The Time Has Come: The Case for Initiating Pilot Clinical Trials of Pig Kidney Xenotransplantation.

In vitro studies indicate that kidney transplantation from gene-edited pigs in which expression of all three of the known glycan xenoantigens has been deleted may be more challenging in nonhuman primates (NHPs) than it will be in human recipients. Furthermore, pig-to-human xenotransplantation offers several other advantages - (i) the patient can communicate with the surgical team; (ii) recipient microbiological monitoring and environment will be clinical-grade; and (iii) sophisticated graft monitoring and imaging techniques, (v) therapeutic interventions, e.g., dialysis, plasmapheresis, and (v) intensive care can be deployed that are not easily available in NHP laboratory models. We suggest, therefore, that progress to develop safe, informative human clinical trials will be accelerated if pilot clinical cases are initiated. The selection of patients for kidney xenotransplantation can include those who are at high risk of dying imminently, e.g., those experiencing increasing vascular access challenges with no realistic alternative therapy available, and those who have been accepted onto the waitlist for an allograft, but who are unlikely ever to receive one. Patients with an increased risk of dying include those with (i) age >60 years, (ii) blood groups O or B, and (iii) diabetic nephropathy. UNOS data indicate that an average of 25 patients on the kidney waitlist in the USA die or are removed from the list every day (i.e., >9,000 each year). Given the improved xenograft survival observed in preclinical studies, we suggest that it is time to plan a small pilot clinical trial for healthy dialysis patients who understand the risks and potential benefits of kidney xenotransplantation.

Banff Human Organ Transplant Transcripts Correlate with Renal Allograft Pathology and Outcome: Importance of Capillaritis and Subpathologic Rejection.

BACKGROUND: To seek insights into the pathogenesis of chronic active antibody-mediated rejection (CAMR), we performed mRNA analysis and correlated transcripts with pathologic component scores and graft outcomes. METHODS: We utilized the NanoString nCounter platform and the Banff Human Organ Transplant gene panel to quantify transcripts on 326 archived renal allograft biopsy samples. This system allowed correlation of transcripts with Banff pathology scores from the same tissue block and correlation with long-term outcomes. RESULTS: The only pathology score that correlated with AMR pathways in CAMR was peritubular capillaritis (ptc). C4d, cg, g, v, i, t, or ci scores did not correlate. DSA-negative CAMR had lower AMR pathway scores than DSA-positive CAMR. Transcript analysis in non-CAMR biopsies yielded evidence of increased risk of later CAMR. Among 108 patients without histologic CAMR, 23 developed overt biopsy-documented CAMR within 5 years and as a group had higher AMR pathway scores (P=3.4 × 10-5). Random forest analysis correlated 3-year graft loss with elevated damage, innate immunity, and macrophage pathway scores in CAMR and TCMR. Graft failure in CAMR was associated with TCMR transcripts but not with AMR transcripts, and graft failure in TCMR was associated with AMR transcripts but not with TCMR transcripts. CONCLUSIONS: Peritubular capillary inflammation and DSA are the primary drivers of AMR transcript elevation. Transcripts revealed subpathological evidence of AMR, which often preceded histologic CAMR and subpathological evidence of TCMR that predicted graft loss in CAMR.

Temporal trends and impact of willingness to accept organs from donors with hepatitis C virus.

