New Alzheimer’s Drug Reduces Cognitive Decline, Say Biotech Firms

JOHN DANKOSKY: This is Science Friday. I’m John Dankosky, in for Ira Flatow.

Later this hour, how farmers in Bangladesh are capturing monsoon rains for the next dry season. It’s an invisible water machine. Plus, a conversation with a pioneer in science radio, Jim Metzner. We’ll talk about the lessons he’s learned from carefully listening to the pulse of our planet.

But first, this week, the biotech firms Biogen and Eisai released preliminary data from the clinical trials for their new Alzheimer’s drug. They say the drug is effective in reducing cognitive decline by 27% for patients in the trial. And it appears likely the medicine will get the FDA’s approval by the end of the year.

All this comes after the recent controversy surrounding Biogen’s previous Alzheimer’s drug Aduhelm, which Medicare and other private insurers will not cover.

Joining me now to talk more about this and other top science stories of the week is my guest Roxanne Khamsi, who’s a science journalist based in Montreal, Quebec, Canada. Roxanne, welcome back to Science Friday.

ROXANNE KHAMSI: Hi, John. It’s great to be here.

JOHN DANKOSKY: So to start off, tell us more about this new intravenous Alzheimer’s medicine, lecanemab. How effective is it?

ROXANNE KHAMSI: Well, as you say, it only seems to slow the effect of cognitive decline by about a quarter. And really, it’s on the scale from 0 to 18, people were being tested on this cognitive test, called the Clinical Dementia Rating. And they found that people, over 18 months, who were on the drug, did 0.45 points better. So not quite a stunning difference, I would say, than those who didn’t receive the drug.

So I mean, it kind of comes down to how you calculate it. I think the interesting thing here is that we’ve gone almost 20 years without new drugs for Alzheimer’s. And now, in the last two years, this is the second one. As you mentioned, the first one has not been a home run for the drug companies and for patients. So it’s a little bit of wait-and-see with this one, too, I think.

JOHN DANKOSKY: Yeah. And I think a lot of the reaction to it is because we haven’t had a new drug in 20 years, and there’s just a lot of excitement about anything that seems to move the needle. This is part of a study looking at the underlying science of what causes Alzheimer’s. So what does all this tell us about how amyloid plaques work?

ROXANNE KHAMSI: Yes. And as you mentioned, anything that moves the needle is important because Alzheimer’s affects so many people in the US and the world. And for the last 15 years or so, the predominant theory has been that these plaques form in the brain– amyloid toxins– and that clearing those toxins somehow will reduce the cognitive decline.

That being said, just in the last year, there was an investigation suggesting that maybe some of the data that prompted this whole interest in amyloid might have been from manipulated data in a study. So there’s a little bit of a question mark hanging over that as well.

JOHN DANKOSKY: And there’s some skepticism about this drug for all the reasons we just laid out. What are some of the other concerns that we’re hearing from people this week?

ROXANNE KHAMSI: Well, nothing is without cost, I guess, sometimes with drugs– not just the price tag. And for the one that you mentioned that Medicare doesn’t cover, it’s $56,000 a year. But in terms of the side effects, there can be some brain swelling. It could be temporary. But any time your brain is swelling or acting unusual, it’s not necessarily a great thing.

So I think doctors and patients, if this drug gets approved, will have to weigh a lot of different factors.

JOHN DANKOSKY: We’ll continue to follow that story in the weeks and months ahead.

Now, this next story you brought us is going in a different direction– deep inside the Earth. And I don’t know– dare I say– it might even be a little bit of a sparkly story. Scientists have found a diamond that suggests a whole lot of water in the Earth’s mantle. So how could a diamond tell us that, Roxanne?

ROXANNE KHAMSI: Yes. I love talking about diamonds. Let’s talk about diamonds all the time.

[LAUGHTER]

So this was a gem-quality diamond, but it had a flaw in it. It had a beautiful flaw, you might say, that actually gives us a clue about what’s going on deep inside the Earth. So we don’t really have a great way to look at the Earth’s mantle because it’s so far down deep below us. And yet, there’s this question of, what’s there?

So this impurity, this imperfection in this diamond– it’s kind of like a cloudy blue-white haze– it tells us that there is potentially some water in the mantle. And how the water got there, we don’t know. We have some questions. But I love the fact that this tiny diamond is giving us a picture into what might be going on beneath the surface of the Earth.

JOHN DANKOSKY: So a diamond with an impurity like this might actually be a more valuable diamond for science?

ROXANNE KHAMSI: Yes. And unfortunately, they found one of these kinds of gems before– about a decade ago– and it was also miraculously potentially providing clues to whether there’s water in the mantle of the Earth. But they destroyed it in the process of analyzing it.

So hopefully, this time we’ll be able to learn more.

JOHN DANKOSKY: And that they can take better care of the diamond.

ROXANNE KHAMSI: Yes, destroyed diamonds never are never good.

JOHN DANKOSKY: Oh, my goodness. Well, speaking of traveling back in time and finding unusual things about the Earth– so scientists have analyzed an 80-million-year-old bird skull. And it turns out, Roxanne, that ancient birds might have been just as smart as current ones. How did they figure this out?

