Recurrent focal segmental glomerulosclerosis after kidney transplantation

Efficacy and Safety of Bleselumab in Preventing the Recurrence of Primary Focal Segmental Glomerulosclerosis in Kidney Transplant Recipients: A Phase 2a, Randomized, Multicenter Study

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage kidney disease and frequently recurs after kidney transplantation. Recurrent FSGS (rFSGS) is associated with poor allograft and patient outcomes. Bleselumab, a fully human immunoglobulin G4 anti-CD40 antagonistic monoclonal antibody, disrupts CD40-related processes in FSGS, potentially preventing rFSGS.

METHODS

A phase 2a, randomized, multicenter, open-label study of adult recipients (aged ≥18 y) of a living or deceased donor kidney transplant with a history of biopsy-proven primary FSGS. The study assessed the efficacy of bleselumab combined with tacrolimus and corticosteroids as maintenance immunosuppression in the prevention of rFSGS >12 mo posttransplantation, versus standard of care (SOC) comprising tacrolimus, mycophenolate mofetil, and corticosteroids. All patients received basiliximab induction. The primary endpoint was rFSGS, defined as proteinuria (protein-creatinine ratio ≥3.0 g/g) with death, graft loss, or loss to follow-up imputed as rFSGS, through 3 mo posttransplant.

RESULTS

Sixty-three patients were followed for 12 mo posttransplantation. Relative decrease in rFSGS occurrence through 3 mo with bleselumab versus SOC was 40.7% (95% confidence interval, -89.8 to 26.8; P = 0.37; absolute decrease 12.7% [95% confidence interval, -34.5 to 9.0]). Central-blinded biopsy review found relative (absolute) decreases in rFSGS of 10.9% (3.9%), 17.0% (6.2%), and 20.5% (7.5%) at 3, 6, and 12 mo posttransplant, respectively; these differences were not statistically significant. Adverse events were similar for both treatments. No deaths occurred during the study.

CONCLUSIONS

In at-risk kidney transplant recipients, bleselumab numerically reduced proteinuria occurrence versus SOC, but no notable difference in occurrence of biopsy-proven rFSGS was observed.

Focal Segmental Glomerulosclerosis

Focal segmental glomerular sclerosis (FSGS) is a histological lesion characterized by sclerosis in sections (segmental) of some glomeruli (focal) in association with podocyte injury. Historically, FSGS has often been characterized as a disease, but it is a heterogeneous entity based on etiology, clinical course, and therapeutic approach. A unifying feature is podocyte injury and loss, which can be primary or the result of secondary maladaptive responses to glomerular stressors. FSGS has been demonstrated over time to carry a large health burden and remains a leading glomerular cause of ESRD globally. Recent clinical practice guidelines highlight the unmet scientific need for better understanding of disease pathogenesis, particularly for immunologic etiologies, as well as more targeted therapeutic drug development. In this review, we will discuss the current FSGS classification scheme, pathophysiologic mechanisms of injury, and treatment guidelines, along with emerging and investigational therapeutics.

Sparsentan for Focal Segmental Glomerulosclerosis in the DUET Open-Label Extension: Long-term Efficacy and Safety

Rationale & Objective

Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist (DEARA) examined in the ongoing phase 2 DUET trial for focal segmental glomerulosclerosis (FSGS). In the DUET 8-week double-blind period, sparsentan resulted in greater proteinuria reduction versus irbesartan. We report the long-term efficacy and safety of sparsentan during the open-label extension over more than 4 years.

Study Design

Patients were examined from their first sparsentan dose (double-blind period or open-label extension) through 4.6 years.

Setting & Participants

Patients with FSGS, excluding secondary FSGS.

Intervention

Sparsentan (200, 400, and 800 mg/d).

Outcomes

Urinary protein-creatinine ratio, FSGS partial remission endpoint (urinary protein-creatinine ratio ≤1.5 g/g and >40% reduction from baseline), estimated glomerular filtration rate, and blood pressure approximately every 12 weeks. Treatment-emergent adverse events by year and cases/100 patient-years.

Results

109 patients were enrolled; 108 received ≥1 sparsentan dose; 103 entered the open-label extension (68 sparsentan, 35 irbesartan during the double-blind period). Sparsentan was ongoing in 45/108 patients (41.7%); median time to treatment discontinuation was 3.9 years (95% CI, 2.6-5.2). Mean percent proteinuria reduction from baseline was sustained through follow-up. Achieving partial remission within 9 months of first sparsentan dose (52.8% of patients) versus not achieving (47.2%) was associated with significantly slower rate of estimated glomerular filtration rate decline over the entire treatment period (-2.70 vs -6.56; P = 0.03) and in the first 2 years (-1.69 vs -6.46; P = 0.03). The most common treatment-emergent adverse events (>9 cases/100 patient-years) were headache, peripheral edema, upper respiratory infection, hyperkalemia, and hypotension. Peripheral edema and hypotension declined from year 1 (13.9% and 15.7% of patients, respectively) to ≤4% in years ≥2. There were no cases of heart failure and no patient deaths.

Limitations

The open-label extension does not include a comparison group.

Conclusions

Long-term sparsentan treatment showed sustained proteinuria reduction and a consistent safety profile.

