How Leqembi became the biggest news in Alzheimer’s disease in 40 years, and what comes next
Betsy Groves, 73, with her granddaughter. Groves learned in 2021 that she has Alzheimer's disease. She hopes to take Leqembi, a drug approved by the FDA last week.
A few months ago, Betsy Groves traveled less than a mile from her home in Cambridge, Mass. to give a talk to a bunch of scientists. The scientists, who worked for the pharmaceutical companies Biogen and Eisai, wanted to know how she lived her life, how she thought about her future, and what it was like when a doctor’s appointment in 2021 gave her the worst possible news. Groves, 73, has Alzheimer’s disease. She caught it early, through a lumbar puncture that showed evidence of amyloid, an Alzheimer’s hallmark, in her cerebrospinal fluid. As a way of dealing with her diagnosis, she joined the Alzheimer’s Association’s National Early-Stage Advisory Board, which helped her shift into seeing her diagnosis as something she could use to help others.
After her talk, Groves stayed for lunch with the scientists, who were eager to put a face to their work. Biogen and Eisai were about to release the first drug to successfully combat Alzheimer’s in 40 years of experimental disaster. Their drug, which is known by the scientific name lecanemab and the marketing name Leqembi, was granted accelerated approval by the U.S. Food and Drug Administration last Friday, Jan. 6, after a study in 1,800 people showed that it reduced cognitive decline by 27 percent over 18 months.
It is no exaggeration to say that this result is a huge deal. The field of Alzheimer’s drug development has been absolutely littered with failures. Almost everything researchers have tried has tanked in clinical trials. “Most of the things that we've done have proven not to be effective, and it's not because we haven’t been taking a ton of shots at goal,” says Anton Porsteinsson, director of the University of Rochester Alzheimer's Disease Care, Research, and Education Program, who worked on the lecanemab trial. “I think it's fair to say you don't survive in this field unless you're an eternal optimist.”
As far back as 1984, a cure looked like it was within reach: Scientists discovered that the sticky plaques that develop in the brains of those who have Alzheimer’s are made up of a protein fragment called beta-amyloid. Buildup of beta-amyloid seemed to be sufficient to disrupt communication between, and eventually kill, memory cells. If that was true, then the cure should be straightforward: Stop the buildup of beta-amyloid; stop the Alzheimer’s disease.
It wasn’t so simple. Over the next 38 years, hundreds of drugs designed either to interfere with the production of abnormal amyloid or to clear it from the brain flamed out in trials. It got so bad that neuroscience drug divisions at major pharmaceutical companies (AstraZeneca, Pfizer, Bristol-Myers, GSK, Amgen) closed one by one, leaving the field to smaller, scrappier companies, like Cambridge-based Biogen and Tokyo-based Eisai. Some scientists began to dismiss the amyloid hypothesis altogether: If this protein fragment was so important to the disease, why didn’t ridding the brain of it do anything for patients? There was another abnormal protein that showed up in the brains of Alzheimer’s patients, called tau. Some researchers defected to the tau camp, or came to believe the proteins caused damage in combination.
The situation came to a head in 2021, when the FDA granted provisional approval to a drug called aducanumab, marketed as Aduhelm, against the advice of its own advisory council. The approval was based on proof that Aduhelm reduced beta-amyloid in the brain, even though one research trial showed it had no effect on people’s symptoms or daily life. Aduhelm could also cause serious side effects, like brain swelling and amyloid related imaging abnormalities (known as ARIA, these are basically micro-bleeds that appear on MRI scans). Without a clear benefit to memory loss that would make these risks worth it, Medicare refused to pay for Aduhelm among the general population. Two congressional committees launched an investigation into the drug’s approval, citing corporate greed, lapses in protocol, and an unjustifiably high price. (Aduhelm was also produced by the pharmaceutical company Biogen.)
To be clear, Leqembi is not the cure Alzheimer’s researchers hope for. While the drug is the first to show clear signs of a clinical benefit, the scientific establishment is split on how much of a difference Leqembi will make in the real world.
So far, Leqembi is like Aduhelm in that it has been given accelerated approval only for its ability to remove amyloid from the brain. Both are monoclonal antibodies that direct the immune system to attack and clear dysfunctional beta-amyloid. The difference is that, while that’s all Aduhelm was ever shown to do, Leqembi’s makers have already asked the FDA to give it full approval – a decision that would increase the likelihood that Medicare will cover it – based on data that show it also improves Alzheimer’s sufferer’s lives. Leqembi targets a different type of amyloid, a soluble version called “protofibrils,” and that appears to change the effect. “It can give individuals and their families three, six months longer to be participating in daily life and living independently,” says Claire Sexton, PhD, senior director of scientific programs & outreach for the Alzheimer's Association. “These types of changes matter for individuals and for their families.”