Direct-acting antivirals (DAA) transformed hepatitis C virus (HCV) treatment in 2014; however, their impact on transplant candidates' willingness to accept (CWTA) organs from HCV+ donors remains uncertain. We retrospectively studied Organ Procurement and Transplantation Network data from 2008 to 2019, investigating CWTA different organs from HCV+ donors over time, using segmented multivariable logistic regression, and how that influenced wait-time and deceased-donor transplantation (DDTx) probability, using multivariable logistic or linear regression. We found that DAA availability was associated with a marked increase in CWTA in all organs from HCV+ donors except intestine. By December 2020, 40% of kidney, 33% of kidney-pancreas, 42% of pancreas, over 50% of liver, heart, lung, heart-lung, and 9% of intestine candidates waitlisted were CWTA an organ from HCV+ donors. Compared with pre-DAA, yearly CWTA kidney from HCV+ donors increased post-DAA 1.78 1.811.83 -fold, kidney-pancreas 2 .52 2.78 3.07 -fold, pancreas 3.15 3.69 4.43 -fold, liver 1.53 1.541.56 -fold, heart 1 .92 2.02 .08 -fold, and lung 2.00 2.12 .20 -fold. CWTA kidney and liver from HCV+ donors significantly increased DDTx probability post-DAA (1.98 2.042.1 -fold and 1.24 1.291.33 -fold, respectively) and shortened kidney candidates' wait-time78 90101 days (Mean with 95% CI). CWTA organs from HCV+ donors rose significantly with DAA availability, benefitting kidney and liver candidates with increased DDTx rates and shortened kidney candidates' wait time. Further long-term outcomes investigation and standardized organ from HCV+ donors' education could improve both provider and patient acceptance and utilization.

Racial disparities in preemptive waitlisting and deceased donor kidney transplantation: Ethics and solutions.

Kidney transplantation prior to dialysis, known as "preemptive transplant," enables patients to live longer and avoid the substantial quality of life burdens due to chronic dialysis. Deceased donor kidneys are a public resource that ought to provide health benefits equitably. Unfortunately, White, better educated, and privately insured patients enjoy disproportionate access to preemptive transplantation using deceased donor kidneys. This problem has persisted for decades and is exacerbated by the first-come, first-served approach to kidney allocation for predialysis patients. In this Personal Viewpoint, we describe the diverse barriers to preemptive waitlisting and kidney transplant. The analysis focuses on healthcare system features that particularly disadvantage Black patients, such as the waitlisting eligibility criterion of a single glomerular filtration rate or creatinine clearance ≤20 ml/min, and neglect of wide variation in the rate of progression to end-stage kidney disease (ESKD) in allocating preemptive transplants. We propose initiatives to improve equity including: (1) standardization of waitlisting eligibility criteria related to kidney function; (2) aggressive education for clinicians about early transplant referral; (3) innovations in electronic medical record capabilities; and (4) rapid status 7 listing by centers. If those initiatives fail, the transplant field should consider eliminating preemptive waitlisting and transplantation with deceased donor kidneys.

Multicenter Study to Transplant Hepatitis C-Infected Kidneys (MYTHIC): An Open-Label Study of Combined Glecaprevir and Pibrentasvir to Treat Recipients of Transplanted Kidneys from Deceased Donors with Hepatitis C Virus Infection.

BACKGROUND: Single-center trials and retrospective case series have reported promising outcomes using kidneys from donors with hepatitis C virus (HCV) infection. However, multicenter trials are needed to determine if those findings are generalizable. METHODS: We conducted a prospective trial at seven centers to transplant 30 kidneys from deceased donors with HCV viremia into HCV-uninfected recipients, followed by 8 weeks of once-daily coformulated glecaprevir and pibrentasvir, targeted to start 3 days posttransplant. Key outcomes included sustained virologic response (undetectable HCV RNA 12 weeks after completing treatment with glecaprevir and pibrentasvir), adverse events, and allograft function. RESULTS: We screened 76 patients and enrolled 63 patients, of whom 30 underwent kidney transplantation from an HCV-viremic deceased donor (median kidney donor profile index, 53%) in May 2019 through October 2019. The median time between consent and transplantation of a kidney from an HCV-viremic donor was 6.3 weeks. All 30 recipients achieved a sustained virologic response. One recipient died of complications of sepsis 4 months after achieving a sustained virologic response. No severe adverse events in any patient were deemed likely related to HCV infection or treatment with glecaprevir and pibrentasvir. Three recipients developed acute cellular rejection, which was borderline in one case. Three recipients developed polyomavirus (BK) viremia near or >10,000 copies/ml that resolved after reduction of immunosuppression. All recipients had good allograft function, with a median creatinine of 1.2 mg/dl and median eGFR of 57 ml/min per 1.73 m2 at 6 months. CONCLUSIONS: Our multicenter trial demonstrated safety and efficacy of transplantation of 30 HCV-viremic kidneys into HCV-negative recipients, followed by early initiation of an 8-week regimen of glecaprevir and pibrentasvir.

