Anti-amyloid therapies provide the first FDA-approved option to alter AD pathology, but an understanding of overall utility and value to patients remains in its infancy.
In this episode, Teshamae Monteith, MD, FAAN, speaks with David S. Geldmacher, MD, FACP, FANA, author of the article “Treatment of Alzheimer Disease” in the Continuum® December 2024 Dementia issue.
Dr. Monteith is the associate editor of Continuum® Audio and an associate professor of clinical neurology at the University of Miami Miller School of Medicine in Miami, Florida.
Dr. Geldmacher is a professor and Warren Family Endowed Chair in Neurology and the director of the Division of Cognitive and Behavioral Neurology, Department of Neurology, Marnix E. Heersink School of Medicine at the University of Alabama at Birmingham in Birmingham, Alabama.
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Transcript
Full interview transcript available here
Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum, the premier topic-based neurology clinical review and CME journal from the American Academy of Neurology. Thank you for joining us on Continuum Audio, which features conversations with Continuum's guest editors and authors who are the leading experts in their fields. Subscribers to the Continuum journal can read the full article or listen to verbatim recordings of the article and have access to exclusive interviews not featured on the podcast. Please visit the link in the episode notes for more information on the article, subscribing to the journal, and how to get CME.
Dr Monteith: This is Dr Teshamae Monteith. Today, I'm interviewing Dr David Geldmacher about his article on treatment of Alzheimer's disease, which appears in the December 2024 Continuum issue on dementia. Welcome to our podcast, Dr Geldmacher. How are you?
Dr Geldmacher: I’m very well, thank you. It's a pleasure to be here.
Dr Monteith: Yeah. So, why don't you introduce yourself to our audience?
Dr Geldmacher: Sure. I'm David Geldmacher. I'm a professor of neurology at the University of Alabama in Birmingham and I lead the division of Cognitive and Behavioral Neurology.
Dr Monteith: So, I'm really excited about this, to personally learn, and I know that or neurology community is also really excited about this interview. So, why don't we start off with your main objective.
Dr Geldmacher: So, my main goal in the article was to review the FDA-approved pharmacologic treatments for dementia. There's lots of ways of thinking about treatment of dementia; psychosocial, caregiver support, and so forth. But I really wanted to focus on the issues of drug treatment because that's what has been our backbone for a long time and now has recently expanded.
Dr Monteith: Why don't we talk a little bit about, first of all, the boom in the field? What's that been like?
Dr Geldmacher: So, the big change in the field is over the last several years, we've had treatments become available that actually attack the underlying Alzheimer pathology, and that's new and different. For decades, we've been able to treat the symptoms of the disease, but this is the first time we've really been able to get to the root of the pathology and look toward removing amyloid plaques from the brain.
Dr Monteith: Let's step back a little bit and talk about the framework of diagnosis and how that leads into the therapeutic potential. I know you're going to dive into some of the biologics, but we should probably talk about the kind of holistic approach to considering the diagnosis.
Dr Geldmacher: Sure. So, you know, when someone comes to the clinic with memory complaints, our question we have to ask is, is this neurologic origin, a structural origin like Alzheimer's disease or vascular dementia? Are there complicating factors, the software issues of mood disorders and sleep disorders and pain that can all magnify those symptoms? The clinical reasoning is a critical part of that, but in Alzheimer's disease, typically the problems revolve around difficulty forming new memories of events and activities, the episodic memory. And then it's often accompanied by changes in word finding and semantic knowledge. And those are the things that we look for in the clinic to really point toward an AD diagnosis. And then we support it with exclusion of other causes through blood work and identification of patterns of brain atrophy on MRI. And then most recently in the last couple of years, we've been able to add to that molecular imaging for amyloid with PET scans as well as, most recently, blood-based biomarkers for Alzheimer's pathology. So, it's really been a revolution in the diagnosis over these last several years.
Dr Monteith: And when approaching patients or populations of individuals, there seems to be a real full spectrum with looking at the societal burden, the biological impact, of course, risk factors of primary prevention, and now this whole area of brain health and secondary prevention. How do you kind of tie all of this together when talking to patients and family members?