To be clear, Leqembi is not the cure Alzheimer’s researchers hope for. It does not halt or reverse the disease, and people do not get better. While the drug is the first to show clear signs of a clinical benefit, the scientific establishment is split on how much of a difference Leqembi will make in the real world. It has “a rather small effect,” wrote NIH Alzheimer’s researcher Madhav Thambisetty, MD, PhD, in an email to Leaps.org. “It is unclear how meaningful this difference will be to patients, and it is unlikely that this level of difference will be obvious to a patient (or their caregivers).” Another issue is cost: Leqembi will become available to patients later this month, but Eisai is setting the price at $26,500 per year, meaning that very few patients will be able to afford it unless Medicare chooses to reimburse them for it.
The same side effects that plagued Aduhelm are common in Leqembi treatment as well. In many patients, amyloid doesn’t just accumulate around neurons, it also forms deposits in the walls of blood vessels. Blood vessels that are shot through with amyloid are more brittle. If you infuse a drug that targets amyloid, brittle blood vessels in the brain can develop leakage that results in swelling or bleeds. Most of these come with no symptoms, and are only seen during testing, which is why they are called “imaging abnormalities.” But in situations where patients have multiple diseases or are prescribed incompatible drugs, they can be serious enough to cause death. The three deaths reported from Leqembi treatment (so far) are enough to make Thambisetty wonder “how well the drug may be tolerated in real world clinical practice where patients are likely to be sicker and have multiple other medical conditions in contrast to carefully selected patients in clinical trials.”
Porsteinsson believes that earlier detection of Alzheimer’s disease will be the next great advance in treatment, a more important step forward than Leqembi’s approval.
Still, there are reasons to be excited. A successful Alzheimer’s drug can pave the way for combination studies, in which patients try a known effective drug alongside newer, more experimental ones; or preventative studies, which take place years before symptoms occur. It also represents enormous strides in researchers’ understanding of the disease. For example, drug dosages have increased massively—in some cases quadrupling—from the early days of Alzheimer’s research. And patient selection for studies has changed drastically as well. Doctors now know that you’ve got to catch the disease early, through PET-scans or CSF tests for amyloid, if you want any chance of changing its course.
Porsteinsson believes that earlier detection of Alzheimer’s disease will be the next great advance in treatment, a more important step forward than Leqembi’s approval. His lab already uses blood tests for different types of amyloid, for different types of tau, and for measures of neuroinflammation, neural damage, and synaptic health, but commercially available versions from companies like C2N, Quest, and Fuji Rebio are likely to hit the market in the next couple of years. “[They are] going to transform the diagnosis of Alzheimer's disease,” Porsteinsson says. “If someone is experiencing memory problems, their physicians will be able to order a blood test that will tell us if this is the result of changes in your brain due to Alzheimer's disease. It will ultimately make it much easier to identify people at a very early stage of the disease, where they are most likely to benefit from treatment.”
Learn more about new blood tests to detect Alzheimer's
Early detection can help patients for more philosophical reasons as well. Betsy Groves credits finding her Alzheimer’s early with giving her the space to understand and process the changes that were happening to her before they got so bad that she couldn’t. She has been able to update her legal documents and, through her role on the Advisory Group, help the Alzheimer’s Association with developing its programs and support services for people in the early stages of the disease. She still drives, and because she and her husband love to travel, they are hoping to get out of grey, rainy Cambridge and off to Texas or Arizona this spring.
Because her Alzheimer’s disease involves amyloid deposits (a “substantial portion” do not, says Claire Sexton, which is an additional complication for research), and has not yet reached an advanced stage, Groves may be a good candidate to try Leqembi. She says she’d welcome the opportunity to take it. If she can get access, Groves hopes the drug will give her more days to be fully functioning with her husband, daughters, and three grandchildren. Mostly, she avoids thinking about what the latter stages of Alzheimer’s might be like, but she knows the time will come when it will be her reality. “So whatever lecanemab can do to extend my more productive ways of engaging with relationships in the world,” she says. “I'll take that in a minute.”
“Disinfection Tunnels” Are Popping Up Around the World, Fueled By Misinformation and Fear
A screenshot of a video published by The Guardian of a tunnel used in a Mexican border town to "disinfect" U.S. visitors in an attempt to prevent them from spreading the coronavirus.
