Alzheimer's Experts Express Cautious Optimism About New Drug
Here's what to know about aducanumab, and a few others in development
Editor’s note: The Food and Drug Administration approved the first new drug treatment for Alzheimer’s disease in nearly two decades on June 7. Aducanumab is a monoclonal antibody developed by Biogen. Clinical trial results show that the drug reduced the level of amyloid proteins from the brains of trial participants who had Alzheimer’s. The toxic proteins are thought to be a marker of the disease. Aducanumab is intended to slow the cognitive decline that patients experience from Alzheimer’s. However, evidence on whether the drug is effective in helping patients is incomplete. As part of its approval, the FDA is requiring Biogen to conduct another clinical trial to determine the effectiveness of the treatment. In the meantime, aducanumab will be made available as a treatment option for patients with mild memory problems. Biogen has not announced a price for the drug. Wall Street analysts estimate the treatment could cost tens of thousands of dollars per year.
Do people with Alzheimer's disease and their families dare hope that a drug which delays the start of the disease or slows its progression will actually be available soon? Or should they manage expectations — based on 20 years of false starts — when it comes to treatment for this devastating neurogenerative disease?
You may have heard about pharmaceutical company Biogen and its plan to submit a license application for a newly reanalyzed Alzheimer's drug to the Food and Drug Administration (FDA). The company stopped its clinical trial of aducanumab in March because preliminary results did not meet the study goals. However, after analyzing more data, Biogen now says higher doses of the drug, used for a longer time, did reduce symptoms of the disease.
Later-stage clinical trial failure is common among seemingly promising drugs that aim to prevent or slow Alzheimer's. This disease affects 5.8 million people in the United States and nearly 50 million worldwide, according to the Alzheimer's Association and World Health Organization.
Alzheimer's Drugs: Stymied at Phase 3
For the past two decades, Alzheimer's researchers have been stymied when trying to bring new drugs to market. They do well in initial clinical trials, but seem to fizzle out for various reasons by the time the companies are ready to test them in larger, Phase 3 studies.
Phase 3 is when a drug is tested for safety and effectiveness in the patients it's intended to help, according to FDA guidelines. It's the last stage before a drug company can petition the FDA for approval, although more testing also occurs after the drug comes to market.
"You're really deciding at the end of the day, if we were to give this to a population, would it be effective for that population?" says Dr. Joshua Chodosh, a geriatrician and professor in the Department of Population Health at the NYU Langone Health medical center in New York City.
"Alzheimer's is a really awful disease and it affects everybody, not just the person who has it," Chodosh says.
It's also an expensive disease. The Alzheimer's Association estimates that In 2019, Alzheimer's and other dementias will cost the nation $290 billion from increased hospitalizations, home care visits and nursing home admissions. Additionally, family caregivers provide about 18.5 billion hours of unpaid care annually, at a cost of $234 billion.
Enthusiasm and Caution About the Biogen Drug
Cost is among many reasons there's such a desperate effort to halt, or at least slow, progression of Alzheimer's. Biogen's move is being greeted with cautious optimism by Alzheimer's experts.
"It is obviously wonderful for several different reasons that the data is looking promising," says Dr. Andrew Budson, chief of cognitive and behavioral neurology at the Veterans Affairs Boston health care system. "So many of us are touched by this disease; it's such a big problem for our society and the world. The opportunity to have a disease modifying drug, a drug that will actually help to slow down the disease process is just incredibly exciting."
But Budson, also a professor of neurology at Boston University, tempers his enthusiasm, pending additional review of Biogen's data. He says he's still a bit skeptical until he sees more details, and would also like to know what the FDA has to say.
New Life for the Amyloid Hypothesis?
If — and it's a big IF — the drug works, it will be the first new treatment for Alzheimer's symptoms in 16 years. Part of the challenge, says Chodosh, is that like cancer, Alzheimer's isn't just one disease, so it requires precision targeting of what researchers believe to be the mechanism that triggers it: a buildup of amyloid plaque in the brain.
"We have to have hope — that if it's not for us, for our children or grandchildren."
According to Chodosh, Biogen's reanalysis breathes new life into the amyloid hypothesis. "Not only do we see significant reductions in amyloid, it feels like for the very first time in a long time, we may be actually getting somewhere," he says.
However, he cautions that potential side effects are worrisome. About 35% of participants in Biogen's aducanumab study had brain swelling and about 20% had headaches. "That raises some real cause for concern," Chodosh says.
Some of the Biogen trial participants are patients at the Boston Center for Memory, where Budson is medical director. And while he's also concerned about side effects, he thinks that even if the drug only works for some patients, it's still an important scientific finding and shows that researchers are still on the right track.
Another Promising Development
There's also been recent buzz about another promising new drug, called ALZ-801, from Alzheon, a biopharmaceutical company. Company founder Dr. Martin Tolar says the drug is ready for Phase 3 trials.
ALZ-801 works differently than aducanumab. It targets specific toxins called oligomers, which build up in the brain and are believed to lead to plaque formation. Essentially, ALZ-801 prevents formation of the toxin, Tolar says.
"The problem of neurodegeneration is a problem with clearance of toxins from the brain. As we get older, our brains are just not able to clear it out as efficiently," Tolar says, adding that by age 40 or 50, this toxin accumulates and begins to damage the brain. By the time symptoms appear, about 10% of brain function is already lost.
ALZ-801 seems especially effective in patients who have a risk gene called APOE4 . That sub-population, which Tolar says comprises about 65% of all people with Alzheimer's, can be determined through genetic testing. Those with the gene seem to have more of the toxins, and this drug prevents toxins from building up, he says.
"Eventually, the goal is to really treat people with Alzheimer's the same way we treat patients with cardiovascular disease," Tolar says. People could be screened in middle age, before there's major damage from the disease. It's possible that toxic buildup could even be prevented.
ALZ-801 is also easy for patients to take, he says. It's a small tablet, so it can be taken by mouth at home, versus Biogen's aducanumab, which requires intravenous delivery in a clinic or physician's office.
When Could These Drugs Be Available?
But don't go rushing out to your doctor just yet. More studies are needed for both drugs, and however promising they seem today, we won't know for sure until all of the data is collected and analyzed.
If successful, both drugs would be "fast-tracked" through the FDA review and approval process; aducanumab could be on the market within a year or two. And ALZ-801 could launch sometime in 2024, after its Phase 3 study is completed.
That seems a long time to wait for those battling the disease today, and the families who care for them. However, researchers have made tremendous progress in just the last four or five years, building on everything they've learned over two decades, Budson says. He's cautiously optimistic, pending further data review.
"But we have to have hope — that if it's not for us, for our children or grandchildren," he says.
Further adding to the buzz of potentially viable drugs, Green Valley Pharmaceuticals, a Chinese drug manufacturer, received conditional approval in that country to market Oligomannate. "The drug has been found to be capable of treating mild to moderate Alzheimer's disease and can improve cognition," according to the National Medical Products Administration. It is expected to be available in China by the end of 2019.
Oligomannate is derived from seaweed and works on the gut microbe. Chinese scientists say it improved cognitive function in Phase 3 trials in as little as four weeks. However, U.S. researchers are mostly taking a wait-and-see approach, since the studies have only lasted nine months and data has not yet been made publicly available.
"I'm more optimistic than I was three weeks ago," Chodosh said. He says the news from China will likely spur other kinds of research questions and investigations that could benefit research on Alzheimer's treatments. "This is in no way the absolute answer. But it's a start," he says.
