Biopsy-confirmed IgA Nephropathy Research Articles

High systemic inflammatory response index (SIRI) is an independent risk factor for poor outcome in IgA nephropathy patients.

The systemic inflammatory response index (SIRI), a straightforward and easily accessible measure of inflammation and prognosis, has drawn more attention lately. It is unknown, however, if SIRI is important for IgA nephropathy (IgAN) patients' outcomes. To better clarify these concerns, we conducted this investigation. This retrospective study involved 981 patients with biopsy-confirmed IgAN from West China Hospital of Sichuan University between 2008 and 2019. The patients were divided into two groups based on the SIRI's optimal cut-off value calculated by the X-tile: the low SIRI group (SIRI ≤ 0.63, n = 312) and the high SIRI group (SIRI > 0.63, n = 669). Basic clinical characteristics at the time of renal biopsy were evaluated, and the relationship between SIRI and the combined endpoint was analyzed. We also used the Cox proportional hazard model and Kaplan‒Meier curve to evaluate the renal prognosis of IgAN. A total of 981 IgAN patients were included. During a median follow-up period of 56.7months (36.8-80.4months), 122 patients progressed to the combined endpoint (12.4%). Patients were divided into a low SIRI group (SIRI ≤ 0.63, n = 312) and a high SIRI group (SIRI > 0.63, n = 669) according to the optimal cut-off value of the systemic inflammatory response index (SIRI). Further analysis showed that a higher SIRI value was significantly associated with the risk of IgAN patients reaching the composite endpoint (HR 1.62, 95% CI 1.02-2.56, p = 0.041). High SIRI is a significant and independent risk factor for renal disease progression in IgAN patients.

Serum IgA/C3 ratio: a useful marker of disease activity in patients with IgA nephropathy.

High serum IgA and low serum C3 levels resulting from lectin and alternative pathway activation might be related to IgA nephropathy (IgAN) progression and exacerbation. This study examined whether the serum IgA/C3 ratio can serve as an IgAN progression marker. (1) This nationwide multicenter retrospective study in Japan included 718 patients with biopsy-confirmed IgAN. The patients whose serum creatinine levels at the time of renal biopsy had doubled were defined as having disease progression. (2) Furthermore, to investigate the pathological significance of a reduction in serum IgA/C3 ratio, we reviewed 63 patients whose serum IgA and C3 data at the end of the observation period were obtained. (1) A Kaplan-Meier analysis of the patients with IgAN revealed that the group with a high serum IgA/C3 (≥ 3.3) had a significantly worse renal outcome. In a multivariate analysis of eGFR ≥ 60mL/min per 1.73m2 at the time of biopsy, poor renal outcome was significantly predicted by a serum IgA/C3 ratio of ≥ 3.3. (2) A 15% reduction in the change of serum IgA/C3 ratio was associated with a significantly higher percentage of complete remission of proteinuria. Among the four groups divided by treatment, both the serum IgA/C3 ratio and proteinuria were reduced only in the tonsillectomy and steroid pulse group. The serum IgA/C3 level might reflect the disease activity and be a potent surrogate marker of therapeutic efficacy in patients with IgAN.

#388 IONIS-FB-LRx, an antisense oligonucleotide to complement factor B for treatment of IgA nephropathy

Abstract Background and Aims Pathogenesis of IgA nephropathy (IgAN) is known to be dependent upon multiple factors, one being the complement system. Since overactivity of the complement Alternative Pathway (AP) has been proposed to contribute to pathogenesis of IgAN, it has been hypothesized that a reduction of AP activity would improve proteinuria. IONIS-FB-LRx, (ISIS696844, RO7434656), is an investigational antisense oligonucleotide targeting complement factor B (CFB) mRNA and reduces CFB production in the liver. We have previously demonstrated that administration of IONIS-FB-LRx lowered the production of CFB, a required component of the AP, and led to reduction of AP and reduction in proteinuria in IgAN patients (2023 ASN Abstract#SA-PO926, N = 13 patients). Current abstract provides an update to our previous report extending results to 19 patients treated with IONIS-FB-LRx. Method An exploratory, single-arm, multi-national open-label Ph2 study (NCT04014335) recruited patients with biopsy-confirmed IgAN, proteinuria >1.5 g/d, eGFR >40 mL/min/1.73 m2, and hematuria despite maximum tolerated RAAS blockade and/or stable dose of SGLT-2 inhibitor for a minimum of 6 months. Study drug was administered at Weeks 1, 3, and 5, and then every 4 weeks through Week 25 (Cohort A) and at Week 1 and then every 4 weeks through Week 25 (Cohort B). Primary outcome was change in 24-hr proteinuria at Week 29 (4 weeks after last dose) compared to baseline (BL). Results 19 patients have completed study to date (13Nov2023), 25-62 yr, 42% Female, 11 Asian, and 8 White. Median 24-hr UPCR at BL was 1.56 g/g (IQR 1.23, 2.33 g/g). At Week 29, a 45% geometric mean ratio reduction was observed. There was little change in eGFR at Week 29 compared to BL (mean ± SD; BL 72 ± 22; Week 29 74.6 ± 20 mL/min/1.73 m2). The drug demonstrated an acceptable safety profile with no Treatment Emergent SAEs; the only clinically meaningful laboratory finding was reversible and transient ALT elevation without a change in bilirubin. All patients completed the study and one patient discontinued study drug after 4 months to initiate SGLT-2 inhibitors. That patient experienced a 38% reduction in 24-hr UPCR collected 3 weeks (Week 27) after the last dose of IONIS-FB-LRx, but prior to use of SGLT-2 inhibitors. Conclusion This Ph2 open-label study provides continuing clinical evidence that IONIS-FB-LRx reduces complement levels and proteinuria in patients with IgAN, supporting Ph3 development (NCT05797610) to determine the potential of IONIS-FB-LRx to reduce the progression of IgAN.

