Update on treatment of immunoglobulin A nephropathy

Corticosteroids in the treatment of IgA nephropathy: lessons from the TESTING trial

IgA nephropathy (IgAN), the most common form of primary glomerulonephritis, is mainly observed in young adults and children. Clinical and basic studies indicate the role of immunity in IgAN pathogenesis; however, corticosteroid therapy has been controversial in past decades. The TESTING study, initiated in 2012, is an international, multicenter, double-blinded, randomized, placebo-controlled trial that aimed to evaluate oral methylprednisolone's safety and long-term efficacy under conditions of optimized supportive treatment in patients with IgAN whose risk of progression is high. After a decade of effort, the successful completion of the TESTING study showed that a 6- to 9-month course of oral methylprednisolone is an effective regimen to protect kidney function in high-risk patients with IgAN, but also demonstrated safety concerns. Compared with the full-dose regimen, the reduced-dose regimen was reported to be beneficial, with successfully increased safety. Overall, the TESTING trial provided more data regarding the treatment dosage and safety of corticosteroids, a cost-effective therapy, in IgAN, which have important implications for pediatric patients with IgAN. With a deeper understanding of the disease pathogenesis of IgAN, ongoing studies of novel therapeutic regimens would help further optimize the benefit-risk ratio.

Comparison between hydroxychloroquine and systemic corticosteroids in IgA nephropathy: a two-year follow-up study

BACKGROUND

Hydroxychloroquine (HCQ) is recommended as a treatment for IgA nephropathy (IgAN) to control proteinuria. The long-term effects of HCQ compared to systemic corticosteroid therapy remain unclear.

METHODS

We conducted a retrospective case‒control study at Peking University First Hospital. Thirty-nine patients with IgAN who received HCQ for at least 24 months without corticosteroids (CSs) or other immunosuppressive agents were included. Thirty-nine matched patients who received systemic CS therapy were selected using propensity score matching. Clinical data over a 24-month period were compared.

RESULTS

In the HCQ group, the level of proteinuria decreased from 1.72 [1.44, 2.35] to 0.97 [0.51, 1.37] g/d (-50.5 [-74.0, -3.4] %, P < 0.001) at 24 months. A significant decline in proteinuria was also found in the CS group, but no significant differences were found between the HCQ group and CS group in the levels of proteinuria (0.97 [0.51, 1.37] vs. 0.53 [0.25, 1.81] g/d, P = 0.707) and change rates (-50.5% [-74.0%, -3.4%] vs. -63.7% [-78.5%, -24.2%], P = 0.385) at 24 months. In addition, the decline rates of eGFR between the HCQ and CS groups were comparable (-7.9% [-16.1%, 5.8%] vs. -6.6% [-14.9%, 5.3%], P = 0.758). More adverse events were observed in the CS group.

CONCLUSIONS

Long-term use of HCQ can maintain stable renal function with minimal side effects. In patients who cannot tolerate corticosteroids, HCQ might be an effective and safe supportive therapy for IgAN.

Randomized Phase II JANUS Study of Atacicept in Patients With Immunoglobulin A Nephropathy and Persistent Proteinuria

Introduction

Patients with IgA nephropathy (IgAN) and persistent proteinuria are at risk of progression to kidney failure. Atacicept is a novel B-cell–targeted immunomodulator, shown to reduce immunoglobulin levels in patients with autoimmune diseases.

Methods

JANUS (NCT02808429) was a phase II study that assessed the safety, pharmacodynamic effects, and efficacy of atacicept in patients with IgAN and proteinuria ≥1 g/d or 0.75 mg/mg on 24-hour UPCR despite maximal standard of care therapy.

Results

A total of 16 patients were randomized 1:1:1 to placebo (n = 5), atacicept 25 mg (n = 6), or atacicept 75 mg (n = 5) once weekly using subcutaneous injection. Twelve (75%) completed ≥48 weeks of treatment; 8 (50%) completed 72 weeks of treatment and the 24-week safety follow-up period. Fourteen patients reported treatment-emergent adverse events (TEAEs). Most TEAEs were mild or moderate in severity. Three patients (placebo n = 1; atacicept 25 mg n = 2) reported serious TEAEs, none of which were treatment related. Dose-dependent reductions in IgA, IgG, IgM, and galactose-deficient (Gd)-IgA1 with atacicept at week 24 were maintained to week 72. Early reduction in proteinuria was observed at week 24 with atacicept. Renal function progressively declined with placebo but remained stable under exposure to atacicept.

Conclusion

Atacicept has an acceptable safety profile in patients with IgAN and is effective at reducing the levels of pathogenic factor Gd-IgA1, with potential improvements in proteinuria and renal function.

