Background: Patiromer (PAT) is a sodium-free, non-absorbed potassium (K+) binder approved for the treatment of hyperkalemia (HK). HK is common in older patients (pts) with cardiorenal comorbidities and often limits the use of guideline recommended renin-angiotensin-aldosterone system inhibitor (RAASi) medications. We previously reported the design and results for AMETHYST-DN, a phase 2 multicenter, open-label, 52 week randomized clinical trial in a large cohort of adult pts (n=306; 30-80 years of age).

Methods: Here we report the results in a subgroup ≥75 years of age with type 2 DM, chronic kidney disease (CKD) (eGFR 15 to <60 mL/min/1.73 m2), hypertension and serum (s) K+ >5.0 mEq/L (n=60). All pts received a RAASi before and during the study treatment and PAT was titrated to maintain sK+ in the normal range.

Results: Two days after the first dose, mean sK+ was reduced to 4.89 mEq/L from a baseline (BL) mean of 5.19 mEq/L (p<0.001). The least square mean reduction in sK+ from BL to week 4 was -0.65 mEq/L (p<0.001) and -0.61 mEq/L (p<0.001) at 52 weeks (end of treatment). The % of pts with sK+ in the normal range (3.8-5.0 mEq/L) between weeks 12-52 ranged from 88-98%. At the end of treatment, 92% of pts had sK+ in the normal range. The most common GI-related adverse event (AE) was constipation observed in 2 pts (3.3%). Serum magnesium levels of <1.2 mg/dL were seen in 3 pts (5%). Hypokalemia (sK+ <3.5 mEq/L) did not occur in this older population. Serious AEs were reported for 9 pts (15%); none attributed to PAT by investigator. Study limitations include a lack of blinding, a lack of comparator, and a lack of diversity.

Conclusions: In this subgroup of pts ≥75 years with diabetic CKD receiving a RAASi medication, PAT reduced and maintained control of sK+ for up to 1 year. PAT was well tolerated over 52 weeks with no serious AEs attributed to its use. These results suggest that PAT may facilitate the use of RAASi medications in older pts likely to benefit from their cardiorenal protective effects.


G.L. Bakris: Consultant; Self; Merck & Co., Inc., Novo Nordisk Inc., Relypsa, Inc. Research Support; Self; Bayer AG, Janssen Pharmaceuticals, Inc. S.D. Woods: Employee; Self; Relypsa, Inc. P.J. Alvarez: Employee; Self; Relypsa, Inc. J. Fogli: Employee; Self; Relypsa, Inc. S. Arthur: Employee; Self; Relypsa, Inc. M.R. Mayo: Employee; Self; Relypsa, Inc. R. Kumar: None.


Relypsa, Inc.

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