Kidney Failure Attributed to Focal Segmental Glomerulosclerosis: A USRDS Retrospective Cohort Study of Epidemiology, Treatment Modalities, and Economic Burden

Rationale & Objective

This study describes the epidemiology, characteristics, and clinical outcomes of patients with focal segmental glomerulosclerosis (FSGS)-attributed kidney failure in the US Renal Data System (USRDS) during 2008-2018, and health care resource utilization and costs among those with Medicare-linked data.

Study Design

This was a retrospective cohort study.

Setting & Population

Patients with FSGS-attributed kidney failure in the USRDS were enrolled in the study.

Outcomes

The outcomes were as follows: Prevalence and incidence, clinical and demographic characteristics, time to kidney transplant or death, health care resource utilization, and direct health care costs.

Analytical Approach

Patients with FSGS as the primary cause of kidney failure were followed from USRDS registration (index date) until death or data end. Prevalence and incidence were calculated per 1,000,000 US persons. Patient characteristics at index and treatment modalities during follow-up were described. Time to kidney transplant or death was assessed with Kaplan-Meier and competing risk analyses. Health care resource utilization and costs were reported among patients with 1 year Medicare Part A+B coverage postindex, including (Medicare Coverage subgroup) or excluding (1-year Medicare Coverage subgroup) those who died.

Results

The FSGS cohort and Medicare Coverage and 1-year Medicare Coverage subgroups included 25,699, 6,340, and 5,575 patients, respectively. Mean annual period prevalence and incidence rates of FSGS-attributed kidney failure were 87.6 and 7.5 per 1,000,000 US persons, respectively. Initial treatment for most patients was in-center hemodialysis (72.1%), whereas 7.3% received kidney transplant. Accounting for competing risk of death, year 1 and 5 kidney transplant rates were 15% and 34%, respectively. In the Medicare Coverage and 1-year Medicare Coverage subgroups, 76.6% and 74.2% required inpatient admission, 69.9% and 67.3% visited the emergency room, and mean monthly health care costs were $6,752 and $5,575 in the year postindex, respectively.

Limitations

Drug costs may be underestimated because Medicare Part D coverage was not required; kidney acquisition costs were not available.

Conclusions

FSGS-attributed kidney failure is associated with substantial clinical and economic burden, prompting the need for novel therapies for FSGS to delay kidney failure.

Incidence, risk factors, and outcomes of recurrent focal segmental glomerulosclerosis in pediatric kidney transplant recipients: A systematic review and meta-analysis

BACKGROUND

Focal segmental glomerulosclerosis is the most prevalent acquired kidney disease leading to end-stage renal disease in children and has a propensity for recurring in the transplanted kidney. The recurrence of FSGS after kidney transplantation in children varies greatly. In addition, the risk factors and outcomes of recurrence of FSGS remain controversial. This study evaluated the recurrence rate, risk factors, and prognosis of FSGS after kidney transplantation in order to provide advice and assistance in clinical decision-making for pediatric kidney transplantation.

METHODS

PubMed, Embase, Web of Science, CNKI, and other databases were searched from the establishment of the repository to March 2022. We extracted data on incidence, risk factors, and outcomes.

RESULTS

The results showed that the recurrence rate of primary FSGS in children after renal transplantation was 48% (95% CI 36%-59%) and the recurrence rate of FSGS (all forms) was 35% (95% CI 17%-52%). The graft loss rate of primary FSGS in children after kidney transplantation was 29% (95% CI 17%-42%) and the graft loss rate of FSGS (all forms) was 29% (95% CI 4%-62%). 57% (95% CI 42%-73%) of pediatric patients with recurrent primary FSGS showed complete remission. Risk factor analyses showed that age of onset (SMD .69, 95% CI .20-1.19, p = .006) was related to the recurrence of primary FSGS, whereas the living related donor was not a risk factor for recurrent primary FSGS in pediatrics after kidney transplantation (OR 1.22, 95% CI .48-3.10, p = .674).

CONCLUSIONS

The recurrence rate and graft loss rate of FSGS in children after kidney transplantation were relatively high. Age at onset was associated with a risk for recurrent primary FSGS, whereas the living related donor was not a risk factor for recurrent FSGS in pediatric kidney recipients.

Implications of Complete Proteinuria Remission at any Time in Focal Segmental Glomerulosclerosis: Sparsentan DUET Trial

Introduction

Focal segmental glomerulosclerosis (FSGS) is a rare glomerular disease with high unmet clinical need. Interest in proteinuria as a surrogate end point for regulatory approval of novel treatments has increased. We assessed the relationship between achieving complete remission (CR) of proteinuria at least once during follow-up and long-term kidney outcomes.

Methods

This post hoc analysis included all patients enrolled in the DUET trial of sparsentan in FSGS and the open-label extension (OLE). Evaluations occurred every 12 weeks, including blood pressure (BP), edema, proteinuria, and kidney function. CR was defined as a urine protein/creatinine ratio ≤0.3g/g in a first morning urine sample.

