Do we really need cyclophosphamide for lupus nephritis?

A 14-year-old patient presents with hematuria and proteinuria. Clinical evaluation reveals a positive anti-nuclear antibody titer, positive anti-double stranded DNA antibody and hypocomplementemia. Systemic lupus erythematosus (SLE) is diagnosed based on the 2019 EULAR/ACR (European League Against Rheumatism/American College of Rheumatology) classification criteria (Aringer et al. Arthritis Rheumatol 71:1400-1412, 2019). A kidney biopsy is performed that confirms the presence of immune complex glomerulonephritis, ISN-RPS (International Society of Nephrology/Renal Pathology Society) class IV (Bajema et al. Kidney Int 93:789-796, 2018). According to the latest clinical practice guidelines (Rovin et al. Kidney Int 100:753-779, 2021; Fanouriakis et al. Ann Rheum Dis 83:15-29, 2023), there are alternatives to treating this patient with cyclophosphamide. But what if this patient also presented with oliguria and volume overload requiring intensive care and dialysis? What if this patient also presented with altered mental status and seizures, and was diagnosed with neuropsychiatric lupus? What if this patient was also diagnosed with a pulmonary hemorrhage and respiratory failure? The clinical practice guidelines do not address these scenarios that are not uncommon in patients with SLE. Moreover, in some countries worldwide, patients do not have the privilege of access to biologics or more expensive alternatives. The purpose of this review is to evaluate the contemporary options for initial treatment of nephritis in patients with SLE.

Renal Response Outcomes of the EuroLupus and National Institutes of Health Cyclophosphamide Dosing Regimens in Childhood-Onset Proliferative Lupus Nephritis.

OBJECTIVE: We compared clinical characteristics and renal response in patients with childhood-onset proliferative lupus nephritis (LN) treated with the EuroLupus versus National Institutes of Health (NIH) cyclophosphamide (CYC) regimen. METHODS: A retrospective cohort study was conducted at 11 pediatric centers in North America that reported using both CYC regimens. Data were extracted from the electronic medical record at baseline and 3, 6, and 12 months after treatment initiation with CYC. To evaluate the adjusted association between CYC regimen (EuroLupus vs NIH) and renal response over time, generalized estimating equations with a logit link were used. An interaction between time and CYC regimen was included, and a contrast between CYC regimens at 12 months was used to evaluate the primary outcome. RESULTS: One hundred forty-five patients (58 EuroLupus, 87 NIH) were included. EuroLupus patients were on average older at the start of current CYC therapy, had longer disease duration, and more commonly had relapsed or refractory LN compared with the NIH group. After multivariable adjustment, there was no significant association between CYC regimen and achieving complete renal response at 12 months (odds ratio [OR] of response for the EuroLupus regimen, reference NIH regimen: 0.76; 95% confidence interval [CI] 0.29-1.98). There was also no significant association between CYC regimen and achieving at least a partial renal response at 12 months (OR 1.35, 95% CI 0.57-3.19). CONCLUSION: Our study failed to demonstrate a benefit of the NIH regimen over the EuroLupus CYC regimen in childhood-onset proliferative LN. However, future prospective outcome studies are needed.

Expansion of extrafollicular B and T cell subsets in childhood-onset systemic lupus erythematosus.

Introduction: Most childhood-onset SLE patients (cSLE) develop lupus nephritis (cLN), but only a small proportion achieve complete response to current therapies. The prognosis of children with LN and end-stage renal disease is particularly dire. Mortality rates within the first five years of renal replacement therapy may reach 22%. Thus, there is urgent need to decipher and target immune mechanisms that drive cLN. Despite the clear role of autoantibody production in SLE, targeted B cell therapies such as rituximab (anti-CD20) and belimumab (anti-BAFF) have shown only modest efficacy in cLN. While many studies have linked dysregulation of germinal center formation to SLE pathogenesis, other work supports a role for extrafollicular B cell activation in generation of pathogenic antibody secreting cells. However, whether extrafollicular B cell subsets and their T cell collaborators play a role in specific organ involvement in cLN and/or track with disease activity remains unknown. Methods: We analyzed high-dimensional mass cytometry and gene expression data from 24 treatment naïve cSLE patients at the time of diagnosis and longitudinally, applying novel computational tools to identify abnormalities associated with clinical manifestations (cLN) and disease activity (SLEDAI). Results: cSLE patients have an extrafollicular B cell expansion signature, with increased frequency of i) DN2, ii) Bnd2, iii) plasmablasts, and iv) peripheral T helper cells. Most importantly, we discovered that this extrafollicular signature correlates with disease activity in cLN, supporting extrafollicular T/B interactions as a mechanism underlying pediatric renal pathogenesis. Discussion: This study integrates established and emerging themes of extrafollicular B cell involvement in SLE by providing evidence for extrafollicular B and peripheral T helper cell expansion, along with elevated type 1 IFN activation, in a homogeneous cohort of treatment-naïve cSLE patients, a point at which they should display the most extreme state of their immune dysregulation.

