What to know about this autumn’s covid vaccines

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Last week I came down with some kind of bug. So I got to play one of my least favorite games: “Covid or Not Covid?” In my case, two rapid tests were negative, so probably not covid. But many other people have been testing positive. Covid hospitalizations in the US rose nearly 16% during the third week of August. Even Jill Biden got covid this week. Data suggest we’re at the beginning of a fall wave. And with students returning to schools and workers returning to offices, I’m sure I’m not the only one who is thinking about covid vaccines. It’s been a year since a booster was released, and while the latest wave isn’t likely to be as bad as the tsunami we experienced in 2021-2022, there’s a lot of uncertainty about what the next few months look like. So for this week’s Checkup, let’s take stock of where we’re at. Where are the updated shots? And how do they stack up against the new variants?

When will I be able to get my next covid shot?

Depending on where you live, as soon as this month. At the beginning of the summer, the US Food and Drug Administration decided that the vaccine needed a refresh. The agency advised manufacturers to develop vaccines targeting XBB.1.5, a descendent of omicron and one of the dominant variants circulating at the time. Pfizer, Moderna, and Novavax have done that. Now they’re waiting on FDA approval, and guidance from the Centers for Disease Control and Prevention on how the shots should be administered. That should all happen by mid-September. The CDC’s Advisory Committee on Immunization Practices, the body that provides guidance on who should get vaccinated and when, is set to meet next week, on September 12.  

In Europe, Pfizer’s new vaccine is already approved. The European Commission greenlighted the shot last week. And this week regulators in the United Kingdom followed suit. The first shots should be going into arms soon. Those at greatest risk of developing serious illness in the UK will be eligible for the new shot starting September 11. 

But XBB 1.5 isn’t the only variant circulating these days. How worried should I be about newer ones?

XBB variants are still causing the majority of infections in the US, but a couple of other variants have been gaining ground. According to CDC estimates, EG.5 is now responsible for about 20% of covid-19 cases in the US, more than any other single circulating variant. A variant called FL 1.5.1 comes in second, making up 15% of cases. These viruses don’t seem to cause more severe disease, but they are more adept at evading the body’s immune response.  

Scientists are also paying close attention to a variant first detected in early August known as BA.2.86 or, by its nickname, pirola. This variant is notable because it’s so unlike any of the other versions circulating. “What really caught people’s attention is that it had over 30 mutations in spike, so a very substantial genetic change,” says Dan Barouch, an immunologist at Harvard University, referring to the sharply protruding protein the virus uses to gain entry into cells. It’s only the second time that SARS-CoV2 has made such a big leap. (The first time was the jump from delta to omicron, a shift that led to the deadliest covid wave to date.) The worry is that this massive change in sequence might make the virus harder for our immune systems to recognize and fight off. 

But preliminary data trickling in suggests that fears about pirola may be overblown. In a preprint posted on Tuesday, Barouch and his colleagues looked at blood samples from 66 individuals, some who received the bivalent booster in the fall and some who didn’t. The group also contained a subset of people who had been infected with XBB.1.5 in the past six months. Neutralizing antibody levels against BA.2.86 were comparable or higher than levels against XBB.1.5, EG.5, and FL.1.5.1. So this variant doesn’t seem to be much more immune evasive than other variants. “That was a bit unexpected, and good news,” Barouch says. 

Those results are roughly consistent with what labs in China and Sweden reported in recent days. If you want a fantastic deep dive into all this data, check out this newsletter from Your Local Epidemiologist

BA.2.86 has been “downgraded from a hurricane to not even a tropical storm,” Eric Topol told USA Today, adding, “We’re lucky. This one could have been really bad.” But the data thus far is preliminary. And even if BA.2.86 is just a light rain shower, that  doesn’t mean it won’t lead to problems in the future. “It’s BA.2.86 (Pirola) descendants that worry me more than the current variant per se,” wrote T. Ryan Gregory, an evolutionary biologist at the University of Guelph, on Twitter. “The concern will be that it will continue to evolve and its descendants will have traits that make it successful at reaching new hosts.” In fact, BA.2.86 already has developed a sublineage. 

So if BA 2.86 isn’t causing the surge, what is?

Probably a combination of factors, including waning immunity. The last vaccine update, the bivalent shot, came out a year ago. “It’s been quite a long time since boosters were provided for covid, and those boosters did have a relatively low uptake rate in the population,” noted Johns Hopkins virologist Andrew Pekosz in a recent Q&A. Plus, the new dominant variants are more adept at evading our immune system than previous viruses.

How well will the new vaccines work?  

That remains to be seen. Both Moderna and Pfizer have reported that the new shots elicit a strong antibody response against the XBB variants, as well as EG.5.1, FL 1.5.1, and BA.2.86.

Borouch and his team also found that XBB.1.5 infection appeared to boost neutralizing antibodies against BA.2.86, a hopeful sign that the vaccine might also help fend off the new variant.

But protection will likely fade quickly, just as it did with previous covid vaccines. “We know that the durability of the mRNA boosters is relatively limited,” Barouch says—on the order of six months. 

An updated shot will be most important for people who are immunocompromised or vulnerable in other ways that leave them at high risk for developing severe disease. Whether the shot will be useful for younger, healthier people “is a source of some controversy amongst experts in the field,” Barouch says. 

We know the vaccine won’t protect against any and all covid infections. But it could lessen the severity of the illness. “I still might get [covid], but it just might not be as uncomfortable,” says John Wherry, an immunologist at the University of Pennsylvania. An updated shot might also reduce the risk of developing long covid. “There’s still some chance of getting long Covid every single time you get infected,” Wherry says. But if a robust immune response can keep the virus from spreading beyond the upper respiratory tract, “I think the chances of long covid are probably a little bit lower.”

That’s a win in Wherry’s book: “I’ll take it.”

Read more from Tech Review’s archive

mRNA vaccines came into their own during the covid-19 pandemic, but they can be leveraged for so many other purposes. That includes fighting diseases like malaria and Zika and cancer, wrote Jessica Hamzelou earlier this year. And, as Antonio Regalado reported in 2021, they could also help make gene therapies simpler and cheaper. 

Last year, we introduced you to the scientists tracking the evolution of SARS-CoV-2 and predicting where it might be headed. Linda Nordling has the story

Many companies are working on covid vaccines that you inhale. The hope is that they might provide better protection against infection. Last year, after the first two inhaled vaccines were approved, Jessica Hamelzou provided an explainer.

Could we develop a vaccine against all coronaviruses? (Fingers crossed.) Last year, Adam Piore took a look at some promising developments.  

From around the web:

Last week I wrote about the controversy over new therapies for dwarfism. These medicines help kids grow taller faster, but for many little people, short stature is not a problem in need of a fix. (Nature)

Why does electroconvulsive therapy work? Researchers have shockingly little intel. “‘When I shut down this computer and I reboot it, I turn it back on and it works,’ said Michael Alan Taylor, a retired neuropsychiatrist who studied ECT for years. ‘I know as much about the mechanism of that as I do about ECT. Which is zero.’” (Undark)

Scientists are making headway in the quest to turn stem cells into human embryos. Researchers in Israel have created the most sophisticated and complete version yet, an advance that could lead to better fertility treatments, drug testing, and transplants. (Guardian) 

Could clots explain the brain fog that often comes with long covid? (Scientific American

A cell that does it all

From “The Troubled Hunt for the Ultimate Cell” (1998), by Antonio Regalado: “If awards were given for the most intriguing, controversial, underfunded and hush-hush of scientific pursuits, the search for the human embryonic stem (ES) cell would likely sweep the categories. It’s a hunt for the tabula rasa of human cells—a cell that has the potential to give rise to any of the myriad of cell types found in the body. If this mysterious creature could be captured and grown in the lab, it might change the face of medicine, promising, among other remarkable options, the ability to grow replacement human tissue at will … [but] these cells are found only in embryos or very immature fetuses, and pro-life forces have targeted the researchers who are hunting for ES cells, hoping to stop their science cold. In addition, the federal government has barred federal dollars for human embryo research, pushing it out of the mainstream of developmental biology. To make matters worse, human ES cells could conceivably provide a vehicle for the genetic engineering of people, and the ethical dilemmas surrounding human cloning threaten to spill over onto this field.”

Update from the author (2023): The debate lasted years, but science prevailed over religion in the stem-cell wars of the early 2000s. Now research on ES cells is paid for by the US government. Yet biology keeps offering surprises. The latest? Research shows stem cells in the lab can self-assemble back into “synthetic” embryos, shockingly similar to the real thing. And that’s the next debate.

Tiny faux organs could crack the mystery of menstruation

In the center of the laboratory dish, there was a subtle white film that could only be seen when the light hit the right way. Ayse Nihan Kilinc, a reproductive biologist, popped the dish under the microscope, and an image appeared on the attached screen. As she focused the microscope, the film resolved into clusters of droplet-like spheres with translucent interiors and thin black boundaries. In this magnified view, the structures ranged in size from as small as a quarter to as large as a golf ball. In reality, each was only as big as a few grains of sand.

“They’re growing,” Kilinc said, observing that their plump shapes were a promising sign. “These are good organoids.”

Kilinc, who works in the lab of biological engineer Linda Griffith at MIT, is among a small group of scientists using new tools akin to miniature organs to study a poorly understood—and frequently problematic—part of human physiology: menstruation. Heavy, sometimes debilitating periods strike at least a third of people who menstruate at some point in their lives, causing some to miss weeks of work or school every year and jeopardizing their professional standing. Anemia threatens about two-thirds of people with heavy periods. And when menstrual blood flows through the fallopian tubes and into the body cavity, it’s thought to sometimes create painful lesions—characteristics of a disease called endometriosis, which can require multiple surgeries to control. 

No one is entirely sure how—or why—the human body choreographs this monthly dance of cellular birth, maturation, and death. Many people desperately need treatments to make their period more manageable, but it’s difficult for scientists to design medications without understanding how menstruation really works.

That understanding could be in the works, thanks to endometrial organoids—biomedical tools made from bits of the tissue that lines the uterus, called the endometrium. To make endometrial organoids, scientists collect cells from a human volunteer and let those cells self-organize in laboratory dishes, where they develop into miniature versions of the tissue they came from. The research is still very much in its infancy. But organoids have already provided insights into how endometrial cells communicate and coordinate, and why menstruation is routine for some people and fraught for others. Some researchers are hopeful that these early results mark the dawn of a new era. “I think it’s going to revolutionize the way we think about reproductive health,” says Juan Gnecco, a reproductive engineer at Tufts University. 

An uncommon problem

Periods are rare in the animal kingdom. The human body goes through the menstrual cycle to prepare the uterus to welcome a fetus, whether one is likely to show up or not. In contrast, most animals prepare the uterus only once a fetus is already present. 

That cycle is a constant pattern of wounding and repair. The process starts when levels of a hormone called progesterone plummet, indicating that no baby will be growing in the uterus that month. Removing progesterone triggers a response similar to what happens when the body fights off an infection. Inflammation injures the endometrium. Over the next five or so days, the damaged tissue sloughs off and flows out of the body.

As soon as the bleeding starts, the endometrium begins to heal. Over the course of about 10 days, this tissue quadruples in thickness. No other human tissue is known to grow so extensively and so quickly—“not even aggressive cancer cells,” says Jan Brosens, an obstetrician and gynecologist at the University of Warwick in the UK. As the tissue heals—in a rare example of scarless repair—it becomes an environment that can shield an embryo, which is a foreign entity in the body, from an immune system trained to reject interlopers.

Scientists have filled in the rough outline of this process after decades of research, but many details remain opaque. How exactly the endometrium repairs itself so extensively is unknown. Why some people have much heavier periods than others remains an open question. And why humans menstruate, rather than reabsorbing unused endometrial tissue like many other mammals, is a matter of hot debate among biologists.

