A team of researchers inside Pfizer made a startling find in 2015: The company's blockbuster rheumatoid arthritis therapy Enbrel, a powerful anti-inflammatory drug, appeared to reduce the risk of Alzheimer's disease by 64 percent. The results were from an analysis of hundreds of thousands of insurance claims. Verifying that the drug would actually have that effect in people would require a costly clinical trial - and after several years of internal discussion, Pfizer opted against further investigation and chose not to make the data public, the company confirmed. Researchers in the company's division of inflammation and immunology urged Pfizer to conduct a clinical trial on thousands of patients, which they estimated would cost $80 million ... according to an internal company document obtained by The Washington Post. Pfizer's deliberations, which previously have not been disclosed, offer a rare window into the frustrating search for Alzheimer's treatments inside one of the world's largest drug companies. Pfizer did share the data privately with at least one prominent scientist, but outside researchers contacted by The Post believe Pfizer also should at least have published its data, making the findings broadly available to researchers. Of course they should. Why not?" said Rudolph E. Tanzi, a leading Alzheimer's researcher and professor at Harvard Medical School. "It would benefit the scientific community to have that data out there," said Keenan Walker, an assistant professor of medicine at Johns Hopkins.