Amgen says FDA wants more data on Prolia as a bone loss treatment, delaying potential approval

FDA letter delays OK for Amgen bone drug Prolia

THOUSAND OAKS, Calif. — Amgen says the Food and Drug Administration wants more information about its osteoporosis treatment Prolia before granting marketing approval. It delays a drug seen as a potential blockbuster for the company.

In a letter, the FDA said it wants to know how Amgen will monitor patients who use the drug, and wants the company to develop a strategy to evaluate the risks of Prolia, Amgen said. Amgen shares fell 3 percent in premarket trading.

The company wants to market Prolia for the prevention and treatment of postmenopausal osteoporosis. The FDA said Amgen needs to run more clinical tests of Prolia as a preventive therapy.

The Thousand Oaks, Calif.-based company expects a separate response to its application for Prolia as a treatment for bone loss caused by hormone deprivation therapy.