How Leqembi became the biggest news in Alzheimer’s disease in 40 years, and what comes next
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.”
It looked like only good things were ahead of Taylor Schreiber in 2010.
Schreiber had just finished his PhD in cancer biology and was preparing to return to medical school to complete his degree. He also had been married a year, and, like any young newlyweds up for adventure, he and his wife Nicki decided to go backpacking in the Costa Rican rainforest.
He was 31, and it was April Fool's Day—but no joke.
During the trip, he experienced a series of night sweats and didn't think too much about it. Schreiber hadn't been feeling right for a few weeks and assumed he had a respiratory infection. Besides, they were sleeping outdoors in a hot, tropical jungle.
But the night sweats continued even after he got home, leaving his mattress so soaked in the morning it was if a bucket of water had been dumped on him overnight. On instinct, he called one of his thesis advisors at the Sylvester Comprehensive Cancer Center in Florida and described his symptoms.
Dr. Joseph Rosenblatt didn't hesitate. "It sounds like Hodgkins. Come see me tomorrow," he said.
The next day, Schreiber was diagnosed with Stage 3b Hodgkin Lymphoma, which meant the disease was advanced. He was 31, and it was April Fool's Day—but no joke.
"I was scared to death," he recalls. "[Thank] goodness it's one of those cancers that is highly treatable. But being 31 years old and all of a sudden being told that you have a 30 percent of mortality within the next two years wasn't anything that I was relieved about."
For Schreiber, the diagnosis was a personal and professional game-changer. He couldn't work in the hospital as a medical student while undergoing chemotherapy, so he wound up remaining in his post-doctorate lab for another two years. The experience also solidified his decision to apply his scientific and medical knowledge to drug development.
Today, now 39, Schreiber is co-founder, director and chief scientific officer of Shattuck Labs, an immuno-oncology startup, and the developer of several important research breakthroughs in the field of immunotherapy.
After his diagnosis, he continued working full-time as a postdoc, while undergoing an aggressive chemotherapy regimen.
"These days, I look back on [my cancer] and think it was one of the luckiest things that ever happened to me," he says. "In medical school, you learn what it is to treat people and learn about the disease. But there is nothing like being a patient to teach you another side of medicine."
Medicine first called to Schreiber when his maternal grandfather was dying from lung cancer complications. Schreiber's uncle, a radiologist at the medical center where his grandfather was being treated, took him on a tour of his department and showed him images of the insides of his body on an ultrasound machine.
Schreiber was mesmerized. His mother was a teacher and his dad sold windows, so medicine was not something to which he had been routinely exposed.
"This weird device was like looking through jelly, and I thought that was the coolest thing ever," he says.
The experience led him to his first real job at the Catholic Medical Center in Manchester, NH, then to a semester-long internship program during his senior year in high school in Concord Hospital's radiology department.
"This was a great experience, but it also made clear that there was not any meaningful way to learn or contribute to medicine before you obtained a medical degree," says Schreiber, who enrolled in Bucknell College to study biology.
Bench science appealed to him, and he volunteered in Dr. Jing Zhou's nephrology department lab at the Harvard Institutes of Medicine. Under the mentorship of one of her post-docs, Lei Guo, he learned a range of critical techniques in molecular biology, leading to their discovery of a new gene related to human polycystic kidney disease and his first published paper.
Before his cancer diagnosis, Schreiber also volunteered in the lab of Dr. Robert "Doc" Sackstein, a world-renowned bone marrow transplant physician and biomedical researcher, and his interests began to shift towards immunology.
"He was just one of those dynamic people who has a real knack for teaching, first of all, and for inspiring people to want to learn more and ask hard questions and understand experimental medicine," Schreiber says.
It was there that he learned the scientific method and the importance of incorporating the right controls in experiments—a simple idea, but difficult to perform well. He also made what Sackstein calls "a startling discovery" about chemokines, which are signaling proteins that can activate an immune response.
As immune cells travel around our bodies looking for potential sources of infection or disease, they latch onto blood vessel walls and "sniff around" for specific chemical cues that indicate a source of infection. Schreiber and his colleagues designed a system that mimics the blood vessel wall, allowing them to define which chemical cues efficiently drive immune cell migration from the blood into tissues.
Schreiber received the best overall research award in 2008 from the National Student Research Foundation. But even as Schreiber's expertise about immunology grew, his own immune system was about to fight its hardest battle.
After his diagnosis, he continued working full-time as a postdoc in the lab of Eckhard Podack, then chair of the microbiology and immunology department at the University of Miami's Leonard M. Miller School of Medicine.
