Complete Response Letter for AstraZeneca NDA

FDA has issued AstraZeneca a complete response letter (CRL) for its NDA for ZS-9 (sodium zirconium cyclosilicate), indicated for treating hyperkalemia (high potassium level in the blood serum). The letter identifies observations cited during a pre-approval manufacturing inspection, acknowledging  recently-submitted data which it has yet to review, according to the company. The CRL does not request any new data, it says. 

ZS-9 is an insoluble, non-absorbed zirconium silicate with a three-dimensional crystalline lattice structure that was designed to preferentially trap potassium ions, AstraZeneca says. “The unique potassium selectivity of ZS-9 enables high in-vitro binding capacity for potassium ions even in the presence of other competing ions,” it says. The therapy has been studied in three double-blind, placebo-controlled trials, and in two ongoing 12-month open label studies in over 1,600 patients.