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.”
Henrietta Lacks' Cells Enabled Medical Breakthroughs. Is It Time to Finally Retire Them?
Henrietta Lacks, (1920-1951) unknowingly had her cells cultured and used in medical research.
For Victoria Tokarz, a third-year PhD student at the University of Toronto, experimenting with cells is just part of a day's work. Tokarz, 26, is studying to be a cell biologist and spends her time inside the lab manipulating muscle cells sourced from rodents to try to figure out how they respond to insulin. She hopes this research could someday lead to a breakthrough in our understanding of diabetes.
"People like to use HeLa cells because they're easy to use."
But in all her research, there is one cell culture that Tokarz refuses to touch. The culture is called HeLa, short for Henrietta Lacks, named after the 31-year-old tobacco farmer the cells were stolen from during a tumor biopsy she underwent in 1951.
"In my opinion, there's no question or experiment I can think of that validates stealing from and profiting off of a black woman's body," Tokarz says. "We're not talking about a reagent we created in a lab, a mixture of some chemicals. We're talking about a human being who suffered indescribably so we could profit off of her misfortune."
Lacks' suffering is something that, until recently, was not widely known. Born to a poor family in Roanoke, VA, Lacks was sent to live with her grandfather on the family tobacco farm at age four, shortly after the death of her mother. She gave birth to her first child at just fourteen, and two years later had another child with profound developmental disabilities. Lacks married her first cousin, David, in 1941 and the family moved to Maryland where they had three additional children.
But the real misfortune came in 1951, when Lacks told her cousins that she felt a hard "knot" in her womb. When Lacks went to Johns Hopkins hospital to have the knot examined, doctors discovered that the hard lump Henrietta felt was a rapidly-growing cervical tumor.
Before the doctors treated the tumor – inserting radium tubes into her vagina, in the hopes they could kill the cancer, Lacks' doctors clipped two tissue samples from her cervix, without Lacks' knowledge or consent. While it's considered widely unethical today, taking tissue samples from patients was commonplace at the time. The samples were sent to a cancer researcher at Johns Hopkins and Lacks continued treatment unsuccessfully until she died a few months later of metastatic cancer.
Lacks' story was not over, however: When her tissue sample arrived at the lab of George Otto Gey, the Johns Hopkins cancer researcher, he noticed that the cancerous cells grew at a shocking pace. Unlike other cell cultures that would die within a day or two of arriving at the lab, Lacks' cells kept multiplying. They doubled every 24 hours, and to this day, have never stopped.
Scientists would later find out that this growth was due to an infection of Human Papilloma Virus, or HPV, which is known for causing aggressive cancers. Lacks' cells became the world's first-ever "immortalized" human cell line, meaning that as long as certain environmental conditions are met, the cells can replicate indefinitely. Although scientists have cultivated other immortalized cell lines since then, HeLa cells remain a favorite among scientists due to their resilience, Tokarz says.
"People like to use HeLa cells because they're easy to use," Tokarz says. "They're easy to manipulate, because they're very hardy, and they allow for transection, which means expressing a protein in a cell that's not normally there. Other cells, like endothelial cells, don't handle those manipulations well."
Once the doctors at Johns Hopkins discovered that Lacks' cells could replicate indefinitely, they started shipping them to labs around the world to promote medical research. As they were the only immortalized cell line available at the time, researchers used them for thousands of experiments — some of which resulted in life-saving treatments. Jonas Salk's polio vaccine, for example, was manufactured using HeLa cells. HeLa cell research was also used to develop a vaccine for HPV, and for the development of in vitro fertilization and gene mapping. Between 1951 and 2018, HeLa cells have been cited in over 110,000 publications, according to a review from the National Institutes of Health.
But while some scientists like Tokarz are thankful for the advances brought about by HeLa cells, they still believe it's well past time to stop using them in research.
"Am I thankful we have a polio vaccine? Absolutely. Do I resent the way we came to have that vaccine? Absolutely," Tokarz says. "We could have still arrived at those same advances by treating her as the human being she is, not just a specimen."
Ethical considerations aside, HeLa is no longer the world's only available cell line – nor, Tokarz argues, are her cells the most suitable for every type of research. "The closer you can get to the physiology of the thing you're studying, the better," she says. "Now we have the ability to use primary cells, which are isolated from a person and put right into the culture dish, and those don't have the same mutations as cells that have been growing for 20 years. We didn't have the expertise to do that initially, but now we do."