At the same time, Schreiber began an aggressive intravenous chemotherapy regimen of adriamycin, bleomycin, vincristine and dacarbazine, every two weeks, for 6 months. His wife Nicki, an obgyn, transferred her residency from Emory University in Atlanta to Miami so they could be together.
"It was a weird period. I mean, it made me feel good to keep doing things and not just lay idle," he said. "But by the second cycle of chemo, I was immunosuppressed and losing my hair and wore a face mask walking around the lab, which I was certainly self-conscious. But everyone around me didn't make me feel like an alien so I just went about my business."
The experience reinforced his desire to stay in immunology, especially after having taken the most toxic chemotherapies.
He stayed home the day after chemo when he felt his worst, then rested his body and timed exercise to give the drugs the best shot of targeting sick cells (a strategy, he says, that "could have been voodoo"). He also drank "an incredible" amount of fluids to help flush the toxins out of his system.
Side effects of the chemo, besides hair loss, included intense nausea, diarrhea, a loss of appetite, some severe lung toxicities that eventually resolved, and incredible fatigue.
"I've always been a runner, and I would even try to run while I was doing chemo," he said. "After I finished treatment, I would go literally 150 yards and just have to stop, and it took a lot of effort to work through it."
The experience reinforced his desire to stay in immunology, especially after having taken the most toxic chemotherapies.
"They worked, and I could tolerate them because I was young, but people who are older can't," Schreiber said. "The whole field of immunotherapy has really demonstrated that there are effective therapies out there that don't come with all of the same toxicities as the original chemo, so it was galvanizing to imagine contributing to finding some of those."
Schreiber went on to complete his MD and PhD degrees from the Sheila and David Fuente Program in Cancer Biology at the Miller School of Medicine and was nominated in 2011 as a Future Leader in Cancer Research by the American Association for Cancer Research. He also has numerous publications in the fields of tumor immunology and immunotherapy.
Sackstein, who was struck by Schreiber's enthusiasm and "boundless energy," predicts he will be a "major player in the world of therapeutics."
"The future for Taylor is amazing because he has the capacity to synthesize current knowledge and understand the gaps and then ask the right questions to establish new paradigms," said Sackstein, currently dean of the Herbert Wertheim College of Medicine at Florida International University. "It's a very unusual talent."
Since then, he has devoted his career to developing innovative techniques aimed at unleashing the immune system to attack cancer with less toxicity than chemotherapy and better clinical results—first, at a company called Heat Biologics and then at Pelican Therapeutics.
His primary work at Austin, Texas-based Shattuck is aimed at combining two functions in a single therapy for cancer and inflammatory diseases, blocking molecules that put a brake on the immune system (checkpoint inhibitors) while also stimulating the immune system's cancer-killing T cells.
The company has one drug in clinical testing as part of its Agonist Redirected Checkpoint (ARC) platform, which represents a new class of biological medicine. Two others are expected within the next year, with a pipeline of more than 250 drug candidates spanning cancer, inflammatory, and metabolic diseases.
Nine years after his own cancer diagnosis, Schreiber says it remains a huge part of his life, though his chances of a cancer recurrence today are about the same as his chances of getting newly diagnosed with any other cancer.
"I feel blessed to be in a position to help cancer patients live longer and could not imagine a more fulfilling way to spend my life," he says.
The Stunning Comeback of a Top Transplant Surgeon Who Got a New Heart at His Own Hospital
Having spent my working life as a transplant surgeon, it is the ultimate irony that I have now become a heart transplant patient. I knew this was a possibility since 1987, when I was 27 years old and I received a phone call from my sister-in-law telling me that my 35-year-old brother, Rich, had just died suddenly while water skiing.
Living from one heartbeat to the next I knew I had to get it right and nail my life—and in that regard my disease was a blessing.
After his autopsy, dots were connected and it was clear that the mysterious heart disease my father had died from when I was 15 years old was genetic. I was evaluated and it was clear that I too had inherited cardiomyopathy, a progressive weakening condition of the heart muscle that often leads to dangerous rhythm disturbances and sudden death. My doctors urged me to have a newly developed device called an implantable cardioverter-defibrillator (ICD) surgically placed in my abdomen and chest to monitor and shock my heart back into normal rhythm should I have a sudden cardiac arrest.
They also told me I was the first surgeon in the world to undergo an ICD implant and that having one of these devices would not be compatible with the life of a surgeon and I should change careers to something less rigorous. With the support of a mentor and armed with what the British refer to as my "bloody-mindedness," I refused to give up this dream of becoming a transplant surgeon. I completed my surgical training and embarked on my career.