This lack of understanding hampers scientists, who would like to find treatments for periods that are too painful to be tamed by over-the-counter painkillers or too heavy to be absorbed by pads and tampons. As a result, many people suffer. A study performed in the Netherlands found that on average women lost about a week of productivity per year because of abdominal pain and other symptoms related to their periods. “It would not be unusual for a patient to see me in the clinic and say that every month, they had to have two or three days off work,” says Hilary Critchley, a gynecologist and reproductive biologist at the University of Edinburgh. 

Heavy periods can make even daily tasks difficult. Getting up from a chair, for example, can be an ordeal for someone worried about the possibility of having stained the seat. Mothers with low iron levels tend to have babies with low birth weights and other health problems, so the effects of heavy menstruation trickle down through generations. And yet the uterus often goes unacknowledged, even by researchers who are exploring topics like tissue regeneration, to which the organ is clearly relevant, Brosens says. “It is almost unforgivable, in my view,” he adds.

Ask researchers why menstruation remains so enigmatic and you’ll get a variety of answers. Most everyone agrees there’s not enough funding to attract the number of researchers the field deserves—as is often the case for health problems that primarily affect women. The fact that menstruation is shrouded in taboos doesn’t help. But some researchers say it has been hard to find the right tools to study the phenomenon.

Scientists tend to start studies of the human body in other organisms, such as mice, fruit flies, and yeast, before translating the knowledge back to humans. These so-called “model systems” reproduce quickly and can be altered genetically, and scientists can work with them without running into as many ethical or logistical concerns as they would if they experimented on people. But because menstruation is so rare in the animal kingdom, it’s been tough to find ways to study the process outside the human body. “I think that the main limitations are model systems, honestly,” says Julie Kim, a reproductive biologist at Northwestern University.

Early adventures

In the 1940s, the Dutch zoologist Cornelius Jan van der Horst was among the first scientists to work on an animal model for studying menstruation. Van der Horst was fascinated by unusual, poorly studied critters, and this fascination led him to South Africa, where he trapped and studied the elephant shrew. With a long snout reminiscent of an elephant’s trunk and a body similar to an opossum’s, the elephant shrew was already an oddball when van der Horst learned that it’s one of the few animals that get a period—a fact he probably discovered “more or less by accident,” says Anthony Carter, a developmental biologist at the University of Southern Denmark who wrote a review of van der Horst’s work.

Elephant shrews are not cooperative study subjects, however. They only menstruate at certain times of year, and they don’t do well in captivity. There’s also the challenge of catching them, which van der Horst and his colleagues attempted with hand-held nets. The shrews were agile, so it was “sometimes a fascinating but mostly a disappointing sport,” he wrote.

Around the same time, George W.D. Hamlett, a Harvard-based biologist, discovered an alternative. Hamlett was examining preserved samples of a nectar-loving bat called Glossophaga soricina when he noticed evidence of menstruation. The bats, which live primarily in Central and South America, were not easily accessible, so for several decades his discovery remained simply a point of interest in the scientific literature. 

Then, in the 1960s, an eager graduate student named John J. Rasweiler IV enrolled at Cornell University. Rasweiler wanted to study a type of animal reproduction that mirrors what happens in humans, so his mentor pointed out Hamlett’s discovery. Perhaps Rasweiler would like to go find some bats and see what he could do with them?

With a long snout reminiscent of an elephant’s trunk and a body similar to an opossum’s, the elephant shrew was already an oddball when van der Horst learned that it’s one of the few animals that get a period.

“It was a very challenging undertaking,” Rasweiler says. “Essentially I had to invent everything from start to finish.” First there were the trips to Trinidad and Colombia to collect the bats. Then there was the issue of how to transport them back to the United States without their getting crushed or overheating. (Shipping them in takeout food containers, bundled together into a larger package, turned out to work well.) Once the bats were in the lab, he had to figure out how to work with them without letting them escape. He ended up constructing a walk-in cage on wheels that he could roll up to the bats’ enclosures.

“I loved working with them—delightful animals,” says Rasweiler, who has since retired from a career as a reproductive physiologist at SUNY Downstate. But other researchers were put off by the idea of working with a flying animal. 

Researchers can track how organoids respond to various stimuli. Here endometrial tissue thickens when exposed to a synthetic version of the hormone progesterone, mirroring the lead-up to menstruation. Image source: “Organoid co-culture model of the cycling human endometrium in a fully-defined synthetic 2 extracellular matrix reveals epithelial-stromal crosstalk.” Juan S. Gnecco et al.

In 2016, the spiny mouse—a rodent that thrives in the dry conditions of the Middle East, South Asia, and parts of Africa—joined the exclusive club of animals known to menstruate. Spiny mice can be raised in the lab, so they may become valuable subjects for menstruation research. But millions of years of evolution lie between humans and mice, leading Brosens to think the genetics underlying their uteruses are likely to differ substantially.

Much of the foundational work on menstruation has been performed in macaque monkeys. But primates are expensive to care for, and the Animal Welfare Act places restrictions on primate research that do not apply to other common lab animals. Through a series of manipulations, scientists also found that they could force a common lab mouse to have something similar to a period. This model has been useful, but it’s still only an artificial representation of true human menstruation.

What researchers really needed was a way to use humans as study subjects for menstruation research. But even setting aside the obvious ethical concerns, such a thing would be very challenging logistically. The endometrium evolves exceedingly quickly—“at an hourly rate, we see different responses from the cells, different functions,” says Aleksandra Tsolova, a cell biologist at the University of Calgary. “It’s very dynamic tissue.” Researchers would need to perform invasive biopsies almost constantly to study it inside the human body, and even then, altering it genetically or through chemical treatments would be largely impossible.

But by the early 1900s, a solution to this problem had already started to emerge. And it was not a creature from the jungle or the African grasslands that paved the road, but an organism from the bottom of the sea.

Organoids come on the scene

The groundwork for what would become modern-day organoids was laid in 1910, when a zoologist named Henry Van Peters Wilson realized that cells from marine sponges have a sort of “memory” of how they’re arranged in the animal, even after they’re separated. When he dissociated a sponge by squeezing it through a mesh and then mixed the cells together again, the original sponge re-formed. Midcentury work showed that certain cells from chick embryos have a similar ability.

In 2009, a study published in the journal Naturedescribed a possible way of extending these observations to human organs. The researchers took a single adult stem cell from a mouse intestine—which had the ability to become any type of intestinal cell—and embedded it in a gelatinous substance. The cell divided and, together with its progeny, formed a miniature, simplified version of the intestinal lining. It was the first time scientists had laid out a method of creating an organoid from human tissue that was accessible to many labs and straightforward to adapt to other organs. 

Since then, scientists have extended this general approach to mimic aspects of around a dozen human tissue types, including those from the gut, the kidneys, and the brain—and, by the late 2010s, the uterus. 

It was a happy accident that brought endometrial organoids into the mix. In the years leading up to their development, scientists had been trying to study the endometrium by growing its cells in smooth layers on the bottoms of laboratory dishes. Stromal cells, which provide structural support for the tissue and play a key role in pregnancy, proved easy to grow this way—these cells secrete a substance that sticks them to each other, and also makes them adhere to petri dishes. But epithelial cells, another critical component of the endometrium, posed a problem. In a dish, they stopped responding to hormones, and their shapes were unlike what’s seen in the human body.

Then, while working with a mix of human placental and endometrial tissue in an effort to get the placenta to form organoids, a reproductive biologist named Margherita Turco noticed something serendipitous. If they were suspended in a gel instead of being grown in liquid, and given just the right mix of molecules from the human body, endometrial epithelial cells assembled into tiny three-dimensional simulacra of the organ they came from. “They grew really, really well,” Turco says. In fact, endometrial organoids were “kind of overtaking the cultures.” Another group independently published similar findings around the same time.

Today, placental and endometrial organoids are both valuable tools in the lab Turco runs at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland. Her original 2017 publication calls for using tissue from a biopsy, rather than stem cells, to make organoids from the endometrium. Some labs instead use tissue removed from people who have had hysterectomies. But Turco’s lab recently showed that bits of the endometrium found in menstrual blood also work, which would mean the new endometrial organoids can be grown without requiring biopsies or surgery.

From all these starting points, researchers can now create microcosms of the human uterus. Each organoid reminds Tsolova of a tiny bubble suspended in a gelatinous dessert. And each presents a unique opportunity to understand processes that science has long ignored.

Period in a dish

Endometrial organoids became integral to the work of the small community of researchers focused on the uterus. Since 2017, many labs have put their own spins on these new tools.

Kim’s lab has added stromal cells to the epithelial cells that make up classic endometrial organoids. She and her colleagues mix the two together and simply let the combination “do its thing,” she says. The result is like a malt ball with stromal cells on the inside and epithelial cells on the outside. 

In 2021, Brosens and his colleagues created similar structures, which they call “assembloids.” Instead of mixing the two cell types together, they created an organoid out of epithelial cells and then added a layer of stromal cells on top. Using assembloids, they’ve learned that deteriorating cells play a key role in helping the embryo implant in the uterus. Because the endometrium is constantly dying and regrowing, the tissue is highly flexible and able to adjust its shape, Brosens explains. This helps the tissue kick-start pregnancy: “Maternal cells will grab the embryo,” he says, “and literally pull that embryo into the tissue.” 

A video from one of Brosens’s recent publications shows an assembloid remodeling around a five-day-old embryo. Before he and his colleagues did this work, conventional wisdom said the endometrium was passive tissue that was invaded by the embryo, but that’s “just completely wrong,” he says. This new understanding of how embryos implant could improve in vitro fertilization and help explain why some people are prone to miscarriages. 

Margherita Turco’s laboratory at the Friedrich Miescher Institute for Biomedical Research in Switzerland has found that organoids derived directly from the endometrium (first image) and from menstrual blood (second image) of the same person have indistinguishable shapes and structures. Image source: “Menstrual flow as a non-invasive source of endometrial organoids.” Tereza Cindrova-Davies et al. communications biology.

Eventually, Critchley hopes, scientists can design treatments that let people choose when to have a period—or if they even want to have one at all. Hormonal birth control can accomplish these goals for some, but these drugs can also cause unscheduled bleeding that makes periods harder to manage, and some people find the side effects of the medication intolerable. 

To create better options, scientists still need to understand how a normal period works. Making an organoid menstruate in a dish would be a huge boon for achieving this goal, so that’s what some researchers are trying to do.

By manually adding hormones to organoids, Gnecco and his collaborators can replicate some of what the endometrium experiences over the course of a month. As the cycle progresses, they see the cells adjusting the complement of genes they use, just as they would in the human body. The shape of the organoid also follows a familiar pattern. Glands—infoldings of cells from which mucus and other substances are secreted—change from smooth tubes to sawtooth-like structures as this faux menstrual cycle progresses.

“It’s mind-blowing that we are very, very close to the patient, but we’re not working within the patient. There’s huge potential.”

Aleksandra Tsolova, cell biologist, University of Calgary

With this system working, the next step is to figure out what happens when the endometrium malfunctions. “That’s what really got me excited,” Gnecco says. As a first step, he treated organoids with an inflammatory molecule called IL-1β, which is a hallmark of the lesions that characterize endometriosis. IL-1β caused organoids to grow rapidly, but only when stromal cells were mixed in along with the epithelial cells. This suggests that signals from stromal cells might be part of what causes endometriosis to develop into a painful condition.

Meanwhile, Kilinc is trying to understand why some people’s periods are so heavy. Endometrial tissue growing into the muscle that lines the uterus seems to cause lesions, which can be one source of excessive bleeding. To see how such lesions could form, Kilinc watches how endometrial organoids react when they hit a dense gel, which mimics the texture of muscle.

In a soft gel, endometrial organoids maintain a nice, round structure. But when the organoid is in a stiff gel, it’s a different story. A video from one of Kilinc’s recent experiments shows an organoid pulsating and squirming, almost like a pot of water that’s about to boil over. Finally, a group of cells shoots off, creating an appendage-­like structure that punctures the stiff gel. Videos like this make Kilinc think that contact with muscle might be among the triggers that cause the endometrium to start wounding this tissue and causing heavy bleeding. “But,” she adds, “this is not clear yet—we are still investigating.”

