|The following article features coverage from the National Kidney Foundation’s virtual 2020 Spring Clinical Meetings. Click here to read more of Renal and Urology News’ conference coverage.|
Patiromer, a potassium binder approved for treating hyperkalemia, enables more patients with both advanced chronic kidney disease (CKD) and resistant hypertension to continue on therapy with spironolactone, including those aged 65 and older, according to study findings presented at the live virtual 2020 National Kidney Foundation’s virtual Spring Clinical Meetings.
The findings are from an analysis of patients with advanced CKD in the AMBER trial, a randomized, double-blind, placebo-controlled 12-week study that compared patiromer plus spironolactone with placebo plus spironolactone. The original results, published in The Lancet in 2019, demonstrated that significantly more patients treated with patiromer than with placebo remained on spironolactone at week 12 and the cumulative dose of spironolactone was significantly higher in patiromer-treated patients.
Use of renin-angiotensin-aldosterone system inhibitors (RAASi) increases the risk of hyperkalemia, especially in older patients with reduced aldosterone production, decreased glomerular filtration rate, and impaired renal tubular function, AMBER investigators led by Rajiv Agarwal, MD, of the Indiana University School of Medicine in Indianapolis, explained. Spironolactone is effective at reducing blood pressure in patients with uncontrolled resistant hypertension, but the use of this drug in patients with CKD can be restricted by hyperkalemia.
For the new analysis, Dr Agarwal and his collaborators analyzed data from prespecific subgroups by age: less than 65 years and 65 years or older. Of 295 patients randomized for the trial, 93 (31.5%) were younger than age 65 and 202 (68.5%) were aged 65 or older.
As in the original AMBER analysis, a significantly higher proportion of patiromer-treated patients than placebo recipients remained on spironolactone. In the younger subgroup, 30 (68.2%) of 44 patients in the placebo arm remained on spironolactone at week 12 compared with 44 (89.8%) of 49 patiromer recipients, a 21.6% difference in proportions, Dr Agarwal’s group reported in a poster presentation. In the older subgroup, 68 (64.4%) of the 104 patients in the placebo group remained on spironolactone at week 12 compared with 82 (83.7%) of 98 patients treated with patiromer, an 18.3% difference in proportions.
The investigators also looked a subgroup of 107 patients aged 75 years or older (53 in the placebo arm and 54 in the patiromer arm). At week 12, 33 placebo recipients (62%) and 45 (83%) patiromer-treated patients remained on spironolactone.
In the younger subgroup, a serum potassium level of 5.5 mEq/L or higher occurred in 30 patients (68%) receiving placebo and 23 patients (47%) receiving patiromer. Among the patients aged 65 years and older, a serum potassium level of 5.5 mEq/L or higher occurred in 68 patients (65%) of placebo recipients and in 30 patients (31%) receiving patiromer.
At week 12, the mean serum potassium level in the younger patients was 4.74 mEq/L in the placebo arm and 4.76 mEq/L in the patiromer group. In the older patients, the mean serum potassium level at week 12 was 4.98 mEq/L in the placebo recipients and 4.75 mEq/L in the patriomer group.
The age subgroups had similar rates of any adverse events (AEs) and serious AEs.
Disclosure: The study was supported by Relypsa, Inc., the maker of patiromer.
Read more of our coverage of the National Kidney Foundation’s virtual 2020 Spring Clinical Meetings by visiting the conference page.
Agarwal R, Rossignol P, Arthur S, et al. Patiromer vs placebo to enable spironolactone in patients with resistant hypertension and CKD according to patient age (AMBER trial). Data presented at the live virtual 2020 National Kidney Foundation Spring Clinical Meetings held March 25 to 29. ePoster 401.