Results

A total of 108 patients who received ≥1 sparsentan dose were included in this study. During a median follow-up of 47.0 months, 46 patients (43%) experienced ≥1 CR, 61% occurring within 12 months of starting sparsentan. There was an increased likelihood of CR with a higher sparsentan dose or baseline subnephrotic-range proteinuria. Achieving ≥1 CR was associated with significantly slower rate of estimated glomerular filtration rate (eGFR) decline versus non-CR patients (P < 0.05). Use of immunosuppressive agents was more frequent in patients who achieved a CR. However, the antiproteinuric effect of sparsentan was additive to that achieved with concomitant immunosuppressive treatment. No unanticipated adverse events occurred.

Conclusion

We conclude that sparsentan can be safely administered for extended periods and exerts a sustained antiproteinuric effect. Achievement of CR at any time during follow-up, even if it is not sustained, may be an indicator of a favorable response to treatment and a predictor of improved kidney function outcomes.

Response to steroid and immunosuppressive therapies may predict post-transplant recurrence of steroid-resistant nephrotic syndrome

BACKGROUND

Recurrence of SRNS is a major challenge in KT. Several clinical factors, including initial steroid sensitivity, have been associated with increased post-transplant SRNS recurrence risk. However, conflicting data have been reported, possibly due to the heterogeneous pathophysiology of SRNS and the lack of genetic testing of SRNS patients. Furthermore, the response to immunosuppressive therapies has not been evaluated.

METHODS

Seventy patients aged 1-15 years at SRNS onset who underwent KT between 2002 and 2018 were enrolled. Patients with secondary, familial, syndromic, and genetic forms of SRNS and those who were not treated with steroid were excluded. This study aimed to assess the risk factors for post-transplant recurrence, including treatment responses to initial steroid therapy and additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A.

RESULTS

Data from 36 kidney transplant recipients were analyzed. Twenty-two (61%) patients experienced post-transplant SRNS recurrence, while 14 patients did not. The proportion of patients who achieved complete or partial remission with initial steroid therapy and/or additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A was significantly higher in the SRNS recurrence group (19/22, 86%) than in the group without SRNS recurrence (6/14, 43%; p = .01).

CONCLUSION

This study suggests that the response to steroid treatment, other immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A may predict post-transplant SRNS recurrence.

Primary Focal Segmental Glomerulosclerosis Recurrence After Pediatric Renal Transplantation

OBJECTIVES

Focal segmental glomerulosclerosis recurrence after renal transplant occurs frequently in pediatric patients and is associated with poor graft survival when patients reach adulthood. We investigated recurrence rates, recurrence risk factors, management strategies, and long-term graft function among pediatric renal transplant recipients with focal segmental glomerulosclerosis as primary disease.

MATERIALS AND METHODS

We retrospectively evaluated medical records of 34 pediatric patients with primary focal segmental glomerulosclerosis who had undergone renal transplant between 2004 and 2019 at our center. Focal segmental glomerulosclerosis recurrence was diagnosed by the presence of nephrotic range proteinuria after transplant and confirmed by graft biopsy. Preoperative prophylactic plasma exchange was administered to pediatric renal transplant recipients with primary focal segmental glomerulosclerosis. Plasma exchange was also used to treat focal segmental glomerulosclerosis recurrence, with rituximab added if the patient did not respond to plasma exchange.

RESULTS

All patients (male-to-female ratio of 19:15) in our group underwent renal transplant. Mean patient age at the time of transplant was 12.72 ± 5.46 years. Twenty-nine patients received living- related donor allografts (85.3%) and 5 received organs from deceased donors (14.7%). We identified focal segmental glomerulosclerosis recurrence in 5 recipients (14.7%). Time from focal segmental glomerulosclerosis diagnosis to end-stage renal disease and duration of dialysis were shorter in the recurrence group than in the nonrecurrence group (48.4 months [range, 2-90 mo] vs 65.1 months [range, 8-123 mo] and 1.41 ± 0.82 vs 3.18 ± 1.88 years, respectively; P < .05). Donor type and transplant age were similar in both groups. Of those with recurrence who had received plasma exchange and rituximab, 3 patients (75%) had complete remission and 1 patient (25%) had partial remission.

CONCLUSIONS

Prophylactic plasma exchange and the combined plasma exchange-rituximab regimen for treatment of focal segmental glomerulosclerosis recurrence resulted in low recurrence and good remission rates in our pediatric cohort.

Application of adrenocorticotropic hormone in recurrent focal segmental glomerulosclerosis post-transplantation: A case report and literature review

BACKGROUND

The recurrence rate of focal segmental glomerulosclerosis (FSGS) post-renal transplantation is as high as 30%-50%. However, the pathogenesis is unclear. At present, there is no unified standard for the treatment of recurrent FSGS post-transplantation. Its treatment is full of risks and challenges.

METHODS

We report a child with recurrent FSGS with massive proteinuria 6~9 g/m² /day and resistance to plasma exchange (PE) and rituximab (RTX). On the basis of receiving anti-rejection therapy of prednisone, tacrolimus, and mycophenolate mofetil (MMF), we treated the child with adrenocorticotropic hormone (ACTH), and reviewed the literature on the application of ACTH in the recurrence of FSGS post-transplantation.

RESULTS

After 1 year of treatment with ACTH, the patient's urinary protein decreased and fluctuated between 0.6 and 1.1 g/m² /day. The albumin (ALB) and cholesterol (CHOL) returned to the normal range. The patient achieved complete remission after 19 months of ACTH treatment and maintained until now. There was no obvious adverse reaction. Literature review showed that up to February 2021, a total of 8 studies showed the use of ACTH in kidney transplant patients, and all the patients in the study achieved remission.

