Experimental drugs that clear clumps of proteins from the brains of Alzheimer’s patients haven’t panned out yet.
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An experimental drug dramatically reduced the toxic plaques found in the brains of patients with Alzheimer’s disease, a team reports in the journal Nature.
Results from a small number of patients who received a high dose of the drug, calledaducanumab, hint that it may also be able to slow the loss of memory and thinking.
“If that hint of a clinical benefit is confirmed, it would be a game changer in the fight against Alzheimer’s disease,” says Dr. Eric Reiman, executive director of the Banner Alzheimer’s Institute in Phoenix. Reiman wrote a commentary that accompanies the study in Nature.
But it will take much larger studies to show for sure whether aducanumab really does slow down Alzheimer’s disease, Reiman says.
Officials of Biogen, which is developing the drug, were also cautious about interpreting the results of the study, which included 165 patients in the early stages of Alzheimer’s disease.
“We think we have something important here,” says Dr. Alfred Sandrock, chief medical officer for Biogen. “We hope we’re right because if it’s true it would benefit millions of patients. But we don’t know we’re right yet.”
The results are encouraging for pharmaceutical companies that have spent billions of dollars on efforts to come up with the first drug to treat the underlying cause of Alzheimer’s. Those efforts have failed to produce a single approved drug so far.
But last summer, Biogen began presenting its results with aducanumab at scientific meetings, including the Alzheimer’s Association International Conference in July. These early reports suggested the drug had a remarkable ability to remove plaques in the brain.
“It was surprising, encouraging and thought-provoking to see such a striking reduction of existing plaques,” Reiman says.
The publication in Nature Wednesday provides details about those early reports.
Biogen has already begun two much larger studies of aducanumab. They will include a total of 2,700 patients, and results are still several years off.
But there are reasons to think aducanumab may succeed where other drugs have failed.
One is that the drug appears to ignore benign forms of amyloid protein while attacking the toxic forms thought to damage brain cells. Another is that aducanumab seems to enhance the ability of existing immune cells in the brain to devour toxins, including amyloid.
But there’s a downside. The process of removing plaque sometimes causes fluid to build up in the brain. In rare cases, it can also cause bleeding. These side effects are known as amyloid-related imaging abnormalities, or ARIA.
“We were actually anticipating that we would see it,” Sandrock says. And the researchers did. Twenty patients dropped out of the trial because of adverse effects.
If aducanumab works in larger studies, it could help settle a long-running debate about whether amyloid is really the root cause of Alzheimer’s. This idea is known as the amyloid hypothesis.
And large studies showing that removing amyloid can preserve memory and thinking “would go a long way toward validating the amyloid hypothesis,” Sandrock says.
Results like those could also lead to the first approved drug to treat the underlying cause of Alzheimer’s rather than just the symptoms.
This NPR story discusses early studies on an experimental amyloid-reducing drug that researchers hope may prevent Alzheimer’s disease. It does a good job of balancing the promise of the drug with realistic assessments about the early stage of the research and the fact that there are potential downsides to this treatment.
Importantly, and in contrast to many stories we’ve seen that report on experimental Alzheimer’s drugs, the story doesn’t equate amyloid reduction with reduced risk of disease. It acknowledges that we don’t know whether amyloid is actually the cause of the Alzheimer’s or a by-product of some process that begins elsewhere. That’s important context. Still, the story would’ve been better with a more precise description of the benefits seen in early studies and with perspective from a truly independent source. It also should have explained why some of these same results, reported last year, were generally greeted with disappointment.
That being said, we were glad to see that this story avoided the hype that so many other outlets chose to stoke with headlines like these:
Many stories suggest that reducing amyloid deposits in the brain is the same thing as reducing Alzheimer’s risk. But that’s never been proven, and some studies suggest that reducing amyloid may not have any effect on the disease symptoms that people care about. It’s important to explain this uncertainty to readers. Journalists shouldn’t suggest that a drug is a home run when it’s still standing on second base. This story took a measured approach that we wish we saw more often.
The story doesn’t mention costs. However, the piece is clear that this is early-stage research that might not pan out, so we think it’s acceptable that there’s no cost discussion.
The story suggests that treatment with aducanumab results in “striking,” “dramatic” and “remarkable” reductions in amyloid plaques in the brain. But it doesn’t quantify what that means. How many patients saw their plaque levels go down? By how much? Is the reduction bigger than what has been seen with other experimental Alzheimer’s drugs? These details would’ve been helpful.
The story is clear that the drug’s effects on amyloid plaque are accompanied by potential harms:
But there’s a downside. The process of removing plaque sometimes causes fluid to build up in the brain. In rare cases, it can also cause bleeding. These side effects are known as amyloid-related imaging abnormalities, or ARIA.
We’re also told that about 20 participants dropped out of because of adverse effects.
The story cautions that these results are from small, early studies and that plaque reduction is a proxy for outcomes that really matter to patients.
But it will take much larger studies to show for sure whether aducanumab really does slow down Alzheimer’s disease, Reiman says.
And unlike many stories we’ve seen that discuss therapies to reduce amyloid, this piece acknowledges that we don’t whether amyloid is actually a cause of Alzheimer’s symptoms or perhaps an effect of the disease.
If aducanumab works in larger studies, it could help settle a long-running debate about whether amyloid is really the root cause of Alzheimer’s. This idea is known as the amyloid hypothesis.
And large studies showing that removing amyloid can preserve memory and thinking “would go a long way toward validating the amyloid hypothesis,” Sandrock says.
We do wish the story had noted that about one third of patients in all groups dropped out before completion of the study, which could impact the quality of the overall findings.
The story doesn’t disease monger, but it also doesn’t explain what Alzheimer’s is or give any sense as to the impact of the disease. We’ll rate this Not Applicable.
The story quotes an official from Biogen (which makes the experimental drug) and the author of an accompanying editorial. But we don’t hear from any truly independent sources in the story. The editorialist, Dr. Eric Reiman, is said to be the executive director of the Banner Alzheimer’s Institute in Phoenix. It doesn’t explain that the Banner Institute is leading Alzheimer’s Prevention Initiative, an effort to postpone and prevent the disease before it starts. The initiative partners with a number of drug companies, including Roche, Amgen, Genentech, Novartis, on its studies. These relationships merited a mention in the story.
The story is clear that there are no drugs that treat the underlying cause of Alzheimer’s. It links to a story about a competing amyloid-reducing drug that failed to produce any benefit in a large clinical trial.
We did want to know: Are there any older drugs that have been tried for this? Were they equally optimistic when they were first introduced? Putting them into perspective would help as it seems there were prior drugs that were hyped to prevent or slow the progression of AD–but subsequently didn’t pan out.
The story calls the drug experimental and says that it will take several years for larger studies to report results. It’s apparent that the drug won’t be available outside of a research study any time soon.
The story establishes what appears to be novel about this drug compared with others that reduce amyloid plaques.
One is that the drug appears to ignore benign forms of amyloid protein while attacking the toxic forms thought to damage brain cells. Another is that aducanumab seems to enhance the ability of existing immune cells in the brain to devour toxins, including amyloid.
But while the story is clear that the new paper is presenting details of research first reported last year, it doesn’t explain why the results are now “remarkable” whereas last year they were considered “disappointing,” “mixed” and a “setback.”
We’ll rate this a borderline Satisfactory.
The story includes original reporting and clearly goes beyond any news release.
Systematic, Criteria-Driven
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