AstraZeneca still frustrated over ZS hyperkalaemia drug

The US Food and Drug Administration (FDA) has issued a complete response letter to AstraZeneca regarding its new hyperkalaemia drug, meaning its application still cannot be approved in its present form.

Following the issue of the letter, the FDA has inspected the manufacturing facility of the sodium zirconium cyclosilicate (ZS-9) drug at ZS Pharma, the company’s subsidiary which is developing the drug.

Hyperkalemia – high potassium levels in the blood serum – commonly occurs in patients with advanced chronic kidney disease and/or chronic heart failure, and may lead to cardiac arrest and death.

The complete response letter does not require any new clinical data and AstraZeneca said that it and ZS Pharma were committed to working with the FDA to resolve the remaining matters under review as soon as possible.

In May last year the drug’s US approval was rejected by the FDA over manufacturing concerns, which was a blow to the pharmaceutical giant, as it had bought ZS Pharma for $2.7bn in 2015 in order to get access to ZS-9.

In February, ZS-9 received “positive opinion” by the Committee for Medicinal Products for Human Use in the European Union and should get regulatory approval in the coming months.

The delay in US approval has put AstraZeneca on the back foot against rival Relypsa, which already makes a drug that treats hyperkalemia called Veltassa.