Cognitive dysfunction in pediatric systemic lupus erythematosus: current knowledge and future directions.

Cognitive dysfunction (CD) is a neurologic complication of pediatric systemic lupus erythematosus (SLE) that remains poorly understood and understudied, despite the potential negative effects of CD on long-term socioeconomic status and quality of life. Data regarding the prevalence and risk factors for CD in pediatric SLE as well as the optimal screening, treatment, and long-term outcomes for CD are lacking. In this review, we present current knowledge on CD in pediatric SLE with a focus on the application to clinical practice. We discuss the challenges in diagnosis, clinical screening methods, potential impacts, and interventions for this complication. Finally, we discuss the remaining gaps in our knowledge of CD in pediatric SLE, and avenues for future research efforts.

Acute kidney injury requiring kidney replacement therapy in childhood lupus nephritis: a cohort study of the Pediatric Nephrology Research Consortium and Childhood Arthritis and Rheumatology Research Alliance.

BACKGROUND: Acute kidney injury (AKI) is common in lupus nephritis (LN) and a risk factor for development of chronic kidney disease. In adults with LN, AKI severity correlates with the incidence of kidney failure and patient survival. Data on AKI outcomes in children with LN, particularly those requiring kidney replacement therapy (KRT), are limited. METHODS: A multicenter, retrospective cohort study was performed in children diagnosed between 2010 and 2019 with LN and AKI stage 3 treated with dialysis (AKI stage 3D). Descriptive statistics were used to characterize demographics, clinical data, and kidney biopsy findings; treatment data for LN were not included. Logistic regression was used to examine the association of these variables with kidney failure. RESULTS: Fifty-nine patients (mean age 14.3 years, 84.7% female) were identified. The most common KRT indications were fluid overload (86.4%) and elevated blood urea nitrogen/creatinine (74.6%). Mean follow-up duration was 3.9 ± 2.9 years. AKI recovery without progression to kidney failure occurred in 37.3% of patients. AKI recovery with later progression to kidney failure occurred in 25.4% of patients, and there was no kidney recovery from AKI in 35.6% of patients. Older age, severe (> 50%) tubular atrophy and interstitial fibrosis, and National Institutes of Health (NIH) chronicity index score > 4 on kidney biopsy were associated with kidney failure. CONCLUSIONS: Children with LN and AKI stage 3D have a high long-term risk of kidney failure. Severe tubular atrophy and interstitial fibrosis at the time of AKI, but not AKI duration, are predictive of kidney disease progression. A higher resolution version of the Graphical abstract is available as Supplementary information.

The pediatric glucocorticoid toxicity index.

