Asthma drugs, cancer drugs, even obesity drugs, are all being explored for their potential in treating the pathology and symptoms of Alzheimer’s disease. Finding the right one would be doubly good news: A drug already approved for another illness could save decades and millions of dollars in research and development.

Could a drug that’s already sitting on pharmacy shelves secretly hold the power to treat Alzheimer’s disease? Drug researchers say that a number of drugs already approved for other medical conditions might turn out to be effective treatments for this rampant and fatal neurological disease. It’s an exciting prospect, as repurposing drugs is a fast, cost-effective strategy to make a new treatment available to patients. So, they are testing the most promising of these drugs in clinical trials to see if they help reverse the signs and symptoms of Alzheimer’s.

If a drug is found to make a positive difference for someone living with Alzheimer’s, it might lead to the development of entirely new kinds of Alzheimer’s treatments as well. For example, a new diabetes and obesity drug called Wegovy (generic name semaglutide) doesn’t target amyloid plaques like the two disease-modifying Alzheimer’s drugs currently on the market. Instead, preliminary studies of Wegovy show it may reduce the risk of developing dementia or Alzheimer’s in people with risk factors like Type 2 diabetes by changing the brain’s metabolism.

Repurposing drugs that target the brain’s metabolism

In Alzheimer’s the brain can’t turn glucose into energy efficiently. This causes downstream effects impacting the immune system, plaque formation, and cognitive function.

Wegovy is a new drug that treats two major risk factors of Alzheimer’s: diabetes and obesity. Drugmaker Novo Nordisk is testing whether it prevents Alzheimer’s as well by boosting brain metabolism.

An early study conducted by researchers funded by Novo Nordisk looked at data across 130,000 people with Type 2 diabetes taking Wegovy and similar drugs, finding that it reduced the risk of developing dementia by 50 percent. Similar drugs like liraglutide are being tested for early Alzheimer’s as well. It may take two more years for these clinical trials to provide a definitive answer.

Repurposing drugs that target the brain’s immune system

This discovery didn’t come out of the blue: A previous study from 2021 determined that existing drugs targeting the immune system are a promising target for Alzheimer’s. Given everything scientists know about the immune system, this makes a lot of sense.

The brain’s immune cells — microglia and astrocytes — protect the brain by processing waste, responding to infections, and supporting the other cells. When something goes wrong, it could lead to a buildup of plaques and cell death.

Several drugs that affect the immune system are being tested in Alzheimer’s trials. Early studies suggest anti-cancer medications like sargramostim and nilotinib could work, but larger studies are needed.

Repurposing psychiatric drugs for Alzheimer’s

Scientists aren’t just looking at existing medications for physical ailments. There are strong links between mental health conditions and Alzheimer’s, so drugs that treat neuropsychiatric conditions are under the microscope, too. Depression, for example, shares many symptoms and is a major risk factor for Alzheimer’s, and one study found that the antidepressant imipramine and the antipsychotic olanzapine could be potential treatments for people with the Alzheimer’s gene, APOE4. Another study suggested that treating conditions like depression early could prevent dementia.

Approved drugs for asthma, arthritis, attention-deficit hyperactivity disorder (ADHD), high blood pressure, epilepsy, Herpes virus, insomnia, malaria, and hormone replacement therapy are also being tested now.

The World Health Organization expects more than 150 million people will develop dementia by 2050. Repurposing drugs is a fast and cost-effective strategy to develop more new treatments.

To learn about clinical trials of new medications that aim to modify the pathology of Alzheimer’s disease, call Charter Research at 407-337-1000 (Orlando) or 352-775-1000 (The Villages).