CONCLUSIONS

ACTH is a potential option for treating recurrent FSGS post-transplantation with fewer side effects and relatively safe for patients. However, further evaluation is needed to better adapt to different populations.

Kidney Transplantation for Focal Segmental Glomerulosclerosis: Can We Prevent Its Recurrence? Personal Experience and Literature Review

Background: Primary focal segmental glomerulosclerosis (FSGS) is associated with a high risk of recurrence after kidney transplantation with a major risk of graft loss despite preventive or curative treatments. Aim: to assess graft survival in FSGS kidney-transplant recipients and to compare those that had a relapse with those that had no relapse. Patients/Methods: we included 17 FSGS kidney-transplant recipients between January 2000 and January 2020, separated retrospectively into two groups (recurrences: n = 8 patients; no recurrences: n = 9 patients). FSGS recurrence was defined as having proteinuria of ≥3 g/g or urinary creatinine of ≥3 g/day. All patients received an induction therapy; maintenance immunosuppressive therapy at post-transplantation relied on tacrolimus/mycophenolate mofetil/steroids. In order to prevent or treat FSGS recurrence, patients received apheresis sessions plus rituximab. Results: FSGS recurrence rate was 47%. All patients that relapsed with a first graft also relapsed with subsequent grafts. Median time to recurrence was 3 (min: 1; max: 4745) days, despite rituximab/apheresis prophylaxis. Mean age was significantly lower in the relapsers (group 1) than in the non-relapsers (group 2); i.e., 47 ± 11 vs. 58 ± 9 years (p = 0.04). Time to progression to stage 5 chronic kidney disease (CKD) and young age at FSGS diagnosis were lower in group 1 compared to group 2; i.e., 5 (min: 1; max: 26) vs. 2 (min: 1; max: 26) years, and 16 (min: 4; max: 55) vs. 34 (min: 6; max 48) years, respectively. There was no difference between the two groups in terms of progression to CKD stage 5 on the native kidneys, averaging 7 years in both groups (p = 0.99). In group 1, seven patients received rituximab/apheresis prophylaxis, although this did not prevent the recurrence of FSGS. Conclusion: pretransplant prophylaxis with plasmapheresis/rituximab did not appear to reduce the risk of recurrence of primary FSGS on the graft, but could allow remission in the event of recurrence.

Re-transplantation in pediatric patients with failure of primary transplant due to recurrent focal segmental glomerulosclerosis: A pediatric nephrology research consortium study

INTRODUCTION

Recurrent focal and segmental glomerulosclerosis (FSGS) in kidney transplant recipients is associated with lower graft survival and increased morbidity. There are limited data to guide the decision to re-transplant patients with transplant failure due to FSGS recurrence. We aimed to evaluate outcomes in patients re-transplanted after having initial graft failure due to recurrent FSGS and to study physician attitudes and practice patterns.

METHODS

Retrospective data from 10 centers were collected on 20 patients transplanted between January 1997 and September 2018. A survey was sent to nephrologist members of the Pediatric Nephrology Research Consortium.

RESULTS

Mean patient age (years) was 9.8 ± 4.8 at first transplant and 15.9 ± 4.9 at re-transplantation. Pre-transplant plasmapheresis was used in 1 (5.3%) primary transplant vs. 7 (38.9%) re-transplants (p = .03). Nephrotic syndrome recurred in 14 patients (70%) after re-transplantation and was severe in 21.1% vs. 64.7% after first transplant (p = .04). Graft survival was significantly higher in the second transplant (p .009) with 70% having functioning grafts at a median of 25.2 months. Thirty-one physicians from 21 centers completed the survey, 94% indicated they would re-transplant such patients, 44.4% preferred a minimum waiting period before re-transplantation, 36.4% preferred living donors, and 22.2% indicated having protocols for re-transplantation at their centers.

CONCLUSIONS

Consideration for re-transplantation is high among pediatric nephrologists. Pre-transplant plasmapheresis was more frequent in re-transplanted patients. Nephrotic syndrome recurrence was less severe, with better graft survival. More data and a larger population are necessary to further evaluate outcome determinants and best practices in this special population.

Ofatumumab treatment for nephrotic syndrome recurrence after pediatric renal transplantation

BACKGROUND

Relapsing nephrotic syndrome (NS) after transplantation can be a challenge to treat. The result of the consequent long-lasting proteinuria is the loss of the graft. Disease recurrence after renal transplantation occurs in around half of cases, and the efficacy of therapeutic strategies is often limited. Recently, ofatumumab, a second-generation and fully human anti-CD20 monoclonal antibody, has been shown to be effective in severe situations.

METHODS

We retrospectively collected data from the medical records of children with recurrence of NS after renal transplantation treated with ofatumumab in France, after failure of previous treatments.

RESULTS

Six patients were included in this study in five centers with a median duration of follow-up of 10.5 months. Two different ofatumumab regimens were administered. The primary outcome was proteinuria at 6 months after the last dose of ofatumumab. No patient achieved a complete remission, 3/6 had a partial remission, and 3/6 had no response to ofatumumab. Four patients exhibited a minor allergic reaction with the first infusion. One patient died of infection, as a consequence of multiple factors. No malignancies were observed; however, the time of follow-up was not sufficient to see such disease.

