Rilparencel (Renal Autologous Cell Therapy-REACT®) for Chronic Kidney Disease and Type 1 and Type 2 Diabetes: Phase 2 Trial Design Evaluating Bilateral Kidney Dosing and Redosing Triggers.

INTRODUCTION: Autologous cell-based therapies (CBT) to treat chronic kidney disease (CKD) with diabetes are novel and can potentially preserve renal function and decelerate disease progression. CBT dosing schedules are in early development and may benefit from individual bilateral organ dosing and kidney-dependent function to improve efficacy and durability. The objective of this open-label, phase 2 randomized controlled trial (RCT) is to evaluate participants' responses to rilparencel (Renal Autologous Cell Therapy-REACT®) following bilateral percutaneous kidney injections into the kidney cortex with a prescribed dosing schedule versus redosing based on biomarker triggers. METHODS: Eligible participants with type 1 or 2 diabetes and CKD, eGFR 20-50 mL/min/1.73 m2, urine albumin-to-creatinine ratio (UACR) 30-5,000 mg/g, hemoglobin >10 g/dL, and glycosylated hemoglobin <10% were enrolled. After a percutaneous kidney biopsy and bioprocessing ex vivo expansion of selected renal cells, participants were randomized 1:1 into two cohorts determined by the dosing scheme. Cohort 1 receives 2 cell injections, one in each kidney 3 months apart, and cohort 2 receives one injection and the second dose only if there is a sustained eGFR decline of ≥20 mL/min/1.73 m2 and/or UACR increase of ≥30% and ≥30 mg/g, confirmed by re-testing. CONCLUSION: The trial is fully enrolled with fifty-three participants. Cell injections and follow-up clinical visits are ongoing. This multicenter phase 2 RCT is designed to investigate the efficacy and safety of rilparencel with bilateral kidney dosing and compare two injection schedules with the potential of preserving or improving kidney function and delaying kidney disease progression among patients with stages 3a-4 CKD with diabetes.

Effects of Bardoxolone Methyl in Alport Syndrome.

BACKGROUND AND OBJECTIVES: Alport syndrome is an inherited disease characterized by progressive loss of kidney function. We aimed to evaluate the safety and efficacy of bardoxolone methyl in patients with Alport syndrome. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We randomly assigned patients with Alport syndrome, ages 12-70 years and eGFR 30-90 ml/min per 1.73 m2, to bardoxolone methyl (n=77) or placebo (n=80). Primary efficacy end points were change from baseline in eGFR at weeks 48 and 100. Key secondary efficacy end points were change from baseline in eGFR at weeks 52 and 104, after an intended 4 weeks off treatment. Safety was assessed by monitoring for adverse events and change from baseline in vital signs, 12-lead electrocardiograms, laboratory measurements (including, but not limited to, aminotransferases, urinary albumin-creatinine ratio, magnesium, and B-type natriuretic peptide), and body weight. RESULTS: Patients randomized to bardoxolone methyl experienced preservation in eGFR relative to placebo at 48 and 100 weeks (between-group differences: 9.2 [97.5% confidence interval, 5.1 to 13.4; P<0.001] and 7.4 [95% confidence interval, 3.1 to 11.7; P=0.0008] ml/min per 1.73 m2, respectively). After a 4-week off-treatment period, corresponding mean differences in eGFR were 5.4 (97.5% confidence interval, 1.8 to 9.1; P<0.001) and 4.4 (95% confidence interval, 0.7 to 8.1; P=0.02) ml/min per 1.73 m2 at 52 and 104 weeks, respectively. In a post hoc analysis with no imputation of missing eGFR data, the difference at week 104 was not statistically significant (1.5 [95% confidence interval, -1.9 to 4.9] ml/min per 1.73 m2). Discontinuations from treatment were more frequent among patients randomized to bardoxolone methyl; most discontinuations were due to protocol-specified criteria being met for increases in serum transaminases. Serious adverse events were more frequent among patients randomized to placebo. Three patients in each group developed kidney failure. CONCLUSIONS: In adolescent and adult patients with Alport syndrome receiving standard of care, treatment with bardoxolone methyl resulted in preservation in eGFR relative to placebo after a 2-year study period; off-treatment results using all available data were not significantly different. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: A Phase 2/3 Trial of the Efficacy and Safety of Bardoxolone Methyl in Patients with Alport Syndrome - CARDINAL (CARDINAL), NCT03019185.

Novel Renal Autologous Cell Therapy for Type 2 Diabetes Mellitus Chronic Diabetic Kidney Disease: Clinical Trial Design.