Dr Geldmacher: Sure. So, the approaches for brain health apply to everyone. In basically every clinic visited, our brain aging and memory clinic, we reviewed lifestyle approaches to brain health like regular physical exercise, healthy diet, cognitive and social stimulation. And those are fundamental to the approach to everyone, whether they have cognitive impairments that are measurable or not. These are all things that are good for our brain health. And then, you know, focusing on the vascular risk factors in particular and working with the patient and their primary care team to ensure that lipids and blood sugar and blood pressure are all in good healthy ranges and being appropriately treated.
Dr Monteith: You know, there's this kind of whole considerations of clinically meaningful endpoints and clinical trials, and even when we're talking to our patients. What would you say the field has kind of identified has the best endpoints in helping patients? Would you call it impaired daily function? Is that like the best hard endpoint? Obviously, there are other things such as caregiver burden, but you know, how do you approach assessing patients?
Dr Geldmacher: Defining the endpoints is very difficult. Typically, if we talk to patients and their families, they would like to have better memory or improve memory. How that applies in everyday life actually is daily function. And so, we focus very much on daily function. And when I talk about our therapies, whether they're symptomatic therapies or the new disease-modifying therapies, I really talk about maintenance of function and delays and decline or slowing of decline, helping to foster the person's independence in the activities that they have and be able to sustain that over the longer term.
Dr Monteith: And when thinking about diagnosis- and we're going to get into treatments, but when thinking about the diagnosis, and of course, it's full-spectrum from mild cognitive impairment to moderate and severe forms of dementia, but who should have CSF testing and PET imaging? Obviously, these are invasive, somewhat invasive and expensive tests. Should all people that walk in the door that have memory complaints? How do you stratify who should have tests?
Dr Geldmacher: I think about this in a big funnel, basically, and the starting point of the funnel, of course, is the person with memory complaints. Then there's that neurologic reasoning. Are these memory complaints consistent with what we expect from the anatomy of Alzheimer's disease, with atrophy in in the hippocampus and temporal lobe? Do they have episodic memory loss or not? That first step is really trying to characterize, do the clinical patterns act like those of Alzheimer's disease or not? And then we follow the Academy of Neurology guidelines, looking for reversible sources of cognitive decline, things like B12 deficiency and depression, sleep disorders and the like, and try to exclude those. We start with structural imaging with everyone, and MRI, typically, that will help us understand vascular burden and patterns of atrophy, looking for things like mesial temporal atrophy or precuneus atrophy that are characteristic of Alzheimer's disease. If those things are all pointing in the direction of AD as opposed to something else, then typically before moving on to CSF or PET scan, we will use blood-based biomarkers, which are one of the big changes in the field in the last year or so, and there are now multiple panels of these available. The downside is they are typically not covered by insurance. On the other hand, they can really help us identify who is likely to have a positive PET scan or positive findings on CSF. We start to provide that counseling and information to the patient before they get to those more definitive tests. We can push people in the other direction. We can say, your blood-based biomarkers are negative or do not indicate AD as the most likely source of your condition now, so let's treat other things. Let's see what else we can focus on. The blood-based biomarkers are now, in our clinic at least, the critical choke point between the routine workout that we've always done on everyone and then the more advanced workup of proving amyloid pathology with CSF or a PET scan.
Dr Monteith: How sensitive are those blood biomarkers and how early are they positive?
Dr Geldmacher: The sensitivity is generally pretty good, in the ninety plus percent range on average and it depends on which panel. And as you point out, when in the course of symptoms that they're done, we know that they become positive and presymptomatic or asymptomatic people. We're using these kinds of markers to screen people for prevention trials. So, I think when someone is symptomatic, they're a good indicator of the presence or absence of AD pathology. Now that doesn't mean the AD pathology is the sole cause of their symptoms. And so, we still need to think about those other things like sleep and mood and so forth. But they do point us in the in the direction of Alzheimer's change.
Dr Monteith: So why don't we talk about some of the more standard older treatments, and it's also important to leave with kind of some rational approach to when we start and what should we be counseling our patients on. So why don't we start with the older, you know, choline esterase inhibitors and then some of the MDA- I guess there's only one modulator, SEPTA modulator.
