Optimism for New AD Biomarkers and Treatments
SAN DIEGO – Emerging biomarkers and treatments offer more options to diagnose and manage Alzheimer’s disease (AD) and related dementias, but high costs and potentially serious complications mean using them with caution, said a presenter at the annual meeting of the American College of Physicians.
Dementia prevalence is increasing as the proportion of the U.S. population older than 65 rises, said Zaldy Tan, MD, professor of neurology at Cedars-Sinai Medical Center, Los Angeles. AD deaths more than doubled between 2000 and 2018, he noted, while deaths from HIV infection, stroke, and heart disease decreased.
Most people in the United States who have AD are White, but studies suggest that, compared with Whites, the risk of AD is two times higher in Blacks and 1.5 times higher in Hispanics . “These data suggest that both genes and social determinants of health are at play,” Dr. Tan said.
Diagnosis of Alzheimer’s disease
The different types of dementia make it challenging for primary care physicians to identify the cause of cognitive impairment. “Even though AD is the most common type, clinicians should keep in mind that another type of dementia may be the cause of cognitive impairment,” Dr. Tan cautioned. Other dementia diagnoses include vascular, Lewy body, and frontotemporal.
Diagnostic criteria for AD include evidence of significant cognitive decline in at least one cognitive domain that interferes with independence in everyday activities, as well as the absence of another mental disorder or delirium that would explain the cognitive deficits.
“We see many patients with depressive symptoms and mild cognitive impairment, and it is not always easy to tell which of them have dementia because of the overlap in the symptoms of depression and AD,” said internist Roderick Kim, MD, of Grand Rapids, Mich., who attended the session.
It can be challenging to convince patients to undergo the appropriate diagnostic workup, Dr. Kim said. “This can delay treatment, so it is important to explain to patients that cognitive decline can progress quickly and that there are treatment options to slow it down.”
Why do we need biomarkers for Alzheimer’s disease?
AD is characterized by a long preclinical phase with no specific symptoms other than the typical signs and symptoms of aging, Dr. Tan said. That means cognitive impairment progresses rapidly after diagnosis in most patients with AD.
“In most cases, an accurate history, physical and neurologic examinations, basic labs, and neuroimaging are sufficient for memory loss evaluation. However, as more disease-modifying therapies come to market, biomarkers will rise in importance in primary care,” he said.
This long asymptomatic phase of AD creates the need for diagnostic biomarkers for an earlier diagnosis, he said. Amyloid-beta and tau deposits in PET images and the levels of amyloid-beta seeds, phosphorylated tau, and neurofilament light chain in the cerebrospinal fluid can be used as diagnostic biomarkers in patients with suspected AD. Emerging blood biomarkers for earlier detection include the levels of amyloid-beta1–42, phosphorylated tau, and neurofilament light chain.
With biomarkers and other new tools for the diagnosis of dementia in primary care, Dr. Tan said: “The greatest challenge is cost, as blood-based biomarkers are not currently covered by insurance and still rather costly. In addition, blood-based biomarkers will need to receive [Food and Drug Administration] approval in order to have more widespread availability.”
New and emerging therapies for Alzheimer’s disease
There are two classes of FDA-approved medications to manage cognitive symptoms of dementia: acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists. The selections may be trial and error for each patient, Dr. Tan said.
“The approved medications can exert subtle benefits that are clinically observable. Thus, barring any contraindications or intolerance, most patients with AD would benefit from a trial of one or both of these medication classes,” said Dr. Tan. He added that it is equally important to wean off and discontinue these medications if there is intolerance or lack of a subjective or objective beneficial response.
Other medications are available for some of the most common behavioral problems associated with dementia, such as agitation, depression, and disorientation. Dr. Tan advised not to prescribe behavioral medications until nonpharmacologic interventions prove to be ineffective or impractical. Behavioral medications have many side effects, some of which are potentially serious, he said, so the risk-benefit ratio should be considered.
In his own practice, when nonpharmacologic strategies do not improve the behavioral symptoms of dementia, Dr. Tan said that, “in cases where a person is at risk of harm to themselves or others, a discussion with the patient and their caregivers about the pros and cons of medications to treat the behavior need to be had. Careful monitoring of the response and dose escalation or deprescribing when appropriate is important to keep in mind.”
Disease-modifying agents have recently provided new hope for AD treatment. Aducanumab and lecanemab, both monoclonal antibodies that target amyloids, are the first two drugs that received accelerated FDA approval for AD.
Although these monoclonal antibodies can help clear deposited amyloid plaques and show some benefit in slowing cognitive impairment in clinical trials, the real-world benefits were unclear enough for Medicare to limit coverage to people enrolled in approved studies to gather more data. Additionally, these agents can cause potentially amyloid-related imaging abnormalities, which may indicate edema, effusion, or microhemorrhage. Therefore, clinicians need to have a clear conversation of risks and benefits with patients and caregivers about these treatments.
Looking ahead
When asked about the most promising emerging technologies or techniques related to dementia diagnosis and management, Dr. Tan noted that multiple technology companies and start-ups are looking for new ways to detect dementia earlier or keep persons with dementia safe at home. Some devices deliver brain waves, computerized brain games or tests, automated pill dispensers, and fall monitors.
“Some of these are potentially helpful, but not every person with dementia will benefit. In addition, most of these technologies are out-of-pocket expenses for the patients and their families. It is important to know what is out there but also be cautious about outrageous claims,” he added.
Dr. Tan reported no relationships with entities whose primary business is producing, marketing, selling, reselling, or distributing health care products used by or on patients.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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