ROXANNE KHAMSI: Yes. And let’s also say that current birds are actually not that bird-brained. I did not know this, but living birds today have brains that are more complex than any other animals besides mammals. So actually, let’s give some birds some respect for their brains.

What had happened was researchers found this skull that was about 80 million years old. And it has a structure that they’re able to use a CT scan to look and analyze in slices. And they can create a virtual reconstruction of what this bird’s brain was. And it gives them clues to the structure and how it might have been actually able to function a little bit better than other brains out there 80 million years ago.

JOHN DANKOSKY: So what does this tell us about the bird family tree– the birds that may be descended from this 80-million-year-old relatively smart bird?

ROXANNE KHAMSI: Yes. So the structure of the brain here is it’s kind of flexed. It flexes downwards. And it looks more like modern hummingbirds rather than the brain of some of the ancient dinosaurs that might have been related to it. So it tells us that maybe around this time there was a divergence and birds had this new formatting structure that gave them maybe even a better ability to fly. We don’t know. But there’s a lot of conjecture, a lot of speculation, that there was a branching, potentially, off of some of the older types of birds, dinosaurs, and things like that. It took flight, if you will, this new kind of brain.

JOHN DANKOSKY: Now, there’s another study that you brought us here that I think it helps to answer one of the questions I’ve always had about just being human– that feeling of being sick. Like, what gives us that feeling like, oh, I’m not well today? And we’re starting to learn a little bit more about that kind of icky feeling. Tell us more about this study.

ROXANNE KHAMSI: Yes. So we’re going from brains 80 million years ago in birds to our brains today. And what scientists found is that they looked at some of the neurons in the brain stem of mice, which then they hope to say it’s like ours because we’re not that different from mice as much as we want to believe– and these neurons seem to regulate some of those very common symptoms across all different kinds of illnesses that we get.

So I don’t know about you, but sometimes when I’m sick, I lose my appetite, I get lethargic, I just want to snooze. Sometimes I wish my doctor would just prescribe watching movies or something like that because that’s all I want to do. So it seems that the mice had the same effects.

So they did a lot of tricky, sophisticated work to be able to turn on these neurons even when the mice weren’t sick from an actual pathogen. And they found the same lethargy and loss of appetite in the animals, really cluing us in, that this might be an area for us to pay more attention to in terms of what makes us feel the way we do when we’re sick.

JOHN DANKOSKY: Whenever we see studies that are done in mice, there is always a little bit of a red flag there. Like, mice aren’t exactly like humans. Is this the sort of study, Roxanne, that you think, I don’t know, might be something worth looking more into?

ROXANNE KHAMSI: I think so. I do want to say that one of the interesting caveats is all the mice in the study were male. So it would be nice if they actually threw some female mice in there, too, just for kicks. But I do think that this isn’t something where the mice have to perform some sophisticated mental task. It’s really a basic function of behavior from being sick. So I would not be surprised– I’m not a scientist, obviously– but I wouldn’t be surprised if we perhaps find some clues in our own brain stem about why we feel the way we do when we’re sick.

JOHN DANKOSKY: Well, I want to close with I think a really hopeful and interesting story, and something I didn’t know was possible. Researchers are looking into how to make false teeth into hearing aids. So how exactly does this work?

ROXANNE KHAMSI: Yes, this might be a preview into how I will listen to Science Friday 40 years from now.

[LAUGHTER]

If I lose my front teeth especially.

JOHN DANKOSKY: Your front teeth especially. OK, interesting. Tell us more.

ROXANNE KHAMSI: Yes. Yes. And not just because they’re huge. So scientists essentially were looking for different ways to enhance hearing. Because a lot of us are either losing our hearing or have had some hearing impairment. And what we typically know about is these hearing aids that go in our ears.

But what if the hearing aids went in our mouths, is the kind of idea behind all this. So they want to engineer a tooth implant that can function like a hearing aid– so picking up sound in our teeth. Because essentially, even our ears are picking up sound, ultimately, through bones and things like that. So we’re trying to get good vibrations here.

They wanted to test whether implants that were already in people– they had 38 participants in the study. They found that the implants actually conducted sound better than regular natural teeth, and that the implants in the front of the mouth were particularly suited to picking up sound better than ones like deep in the back of the mouth, like molars and things like that. So now they might want to engineer something that specifically functions to act as a hearing aid and a tooth implant. It’s a two-in-one.

JOHN DANKOSKY: A two-in-one. But would it require you to– I don’t know– pull out one of your front teeth in order to make this work?

ROXANNE KHAMSI: They don’t say in the paper whether they would ask people to do that. But I know plenty of people that have implants. Somebody in my family is this week undergoing an implant procedure. So let’s just say they’re not suggesting you ask your friend to punch you in the face so that you can get a hearing aid. But there might be an opportunity for people that are looking to upgrade their implants to really upgrade their implants.

JOHN DANKOSKY: That’s so interesting. Well, we’ll have to keep watching that technology as it develops.

I want to thank my guest, Roxanne Khamsi. She’s a science journalist based in Montreal, Quebec, Canada. Always good to talk to you, Roxanne.

ROXANNE KHAMSI: Thank you, John. I appreciate it very much.

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