#1342 Updated results from the RUBY-3 study of povetacicept, an enhanced dual BAFF/APRIL antagonist, in autoantibody-associated glomerulonephritis

Abstract Background and Aims Inhibition of BAFF and/or APRIL has shown promise in IgA nephropathy (IgAN), systemic lupus erythematosus (SLE), lupus nephritis (LN), and primary membranous nephropathy (pMN), and has the potential to exert a disease-modifying effect. Povetacicept (ALPN-303) is an Fc fusion protein of a variant TACI domain engineered for more potent dual BAFF/APRIL inhibition than wild-type TACI or anti-BAFF or anti-APRIL antibodies. In a previous report, povetacicept 80 mg every 4 weeks was initially well tolerated and demonstrated promising, clinically meaningful reductions in urine protein to creatinine ratio (UPCR) and Gd-IgA1 in participants with IgAN (Tumlin J, et al. Poster TH-PO1125 presented at ASN 2023). Updated data are reported here. Method RUBY-3 is an open-label, multiple ascending dose, phase 1b/2a study of povetacicept 80 or 240 mg administered subcutaneously once every 4 weeks. Eligible participants are aged ≥18 years with biopsy-confirmed IgAN, LN, or pMN and on maximally tolerated ACE inhibitor/ARB therapy, with well-controlled blood pressure, and disease-specific immunosuppressive therapy where applicable. The primary objective is safety; secondary objectives include pharmacokinetics, pharmacodynamics, immunogenicity, biomarkers, and efficacy. Results As of 1 Dec 2023, 12 participants with IgAN have enrolled and received povetacicept 80 mg, with 7 (58%) having received ≥24 weeks of treatment. Povetacicept continues to be well tolerated, with the majority of treatment-emergent adverse events being of low grade. There have been no incidences of severe hypogammaglobulinemia (IgG <3 g/L) or severe infections. Povetacicept 80 mg was associated with a UPCR reduction of 52.6% at 24 weeks (n = 7). Reductions in Gd-IgA1, stable renal function, and pharmacodynamically expected decreases in immunoglobulin levels were also observed. Additional results from the 80 mg cohort with longer duration of follow-up, as well as initial results from the 240 mg dosing cohort, are planned to be presented. Conclusion Povetacicept remains well tolerated with multiple dosing and continues to demonstrate very promising activity in IgAN, strongly supporting further study in IgAN as well as other glomerulonephritis and autoantibody-associated diseases.

#162 Single-nucleus RNA-seq of biopsy-confirmed IgA nephropathy reveals cell-specific transcriptomic alteration

Abstract Background and Aims Single-nucleus RNA-seq (SnRNA-seq) is a valuable method for identifying cell-specific transcriptomic alterations in kidney cells. Our objective was to investigate SnRNA-seq data from biopsy-confirmed IgA nephropathy (IgAN) cases and identify cell-specific alterations in the transcriptome. Method We collected snap-frozen kidney biopsy tissues from 6 cases of IgA nephropathy (IgAN) and 7 nephrectomy control cases. The disease control group included 3 cases of diabetic kidney disease, 6 cases of minimal change disease, and 6 PLA2R-Ab positive membranous nephropathy cases. SnRNA-seq was performed on the kidney tissues, and kidney cells were identified in the dataset through UMAP clustering. We investigated differences in the proportion of kidney cell types and identified differentially expressed genes (DEGs). Additionally, we searched for representative gene loci previously reported in a multiethnic genome-wide association study (GWAS). Results We successfully collected transcriptomic profiles of >50 000 cells from IgAN, with a considerable enrichment of intraglomerular cells. The DEG analysis revealed a high number of DEGs in mesangial cells, fibroblasts, and vascular smooth muscle cells in the IgAN transcriptome compared to the nephrectomy and disease control cases. In the gene set enrichment analysis, the epithelial-mesenchymal transition pathway was enriched in the glomerular cells of IgAN. Furthermore, among various GWAS loci, ETS1 was the gene significantly highly expressed in the mesangial cells of IgAN, consistent across the compared control groups. Conclusion This investigation represents the largest SnRNA-Seq profiling of IgAN kidney cells to date. We identified notable enriched cell-specific pathways in IgAN. ETS1 may be a kidney-indwelling causal factor for IgAN pathophysiology, considering its notable significance in both previous GWAS results and the current SnRNA-Seq data.

