Drug May Slow Memory Loss in Early Alzheimer's
Medication Approved to Treat Patients With HIV May Do Double Duty for Dementia
Aug. 6, 2012 -- A drug that's already been approved by the FDA for use in HIV patients may also help slow the decline of memory and mental function experienced by people who are in the early stages of Alzheimer's disease.
The drug, Egrifta, stimulates the release of human growth hormone from the brain's pituitary gland. It was approved by the FDA in 2010 to help correct the abnormal distribution of body fat that often occurs in patients who live with HIV.
A new study published in the Archives of Neurology suggests it may also slow memory loss in people who have mild cognitive impairment (MCI), a condition that often precedes full-blown Alzheimer's disease.
For the study, researchers assigned adults between the ages of 55 and 87 to get either nightly injections of Egrifta or a placebo for five months. Some were healthy and showed no evidence of memory problems on a battery of mental function tests. Others showed MCI, or memory loss that was worse than expected for their age but was not yet severe enough to interfere with daily living.
A total of 137 patients -- 76 who were healthy and 61 with MCI -- finished the study. Researchers brought them back to the lab four times: at the start of the study, then at weeks 10, 20, and then another 10 weeks after the nightly shots stopped.
At each visit, their blood was drawn. In addition, they took a battery of tests that measured different skills used in mental processing and short-term recall of words, shapes, and facts. Researchers also asked them about their mood and sleeping patterns.
In both healthy adults and those with MCI, those taking Egrifta fared better than their counterparts who took placebo injections.
Healthy adults saw their executive function improve by about 200% over their peers who got a placebo. Executive function refers to the brain's ability to manage attention and concentration, to switch between thoughts, and use working memory to plan and strategize tasks.
Adults with MCI still saw their executive function slip over the five months of the study, but their declines were not as large as those in the placebo group.
"Their expected decline was cut in half," says researcher Laura D. Baker, PhD, a psychiatrist at the University of Washington School of Medicine in Seattle.
By the end of the study, people on the drug were also better able to recall words and details of stories a bit better than people on the placebo, though the differences between the groups were not significant.
How Egrifta Works
Egrifta is a close copy of a chemical that's already made by the body called growth-hormone-releasing hormone. As the name implies, it stimulates the production of human growth hormone (HGH). Human growth hormone, in turn, triggers the release of a whole cascade of other hormones including insulin and its close cousin, insulin-like growth factor.