U.S. health reviewers' main concern with Eli Lilly & Co's imaging agent for Alzheimer's tests is whether technicians can properly read the scans and how useful they are in assessing the degenerative disease.
The radioactive dye, called florbetapir F 18, is intended for use with positron emission tomography, or PET, scans that help detect the presence of beta-amyloid plaques linked to Alzheimer's disease.
The Food and Drug Administration staff reviewers' main concerns "relate to an apparent insufficient development of the reader training methods proposed for clinical use," according to documents released on Tuesday ahead of a public meeting on Thursday to consider approval.
But at least one reviewer also cited the high variability in reading the scans and the study's small sample size. "No clear clinical utility is demonstrated" in the company's clinical trial, the reviewer added.
At the meeting on Thursday, an FDA panel of outside experts will weigh the FDA staff's assessment along with company data before offering the agency its recommendation on whether to approve the drug.
Lilly obtained the drug, also known by its proposed brand name Amyvid, through its recent acquisition of Avid Radiopharmaceuticals Inc.
Other companies, including General Electric Co and Bayer AG, are developing rival products.