Ters, Mireille El

Abstract Background and Aims Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) has a poor renal prognosis and a high rate of recurrence after kidney transplantation, up to 90%, typically within the first-year post-transplant. Nearly 50% of patients lose their renal allograft within 3 years of recurrence. It has been suggested that pretreatment therapy (with B cell depleting or plasma-cell directed therapy) can help prevent recurrence or modulate the course of disease post-transplant. The aim of our study is to evaluate the effect of pretreatment therapy given within 6 months prior to kidney transplant on outcomes including PGNMID recurrence and all cause graft loss. Method Between 1996 and 2022, a total of 28 patients with biopsy-proven PGNMID as the cause of end stage kidney disease received a total of 31 kidney transplants. All patients had at least one year of follow-up data, for all but one patient this included surveillance kidney transplant biopsies completed at our center. Recurrence was defined histologically by immunofluorescence finding of monoclonal immunoglobulin deposits, independent of other histological or clinical parameters. The incidence of recurrence and all cause graft loss were analyzed by Kaplan-Meier plots. Results Median age of patients at transplant was 57 years, 87% were white, 65% were male, 74% received living donor transplant, 59% received thymoglobulin induction, 81% received maintenance with tacrolimus, mycophenolate, and prednisone. Median follow up time was 80 months. A total of 9 patients received pretreatment within 6 months of transplant, 8 received Rituximab and one received Daratumumab. The pretreatment group was generally younger at transplant (53 years vs 57 years) and had a shorter median follow up time (65 months vs 96.5 months), but neither were statistically significant. Overall recurrence rate was 78% for pretreatment and 91% for control, though difference in time to recurrence was not statistically significant (Fig. 1). The difference in all cause graft loss between groups was not statistically significant, however, none in the pretreatment group had graft loss by 60 months (Fig. 2). One patient who received daratumumab had no recurrence by 1 year post-transplant. Conclusion In kidney transplant recipients with PGNMID, pretreatment (primarily with rituximab) may be modulating the post-transplant course of disease. Further studies are needed to determine the extent of this effect and if plasma-cell directed vs B-cell directed therapy may be superior.

Abstract Background In the United States, rare disease (RD) is defined as a condition that affects fewer than 200,000 individuals. Collectively, RD affects an estimated 30 million Americans. A significant portion of RD has an underlying genetic cause; however, this may go undiagnosed. To better serve these patients, the Mayo Clinic Program for Rare and Undiagnosed Diseases (PRaUD) was created under the auspices of the Center for Individualized Medicine (CIM) aiming to integrate genomics into subspecialty practice including targeted genetic testing, research, and education. Methods Patients were identified by subspecialty healthcare providers from 11 clinical divisions/departments. Targeted multi-gene panels or custom exome/genome-based panels were utilized. To support the goals of PRaUD, a new clinical service model, the Genetic Testing and Counseling (GTAC) unit, was established to improve access and increase efficiency for genetic test facilitation. The GTAC unit includes genetic counselors, genetic counseling assistants, genetic nurses, and a medical geneticist. Patients receive abbreviated point-of-care genetic counseling and testing through a partnership with subspecialty providers. Results Implementation of PRaUD began in 2018 and GTAC unit launched in 2020 to support program expansion. Currently, 29 RD clinical indications are included in 11 specialty divisions/departments with over 142 referring providers. To date, 1,152 patients have been evaluated with an overall solve rate of 14.1% and as high as 66.7% depending on the phenotype. Noteworthy, 42.7% of the solved or likely solved patients underwent changes in medical management and outcome based on genetic test results. Conclusion Implementation of PRaUD and GTAC have enabled subspecialty practices advance expertise in RD where genetic counselors have not historically been embedded in practice. Democratizing access to genetic testing and counseling can broaden the reach of patients with RD and increase the diagnostic yield of such indications leading to better medical management as well as expanding research opportunities.

