The chief executive of Eli Lilly and Co's Alzheimer's imaging unit is confident it can create a training program for its imaging drug that will satisfy concerns raised by U.S. regulators, according to Reuters. So are many Alzheimer's disease experts, who are gathering in Paris this week for the Alzheimer's Association's international conference. Imaging the clumps of a toxic protein called beta amyloid that accumulate in the brains of patients with Alzheimer's is seen as a critical step toward identifying the disease in the earlier stages, before memory problems begin. Researchers increasingly believe this is the best time to intervene with drugs that might delay or prevent the disease from progressing. Lilly is seeking U.S. Food and Drug Administration approval to market the agent, a radioactive tracer called Amyvid, for use with positron emission tomography, or PET, scans to help doctors rule out the plaque linked with Alzheimer's. In January, an advisory panel to the FDA unanimously said Amyvid appears to detect brain plaques associated with the memory disease, but that more data is needed to show the scans can be properly interpreted. "Since we got that feedback, we're working with the FDA to figure out what is required," said Dr. Daniel Skovronsky, president and CEO of Avid Radiopharmaceuticals, a wholly owned unit of Lilly. "We're quite confident that we will be successful," Skovronsky said in a telephone interview ahead of the conference, which runs July 16-21. He said data from the company's clinical trials was convincing, but the FDA said the test was too complicated for clinical use and may lead to inconsistent readings. So the company is trying to focus its training on answering a simple question: "Is there amyloid in the brain? Yes or no?" Skovronsky said. He said the FDA will not require additional clinical trials involving patients. "I expect ultimately it will win approval," said Dr. Michael Weiner, who is leading the Alzheimer's Disease Neuroimaging Initiative, a federal study that uses imaging and other tests to track the progress of Alzheimer's over time. "I think most people see this as a temporary problem," said Weiner, who also directs the Center for Imaging of Neurodegenerative Disease at the Veterans Affairs Medical Center in San Francisco. If approved, the test will tell doctors whether amyloid is gathering in the brain. If there is none, it would tell doctors to look for other causes of mental decline, such as depression or medications. "I've talked to some scientists who feel these scans can help them in assessing their patients," Weiner said, adding: "Once there are treatments, these tests are going to be much more important." Avid's compound is already being widely used by various drug companies in clinical trials, and Lilly's $800 million acquisition of Avid last November raised concerns among Lilly's rivals. "One of the early questions on everyone's mind was, 'Are you going to continue to collaborate with us even though we are developing a drug that might compete with a Lilly drug?'" "The answer right from the outset was yes," Skovronsky said. "We are committed to this open collaboration model." Avid has been ahead in the race for such imaging agents that are estimated to have a potential global market anywhere from $1 billion to $5 billion. General Electric Co and Bayer AG are also developing rival products, but Avid's delay at the FDA may have cost the company some of its lead. "When you are first, you are developing a path that others will follow. That is the benefit but also the cost of being in the lead," Skovronsky said.