#145 Subgroup and secondary endpoint evaluation of a phase 2 randomized placebo-controlled trial of ravulizumab in IgA nephropathy

Abstract Background and Aims The pathogenesis of IgA nephropathy (IgAN) involves immune complex deposition and activation of the complement system, causing formation of the terminal pathway components C5a and C5b-9, leading to inflammation and glomerular damage. Elevated levels of activated C3 in plasma are associated with proteinuria and renal function decline in patients with IgAN [1]; mesangial C3 deposition is also associated with progression of disease [2]. Ravulizumab is a humanized monoclonal antibody that immediately and completely inhibits complement component C5. Primary endpoint (week 26) data from the phase 2 randomized controlled trial (RCT) (NCT04564339) were previously reported and demonstrated a 30% and 33% treatment effect of ravulizumab compared to placebo on 24-hour urine protein and 24-hour urine protein-to-creatinine ratio (UPCR) reduction, respectively [3]. This analysis reports prespecified subgroup and secondary endpoints as well as post hoc exploration of treatment response by baseline serum C3 and C4 quartiles through week 26. Method The SANCTUARY RCT evaluated ravulizumab (IV; weight-based dosing Q8W) vs placebo in adults with primary IgA nephropathy. Randomized patients (2:1) were stratified by mean proteinuria (1–2 vs >2 g/day). Patients (18–75 years) with biopsy-confirmed IgA nephropathy, proteinuria ≥1g/day, estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2, and on stable maximally tolerated renin angiotensin inhibition were enrolled. The primary endpoint was proteinuria reduction at week 26 based on 24-hour urine collection. Secondary endpoints at week 26 included the proportion of patients with >50% reduction in proteinuria (absolute urine protein) and the percentage with <1g/day proteinuria. The percentage change in proteinuria (absolute urine protein) among subgroups of sex, race, duration of disease, baseline proteinuria and eGFR, and baseline serum C3 and C4 levels were also evaluated, as were safety data. Results 66 patients entered the 26-week initial evaluation period (n = 43, ravulizumab arm; n = 23, placebo arm); 71.2% were White and 21.2% were Asian. Overall, 41.5% and 18.2% of ravulizumab- and placebo-treated patients, respectively, achieved >50% proteinuria reduction (Fig. 1). Proteinuria reduction to <1g/day was achieved in 26.8% and 18.2% in the ravulizumab and placebo arms, respectively. Subgroup analysis indicated a treatment effect across subgroups of sex, race, disease duration, and baseline proteinuria and eGFR (Fig. 2). With ravulizumab, there were reductions of 41.9% and 41.0% in proteinuria for those with the lowest quartile of baseline serum C3 and C4, respectively. Similarly, reductions of 40.4% and 40.8% were observed in those with baseline serum C3 and C4 levels above the lowest quartile. In the ravulizumab arm, two patients had low serum C3 at baseline and there were no patients with low serum C4 at baseline; there was no change in mean serum C3 and C4 levels over time. Treatment with ravulizumab was well-tolerated. Conclusion In this phase 2 trial of ravulizumab in IgAN, proteinuria was significantly reduced with ravulizumab vs placebo through week 26. A reduction in proteinuria was also observed across subgroups of patients. As is typical in IgAN, serum C3 and C4 levels at baseline were normal, and there was no difference in proteinuria reduction by baseline serum C3 and C4 levels with ravulizumab through 6 months.

#1422 Exploring BAFF, APRIL, and clinical characteristics in IgA nephropathy: a decade-long study in the Bulgarian population

Abstract Background and Aims IgA nephropathy (IgAN) represents a significant global health concern, contributing substantially to chronic kidney disease and renal failure. Despite its widespread impact, the Bulgarian population lacks comprehensive epidemiological data and specific biomarkers for IgAN. This decade-long retrospective study, conducted at a tertiary Nephrology Clinic in Bulgaria, aims to explore the clinical characteristics and serum levels of BAFF and APRIL in biopsy-confirmed IgAN patients and healthy controls. Method The study includes 125 biopsy-confirmed IgAN patients and 30 healthy controls. Notably, 70.4% of IgAN patients were male, with an average age of 35.94 ± 11.91 years. Baseline characteristics reveal advanced disease stages at diagnosis, possibly linked to delayed biopsy (24.22 ± 32.9 months from initial symptoms) and the absence of a screening program. Analyses of serum biomarkers (C3, BAFF, and APRIL) are conducted to identify any significant variations between IgAN patients and healthy volunteers. Results The average baseline estimated glomerular filtration rate (eGFR) was 61.78 ± 27.72 ml/min/1.73 m², with a mean serum creatinine of 126 ± 67.83 μmol/l at the time of kidney biopsy. Among the patients, 51.2% had an eGFR below 60 ml/min, indicating CKD stage 3 or worse according to the KDIGO classification Binary logistic regression analysis identifies anemia as a significant contributor to disease progression, with a risk influence approximately 3.3 times higher for GFR decline over time. Anemia emerges as a crucial predictor for serum creatinine doubling, carrying a higher risk than hyperuricemia. Analyses of C3 (p = 0.658), BAFF (p = 0.432), and APRIL (p = 0.227), demonstrated no significant differences in their serum levels between IgAN patients and healthy volunteers. Conclusion This study provides comprehensive insights into IgAN in the Bulgarian population, addressing the dearth of epidemiological data and biomarkers. Anemia emerges as a significant predictor for disease progression, emphasizing its potential clinical relevance. However, C3, BAFF, and APRIL exhibit no notable variations, underscoring the need for additional biomarker exploration to enhance understanding of IgAN dynamics in this population.