Raphael Valdivia, a professor of molecular genetics and microbiology at Duke University School of Medicine, agrees that HeLa cells are no longer optimal for most research. "A lot of scientists are moving away from HeLa cells because they're so unstable," he says. "They mutate, they rearrange chromosomes to become adaptive, and different batches of cells evolve separately from each other. The HeLa cells in my lab are very different than the ones down the hall, and that means sometimes we can't replicate our results. We have to go back to an earlier batch of cells in the freezer and re-test."
Still, the idea of retiring the cells completely doesn't make sense, Valdivia says: "To some extent, you're beholden to previous research. You need to be able to confirm findings that happen in earlier studies, and to do that you need to use the same cell line that other researchers have used."
"Ethics is not black and white, and sometimes there's no such thing as a straightforward ethical or unethical choice."
"The way in which the cells were taken – without patient consent – is completely inappropriate," says Yann Joly, associate professor at the Faculty of Medicine in Toronto and Research Director at the Centre of Genomics and Policy. "The question now becomes, what can we do about it now? What are our options?"
While scientists are not able to erase what was done to Henrietta Lacks, Joly argues that retiring her cells is also non-consensual, assuming – maybe incorrectly – what Henrietta would have wanted, without her input. Additionally, Joly points out that other immortalized human cell lines are fraught with what some people consider to be ethical concerns as well, such as the human embryonic kidney cell line, commonly referred to as HEK-293, that was derived from an aborted female fetus. "Just because you're using another kind of cell doesn't mean it's devoid of ethical issue," he says.
Seemingly, the one thing scientists can agree on is that Henrietta Lacks was mistreated by the medical community. But even so, retiring her cells from medical research is not an obvious solution. Scientists are now using HeLa cells to better understand how the novel coronavirus affects humans, and this knowledge will inform how researchers develop a COVID-19 vaccine.
"Ethics is not black and white, and sometimes there's no such thing as a straightforward ethical or unethical choice," Joly says. "If [ethics] were that easy, nobody would need to teach it."
An intergalactic explorer on a hypothetical mission to Mars.
Social isolation. Strange pathogens outside. Strategic resource planning. Our Earthbound pandemic-driven social distancing could be mistaken for adapting to another, foreign planet. After all, we're donning all our protective apparel to go on an airplane or to the grocery store, nevertheless to just open our front door. Perhaps this is training for the world galactic visionaries Elon Musk, Jeff Bezos, and Richard Branson see in our future.
"There are parallels to the individual psychological experience, but from an operational standpoint, it is too different."
Ready to go live on Mars or something? Not so fast, experts say. The experience of shelter in place isn't parallel to being a space settler, or even an astronaut.
"Certain aspects are similar, but still, honestly, there are too many differences to say it preps us," says Angelo Vermeulen, co-founder of the art-science collective SEADS (Space Ecologies Art and Design) Network. In 2013, he served as a NASA crew commander for a four-month Mars-on-Earth mission, isolated in a geometric biodome with five others. "There are parallels to the individual psychological experience, but from an operational standpoint, it is too different. You don't need a spacesuit, aren't threatened by a thin atmosphere or worried about being overpowered by radiation."
Outside threats aside, we have a bigger experience gap: Most of us didn't see this pandemic coming and weren't trained to survive the current new normal. NASA astronauts get at least two years of basic training. We received none. Intergalactic explorers understand gravity, air pressure, and other important criteria based on decades of space knowledge. Alternatively, new novel coronavirus data is coming in real time, changing the threats, precautions, and needs dramatically. Things feel a little different when you're winging it.
Lastly, with respect to Apollo 13, space travelers have a timeline for when their experience will be over. There are mishaps, challenges and adjustments, but every well-supported journeyperson leaves Earth with an agenda (and a team back home to help keep them on track).
The pandemic, on the other hand, has no definitive end. It is unclear when a reliable vaccine will be readily available. It is also not known how long we should shelter-in-place, as pulling the trigger too early could bring another wave of illness. We are missing definitive milestones, which, Vermeulen says, would make our isolation experience easier to navigate. "When you're on a mission, the end date is always on the horizon. You can celebrate the midpoint and check off major milestones, which helps."
Also, unlike a kid pretending to be in a rocket, most of us didn't dream of one day being socially isolated for an indeterminate amount of time. "If you're ambitious and working in the field, then it is your goal in life to experience [space and the related isolation]," he says. "With the pandemic, though, nobody chose to do this."
[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.]