Speedier science

Today’s endometrial organoids can’t do everything animal models can do. For one thing, they don’t yet include key components of menstruation, like blood vessels and immune cells. For another, they can’t reveal how distant parts of the body, like the brain, influence what happens in the uterus. But because they’re derived from human tissue, they’re intimately related to the bizarre, idiosyncratic process that is a human period, and that’s worth a lot. “It’s mind-blowing that we are very, very close to the patient, but we’re not working within the patient,” Tsolova says. “There’s huge potential.”

In parallel to the work on organoids, scientists have created an “organ on a chip” that mimics the endometrium. Tiny tubes affixed to a flat surface carry liquids to endometrial tissue, mimicking the flow of blood or hormones transmitted from other parts of the body. An ideal model system could combine endometrial cells in their natural arrangement—as in an organoid—with flowing liquids, as on a chip.

Already, organoids have helped researchers solve old puzzles. Researchers in Vienna, for example, used this technology to figure out which genes cause some endometrial cells to grow cilia—hair-like structures that beat in coordination to move liquid, mucus, and embryos within the uterus. Other researchers have used organoids to learn how endometrial cells mature throughout the menstrual cycle. Meanwhile, Kim and her colleagues used organoids to study how the endometrium responds to abnormal hormone levels, which may be a factor in endometrial cancer.

People who menstruate have waited a long time for researchers to tackle such questions. Burdensome periods are often seen as just a “women’s problem”—a mindset Tsolova disagrees with because it ignores the fact that people struggling with menstruation often can’t contribute their full range of talents to their communities. “It’s a societal problem,” she says. “It affects every person, in every way.” 

Saima Sidik is a freelance science journalist based in Somerville, Massachusetts.

A chemo drug shortage shows the vulnerability of the healthcare supply chains

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

If you’ve been following health headlines in recent months, you may have heard that many prescription drugs are in short supply. Yesterday, the New York Times ran a piece about the scarcity of ADHD medicines. Certain steroids have also been hard to find. But many of the headlines that caught my eye have focused on the lack of common chemotherapy drugs. For cancer patients, shortages could mean the difference between life and death.

Last week, the American Society of Health-System Pharmacists (ASHP) released the results of a member survey to assess the severity of these shortages. Drug shortages are nothing new, but results from more than 1,000 pharmacists suggest that the current crisis is particularly concerning. More than 99% of respondents, nearly all of them pharmacists who work for hospitals or health systems, reported that they were facing drug shortages. In some cases, shortages are annoying but manageable.

“We’re talking about things that we can easily substitute for something else. Or we can provide a different dosage or a different route of administration,” says Michael Ganio, senior director of Pharmacy Practice and Quality at ASHP. But in this latest survey, nearly a third of respondents said that current shortages had forced their hospital to ration, delay, or cancel treatments or procedures. “That’s significant,” he adds.  

The current cancer drug crisis stems from an incident last fall. Many of the pharmaceuticals sold in the US are manufactured overseas. In November, the Food and Drug Administration toured one of those plants in India, a facility owned by Intas Pharmaceuticals. Inspectors observed numerous violations related to quality control and data integrity. As a result, the plant halted production. It was the first domino to fall in a chain that would lead to a nationwide shortage of cancer therapy drugs..

Before the shutdown, Intas produced about 50% of US’s supply of  cisplatin, a common cancer drug used to treat  testicular, ovarian, bladder, head and neck, lung, and cervical cancers. When the plant halted production, other manufacturers weren’t able to ramp up enough to avoid a shortfall. Manufacturers don’t have that kind of surge capacity. If a company consistently produces 10% of the market share, “what is their incentive to have capacity to produce 30 or 40%?” says Mariana Socal, a health policy researcher at the Johns Hopkins Bloomberg School of Public Health.

As cisplatin became scarce, oncologists switched to carboplatin, another common cancer therapy, which Intas also produced. With Intas no longer producing carboplatin and increasing demand, that medicine is now also in short supply. It was “like a ripple effect in the supply chain,” Socal says.

A survey of US cancer centers in May revealed that a whopping 93% were experiencing shortages of carboplatin. 

The impact on patients has been profound. Some have gotten smaller doses. Others have had to skip or delay treatments. Some medical organizations are advising doctors to reserve cisplatin and carboplatin for patients who have a chance at a cure.

“This shortage will lead to people dying,” Ravi Rao, an oncologist at a cancer center in Fresno, California, told the New York Times. “There’s just no way around it. You cannot remove these lifesaving drugs and not have bad outcomes.”

Even if Intas comes back on line and the shortage eases, the system will still be vulnerable. Socal likens the drug manufacturing system to a person with a chronic illness. Flare-ups may come and go, but we “still have that chronic condition underlying all of our supply chain.”

Generic drugs are especially vulnerable to shortages because profits are so slim. Cisplatin and carboplatin both cost less than $25 a vial. “The free market is pushing for this race to the bottom,” Socal says. When prices—and therefore profits—are so low, manufacturers don’t have any incentive to invest in improving manufacturing practices for these drugs, which might include upgrading equipment, expanding capacity, and creating redundancies.

The same typically isn’t true for name-brand medications, which are still under patent and thus produced by a single company. “There’s  a lot of economic incentive to keep those production lines up and running.” Ganio says.

There are ways to blunt the impact of shortages. Better planning could help. Currently, drug shortages happen with very little warning and the market is forced to react. But AI could provide an early warning system for drug shortages to help manufacturers and pharmacies plan ahead. One supply chain management company, TraceLink, has developed a product designed to do just that. The tool uses real-time data from the supply chain to predict drug shortages and their duration. According to TraceLink, the system can provide predictions up to 90 days in advance with greater than 80% accuracy. Things like the Intas shutdown, however, might be difficult to predict. When FDA inspectors record violations, the agency doesn’t always make the findings publicly available in a timely manner, Ganio says. “An FDA inspection report or warning letter often lags by several months.” 

Advanced manufacturing tech could also help curb shortages. That might include things like 3D printing of drugs, automated monitoring to identify equipment that might not be working properly, and continuous manufacturing rather than batch production, which is more efficient, but expensive to implement, Ganio says. 

But these tech fixes won’t address the root of the problem. Generic manufacturers need more incentives to focus on quality, not just cost. “The only information that is [currently] available to anyone in the supply chain is the price,”  Socal says. If drug purchasers had a metric related to quality—for example, higher grades for manufacturers that have never had quality issues, and lower grades for plants that have had manufacturing violations—they could incorporate that into their purchasing decisions. That might be something the FDA could help implement. The agency has been trying for years, in fact. Or purchasers themselves could require that companies disclose their ratings in their contracts. 

None of the proposed fixes will be easy or simple, but they’re urgently needed. “Lives are at stake,” Socal says. “Public health in America is really depending on a working and dependable drug supply chain.”

Read more from Tech Review’s archive

Portable manufacturing systems could provide on demand meds in the event of a shortage, like a backup generator for the pharmaceutical industry, Mike Orcutt reported in 2016.

Back in 2013, Karen Weintraub wrote about the race between two Biotech giants to invent new ways to manufacture biological drugs

Can AI help pharma develop better drugs? Will Douglas Heaven has the story from earlier this year. (He also wrote about the quest to use AI in biotech in December 2022.)  

From around the web

After the death of a clinical trial participant by suicide, regulators suspended  human research at The New York State Psychiatric Institute, and the lead researcher, a Columbia professor, resigned. Here’s what might have gone wrong.  (New York Times

A new study finds that older adults who were hospitalized for Covid have twice the risk of death in the month after discharge as older adults who were hospitalized because of the flu. But it’s not clear whether that’s due to the nature of the viruses or to differences in immunity. (CIDRAP)

More than half of people who need medication for addiction aren’t getting it. (New York Times)

Covid hospitalizations are on the rise again. Sigh. (US News)

The  Smithsonian has a collection of more than 30,000 human body parts, many of them taken without consent from Black and indigenous people. Why haven’t they returned them?  (Washington Post

Why is it so hard to create new types of pain relievers?

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

This week I’ve been thinking about America’s addiction to opioids. The statistics are staggering. Since 2010, opioid overdose deaths have nearly quadrupled. More than 80,000 people died from an opioid overdose last year. That’s one death every six and a half minutes.

Opioid use disorder is a particularly difficult disease to treat. But we do have safe and effective medications. These drugs help curb withdrawal symptoms, reduce illegal opioid use, and help people stay in treatment. They also reduce the risk of death from overdose. A study published Monday, however, shows that just one in five people with opioid use disorder receives these drugs.

Clearly, we need to do better. That means improving treatment, but it also means finding alternative methods for controlling pain, a task that has proved exceedingly difficult. A study published last week suggests the Boston-based biotech Vertex may be making headway with its compound VX-548, a pill that aims to relieve pain in the wake of surgery. The highest dose of the compound offered greater pain relief than a placebo after bunion removal or tummy tuck surgery. That’s good news in a space that has had more than its fair share of setbacks.

Treating pain is complicated because pain itself is complicated. Doctors categorize pain by how long it lasts—acute vs. chronic—and also how it begins. Some pain starts with damage to the body—a cut, a burn, a broken arm, a tumor. Sensory nerves (neurons) in our body detect the damage and send pain signals to the brain. Some pain, such as the stinging and burning that comes with diabetic nerve damage, begins with injury to the neurons themselves.

Opioids—heroin, morphine, fentanyl and all the rest—work by masking pain. They bind to receptors in the brain and spinal cord, initiating a series of reactions that help block pain signals. Prescription opioids are extremely good at pain relief in certain situations. But they don’t just block pain. Activating the opioid receptors also prompts a rush of dopamine, which makes us feel good—even euphoric. The feeling doesn’t last. And the more a person takes, the more is needed to get the same rush. That’s why these drugs are ripe for abuse. 

Non-opioid painkillers already exist, of course—things like ibuprofen, aspirin, acetaminophen, and naproxen sodium. You’re probably familiar with many of them because they’re available over the counter. They don’t trigger a dopamine release and aren’t addictive like opioids, but these medications come with some serious drawbacks: ulcers, bleeding, heart problems, and more. Most (with the exception of acetaminophen) belong to a class called nonsteroidal anti-inflammatory drugs, or NSAIDS for short. As the name suggests, they target inflammation in the body, blocking the production of chemicals that cause us to feel pain. But they don’t work for pain of many other types.

The effort to develop new classes of pain medicines has hit many roadblocks. Just last year Regenron pulled the plug on development of a compound to treat osteoarthritis and chronic back pain; an experimental pain therapy from the Illinois-based biotech Aptinyx failed in a trial to help people with fibromyalgia; and the California company Acadia reported that its compound performed no better than a placebo in people who had undergone bunion removal surgery*.  In 2021, Eli Lilly and Pfizer halted development of  tanezumab, a monoclonal antibody to treat pain in people with osteoarthritis. Why each of these failures occurred isn’t entirely clear, which makes it difficult to find the best path forward.

Vertex’s new compound is part of a class of drugs that target sodium channels on the pain-sensing nerves themselves. Stephen Waxman, a Yale neurologist who studies pain, describes them as “tiny molecular batteries” that drive the production of nerve impulses. Some sodium channel blockers already exist—the numbing agent lidocaine, for example. But because they block all sodium channels, even crucial ones on heart cells and in the brain, they are often administered only as local anesthetics.

VX-548 targets a specific channel called Nav1.8 that is found only on pain-sensing neurons. That means it can work broadly on those neurons throughout the body without blocking the function of the heart or brain. Because it doesn’t activate opioid receptors, it also doesn’t trigger a release of dopamine, giving people pain relief without an accompanying high. 

Phase 2 trials of the drug enrolled people with moderate to severe pain following a tummy tuck or bunion removal. Patients who requested pain medication were randomized to one of several groups. Some participants received VX-548 at one of three dosage levels, some got a placebo pill, and some took a pill that contained hydrocodone (an opioid). Those taking the highest dose of VX-548 experienced greater reductions in pain than those in the other groups.