CONCLUSIONS

Altogether, these results suggest ofatumumab has a poor efficacy in treating recurrence of NS after renal transplantation. However, it could be discussed in multidrug-resistant refractory NS, but infectious complications and overimmunosuppression have to be balanced. There is a need for further studies to confirm these findings and safety and to determine a standardized protocol in this indication.

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

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

Focal Segmental Glomerulosclerosis and Scheduled Pretransplant Plasmapheresis: A Timely Diagnosis of Nail-Patella Syndrome Avoided More Futile Immunosuppression

Focal and segmental glomerulosclerosis (FSGS) is a histopathological pattern of injury. As such, it encompasses a wide variety of dissimilar entities with different pathophysiologic mechanisms. Although ultrastructural morphological characteristics can specifically diagnose certain diseases and genetic mutations can also be unravelled, this ideal situation is generally not available worldwide. In this respect, when proteinuria with or without nephrotic syndrome is encountered and FSGS is the histological lesion, patients start to be prescribed different regimes of immunosuppression, which should only be indicated in cases of primary FSGS, a rare entity that is elusive to response and can hardly be precisely diagnosed. We present a 35-year-old female patient with a life-long diagnosis of FSGS and a heavy burden of immunosuppressants, which had been unable to manage the persistent proteinuria that eventually led to end-stage kidney disease. She was referred to us to organize the kidney transplant. Plasmapheresis had been previously suggested to her to prevent the relapse of primary FSGS. A genetic test disclosed that the patient was heterozygous for LMX1B, and the diagnosis of nail-patella syndrome was made. In this entity, immunosuppression is not indicated, and there is no recurrence of the disease in the transplanted allograft.

LDL-apheresis-induced remission of focal segmental glomerulosclerosis recurrence in pediatric renal transplant recipients

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) in pediatric patients is typically difficult to treat and will progress to end-stage renal disease (ESRD) in about 10% of cases. Following kidney transplantation, FSGS can recur in up to 56% of renal allografts-with a near 100% recurrence in subsequent transplants.

METHODS

Four different pediatric centers across the USA and the UK employed a protocol using LDL-apheresis (LDL-A) and pulse solumedrol to treat recurrent FSGS after transplantation in seven patients. All the patients included in this series demonstrated immediate, or early, recurrence of FSGS, which clinically presented as nephrotic-range proteinuria within hours to days after implantation of the kidney.

RESULTS

All patients experienced reductions in urinary protein to creatinine ratios resulting in partial or complete remission. All patients demonstrated improvements in their estimated GFRs at their most recent follow-up since LDL-A discontinuation.

CONCLUSIONS

This case series describes the successful treatment, across four different pediatric centers, of seven pediatric patients with recurrent post-transplant FSGS using the Liposorber® LA-15 in combination with pulse solumedrol.

Intrinsic tumor necrosis factor-α pathway is activated in a subset of patients with focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is frequently found in biopsies of patients with steroid resistant nephrotic syndrome (SRNS). The pathogenesis of SRNS/FSGS is often unknown and the disease will recur in up to 50% of patients post-transplant, indicating the presence of circulating podocyte-toxic factor(s). Several studies have reported clinical improvement after anti-TNFα therapy. However, prediction of the clinical outcome in SRNS/FSGS is difficult, and novel predictive biomarkers are needed. An image-based assay, which measures disassembly of focal adhesion complexes in cultured podocytes, was used to ascertain the presence of podocyte toxic activity in SRNS/FSGS sera. Expression of TNFα pathway genes was analysed in the Nephroseq FSGS cohort and in cultured podocytes treated with SRNS/FSGS sera. Podocyte toxic activity was detected in 48/96 SRNS/FSGS patients. It did not correlate with serum TNFα levels, age, sex, ethnicity or glomerular filtration rate. In ~25% of the toxic samples, the toxicity was strongly inhibited by blockade of TNFα signaling. Transcriptional profiling of human FSGS biopsies and podocytes treated with FSGS sera revealed significant increases in expression of TNFα pathway genes. We identified patients with serum podocyte toxic activity who may be at risk for FSGS recurrence, and those patients in whom serum podocyte toxicity may be reversed by TNFα blockade. Activation of TNFα pathway genes occurs in podocytes of FSGS patients suggesting a causative effect of this pathway in response to circulating factor(s). In vitro analyses of patient sera may stratify patients according to prognostic outcomes and potential responses to specific clinical interventions.

European Society of Pediatric Nephrology survey on current practice regarding recurrent focal segmental glomerulosclerosis after pediatric kidney transplantation

INTRODUCTION

Primary FSGS is an important cause of ESRD in children. FSGS recurrence after kidney transplantation is associated with early graft loss. No guidelines for treatment of FSGS recurrence exist. We conducted a survey to gain insight into variation of treatment between centers.

METHODS

A survey was sent to all members of the ESPN on behalf of the "Renal Transplantation" and "Idiopathic Nephrotic Syndrome" working groups.