BACKGROUND: Cell therapies explore unmet clinical needs of patients with chronic kidney disease with the potential to alter the pathway toward end-stage kidney disease. We describe the design and baseline patient characteristics of a phase II multicenter clinical trial utilizing the novel renal autologous cell therapy (REACT), by direct kidney parenchymal injection via the percutaneous approach in adults with type 2 diabetic kidney disease (T2DKD), to delay or potentially avoid renal replacement therapy. DESIGN: The study conducted a prospective, multicenter, randomized control, open-label, phase II clinical trial between an active treatment group (ATG) receiving REACT from the beginning of the trial and a contemporaneous deferred treatment group (DTG) receiving standard of care for 12 months before crossing over to receive REACT. OBJECTIVES: The objective of this study was to establish the safety and efficacy of 2 REACT injections with computed tomography guidance, into the renal cortex of patients with T2DKD administered 6 months apart, and to compare the longitudinal change in renal function between the ATG and the DTG. SETTING: This was a multicenter study conducted in major US hospitals. PATIENTS: We enrolled eighty-three adult patients with T2DKD, who have estimated glomerular filtration rates (eGFRs) between 20 and 50 mL/min/1.73 m2. METHODS: All patients undergo an image-guided percutaneous kidney biopsy to obtain epithelial phenotype selective renal cells isolated from the kidney tissue that is then expanded ex vivo over 4-6 weeks, resulting in the REACT biologic product. Patients are randomized 1:1 into the ATG or the DTG. Primary efficacy endpoints for both study groups include eGFR measurements at baseline and at 3-month intervals, through 24 months after the last REACT injection. Safety analyses include biopsy-related complications, REACT injection, and cellular-related adverse events. The study utilizes Good Clinical and Manufacturing Practices and a Data and Safety Monitoring Board. The sample size confers a statistical power of 80% to detect an eGFR change in the ATG compared to the DTG at 24 months with an α = 0.05. LIMITATIONS: Blinding cannot occur due to the intent to treat procedure, biopsy in both groups, and open trial design. CONCLUSION: This multicenter phase II randomized clinical trial is designed to determine the efficacy and safety of REACT in improving or stabilizing renal function among patients with T2DKD stages 3a-4.

Study Design and Baseline Characteristics of the CARDINAL Trial: A Phase 3 Study of Bardoxolone Methyl in Patients with Alport Syndrome.

INTRODUCTION: Alport syndrome is a rare genetic disorder that affects as many as 60,000 persons in the USA and a total of 103,000 persons (<5 per 10,000) in the European Union [1, 2]. It is the second most common inherited cause of kidney failure and is characterized by progressive loss of kidney function that often leads to end-stage kidney disease. Currently, there are no approved disease-specific agents for therapeutic use. We designed a phase 3 study (CARDINAL; NCT03019185) to evaluate the safety, tolerability, and efficacy of bardoxolone methyl in patients with Alport syndrome. METHODS: The CARDINAL phase 3 study is an international, multicenter, double-blind, placebo-controlled, randomized registrational trial. Eligible patients were of ages 12-70 years with confirmed genetic or histologic diagnosis of Alport syndrome, eGFR 30-90 mL/min/1.73 m2, and urinary albumin to creatinine ratio (UACR) ≤3,500 mg/g. Patients with B-type natriuretic peptide values >200 pg/mL at baseline or with significant cardiovascular histories were excluded. Patients were randomized 1:1 to bardoxolone methyl or placebo, with stratification by baseline UACR. RESULTS: A total of 371 patients were screened, and 157 patients were randomly assigned to receive bardoxolone methyl (n = 77) or placebo (n = 80). The average age at screening was 39.2 years, and 23 (15%) were <18 years of age. Of the randomized population, 146 (93%) had confirmed genetic diagnosis of Alport syndrome, and 62% of patients had X-linked mode of inheritance. Mean baseline eGFR was 62.7 mL/min/1.73 m2, and the geometric mean UACR was 141.0 mg/g. The average annual rate of eGFR decline prior to enrollment in the study was -4.9 mL/min/1.73 m2 despite 78% of the patient population receiving ACE inhibitor (ACEi) or ARB therapy. DISCUSSION/CONCLUSION: CARDINAL is one of the largest interventional, randomized controlled trials in Alport syndrome conducted to date. Despite the use of ACEi or ARB, patients were experiencing significant loss of kidney function prior to study entry.

Safety and Efficacy of Tenapanor for Long-term Serum Phosphate Control in Maintenance Dialysis: A 52-Week Randomized Phase 3 Trial (PHREEDOM).