Dr Geldmacher: So, I've been really fortunate in my career span, the time from the first of those symptomatic agents reaching the market in 1993 to seeing the disease modifying drugs enter the market now. I think most neurologists actually have entered practice after those clinical trials of the colon esterase inhibitors were published. So, one of my goals in this article was to review that primary data and what can we expect from those symptomatic drugs. We know that they are inconsistently effective in mild cognitive impairment, and the Academy of Neurology guidelines says there is not strong evidence to use them in mild cognitive impairment. But in mild AD and beyond, the cholinesterase inhibitors provide meaningful benefits. They delay decline, they can delay nursing home placement. They reduce overall costs of care. So, I think they provide real value. So, in the article I have reviewed what the data looked like on those. My approach is to start with oral Donepezil at five milligrams and increase it to ten in everyone who tolerates the five. If for whatever reason the oral Donepezil is not well tolerated, I'll switch to transdermal rivastigmine to help improve tolerability. There are very few head to head comparisons, but nothing suggests that one of the cholinesterase inhibitors is superior to the other for clinical outcomes, and there's no evidence to support conjoint use of more than one at a time. Should someone be showing decline then on typical cholinesterase inhibitor therapy - and people will, it's often delayed, but the decline will reemerge - then I will add the NMDA receptor, a modulator memantine and titrate that up to full dosing, either 10 mg twice a day for the conventional release or 22 mg extended release. And at that point we're sort of on maximal pharmacologic therapy for Alzheimer's disease. These agents can provide some benefit in other conditions, they're off-label except for Lewy body disease where rivastigmine is labeled. But they can provide benefit across different conditions. And there's some preliminary data, for instance, of acetylcholinesterase inhibitors being helpful in vascular cognitive impairment. So, I will use them, but I expect the greatest response when someone really does follow the patterns of Alzheimer's disease.
Dr Monteith: And you have a great chart, by the way, and nice figures looking at some of the meta-analyses on cognitive outcomes as well as functional outcomes. So, thank you for that.
Dr Geldmacher: In general, all of those tables favor treatment over placebo in the domains of cognition, daily function, neuropsychiatric symptoms. And it's that consistency of result that lets me know that we really are seeing a drug effect, that it's not a class effect with those, that we really are helping our patients. It's not like some studies are positive and some are negative. They are very consistently positive. Small magnitude, but consistently positive.
Dr Monteith: And I know we have a lot of patients coming in where, at least, their caregivers are complaining about agitation, and sleep is also a problem for others. And so how do you help that patient? I know you have a good algorithm that also you included in your article, but why don't you summarize how we should approach these symptoms?
Dr Geldmacher: Sure. So, for nonpsychotic agitation, you know, just restlessness, wandering, pacing and so forth, my first choice is an off-label use of citalopram. And there is good clinical trials evidence to support that. if someone has psychotic agitation that is with delusions or hallucinations and so forth, I think we do need to move to the antipsychotic drugs. And the one drug that is now approved for treatment of agitation and Alzheimer's disease does fall into that antipsychotic category, along with its various black box warnings - and that's brexpiprazole. For many of our patients, getting coverage for that agent is difficult. It's not on many formularies. So, it is something I progress toward rather than start with. Similarly, for sleep, there is one approved agent for sleep, that's a dual orexin agonist. And it shows effectiveness, but can have some negative cognitive effects, and so I tend not to start with that either. My first choice when sleep is the primary issue for our patients with dementia is trazodone, and there are some small, limited studies for it's off-label used to enhance sleep. It’s safe, inexpensive, often effective, and therefore it's my first choice.
Dr Monteith: So, now let's get into the big conversations that everyone is having. Let's talk about the newer disease modifying anti amyloid therapies. Give us a summary dating back 2021 probably, although we can hold the preclinical work, but let's talk about what is available to our patients.
Dr Geldmacher: Sure. And the development of anti-amyloid therapies goes all the way back to 1999. So, it's a pretty long course to get us to where we are today.
Dr Monteith: Yeah, that's why we limited that.
