Dale Schenk, the co-founder and chief executive officer at Prothena Corp. who devoted his scientific career to researching neurological diseases such as Alzheimer’s and Parkinson’s, has died. He was 59. He died Sept. 30 at his home in Hillsborough, California, Ellen Rose, a spokeswoman for Prothena, said in a telephone interview. The cause was pancreatic cancer, according to a statement from the Dublin-based biotechnology company. He was diagnosed with the disease in December 2014 and announced on Sept. 26 that he was taking a medical leave of absence. Schenk gained prominence in the early 2000s for his work at Elan Corp., where he helped devise a vaccine to target beta amyloid, the protein that builds up in the brains of patients with Alzheimer’s disease. Schenk climbed the ranks at Elan, rising to chief scientific officer and executive vice president after landing at the company through its acquisition of Athena Neurosciences in 1996. He left to help co-found and lead Prothena in 2012, after the development of bapineuzumab was halted after a second failed trial. Prothena grew to have a market valuation of $2.06 billion. He received a bachelor’s degree in biology from the University of California at San Diego in 1979, according to his LinkedIn.com profile. In 1984, he earned a Ph.D. in physiology and pharmacology from the school. After gaining his doctorate, Schenk became a staff scientist at Scios Inc. of Mountain View, California. In 1987, he joined Athena Neurosciences Inc., in San Francisco, where he was director of neurobiology. He stayed on when the company was acquired by Elan in 1996, and was named chief scientific officer in 2008. He became head of Elan’s Neotope Biosciences division in 2009. Schenk is survived by his wife, Elizabeth, and their children Max and Sam, and two children, Anais and Sara, from a previous marriage to Maria Torres, who died in 2005.