#1522 Comparative analysis of clinical and pathological traits in IgA nephropathy with nephrotic range proteinuria based on serum albumin level

Abstract Background and Aims Presently, the clinical outcomes associated with IgA nephropathy exhibiting heavy proteinuria and the potential correlation between decreasing serum albumin levels and adverse prognosis have not been conclusively established. The present study was designed to elucidate the clinical and pathological characteristics of IgA nephropathy patients who present with nephrotic-range proteinuria, particularly in relation to serum albumin levels. Method This retrospective cohort study was conducted using data from biopsy-confirmed IgA nephropathy patients presenting with nephrotic-range proteinuria between 2017 and 2022 from eight university-affiliated hospitals in South Korea. Patients were stratified into two groups based on a serum albumin level of 3.0 g/dl. The study involved a comparative assessment of clinical and pathological characteristics across these two groups, as well as an evaluation of clinical prognosis with respect to the end-stage kidney disease (ESKD). Results The analysis included a total of 127 patients. Of these, 86 patients had a serum albumin level above 3.0 g/dl (designated as the preserved albumin group, or PA group), while 41 patients had levels below 3.0 g/dl (designated as the reduced albumin group, or RA group). The baseline characteristics of the two groups were found to be statistically similar. The mean age of the patients was 46.46 years, and 46.46% were male. In the laboratory findings, the RA group had significantly elevated erythrocyte sedimentation rate compared to the PA group. Additionally, total cholesterol and low-density lipoprotein-cholesterol levels were significantly higher in the RA group compared to the PA group. Proteinuria was observed to be significantly higher in the RA group. Pathological examinations demonstrated that in electron microscopy (EM) findings, the RA group exhibited a more pronounced diffuse foot process effacement. Over the course of one year, the trend in creatinine changes exhibited differences between the two groups over time (time x group interaction P = 0.002). Furthermore, it appeared that the reduction in the quantity of proteinuria was more substantial within the RA group (time x group interaction P = 0.001). During a median follow-up period of 25.22 months (ranging from 11.98 to 49.23 months), 14 patients (11.02%) in the PA group progressed to ESKD, compared with 10 patient (24.39 %) in the RA group. However, there was no statistically significant difference between the two groups in terms of progression to ESKD (P = 0.330). Conclusion In patients diagnosed with IgA nephropathy presenting with nephrotic-range proteinuria, a decline in serum albumin levels was associated with diffuse foot process effacement, and the decrease in serum albumin was not found to be associated with adverse prognosis.

Haemoglobin, albumin, lymphocyte, and platelet score as an independent predictor for renal prognosis in IgA nephropathy.

The haemoglobin, albumin, lymphocyte, and platelet (HALP) score, a convenient and composite laboratory biomarker, can reflect inflammation and systemic nutritional status. This study was performed to investigate the effect of the HALP score on the prognosis of patients with IgA nephropathy (IgAN). This is a retrospective single centre study that enrolled 895 biopsy-confirmed IgAN patients from June 2019 to June 2022 who were followed for more than 1 year. Kaplan-Meier curves and Cox regression analyses were performed to determine the relationship between HALP and adverse outcomes. The restricted cubic splines was used to identify the possible associations. The optimal cut-off value of HALP for renal poor outcome was identified by the area under the receiver operating characteristic curve (AUC). A total of 895 patients finally participated in the study and were divided into three groups (tertial 1-3) according to the baseline HALP score. More severe clinicopathologic features were observed in the lower HALP group, and Kaplan-Meier analysis showed patients in tertial 1 had a higher risk of kidney failure than the other groups (log-rank=11.02, P= 0.004). Multivariate Cox regression revealed that HALP score was an independent risk factor for renal prognosis in IgAN (adjusted HR: 0.967, 95% CI: 0.945-0.990, P = 0.006). The results of subgroup analysis suggested that HALP was more important in patients under the age of 50, BMI ≤ 23.9 and eGFR ≤ 90 mL/min/1.73 m2. The best cut-off HALP for renal survival was 38.83, sensitivity 72.1%, and specificity 55.9% (AUC: 0.662). Patients were further grouped according to HALP cut-off values and propensity matched. Multivariate Cox regression analysis revealed that HALP remained an independent predictor of IgAN in the matched cohort (HR 0.222, CI: 0.084-0.588, P=0.002). HALP is a novel and potent composite parameter to predict kidney outcome in patients with IgAN.