RESULTS

Fifty-nine nephrologists from 31 countries responded, reporting 807 FSGS patients, with 241 (30%) FSGS recurrences after transplantation. Recurrence varied from 0% to 100% between respondents. Native nephrectomy before or during transplantation was performed, respectively, always (37%), never (39%), or on clinical indication (17%). Half of the respondents started preventive treatment before transplantation, using PF (n = 10); R (n = 4); PF or IA, plus R (n = 9); cyclosporine (n = 2); or unknown (n = 4). Immunosuppressive therapy for patients without known mutations consisted of a combination of steroids, tacrolimus/cyclosporine, and MMF, with or without IL-2R-blockade in, respectively, 61% and 86% of the respondents. Sixty-three percent applied a similar regimen to patients with known mutations. FSGS recurrence was treated with PF or IA, plus R by 66% of respondents; 54% observed no response. Complete remission in >50% of patients was reported by 41% of the respondents.

DISCUSSION

FSGS recurrence after transplantation is common, but varies greatly between centers. We found great variability in preventive and therapeutic treatment regimens. Future research should focus on predisposing factors, including biopsy findings and genetic mutations, and standardized treatment.

FAM40A alters the cytoskeleton of podocytes in familial focal and segmental glomerulosclerosis by regulating F-actin and nephrin

INTRODUCTION

Familial focal and segmental glomerulosclerosis (FFSGS) was found in a large cohort of patients in our previous study. Under the sponsorship of the National Natural Science Foundation of China, we conducted linkage analysis and full exon sequencing on the genomes of 54 patients diagnosed with FFSGS. The results revealed a FAM40A gene signature in those patients. To determine whether FAM40A was associated with podocyte lesions and whether changes in the podocyte cytoskeleton could affect podocyte function, mouse podocytes (MPs) were used in this study.

MATERIAL AND METHODS

FAM40A silencing, over-expression and mutant-type over-expression models of renal MPs were established, whereby roles of wild-type FAM40A and mutant FAM40A (c.1562T>C, p521M>T) in regulating the function of the MP cytoskeleton were explored by using cellular immunofluorescence, RT-qPCR and Western blot.

RESULTS

FAM40A was expressed and localized in MPs and significantly enriched in the nucleus and perinuclear zone. Changes of FAM40A expression altered the morphology of the MPs and their cytoskeletal organization, which was characterized by disordered distribution of F-actin, loss of the foot process architecture and the functional protein of the slit diaphragm nephrin (p < 0.05 or p < 0.01). FAM40A mutation (p521M>T) led to the formation of round and blunt morphology of the MPs and loss of the foot-process structure. In addition, expression of the cytoskeletal protein F-actin was increased and concentrated in FAM40A mutated cells, whereas the expression of nephrin decreased in those cells (p < 0.01).

CONCLUSIONS

FAM40A played an important role in maintaining the normal morphology and function of MPs by stabilizing the cytoskeleton of MPs. Moreover, mutant FAM40A (p521M>T) was able to alter the morphology and cytoskeleton of the MPs, and to decrease the expression of nephrin, which may be the main factor contributing to FSGS.

Successful management of recurrent focal segmental glomerulosclerosis

Primary focal segmental glomerulosclerosis (FSGS) recurs in up to 55% of patients after kidney transplantation. Herein we report the successful management of recurrent FSGS. A 5-year-old boy with primary FSGS received a deceased donor renal transplant. Immediate and fulminant recurrence of FSGS caused anuric graft failure that was resistant to plasmapheresis and rituximab. After exclusion of structural or immunologic damage to the kidney by repeated biopsies, the allograft was retrieved from the first recipient on day 27 and transplanted into a 52-year-old second recipient who had vascular nephropathy. Immediately after retransplantation, the allograft regained function with excellent graft function persistent now at 3 years after transplant. After 2 years on hemodialysis, the boy was listed for kidney retransplantation. To prevent FSGS recurrence, pretreatment with ofatumumab was performed. Nephrotic range proteinuria still occurred after the second transplantation, which responded, however, to daily plasma exchange in combination with ofatumumab. At 8 months after kidney retransplantation graft function is good. The clinical course supports the hypothesis of a circulating permeability factor in the pathogenesis of FSGS. Successful ofatumumab pretreatment implicates a key role of B cells. Herein we provide a description of successful management of kidney failure by FSGS, carefully avoiding waste of organs.

Recurrence of nephrotic syndrome following kidney transplantation is associated with initial native kidney biopsy findings

BACKGROUND AND OBJECTIVES

Steroid-resistant nephrotic syndrome (SRNS) due to focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) is a leading cause of end-stage kidney disease in children. Recurrence of primary disease following transplantation is a major cause of allograft loss. The clinical determinants of disease recurrence are not completely known. Our objectives were to determine risk factors for recurrence of FSGS/MCD following kidney transplantation and factors that predict response to immunosuppression following recurrence.

METHODS

Multicenter study of pediatric patients with kidney transplants performed for ESKD due to SRNS between 1/2006 and 12/2015. Demographics, clinical course, and biopsy data were collected. Patients with primary-SRNS (PSRNS) were defined as those initially resistant to corticosteroid therapy at diagnosis, and patients with late-SRNS (LSRNS) as those initially responsive to steroids who subsequently developed steroid resistance. We performed logistic regression to determine risk factors associated with nephrotic syndrome (NS) recurrence.

