A large German study is the latest clinical trial to suggest that a cheap generic treatment for diabetes can stave off symptoms of Alzheimer's disease, although conclusive proof from a more formal trial could be about five years away.
Earlier studies have suggested that people and animals given the widely used pill for type-2 diabetes, called pioglitazone, were less likely to develop Alzheimer's or other forms of dementia. The medicine is sold under the brand name Actos by Japanese drugmaker Takeda Pharmaceutical Co Ltd.
Researchers in the new trial used routine data from German healthcare plans for the years 2004 until 2010. They tracked a database of about 146,000 patients age 60 and older who initially did not have evidence of dementia.
The analysis showed that 13,841 subjects eventually developed dementia, and that for those taking pioglitazone the risk of dementia was significantly reduced with each additional three months the drug was prescribed.
"The long-term use of pioglitazone reduces the risk of dementia incidence," based on examination of health claims data, concluded Anne Fink, a researcher for the German Center for Neurodegenerative Diseases who helped lead the trial. Her data was presented Monday at the annual meeting of the Alzheimer's Association International Conference in Copenhagen.
Fink speculated that pioglitazone helped prevent Alzheimer's by reducing inflammation in the brain and nervous system, although other effects of the drug might also be at play.
Separate earlier studies of patients with type 2 diabetes have found that those with poor blood sugar control are much more likely to develop dementia. Moreover, those taking medicines like Actos - called thiazolidinediones (TZDs) - have been shown to be at almost 20 percent less risk of Alzheimer's than those who took insulin.
Takeda last year began a five-year study, in collaboration with privately held Zinfandel Pharmaceuticals Inc, to assess whether low doses of pioglitazone can delay the onset of mild cognitive impairment due to Alzheimer's disease. Using a special diagnostic test, the trial will enroll cognitively normal people who have genetic variations known to increase the risk of early onset of Alzheimer's symptoms.
Stephen Brannan, in charge of central nervous system drug development at Takeda, speculated that pioglitazone may help arrest Alzheimer's by improving the function of mitochondria: energy-producing compartments in every cell of the body except red blood cells.
"The brain requires a lot of energy," he said in an interview, adding that more efficient mitochondria could improve brain function and thereby help stave off Alzheimer's.
Some 18 million Americans suffer from Alzheimer's, according to Takeda, with the rate of occurrence doubling every five years for those between 65 and 85 years of age.