The efficacy and safety of hydroxychloroquine versus leflunomide in patients with IgA nephropathy: a single-center experience

PurposeTo date, our understanding of IgA nephropathy (IgAN) pathophysiology has remained incomplete; therefore, treatment remains largely empiric, and the efficacy and safety of immunosuppressants remain controversial. We aimed to assess the efficacy and safety of hydroxychloroquine and leflunomide therapy in a retrospective cohort of patients with IgAN.MethodsWe screened the IgAN registration database in our department, and a total of 159 kidney patients with biopsy-confirmed IgAN were enrolled, with 57 patients receiving hydroxychloroquine plus a renin-angiotensin system inhibitor (hydroxychloroquine group), 52 patients receiving leflunomide plus a renin-angiotensin system inhibitor (leflunomide group), and 50 patients receiving only a renin-angiotensin system inhibitor (renin-angiotensin system inhibitor-only group). Changes in proteinuria, hematuria, and the estimated glomerular filtration rate (eGFR), as well as adverse events, were analyzed during the follow-up period.ResultsAt the end of 6-month follow-up, proteinuria significantly decreased by 70.36 (57.54, 79.33)%, 57.29 (46.79, 67.29)% and 41.20 (25.76, 48.94)% in the hydroxychloroquine, leflunomide and renin-angiotensin system inhibitor-only groups, respectively, compared to baseline (all P values < 0.001). Hematuria significantly decreased by 71.07 (56.48, 82.47)% in the leflunomide group (P < 0.001). The eGFR improved by 3.72 ± 2.97%, 3.16 ± 2.00% and 1.91 ± 2.41%, respectively, in the hydroxychloroquine, leflunomide and renin-angiotensin system inhibitor-only groups, but without statistical significance. No serious adverse events occurred during the follow-up period.ConclusionBoth hydroxychloroquine combined with a renin-angiotensin system inhibitor and leflunomide combined with a renin-angiotensin system inhibitor were more effective than a renin-angiotensin system inhibitor alone in improving proteinuria in IgAN patients. Hydroxychloroquine was more effective in reducing proteinuria, and leflunomide showed superiority in reducing hematuria. Our results need to be verified in large-scale randomized controlled trials.Graphical abstract

COSMC expression as a predictor of remission in IgA nephropathy.

The impact of core 1,3-galactosyltransferase-specific molecular chaperon (COSMC) gene expression and methylation profile on clinical progression of IgA nephropathy (IgAN) is unclear. The aim of this study was to determine the clinical significance and the relation of the COSMC gene expression and methylation pattern with the progression of IgAN. Thirty-nine biopsy-confirmed IgAN patients, 11 healthy relatives and 20 healthy controls were recruited. The COSMC mRNA levels and methylation profile of COSMC gene promoter were measured using the quantitative real-time PCR. The galactose-deficient IgA1 (Gd-IgA1) levels were measured using ELISA in serum and cell culture supernatant. The effect of IL-4 and AZA on COSMC expression and methylation and the correlation of COSMC gene expression and methylation levels with baseline kidney function tests, histology and long-term outcomes were examined. The mean COSMC mRNA level was significantly lower, and serum Gd-IgA1 level was higher in IgAN patients compared with the control groups (p < 0.001, and p = < 0.001, respectively). The COSMC mRNA levels were correlated with intensity of hematuria (r = -0.41, p = 0.009), serum creatinine level (r = -0.37, p = 0.002) and eGFR (r = 0.36, p = 0.002). The COSMC methylation levels were correlated with age (r = 0.25, p = 0.04) and baseline eGFR (r = -0.326, p = 0.006). Twenty IgAN patients (51.3%) reached to complete (5, 12.8%) or partial remission (15, 38.5%) after a median of 34.5months (IQR, 13.75-71). In multivariable Cox regression analysis, COSMC mRNA expression (adjusted HR (aHR) 1.871, 95% CI 1.287-2.722, p = 0.001) and Oxford T score (aHR 0.355, 95% CI 0.146-0.859, p = 0.022) predicted the remission. COSMC mRNA level is a novel biomarker candidate to predict the remission in IgAN patients.

Alport syndrome: new advances in the last decade

Alport syndrome (AS) is a progressive hereditary nephritis that is often accompanied by sensorineural hearing loss and ocular abnormalities. It is inherited in three modes of X-linked (XLAS), autosomal recessive (ARAS), and autosomal dominant (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ARAS and ADAS are caused by those in COL4A3 or COL4A4. There is currently no curative treatment for AS; however, angiotensin-converting enzyme inhibitors (ACEi) can improve the outcome of AS. In the past decade, multiple studies have shown that early intervention with ACEi upon isolated microscopic hematuria or microalbuminuria could delay disease progression, and early diagnosis is crucial for early treatment. Therefore, a new classification of AS based on molecular diagnoses has been proposed, including the paradigm shift of re-classifying female “carriers” to “patients” and “thin basement membrane nephropathy” to “ADAS.” In addition, with the detection of COL4A mutations in some patients with biopsy-confirmed IgA nephropathy, focal segmental glomerulosclerosis, and chronic kidney disease of unknown origin, it is suggested that the phenotype of AS should be expanded. In this review, we highlight the landmark studies and guidelines published over the past decade and introduce strategies for early diagnosis and treatment to improve the outcomes of AS.

