US-based pharmaceutical firm ZS Pharma has released positive top-line results from the acute phase of the randomised, double-blind, Phase III clinical study of ZS-9 called ‘ZS-003’ for the treatment of hyperkalemia, a life-threatening metabolic condition that can lead to cardiac arrhythmia and sudden death.
A total of 753 patients with hyperkalemia (potassium levels 5-6.5 mEq/L), including patients with chronic kidney disease (CKD), heart failure, diabetes, and those on renin angiotensin aldosterone system (RAAS) inhibitor therapy were enrolled in the trial.
In the acute phase of the trial, patients were given one of four doses of ZS-9 (1.25g, 2.5g, 5g or 10g) or placebo, administered three times daily for the initial 48 hours.
The safety and efficacy results of the acute phase demonstrated that the Phase III trial ZS-003 met its primary endpoint and showed a rapid, safe and effective reduction of potassium in hyperkalemic patients within 48 hours, which was the same primary endpoint used in the Phase II trial ZS-002.
Results of both of the clinical studies support the safety and efficacy of ZS-9 in treating hyperkalemia, regardless of underlying cause.
The acute phase was followed by a subacute phase, in which normalised patients were given once-daily doses of ZS-9 (1.25g, 2.5g, 5g or 10g) or placebo for 12 days and its secondary endpoint was the rate of change in serum K+ during the 12-day dosing period.
Denver Nephrology director of clinical research and clinical investigator in the ZS-003 study Geoff Block said: "There is a critical need for a new treatment for patients with hyperkalemia, including those with chronic kidney disease, diabetes, heart failure and those who should be on cardio-renal protective treatment such as ACEs and ARBs."
The company expects to release additional results from the ZS-003 trial, including the subacute phase, in the coming months.
About 90 patients with Stage 3 CKD and mild to moderate hyperkalemia were enrolled in the double-blind, placebo-controlled Phase II trial ZS-002 that assessed the safety and efficacy of ZS-9 in treating hyperkalemia in patients with CKD.
ZS Pharma plans to initiate an additional Phase III study, the ZS-004 trial, in early 2014 under its ZS-9 clinical program which is designed to investigate the treatment of acute, subacute and chronic hyperkalemia.
The ZS-004 study, a randomised, double-blind, placebo-controlled trial, is designed to confirm, using a month-long dosing period, the optimal dose of ZS-9 for extended treatment.