OBJECTIVES: To develop a Pediatric glucocorticoid toxicity index (pGTI), a standardized, weighted clinical outcome assessment that measures change in glucocorticoid (GC) toxicity over time. METHODS: Fourteen physician experts from 7 subspecialties participated. The physician experts represented multiple subspecialties in which GCs play a major role in the treatment of inflammatory disease: nephrology, rheumatology, oncology, endocrinology, genetics, psychiatry, and maternal-fetal medicine. Nine investigators were from Canada, Europe, or New Zealand, and 5 were from the United States. Group consensus methods and multi-criteria decision analysis were used. The pGTI is an aggregate assessment of GC toxicities that are common, important, and dynamic. These toxicities are organized into health domains graded as minor, moderate, or major and are weighted according to severity. The relative weights were derived by group consensus and multi-criteria decision analysis using the 1000MindsTM software platform. Two quantitative scores comprise the overall toxicity profile derived from pGTI data: (1) the Cumulative Worsening Score; and (2) the Aggregate Improvement Score. The pGTI also includes a qualitative, unweighted record of GC side-effects known as the Damage Checklist, which documents less common toxicities that, although potentially severe, are unlikely to change with varying GC dosing. RESULTS: One hundred and seven (107) toxicity items were included in the pGTI and thirty-two (32) in the Damage Checklist. To assess the degree to which the pGTI corresponds to expert clinical judgement, the investigators ranked 15 cases by clinical judgement from highest to lowest GC toxicity. Expert rankings were then compared to case ranking by the pGTI, yielding excellent agreement (weighted kappa 0.86). The pGTI was migrated to a digital environment following its development and initial validation. The digital platform is designed to ensure ease-of-use in the clinic, rigor in application, and accuracy of scoring. Clinic staff enter vital signs, laboratory results, and medication changes relevant to pGTI scoring. Clinicians record findings for GC myopathy, skin toxicity, mood dysfunction, and infection. The pGTI algorithms then apply the weights to these raw data and calculate scores. Embedded logic accounts for the impact of age- and sex-related reference ranges on several health domains: blood pressure, lipid metabolism, and bone mineral density. Other algorithms account for anticipated changes in the height Z-scores used in the growth domain, thereby addressing a concern unique to GC toxicity in children. The Damage Checklist ensures comprehensive measurement of GC toxicity but does not contribute to pGTI scoring, because the scored domains emphasize manifestations of GC toxicity that are likely to change over the course of a trial. CONCLUSIONS: We describe the development and initial evaluation of a weighted, composite toxicity index for the assessment of morbidity related to GC use in children and adolescents. Developing the pGTI digital platform was essential for performing the nuanced calculations necessary to ensure rigor, accuracy, and ease-of-use in both clinic and research settings.

Quantification of N, N' N"-triethylenethiophosphoramide, N, N"-triethylenephosphoramide, cyclophosphamide, and 4-hydroxy-cyclophosphamide in microvolume human plasma to support neonatal and pediatric drug studies.

N, N' N"-triethylenethiophosphoramide (thiotepa) and cyclophosphamide (CP) are alkylating agents used for a variety of malignant and non-malignant disorders. Both drugs are metabolized by cytochrome P450 enzymes to form active metabolites. To support pharmacokinetic studies of thiotepa and CP in children, we sought to develop assays to determine parent drug and metabolite concentration in small volume plasma samples. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for assay development. CP metabolite 4-hydroxycyclophosphamide (4OHCP) was converted to the more stable semicarbazone derivative (4OHCP-SCZ) for quantitation. Samples (10 µL) were extracted by solid-phase extraction and injected onto the LC-MS/MS system equipped with a pentafluorophenyl reverse phase column (2.1 × 50 mm, 2.7 µm). Electrospray ionization in positive mode was used for detection. Multiple reaction monitoring of the precursor-to-product ion transitions m/z 190→147 for thiotepa, 174→131 for tepa, 261→233 for CP, and 334→221 for 4OHCP-SCZ was selected for quantification. The ion transitions m/z 202→155 for thiotepa-d12, 186→139 for tepa-d12, 267→237 for CP-d4, and 340→114 for 4OHCP-d4-SCZ were selected for the internal standard (IS) corresponding to each analyte. The less abundant IS ions from 37Cl were used for CP-d4 and 4OHCP-d4-SCZ to overcome the cross-talk interference from the analytes. Under optimized conditions, retention times were 0.67 min for tepa and its IS, 2.50 min for thiotepa and its IS, 2.52 min for 4OHCP-SCZ and its IS, and 2.86 min for CP and its IS. Total run time was 5 min per sample. The calibration ranges were 2.5-2,000ng/mL for thiotepa and tepa, 20-10,000ng/mL for CP and 20-5,000 ng/mL for 4OHCP; Dilution integrity for samples above the calibration range was validated with 10-fold dilution for thiotepa/tepa and 20-fold dilution for CP/4OHCP. Recoveries ranged from 86.3-93.4% for thiotepa, 86.3-89.0% for tepa, 90.2-107% for CP, and 99.3-115% for 4OHCP-SCZ. The IS normalized matrix effect was within (100±7) % for all 4 analytes. Plasma samples at room temperature were stable for at least 60 hours for thiotepa, 6 days for tepa, and 24 hours for CP and 4OHCP-SCZ. Plasma samples for thiotepa/tepa were stable after 4 freeze-thaw cycles, and for CP/4OHCP-SCZ were stable after 3 freeze-thaw cycles. The assays were validated and applied to clinical studies requiring small sample volumes.

