Chronic nephrotoxicity limits successful use of Tacrolimus in the management of adult steroid-dependent minimal change disease

Rituximab in maintaining remission in adults with podocytopathy

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

METHODS

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

PRIMARY OUTCOME

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

RESULTS

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

CONCLUSION

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

Tacrolimus treatment in childhood refractory nephrotic syndrome: A retrospective study on efficacy, therapeutic drug monitoring, and contributing factors to variable blood tacrolimus levels

Tacrolimus, an immunosuppressive drug, was recommended by the 2012 KDIGO guidelines to treat nephrotic syndrome (NS) in children and adults. However, it has high interpatient pharmacokinetic variability and exposure levels should be monitored, although there are no specified target concentrations. This retrospective study aimed to review efficacy and safety after concomitant treatment with tacrolimus and prednisone, and to identify factors that contribute to the variable blood-trough-concentration-to-dose (C₀/Dose) ratio in children with refractory NS (RNS). A 6-month therapy induced complete or partial remission in 95% of patients. One-year follow-up indicated a high remission rate and low nephrotoxicity. Under maintenance dosages, approximately 95% of the C₀ values were 2-7 ng/mL. Body weight (BW), age, CYP3A5 polymorphisms were the factors affecting the C₀/Dose ratio. The C₀/Dose ratio in patients with a BW of <20 kg was 1.5-fold than that in patients with BW of ≥40 kg. Moreover, the C₀/Dose ratio in patients aged 1-≤6 and 6-≤12 years was significantly lower than that in patients aged 12-≤18 years, by 25% and 48%, respectively. There were no significant association between CYP3A5 genotyping and C₀/Dose ratio in younger children (1-≤6 years), rather than older children (6-≤18 years). In conclusion, routine CYP3A5 genotyping should be considered in children aged over 6 years and exposure levels (C₀) of 2-7 ng/mL may be feasible when tacrolimus is combined with low-dose prednisone to treat childhood RNS.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Rituximab as a front-line therapy for adult-onset minimal change disease with nephrotic syndrome

Minimal change disease (MCD) accounts for 15% of adult nephrotic syndrome (NS) cases. Adult-MCD patients may have more severe clinical features than pediatric patients. In children, Rituximab (RTX) has been used since 2006 to treat frequently relapsing NS. In adults, data about the efficacy of RTX for MCD are limited. We report our experience on the use of RTX in adult biopsy-proven MCD. Our series includes 6 adult patients (2 males and 4 females), age 45–73 years, treated with RTX (4 weekly doses of 375 mg/m²). Proteinuria decreased from 11,2 (23–4.8) g/24 hours to 0.6 (0–2) g/24 hours after 6 months, and to 0.4 (0–1, 4) g/24 h in the 4 pts with the longer follow-up. Creatinine decreased from 1.95 (0.5–5) mg/dl to 0.88 (0.6–1.3) mg/l. Five patients achieved a complete renal remission, while in 1 pt proteinuria decreased by 75%. RTX successfully depleted CD19 lymphocytes in 100% of pts for at least 6 months. No clinically relevant adverse events have been observed. This case series shows a remarkable efficacy of RTX in treatment of MCD. RTX can be an attractive alternative both in recurrent forms and in induction-therapy of MCD. RTX may be preferentially used in patients at a high risk of development of the adverse effects of corticosteroids and should be considered as an alternative option in patients with recurrent NS. Additional data are needed to inform clinical practice on how best to use RTX in this patient population, so that definitive randomized trials can be planned.

The Evolving Role of Rituximab in Adult Minimal Change Glomerulopathy

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Two-Year Follow-up Study of Membranous Nephropathy Treated With Tacrolimus and Corticosteroids Versus Cyclical Corticosteroids and Cyclophosphamide

Introduction

Both cCTX/GCs and CNIs are recommended as first-line agents in the management of PMN. The present study is an extended report of patients randomized to receive TAC/GCs or cCTX/GCs at 2 years post randomization.

Methods

Seventy patients enrolled in the clinical trial Tacrolimus Combined With Corticosteroids Versus Modified Ponticelli Regimen in Treatment of Idiopathic Membranous Nephropathy: Randomized Control Trial were followed quarterly between 12 and 24 months. At the end of 24 months, 3 patients were lost to follow-up.

Results

At 18 months, 66% and 89% (P = 0.04) were in remission in TAC/GCs and cCTX/GCs groups, respectively. At 18 and 24 months, 60% and 86% (P = 0.03) of cases were in remission in the TAC/GCs and cCTX/GCs groups, respectively. At 18 months, 57% and 83% (P = 0.03) of the patients in TAC/GCs and cCTX/GCs groups were in remission without need of any additional immunosuppression (persistent remission) and, at 24 months, 43% and 80% (P = 0.002) were in persistent remission in TAC/GCs and cCTX/GCs groups, respectively. Relapse rate after any remission was 40% and 6.7% in TAC/GCs and cCTX/GCs groups, respectively (P = 0.007). There was an association of aPLA2R titers with remission or resistance (P = 0.006) in relapsing PMN. The significant decrease in eGFR after 12 months of TAC/GCs therapy normalized at 18 and 24 months.

Discussion

At 2 years after randomization, relapse rates are higher for TAC/GCs compared with cCTX/GCs in PMN patients. Thus, cCTX/GCs are better than TAC/GCs in the longer term in PMN patients.

Calpain-Mediated Cleavage of Calcineurin in Puromycin Aminonucleoside-Induced Podocyte Injury

The calcineurin inhibitors cyclosporine A (CsA) and tacrolimus are widely used in the treatment of proteinuria diseases. As the direct target of these drugs, calcineurin has previously been demonstrated to play a role in proteinuria diseases. However, aside from its immune-related effects, the local status of calcineurin in renal inherent cells has not been fully explored in the settings of proteinuria disease and podocyte injury. In this study, calcineurin activity and protein expression in the well-known puromycin aminonucleoside (PAN)-induced podocyte injury model were examined. Interestingly, we found that calcineurin activity was abnormally increased in PAN-treated podocytes, whereas the expression of the full-length 60-kDa calcineurin protein was decreased. This result suggests that there may be another activated form of calcineurin that is independent of the full-length phosphatase. To investigate whether calpain is involved in regulating calcineurin, we exposed PAN-treated podocytes to both pharmacological inhibitors of calpain and specific siRNAs against calpain. Calpain blockade reduced the enhanced calcineurin activity and restored the down-regulated expression of 60-kDa calcineurin. In addition, purified calpain protein was incubated with podocyte extracts, and a 45-kDa fragment of calcineurin was identified; this finding was confirmed in PAN-induced podocyte injury and calpain inhibition experiments. We conclude that calcineurin activity is abnormally increased during PAN-induced podocyte injury, whereas the expression of the full-length 60-kDa calcineurin protein is down-regulated due to over-activated calpain that cleaves calcineurin to form a 45-kDa fragment.