RESULTS

We analyzed 158 patients; 64 (41%) had recurrence of NS in their renal allograft. Disease recurrence occurred in 78% of patients with LSRNS compared to 39% of those with PSRNS. Patients with MCD on initial native kidney biopsy had a 76% recurrence rate compared with a 40% recurrence rate in those with FSGS. Multivariable analysis showed that MCD histology (OR; 95% CI 5.6; 1.3-23.7) compared to FSGS predicted disease recurrence.

CONCLUSIONS

Pediatric patients with MCD and LSRNS are at higher risk of disease recurrence following kidney transplantation. These findings may be useful for designing studies to test strategies for preventing recurrence.

Treatment of recurrent focal segmental glomerulosclerosis post-kidney transplantation in Australian and New Zealand children: A retrospective cohort study

Disease recurrence affects around a third of renal transplants for children with FSGS and is associated with poor graft outcomes. Unfortunately, there are no large trials guiding treatment for recurrent FSGS. We aimed to describe current therapies and treatment response for recurrent FSGS in 4 centres in Australia and New Zealand. Data were collected on children (age <18 years) with recurrent FSGS (1990-2015). We reviewed patient charts to obtain clinical information. Ethics approval was obtained from the relevant boards. Complete records were available on 24 patients (62% female, 54% Caucasian). Median time to first recurrence was 4 days (IQR 2-5 days). There were 14 separate treatment regimens, involving an average of 2 agents. The most common therapies were plasma exchange (20/24 patients, 83%), cyclosporin (15/24, 63%), and methylprednisolone (9/24, 38%). Full remission was achieved in 15 (63%), partial remission in 2 (8%), and no remission in 7 (29%) patients. Of the patients with no remission, 5 lost their graft to recurrent disease and 1 to concurrent acute vascular rejection. The plethora of different treatment regimens reflects the poor evidence guiding management for recurrent FSGS. More research is needed to improve outcomes.

Randomized Clinical Trial Design to Assess Abatacept in Resistant Nephrotic Syndrome

Introduction

Treatment-resistant nephrotic syndrome is a rare form of glomerular disease that occurs in children and adults. No Food and Drug Administration-approved treatments consistently achieve remission of proteinuria and preservation of kidney function. CD80 (B7-1) can be expressed on injured podocytes, and administration of abatacept (modified CTLA4-Ig based on a natural ligand to CD80) has been associated with sustained normalization of urinary protein excretion and maintenance of glomerular filtration rate in experimental and clinical settings.

Methods

In this report, we describe the rationale for and design of a randomized, placebo-controlled, clinical trial of abatacept in patients with treatment-resistant nephrotic syndrome caused by focal segmental glomerulosclerosis or minimal change disease. The design is a hybrid of a parallel-group and crossover design (switchover) with the primary objectives assessed in the first period of the study and the secondary objectives assessed using data from both periods. All participants will receive the active agent in 1 of the periods. The duration of treatment will be 4 months per period.

Results

The primary outcome will be improvement in nephrotic-range proteinuria to subnephrotic range, that is, reduction from baseline to 4 months in urine protein:creatinine ratio ≥ 50% and to a level < 3. The projected sample size is 90 patients, which has 80% power to detect a treatment difference of 28%.

Conclusion

This study advances efforts to validate CD80 as a therapeutic target for treatment-resistant nephrotic syndrome, and implements a precision medicine-based approach to this serious kidney condition in which the selection of a therapeutic agent is guided by the underlying disease mechanism operating in individual patients.

Selection of Patients for Initial Clinical Trials of Solid Organ Xenotransplantation

Several groups have reported extended survival of genetically engineered pig organs in nonhuman primates, varying from almost 10 months for life-supporting kidney grafts and more than 2 years for non-life-supporting heart grafts to less than 1 month for life-supporting liver and lung grafts. We have attempted to define groups of patients who may not have an option to wait for an allograft. These include kidney, heart, and lung candidates who are highly-allosensitized. In addition, some kidney candidates (who have previously lost at least 2 allografts from rapid recurrence of native kidney disease) have a high risk of further recurrence and will not be offered a repeat allotransplant. Patients with complex congenital heart disease, who may have undergone previous palliative surgical procedures, may be unsuitable for ventricular assist device implantation. Patients dying of fulminant hepatic failure, for whom no alternative therapy is available, may be candidates for a pig liver, even if only as a bridge until an allograft becomes available. When the results of pig organ xenotransplantation in nonhuman primates suggest a realistic potential for success of a pilot clinical trial, highly selected patients should be offered participation.

Recurrent Nephrotic Syndrome After Renal Transplant in Children

OBJECTIVES

Recurrent disease occurs in around 30% of children transplanted for steroid-resistant nephrotic syndrome. Its precipitating risk factors have rarely been studied in the Middle East. The aim of our study was to determine what characterizes posttransplant recurrence of nephrotic syndrome in Syrian children.

MATERIALS AND METHODS

We performed a retrospective analysis of 12 nephrotic children who received 1 renal allograft at the Kidney Hospital in Damascus from 2002 to 2013.