An editorial accompanying the study noted that the effect was “small.” But the results are exciting, in part because the hunt for non-opioid painkillers has had so few successes of any size. “Here we have a clinical study in humans that shows that you can target one of these peripheral sodium channels and reduce pain in human subjects without adverse side effects,” Waxman told the New England Journal of Medicine. “I see us at the first stage in humans of a new generation of pain medications.” 

We can hope. 

*You might wonder, as my editor did, why so many pain medicine trials include patients undergoing bunionectomies. It’s one of the classic surgical models of acute pain. Dental extraction is another. The more you know.

Read more from Tech Review’s archive

Adam Piore wrote about the quest to develop nonaddictive painkillers way back in 2016. 

Could an ingestible capsule keep tabs on whether patients are taking too many prescription opioids? Emily Mullin covered this new technology in 2017. 

Neuroscientist Fan Wang is looking for the brain circuits that control pain. Georgina Gustin profiled Wang and her work in 2021. 

Recorded brain waves can help quantify pain, which could upend some types of treatment, Rhiannon Williams reported in May

Another thing: 

Twenty-five years have passed since researchers isolated the first embryonic stem cells, but we’re still waiting for stem-cell therapies. Antonio Regalado looks at the hype and the hope. 

Who gets access to experimental treatments—especially some of the ultra-novel treatments that are just beginning to emerge? Jessica Hamezlou dives into this thorny ethical question in a story for MIT Technology Review’s ethics issue. 

From around the web:

Data from a landmark study show that the obesity drug Wegovy slashed the risk of heart attacks, strokes, and cardiovascular deaths by 20%, according to the drug’s maker. (The New York Times)

This week the FDA approved the very first therapy exclusively for postpartum depression. (Stat News)

The US has a new covid variant. Meet Eris. (Washington Post)

And if you want more about the opioid crisis, the podcast Serial has a new season out called  The Retrievals, which offers a devastating case study on how opioid abuse can affect patients. The series is about a nurse who stole fentanyl vials and replaced the contents with saline, and the women who underwent egg retrievals without fentanyl as a result. It’s horrifying, but very much worth your time.

Who gets to decide who receives experimental medical treatments?

Max was only a toddler when his parents noticed there was “something different” about the way he moved. He was slower than other kids his age, and he struggled to jump. He couldn’t run. 

Blood tests suggested he might have a genetic disease— one that affected a key muscle protein. Max’s dad, Tao Wang, a researcher for a climate philanthropy organization, says he and his wife were initially in denial. It took them a few months to take Max for the genetic test that confirmed their fears: he had Duchenne muscular dystrophy.

Duchenne is a rare disease that tends to affect young boys. It’s progressive—those affected generally lose muscle function as they get older. There is no cure. Many people with the disorder require wheelchairs by the time they reach their 20s. Most do not survive beyond their 30s. 

Max’s diagnosis hit Wang and his wife “like a tornado,” he says. But eventually one of his doctors mentioned a clinical trial that he was eligible for. The trial was for an experimental gene therapy designed to replace the missing muscle protein with a shortened, engineered version that might help slow his decline or even reverse it. Enrolling Max in the trial was a no-brainer for Wang. “We were willing to try anything that could change the course [of the disease] and give us some hope,” he says. 

That was more than two years ago. Today, Max is an active eight-year-old, says Wang. He runs, jumps, climbs stairs without difficulty, and even enjoys hiking. “He’s a totally different kid,” says Wang. 

The gene therapy he received was recently considered for accelerated approval by the US Food and Drug Administration. Such approvals, reserved for therapies targeting serious conditions that lack existing treatments, require less clinical trial data than standard approvals. 

While the process can work well, it doesn’t always. And in this case, the data is not particularly compelling. The drug failed a randomized clinical trial—it was found to be no better than a placebo. 

Still, many affected by Duchenne are clamoring for access to the treatment. At an FDA advisory committee meeting in May set up to evaluate its merits, multiple parents of children with Duchenne pleaded with the organization to approve the drug immediately—months before the results of another clinical trial were due. On June 22, the FDA granted conditional approval for the drug for four- and five-year-old boys.

This drug isn’t the only one to have been approved on weak evidence. There has been a trend toward lowering the bar for new medicines, and it is becoming easier for people to access treatments that might not help them—and could harm them. Anecdotes appear to be overpowering evidence in decisions on drug approval. As a result, we’re ending up with some drugs that don’t work. 

We urgently need to question how these decisions are made. Who should have access to experimental therapies? And who should get to decide? Such questions are especially pressing considering how quickly biotechnology is advancing. Recent years have seen an explosion in what scientists call “ultra-novel” therapies, many of which involve gene editing. We’re not just improving on existing classes of treatments—we’re creating entirely new ones. Managing access to them will be tricky.

Just last year, a woman received a CRISPR treatment designed to lower her levels of cholesterol—a therapy that directly edited her genetic code. Also last year, a genetically modified pig’s heart was transplanted into a man with severe heart disease. Debates have raged over whether he was the right candidate for the surgery, since he ultimately died.

For many, especially those with severe diseases, trying an experimental treatment may be better than nothing. That’s the case for some people with Duchenne, says Hawken Miller, a 26-year-old with the condition. “It’s a fatal disease,” he says. “Some people would rather do something than sit around and wait for it to take their lives.”

Expanding access

There’s a difficult balance to be reached between protecting people from the unknown effects of a new treatment and enabling access to something potentially life-saving. Trying an experimental drug could cure a person’s disease. It could also end up making no difference, or even doing harm. And if companies struggle to get funding following a bad outcome, it could delay progress in an entire research field—perhaps slowing future drug approvals. 

In the US, most experimental treatments are accessed through the FDA. Starting in the 1960s and ’70s, drug manufacturers had to prove to the agency that their products actually worked, and that the benefits of taking them would outweigh any risks. “That really closed the door on patients’ being able to access drugs on a speculative basis,” says Christopher Robertson, a specialist in health law at Boston University.

It makes sense to set a high bar of evidence for new medicines. But the way you weigh risks and benefits can change when you receive a devastating diagnosis. And it wasn’t long before people with terminal illnesses started asking for access to unapproved, experimental drugs.

“If … somebody gets compassionate use and then something bad happens to them, investors run away. It’s a business risk.”

Alison Bateman-House, ethicist

In 1979, a group of people with terminal cancer and their spouses brought a legal case against the government to allow them to access an experimental treatment. While a district court ruled that one of the plaintiffs should be allowed to buy the drug, it concluded that whether a person’s disease was curable or not was beside the point—everyone should still be protected from ineffective drugs. The decision was eventually backed by the Supreme Court. “Even for terminally ill patients, there’s still a concept of safety and efficacy under the statute,” says Robertson.

Today, there are lots of ways people might access experimental drugs on an individual basis. Perhaps the most obvious way is by taking part in a clinical trial. Early-stage trials typically offer low doses to healthy volunteers to make sure new drugs are safe before they are offered to people with the condition the drugs are ultimately meant to treat. Some trials are “open label,” where everyone knows who is getting what. The gold standard is trials that are randomized, placebo controlled, and blinded: some volunteers get the drug, some get the placebo, and no one—not even the doctors administering the drugs—knows who is getting what until after the results have been collected. These are the kinds of studies you need to do to tell if a drug is really going to help people.

But clinical trials aren’t an option for everyone who might want to try an unproven treatment. Trials tend to have strict criteria about who is eligible depending on their age and health status, for example. Geography and timing matter, too—a person who wants to try a certain drug might live too far from where the trial is being conducted, or might have missed the enrollment window.

Instead, such people can apply to the FDA under the organization’s expanded access program, also known as “compassionate use.” The FDA approves almost all such requests. It then comes down to the drug manufacturer to decide whether to sell the person the drug at cost (it is not allowed to make a profit), offer it for free, or deny the request altogether. 

Another option is to make a request under the Right to Try Act. The law, passed in 2018, establishes a new route for people with life-threatening conditions to access experimental drugs—one that bypasses the FDA. Its introduction was viewed by many as a political stunt, given that the FDA has rarely been the barrier to getting hold of such medicines. Under Right to Try, companies still have the choice of whether or not to provide the drug to a patient. 

When a patient is denied access through one of these pathways, it can make headlines. “It’s almost always the same story,” says Alison Bateman-House, an ethicist who researches access to investigational medical products at New York University’s Grossman School of Medicine. In this story, someone is fighting for access to a drug and being denied it by “cold and heartless” pharma or the FDA, she says. The story is always about “patients valiantly struggling for something that would undoubtedly help them if they could just get to it.” 

But in reality, things aren’t quite so simple. When companies decide not to offer someone a drug, you can’t really blame them for making that decision, says Bateman-House. After all, the people making such requests are usually incredibly ill. If someone were to die after taking that drug, not only would it look bad, but it could also put off investors from funding further development. “If you have a case in the media where somebody gets compassionate use and then something bad happens to them, investors run away,” says Bateman-House. “It’s a business risk.”

FDA approval of a drug means it can be sold and prescribed—crucially, it’s no longer experimental. Which is why many see approval as the best way to get hold of a promising new treatment. 

As part of a standard approval process, which should take 10 months or less, the FDA will ask to see clinical trial evidence that the drug is both safe and effective. Collecting this kind of evidence can be a long and expensive process. But there are shortcuts for desperate situations, such as the outbreak of covid-19 or rare and fatal diseases—and for serious diseases with few treatment options, like Duchenne.

Anecdotes vs. evidence 

Max accessed his drug through a clinical trial. The treatment, then called SRP-9001, was developed by the pharmaceutical company Sarepta and is designed to replace dystrophin, the protein missing in children with Duchenne muscular dystrophy. The protein is thought to protect muscle cells from damage when the muscles contract. Without it, muscles become damaged and start to degenerate.

The dystrophin protein has a huge genetic sequence—it’s too long for the entire thing to fit into a virus, the usual means of delivering new genetic material into a person’s body. So the team at Sarepta designed a shorter version, which they call micro-dystrophin. The code for the protein is delivered by means of a single intravenous infusion. 

The company’s initial goal was to develop it as a therapy for children between four and seven with a diagnosis of Duchenne. And it had a way to potentially fast-track the process. 

Usually, before a drug can be approved, it will go through several clinical trials. But accelerated approval offers a shortcut for companies that can show that their drug is desperately needed, safe, and supported by compelling preliminary evidence. 

Max Wang riding a bicycle
More than two years after participating in a clinical trial testing a treatment for Duchenne muscular dystrophy, Max Wang is an active eight-year-old. However, the drug being studied, Sarepta’s SRP-9001, failed to perform better than placebo across the whole group of boys in the trial.
COURTESY OF TAO WANG

For this kind of approval, drug companies don’t need to show that a treatment has improved anyone’s health—they just need to show improvement in some biomarker related to the disease (in Sarepta’s case, the levels of the micro-dystrophin protein in people’s blood).

There’s an important proviso: the company must promise to continue studying the drug, and to provide “confirmatory trial evidence.”

This process can work well. But in recent years, it has been a “disaster,” says Diana Zuckerman, president of the National Center for Health Research, a nonprofit that assesses research on health issues. Zuckerman believes the bar of evidence for accelerated approval has been dropping. 

Many drugs approved via this process are later found ineffective. Some have even been shown to leave people worse off. For example, between 2009 and 2022, 48 cancer drugs received accelerated approval to treat 66 conditions—and 15 of those approvals have since been withdrawn

Melfulfen was one of these. The drug was granted accelerated approval for multiple myeloma in February 2021. Just five months later, the FDA issued an alert following the release of trial results suggesting that people taking the drug had a higher risk of death. In October 2021, the company that made the drug announced it was to be taken off the market.

There are other examples. Take Makena, a treatment meant to reduce the risk of preterm birth. The drug was granted accelerated approval in 2011 on the basis of results from a small trial. Larger, later studies suggested it didn’t work after all. Earlier this year, the FDA withdrew approval for the drug. But it had already been prescribed to hundreds of thousands of people—nearly 310,000 women were given the drug between 2011 and 2020 alone.