What followed were periods of stability punctuated by near-death experiences. I had a family, was productive in my work, and got on with life, knowing that this was a fragile situation that could turn on its head in a moment. In a way, it made my decisions about how to spend my time and focus my efforts more deliberate and purposeful. Living from one heartbeat to the next I knew I had to get it right and nail my life—and in that regard my disease was a blessing.
In 2017 while pursuing my passion for the outdoors in a remote part of Patagonia, I collapsed from bacterial pneumonia and sepsis. Unknowingly, I had brought in my lungs one of those super-bugs that you read about from the hospital where I worked. Several days into the trip, the bacteria entered my blood stream and brought me as close to death as a human can get.
I lay for nearly 3 weeks in a coma on a stretcher in a tiny hospital in Argentina, septic and in cardiogenic shock before stabilizing enough to be evaced to NYU Langone Hospital, where I was on staff. I awoke helpless, unable to walk, talk, or swallow food or drink. It was a long shot but I managed to recover completely from this episode; after 3 months, I returned to work and the operating room. My heart rebounded, but never back to where it had been.
Then, on the eve of my mother's funeral, I arrested while watching a Broadway show, and this time my ICD failed to revive me. There was prolonged CPR that broke my ribs and spine and a final shock that recaptured my heart. It was literally a show stopper and I awoke to a standing ovation from the New York theatre audience who were stunned by my modern recreation of the biblical story of Lazarus, or for the more hip among them, my real-life rendition of the resurrection of Jon Snow at the end of season 5 of Game of Thrones.
Against the advice of my doctors, I attended my mom's funeral and again tried to regain some sense of normalcy. We discussed a transplant at this point but, believe it or not, there is such a scarcity of organs I was not yet "sick enough" to get enough priority to receive a heart. I had more surgery to supercharge my ICD so it would be more likely to save my life the next time -- and there would be a next time, I knew.
As a transplant surgeon, I have been involved in some important innovations to expand the number of organs available for transplantation.
Months later in Matera, Italy, where I was attending a medical meeting, I developed what is referred to as ventricular tachycardia storm. I had 4 cardiac arrests over a 3-hour period. With the first one, I fell on to a stone floor and split my forehead open. When I arrived at the small hospital it seemed like Patagonia all over again. One of the first people I met was a Catholic priest who gave me the Last Rights.
I knew now was the moment and so with the help of one of my colleagues who was at the meeting with me and the compassion of the Italian doctors who supplied my friend with resuscitation medications and left my IV in place, I signed out of the hospital against medical advice and boarded a commercial flight back to New York. I was admitted to the NYU intensive care unit and received a heart transplant 3 weeks later.
Now, what I haven't said is that as a transplant surgeon, I have been involved in some important innovations to expand the number of organs available for transplantation. I came to NYU in 2016 to start a new Transplant Institute which included inaugurating a heart transplant program. We hired heart transplant surgeons, cardiologists, and put together a team that unbeknownst to me at the time, would save my life a year later.
It gets even more interesting. One of the innovations that I had been involved in from its inception in the 1990s was using organs from donors at risk for transmitting viruses like HIV and Hepatitis C (Hep C). We popularized new ways to detect these viruses in donors and ensure that the risk was minimized as much as possible so patients in need of a life-saving transplant could utilize these organs.
When the opioid crisis hit hard about four years ago, there were suddenly a lot of potential donors who were IV drug users and 25 percent of them were known to be infected with Hep C (which is spread by needles). In 2018, 49,000 people died in the U.S. from drug overdoses. There were many more donors with Hep C than potential recipients who had previously been exposed to Hep C, and so more than half of these otherwise perfectly good organs were being discarded. At the same time, a new class of drugs was being tested that could cure Hep C.
I was at Johns Hopkins at the time and our team developed a protocol for using these Hep C positive organs for Hep C negative recipients who were willing to take them, even knowing that they were likely to become infected with the virus. We would then treat them after the transplant with this new class of drugs and in all likelihood, cure them. I brought this protocol with me to NYU.
When my own time came, I accepted a Hep C heart from a donor who overdosed on heroin. I became infected with Hep C and it was then eliminated from my body with 2 months of anti-viral therapy. All along this unlikely journey, I was seemingly making decisions that would converge upon that moment in time when I would arise to catch the heart that was meant for me.
Dr. Montgomery with his wife Denyce Graves, September 2019.
(Courtesy Montgomery)
Today, I am almost exactly one year post-transplant, back to work, operating, traveling, enjoying the outdoors, and giving lectures. My heart disease is gone; gone when my heart was removed. Gone also is my ICD. I am no longer at risk for a sudden cardiac death. I traded all that for the life of a transplant patient, which has its own set of challenges, but I clearly traded up. It is cliché, I know, but I enjoy every moment of every day. It is a miracle I am still here.