifth infusion and 2 patients discontinued the treatment after the sixth infusion. However, complete remission was maintained in all the 20 patients of this group during the 12-month observation period after the first four single-dose rituximab infusions. On the other hand, 1 of the 5 patients in the treatment discontinuation group developed relapse during the observation period after the first four rituximab infusions, and the rituximab treatment was resumed. In our trial, rituximab therapy was associated with maintenance of complete remission. Complete remission was maintained even in most of the patients who showed B-cell repletion after discontinuation of rituximab therapy. Thus, rituximab may be considered as a radical therapeutic agent for patients with steroid-dependent MCNS.

Sustained complete remission of steroid- and cyclophosphamide-resistant minimal-change disease with a single course of rituximab therapy

We report a case of steroid- and cyclophosphamide-resistant nephrotic syndrome secondary to minimal-change disease occurring in an otherwise healthy 19-year-old female, responding rapidly to two doses of rituximab therapy. Complete disease remission has been sustained up to last follow-up (32 months) despite CD19 recovery. Literature review suggests emerging evidence that rituximab may have a role to play in recurrent and/or refractory minimal-change disease.

Rituximab in steroid-dependent or frequently relapsing idiopathic nephrotic syndrome

The outcome of steroid-dependent or frequently relapsing nephrotic syndrome of minimal change disease (MCD), mesangial proliferative GN (MesGN), or FSGS may be poor and with major treatment toxicity. This academic, multicenter, off-on trial (ClinicalTrials.gov #NCT00981838) primarily evaluated the effects of rituximab therapy followed by immunosuppression withdrawal on disease recurrence in 10 children and 20 adults with MCD/MesGN (n=22) or FSGS who had suffered ≥2 recurrences over the previous year and were in steroid-induced remission for ≥1 month. Participants received one dose (n=28) or two doses of rituximab (375 mg/m(2) intravenously). At 1 year, all patients were in remission: 18 were treatment-free and 15 never relapsed. Compared with the year before rituximab treatment, total relapses decreased from 88 to 22 and the per-patient median number of relapses decreased from 2.5 (interquartile range [IQR], 2-4) to 0.5 (IQR, 0-1; P<0.001) during 1 year of follow-up. Reduction was significant across subgroups (children, adults, MCD/MesGN, and FSGS; P<0.01). After rituximab, the per-patient steroid maintenance median dose decreased from 0.27 mg/kg (IQR, 0.19-0.60) to 0 mg/kg (IQR, 0-0.23) (P<0.001), and the median cumulative dose to achieve relapse remission decreased from 19.5 mg/kg (IQR, 13.0-29.2) to 0.5 mg/kg (IQR, 0-9.4) (P<0.001). Furthermore, the mean estimated GFR increased from 111.3±25.7 to 121.8±29.2 ml/min per 1.73 m(2) (P=0.01), with the largest increases in children and in FSGS subgroups. The mean height z score slope stabilized in children (P<0.01). Treatment was well tolerated. Rituximab effectively and safely prevented recurrences and reduced the need for immunosuppression in steroid-dependent or frequently relapsing nephrotic syndrome, and halted disease-associated growth deficit in children.

Rituximab treatment for relapsing minimal change disease and focal segmental glomerulosclerosis: a systematic review

BACKGROUND

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remain a therapeutic challenge, since steroids and other immunosuppressive agents exhibit an unfavorable adverse event spectrum. The aim of this review was to systematically summarize and analyze data from preexisting studies reporting the outcome of rituximab (RTX) treatment in these patients.

METHODS

Study data on adult patients with either steroid-dependent or frequently relapsing MCD/FSGS were identified by a PubMed and Embase search. The number of relapses was calculated and the use of immunosuppressive co-medication prior to and after RTX treatment was quantified.