Efficacy and Safety of Immunosuppressive Monotherapy Agents for IgA Nephropathy: A Network Meta-Analysis

Background: The efficacy and safety of immunosuppressive monotherapy agents were evaluated for immunoglobulin A nephropathy (IgAN) using a network meta-analysis approach. Methods: Randomized controlled trials (RCTs) published prior to October 1, 2019, using immunosuppressive agents for treating IgAN, were systematically searched in PubMed, Embase, Cochrane Library, and Web of Science databases. Relative risks (RRs) or standard mean differences with 95% confidence intervals (CIs) were estimated using the random-effects model. The primary outcomes were clinical remission, end-stage renal disease (ESRD), and serious adverse events (SAEs). The secondary outcomes were urinary protein excretion and serum creatinine. Results: Twenty-five RCTs with 2,005 participants were deemed eligible. Six medications were evaluated: corticosteroids, mycophenolate mofetil (MMF), tacrolimus (TAC), cyclosporine, leflunomide, and hydroxychloroquine (HCQ). Steroids (RR 1.50, 95% CI 1.17-1.93), MMF (RR 2.05, 95% CI 1.15-3.65), TAC (RR 3.67, 95% CI 1.06-12.63), and HCQ (RR 3.25, 95% CI 1.05-10.09) significantly improved clinical remission rates compared to supportive care alone. Only steroids reduced the risk of ESRD (RR 0.35, 95% CI 0.12-0.98); however, there were significantly more SAEs than in the control group (RR 2.90, 95% CI 1.37-6.13). No significantly different effects in serum creatinine levels were found among the therapies. MMF showed no significant improvement in remission when excluding studies with a follow-up of fewer than 2 years in the sensitivity analysis (RR 1.41, 95% CI 0.40-4.92). The effect of TAC in the decrease of proteinuria was reversed after discontinuing medication for 3 months; the long-term effects of HCQ could not be evaluated due to the short follow-up duration. Conclusion: Corticosteroids might induce remission and increase renal survival in IgAN; however, adverse reactions should be taken into consideration. MMF, TAC, and HCQ might improve the remission of proteinuria when treating IgAN, but showed no superiority compared to steroids, and the long-term effects require further study.

Effect of hydroxychloroquine in patients with IgA nephropathy with insufficient responses to immunosuppressive therapy: a retrospective case-control study

Background

Hydroxychloroquine (HCQ) is a well-known immunomodulator that was recently used in immunoglobulin A (IgA) nephropathy (IgAN) due to its antiproteinuric effects. We investigated the effects of HCQ in patients with IgAN whose proteinuria remained above 1 g/d after conventional immunosuppressive (IS) therapy.

Methods

This study was a retrospective case-control study. Twenty-six patients with IgAN who received HCQ and had insufficient responses to IS therapy (corticosteroid (CS) therapy with/without IS agents) were included. Twenty-six matched historical controls who received conventional IS therapy were selected using propensity score matching. The clinical data from 6 months were compared.

Results

Proteinuria at baseline was comparable between the “IS therapy plus HCQ” and “conventional IS therapy” groups (2.35 [interquartile range (IQR), 1.47, 2.98] vs. 2.35 [IQR, 1.54, 2.98] g/d, p = 0.920). A significant reduction in proteinuria was noted in IgAN patients with HCQ treatment (2.35 [IQR, 1.47, 2.98] vs. 1.10 [IQR, 0.85, 1.61] g/d, p = 0.002). The percent reduction in proteinuria at 6 months was similar between the two groups (− 39.81% [− 66.26, − 12.37] vs. -31.99% [− 67.08, − 9.14], p = 0.968). The cumulative frequency of patients with a 50% reduction in proteinuria during the study was also comparable between the two groups (53.8% vs. 57.7%, p = 0.780). No serious adverse events (SAEs) were observed during the study.

Conclusions

Use of HCQ achieved has similar reduction in proteinuria compared to conventional IS therapy in patients with IgAN who had insufficient responses to IS therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02141-9.

The therapeutic effect of dendritic cells expressing indoleamine 2,3-dioxygenase (IDO) on an IgA nephropathy mouse model

OBJECTIVE

IgA nephropathy (IgAN) is one of the most common glomerulonephritis in the world, especially in Asian population. IgAN usually progresses slowly, but it is still an important cause of chronic renal failure. IgAN is characterized by abnormal increase of IgA1 level and deposition in mesangium. At present, there is no specific treatment.

MATERIALS AND METHODS

Previous reports have shown that DC cells expressing immunosuppressive factors can significantly reduce the symptoms of arthritis in arthritis models. Indoleamine 2,3-dioxygenase (IDO) is an important tryptophan degrading enzyme and an important factor regulating immunotolerance. DC expressing functional IDO can inhibit effector T cells by consuming essential tryptophan and/or producing toxic metabolites and promoting the differentiation of Treg cells, which exhibits immunosuppressive effect. In this study, we constructed a IgAN mouse model. The mature DC cells overexpressing IDO were induced in vitro and transfused back to IgAN mice to observe their effects on inflammation and renal injury.

RESULTS

The results showed that overexpression of IDO did not affect the maturation of DC cells. The proportion of CD3 + CD4 + and CD3 + CD8 + cells decreased significantly and the proportion of CD4 + CD25 + Foxp3 + cells increased significantly in kidney tissue of IgAN mice after the reinfusion of IDO-expressing DC. The contents of IL-2, IL-4, IL-6, and IL-17A in kidney tissue of IgAN mice also decreased significantly, the damage of kidney tissue was alleviated, ACR was decreased, collagen fibre content in kidney tissue was decreased, and IgA deposition in glomerular mesangium was decreased in IgAN mice.

CONCLUSIONS

It has the potential to treat IgAN by upregulating the expression of IDO in DC cells by genetic engineering and reinfusion into vivo.