FDA rejects AstraZeneca hyperkalemia drug, boosting competitor Relypsa
- In a major setback, AstraZeneca said the FDA rejected its application for approval of an investigational hyperkalemia drug which it acquired last year in a $2.7 billion deal for ZS Pharma.
- The FDA issued a complete response letter (CRL) to the drugmaker over issues found in a pre-approval manufacturing inspection. AstraZeneca said the FDA would not require new clinical data for the drug, known as ZS-9.
- While AstraZeneca said it would work with the FDA to decide on next steps for resubmission, the CRL will likely delay another decision on the drug to sometime next year, notes Reuters.
ZS Pharma and its hyperkalemia drug were a hot commodity last year. AstraZeneca narrowly beat out Actelion Pharma with its bid and predicted ZS-9 could reach $1 billion in annual sales at peak.
AstraZeneca expected ZS-9 to offer stiff competition to Relypsa, which already sells its own hyperkalemia drug Veltassa. Those plans will now have to be delayed, giving Relypsa more time to establish market share for Veltassa.
This is important because when Veltassa was approved, the FDA required the drug to carry a black-box warning due to the risk it would bind to other medications, thereby decreasing absorption. The warning would have been a competitive disadvantage if ZS-9 had been cleanly approved.
Shares of Relypsa surged over 15% in early trading Friday, while Astrazenca stock dipped slightly.
If there is a silver lining to the rejection, the FDA will not require costly and potentially lengthy clinical trials as a requirement for re-evaluation. AstraZeneca also said the FDA had "acknowledged receipt of recently-submitted data which it has yet to review."
According to comments from the company cited by FierceBiotech, the submission included manufacturing data rather than clinical trial data.
Hyperkalemia, or high potassium levels in the blood, typically occurs in patients with chronic kidney disease or heart-failure. Mortality rates in patients with severe hyperkalemia are as high as 30%, according to AstraZeneca.
AstraZeneca said it "remains committed" to ZS-9's development, and is in discussion with regulators in Europe and Australia, where ZS-9 is also under review.
Follow Ned Pagliarulo on Twitter