And then there’s Aduhelm. The drug was developed as a treatment for Alzheimer’s disease. When trial data was presented to an FDA advisory committee, 10 of 11 panel members voted against approval. The 11th was uncertain. There was no convincing evidence that the drug slowed cognitive decline, the majority of the members found. “There was not any real evidence that this drug was going to help patients,” says Zuckerman.

Despite that, the FDA gave Aduhelm accelerated approval in 2021. The drug went on the market at a price of $56,000 a year. Three of the committee members resigned in response to the FDA’s approval. And in April 2022, the Centers for Medicare & Medicaid Services announced that Medicare would only cover treatment that was administered as part of a clinical trial. The case demonstrates that accelerated approval is no guarantee a drug will become easier to access.

The other important issue is cost. Before a drug is approved, people might be able to get it through expanded access—usually for free. But once the drug is approved, many people who want it will have to pay. And new treatments—especially gene therapies—don’t tend to be cheap. We’re talking hundreds of thousands, or even millions, of dollars. “No patient or families should have to pay for a drug that’s not proven to work,” says Zuckerman.

What about SRP-9001? On May 12, the FDA held an advisory committee meeting to assess whether the data supported accelerated approval. During the nine-hour virtual meeting, scientists, doctors, statisticians, ethicists, and patient advocates presented the data collected so far, and shared their opinions.

Sarepta had results from three clinical trials of the drug in boys with Duchenne. Only one of the three—involving 41 volunteers aged four to seven—was randomized, blinded, and placebo controlled.

Scientists will tell you that’s the only study you can draw conclusions from. And unfortunately, that trial did not go particularly well—by the end of 48 weeks, the children who got the drug were not doing any better than those who got a placebo.

But videos presented by parents whose children had taken the drug told a different story.

Take the footage shared by Brent Furbee. In a video clip taken before he got the gene therapy, Furbee’s son Emerson is obviously struggling to get up the stairs. He slowly swings one leg around while clinging to the banister, before dragging his other leg up behind him. 

A second video, taken after the treatment, shows him taking the stairs one foot at a time, with the speed you’d expect of a healthy four-year-old. In a third, he is happily pedaling away on his tricycle. Furbee told the committee that Emerson, now six, could run faster, get up more quickly, and perform better on tests of strength and agility. “Emerson continues to get stronger,” he said.

It was one of many powerful, moving testimonies—and these stories appear to have influenced the FDA’s voting committee, despite many concerns raised about the drug. 

The idea of providing the genetic code for the body to make a shortened version of dystrophin is based on evidence that people who have similarly short proteins have a much milder form of muscular dystrophy than those whose bodies produce little to no dystrophin. But it’s uncertain whether Sarepta’s protein, with its missing regions, will function in the same way.

Louise Rodino-Klapac, executive vice president, chief scientific officer, and head of R&D at Sarepta, defends the drug: “The totality of the evidence is what gives us great confidence in the therapy.” She has an explanation for why the placebo-controlled trial didn’t show a benefit overall. The groups of six- to seven-year-olds receiving the drug and the placebo were poorly matched “at baseline,” she says. She also says that the researchers saw a statistically significant result when they focused only on the four- and five-year-olds studied. 

But the difference is not statistically significant for the results the trial was designed to collect. And there are some safety concerns. While most of the boys developed only “mild” side effects, like vomiting, nausea, and fever, a few experienced more serious, although temporary, problems. There were a total of nine serious complications among the 85 volunteers. One boy had heart inflammation. Another developed an immune disease that damages muscle fibers.

On top of all that, as things currently stand, receiving one gene therapy limits future gene therapy options. That’s because the virus used to deliver the therapy causes the body to mount an immune response. Many gene therapies rely on a type called adeno-associated virus, or AAV. If a more effective gene therapy that uses the same virus comes along in the coming years, those who have taken this drug won’t be able to take the newer treatment.

Despite all this, the committee voted 8–6 in favor of granting the drug an accelerated approval. Many committee members highlighted the impact of the stories and videos shared by parents like Brent Furbee.

“Now, I don’t know whether those boys got placebo or whether they got the drug, but I suspect that they got the drug,” a neurologist named Anthony Amato told the audience.

“Those videos, anecdotal as they are … are substantial evidence of effectiveness,” said committee member Donald B. Kohn, a stem-cell biologist.

The drugs don’t work?

Powerful as they are, individual experiences are just that. “If you look at the evidentiary hierarchy, anecdote is considered the lowest level of evidence,” says Bateman-House. “It’s certainly nowhere near clinical-trial-level evidence.”

This is not the way we should be approving drugs, says Zuckerman. And it’s not the first time Sarepta has had a drug approved on the basis of weak evidence, either. 

The company has already received FDA approval to sell three other drugs for Duchenne, all of them designed to skip over faulty exons—bits of DNA that code for a protein. Such drugs should allow cells to make a longer form of a protein that more closely resembles dystrophin.

The first of these “exon-skipping” drugs, Exondys 51, was granted accelerated approval in 2016—despite the fact that the clinical trial was not placebo controlled and included only 12 boys. “I’ve never seen anything like it,” says Zuckerman. She points out that the study was far too small to be able to prove the drug worked. In her view, 2016 was “a turning point” for FDA approvals based on low-quality evidence—“It was so extreme,” she says.

Since then, three other exon-skipping drugs have received accelerated approval for Duchenne—two of them from Sarepta. A Sarepta spokesperson said a company-funded analysis showed that people with Duchenne who received Exondys 51 remained ambulatory longer and lived longer by 5.4 years—“data we would not have without that initial approval.”

But for many in the scientific community, that data still needs to be confirmed. “The clinical benefit still has not been confirmed for any of the four,” Mike Singer, a clinical reviewer in the FDA’s Office of Therapeutic Products, told the advisory committee in May. 

“All of them are wanted by the families, but none of them have ever been proven to work,” says Zuckerman.  

Will Roberts is one of the boys taking an exon-­skipping drug—specifically, Sarepta’s Amondys 45. Now 10, he was diagnosed with Duchenne when he was just one year old. His treatment involves having a nurse come to his home and inject him every five to 10 days. And it’s not cheap. While his parents have a specialist insurance policy that shields them from the cost, the price of a year’s worth of treatment is around $750,000. 

portrait of the Roberts family in the autumn
Will Roberts (left), who is now 10 years old, has been taking Sarepta’s Amondys 45 to treat his Duchenne muscular dystrophy since he was a year old, but he has seen little improvement. His parents, Ryan and Keyan, were hoping that SRP-9001 would be approved by the FDA.
COURTESY OF THE ROBERTS FAMILY

Will’s mother, Keyan Roberts, a teacher in Michigan, says she can’t tell if the drug is helping him. Last year he was running around in their backyard, but this year he needs a power chair to get around at school. “We definitely didn’t see any gains in ability, and it’s hard to tell if it made his decline … a little less steep,” Roberts says.

The treatment comes with risks, too. The Amondys 45 website warns that 20% of people who get the drug experience adverse reactions, and that “potentially fatal” kidney damage has been seen in people treated with a similar drug. 

Roberts says she is aware of the risks that come with taking drugs like Amondys. But she and her husband, Ryan, an IT manager, were still hoping that SRP-9001 would be approved by the FDA. For the Robertses and parents like them, part of the desire is based on the hope, no matter how slim, that their child might benefit. 

“We really feel strongly that we’re in a position now where we’re seeing [Will’s] mobility decline, and we’re nervous that … he might not qualify to take it by the time it’s made available,” she said in a video call, a couple of weeks after the advisory committee meeting.

Selling hope

On June 22, just over a month after the committee meeting, the FDA approved SRP-9001, now called Elevidys. It will cost $3.2 million for the one-off treatment, before any potential discounts. For the time being, the approval is restricted to four- and five-year-olds. It was granted with a reminder to the company to complete the ongoing trials and report back on the results.

Sarepta maintains that there is sufficient evidence to support the drug’s approval. But this drug and others have been made available—at eye-wateringly high prices—without the strong evidence we’d normally expect for new medicines. Is it ever ethical to sell a drug when we don’t fully know whether it will work? 

I put this question to Debra Miller, mother of Hawken Miller and founder of CureDuchenne. Hawken was diagnosed when he was five years old. “The doctor that diagnosed him basically told us that he was going to stop walking around 10 years old, and he would not live past 18,” she says. “‘There’s no treatment. There’s no cure. There’s nothing you can do. Go home and love your child.’”

She set up CureDuchenne in response. The organization is dedicated to funding research into potential treatments and cures, and to supporting people affected by the disease. It provided early financial support to Sarepta but does not have a current financial interest in the company. Hawken, now a content strategist for CureDuchenne, has never been eligible for a clinical trial.

Debra Miller says she’s glad that the exon-skipping drugs were approved. From her point of view, it’s about more than making a new drug accessible.

“We all want hope. But in medicine, isn’t it better to have hope based on evidence rather than hope based on hype?”

Diana Zuckerman, president of the National Center for Health Research

“[The approvals] drove innovation and attracted a lot of attention to Duchenne,” she says. Since then, CureDuchenne has funded other companies exploring next-generation exon-skipping drugs that, in early experiments, seem to work better than the first-generation drugs. “You have to get to step one before you can get to step two,” she says.

Hawken Miller is waiting for the data from an ongoing phase 3 clinical trial of Elevidys. For the time being, “from a data perspective, it doesn’t look great,” he says. “But at the same time, I hear a lot of anecdotes from parents and patients who say it’s really helping a lot, and I don’t want to discount what they’re seeing.”

Results were due in September—just three months after the accelerated approval was granted. It might not seem like much of a wait, but every minute is precious to children with Duchenne. “Time is muscle” was the refrain repeated throughout the advisory committee meeting. 

“I wish that we had the time and the muscle to wait for things that were more effective,” says Keyan Roberts, Will’s mom. “But one of the problems with this disease is that we might not have the opportunity to wait to take one of those other drugs that might be made available years down the line.”

Doctors may end up agreeing that a drug—even one that is unlikely to work—is better than nothing. “In the American psyche, that is the approach that [doctors and] patients are pushed toward,” says Holly Fernandez Lynch, a bioethicist at the University of Pennsylvania. “We have all this language that you’re ‘fighting against the disease,’ and that you should try everything.”

“I can’t tell you how many FDA advisory committee meetings I’ve been to where the public-comment patients are saying something like ‘This is giving me hope,’” says Zuckerman. “Sometimes hope helps people do better. It certainly helps them feel better. And we all want hope. But in medicine, isn’t it better to have hope based on evidence rather than hope based on hype?”

A desperate decision

A drug approved on weak data might offer nothing more than false hope at a high price, Zuckerman says: “It is not fair for patients and their families to [potentially] have to go into bankruptcy for a drug that isn’t even proven to work.” 

The best way for people to access experimental treatments is still through clinical trials, says Bateman-House. Robertson, the health law expert, agrees, and adds that trials should be “bigger, faster, and more inclusive.” If a drug looks as if it’s working, perhaps companies could allow more volunteers to join the trial, for example. 

Their reasoning is that people affected by devastating diseases should be protected from ineffective and possibly harmful treatments—even if they want them. Review boards assess how ethical clinical trials are before signing off on them. Participants can’t be charged for drugs they take in clinical trials. And they are carefully monitored by medical professionals during their participation. 

That doesn’t mean people who are desperate for treatments are incapable of making good decisions. “They are stuck with bad choices,” says Fernandez Lynch. 

This is also the case for ultra-novel treatments, says Robertson. At the start of trials, the best candidates for all-new experimental therapies may be those who are closer to death, he says: “It is quite appropriate to select patients who have less to lose, while nonetheless being sure not to exploit people who don’t have any good options.” 

There’s another advantage to clinical trials. It’s hard to assess the effectiveness of a one-off treatment in any single individual. But clinical trials contribute valuable data that stands to benefit a patient community. Such data is especially valuable for treatments so new that there are few standards for comparison. 

Hawken Miller says he would consider taking part in an Elevidys clinical trial. “I’m willing to take on some of that risk for the potential of helping other people,” he says. “I think you’ll find that in [most of the Duchenne] community, everyone’s very willing to participate in clinical trials if it means helping kids get cured faster.”