POS-546 EFFICACY AND SAFETY OF IPTACOPAN IN IgA NEPHROPATHY: RESULTS OF A RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROLLED PHASE 2 STUDY AT 6 MONTHS

No approved targeted therapies currently exist for IgA nephropathy (IgAN). Targeting the alternative complement pathway (AP) is an attractive therapeutic strategy given its role in the pathogenesis of IgAN. Iptacopan (LNP023) is a first-in-class, oral, potent and highly selective inhibitor of factor B of AP. This randomized, double-blind, dose-ranging, parallel-group adaptive design Phase 2 study (NCT03373461) enrolled patients with biopsy-confirmed IgAN (within the previous 3 years), urine protein-to-creatinine ratio (UPCR) ≥0.8 g/g or urine protein ≥0.75 g/24 h, and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2. Part 1 of the study enrolled patients for a 3-month treatment period; Part 2 of the study enrolled patients for a 6-month treatment period; both Parts comprised a 3-month treatment-free follow-up. Patients were randomized to one of the four iptacopan arms (10, 50, 100 [in Part 2 only], and 200 mg bid) or placebo. In this analysis, we report efficacy and biomarker data assessed at 6 months and treatment-emergent adverse events (AEs) assessed for the entire study duration. In addition to the pre-specified efficacy analysis of Part 2 at 6 months, Post hoc analyses combining data from Parts 1 and 2 were also performed. 46 and 66 patients were randomized in Parts 1 and 2, respectively. In Part 2, 58 patients completed 6 months of treatment. Demographic and baseline characteristics were generally well-balanced across all arms. The primary analysis yielded a statistically significant dose-response effect (1-sided p=0.038) of iptacopan versus placebo at 3 months, with maximal reduction in UPCR achieved with iptacopan 200 mg bid (23%; 80% CI: 8–34% using MCP-mod; Primary results were presented at 58thERA-EDTA Congress 2021 as late-breaking clinical trial ). UPCR continued to decrease between 3 and 6 months in the higher dosed iptacopan arms in Part 2, albeit with a wider 80% CI reflecting the smaller sample size. To allow better comparison with the primary analysis at 3 months, a Post hoc analysis of pooled data from Parts 1 and 2 was performed. The results indicated UPCR reduction from baseline up to 6 months in iptacopan 200 mg bid arm by up to 40% (80% CI: 16–53% using MCP-mod model) and at least 28% (80% CI: 3–46% using MMRM model) versus placebo (Figure 1). Sustained inhibition of AP biomarkers including plasma Bb, serum Wieslab, and urinary C5b-9 through 6 months was also observed with all doses of iptacopan above 10 mg bid (Figure 2). Iptacopan had a well-tolerated safety profile, with no deaths, no serious adverse events (SAEs) suspected to be treatment-related, and no serious infections caused by encapsulated bacteria. Iptacopan was well tolerated and led to continuous reduction in proteinuria and strong inhibition of AP activity through 6 months in patients with IgAN. These data are consistent with previous findings from the interim analysis at 3 months and support further evaluation of iptacopan in the ongoing Phase 3 APPLAUSE-IgAN trial (NCT04578834).

Clinical efficacy and safety of full-dose versus half-dose corticosteroids plus leflunomide for IgA nephropathy

BackgroundThe results of leflunomide (LEF) in patients with IgA nephropathy (IgAN) were inconsistent.MethodsA total of 149 kidney biopsy-confirmed IgAN patients with an estimated glomerular filtration rate (eGFR) ≥ 50 ml/min/1.73 m2 and protein excretion levels ≥0.75 g/d were enrolled, with 65 subjects receiving half-dose CS plus LEF (LEF group), and the 84 counterpart patients accepting full-dose corticosteroid (Full CS group). The primary outcomes included the complete remission (CR) rates and incidence of adverse events (AEs). The secondary outcomes were the overall remission (OR) rates and a combined event (eGFR reduced ≥30%, end-stage renal disease [ESRD], hemodialysis, peritoneal dialysis or kidney transplantation).ResultsDuring the 18 months of follow-up, the CR rates were 72 and 64% in the LEF and Full CS groups (P = 0.299), respectively. The proportion of patients with OR rates in the LEF group and Full CS group was 89% versus 75%, respectively (P = 0.027). Serious AEs were observed only in the Full CS group (P = 0.017). The incidences of total AEs (P = 0.036) and infections (P = 0.024) were lower in the LEF group than in the Full CS group.ConclusionsLEF combined with half-dose CS is superior to full-dose CS in the treatment of IgAN.

