US-based biopharmaceutical firm ZS Pharma has completed patient enrolment in its second randomised, double-blind, placebo-controlled Phase III clinical trial (ZS004) of ZS-9 (sodium zirconium cyclosilicate), a new investigational treatment for hyperkalemia.
The trial is designed to confirm, over a longer treatment period, the positive results previously reported for ZS003, a Phase III trial in which once-daily doses of ZS-9 maintained potassium levels within the normal range with safety and tolerability similar to placebo.
The company enrolled a total of 258 patients with hyperkalemia at 42 participating sites in the ZS004 trial that started in March.
Currently, the company expects to report top-line results from ZS004 late in the third quarter or early in the fourth quarter of 2014 and plans to present the full data at medical conferences.
ZS Pharma chief executive officer Robert Alexander said: "Completion of enrolment in ZS004 is a key step in advancing the ZS-9 global development programme toward planned NDA and MAA submissions in the first half of 2015.
"It also brings us one step closer to potentially making ZS-9 available to patients who need new treatment options for hyperkalemia."
The trial included patients with hyperkalemia (potassium levels >5 mEq/L), including patients with chronic kidney disease (CKD), heart failure, diabetes, and those on renin angiotensin aldosterone system (RAAS) inhibitor therapy.
In the open-label induction phase of the Phase III trial, patients were given 10g of ZS-9 administered three times daily for 48 hours.
Patients who achieved normokalemia were eligible to be randomised in a double-blind fashion to one of three doses of ZS-9 (5g, 10g or 15g) or placebo administered once-daily for 28 days.
The trial's primary efficacy endpoint is a comparison of the mean serum potassium level of each ZS-9 treatment group compared with that of placebo over the randomized withdrawal period.
In conjunction with ZS004, the company is also carrying out ZS004E, an extension trial that will generate longer-term open-label safety, tolerability and efficacy data in patients who participated in ZS004.
In ZS004E, patients will be given an additional five months of treatment, resulting in a combined potential of six months of treatment with ZS-9 over the course of ZS004 and ZS004E.