When it comes to assessing the likelihood that Elevidys will work, Will’s dad, Ryan Roberts, says he’s a realist. “We’re really close to approaching the last chance—the last years he’ll be ambulatory,” he says. For him as a dad, he says, the efficacy concerns aren’t relevant. “We will take the treatment because it’s going to be the only chance we have … We are aware that we’re not being denied a treatment that is a cure, or a huge game-changer. But we are willing to take anything we can get in the short window we have closing now.” 

After 25 years of hype, embryonic stem cells are still waiting for their moment

Twenty-five years ago, in 1998, researchers in Wisconsin isolated powerful stem cells from human embryos. It was a fundamental breakthrough for biology, since these cells are the starting point for human bodies and have the capacity to turn into any other type of cell—heart cells, neurons, you name it.

National Geographic would later summarize the incredible promise: “the dream is to launch a medical revolution in which ailing organs and tissues might be repaired” with living replacements. It was the dawn of a new era. A holy grail. Pick your favorite cliché—they all got airtime.

Yet today, more than two decades later, there are no treatments on the market based on these cells. Not one.

To find out what happened, this June I grabbed a seat in the front row at the annual International Society for Stem Cell Research meeting, in an auditorium alongside hundreds of biologists. Projected on a huge screen was a slightly intimidating black-and-white image of cells seen through a microscope, some round with groping hair-like extensions, others rectangular cross-sections filled with a mysterious substance that looked like sand. Theme music bubbled from the stage: “I Want a New Drug,” by Huey Lewis and the News.

During the stem-cell meeting, I had a chance to meet old sources—some now literally so, scientists transmuted by a quarter-century and hard work into deans or wizened advisers. I asked: is 25 years and counting a normal time frame, or is something amiss with this vaunted technology? To most of the people I spoke with, the agonizing delay is no surprise. That’s how long it can take for a truly novel biotechnology to develop. The initial human test of a gene therapy occurred in 1980, but it wasn’t until 2012 that the first gene fix was approved for sale in Europe. By that yardstick, stem cells are on track.

Others concede that melding stem cells into medicine has proved surprisingly difficult. The basic challenge is that cells are not like aspirin or another drug that can be made by the pound. They’re living things, which can change, die, or even run out of control, causing dangers like cancer. By this account, capturing the embryonic stem cell was the easy part. It’s coaxing them to produce specialized cells—the kind with specific functions needed to treat disease—that’s been so hard.

“Ideas take a long time, but it’s still the right idea,” said Matthew Porteus, a professor from Stanford University whom I peppered with questions while he was standing at a podium at the meeting.

There are signs that stem-cell-based treatments are finally poised for a breakout. According to a 2023 survey, nearly 70 new tests on volunteers got underway in the last four years—triple the previous pace. The most advanced of these early human studies is being carried out by Vertex Pharmaceuticals, which in June said two diabetes patients who received injections of lab-made pancreatic cells no longer have to take insulin. Tests of manufactured cells to treat blindness and epilepsy also have early results that suggest transplanted cells are helping. 

“A lot of things are on the verge,” says Haifan Lin, a Harvard University professor who is the outgoing president of the ISSCR. “I don’t think it’s delayed, because stem cells are truly the most complicated of all cells.”

Tabula rasa

I have covered embryonic stem cells since the beginning— even a little bit before the beginning. Here at MIT Technology Review, we broke the story of the quest to isolate these cells, carried out under the looming threat of opposition from anti-abortion campaigners. Our July/August 1998 cover, “Biotech Taboo,” set the mood with a picture of a petri dish gleaming in the darkness.

“If awards were given for the most intriguing, controversial, and hush-hush of scientific pursuits,” I wrote, “the search for the embryonic stem cell would likely sweep the categories.” It was the search for a tabula rasa cell, we told readers—one able to give rise to any other type in the human body. The embryonic stem cell was a potential “factory in a dish” that could give scientists for the first time “the ability to grow human tissue at will.” And it was taboo because the cells existed only in early-stage human embryos, which could be obtained from IVF clinics but had to be destroyed in order to isolate the cells. 

July/August 1998 cover of MIT Technology Review
A moody 1998 cover of MIT Technology Review predicted the arrival of embryonic stem cells—and of an ethical controversy.
ROBERT CARDIN

A few months after our report, the scientific race reached its conclusion. That November, James Thomson at the University of Wisconsin reported he’d captured stem cells from five embryos and was keeping these cells alive, and multiplying, in his lab. 

Thomson’s paper, a succinct three-pager in the journal Science, contained a sketch of how he thought stem cells would become a medical technology. Where organs or cells from cadavers are in short supply, he predicted, stem cells “will provide a potentially limitless source of cells for drug discovery and transplantation medicine,” in particular by permitting “standardized production” of specialist cell types like beating heart cells or glucose-sensing beta cells. He noted that some diseases, specifically type 1 diabetes and Parkinson’s, result from “the death or dysfunction of just one or a few cell types.” If those specific cells could be replaced, it would mean “life-long treatment.”

That vision—that the mother of all cells could replace any tissue, or even regrow organs—is what electrified a generation of researchers. “That was the closest thing to magic that I have encountered. It’s a cell that keeps dividing and makes anything. If you are a cell biologist, that is the grail,” says Jeanne Loring, a professor emerita at the Scripps Research Institute and cofounder of Aspen Neuroscience, a company that plans to treat Parkinson’s disease with a transplant of dopamine-making cells. “The problem is, how do you make them into the precise cell type that you want?” What’s more, if stem cells are allowed to multiply in the lab, they can accumulate mutations, posing potential cancer risks: “That is the dark part of the magic.”

Political test

The stem-cell concept would shortly face a defining test—but it was political, not scientific. Because they’d been plucked from tiny, but living, IVF embryos, destroying them in the process, the discovery was met with outrage from the Catholic Church and other religious organizations in the US.  

Two years after Thomson’s paper, George W. Bush was elected president. Now Christian conservatives had a line into the White House, and they wanted federal funding for the research on the cells blocked. Scientists, aided by patient advocates, reacted with an overwhelming lobbying campaign. Yes to cures, they rallied. “I love stem cells,” read the bumper stickers.

That equation—stem cells equals cures—made the breakthroughs seem closer than they really were. Martin Pera, editor in chief of Stem Cell Reports, an academic journal, was part of the push: in an editorial that year, for example, he wrote that treatments would be realized “soon,” if only the government and charities would fund the science. “It was all in our imagination at the time,” Pera told me when I saw him at the ISSCR meeting. “Because all we had were undifferentiated stem cells.”

Timothy Caulfield, a health law professor at the University of Alberta, would later analyze news articles and determine that scientists consistently made “authoritative statements” with “unrealistic timelines” for when cures would come. “I don’t blame the researchers,” he says. “There is a microphone in front of them, and five or 10 years is close enough yet far enough away. You have to make it exciting, revolutionary. If not, the money is going somewhere else.”

But the public believed these time frames—as well as the story that only a lack of funding stood in the way of cures. So after the US introduced some limits on stem-cell research (allowing research funding on only a few supplies of the cells), patient groups struck back. In California, a 2004 ballot initiative, Proposition 71, established the California Institute of Regenerative Medicine. It made stem-cell research a “constitutional right” in the state and allotted $3 billion in tax funds for research over 10 years. By that time, lobbyists predicted, the initiative would pay for itself twice over through a bonanza of jobs and cures. Just treating type 1 diabetes (“in year six,” according to a projection) would save $122 billion in insulin and other costs. One TV ad said stem cells would cure “a million people with Parkinson’s.”

None of those cures has reached the market yet. And many of the patient advocates from those years, some of whom hoped stem cells would save them, are now dead: Jenifer Estess, David Ames, the actor Christopher Reeve, and Jordan Klein. The last was the son of Bob Klein, the California real estate entrepreneur who’d put Prop 71 into motion. After Jordan died from complications of type 1 diabetes in 2016, age 26, his father blamed political delays, according to the Long Beach Business Journal. “My youngest son died. If they hadn’t held it up in DC, he would be alive,” Klein told the publication.

“There was this dystopian-versus-utopian view of stem cells in the early 2000s.”

-Timothy Caulfield

The belief in stem-cell cures had become entrenched. To people like Klein, it was political meddling that was delaying them. “There was this dystopian-versus-utopian view of stem cells in the early 2000s,” says Caulfield. “You had people saying it’s unethical or immoral or shouldn’t be allowed. The research community, and I was part of it, had to push back and say this is an exciting area and we are going to save lives. And all this language has survived.” The clearest evidence? Fly-by-night medical clinics that started cashing in on the hype, advertising stem-cell cures for autism, migraines, and multiple sclerosis—a phenomenon Caulfied calls “scienceploitation.” For many years, any Google search for stem cells would return ads from shady clinics offering to treat just about anything, usually with cells collected from blood or fat tissue.

I learned how pervasive the phenomenon is this spring when an elderly acquaintance revealed she’d paid over $7,000 in cash for an injection of supposed stem cells drawn from her bones in the hopes of treating a painful knee. Of course, it likely didn’t do anything. She could have saved her money had she read a pamphlet from the ISSCR called “Guide to Stem Cell Treatments.” Despite its title, which sounds like a product glossary, it’s a lengthy warning about scam clinics, explaining that essentially any stem-cell treatment you see advertised today is a fake.

That’s because, in reality, nothing could make stem cells move faster than the speed of science. “When the promise of stem cells reached the public consciousness … there was the idea that stem cells are themselves a magic cure, even though that is ridiculous,” says Arnold Kriegstein, a professor at the University of California, San Francisco. “The true promise was not that the stem cells would do this, but that they were the starting point for the cells you wanted. And that is never simple. That is painstaking and slow. That is science—it’s laborious and takes time.”

Delayed promise

Stem-cell research is no longer as political as it once was. That’s partly because by 2006, scientists had determined how to convert any cell, like a bit of skin, into something like an embryonic stem cell. Such “induced” stem cells are largely identical to those from embryos, and without the ethical hangover. But whichever type of stem cell researchers choose, using them to manufacture mature, specialized cells (the kind you’d want for transplant) turned out to be more difficult than most expected. 

The strategy scientists have been taking to generate the cell types they want is called “directed differentiation.” You can think of directed differentiation as a cookbook approach—add this growth factor at day 2, that one on day 12, and so on—that exposes a stem cell to the same sorts of external cues it would receive if it were part of a developing baby.

While the cookbook process can be successful, it is extraordinarily difficult to hit on a correct recipe. For instance, the scientist Douglas Melton, who has two children with type 1 diabetes and who developed the Vertex treatment that’s now in testing, spent close to 15 years before he was able to produce “functional” pancreatic cells able to respond to glucose and make insulin when transplanted into a mouse. “That problem took much longer than I expected—I told my wife it would take five years,” Melton recounted to a Harvard publication in 2021.

Maturing into a wanted cell type takes stem cells about as long in a lab dish as it does during an actual pregnancy—even six or seven months.

What’s more, maturing into a wanted cell type can take stem cells as long in a lab as it does during an actual pregnancy—sometimes six or seven months. That’s been a significant obstacle to trying out new ideas, since each new test means a further long delay. “I was optimistic, but when you do the experiment, it can take 200 days,” says Hanae Lahlou, a principal scientist at Mass Eye and Ear, one of Harvard’s teaching hospitals. She was part of a project that tried using transplants to repair the hearing of guinea pigs. They hoped the engrafted cells would grow into new auditory hairs, but they never quite did. Now Lahlou is trying speedier genetic techniques rather than cell transplants. “At some point I didn’t see it as a therapeutic tool,” she says. “If you ask patients, they want a drug.”

Making cells isn’t cheap, either. Just a gram of their favorite growth factor costs $750,000. Add to that the regulatory barriers that face any untested approach, and it’s clear why biotechnology companies’ work with stem cells has been fitful. Geron, which once controlled a patent on embryonic stem cells and launched the first human test of a treatment created from them in 2010, canceled the study a year later. Now it works on cancer drugs and no longer mentions embryonic stem cells on its website. Another stem-cell company, Sana, has seen its stock value droop since its 2021 IPO and last year laid off a team trying to create heart muscle to treat cardiac disease. 