Background: Treating hyperphosphatemia is a tenet of dialysis care. This trial assessed the safety and efficacy of tenapanor for the management of hyperphosphatemia. Methods: In this 52-week phase 3 study (NCT03427125), participants receiving maintenance dialysis with both hyperphosphatemia (serum phosphate 6.0-10.0 mg/dl) and a 1.5 mg/dl increase after phosphate binder washout were randomized (3:1) to tenapanor 30 mg twice daily for 26 weeks (randomized treatment period) or sevelamer carbonate (52-week safety control). Participants completing 26 weeks of treatment with tenapanor were rerandomized (1:1) to tenapanor or placebo for 12 weeks (randomized withdrawal period), and were eligible to enter the 14-week safety extension period. With input from the US Food and Drug Administration, the primary efficacy end point was the difference in the change in serum phosphate from the end of the randomized treatment period to the end of the randomized withdrawal period, among participants who achieved ≥1.2 mg/dl decrease in serum phosphate during the randomized treatment period (efficacy analysis set). Efficacy was also evaluated in the intention-to-treat (ITT) analysis set. Results: Of 564 eligible participants randomized to receive tenapanor (n=423) or sevelamer carbonate (n=141) during the randomized treatment period, 255 (60%) in the tenapanor group subsequently were rerandomized to tenapanor (n=128) or placebo (n=127) during the randomized withdrawal period. In the efficacy analysis set (n=131), the difference in estimated mean change in serum phosphate level between tenapanor and placebo from the beginning to the end of the randomized withdrawal period was -1.4 mg/dl (P<0.0001); in the ITT analysis set (n=243), the estimated mean difference was -0.7 mg/dl (P=0.002). Loosened stools were the most frequently reported adverse event (53% during the randomized treatment period). Serious adverse events were reported more frequently for participants treated with sevelamer carbonate (16%-23% across the three study periods) compared with tenapanor (11%-17%). Conclusions: Tenapanor reduced serum phosphate concentrations and maintained control of serum phosphate in participants receiving maintenance dialysis, with an acceptable safety and tolerability profile.

Effects of Bardoxolone Methyl on Magnesium in Patients with Type 2 Diabetes Mellitus and Chronic Kidney Disease.

BACKGROUND: Treatment with bardoxolone methyl (Bard) in a multinational phase 3 trial, Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), resulted in increases in estimated glomerular filtration rate with concurrent reductions in serum magnesium. We analyzed data from several trials to characterize reductions in magnesium with Bard. METHODS: BEACON randomized patients (n = 2,185) with type 2 diabetes (T2DM) and stage 4 chronic kidney disease (CKD) 1:1 to receive Bard (20 mg) or placebo once daily. In a separate open-label study, magnesium levels from 24-hour urine and sublingual epithelial cell samples were analyzed in patients with stage 3b-4 CKD and T2DM administered 20 mg Bard for 56 consecutive days. RESULTS: BEACON patients randomized to Bard experienced significant reductions in serum magnesium from baseline relative to patients randomized to placebo (-0.17 mEq/L, 95% CI -0.18 to -0.60 mEq/L; p < 0.001). A separate study showed intracellular and urinary magnesium levels were unchanged with Bard treatment. CONCLUSIONS: Bard treatment results in significant decreases in serum magnesium that are not associated with changes in intracellular and urinary magnesium levels, indicating that magnesium decreases are not due to renal magnesium wasting or total body magnesium depletion. Importantly, the decreases in serum magnesium with Bard are not associated with adverse effects on QT interval.

Effects of bardoxolone methyl on body weight, waist circumference and glycemic control in obese patients with type 2 diabetes mellitus and stage 4 chronic kidney disease.

AIMS: Obesity is associated with progression of chronic kidney disease (CKD). Treatment with bardoxolone methyl in a multinational phase 3 trial, Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), resulted in increases in estimated glomerular filtration rate (eGFR) with concurrent reductions in body weight. We performed post-hoc analyses to further characterize reductions in body weight with bardoxolone methyl. METHODS: Eligible patients with type 2 diabetes (T2DM) and CKD stage 4 (eGFR 15 to <30 mL/min/1.73 m2) were randomized 1:1 to receive once-daily oral dose of bardoxolone methyl (20 mg) or placebo. RESULTS: BEACON enrolled 2185 patients. Patients randomized to bardoxolone methyl experienced significant reductions in body weight from baseline relative to patients randomized to placebo (-5.7 kg; 95% CI: -6.0 to -5.3 kg; p < 0.001). In patients randomized to bardoxolone methyl, rate and magnitude of body weight loss were proportional to baseline BMI. Bardoxolone methyl resulted in significant reductions in waist circumference and improved glycemic control. CONCLUSIONS: Bardoxolone methyl resulted in significant weight loss in a generally obese patient population with T2DM and stage 4 CKD, with the magnitude and rate dependent on baseline BMI.

Modified-release calcifediol effectively controls secondary hyperparathyroidism associated with vitamin D insufficiency in chronic kidney disease.