Background. Recent studies identified underlying genetic causes in a proportion of patients with various forms of kidney disease. In particular, genetic testing reclassified some focal segmental glomerulosclerosis (FSGS) cases into collagen type 4 (COL4)-related nephropathy. This knowledge has major implications for counseling prospective transplant recipients about recurrence risk and screening biologically related donors. We describe our experience incorporating genetic testing in our kidney transplant multidisciplinary practice. Methods. Patients’ DNA was analyzed using whole exome sequencing for a comprehensive kidney gene panel encompassing 344 genes associated with kidney diseases and candidate genes highly expressed in the kidney. Results were correlated with phenotype by a multidisciplinary committee of nephrologists, renal pathologists, geneticists, and genetic counselors. Between October 2018 and July 2020, 30 recipient and 5 donor candidates completed testing. Results. Among recipient candidates, 24 (80%) carried the diagnosis of FSGS, 2 (6.7%) tubulointerstitial nephritis, and 1 (3.3%) nephrolithiasis, and 3 (10%) had an unknown cause of kidney disease. The yield for pathogenic/likely pathogenic variants was 43.3%, with majority being COL4 variants (53.8%). Among those with FSGS diagnosis, the yield was 10 of 24 (41.6%), with 29% reclassified into a COL4-related nephropathy. Family history of kidney disease was the only clinical characteristic difference between recipients with positive and negative results (76.9 versus 29.4%; P = 0.025). One of 5 donors tested positive for a pathogenic/likely pathogenic variant and was excluded from donation. Conclusions. We conclude that thoughtful use of genetic testing can be valuable for kidney donor selection and transplant recipient management.

Significance Statement Treatment of proliferative GN with monoclonal Ig deposition (PGNMID), in which direct deposition of the monoclonal proteins damages the kidney, is not established. Daratumumab, a monoclonal anti-CD38 antibody, has shown effectiveness as multiple myeloma therapy. In an open-label, phase 2 study, the authors evaluated safety and efficacy of a 6-month course of intravenous daratumumab in 11 patients with PGNMID and one with C3 glomerulopathy with monoclonal gammopathy. Five episodes of serious adverse events (two of which were infection related) occurred. All ten patients with PGNMID who received at least one daratumumab dose experienced a significant reduction in proteinuria at 6 months, which was sustained in seven patients by 12 months. Overall, in this pilot study, daratumumab’s acceptable toxicity profile and significant improvement in proteinuria, while stabilizing kidney function, suggest further investigation is warranted. Background Treatment of proliferative GN with monoclonal Ig deposits (PGNMID) is not established. A monoclonal anti-CD38 antibody (daratumumab) is effective in treating multiple myeloma. Abnormal plasma cell clones may play a role in the pathogenesis of PGNMID. Methods We evaluated daratumumab’s safety and efficacy in an open-label, phase 2 trial in 11 adults with PGNMID and one with C3 glomerulopathy (C3G) with monoclonal gammopathy. Patients had an eGFR >20 ml/min per 1.73 m 2 and proteinuria >1 g/d. They received daratumumab intravenously (16 mg/kg) once weekly for 8 weeks, and then every other week for eight additional doses. Primary outcome was safety, defined as major infections, grade 3 or 4 anemia, leukopenia, or thrombocytopenia. Secondary outcomes were rate of complete remission (proteinuria <500 mg/d with <15% decline in baseline eGFR) or partial remission (>50% reduction in 24-hour proteinuria with <30% decline in eGFR) and proteinuria at 6 and 12 months. Results One patient with C3G had GN unrelated to the monoclonal gammopathy, and one with PGNMID did not complete the first infusion. Five serious adverse events occurred. During the 12 months of the trial, six of the ten patients with PGNMID who received at least one dose of daratumumab had a partial response, and four had a complete response (an overall response rate of 100%). Three patients experienced relapse, two of whom re-entered partial remission after resuming daratumumab therapy. Proteinuria declined significantly, from a median of 4346 mg/d to 1264 mg/d by 12 months. Conclusions Daratumumab demonstrated an acceptable safety profile and resulted in significant improvement in proteinuria while stabilizing kidney function in patients with PGNMID, suggesting the drug merits further investigation. Clinical Trial registry name and registration number: Daratumumab in Treatment of PGNMID and C3 GN, NCT03095118