Alzheimer's treatments: What's on the horizon?

Despite many promising leads, new treatments for Alzheimer's are slow to emerge. Future treatments will likely focus on stopping the disease in people at risk.

Alzheimer's treatments consist mainly of medications that stabilize cognitive function, if only for a short period of time. These drugs stage a holding action, primarily postponing further cognitive declines.

But the Alzheimer's treatments of the future will focus more on preventing the disease or halting its progress in its earliest stages. The following treatment options are among the strategies currently being studied.

Alzheimer's vaccine

Immunization can reduce the number of amyloid plaques — clusters of abnormal cells associated with Alzheimer's disease — in the brain. But a human trial of an Alzheimer's vaccine was halted when several participants developed brain inflammation.

A follow-up study indicated that people who received the Alzheimer's vaccine tended to have far fewer amyloid plaques in their brains than did people who hadn't been immunized. But this didn't appear to affect the end result. The immunized participants progressed to severe dementia and died at the same rate as that of people who hadn't received the vaccine.

Some scientists believe that amyloid's harmful effects may occur before it clumps up into plaques. Researchers are investigating other forms of vaccination that may be more effective and less dangerous.

Secretase modulators

Amyloid plaques are formed from fragments of a large protein believed to be important in brain function. Secretase enzymes divide this protein into fragments. Some secretase enzymes create fragments that tend to clump into amyloid plaques, while another secretase enzyme produces fragments that don't tend to clump.

Secretase-modifying drugs might block the action of the clumping enzymes, or activate the nonclumping enzyme.

Certain anti-inflammatory drugs — including ibuprofen (Advil, Motrin, others), naproxen sodium (Aleve) and indomethacin (Indocin) — appear to modify how one of these enzymes works, so that it doesn't produce fragments that clump. One of the most promising drugs being studied in this group is tarenflurbil (Flurizan).

Antibiotics

A three-month course of antibiotics, specifically doxycycline and rifampin, reduced the rate at which cognitive problems worsened in a group of people who had mild to moderate Alzheimer's disease. The antibiotics appear to interfere with the development of amyloid plaques in the brain.

Hormones

Early studies indicated that hormone replacement therapy, typically prescribed to ease menopausal symptoms, might protect women over the age of 65 against Alzheimer's. But more recent studies not only refute these findings but also suggest that this hormone therapy might even increase the risk of dementia.

The timing of the hormone replacement therapy may be the reason for apparently contradictory results. Some researchers speculate that early hormone therapy, during a woman's 50s, may be protective, while later use becomes harmful.

In men, low testosterone levels have been linked to increased risk of Alzheimer's disease. Researchers are investigating whether testosterone supplements might help men who have Alzheimer's or are at risk of the disease, but the results have been mixed.

Timeline for answers

New Alzheimer's treatments take time to develop, and then even more studies are needed to establish a treatment's safety and effectiveness. But all this time and effort will eventually pay off. Most researchers expect to see major progress in the treatment and prevention of Alzheimer's in the next few decades.