RESULTS

We identified 14 studies including 86 patients with frequently relapsing and steroid-dependent MCD or FSGS. Treatment with RTX reduced the number of relapses per year from 1.3 (0-9) relapses prior to treatment compared to 0 (0-2) after therapy (p < 0.001). Proteinuria decreased from 2.43 (0-15) g/day to 0 (0-4.89) g/day (p < 0.001), while serum albumin increased from 2.9 (1.2-4.6) at baseline to 4.0 (1.8-5.09) g/l after RTX (p = 0.001). The use of immunosuppression used at the time of RTX administration was also reduced after RTX therapy (p < 0.001). Baseline serum albumin was lower (p = 0.018), whereas the number of immunosuppressants prior to RTX was higher (p = 0.018) in patients with relapse after RTX.

CONCLUSIONS

The published data suggest that RTX is effective in reducing the number of relapses and sparing immunosuppression in frequently relapsing and steroid-dependent nephrotic syndrome due to MCD and FSGS. These promising findings have to be confirmed in controlled and prospective studies.

Novel use of rituximab for steroid-dependent nephrotic syndrome in children

BACKGROUND

Though rituximab (RTX) is effective for childhood steroid-dependent nephrotic syndrome (SDNS), an established regimen does not exist. The relapses tend to occur when the peripheral blood B-cell count re-arises at 3 months upon single RTX infusion. This study was conducted to clarify whether the long-term remission of SDNS can be obtained by repeated RTX administrations.

METHODS

RTX was administered 4 times at 3-month intervals at 375 mg/m(2)/time to 5 children with SDNS. The changes in the clinical indicators were analyzed.

RESULTS

The median (range) observation period was 6.3 (0.9-8.4) years before RTX and 3.2 (1.9-3.8) years following the commencement of RTX. The changes in the clinical indicators were as follows (median and range): (1) annual number of relapses: before administration 1.4 (1.1-3.5) times/year, after administration 0.0 (0.0-0.0) times/year, and (2) median steroid dosage: before administration 0.80 (0.23-0.96) mg/kg/day, after administration 0.00 (0.00-0.00) mg/kg/day. All changes were significant at p < 0.05. Relapse occurred 3 times following the start of RTX (the period to relapse was 2.2, 1.9, and 2.3 years, respectively). No serious side effects were seen.

CONCLUSIONS

Repeated RTX against SDNS in children may be a useful therapeutic option.

Does rituximab induce hypogammaglobulinemia in patients with pediatric idiopathic nephrotic syndrome?

BACKGROUND

Rituximab (RTX) is a promising strategy for treating steroid-dependent idiopathic nephrotic syndrome (SDNS). RTX induces profound B-cell depletion, suggesting hypogammaglobulinemia as a potential side effect after long-term treatment.

PATIENTS AND METHODS

We analyzed immunoglobulin G (IgG) levels in 12 pediatric patients on RTX with a B-cell depletion of a minimum of 3 months and compared the results to 16 patients on orally administered immunosuppressive drugs, such as mycophenolate mofetil (MMF) and/or cyclosporine A (CyA). All patients were in stable remission of SDNS at the time of IgG analysis.

RESULTS

IgG levels in the RTX group before RTX introduction were 6.2 ± 1.0 g/L and were not significantly different from the MMF/CyA group (8.2 ± 2.5 g/L). In the MMF/CyA group, five patients had at least one episode of hypogammaglobulinemia. In two of them, this episode was prolonged (>3 months), and only one required IgG supplementation. In the RTX group, eight patients had decreased IgG levels before RTX infusion. After RTX, hypogammaglobulinemia persisted in seven among those eight patients. No decreased IgG plasma levels were noted in patients with normal baseline IgG levels before RTX treatment.

CONCLUSION

RTX does not seem to directly induce decreased IgG levels in patients with SDNS, but it seems to prolong a preexisting low IgG levels.

The treatment of minimal change disease in adults

Minimal change disease (MCD) is the etiology of 10%-25% of cases of nephrotic syndrome in adults. The mainstay of treatment for adult MCD, oral glucocorticoids, is based on two randomized controlled trials and extensive observational data in adults, and this treatment leads to remission in over 80% of cases. Relapses are common, and some patients become steroid-resistant (SR), steroid-dependent (SD), or frequently relapsing (FR). The data guiding the treatment of these patients are limited. Here, we review MCD in adults with particular focus on the evidence for immunosuppressive therapy in these patients.