Preemptive Treatment With Elbasvir and Grazoprevir for Hepatitis C-Viremic Donor to Uninfected Recipient Kidney Transplantation.

INTRODUCTION: Long wait times for kidney transplants have prompted investigation into strategies to decrease the discarding of potentially viable organs. Recent reports suggest that kidneys from hepatitis C virus (HCV)-infected donors may be transplanted into HCV-naive donors followed by direct-acting antiviral therapy. METHODS: This was a pilot clinical trial to transplant kidneys from HCV-infected donors into HCV-naive recipients with preemptive use of elbasvir and grazoprevir for 12 weeks. The primary outcome was sustained virologic response 12 weeks after completion of therapy. Secondary outcomes were safety, quality of life, and early viral kinetics. RESULTS: A total of 33 patients were screened, and 8 underwent kidney transplantation from a HCV-viremic donors from August 2017 to March 2019. The median donor kidney donor profile index was 31% (range, 29%-65%), and patients who underwent transplantation waited a median of 6.5 months (range, 1-19 months). None had detectable HCV viremia beyond 2 weeks post-transplantation, and all achieved sustained virologic response 12 weeks after therapy (SVR12). There were no study-related severe adverse events. One patient experienced early graft loss due to venous thrombosis, whereas the remaining 7 patients had excellent allograft function at 6 months. CONCLUSION: Preemptive elbasvir and grazoprevir eliminated HCV infection in HCV-naive patients who received a kidney transplant from an HCV-infected donor.

From Theory to Reality: Establishing a Successful Kidney Genetics Clinic in the Outpatient Setting.

Background: Genetic testing in nephrology is increasingly described in the literature and several groups have suggested significant clinical benefit. However, studies to date have described experience from established genetic testing centers or from externally funded research programs. Methods: We established a de novo kidney genetics clinic within an academic adult general nephrology practice. Key features of this effort included a pipeline for internal referrals, flexible scheduling, close coordination between the nephrologist and a genetic counselor, and utilization of commercial panel-based testing. Over the first year, we examined the outcomes of genetic testing, the time to return of genetic testing, and out-of-pocket cost to patients. Results: Thirty patients were referred and 23 were evaluated over the course of five clinic sessions. Nineteen patients underwent genetic testing with new diagnoses in nine patients (47%), inconclusive results in three patients (16%), and clearance for kidney donation in two patients (11%). On average, return of genetic results occurred 55 days (range 9-174 days) from the day of sample submission and the average out-of-pocket cost to patients was $155 (range $0-$1623). Conclusions: We established a kidney genetics clinic, without a pre-existing genetics infrastructure or dedicated research funding, that identified a new diagnosis in approximately 50% of patients tested. This study provides a clinical practice model for successfully incorporating genetic testing into ambulatory nephrology care with minimal capital investment and limited financial effect on patients.

Process of selecting and educating HCV-uninfected kidney waiting-list candidates for HCV-infected kidney transplantation.

Long waiting times for kidney transplant (KT) and the high risk of mortality on dialysis have prompted investigation into strategies to utilize hepatitis C virus (HCV)-infected organs to decrease discard rates of potentially viable kidneys. Due the opioid epidemic, the number of HCV-infected donors has increased significantly. With the development of direct-acting antiviral therapies for HCV infection, now more than 95% of patients who received treatment are cured. Experimental trials have used direct-acting antiviral therapy to treat HCV infection in HCV-uninfected transplant recipients of kidneys from HCV-viremic donors. To date, HCV has been eradicated in all cases. Though these strategies will potentially increase the donor pool of available kidneys, shorten waitlist times, and ultimately decrease mortality in patients waiting for KT, identifying the ideal candidates and educating them about a protocol to utilize direct-acting antiviral therapy to cure HCV after it is transmitted is essential. We present our approach to patient selection and education for a clinical trial in transplantation of HCV viremic kidneys into uninfected recipients.