There are about 30 drugs for Alzheimer's disease now in Phase III clinical trials—the last set of experiments drug companies must run to prove their product is safe and effective before obtaining Food and Drug Administration approval.
But don't be fooled by press releases like this one, touting "27 Phase III ... Alzheimer's drugs on track to launch in the next five years." Judging from past Alzheimer's drugs' success, it's unlikely many—if any—of these medicines will make it to market. In 2014, researchers found that, out of 244 Alzheimer's treatments that were deemed promising enough to test in clinical trials between 2002 and 2012, only one made it to market. That's a failure rate of 99.6 percent. In contrast, the general failure rate for pharmaceuticals as a whole is an estimated 89.6 percent.
"The pipeline for Alzheimer's disease is pretty poor," says Aaron Ritter, a doctor at the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, and a member of a team that surveyed developing Alzheimer's drugs in 2016 and 2017. The team's latest survey was published in the September issue of the journal Alzheimer's & Dementia.
"If we think that 99 percent of those is going to fail, that doesn't give us much of a chance to reach our goal of finding some meaningful treatment by 2025," Ritter says.
"The pipeline for Alzheimer's disease is pretty poor."
The 2025 date comes from both the National Plan to Address Alzheimer's Disease, which officials originally published in 2012, and a 2013 meeting of the G8 countries about dementias, which include Alzheimer's as well as other memory-loss conditions. Why 2025? "A lot of the epidemiology work says that, if we don't find better cures by 2025, that, in 2050, the health economies are not going to be able to handle the number of people living with Alzheimer's disease," Ritter says. One study, based on 2010 numbers, estimated that 13.8 million Americans will have Alzheimer's dementia by 2050 if no better therapies are found. Dementias may cost America more than $1 trillion by 2050, the Alzheimer's Association estimates.
The United States' National Alzheimer's Project Act of 2011 helped speed the search for treatments somewhat by funneling federal money into research and encouraging scientists to collaborate and share data, Ritter thinks. Still, it doesn't seem to be enough.
Ritter and his team hope to publish surveys on Alzheimer's drugs every year, to help other scientists identify gaps in the science. In the researchers' papers, they identify why they think Alzheimer's cures are so hard to find. Speaking to Pacific Standard, Ritter mentions a few related reasons. Alzheimer's disease is difficult to study because it develops over many years, he says; from a pharmaceutical company's point of view, that means longer-lasting, more expensive clinical trials than for the typical drug. In addition, many medical mysteries remain about what, exactly, causes Alzheimer's symptoms and what anti-Alzheimer's drugs should target in the brain. "So if you take that idea to an investor, there's not a lot of people that are willing to jump in and get involved," Ritter says.
Ritter and others propose finding new ways to fund Alzheimer's research, perhaps by combining money from governments and drug companies. And what can folks at home do to support the search for a cure? Ritter suggests volunteering for clinical trials about Alzheimer's disease and voting for politicians who support funding biomedical research.