The FDA has accepted for review the resubmission of a new drug application for sodium zirconium cyclosilicate (ZS-9, ZS Pharma/AstraZeneca), a potential new medication for the treatment of patients with hyperkalemia.
In May, AstraZeneca received a complete response letter (CRL) from the FDA with regard to the initial application for sodium zirconium cyclosilicate. The CRL referred to observations arising from a preapproval manufacturing inspection. The FDA also acknowledged the receipt of data that it had yet to review. The CRL did not require the generation of new clinical data.
Sodium zirconium cyclosilicate is an insoluble, nonabsorbed compound with a structure that was designed to preferentially capture potassium ions. The compound has been studied in three double-blind, placebo-controlled trials and in one ongoing 12-month, open-label study in patients with hyperkalemia, representing a treatment population of more than 1,600 patients. Sodium zirconium cyclosilicate is an investigational medication and is not currently approved for any indication in any market.
Hyperkalemia (potassium levels greater than 5.0 mEq/L in blood serum) commonly occurs in patients with advanced chronic kidney disease and/or chronic heart failure, and may lead to cardiac arrest and death. Treatment with commonly used heart medications (i.e., renin–angiotensin–aldosterone system [RAAS] inhibitors) can also be responsible for increases in hyperkalemia. Current therapeutic options are limited.