MO306IGA NEPHROPATHY: A 20 YEAR RETROSPECTIVE SINGLE CENTRE EXPERIENCE

Abstract Background and Aims IgA nephropathy is the most common glomerulonephritis worldwide. The clinical course is heterogeneous and not always easy to predict. As such, determining which patients to treat with immunosuppression has been the cause of much debate. Over recent years there has been a focus on risk prediction to help with treatment decisions (such as the widely validated International IgA Risk Prediction Tool). Here, we present a 20 year retrospective study from a single centre with the following aims: to describe the epidemiology of our cohort, to assess outcomes (such as progression to ESKD requiring RRT, mortality), and to determine if treatment choices have changed over time. Method We collected all cases of IgA nephropathy from our biopsy database between January 2020 and December 2019. This totalled 525 biopsies. Of these, a number were excluded from analysis, including transplant biopsies and repeat biopsies in the same patient. After exclusion, the original 525 biopsies were narrowed down to 452 patients for analysis. We collected demographic data for each patient, along with creatinine and proteinuria values over time, MEST-C scores, progression to ESKD, mortality, use of RAAS blockade and immunosuppressants. Initial analysis was performed using Excel. We plan to perform further multivariate Cox regression analysis to determine if there are associations with progression to ESKD such as degree of proteinuria, MEST-C scores and immunosuppression treatment. Results We identified 452 patients with biopsy confirmed IgA nephropathy at our centre between January 2000 and December 2019. 138 (30.5%) were female and 314 (69.4%) were male. The average age at time of biopsy was 45.7 years. Mortality over this period was 19.2% (87 patients). 126 (27.9%) progressed to ESKD requiring RRT, 6 (1.3%) required temporary dialysis whilst 313 (69.2%) did not require RRT. With regards to treatment, 329 (72.8%) were treated with RAAS blockade in comparison to 85 (18.8%) who were not (in 38 patients this was unclear). No immunosuppression was used in 349 (77.2%), whilst a combination of prednisolone; IV cyclophosphamide and prednisolone; and MMF and prednisolone was used in 97 (21.5%). Conclusion We present here a large single centre dataset of IgA nephropathy patients over a 20 year period. We show that there remains a significant risk of progression to ESKD over time. It is important to identify those patients most at risk of progression early on in their disease course so that optimal treatment can be initiated. Further analysis of this dataset will allow us to assess whether treatment strategies in recent years has had a beneficial effect on outcomes, and also to assess the correlation between MEST-C scores and treatment decisions.

A case presentation of an IgA nephropathy patient with Vogt-Koyanagi-Harada syndrome

BackgroundVogt-Koyanagi-Harada syndrome is a rare disease characterized by skin and eyelash bleaching, chronic granulomatous iridocyclitis and exudative retinal detachment, and aseptic meningitis and encephalopathy. IgA nephropathy complicated by Vogt-Koyanagi-Harada syndrome is very rare, even though they might have similar pathogeneses. Ocular lesions often are not examined when patients are diagnosed with IgA nephropathy, which affects the prognosis.Case presentationWe describe a 55-year-old male IgA nephropathy patient who was admitted with high fever and hematuria. Physical examination revealed impaired binocular vision with blurred vision, impaired hearing, and a congestive rash on the chest and back. Renal ultrasound examination showed no abnormalities. Laboratory examination showed that glomerulonephritis was complicated by infection, and anti-infection therapy was ineffective. Bilateral fluorescein angiography showed Vogt-Koyanagi-Harada syndrome. Further renal biopsy confirmed IgA nephropathy. Hormone shock therapy and cyclophosphamide adjuvant therapy were administered, and the patient’s symptoms improved.ConclusionFor the first time, we reported the case of simultaneous onset of IgA nephropathy and Vogt-Koyanagi-Harada syndrome, which is very rare. The onset of Vogt-Koyanagi-Harada syndrome is rapid and serious, while that of IgA nephropathy is relatively milder, making it easy for specialized doctors to neglect this condition. Doctors should be highly alert to the clinical concomitant occurrence of the two diseases with similar mechanisms, especially in the case of neurological defects and ocular symptoms in IgA nephropathy patients, since timely immunosuppressive treatment may improve the outcome of ocular diseases.

Predictive value of mesangial C3 and C4d deposition in IgA nephropathy

We aimed to determine the relative contribution of each complement (C3 and C4d) deposition to the progression of IgA nephropathy (IgAN). We enrolled a total of 380 patients with biopsy-confirmed IgAN. Mesangial deposition of C3(<2+ vs. ≥2+) and C4d(positive vs. negative) was evaluated by immunofluorescence staining and immunohistochemistry, respectively. Study endpoint was the composite of a 30% decline in eGFR or ESRD. The risk of reaching the primary outcome was significantly higher in patients having C3 ≥ 2+ and C4d(+) than in corresponding counterparts. Adding C3 deposition to clinical data acquired at kidney biopsy modestly increased the area under the receiver-operating characteristic curve, net reclassification improvement, and integrated discrimination improvement (IDI); adding C4d increased IDI only. In conclusion, mesangial C3 and C4d deposition was an independent risk factor for progression of IgAN. C3 showed better predictability than C4d, suggesting that lectin pathway alone has limited clinical prognostic value.

Serologic and Histologic Predictors of Long-Term Renal Outcome in Biopsy-Confirmed IgA Nephropathy (Haas Classification): An Observational Study.

