Leon J. Thal, MD, 62, renowned worldwide as an authority in the development of new therapies for Alzheimer disease (AD), often liked to fly his small plane solo. But on Feb. 3, he met an untimely death when he was killed in a plane crash near Borrego Springs, CA. He had taken off from San Diego around 6:30 pm that night and a distress signal was detected around 10 pm. The plane, with only Dr. Thal on board, crashed under unknown circumstances.
Dr. Thal was distinguished professor and chair of neurosciences at the University of California-San Diego (UCSD) School of Medicine since 1993, the Florence Riford Endowed Chair in Alzheimer's Disease at UCSD, and the director and primary investigator of the UCSD Shiley-Marcos Alzheimer's Disease Research Center. He was on staff at the Veterans Affairs San Diego Healthcare System, where for several years he was chief of neurology, and also served as director of the multi-center Alzheimer's Disease Cooperative Study since its establishment in 1991.
The Alzheimer disease community and his colleagues at UCSD reacted with shock and sorrow to the news. “Upon reflection, the mind boggles at the number oftop-tier operations for which Leon Thal was the linchpin, any one of which is a daunting task.There was no one who played more than Leon the role of ‘glue,’ holdingtogether the Alzheimer disease academic clinical trial operation in this country,” said Sam Gandy, MD, PhD, chair of the National Medical and Scientific Advisory Board of the Alzheimer's Association and director of the Center for Neurodegenerative Disease at Emory University in Atlanta, GA. “I wonder how many people it will take to fill the void he leaves.”
“Dr. Thal was a remarkably successful department chair and academic leader,” said Henry C. Powell, MD, professor of pathology and chair of the UCSD Academic Senate. “He was also a truly nice, likeable person who showed great skill in managing a large and complex department as well as a research operation of considerable size. Few could understand how he kept it all going, but he did so and remained cheerful and optimistic and, of course, continually successful.”
Dr. Thal trained in neurology at the Albert Einstein College of Medicine in the Bronx, and was named an assistant professor of neurology there in 1977. He practiced in the Bronx at Bronx Municipal, Lincoln, and St. Barnabas Hospitals in the 1970s and 1980s, but moved to the University of California-San Diego in 1985, when he became an associate professor of neurosciences. He was appointed a professor of neurosciences in 1989.
Dr. Thal's major research interests included behavioral studies of dementia, clinical trials and biomarkers in Alzheimer disease, enhancement of neuronal function and regeneration, and genetics.
In the 1970s, he began aggressively pursuing the cholinergic hypothesis of Alzheimer disease in animal and clinical studies. He subsequently performed clinical trials using choline, lecithin, and other precursors of acetylcholine. In 1983, he reported in the New England Journal of Medicine the first evidence that memory could be enhanced in Alzheimer patients with cholinesterase inhibition.
“He was our best advocate for obtaining research support for Alzheimer disease research and was a most effective catalyst in moving forward the clinical research agenda to bring effective therapies to our patients,” said Roger N. Rosenberg, MD, Zale Distinguished Chair and professor of neurology, and director of the Alzheimer's Disease Center at the University of Texas Southwestern Medical Center at Dallas.
“Dr. Thal was the major figure in clinical trials in AD research,” said close friend and colleague Ronald C. Petersen, PhD, MD, professor of neurology, Cora Kanow Professor of Alzheimer's Disease Research, and director of the Alzheimer's Disease Research Center at the Mayo Clinic College of Medicine in Rochester, MN. Dr. Petersen, who collaborated with Dr. Thal on many major research projects since the mid-1980s, noted that Dr. Thal was the ultimate moderator, a sought-after, well-respected scientist and clinician marveled at for his energy, commitment, compassion, and sense of humor.
“His passion was to solve the problem; he had a genuine devotion to find treatments for Alzheimer disease and to make lives better for patients and their families.”
As the director of the Alzheimer's Disease Cooperative Study, Dr. Thal spearheaded an association of more than 70 research centers in the United States and Canada that tests drugs for their efficacy in slowing the progression of AD or treating its symptoms. The consortium, which also investigates new methods for conducting dementia research, was recently awarded $52 million by the National Institute on Aging (NIA) to conduct new clinical trials on Alzheimer disease.
Two months ago, Dr. Thal was named to the Alzheimer's Association's National Board of Directors, where he had served as a member of the association's Medical and Scientific Advisory Board from 1995 to 1997 and had been on the San Diego chapter's Board for 10 years.
Dr. Thal served as a scientific advisor for the UC Irvine and Boston University Alzheimer's Centers, as well as the Lou Ruvo Brain Institute in Las Vegas, NV, and also served on the National Institute on Aging Advisory Council. The author of more than 300 peer-reviewed papers, he was an editorial and journal reviewer for Neurobiology of Aging, Alzheimer's Disease Review, the Journal of Neural Transmission, and associate editor of Alzheimer's and Dementia. In 2004, the AAN awarded Dr. Thal the Potamkin Prize, one of the nation's chief honors in neurosciences, for his contributions to AD research.
“We have lost one of the giants at UCSD and in the world of Alzheimer's disease research,” Patrick Lyden, MD, vice-chair of the UCSD department of neurosciences and chair of the School of Medicine Faculty Council, told Neurology Today. “He led the UCSD department of neurosciences for over a decade, during which time our department grew exponentially. Our neuroscience graduate training program has been rated number one in the country. Personally, Dr. Thal mentored all of us with humor and candor…For me, I have lost a leader, mentor and friend who simply cannot be replaced.”
Dr. Thal is survived by his wife, Donna Thal, PhD, a neuropsychologist and professor emeritus at San Diego State University.