Use of EuroLupus Cyclophosphamide Dosing for the Treatment of Lupus Nephritis in Childhood-onset Systemic Lupus Erythematosus in North America.

OBJECTIVE: Childhood-onset systemic lupus erythematosus (cSLE) has higher rates of lupus nephritis (LN) than adult-onset SLE, often requiring intensive immunosuppression. This study examined North American practices and preferences for the low-dose EuroLupus cyclophosphamide (CYC) protocol, as compared to the high-dose National Institutes of Health (NIH) CYC protocol, to treat LN in cSLE. METHODS: A 35-item Web-based survey was distributed to Childhood Arthritis and Rheumatology Research Alliance (CARRA) and Pediatric Nephrology Research Consortium (PNRC) providers. The survey assessed participant demographics, CYC prescribing practices, perceptions of EuroLupus protocol, and LN vignette treatment decisions; 1 vignette was taken from a 2009 CARRA survey and responses were compared. Multivariable logistic regression analyzed provider factors associated with use of low- vs high-dose CYC. RESULTS: Responses were provided by 185/421 (44%) pediatric rheumatologists (CARRA) and 40/354 (11%) pediatric nephrologists (PNRC). Among respondents who prescribed CYC for pediatric LN over the past year (n = 135), half reported using EuroLupus. When presented with the same vignette about an adolescent with class IV LN, 32% of pediatric rheumatologists chose EuroLupus dosing in 2020, vs 6% in 2009. Provider factors associated with choosing the low-dose regimen were familiarity with the protocol (OR 4.2, P = 0.006) and greater perceived benefit (OR 1.6, P < 0.0001). Pediatric nephrologists had similar responses to the pediatric rheumatology providers. Overall, 78% of respondents perceived EuroLupus protocol efficacy to be equivalent to the high-dose protocol in cSLE LN. CONCLUSION: Pediatric specialists are currently more likely to use low-dose CYC to treat cSLE LN than they were a decade ago. Nevertheless, familiarity with EuroLupus dosing remains low.

Phase IIa Global Study Evaluating Rituximab for the Treatment of Pediatric Patients With Granulomatosis With Polyangiitis or Microscopic Polyangiitis.

OBJECTIVE: To assess the safety, tolerability, pharmacokinetics, and efficacy of rituximab (RTX) in pediatric patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). METHODS: The Pediatric Polyangiitis Rituximab Study was a phase IIa, international, open-label, single-arm study. During the initial 6-month remission-induction phase, patients received intravenous infusions of RTX (375 mg/m2 body surface area) and glucocorticoids once per week for 4 weeks. During the follow-up period, patients could receive further treatment, including RTX, for GPA or MPA. The safety, pharmacokinetics, pharmacodynamics, and exploratory efficacy outcomes with RTX were evaluated. RESULTS: Twenty-five pediatric patients with new-onset or relapsing disease were enrolled at 11 centers (19 with GPA [76%] and 6 with MPA [24%]). The median age was 14 years (range 6-17 years). All patients completed the remission-induction phase. During the overall study period (≤4.5 years), patients received between 4 and 28 infusions of RTX. All patients experienced ≥1 adverse event (AE), mostly grade 1 or grade 2 primarily infusion-related reactions. Seven patients experienced 10 serious AEs, and 17 patients experienced 31 infection-related AEs. No deaths were reported. RTX clearance correlated with body surface area. The body surface area-adjusted RTX dosing regimen resulted in similar exposure in both pediatric and adult patients with GPA or MPA. Remission, according to the Pediatric Vasculitis Activity Score, was achieved in 56%, 92%, and 100% of patients by months 6, 12, and 18, respectively. CONCLUSION: In pediatric patients with GPA or MPA, RTX is well tolerated and effective, with an overall safety profile comparable to that observed in adult patients with GPA or MPA who receive treatment with RTX. RTX is associated with a positive risk/benefit profile in pediatric patients with active GPA or MPA.

Population pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide metabolite in patients with autoimmune glomerulonephritis.