Background and objective: The Haas classification of IgA nephropathy should be validated for Asian populations. More detailed and newer predictions regarding renal outcome of IgA nephropathy remains mandatory. Materials: We conducted a retrospective cohort study between January 2003 and December 2013. Clinical, Pathological, and laboratory data were all collected via available medical records. A Mann–Whitney U test was used for continuous variables and the Chi-square test was implemented for categorical variables. A Kaplan–Meier curve was put in place in order to determine patient survival and renal survival. The Youden index and Cox proportional hazard regression were used to investigate the possible factors for renal survival and predictive power. Results: All 272 renal biopsy-confirmed IgAN patients were enrolled for further studies. The univariate analysis showed that risk factors for poor renal outcome included stage 4–5 of Haas classification (HR = 3.67, p < 0.001), a poor baseline renal function (HR = 1.02 and p < 0.001 for higher BUN; HR = 1.14 and p < 0.001 for higher serum creatinine; HR = 0.95, p < 0.001 for higher eGFR), IgG ≤ 907 (HR = 2.29, p = 0.003), C3 ≤ 79.7 (HR = 2.76, p = 0.002), a higher C4 (HR = 1.02, p = 0.026), neutrophil-to-lymphocyte ratio > 2.75 (HR = 2.92, p < 0.001), and a platelet-to-lymphocyte ratio ≥ 16.06 (HR = 2.02, p = 0.012). A routine-checked markers, such as neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, in order to predict the renal outcome, is recommended. Conclusions: This is the first study to demonstrate that Haas classification is also useful for establishing predictive values in Asian groups. A lower serum IgG (≤907 mg/dL) and serum C3 (≤79.7 mg/dL) were both risk factors for poor renal outcome. Additionally, this is the first study to reveal that serum C4 levels, an NLR > 2.75 and a PLR > 16.06, S could suggest poor renal outcome.

Long noncoding RNA lnc-TSI inhibits renal fibrogenesis by negatively regulating the TGF-β/Smad3 pathway.

Transforming growth factor-β (TGF-β) is a well-established central mediator of renal fibrosis, a common outcome of almost all progressive chronic kidney diseases. Here, we identified a poorly conserved and kidney-enriched long noncoding RNA in TGF-β1-stimulated human tubular epithelial cells and fibrotic kidneys, which we termed TGF-β/Smad3-interacting long noncoding RNA (lnc-TSI). Lnc-TSI was transcriptionally regulated by Smad3 and specifically inhibited TGF-β-induced Smad3 phosphorylation and downstream profibrotic gene expression. Lnc-TSI acted by binding with the MH2 domain of Smad3, blocking the interaction of Smad3 with TGF-β receptor I independent of Smad7. Delivery of human lnc-TSI into unilateral ureteral obstruction (UUO) mice, a well-established model of renal fibrosis, inhibited phosphorylation of Smad3 in the kidney and attenuated renal fibrosis. In a cohort of 58 patients with biopsy-confirmed IgA nephropathy (IgAN), lnc-TSI renal expression negatively correlated with the renal fibrosis index (r = -0.56, P < 0.001) after adjusting for cofounders. In a longitudinal study, 32 IgAN patients with low expression of renal lnc-TSI at initial biopsy had more pronounced increases in their renal fibrosis index and experienced stronger declines in renal function at repeat biopsy at a mean of 48 months of follow-up. These data suggest that lnc-TSI reduced renal fibrogenesis through negative regulation of the TGF-β/Smad pathway.

Clinical value of systemic symptoms in IgA nephropathy with ANCA positivity

Our aim was to evaluate the pathogenic role of anti-neutrophil cytoplasmic antibodies (ANCAs) in patients with IgA nephropathy (IgAN). A total of 2390 patients with biopsy-confirmed IgAN were analyzed retrospectively. Thirty-five IgAN patients with ANCA and 40 IgAN patients without ANCA were enrolled. According to the Birmingham Vasculitis Activity Score (BVAS) items, the ANCA-positive patients were further divided into two subgroups which with or without systemic symptoms. The cumulative renal survival rate was calculated using Kaplan-Meier analysis. Comparisons between groups were made using the log rank test. Among the 35 ANCA-positive patients, 14 (40%) had systemic symptoms. Compared with ANCA-positive patients without systemic symptoms, ANCA-positive patients with systemic symptoms had a shorter duration of disease (1.0 [IQR, 0.3-6.8] vs. 6.0 [IQR, 2.0-21.0], P = 0.011); showed worse renal function with lower levels of eGFR (24.2 [IQR, 11.7-74.9] vs. 100.1 [IQR, 59.6-130.2] mL/min/1.73m2, P = 0.002), serum albumin (30.4 [IQR, 27.4-34.8] vs. 41.5 [IQR, 35.1-44.4] g/L, P = 0.001), and hemoglobin (96.1 ± 21.5 vs. 118.2 ± 22.4g/L, P = 0.006); and presented relatively higher incidences of rapidly deteriorating kidney function (28.6 vs. 0.0%, P = 0.039) and moderate-to-severe tubular atrophy (78.6 vs. 23.8%, P = 0.001). Kaplan-Meier analysis had shown that ANCA-positive patients with systemic symptoms had lower cumulative renal survival rate compared with both ANCA-positive patients without systemic symptoms and ANCA-negative patients (log rank = 14.40, P < 0.001). Evaluation of systemic symptoms is a simple, readily available clinical tool to predictive the pathogenic role of ANCA in IgAN.