In an incident that sparked widespread outrage across India in late March, officials in the north Indian state of Uttar Pradesh sprayed hundreds of migrant workers, including women and children, with a chemical solution to sanitize them, in a misguided attempt to contain the spread of the novel coronavirus.
Since COVID-19 is a respiratory disorder, disinfecting a person's body or clothes cannot protect them from contracting the novel coronavirus, or help in containing the pathogen's spread.
Health officials reportedly doused the group with a diluted mixture of sodium hypochlorite – a bleaching agent harmful to humans, which led to complaints of skin rashes and eye irritation. The opposition termed the instance 'inhuman', compelling the state government to order an investigation into the mass 'chemical bath.'
"I don't think the officials thought this through," says Thomas Abraham, a professor with The University of Hong Kong, and a former consultant for the World Health Organisation (WHO) on risk communication. "Spraying people with bleach can prove to be harmful, and there is no guideline … that recommends it. This was some sort of a kneejerk reaction."
Although spraying individuals with chemicals led to a furor in the South Asian nation owing to its potential dangers, so-called "disinfection tunnels" have sprung up in crowded public places around the world, including malls, offices, airports, railway stations and markets. Touted as mass disinfectants, these tunnels spray individuals with chemical disinfectant liquids, mists or fumes through nozzles for a few seconds, purportedly to sanitize them -- though experts strongly condemn their use. The tunnels have appeared in at least 16 countries: India, Malaysia, Scotland, Albania, Argentina, Colombia, Singapore, China, Pakistan, France, Vietnam, Bosnia and Herzegovina, Chile, Mexico, Sri Lanka and Indonesia. Russian President Vladimir Putin even reportedly has his own tunnel at his residence.
While U.S. visitors to Mexico are "disinfected" through these sanitizing tunnels, there is no evidence that the mechanism is currently in use within the United States. However, the situation could rapidly change with international innovators like RD Pack, an Israeli start-up, pushing for their deployment. Many American and multinational companies like Stretch Structures, Guilio Barbieri and Inflatable Design Works are also producing these systems. As countries gradually ease lockdown restrictions, their demand is on the rise -- despite a stringent warning from the WHO against their potential health hazards.
"Spraying individuals with disinfectants (such as in a tunnel, cabinet, or chamber) is not recommended under any circumstances," the WHO warned in a report on May 15. "This could be physically and psychologically harmful and would not reduce an infected person's ability to spread the virus through droplets or contact. Moreover, spraying individuals with chlorine and other toxic chemicals could result in eye and skin irritation, bronchospasm due to inhalation, and gastrointestinal effects such as nausea and vomiting."
Disinfection tunnels largely spray a diluted mixture of sodium hypochlorite, a chlorine compound commonly known as bleach, often used to disinfect inanimate surfaces. Known for its hazardous properties, the WHO, in a separate advisory on COVID-19, warns that spraying bleach or any other disinfectant on individuals can prove to be poisonous if ingested, and that such substances should be used only to disinfect surfaces.
Considering the effect of sodium hypochlorite on mucous membranes, the European Centre for Disease Prevention and Control, an EU agency focussed on infectious diseases, recommends limited use of the chemical compound even when disinfecting surfaces – only 0.05 percent for cleaning surfaces, and 0.1 percent for toilets and bathroom sinks. The Indian health ministry also cautioned against spraying sodium hypochlorite recently, stating that its inhalation can lead to irritation of mucous membranes of the nose, throat, and respiratory tract.
In addition to the health hazards that such sterilizing systems pose, they have little utility, argues Indian virologist T. Jacob John. Since COVID-19 is a respiratory disorder, disinfecting a person's body or clothes cannot protect them from contracting the novel coronavirus, or help in containing the pathogen's spread.
"It's a respiratory infection, which means that you have the virus in your respiratory tract, and of course, that shows in your throat, therefore saliva, etc.," says John. "The virus does not survive outside the body for a long time, unless it is in freezing temperatures. Disinfecting a person's clothes or their body makes no sense."
Disinfection tunnels have limited, if any, impact on the main modes of coronavirus transmission, adds Craig Janes, director, School of Public Health and Health Systems at Canada's University of Waterloo. He explains that the nature of COVID-19 transmission is primarily from person-to-person, either directly, or via an object that is shared between two individuals. Measures like physical distancing and handwashing take care of these transmission risks.
"My view of these kinds of actions are that they are principally symbolic, indicating to a concerned population that 'something is being done,' to martial support for government or health system efforts," says Janes. "So perhaps a psychological benefit, but I'm not sure that this benefit would outweigh the risks."
