The Alzheimer’s drug trial raises concerns that cognitive decline is accelerating

While a growing body of evidence suggests there is a link between blood iron levels and the development of Alzheimer’s disease, new research examining the effects of an available iron-lowering drug has raised concerns about its use to treat the disease.

As we age, iron deposits in various brain regions can interfere with normal cognitive function. Studies have found that iron plays a role in the development of Alzheimer’s disease, with excessive iron levels contributing to the deposition of beta-amyloid and the formation of tangles in the brain that promote neurodegeneration.

For this reason, drugs that reduce iron overload by binding to iron, a process called chelation, have received widespread attention as potential treatments for Alzheimer’s disease. However, new research examining the effects of a particular iron chelating drug on the progression of Alzheimer’s disease has raised alarm.

The study was a collaboration between Australian institutions including the Florey Institute of Neuroscience and Mental Health (The Florey), the University of Melbourne, the University of New South Wales (UNSW), Monash University, Curtin University and the Queensland Brain Institute Commonwealth Scientific and Industrial Research Organization (CSIRO) and the University of Newcastle.

Researchers studied the drug deferiprone, an iron chelator commonly used to remove excess iron in people with certain blood disorders (thalassemia, sickle cell anemia) who have too much iron in their bodies due to repeated blood transfusions. The 12-month clinical trial was conducted on 81 patients over 54 years of age with mild cognitive impairment or early Alzheimer’s disease and confirmed amyloid deposits. Participants were randomized to receive either 15 mg/kg oral deferiprone twice daily or placebo. The primary outcome was an improvement in cognitive functions – memory, executive function and attention – which researchers assessed at baseline, six and 12 months. Secondary outcomes included a change in iron levels in the brain.

MRIs showed that patients treated with deferiprone had reduced iron levels in the hippocampus, a region of the brain heavily involved in memory, compared to patients in the placebo group. However, while it reduced iron levels in the brain, patients who received the drug experienced accelerated cognitive decline overall, largely due to worsening performance on tests of executive function. Executive function refers to the higher-level mental processes that allow us to make plans, focus our attention, remember, and multitask.

The researchers say their study results suggest that lowering iron levels using deferiprone makes things worse for people with Alzheimer’s.

The study was published in the scientific journal JAMA Neurology.

Source: Scimex