Early stage trials

High costs and technical difficulties aren’t unusual in the biotech world, and there is still a resilient cadre of investors and scientists who believe that stem-cell therapies are worth the risk. Today, stem-cell researchers say the increasing number of new clinical trials—about 15 are launching each year—is a sign the field may be close to a turning point. Transplants of lab-made retina cells (the approach tested most often so far) can’t be said to improve eyesight yet, but there is evidence from the initial handful of patients that the cells are doing something. According to a survey published last year, more than 3,000 patients have received transplants generated from induced or embryonic stem cells in around 90 studies, though all of these tests remain in their initial phases. 

“If you look around, all the trials are at an early stage. Not all are likely to produce cures, but they will give us information on how to improve and how to refine things,” says Pera.

For transplanted cells, one open question that can be answered only through experiments on people is how long those cells will survive. When dopamine-making neurons are added to the brains of Parkinson’s patients, something that’s been tried a few times, most of those neurons end up dying. Researchers have gone back to the drawing board, trying to figure out why, and how to adjust their tactics. Maybe they just need to crank up the dose, despite possible risks—too much dopamine is almost as bad as too little, and it can cause involuntary movements. The Vertex study on diabetes, which is expected to treat 40 people, looks more promising, but there too it remains unclear how long the added cells will live. It means a very costly treatment (some estimate a cell transplant for diabetes will run at least $500,000) might not be forever. 

Yet Loring is hopeful that one of these tests will soon lead to striking, incontrovertible proof that treatments crafted from embryonic stem cells can cure disease. “It could be the tipping point,” she says. “And I do think we need that moment.” 

Epilepsy treatment

During the three days I spent at the gathering of stem-cell researchers, one study stood out to me as looking like the big breakthrough this field needs. It’s a new trial being run by a biotech called Neurona Therapeutics, in San Francisco, which a year ago transplanted lab-made “inhibitory interneurons” deep into the brains of two people whose intractable epilepsy wasn’t responding to ordinary drugs. The bet is that these added cells will each form thousands of connections and quiet the malfunctioning brain networks that cause seizures.

During the meeting, Neurona announced that both patients have seen a 90%-plus reduction in seizures. In the case of one 26-year-old-man, that’s down from a debilitating 32 seizures a month. If the data holds up, it could mean the cell transplant is as effective as the most drastic treatment available for epilepsy today, which is surgical removal of part of the temporal lobe. But it wouldn’t have the side effects of getting part of your brain removed, like lost memories and vision. 

“There’s a lot of enthusiasm. This could be the first cell therapy for epilepsy,” says Kriegstein, the professor at the University of California, San Francisco, who is also an adviser to Neurona and its cofounder. Kriegstein told me he doesn’t think 25 years is a long time for this type of therapy to emerge. Instead, he counters, it’s “actually kind of fast.”

“There’s a lot of enthusiasm. This could be the first cell therapy for epilepsy.”

-Arnold Kriegstein

Doctors had experimented with neuron grafts before—one company tried using cells from pigs. But it was Cory Nicholas, a postdoctoral fellow in Kriegstein’s lab, who first determined, in 2013, how embryonic stem cells might be coaxed towards forming human interneurons in large quantities. What followed was what Kriegstein calls a series of “rational, systematic” steps over a decade to improve that recipe, run tests on animals, and win approval to start a human trial. Most of that work was done at Neurona, which has raised over $160 million and where Nicholas is CEO. 

 “Obviously, this wouldn’t be possible without embryonic [or induced] stem cells,” says Kriegstein. 

With only two patients treated, Neurona’s results remain anecdotal. But there’s a chance it’s an actual cure. That’s because the transplanted cells are likely still forming connections, and their effect may increase with time, possibly preventing seizures altogether. “It did seem like a pipe dream at first, but being able to make these cells in unlimited numbers is what let us try. Now we have patients who’ve been helped. It’s really quite amazing when you think about it,” says Kriegstein. “We are in the clinic. Cells are in patients, and we are going to see now how well they work. We are right at the point that the clinical trials will give us some clues. Was it just hype, or is it real?” 

Decoding the data of the Chinese mpox outbreak

This story first appeared in China Report, MIT Technology Review’s newsletter about technology developments in China. Sign up to receive it in your inbox every Tuesday.

Almost exactly a year after the World Health Organization declared mpox (formerly known as monkeypox) a public health emergency, the hot spot for the outbreak has quietly moved from the US and Europe to Asia. China in particular is experiencing a concerning increase in mpox cases right now.

This morning, I published a story on the developing mpox situation there and the government’s response so far. While Beijing did recently issue a guidance on mpox prevention, the country hasn’t taken a very proactive approach to containing the outbreak—a stark contrast from its strict covid policies (which I wrote about extensively last year).

It’s particularly worrying that the government hasn’t talked at all about using mpox vaccines, though there are three options available globally and they have proved to be effective at containing the mpox spread in countries including the United States

Beijing’s omission may be a result of “technology nationalism,” says Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations. But delaying the approval of effective foreign vaccines could stymie prevention and result in more dangerous outcomes, Huang warns—the same thing that happened with covid.

You can read more about the difficulties in containing the mpox spread in China in the story today. But in this newsletter, I want to highlight a different challenge: because of the way Beijing has so far reported mpox data and the way the WHO publishes it, it’s quite difficult to understand the exact scale of mpox in the country.

When I started reporting this story, I found that the only available mpox case count China has published is a one-time report tallying cases from June 2 to June 30. No information on weekly developments or cases from before or after June has been made public, even though other Asian countries, including Japan, started to see cases rise back in March. 

But when I looked up the WHO dashboard on the global mpox outbreak, with data starting in January 2022, I was surprised to find a consistent stream of new cases being reported by China several times a week, as recently as July 20.

For some time I thought this meant Chinese health authorities or researchers had been quietly reporting more timely data to the WHO while keeping the information inaccessible to the public. After all, something similar has happened before with covid data

Honestly, I found this data surprising and alarming. News about mpox in China has been mostly under the radar, but as the WHO overview explains: “In the most recent week of full reporting, 7 countries reported an increase in the weekly number of cases, with the highest increase reported in China.” The WHO data shows that from May to July, China reported 315 mpox cases, the most around the world in this time frame.

Sounds quite bad, right? 

It turns out the reality is a tad more complicated. On the WHO website, the recent mpox data listed under China is the sum of cases reported in China, Taiwan, and Hong Kong. 

The lack of data separation is significant here for a few reasons. First, while case counts have indeed risen in China, we don’t know by how much and over what time frame. China reported 106 cases in June alone, and it’s safe to assume there were additional cases in May and July. But there’s no information there to help us understand the exact urgency and severity of the outbreak, which can lead to panic and uninformed interventions. What’s more, as its handling of covid shows, the Chinese government may be holding onto data to serve its own interests. 

Beyond that, this combined data reporting obscures the fact that Taiwan and China, with their different governing bodies, have responded to public health emergencies in very different ways. 

While China has not signaled any interest in using mpox vaccines, Taiwan, which has its own CDC, has already administered over 72,000 shots so far. While China has only issued a one-month report of case counts, Taiwan has a public database showing how many new cases are reported each week, making it easy to see that the outbreak is on the decline there, six months after local transmission started. 

So aggregating very different sources of data creates a confusing landscape and makes it hard to follow the impact of public health measures.

This means that when the WHO data shows a 550% increase in weekly new cases in China between July 10 and July 17, the jump means little. It doesn’t reveal the direction of the mpox outbreak; it only emphasizes the broken, irregular pattern of case reporting from China. 

This is not to say the outbreak in China is insignificant, but that the data on the WHO website can easily mislead observers. 

It’s important to realize that despite how authoritative they may sound, international organizations like the WHO don’t have a magic source of data that overcomes the limited public health information coming out of China. It can only rely on individual countries to voluntarily report such data. (The WHO didn’t immediately respond to questions about its data aggregation practices; today is a public holiday in Switzerland, where it’s headquartered.)

Unfortunately, as the status of Taiwan remains one of the most sensitive security topics to Beijing, even the act of singling out the island’s public health data can be seen as a political move. That is larger than any technical obstacle. At a crucial time like this, transparent and timely case counting is one of the most important public health tools against infectious diseases. It’s too bad that politics is getting in the way of that. 

Do you think WHO should disaggregate the mpox data of China and Taiwan? What are your reasons? Tell me at zeyi@technologyreview.com.

Catch up with China

1. Chinese feminists are rushing out to support the Barbie movie. (But you can’t do a “Barbenheimer” double feature yet, since Oppenheimer isn’t arriving in China until August 30.) (Financial Times $)

2. The US government believes Chinese hackers have inserted malware into the communications, logistics, and supply networks of US military bases. (New York Times $)

3. A former party official in the city of Hangzhou, who oversaw the rise of tech giant Alibaba, was imprisoned for life for taking $25 million in bribes. (Bloomberg $)

4. Volkswagen bought a 5% stake in the Chinese electric vehicle company Xpeng, and the companies will jointly develop two EV models under the Volkswagen brand. (Wall Street Journal $)

5. TikTok’s newly launched ad library in Europe shows that Chinese major state media have run over 1,000 ads on the platform, even though TikTok’s policy forbids political ads. (Forbes)

6. Shein spent $600,000 on lobbying activities between April 1 and June 30, nearly three times its lobbying spending in the first quarter. (Business of Fashion)

7. China will restrict the export of long-range civilian drones, citing concerns that they might be converted to military use. (Associated Press)

8. A Taiwanese businessman accused of espionage and stealing state secrets was freed after two years in a Chinese jail. (BBC)

Lost in translation

A new AI photo generator app called 妙鸭相机 (Miaoya Camera), developed with support from a Alibaba-owned company, is all the rage in China right now. Users can upload 21 photos with their faces to create personalized portraits that look as if they were created by a professional. It’s priced at just 9.9 RMB ($1.38), a tiny fraction of what chain photography studios often charge. (These studios have become a popular business in recent years.)

Experts told Chinese publication Southern Metropolis Daily that the technology Miaoya Camera uses—mostly the open-source model Stable Diffusion and a technique called “low-rank adaptation of large language models” to improve the result—is nothing groundbreaking but just well packaged for the user experience. Expectedly, a controversy then arose about the broad data use permissions in the app’s user agreement; the app apologized and promised it will use personal data only to generate profile photos.

One more thing

These Barbies and Kens are from Dongbei, the northeastern region of China, where food portions are gigantic and people are often stereotyped as being straightforward and tough. (Sort of like the Texas of China, you know.) But really, these are created by an AI artist, Kim Wang, through Midjourney. I talked to Wang in a story earlier this year about using Midjourney to reimagine Chinese history.

China is suddenly dealing with another public health crisis: mpox

Hazmat suits, PCR tests, quarantines, and contact tracing—it was hard not to feel déjà vu last week when China’s Center for Disease Control and Prevention published new guidance on how to contain a disease outbreak. 

But what was happening was not another covid wave. Rather, the Chinese government was addressing a potentially significant new public health concern: mpox. The World Health Organization reports China is currently experiencing the world’s fastest increase in cases of mpox (formerly known as monkeypox), and the country needs to act fast to contain the spread.

While the Americas and Europe have mostly contained the mpox outbreak that started in mid-2022, Asia has emerged as the disease’s new hot spot. Japan, South Korea, and Thailand, which all saw sporadic imported cases last year, have reported weekly new case numbers in the double digits in 2023, meaning the virus has been spreading in the domestic population. But according to the latest data reported to the WHO, China has surpassed all other countries in the world, with 315 confirmed cases in just the past three months—though irregular case reporting from Beijing means it’s impossible to know the true scale of the disease at this point.  

Mpox is less contagious than covid, but since 2022, more than 88,000 people have contracted the disease, which can be painful and even debilitating for some. More than 150 people have died. Some countries have been more successful than others at containing domestic mpox outbreaks—and much of their success is arguably a result of proactive measures like vaccination campaigns.

But the Chinese government has barely started to take action. 