RESULTS

Native kidney biopsy results showed focal segmental glomerulosclerosis in 9 of 10 patients. Four patients had 1 or more sibling affected with nephrotic syndrome, and the remaining patients were labeled as having sporadic disease. Genetic screening for NPHS2, NPHS1, and Wilms tumor gene (WT1) mutations were done for 6 patients, and 1 novel homozygous NPHS2 mutation was identified in 1 patient. All patients received transplants from living donors. Four patients had recurrence of initial disease after transplant (overall recurrence rate of 33%). However, 1 patient showed complete and spontaneous remission 20 months after transplant; As expected, the patient with NPSH2 mutation had no recurrence. Patients with sporadic disease showed risk of recurrence 5 times higher than patients with familial disease (P = .24). Interestingly, all recurrent cases had received a kidney from a related donor and were initially classified as having sporadic disease. Although not statistically significant, the risk of recurrence from related donor grafts was 6.75 times higher than from unrelated donors (P = .16). To the best of our knowledge, this observation, the first of its kind, has never been investigated or pointed out in the literature.

CONCLUSIONS

Further research is needed to confidently determine whether living related donor grafts are associated with increased incidence of recurrence of nephrotic syndrome.

The role of plasma exchange in treating post-transplant focal segmental glomerulosclerosis: A systematic review and meta-analysis of 77 case-reports and case-series

Background

Evidence on the role of plasma exchange for treating recurrent post-transplant focal segmental glomerulosclerosis (FSGS) comes largely from individual cases and uncontrolled series. We conducted a systematic review and meta-analysis to estimate the remission rate after treatment with plasma exchange, and to determine if remission varied with patient or treatment characteristics.

Methods

We searched MEDLINE, EMBASE, Science Citation Index Expanded, and the Conference Proceedings Citation Index (Science and BIOSIS) for studies of patients with post-transplant recurrent FSGS who were treated with plasma exchange after recurrence (1950–2012). Of 678 studies screened, 77 met our inclusion criteria: 34 case reports (45 patients) and 43 case series (378 patients). We extracted patient-level data from each study and used random-effects models to calculate remission, defined as proteinuria <3.5 g/day (partial) or <0.5 g/day (complete).

Results

The overall remission rate in 423 patients with outcome data was 71 % (95 % CI: 66 % to 75 %). In 235 patients with data on age, remission was similar for adults and children: 69.1 % (95 % CI: 59.6 % to 77.2 %) and 70.2 % (95 % CI: 61.1 % to 77.9 %). Males were more likely to achieve remission (OR = 2.85; 95 % CI: 1.44 to 5.62) and patients treated within 2 weeks of recurrence showed a trend towards higher likelihood of remission (OR = 2.16; 95 % CI: 0.93 to 5.01). Proteinuria >7 g/day at recurrence was inversely associated with remission (OR = 0.43; 95 % CI: 0.19 to 0.97). Age and type of kidney transplant (living vs. deceased) did not associate with remission.

Conclusion

In this systematic review of patients with recurrent post-transplant FSGS, 71 % of patients achieved full or partial remission after treatment with plasma exchange; however, extensive missing data and lack of a control group limit any conclusions on causality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0322-7) contains supplementary material, which is available to authorized users.

Recurrence and Treatment after Renal Transplantation in Children with FSGS

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage renal disease and a common pathologic diagnosis of idiopathic nephrotic syndrome (NS), especially in steroid-resistant cases. FSGS is known to recur after kidney transplantation, frequently followed by graft loss. However, not all patients with FSGS suffer from recurrence after kidney transplantation, and genetic and secondary FSGS have a negligible risk of recurrence. Furthermore, many cases of recurrence achieve remission with the current management of recurrence (intensive plasmapheresis/immunosuppression, including rituximab), and other promising agents are being evaluated. Therefore, a pathologic diagnosis of FSGS itself should not cause postponement of allograft kidney transplantation. For patients with a high risk of recurrence who presented with classical symptoms of NS, that is, severe edema, proteinuria, and hypoalbuminemia, close monitoring of proteinuria is necessary, followed by immediate, intensive treatment for recurrence.

Renal and Hematological Effects of CLCF-1, a B-Cell-Stimulating Cytokine of the IL-6 Family

CLCF-1 is a cytokine known for B-cell stimulation and for neurotrophic properties. We have identified CLCF-1 as a potential injurious factor in the human renal disease focal segmental glomerulosclerosis (FSGS). We investigated its effects on renal cells and renal function in in vitro and in vivo studies. Methods include measurement of the effect of CLCF-1 on phosphorylation of target molecules of the JAK/STAT pathway, on cytoskeleton and cell morphology in cultured podocytes, on albumin permeability of isolated rat glomeruli, and on tissue phosphorylation and urine albumin after acute or chronic CLCF-1 injection. In addition, cell sorting was performed to determine the presence of cells expressing CLCF-1 in spleen and bone marrow of normal mice and the effect of CLCF-1 infusion on splenic B-cell populations. CLCF-1 increased phosphorylation of STAT3 in multiple cell types, activated podocytes leading to formation of lamellipodia and decrease in basal stress fibers, increased glomerular albumin permeability, and increased STAT3 phosphorylation of peripheral blood cells and renal cortex. CLCF-1 increased urine albumin/creatinine ratio in mice and increased B-cell expression of IgG in mouse spleen. We conclude that CLCF-1 has potentially important systemic effects, alters podocyte function, and may contribute to renal dysfunction and albuminuria.