Dr Geldmacher: With that first approved agent with aducanumab in 2021, it received a limited or accelerated approval in FDA parlance. These agents, the aducanumab, lecanemab and donanemab, all approved, are known to remove amyloid pathology from the brain as measured by CSF and/or BIPET. They are amyloid lowering therapies, often called disease-modifying therapies. And across the agents there's some variable results. But if we look at the two with full approval, lecanemab and donanemab, they slow clinical progression by 25% to 35% on average. And that's measured by either cognitive measures or global measures or composite measures, but it's pretty consistent in that range of about one-third slowing. That makes it really difficult to discern in an individual patient, though, because there's so much variability in the progression of the disease already that it can be difficult to tell in one person that these drugs are working. They're also complex to use, so there's a qualification process that involves MRI to exclude things like a high tendency toward hemorrhage. It includes genetic testing for papal E4 status to help us understand the risk for complication, and then once-monthly or twice-monthly infusions with standardized schedule for MRI scanning. So, there's a lot that goes into managing these agents. And they are expensive, and we don't yet know their cost effectiveness. The cost effectiveness of the cholinesterase inhibitors was questioned when they first came out back in the 1990s, and it took five or ten years to really understand that they provided benefit to society and to individuals in those domains of quality of life and return on investment. And we're still learning about that with the disease modifying therapies.
Dr Monteith: So, two questions. One, the case that you presented was an individual having symptoms and kind of voiced their desire to be on these therapies. So, people are going to be asking, coming to clinic asking and then of course, they're going to be people that you select out. So, how do you make that decision to recommend this treatment for patients given the potential risk?
Dr Geldmacher: We've got some really good guidance from appropriate use recommendation papers for aducanumab and lecanemab, and I'm expecting one from donanemab fairly soon. But the key is to identify individualized risks, and that involves knowing their APOE4 status, knowing their- whether they've had microhemorrhages in the brain previously, and then documenting that they really do have amyloid pathology with something like PET scan to establish those baselines. I talk to people about the burden of twice-monthly infusions or, now with donanemab, once-monthly infusions. And for instance, for someone who's got a working caregiver, getting to an infusion center twice a month can be a significant burden. And then if there are complications, frequent MRI scans and so forth. So, we talk about the burden of entering into this therapeutic pathway. The reality is that people who are qualified generally want it. I have relatively few folks who have said, no, these risks are more than I'm willing to accept. For decades my patients have said, anything you can do to slow this down, I'm willing to try. And now we're seeing that translated to reality with people willing to accept high-risk, high-cost treatments with the chance of slowing their individual progression.
Dr Monteith: And how do you select between the two treatments?
Dr Geldmacher: So far that's been easy because donanemab's not readily available.
Dr Monteith: Outside of clinical trials, right?
Dr Geldmacher: Exactly. For prescription use, it's coming in - the first cases have now been infused - but it's not generally available. Nonetheless, what I will do for patients in this is look at the risk tables. So donanemab appears to have in general some higher rates of the Aria complications, amyloid-related imaging anomalies, and some people are going to be more risk tolerant of that for the payoff of potentially faster response. The donanemab trials restructured that. They did their first assessment of effectiveness. I had amyloid removal at six months and a significant proportion of people were eligible to discontinue treatment at six months because their amyloid was below treatable thresholds. So higher risk, perhaps faster action and fewer infusions for donanemab. Lecanemab we have more direct experience with, and between the two of them, the eighteen month outcomes are pretty much the same and indistinguishable. So are we in it for a quick hit, or are we in it for the long race? And different patients and different families will have differing opinions on where they want to accept that risk and burden and so forth. But so far, the data don't indicate a lot of difference in their longer-term outcomes. We still have plenty to learn.
Dr Monteith: And so, it sounds like, as you mentioned, we're looking at eighteen months out for kind of a hard outcome, and that there is a lot of variability in response rate. How are you tracking patients- you know about the imaging, so just in terms of clinical outcomes and efficacy?
Dr Geldmacher: Sure. So, for Medicare to reimburse on these treatments, people need to be enrolled in a registry program - and there are several of these, CMS runs one of their own. But the requirement for that is, every six months, to do cognitive and functional outcomes through the first two years. Cognitive outcomes are up to the clinician, but things like the mini mental state exam, the MoCA, are appropriate. In our own program, we use something we developed locally called the Alabama Brief Cognitive Screener. As for the cognitive outcomes and then for functional, we use an instrument called the General Activities of Daily Living Scale, but there are many other ADL scales that could be used as well. CMS does not mandate specific tests. Since the progression of the disease is variable to begin with, we don't really know how to interpret these results in reference to whether the drug is working, but I can tell a patient or a family member, your scores are stable, or, you have a decline of three points in this test. That's typical for this duration of illness. But there isn't a good way to know whether the drug is working in this person at this time, at least with our current levels of data.
