A Two-Part, Single-Blind, Phase 3 Study Evaluating the Efficacy and Safety of Patiromer for the Treatment of Hyperkalemia (OPAL)

A Two-Part, Single-Blind, Phase 3 Study Evaluating the Efficacy and Safety of Patiromer for the Treatment of Hyperkalemia

The purpose of this study was to evaluate the efficacy and safety of patiromer (investigational drug) in the treatment of hyperkalemia (high serum potassium). The study also evaluated the effect of withdrawing patiromer treatment and assessed whether chronic treatment with patiromer prevented the recurrence of hyperkalemia. The safety of patiromer treatment was also evaluated.

There were two parts in the study, Part A and Part B.

Part A was an assessment of 4 weeks of dosing with patiromer in the treatment of hyperkalemia; Part B was a randomized, placebo-controlled, 8-week assessment of the withdrawal of patiromer in participants with a baseline serum potassium at the beginning of Part A ≥ 5.5 mEq/L who responded to the 4 weeks of treatment with patiromer during Part A.

All participants received patiromer during Part A; Part B participants were randomized to continue patiromer or switch to placebo. Total study participation was up to 14 weeks (including up to 2 weeks of follow up).

The dose of patiromer could be titrated based on participant's serum potassium response.

Inclusion Criteria:

• Males and females ages 18 - 80
• Chronic kidney disease (CKD) - eGFR 15 to < 60 mL/min/1.73m2 at screening
• Hyperkalemia, defined as a serum potassium value of 5.1 to < 6.5 mEq/L at screening
• Taking either an Angiotensin-Converting Enzyme (ACE) Inhibitor, an Angiotensin II receptor blocker (ARB), or an aldosterone antagonist (AA) medication
• Informed consent given

Exclusion Criteria:

• Participants with auto-immune related chronic kidney disease such as lupus nephritis or renal scleroderma/scleroderma renal crisis, or mixed connective tissue disease with renal involvement
• Participants with uncontrolled Type 1 diabetes, defined as or a HbA1c > 10.0 %, or hospitalization to treat hyper- or hypo-glycemia in the past 3 months within the previous 6 months in participants with Type 2 diabetes
• Participants with severe heart failure, defined as NYHA (New York Heart Association) class IV
• Participants with major surgery including thoracic and cardiac, in the past 3 months, or participants with heart or kidney transplant
• Participants with significant cardiovascular or cerebrovascular events in the past 2 months, such as cardiac arrest, myocardial infarction, or stroke
• Participants with BMI ≥ 40 kg/m2