Rituximab is an efficient and safe treatment in adults with steroid-dependent minimal change disease

Development of steroid dependency in patients with nephrotic syndrome may require a long-term multi-drug therapy at risk of drug toxicity and renal failure. Rituximab treatment reduces the steroid dosage and the need for immunosuppressive therapy in pediatric patients. Here we retrospectively analyze the efficacy and safety of rituximab in adult patients with steroid-dependent minimal change disease. To do this, we analyzed the outcome of all adult patients treated with rituximab for steroid-dependent minimal change nephrotic syndrome over a mean follow-up of 29.5 months (range 5.1-82 months). Seventeen patients with steroid-dependent or frequently relapsing minimal change nephrotic syndrome, unresponsive to several immunosuppressive medications, were treated with rituximab. Eleven patients had no relapses after rituximab infusion (mean follow-up 26.7 months, range 5.1-82 months) and nine of them were able to come off all other immunosuppressive drugs and steroids during follow-up. Six patients relapsed at least once after a mean time of 11.9 months (mean follow-up 34.5 months, range 16.9-50.1 months), but their immunosuppressive drug treatment could be stopped or markedly reduced during this time. No adverse events were recorded. Thus, rituximab is efficient and safe in adult patients suffering from severe steroid-dependent minimal change disease. Prospective randomized trials are needed to confirm this study.

Effect of single-dose rituximab on steroid-dependent minimal-change nephrotic syndrome in adults

BACKGROUND

Steroid-dependent minimal-change nephrotic syndrome (MCNS) requires administration of prolonged courses of prednisolone (PSL); therefore, a paradigm shift from such toxic 'non-specific' therapies to selective immunomodulating regimens is necessary for these cases.

METHODS

To assess the therapeutic effects of rituximab (an anti-CD20 antibody) in adult patients with steroid-dependent MCNS, we performed a prospective trial of the effects of a single dose of rituximab administered twice at an interval of 6 months in 25 MCNS patients. We evaluated the biochemical parameters and compared the clinical findings between the 12-month period before and 12-month period after the first rituximab infusion.

RESULTS

A significant reduction in the number of relapses and the total dose and the maintenance dose of PSL administered was observed during the 12-month period after the first rituximab infusion when compared with the findings during the 12-month period before the first rituximab infusion [25 (100%) versus 4 (16%), P < 0.001; 8.2 versus 3.3 g, P < 0.001; 26.4 mg/day at baseline versus 1.1 mg/day at 12-month, P < 0.0001]. Complete remission was achieved/maintained in all patients undergoing B-cell depletion. Four of 17 patients with B-cell repletion developed relapse.

CONCLUSIONS

Our results revealed that rituximab therapy was associated with a reduction in the number of relapses and in the total dose of PSL needed. Therefore, rituximab appears to be a useful therapeutic agent for adult patients with steroid-dependent MCNS. These results suggest that this treatment is rational and should be considered as an important option in the management of adult patients with steroid-dependent MCNS.

Second-line options for refractory steroid-sensitive and -resistant nephrotic syndrome

Although initially, many children with idiopathic nephrotic syndrome respond to steroid therapy, a repeated course for patients with relapses often causes significant steroid toxicity. Patients with frequent relapses or steroid dependency thus require alternative treatment, and so far, cyclophosphamide or levamisole have been regarded as first-choice options, although the latter is no longer available in many countries. Data are accumulating that mycophenolic acid may be an alternative for these patients. Calcineurin inhibitors (cyclosporine A or tacrolimus) are usually effective and are often used after cytotoxic treatment, but long-term treatment is necessary, raising concerns regarding the accumulation of side effects. Still, some patients show a tendency to relapse even on this maintenance regimen and some even have a refractory course that creates a medical dilemma. For this situation, recent data have demonstrated an effect of monoclonal antibodies directed to B cells - rituximab, a drug that may also prove to be a therapeutic option in less complicated cases. Patients that do not respond to initial steroid treatment need genetic testing and a renal biopsy, since focal segmental glomerulosclerosis may be present. Treatment options include pulse methylprednisolone, often in addition to calcineurin inhibitors (mainly cyclosporine but also, recently, tacrolimus). Cyctotoxic treatment, especially intravenous cyclophosphamide, has been found to be effective in steroid-resistant nephrotic syndrome by some studies but is inferior to calcineurin inhibitors. In addition, mycophenolic acid and rituximab have been used in children with primary focal segmental glomerulosclerosis; however, response seems to be inferior in comparison with patients with steroid-sensitive nephrotic syndrome. Taken together, idiopathic nephrotic syndrome, including steroid-sensitive as well as steroid-resistant patients, is a potentially serious disorder. Although much progress has been made in recent years and a wide arsenal of immunological interventions is available, some patients have a treatment refractory course. Prospective studies or at least standardization of treatment for complicated cases is urgently needed.