Dr Monteith: So, I think we have to talk about health equity, and it sounds like Medicare is reimbursing for some of us. We look at different socioeconomic backgrounds, educational backgrounds, race, ethnicity. Not everyone is aware of these treatments. So, how do we get more patients to become aware of these treatments? And how do we get them to more people to help people?
Dr Geldmacher: Yeah, I mean, that's- it's a major, major issue of inequity in our population. We've done some work at UAB looking at the flow of members of minority communities into memory clinics. So, we know that the overall population of, and I'll choose, for an example, blacks and African Americans, that they are represented a much higher rate in our overall UAB treatment population than they are in our memory clinic population. So, they're not even getting to us in the specialty clinic at the same rates as other segments of our population. We also know that blacks and African Americans in our population are not receiving PET scans as often as the overall treatment population. So yes, there are real, real problems with access. There are cultural issues behind this as well. And in many communities, a change in cognition, a loss of memory is an expected part of the aging process rather than recognized as a disease. So, people who come to us from minority communities are often further along in the course of cognitive and functional decline and beyond the point where they might qualify for the disease-modifying therapies, where early AD is the sort of defining boundary. So, I think more awareness and more screening in primary care settings, perhaps more community outreach to let people know that changes in memory that affect daily function are not normal as part of the aging process and should be evaluated for intervention. So, there's lots of places in our healthcare community where we could foster better outreach, better knowledge to get more folks access to the medicines. And this is before we even get to cost.
Dr Monteith: Yeah, yeah. And obviously, there's some stigma as well.
Dr Geldmacher: That's right.
Dr Monteith: Really recognizing what the issues are and diving and asking those questions and funding research that asks those questions, as you mentioned, is really important. And then you have also a nice area where, you know, looking on the impact of treatments on caregiver-related outcomes, and of course ultimately want to keep patients out of nursing homes and prevent death. And so, can you talk a little bit about that? And, you know, mainly the caregiver burden.
Dr Geldmacher: So, my research in that area goes back a long way now. But I learned early in the course of therapy that many times the outcome that the family is noticing for symptomatic therapies is not a change in the patient's memory per se, but that there is less work involved in the caregiving. Less time is spent in direct caregiving roles. The patient may shadow less and because they have better independent cognition. I remember one family member once told me, the medicine you started is a godsend because now I can go to the bathroom by myself and he's not pounding on the door saying where are you, where are you. He's able to recall long enough that I'm in the bathroom that I have that moment of privacy. That was very meaningful to me to hear that. So.
Dr Monteith: Cool. So why don't you just help us wrap this up and just give us, like, three main takeaway points that we should be getting out of your article?
Dr Geldmacher: The three points that I would emphasize from my article is that the symptomatic therapies provide meaningful benefits and measurable, consistent, meaningful benefits. The second is that those benefits extend beyond things like cognitive test scores and into things like caregiver well-being and maintenance of independence in the home environment. And the third is that the disease-modifying therapies are an exciting opportunity to modify the pathology, but we still are learning about their cost effectiveness and their long-term benefit both to individuals and to society. But the only way we're going to learn that is by using them. And that was the experience that we gained from the symptomatic therapies that took use in the community for years before we really began to understand their true value.
Dr Monteith: Thank you. That was excellent. And I put you on the spot, too.
Dr Geldmacher: No problem.
Dr Monteith: Again, today I've been interviewing Dr David Geldmacher, whose article on treatment of Alzheimer's disease appears in the most recent issue of Continuum on Dementia. Be sure to check out Continuum audio episodes from this and other issues. And thank you to our listeners for joining today.
Dr Monteith: This is Dr Teshamae Monteith, associate editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in depth and clinically relevant information important for neurology practitioners. Use this link in the episode notes to learn more and subscribe. AAN members, you can get CME for listening to this interview by completing the evaluation at contentpub.com/AudioCME. Thank you for listening to Continuum Audio.
