FDA rejects Lilly imaging agent

The US Food and Drug Administration (FDA) has informed Lilly and its recently acquired subsidiary Avid Radiopharmaceuticals that it cannot approve the company's current new drug application for Amyvid (florbetapir F 18 injection), an imaging agent intended to help rule out Alzheimer's disease in patients with cognitive decline.

Amyvid is designed to detect beta-amyloid plaque in the brains of living patients using positron emission tomography – a technique to use small amounts of radioactive material to create a three-dimensional image of functional processes in the body. Lilly acquired the product when it bought Avid late last year. Amyvid, which was recently assigned a priority review by the FDA, is Avid's lead candidate.

"The complete response was primarily focused on the need to establish a reader training programme for market implementation that helps to ensure reader accuracy and consistency of interpretations of existing Amyvid scans," according to Lilly.

The company said that Avid has been engaged in an ongoing dialogue with the FDA about the issue since questions about the reader training programme were originally raised by FDA reviewers late last year.

In January, the FDA's Peripheral and Central Nervous System Drugs Advisory Committee voted 13 to three to recommend that the FDA decline to approve the application in its current form. However, the 16-member panel voted unanimously to recommend approval of Amyvid "conditional on a reader training programme that demonstrates reader accuracy and consistency through a re-read of previously acquired scans."

The advisory panel members' concerns echoed issues raised by FDA staffers in documents prepared in advance of the meeting that questioned whether technicians could accurately read the scans produced using Amyvid. Questions have also been raised by advisory committee members and FDA staffers about the usefulness of a diagnostic tool such as Amyvid even if it is accurate, given that there is no currently approved cure for Alzheimer's disease.

Amyvid has thus far been studied in more than a dozen trials enrolling 700 subjects ranging from cognitively normal individuals to those with Alzheimer's dementia, according to Lilly.