[Pathogenesis and treatment of idiopathic nephrotic syndrome in adults]

Idiopathic nephrotic syndrome is the most frequent glomerular disease in children and in young adults. While genetic analyses have provided new insights into disease pathogenesis through the discovery of several podocyte genes mutated in distinct forms of inherited nephrotic syndrome, the molecular bases of minimal change nephrotic syndrome and focal and segmental glomerulosclerosis with relapses remain unclear. Although immune cell disorders, which may involve both innate and adaptive immunity, appear to play a role in the pathogenesis of steroid sensitive minimal change nephrotic syndrome, the mechanisms by which they induce podocyte dysfunction remain unresolved. It was postulated that podocyte injury results from a circulating factor secreted by abnormal T cells, but the possibility that bipolarity of the disease results from a functional disorder shared by both immune cells and the podocytes is not excluded. Minimal change nephrotic syndrome relapses are associated with an expansion of T and B cell compartments and production of growth factors as well as many cytokines. Dysfunction of T cells is supported by several findings including, inhibition of a type IV hypersensitivity reaction and unclassical T helper polarization, resulting from transcriptional interference between Th1 and Th2 transcriptional factors. A low serum level of some IgG fractions is frequently observed suggesting a defect in T-B cell cooperation, which remains to be explored. In this review, we discuss recent advances in the pathogenesis and the therapy of idiopathic nephrotic syndrome.

Rituximab treatment for adult patients with focal segmental glomerulosclerosis

We present two cases with steroid-resistant nephrotic syndrome (SRNS) and two cases with steroid-dependent nephrotic syndrome (SDNS) due to focal segmental glomerulonephritis (FSGS) who were treated with a single dose of rituximab (375 mg/m(2)). Although the two cases with SRNS showed no response, the two cases with SDNS achieved complete remission. The patients in whom the peripheral B-cell counts subsequently increased after the administration of rituximab demonstrated a relapse. Rituximab may be an effective treatment agent for SDNS with FSGS and the peripheral B-cell count may be a useful marker in such patients for preventing disease relapse.

Should we consider MMF therapy after rituximab for nephrotic syndrome?

The management of steroid-dependent nephrotic syndrome, especially in patients who have failed to respond to cytotoxic drugs, such as cyclophosphamide, remains challenging. Rituximab represents a new (off-label) therapeutic option. In a significant portion of patients, it has a short serum half-life following the recovery of CD20-positive cells. The addition of mycophenolate mofetil (MMF) as a maintenance therapy is also an attractive option, but one which requires testing in a prospective randomized clinical trial with therapeutic drug monitoring and mechanistic ancillary studies.