BACKGROUND/AIMS: Vitamin D insufficiency drives secondary hyperparathyroidism (SHPT) and is associated with increased cardiovascular mortality in patients with chronic kidney disease (CKD). SHPT is poorly addressed by current vitamin D repletion options. The present study evaluated a novel investigational vitamin D repletion therapy: a modified-release (MR) formulation of calcifediol designed to raise serum 25-hydroxyvitamin D in a gradual manner to minimize the induction of CYP24 and, thereby, improve the SHPT control. METHODS: This randomized, double-blind, placebo-controlled trial evaluated MR calcifediol in CKD subjects (n = 78) with plasma intact parathyroid hormone (iPTH) >70 pg/ml and serum total 25-hydroxyvitamin D <30 ng/ml. Subjects received daily treatment for six weeks with oral MR calcifediol (30, 60 or 90 µg) or a placebo. RESULTS: More than 90% of subjects treated with MR calcifediol achieved serum 25-hydroxyvitamin D levels ≥30 ng/ml versus 3% of subjects treated with placebo (p < 0.0001). Mean plasma iPTH decreased from baseline (140.3 pg/ml) by 20.9 ± 6.2% (SE), 32.8 ± 5.7 and 39.3 ± 4.3% in the 30, 60 and 90 µg dose groups, respectively, and increased 17.2 ± 7.8% in the pooled placebo group (p < 0.005). No clinically significant safety concerns arose during MR calcifediol treatment. CONCLUSION: Oral MR calcifediol appears safe and highly effective in treating SHPT associated with vitamin D insufficiency in CKD.

Effects of cinacalcet on bone mineral density in patients with secondary hyperparathyroidism.

BACKGROUND: Cinacalcet, a calcimimetic agent, is effective in treating both primary and secondary hyperparathyroidism. Because hyperparathyroidism induces mineralized bone loss, we investigated the effects of cinacalcet treatment on bone mineral density (BMD) in patients with secondary hyperparathyroidism due to chronic kidney disease. METHODS: Ten patients who were receiving haemodialysis and four patients, who had stage 4 chronic kidney disease participated and completed the multicentre, randomized, double-blind, placebo-controlled trials evaluating the safety and efficacy of cinacalcet for treating secondary hyperparathyroidism. The efficacy of cinacalcet was assessed by plasma intact parathyroid hormone (iPTH) levels. A dual energy X-ray absorptiometry was performed to measure the BMD of total proximal femurs and lumbar spine (L2-L4) before and after 26 weeks of treatment. RESULTS: Cinacalcet reduced iPTH from 912+/-296 to 515+/-359 pg/ml in haemodialysis patients and from 210+/-46 to 56+/-51 pg/ml in pre-dialysis patients (means+/-SD; both P<0.05). When data from haemodialysis and pre-dialysis patients were pooled for analysis, cinacalcet treatment increased proximal femur BMD from 0.945+/-0.169 to 0.961+/-0.174 g/cm(2) (P<0.05), but did not affect lumbar spine BMD. There was a correlation between the change in femur BMD and the change in iPTH during the study period (R(2) = 0.39, P<0.05). CONCLUSIONS: Secondary hyperparathyroidism is associated with progressive bone loss. Suppression of plasma iPTH with cinacalcet appears to reverse bone loss in the proximal femur, but does not affect BMD of the lumbar spine. A larger study is warranted to confirm that cinacalcet has a beneficial effect on the skeletal system in patients with secondary hyperparathyroidism.

Pathogenesis of renal ischemia/reperfusion injury: lessons from knockout mice.

Ischemia/reperfusion-induced acute renal failure is a common clinical problem associated with a high morbidity and mortality. Upon hypoxic injury, the depletion of ATP causes mitochondrial dysfunction, and accumulation of intracellular sodium, calcium and reactive oxygen species. Subsequently, multiple enzyme systems including proteases, nitric oxide synthases, phospholipases and endonuclease are activated and responsible for cytoskeleton disruption, membrane damage, and DNA degradation, and eventually cell death. Ischemia/reperfusion injury also activates complement, cytokines, and chemokines, which are cytotoxic themselves, but also attract leukocytes into the ischemic area to cause further damage. The vascular endothelial cell injury and dysfunction prolong ischemia and induce vascular congestion, edema, and further infiltration of inflammatory cells. Many players in renal ischemia/reperfusion injury and their mechanisms have been investigated using genetically manipulated mouse models. In this review, we focus on the information gathered from these studies. Deficiency of the Na/Ca exchanger, inducible nitric oxide synthase, Caspase-1, A3 adenosine receptor, C3, C5, C6, Factor B, or midkine protects the kidney against I/R injury. Conversely, deficiency of the interleukin-1 receptor, osteopontin, C4, or recombination activation gene-1 is not protective, while the absence of adrenomedullin or endothelin receptor B delays the recovery of ischemia/reperfusion injury. The knowledge obtained from these studies provides new direction for designing potential therapeutic agents for treating ischemia/reperfusion injury.