Avid Radiopharmaceuticals Inc. will be bought by Eli Lilly & Co. in a deal valued at up to $800 million.

Shareholders in the privately held West Philadelphia life-sciences firm would get $300 million in cash at closing and up to an additional $500 million depending on the various milestones reached by its Alzheimer's disease diagnostic compound.

The transaction should come as no surprise because Lilly's venture capital arm has had a stake in Avid since early 2006.

In April, Avid reported positive interim results from a Phase III clinical trial of its florbetapir imaging agent, which is designed to image beta-amyloid in living patients suspected of having Alzheimer's disease.

Unsaid in the news release is what might happen with its offices at the University City Science Center.

Avid has been working on new imaging compounds to aid in the detection, diagnosis and monitoring of various chronic diseases.

One of its shareholders is Safeguard Scientifics Inc., which estimates that it will net $36 million, or three times its investment in Avid, once Lilly close the deal.