New therapies in steroid-sensitive and steroid-resistant idiopathic nephrotic syndrome

Although many children with idiopathic nephrotic syndrome (INS) respond initially to steroid therapy, repeated courses for patients with relapses often cause significant steroid toxicity. Patients with frequent relapses who develop steroid dependency thus require alternative treatment. The first such options have been considered to be cyclophosphamide or levamisole, although the latter is no longer available in many countries. There is also an increasing body of data indicating that mycophenolic acid (MPA) may be an alternative for these patients. Calcineurin inhibitors (cyclosporine A or tacrolimus) are usually effective and often used after cytotoxic treatment, but long-term treatment with these agents is necessary, raising concerns of a possible accumulation of side effects. Some patients show a tendency to relapse even on such maintenance regimens, and some even have a refractory course that creates a medical dilemma. For this situation, recent data indicate that monoclonal antibodies directed to B-cells (e.g. rituximab) may have some effect and that such drugs may also prove to be a therapeutic option in less complicated cases. Patients that do not respond to steroid treatment need genetic testing and a renal biopsy since focal segmental glomerulosclerosis (FSGS) may be present. Treatment options include pulse methylprednisolone, often in addition to calcineurin inhibitors, mainly in the form of cyclosporine, but tacrolimus has also come into recent favor. Some studies have found cytotoxic treatment, especially intravenous cyclophosphamide, to be effective in steroid resistant nephrotic syndrome, but it seems to be inferior to calcineurin inhibitors. MPA and rituximab have also been used in children with primary FSGS, but the response seems to be inferior to that in patients with steroid sensitive nephrotic syndrome. Taken together, INS in both steroid-sensitive and steroid-resistant patients is a potentially complicated disorder, and despite a wide arsenal of immunological interventions, some patients have a treatment refractory course. Prospective studies or at least standardized treatment for complicated cases is urgently needed.

Rituximab and minimal change nephrotic syndrome: a therapeutic option

Minimal change nephrotic syndrome (MCNS) usually responds to steroids but frequently relapses, requiring additional treatment with immunosuppressive agents. Rituximab is a chimeric murine/human monoclonal immunoglobulin G1 antibody that targets CD20, a B-cell differentiation marker. B-cell recovery begins at approximately 6 months following the completion of treatment. Rituximab has a beneficial effect, with the sustained remission or reduction of proteinuria in patients with steroid-dependent MCNS. Relapses are thought to be associated with an increase in CD19 cells. The mean serum half-life of rituximab was reported to be 10-15 days in patients with steroid-dependent nephrotic syndrome. Only infusion reactions, such as rash and chills, occurred after single-dose rituximab infusion and can be managed by pre-medication or infusion rate adjustments. Even though severe adverse effects of rituximab are not expected, physicians must be aware of potentially life-threatening adverse effects. Controlled randomized trials that include adult patients with steroid-dependent or steroid-resistant MCNS are required to prove the efficacy and safety of rituximab and to evaluate the cost-effectiveness of rituximab treatment.

Effect of single-dose rituximab on primary glomerular diseases

BACKGROUND

A paradigm shift from such toxic 'nonspecific' therapies to selective immunomodulating regimens is necessary for glomerular diseases. Rituximab, which acts by inhibiting CD20-mediated B cell proliferation and differentiation, could be effective in the treatment of nephrotic syndrome as shown in recent reports.

DESIGN

To assess the effects of rituximab in patients with primary glomerular diseases, including minimal-change disease, immunoglobulin A (IgA) nephropathy, focal segmental glomerulonephritis, membranous nephropathy and membranoproliferative glomerulonephritis, we performed a prospective trial of the effects of single-dose rituximab therapy in 24 patients. We prospectively evaluated the serum and urinary biochemical parameters before and after 6 months of therapy.

RESULTS

In all of the patients studied, depletion of CD19 and CD20 cells was noted, with significant reduction in the degree of proteinuria from 3.7 ± 3.4 g/day at baseline to 1.3 ± 2.0 g/day at 6 months after the drug administration (p = 0.002). However, no significant changes of the serum creatinine, urinary RBC sediment, serum CD4/8 or serum IL-4 levels were observed at 6 months after the drug administration. In subjects with IgA nephropathy, while depletion of CD19 and CD20 cells was noted, no significant change in the severity of proteinuria was observed at 6 months after the drug administration as compared with the level at the baseline.

CONCLUSION

For the treatment of primary glomerular diseases, the use of a single dose of rituximab is demonstrated with no serious adverse events. Further study of the mechanism of action of rituximab in successfully treated patients could encourage new perspectives in the treatment of primary glomerular diseases.