In patients with chronic kidney disease who were receiving RAAS inhibitors and who had hyperkalemia, patiromer treatment was associated with a decrease in serum potassium levels and, as compared with placebo, a reduction in the recurrence of hyperkalemia. (Funded by Relypsa; OPAL-HK ClinicalTrials.gov number, NCT01810939.).

IMPORTANCE Hyperkalemia is a potentially life-threatening condition predominantly seen in patients treated with renin-angiotensin-aldosterone system (RAAS) inhibitors with stage 3 or greater chronic kidney disease (CKD) who may also have diabetes, heart failure, or both. OBJECTIVES To select starting doses for a phase 3 study and to evaluate the long-term safety and efficacy of a potassium-binding polymer, patiromer, in outpatients with hyperkalemia. DESIGN, SETTING, AND PARTICIPANTS Phase 2, multicenter, open-label, dose-ranging, randomized clinical trial (AMETHYST-DN), conducted at 48 sites in Europe from June 2011 to June 2013 evaluating patiromer in 306 outpatients with type 2 diabetes (estimated glomerular filtration rate, 15 to <60 mL/min/1.73 m 2 and serum potassium level >5.0 mEq/L). All patients received RAAS inhibitors prior to and during study treatment. INTERVENTIONS Patients were stratified by baseline serum potassium level into mild or moderate hyperkalemia groups and received 1 of 3 randomized starting doses of patiromer (4.2 g [n = 74], 8.4 g [n = 74], or 12.6 g [n = 74] twice daily [mild hyperkalemia] or 8.4 g [n = 26], 12.6 g [n = 28], or 16.8 g [n = 30] twice daily [moderate hyperkalemia]). Patiromer was titrated to achieve and maintain serum potassium level 5.0 mEq/L or lower. MAIN OUTCOMES AND MEASURES The primary efficacy end point was mean change in serum potassium level from baseline to week 4 or prior to initiation of dose titration. The primary safety end point was adverse events through 52 weeks. Secondary efficacy end points included mean change in serum potassium level through 52 weeks. RESULTS A total of 306 patients were randomized. The least squares mean reduction from baseline in serum potassium level at week 4 or time of first dose titration in patients with mild hyperkalemia was 0.35 (95% CI, 0.22-0.48) mEq/L for the 4.2 g twice daily starting-dose group, 0.51 (95% CI, 0.38-0.64) mEq/L for the 8.4 g twice daily starting-dose group, and 0.55 (95% CI, 0.42-0.68) mEq/L for the 12.6 g twice daily starting-dose group. In those with moderate hyperkalemia, the reduction was 0.87 (95% CI, 0.60-1.14) mEq/L for the 8.4 g twice daily starting-dose group, 0.97 (95% CI, 0.70-1.23) mEq/L for the 12.6 g twice daily starting-dose group, and 0.92 (95% CI, 0.67-1.17) mEq/L for the 16.8 g twice daily starting-dose group (P < .001 for all changes vs baseline by hyperkalemia starting-dose groups within strata). From week 4 through week 52, statistically significant mean decreases in serum potassium levels were observed at each monthly point in patients with mild and moderate hyperkalemia. Over the 52 weeks, hypomagnesemia (7.2%) was the most common treatment-related adverse event, mild to moderate constipation (6.3%) was the most common gastrointestinal adverse event, and hypokalemia (<3.5 mEq/L) occurred in 5.6% of patients. CONCLUSIONS AND RELEVANCE Among patients with hyperkalemia and diabetic kidney disease, patiromer starting doses of 4.2 to 16.8 g twice daily resulted in statistically signific...

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Fabry disease, an inherited deficiency of the lysosomal enzyme ␣-galactosidase A, causes progressive intralysosomal accumulation of globotriaosylceramide (GL-3) and premature death from renal, cardiac, and cerebrovascular manifestations. To determine the long-term safety and efficacy of recombinant human ␣-galactosidase A, an open-label, phase III extension study was conducted, involving 58 patients who had classic Fabry disease and completed a 20-wk, double-blind, randomized, placebo-controlled, phase III study of agalsidase ␤ and were transitioned to an extension trial to receive biweekly 1 mg/kg agalsidase ␤ for up to an additional 54 mo. GL-3 accumulation was evaluated in the capillary endothelia of the skin, kidney, and heart. Renal function was assessed. By month 54, all patients with optional kidney biopsies (n ‫؍‬ 8) maintained complete GL-3 clearance in renal capillary endothelial cells and multiple cell types. Continued, complete clearance of skin (31 of 36) and heart (six of eight) capillary endothelium was demonstrated. Mean plasma GL-3 levels remained decreased in the normal range. Median serum creatinine and estimated GFR remained stable (normal) in patients with renal data at month 54 (n ‫؍‬ 41). Six patients had renal disease progression; most (four of six) were older than 40 yr and had significant proteinuria at baseline and evidence of sclerotic glomeruli pretreatment. Adverse events were generally mild and unrelated to treatment. The most common treatment-related adverse events were infusion-associated reactions, which decreased over time. Long-term agalsidase ␤ therapy stabilizes renal function in patients without renal involvement at baseline, maintains reduction of plasma GL-3, and sustains GL-3 clearance in capillary endothelial cells and multiple renal cell types.

AimsTo evaluate efficacy and safety of RLY5016 (a non-absorbed, orally administered, potassium [K+]-binding polymer) on serum K+ levels in patients with chronic heart failure (HF) receiving standard therapy and spironolactone.Methods and resultsOne hundred and five patients with HF and a history of hyperkalaemia resulting in discontinuation of a renin–angiotensin–aldosterone system inhibitor/blocker and/or beta-adrenergic blocking agent or chronic kidney disease (CKD) with an estimated glomerular filtration rate of <60 mL/min were randomized to double-blind treatment with 30 g/day RLY5016 or placebo for 4 weeks. Spironolactone, initiated at 25 mg/day, was increased to 50 mg/day on Day 15 if K+ was ≤5.1 mEq/L. Endpoints included the change from baseline in serum K+ at the end of treatment (primary); the proportion of patients with hyperkalaemia (K+ >5.5 mEq/L); and the proportion titrated to spironolactone 50 mg/day. Safety assessments included adverse events (AEs) and clinical laboratory tests. RLY5016 (n= 55) and placebo (n= 49) patients had similar baseline characteristics. At the end of treatment, compared with placebo, RLY5016 had significantly lowered serum K+ levels with a difference between groups of −0.45 mEq/L (P < 0.001); a lower incidence of hyperkalaemia (7.3% RLY5016 vs. 24.5% placebo, P= 0.015); and a higher proportion of patients on spironolactone 50 mg/day (91% RLY5016 vs. 74% placebo, P= 0.019). In patients with CKD (n= 66), the difference in K+ between groups was −0.52 mEq/L (P= 0.031), and the incidence of hyperkalaemia was 6.7% RLY5016 vs. 38.5% placebo (P= 0.041). Adverse events were mainly gastrointestinal, and mild or moderate in severity. Adverse events resulting in study withdrawal were similar (7% RLY5016, 6% placebo). There were no drug-related serious AEs. Hypokalaemia (K+ <3.5 mEq/L) occurred in 6% of RLY5016 patients vs. 0% of placebo patients (P= 0.094).ConclusionRLY5016 prevented hyperkalaemia and was relatively well tolerated in patients with HF receiving standard therapy and spironolactone (25–50 mg/day) (ClinicalTrials.gov registry identifier: NCT00868439).