Biogen and Eisai’s new Alzheimer’s drug is just the start

A drug developed by Biogen Inc. and Eisai Co. achieved a first in Alzheimer’s disease research: in a large late-stage trial, lecanemab slowed cognitive decline in people with early-stage disease .

The effect of therapy was modest. But given the litany of failures in drug development for Alzheimer’s disease, this is a surprising turning point for the field. And while skepticism about the true significance of these findings – for patients, for the fate of similar drugs, for our understanding of the disease – is warranted, the result is significant enough to allow the Alzheimer community to celebrate a possible victoire.

Biogen and Eisai’s drug slowed cognitive decline by 27% over 18 months compared to a placebo in a large trial with nearly 1,800 people with early-stage Alzheimer’s disease. These data make it the first to show clinical benefit in a late-stage study, but it won’t be the first amyloid-targeting drug to hit the market.

That milestone last year went to Aduhelm, also developed by Biogen and Eisai. But that controversial regulatory nod was based on Aduhelm’s ability to get rid of amyloid plaques, which some scientists believe is a major cause of Alzheimer’s disease, not on its ability to slow the cognitive decline of sickness. As a result, Medicare decided not to pay for the drug unless it was administered in a trial that could confirm its benefits. Without a commercial market, Biogen has essentially stopped trying to sell it.

The companies have already applied to the Food and Drug Administration to grant lecanemab so-called “fast track approval” based on its ability to clear amyloid – which is expected to arrive in early 2023. This new data should support full approval. , which would convince insurers to cover it, by the second half of 2023. The clear win for a drug entering a multi-billion dollar market sent shares of Biogen soaring as much as 44% this morning .

But the results come with many caveats. The companies provided the data in a press release, not in a document. Full details will be presented at a conference in late November, and neurologists will dig into them to make sure the drug’s already modest benefits haven’t been oversold.

Lecanemab, like other amyloid-targeting antibodies, also has a safety concern – brain swelling and bleeding. Although for most study participants these side effects were mild, the frequency with which they occurred could have made it easy for doctors to tell which patients in the trial were receiving the drug versus placebo, a situation which may have biased the results.

The biggest asterisk is that lecanemab is not a cure – sadly, it doesn’t even come close. We don’t know how much a modest slowdown in the disease will have on the lives of people with Alzheimer’s disease and their families. And any impact the drug might have would be blunted if the price puts it out of reach.

Another thing the results don’t, as Eisai chief executive Haruo Naito claimed in a press release, “prove the amyloid hypothesis,” the theory that the disease of Alzheimer’s is caused by the protein that clumps together to form plaques on people’s brains. with the disease.

But the results also don’t spell the death knell for the theory that many, myself included, expected.

Over the past two decades, companies have spent hundreds of millions of dollars on drug after drug to reduce these plaques. All of these efforts failed, leading skeptics to wonder if amyloid buildup was a consequence rather than a driver of the disease.

With each new failure, proponents of the amyloid hypothesis offered a few standard explanations: the trial recruited the wrong patients; it was tested too late in the disease to make a difference; the drug didn’t quite work the right way.

And it is true that older studies were sometimes deeply flawed. But it was hard not to see that as an excuse to keep the focus on amyloid. Many critics (again, myself included) felt that it was high time for the pharmaceutical industry to move on – or at the very least to devote a much larger share of research dollars to d other ideas.

The truth now seems somewhere between these extremes. Amyloid isn’t the only driver of disease, but data from Biogen and Eisai confirm that it’s worth targeting.

What’s more exciting is the idea that this early success could accelerate other efforts — efforts that could have a deeper impact on patients’ lives. Alzheimer’s disease experts have long recognized that it will take more than one drug to alter the course of the disease. Perhaps amyloid therapy should be combined with, say, therapy targeting tau tangles or adding a treatment that can prevent neurons from dying.

But arriving at drug combinations has been difficult, if not impossible, without first having at least one treatment with proven clinical benefit. The results of studies of two experimental drugs would be too difficult to analyze. If a trial failed or succeeded, it would be difficult to tell whether the benefit was due to one drug, the other, or the combination. If a safety issue emerged, which drug would be to blame?

University researchers recently launched the first such trial, which studies the effect of combining lecanemab with a tau-targeting drug (also made by Eisai). It took years to take off, and due to its meticulous design, it will take years to perform.

Now, these types of studies should be easier to set up and run, especially if lecanemab or one of the other late-stage amyloid-targeting drugs becomes a routine part of patient care. Alzheimer’s disease.

The good news about lecanemab should not further anchor the field of Alzheimer’s disease in amyloid research, but rather should inspire a series of creative trials that could help bring about more substantial changes in the lives of people with the disease.

Experts will and must comb through the new data with a fine-toothed comb to understand the true value of the new treatment. The field should also embrace the idea that successes are possible – and start pushing hard on ways to improve this one.

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This column does not necessarily reflect the opinion of the Editorial Board or of Bloomberg LP and its owners.

Lisa Jarvis is a Bloomberg Opinion columnist covering biotech, healthcare, and pharmaceuticals. Previously, she was the editor of Chemical & Engineering News.

More stories like this are available at bloomberg.com/opinion

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