"They may make people feel that their risk of infection has been reduced, and also that they do not have to worry about infecting others."
A recent report by Health Care Without Harm (HCWH), an international not-for-profit organization focused on sustainable health care around the world, states that disinfection tunnels have little evidence to demonstrate their efficacy or safety.
"If the goal is to reduce the spread of the virus by decontaminating the exterior clothing, shoes, and skin of the general public, there is no evidence that clothes are an important vector for transmission. If the goal is to attack the virus in the airways, what is the evidence that a 20-30 second external application is efficacious and safe?" the report questions. "The World Health Organization recommends more direct and effective ways to address hand hygiene, with interventions known to be effective."
If an infected person walks through a disinfection tunnel, he would still be infectious, as the chemicals will only disinfect the surfaces, says Gerald Keusch, a professor of medicine and international health at Boston University's Schools of Medicine and Public Health.
"While we know that viruses can be "disinfected" from surfaces and hands, disinfectants can be harmful to health if ingested or inhaled. The underlying principle of medicine is to do no harm, and we always measure benefit against risk when approving interventions. I don't know if this has been followed and assessed with respect to these devices," says Keusch. "It's a really bad idea."
Experts warn that such tunnels may also create a false sense of security, discouraging people from adopting best practice methods like handwashing, social distancing, avoiding crowded places, and using masks to combat the spread of COVID-19.
"They may make people feel that their risk of infection has been reduced, and also that they do not have to worry about infecting others," says Janes. "These are false assumptions, and may lead to increasing rather than reducing transmission."
n artist rendering of a "smart toilet" that gathers biometric data to monitor a person's health in real time.
It looks like an ordinary toilet but it is anything but. The "smart toilet" is the diagnostic tool of the future, equipped with cameras that take snapshots of the users and their waste, motion sensors to analyze what's inside the urine and stool samples, and software that automatically sends data to a secure, cloud-based system that can be easily accessed by your family doctor.
"It's a way of doing community surveillance. If there is a second wave of infections in the future, we'll know right away."
Using urine "dipstick tests" similar to the home pregnancy strips, the smart toilet can detect certain proteins, immune system biomarkers and blood cells that indicate the presence of such diseases as infections, bladder cancer, and kidney failure.
The rationale behind this invention is that some of the best ways of detecting what's going on in our bodies is by analyzing the substances we excrete every day, our sweat, urine, saliva and yes, our feces. Instead of getting sporadic snapshots from doctor's visits once or twice a year, the smart toilet provides continuous monitoring of our health 24/7, so we can catch the tell-tale molecular signature of illnesses at their earliest and most treatable stages. A brainchild of Stanford University researchers, they're now working to add a COVID-19 detection component to their suite of technologies—corona virus particles can be spotted in stool samples—and hope to have the system available within the year.
"We can connect the toilet system to cell phones so we'll know the results within 30 minutes," says Seung-min Park, a lead investigator on the research team that devised this technology and a senior research scientist at the Stanford University School of Medicine. "The beauty of this technology is that it can continuously monitor even after this pandemic is over. It's a way of doing community surveillance. If there is a second wave of infections in the future, we'll know right away."
Experts believe that the COVID-19 pandemic will accelerate the widespread acceptance of in-home diagnostic tools such as this. "Shock events" like pandemics can be catalysts for sweeping changes in society, history shows us. The Black Death marked the end of feudalism and ushered in the Renaissance while the aftershocks of the Great Depression and two world wars in the 20th century led to the social safety net of the New Deal and NATO and the European Union. COVID-19 could fundamentally alter the way we deliver healthcare, abandoning the outdated 20th century brick and mortar fee-for-service model in favor of digital medicine. At-home diagnostics may be the leading edge of this seismic shift and the pandemic could accelerate the product innovations that allow for home-based medical screening.
"That's the silver lining to this devastation," says Dr. Leslie Saxon, executive director of the USC Center for Body Computing at the Keck School of Medicine in Los Angeles. As an interventional cardiologist, Saxon has spent her career devising and refining the implantable and wearable wireless devices that are used to treat and diagnose heart conditions and prevent sudden death. "This will open up innovation—research has been stymied by a lack of imagination and marriage to an antiquated model," she adds. "There are already signs this is happening—relaxing state laws about licensure, allowing physicians to deliver health care in non-traditional ways. That's a real sea change and will completely democratize medical information and diagnostic testing."