OBJECTIVES: To develop a simultaneous population pharmacokinetic model of cyclophosphamide (CY) and 4-hydroxycyclophosphamide (4-OH) in patients with glomerulonephritis. METHODS: In total, 23 patients participated in a pharmacokinetic evaluation using dense plasma sampling. A population pharmacokinetic model was developed in Monolix Suite 2020R1 that simultaneously describes the kinetics of CY and 4-OH. Several structural and residual error models were evaluated and patient variables were tested as potential covariates. The final model was selected based on visual predictive check and bootstrap. Simulations of plasma concentrations for various doses were conducted. KEY FINDINGS: A model including two compartments for CY and one for 4-OH was found to best describe the data. A proportional error model for both compounds was chosen. The following estimates were found for the main CY pharmacokinetic parameters: total clearance, 13.3 l/h with inter-individual variability (IIV) 32%, and central volume of distribution, 59.8 l with IIV 12%. The metabolite elimination rate constant was 4.3 h-1 with IIV 36% and the proportion of metabolism 64%. Sex was a significant covariate on the central volume of CY, with females exhibiting 25% lower value than males. CONCLUSIONS: A population pharmacokinetic model was developed for CY and 4-OH in patients with autoimmune glomerulonephritis. Simulations using various dose regimens allow for informed dosing before the initiation of therapy.

Pilot study comparing the childhood arthritis and rheumatology research alliance consensus treatment plans for induction therapy of juvenile proliferative lupus nephritis.

BACKGROUND: To reduce treatment variability and facilitate comparative effectiveness studies, the Childhood Arthritis and Rheumatology Research Alliance (CARRA) published consensus treatment plans (CTPs) including one for juvenile proliferative lupus nephritis (LN). Induction immunosuppression CTPs outline treatment with either monthly intravenous (IV) cyclophosphamide (CYC) or mycophenolate mofetil (MMF) in conjunction with one of three corticosteroid (steroid) CTPs: primarily oral, primarily IV or mixed oral/IV. The acceptability and in-practice use of these CTPs are unknown. Therefore, the primary aims of the pilot study were to demonstrate feasibility of adhering to the LN CTPs and delineate barriers to implementation in clinical care in the US. Further, we aimed to explore the safety and effectiveness of the treatments for induction therapy. METHODS: Forty-one patients were enrolled from 10 CARRA sites. Patients had new-onset biopsy proven ISN/RPS class III or IV proliferative LN, were starting induction therapy with MMF or IV CYC and high-dose steroids and were followed for up to 24 months. Routine clinical data were collected at each visit. Provider reasons for CTP selection were assessed at baseline. Adherence to the CTPs was evaluated by provider survey and medication logs. Complete and partial renal responses were reported at 6 months. RESULTS: The majority of patients were female (83%) with a mean age of 14.7 years, SD 2.8. CYC was used more commonly than MMF for patients with ISN/RPS class IV LN (vs. class III), those who had hematuria, and those with adherence concerns. Overall adherence to the immunosuppression induction CTPs was acceptable with a majority of patients receiving the target MMF (86%) or CYC (63%) dose. However, adherence to the steroid CTPs was poor (37%) with large variability in dosing. Renal response endpoints were exploratory and did not show a significant difference between CYC and MMF. CONCLUSIONS: Overall, the immunosuppression CTPs were followed as intended in the majority of patients however, adherence to the steroid CTPs was poor indicating revision is necessary. In addition, our pilot study revealed several sources of treatment selection bias that will need to be addressed in for future comparative effectiveness research.

Approach to Membranous Lupus Nephritis: A Survey of Pediatric Nephrologists and Pediatric Rheumatologists.

OBJECTIVE: To describe treatment practices for childhood pure membranous lupus nephritis (MLN). METHODS: Survey study of Childhood Arthritis and Rheumatology Research Alliance and American Society of Pediatric Nephrology members. RESULTS: There were 117 respondents who completed the survey (60 pediatric nephrologists, 57 pediatric rheumatologists). Steroids and nonsteroid immunosuppression (NSI) were routinely used by the majority for MLN. Mycophenolate mofetil was the favored initial NSI. Nephrologists used steroids (60% vs 93%) and NSI (53% vs 87%) less often than did rheumatologists for MLN without nephrotic syndrome (NS). CONCLUSION: Pediatric rheumatologists and nephrologists both recommend steroids and NSI for children with MLN, with or without NS.