Cattran, Daniel C.

Key Points In phospholipase A2 receptor-membranous nephropathy, clinical variables and antibody levels over 3 or 6 months of treatment were predictors of remission at 1 year. Prediction models at 3 and 6 months had similar performance predicting remission, with the 3-month model allowing for earlier assessment of response. The 3-month and 6-month prediction models could be applied in those treated with supportive therapy, rituximab, calcineurin inhibitors, or cyclophosphamide. Background In patients with antiphospholipase A2 receptor antibody–associated membranous nephropathy, there is currently no accepted method to predict an individual's probability of remission after treatment with immunosuppression or supportive therapy using changes in antibody levels and clinical variables during the first 3–6 months of therapy. Methods Using a cohort of 187 patients from the Glomérulopathie extramembraneuse rituximab, Membranous Nephropathy Trial of Rituximab, and Sequential Treatment with Tacrolimus and Rituximab Versus Alternating Corticosteroids and Cyclophosphamide in primary Membranous Nephropathy clinical trials with antibody levels at baseline ≥14 RU/ml, we derived logistic regression models to predict proteinuria remission at 12 months that can be used at baseline or after 3 or 6 months of treatment. Treatment exposures in the trials included supportive therapy, rituximab, calcineurin inhibitors, and cyclophosphamide. Predictors in the models included male sex and baseline and changes in serum albumin, proteinuria, and antibody levels, with or without changes in eGFR. Results Proteinuria remission at 12 months was achieved in 107 patients. Compared with the model at baseline, the 3-month and 6-month models had better model fit with lower Akaike information criterion (186/158 versus 225) and higher R 2 (52.7%/62.4% versus 25.8%), better discrimination with higher C-statistic (0.87 and 0.91 versus 0.75, P < 0.001), and better calibration with lower integrated calibration index (0.89%/2.22% versus 2.51%). The 3-month and 6-month models had no consistent difference in prediction performance, and decision curve analysis demonstrated similar net benefit for treatment decisions based on either model up to a threshold probability of 31%. Prediction performance was similar after internal validation using optimism correction. Prediction performance was maintained within subgroups of different treatment regimens, including supportive therapy, rituximab, calcineurin inhibitors, and cyclophosphamide. Conclusions Either the 3-month or 6-month models can be used in patients with antiphospholipase A2 receptor antibody associated membranous nephropathy after 3 or 6 months of treatment with a variety of immunosuppression or supportive therapy to predict remission status at 12 months.

ABSTRACT Background and hypothesis The MENTOR trial (MEmbranous Nephropathy Trial Of Rituximab) showed that rituximab was noninferior to cyclosporine in inducing complete or partial remission of proteinuria and was superior in maintaining proteinuria remission. However, the cost of rituximab may prohibit first-line use for some patients and health-care payers. Methods A Markov model was used to determine the incremental cost-effectiveness ratio (ICER) of rituximab compared with cyclosporine for the treatment membranous nephropathy from the perspective of a health-care payer with a lifetime time horizon. The model was informed by data from the MENTOR trial where possible; additional parameters including cost and utility inputs were obtained from the literature. Sensitivity analyses were performed to evaluate the impact of reduced-cost biosimilar rituximab. Results Rituximab for the treatment of membranous nephropathy was cost effective (assuming a willingness-to-pay threshold of $50 000 per quality-adjusted life year (QALY) gained; in $US 2021) compared with cyclosporine, with an ICER of $8373/QALY over a lifetime time horizon. The incremental cost of rituximab therapy was $28 007 with an additional 3.34 QALYs compared with cyclosporine. Lower cost of rituximab biosimilars resulted in a more favorable ICER, and in some cases resulted in rituximab being dominant (lower cost and great benefit) compared to cyclosporine. Conclusions Despite the greater cost of rituximab, it may be a cost-effective option for the treatment of membranous nephropathy when compared with cyclosporine. The cost-effectiveness of rituximab is further improved with the use of less expensive biosimilars.

Background and objectives C3 glomerulopathy and idiopathic Ig-associated membranoproliferative GN are kidney diseases characterized by abnormal glomerular complement C3 deposition. These conditions are heterogeneous in outcome, but approximately 50% of patients develop kidney failure within 10 years. Design, setting, participants, & measurements To improve identification of patients with poor prognosis, we performed a detailed analysis of percutaneous kidney biopsies in a large cohort of patients. Using a validated histologic scoring system, we analyzed 156 native diagnostic kidney biopsies from a retrospective cohort of 123 patients with C3 glomerulopathy and 33 patients with Ig-associated membranoproliferative GN. We used linear regression, survival analysis, and Cox proportional hazards models to assess the relationship between histologic and clinical parameters with outcome. Results Frequent biopsy features were mesangial expansion and hypercellularity, glomerular basement membrane double contours, and endocapillary hypercellularity. Multivariable analysis showed negative associations between eGFR and crescents, interstitial inflammation, and interstitial fibrosis/tubular atrophy. Proteinuria positively associated with endocapillary hypercellularity and glomerular basement membrane double contours. Analysis of second native biopsies did not demonstrate associations between immunosuppression treatment and improvement in histology. Using a composite outcome, risk of progression to kidney failure associated with eGFR and proteinuria at the time of biopsy, cellular/fibrocellular crescents, segmental sclerosis, and interstitial fibrosis/tubular atrophy scores. Conclusions Our detailed assessment of kidney biopsy data indicated that cellular/fibrocellular crescents and interstitial fibrosis/tubular atrophy scores were significant determinants of deterioration in kidney function.

Abstract Background Understanding the relationship between clinical and patient-reported outcomes (PROs) will help support clinical care and future clinical trial design of novel therapies for focal segmental glomerulosclerosis (FSGS). Methods FSGS patients ≥8 years of age enrolled in the Nephrotic Syndrome Study Network completed Patient-Reported Outcomes Measurement Information System PRO measures of health-related quality of life (HRQoL) (children: global health, mobility, fatigue, pain interference, depression, anxiety, stress and peer relationships; adults: physical functioning, fatigue, pain interference, sleep impairment, mental health, depression, anxiety and social satisfaction) at baseline and during longitudinal follow-up for a maximum of 5 years. Linear mixed-effects models were used to determine which demographic, clinical and laboratory features were associated with PROs for each of the eight children and eight adults studied. Results There were 45 children and 114 adult FSGS patients enrolled that had at least one PRO assessment and 519 patient visits. Multivariable analyses among children found that edema was associated with global health (−7.6 points, P = 0.02) and mobility (−4.2, P = 0.02), the number of reported symptoms was associated with worse depression (−2.7 per symptom, P = 0.009) and anxiety (−2.3, P = 0.02) and the number of emergency room (ER) visits in the prior 6 months was associated with worse mobility (−2.8 per visit, P &lt; 0.001) and fatigue (−2.4, P = 0.03). Multivariable analyses among adults found the number of reported symptoms was associated with worse function in all eight PROMIS measures and the number of ER visits was associated with worse fatigue, pain interference, sleep impairment, depression, anxiety and social satisfaction. Laboratory markers of disease severity (i.e. proteinuria, estimated glomerular filtration rate and serum albumin) did not predict PRO in multivariable analyses, with the single exception of complete remission and better pain interference scores among children (+9.3, P = 0.03). Conclusions PROs provide important information about HRQoL for persons with FSGS that is not captured solely by the examination of laboratory-based markers of disease. However, it is critical that instruments capture the patient experience and FSGS clinical trials may benefit from a disease-specific instrument more sensitive to within-patient changes.