"A proposed decision is forthcoming after CMS has reviewed newly published evidence," the CMS said, in a statement posted December 15.

The CMS was expected to announce a proposal by December 16 to change its coverage of amyloid PET scans for individuals in Alzheimer's disease clinical trials. Currently, participants are limited to a single scan per lifetime, and the CMS decision could have a major impact on how patients are managed and how new treatments are evaluated.