Matthew R. Weir
WASHINGTON — Patiromer was effective in controlling serum potassium in hyperkalemic patients with diabetes and advanced kidney disease on renin-angiotensin-aldosterone system inhibitors, according to research presented here.
“I think the real opportunity for these new potassium-binding drugs is to enable nephrologists to expand the use of renal angiotensin-resistant blockade, even with mineralocorticoid receptor antagonism in people with kidney disease and, unfortunately, if they have heart disease as well,” Matthew R. Weir, MD, director of the division of nephrology at the University of Maryland School of Medicine, told Healio/Nephrology.
Weir presented results from the AMETHYST-DN trial on the efficacy and safety of patiromer, a non-absorbed potassium binder approved for the treatment of hyperkalemia. The trial examined whether patiromer was effective in controlling serum potassium (sK) while maintaining renin-angiotensin-aldosterone system (RAAS) inhibitor therapy in younger and older adult patients.
Weir said that most patients in the study were responsive to the initial dose of patiromer. “What is fascinating about these new serum potassium binders is that with chronic usage, the potassium tends to settle out at 4.6 [mEq/L] pretty consistently,” Weir told Healio/Nephrology. “Whether the serum potassium at the start is over 6 [mEq/L] or under 6 [mEq/L] it doesn’t really matter, ... but 80% of patients will achieve the 4.6 [mEq/L] on the initial starting dose; the other 20% may need a higher dose.”
“I think that is the gist of the observations from the study,” he said.
The 52-week, multicenter, open-label trial involved 304 patients with an eGFR of 15 mL/min/1.73m2 to less than 60 mL/min/1.73m2; type 2 diabetes, hypertension and documented hyperkalemia (sK > 5 mEq/L). Patiromer was titrated, if needed, to achieve and maintain serum potassium of less than or equal to 5 mEq/L.
In the patient group, 122 were younger than 65 years; 122 were between the ages of 65 and 75 years and 60 patients were older than 75 years. All were randomized and received one or more doses of patiromer.
Within 3 days of dosing, and with baseline mean sK levels of 5.32±0.35 mEq/L, 5.31±0.37 mEq/L, and 5.19±0.38 mEq/L mEq/L, respectively, in the three age groups, mean sK levels were reduced (4.97±0.42 mEq/L, 4.90±0.44 mEq/L, 4.89±0.45 mEq/L, respectively).
“The real opportunity is to get more people to guideline-based therapy so that we can take advantage of the impact of this therapy on long-term outcomes, both in terms of kidney disease progression and in terms of heart failure progression,” Weir said. “People need to develop a level of comfort, a level of experience with these drugs to treat hyperkalemia.”– by Kristine Houck, MA, ELS, and Mark E. Neumann
Weir MR, et al. FR-PO255. Presented at: ASN Kidney Week; Nov. 7-10, 2019; Washington, D.C.
Disclosures: Weir reports he has served as an advisor for Relypsa, a Vifor Pharma Group company, and for AstraZeneca. Other authors on this study are employed by Relypsa.