Patiromer Effectiveness in Hyperkalemia Unaffected by RAASi Use
Patiromer’s potassium-lowering effect in patients with hyperkalemia is similar regardless of whether or not they are taking renin-angiotensin-aldosterone system inhibitors.
Patiromer is effective and generally well tolerated for treating hyperkalemia, regardless of whether patients were taking renin-angiotensin-aldosterone system inhibitors (RAASi), which are associated with a higher incidence of hyperkalemia, according to a new report.
The finding is from a post-hoc analysis of the TOURMALINE study, a phase 4 prospective open-label trial comparing the efficacy and safety of patiromer administered with vs without food. The trial demonstrated that patiromer, a non-absorbed potassium-binding polymer that uses calcium as a counterexchange ion, lowers serum potassium in patients with hyperkalemia. Unlike in previous studies, patients in the TOURMALINE study were not required to be taking RAASi. The latest analysis is the first report of patiromer in patients not taking RAASi, Robert A. Kloner, MD, PhD, of the Keck School of Medicine at the University of Southern California, and colleagues stated in a paper published recently online ahead of print in the Journal of Cardiovascular Pharmacology and Therapeutics. The primary end point was the proportion of patients with serum potassium levels of 3.8 to 5.0 mEq/L at week 3 or 4.
Of 114 patients randomized, 67 (59%) were taking RAASi at baseline and 47 (41%) were not. At baseline, the mean serum potassium level was 5.37 and 5.42 mEq/L in patients taking and not taking RAASi, respectively. The primary end point was achieved in 85% and 84% of the RAASi and non-RAASi groups, respectively, a difference that was not statistically significant.
“We show for the first time that patiromer appears to be equally effective and well tolerated when used without or with RAASi,” the authors concluded.
The primary end point was achieved with a similar number and extent of dose titrations of patiromer in both patient groups, the authors noted. The mean daily patiromer doses were similar in the RAASi and non-RAASi groups: 10.7 and 11.5 grams, respectively.
Adverse events were reported in 26 patients (39%) in the RAASi group and 25 (54%) in the non-RAASi group, according to Dr Kloner's team. The mean daily dose prescribed at week 3—the last titrated dose—was 12.5 and 13.9 grams, respectively.
Kloner RA, Gross C, Yuan J, et al. Effect of patiromer in hyperkalemic patients taking and not taking RAAS inhibitors. J Cardiovasc Pharmacol Ther. 2018; published online ahead of print.