The U.S. Food and Drug Administration has rejected the new drug application for Amgen’s Parsabiv (etelcalcetide), an investigational treatment for secondary hyperparathyroidism in hemodialysis patients.  The FDA issued a complete response letter to Amgen, and Amgen has not disclosed the details of the letter.

“Amgen is reviewing the complete response letter, and we anticipate a post-action meeting with the FDA later this year to discuss the complete response,” according to a statement from the company. “The Complete Response Letter does not impact our regulatory submissions in other regions.”

Amgen acquired the drug as part of its acquisition of KAI Pharmaceuticals four years ago.

Amgen had said Parsabiv, an intravenous drug, could exceed the revenue of Senspiar, which is taken orally. Clinical trials have suggested that Parsabiv is as good as Sensipar at reducing parathyroid hormones in dialysis patients.