Ironically, diagnostics have long been a step-child of modern medicine, even though accurate and timely diagnostics play a crucial role in disease prevention, detection and management. "The delivery of health care has proceeded for decades with a blind spot: diagnostic errors—inaccurate or delayed diagnoses—persist throughout all settings of care and continue to harm an unacceptable number of patients," according to a 2015 National Academy of Medicine report. That same report found as many as one out of five adverse events in the hospital result from these errors and they contribute to 10 percent of all patient deaths.
The pandemic should alter the diagnostic landscape. We already have a wealth of wearable and implantable devices, like glucose sensors to monitor blood sugar levels for diabetics, Apple's smart watch, electrocardiogram devices that can detect heart arrythmias, and heart pacemakers.
The Food and Drug Administration is working closely with in-home test developers to make accurate COVID-19 diagnostic tools readily available and has so far greenlighted three at-home collection test kits. Two, LabCorp's and Everlywell's, use nasal swabs to take samples. The third one is a spit test, using saliva samples, that was devised by a Rutgers University laboratory in partnership with Spectrum Solutions and Accurate Diagnostic Labs.
The only way to safely reopen is through large scale testing, but hospitals and doctors' offices are no longer the safest places.
In fact, DIY diagnostic company Everlywell, an Austin, Texas- based digital health company, already offers more than 30 at-home kits for everything from fertility to food sensitivity tests. Typically, consumers collect a saliva or finger-prick blood sample, dispatch it in a pre-paid shipping envelope to a laboratory, and a physician will review the results and send a report to consumers' smartphones.
Thanks to advances in technology, samples taken at home can now be preserved long enough to arrive intact at diagnostic laboratories. The key is showing the agency "transport and shipping don't change or interfere with the integrity of the samples," says Dr. Frank Ong, Everlywell's chief medical and scientific officer.
Ong is keenly aware of the importance of saturation testing because of the lessons learned by colleagues fighting the SARS pandemic in his family's native Taiwan in 2003. "In the beginning, doctors didn't know what they were dealing with and didn't protect themselves adequately," he says. "But over two years, they learned the hard way that there needs to be enough testing, contact tracing of those who have been exposed, and isolation of people who test positive. The value of at-home testing is that it can be done on the kind of broad basis that needs to happen for our country to get back to work."
Because of the pandemic, new policies have removed some of the barriers that impeded the widespread adoption of home-based diagnostics and telemedicine. Physicians can now practice across state lines, get reimbursed for telemedicine visits and use FaceTime to communicate with their patients, which had long been considered taboo because of privacy issues. Doctors and patients are becoming more comfortable and realizing the convenience and benefits of being able to do these things virtually.
Added to this, the only way to safely reopen for business without triggering a second and perhaps even more deadly wave of sickness is through large-scale testing, but hospitals and doctors' offices are no longer the safest places. "We don't want people sitting in a waiting room who later find out they're positive, and potentially infected everyone, including doctors and nurses," says Dr. Kavita Patel, a physician in Washington, DC who served as a policy director in the Obama White House.
In-home testing avoids the risks of direct exposure to the virus for both patients and health care professionals, who can dispense with cumbersome protective gear to take samples, and also enables people without reliable transportation or child-care to learn their status. "At home testing can be a critical component of our country's overall testing strategy," says Dr. Shantanu Nundy, chief medical officer at Accolade Health and on the faculty of the Milken Institute School of Public Health at George Washington University. "Once we're back at work, we need to be much more targeted, and have much more access to data and controlling those outbreaks as tightly as possible. The best way to do that is by leapfrogging clinics and being able to deliver tests at home for people who are disenfranchised by the current system."
In the not-too-distant future, in-home diagnostics could be a key component of precision medicine, which is customized care tailored specifically to each patient's individual needs. Like Stanford's smart toilet prototype, these ongoing surveillance tools will gather health data, ranging from exposures to toxins and pollutions in the environment to biochemical activity, like rising blood pressure, signs of inflammation, failing kidneys or tiny cancerous tumors, and provide continuous real-time information.
"These can be deeply personalized and enabled by smart phones, sensors and artificial intelligence," says USC's Leslie Saxon. "We'll be seeing the floodgates opening to patients accessing medical services through the same devices that they access other things, and leveraging these tools for our health and to fine tune disease management in a model of care that is digitally enabled."
[Editor's Note: This article was originally published on June 8th, 2020 as part of a standalone magazine called GOOD10: The Pandemic Issue. Produced as a partnership among LeapsMag, The Aspen Institute, and GOOD, the magazine is available for free online.]