“Compared with the response to covid-19 … the [Chinese] response is certainly dramatically different,” says Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations. “Even though [mpox] is less likely to develop into a large outbreak in the country, the Pollyanna attitude may encourage the spread of the disease among the at-risk population—unless they take a more active campaign against the disease.”

How it’s spreading now

In May, the WHO declared that mpox was no longer a public health emergency of international concern (PHEIC) because cases had gone down significantly in countries that had seen large outbreaks last year, mostly in the Americas and Europe. (Mpox has been endemic in West and Central Africa for decades and remains so.) 

“Overall, compared to where we were last year, we’re definitely in a different place,” says Krutika Kuppalli, an infectious-disease physician and chair of the Infectious Disease Society of America’s Global Health Committee. “We have much fewer cases, but we are seeing sporadic outbreaks in different parts of the world.” 

Indeed, by the time the WHO rescinded the PHEIC declaration, many Asian countries were already starting to see an uptick. Japan was the first Asian country to report a significant increase in mpox cases, in March. In May, a report by researchers in the country warned that the disease could surge across Asia, owing to the connectedness between Japan and other Asian countries and the low mpox vaccination rate in the region. If the outbreak grows to the level that it did in the West, the researchers noted, over 10,000 cases might be expected in Japan alone before mpox is successfully contained.

It’s less clear what exactly is happening in China. According to data collected by the WHO, China reported 315 new mpox cases from May to July. A case count this high suggests that not all cases were travel related.

But—in another situation reminiscent of its covid response—China isn’t as forthcoming as other countries with its disease data; it doesn’t publish weekly reports of new cases. Rather, it has released a one-time report of the number of mpox cases recorded in June: 106. The Chinese government didn’t release data from May, and hasn’t released any data about July cases yet. 

The WHO, though, lumps together the case counts from Taiwan, which has its own government and CDC, and Hong Kong under the name of China. And there’s no way for the public to separate the data. So the 315 number includes the 106 cases Beijing says it identified in July, plus the number of infections in Taiwan and Hong Kong over May, June, and July. 

This all further obscures the true toll of mpox in China—even though it’s critical during an infectious-disease outbreak to be on top of things as soon as possible. 

The Chinese name for mpox—猴痘, or houdou—has also been thrown around casually as a slur against gay men.

“We also need to understand more about the people that have been infected,” Kuppalli says, “such as … the demographics, the clinical presentation, their immune status, and about how they’ve been presenting to care. I think that type of information is important.”

A muddled response that makes LGBTQ communities a target

The lack of clarity on how the disease has spread has caused some Chinese people to panic. The news that mpox cases have started to appear in the country has been circulating for weeks. But not until July 26 did China’s CDC and health ministry co-publish a new guidance on how to prevent its spread, and even that left unanswered questions. 

The directive asked that all confirmed mpox patients transfer to a medical facility for quarantine unless they have only mild symptoms. It said contact tracing going back three weeks would be conducted for every patient, and their close contacts would be asked to self-quarantine for three weeks. It also recommended that local authorities monitor the mpox virus level in wastewater around certain areas.

What makes monitoring the outbreak more difficult in China is that, as in the West, the current mpox spread has been seen mostly among communities of men who have sex with men (MSM). And similar to what happened in the US and Europe, that association is consistently misinterpreted in China to suggest that mpox is only an STD spread by gay men through sexual activities—a particularly dangerous connection, as the LGBTQ community is increasingly targeted in the country. 

Many Chinese social media users who have spotted men with skin lesions in public have been posting their photos to ask whether it’s an mpox symptom. And the Chinese name for mpox—猴痘, or houdou—has also been thrown around casually as a slur against gay men.

To efficiently stop the spread of mpox, public health officials need to strike a delicate balance between destigmatizing the disease by dispelling the idea that it affects only gay men and prioritizing the MSM communities that are most vulnerable to it. 

“Working with the people that are affected, helping to have non-stigmatizing language and communication, has been hugely effective in helping to curb the outbreak” in the West, Kuppalli says. 

So far, some local LGBTQ communities in China feel they’re on their own. 

M, who works for a queer rights organization in Guangzhou and asked to be identified only by his first initial given the sensitivity of his work, points out that the CDC recommended wastewater monitoring specifically near venues that MSM communities frequent, including bars, clubs, and saunas. He says this has become controversial within the Chinese LGBTQ community, and that some organizers feel this puts a target on their backs. 

“It will take a long time. I have some friends who have already traveled to Hong Kong or Macau to get vaccinated for mpox.” 

Another LGBTQ organizer, Suihou, who works in the central province of Hubei and asked to be identified by a pseudonym, tells MIT Technology Review that even though contact tracing information is supposed to be strictly confidential, he has seen one example in which an mpox patient’s private information, including phone number, national ID, address, and HIV status, was leaked and passed around on social media.

Organizers like M and Suihou are doing their own work to mobilize a disease response. To spread information about mpox prevention, M has recently sent text messages to 700 people and hosted in-person lectures that reached over 900 people.

And Suihou has worked with one mpox patient closely, helping him get testing and treatment. Not all the medical workers they’ve encountered have been trained on how to handle the sensitivity of these cases, he says; during the contact tracing process, the doctor told the patient that this disease is a problem for “your kind of people.”

Suihou warns that some people may avoid seeking medical help altogether, particularly given the lack of state support for mandatory quarantine and contact tracing. 

“From the individual cases that I have heard of, everyone who has a confirmed case is being asked to go to a quarantine facility,” Suihou says. But, he explains, since the government has not provided a budget to help cover the quarantine, as it did with covid, patients have no choice but to pay for the hospital stay and all medical tests out of their own pockets. Many marginalized individuals, who are also more vulnerable in an infectious-disease outbreak, may not be able to afford that.

“With the slowdown of the [Chinese] economy, local governments don’t have the physical capacity or even the willingness to invest more in public health,” Huang explains. Even the WHO doesn’t have funding specifically earmarked for mpox prevention; it has been using its emergency fund to cover mpox-related work. 

A lot of the financial burden will again fall on local organizers. M tells me that his organization is using funds intended for HIV prevention to conduct mpox outreach work.

All of this could further disincentivize people who get infected from seeking medical tests and treatment. This in turn would make the community spread of mpox even harder to track—and could undermine prevention efforts taken so far.

A lack of available vaccines

Much as with covid, vaccination is one of the best ways to get mpox under control. Worldwide, three vaccines are currently being used for mpox prevention: ACAM2000, MVA-BN (also known as JYNNEOS in the US), and Lc16m8. All these vaccines were originally designed for protection against smallpox but have been found effective against mpox. 

The US has administered more than 1.2 million JYNNEOS and ACAM2000 shots. And in Asia, South Korea imported 10,000 JYNNEOS shots last year and is planning to procure another 20,000 this year, while Taiwan, despite its small size, has procured and administered over 72,000 JYNNEOS shots so far. Japan, meanwhile, has relied on a Japanese company to produce its own Lc16m8, while also donating doses of the vaccine to countries including Colombia.

But none of these vaccines have been approved for use in China. The situation recalls how China refused to import any mRNA covid vaccines, instead relying on a few homegrown vaccines that were shown to be less effective. In this case, though, the country doesn’t currently produce any of its own smallpox vaccines; production was terminated after smallpox was eradicated globally in 1980. 

Bavarian Nordic, the Danish company that produces the JYNNEOS vaccine, tells MIT Technology Review that it can’t disclose client information unless requested by the government and can’t confirm whether China has procured any JYNNEOS shots. But it says the company is not in the process of applying to register the vaccine in China.

The WHO also has a sharing mechanism in place that allows member states to receive vaccines if needed. But it’s unclear whether China has applied for mpox vaccines. The organization did not immediately respond to an inquiry about whether there are plans to send vaccines to China.

The new Chinese CDC guidance on mpox made no mention of any vaccine as part of its outbreak response. “It’s quite unlikely that China will focus on procuring vaccines at this moment, since there’s no precedent and [no] emergency approval of the vaccines. Rather, there seems to be a focus on surveillance, monitoring, quarantine, contact tracing, etc.,” says Zoe Leung, a senior associate at Bridge Consulting, a Beijing-based communication consultancy specializing in public health.

It may not be this way forever: Sinopharm, a Chinese state-owned pharmaceutical company, announced last November that it had developed the world’s first mRNA vaccine against mpox, and it has been found effective in preclinical studies. On July 13, Sinopharm officially applied for clinical trial approval for a “replication-defective mpox vaccine,” though it’s unclear whether these are the same products. Sinopharm did not immediately reply to questions about its mpox vaccine development.

“There is domestic research [on a mpox vaccine], but we don’t know when it can be commercially available. It will take a long time,” says M, the organizer in Guangzhou. “I have some friends who have already traveled to Hong Kong or Macau to get vaccinated for mpox.” 

But for Chinese people to get vaccinations outside mainland China, there is often a high cost, a long wait time, and layers of bureaucracy to wade through. It’s again similar to trends seen earlier in the pandemic, when Chinese people with means traveled to Hong Kong to get mRNA covid vaccines.

“It doesn’t necessarily mean [Beijing is] not interested in vaccines,” says Huang, “but there’s this technology nationalism that discouraged them from rapid approval of the use of foreign vaccines.” And that, he warns, “certainly contributed to the rapid increase in covid-related mortalities.”  

This company plans to transplant gene-edited pig hearts into babies next year

The baby baboon is wearing a mesh gown and appears to be sitting upright. “This little lady … looks pretty philosophical, I would say,” says Eli Katz, who is showing me the image over a Zoom call.

This baboon is the first to receive a heart transplant from a young gene-edited pig as part of a study that should pave the way for similar transplants in human babies, says Katz, chief medical officer at the biotech company eGenesis.

The company, based in Cambridge, Massachusetts, has developed a technique that uses the gene-editing tool CRISPR to make around 70 edits to a pig’s genome. These edits should allow the organs to be successfully transplanted into people, the team says. As soon as next year, eGenesis hopes to transplant pig hearts into babies with serious heart defects. The goal is to buy them more time to wait for a human heart. 

Before that happens, the team at eGenesis will practice on 12 infant baboons. Two such surgeries have been performed so far. Neither animal survived beyond a matter of days.

But the company is optimistic, as are others in the field. Many recipients of the first liver transplants didn’t survive either—but thousands of people have since benefited from such transplants, says Robert Montgomery, director of the NYU Langone Transplant Institute, who has worked with rival company United Therapeutics. Babies born with heart conditions represent “a great population to be focusing on,” he says, “because so many of them die.”

Editing risk

Over 100,000 people in the US alone are waiting for an organ transplant. Every day, around 17 of them die. Researchers are exploring multiple options, including the possibility of bioprinting organs or growing new ones inside people’s bodies. Transplanting animal organs is another potential alternative to help meet the need.

The idea of using organs and tissues from animals, known as xenotransplantation, is an old one—the first experiments were performed back in the 17th century. More recent attempts were made in the 1960s, and again in the 1990s. Many of these used organs from monkeys and baboons. But toward the start of the 1990s, a consensus emerged that pigs were the best donor candidates, says Montgomery. 

Primates are precious—they are intelligent animals that experience complex emotions. Only a small number can be used for human research, and at any rate, they reproduce slowly. They are also more likely to be able to pass on harmful viruses. On the other hand, people already know a lot about how to rear and farm pigs, and their organs are about the right size for humans.

But transferring organs between animals of different species isn’t straightforward. Even organs from another human can be rejected by a recipient’s immune system, and animal tissues have a lot more components that our immune systems will regard as “foreign.” This can cause the organ to be attacked by immune cells. There’s also the possibility of transferring a virus along with the organ, for example. Even if a donor animal isn’t infected, it will have “endogenous retroviruses”—genetic code for ancient viruses that have long since been incorporated into its DNA.

These viruses don’t cause problems for their animal hosts. But there’s a chance they could cause an infection in another species. “There’s a risk that viruses that are endemic to animals evolve in a human and become deadly,” says Chris Gyngell, a bioethicist at Murdoch Children’s Research Institute in Melbourne, Australia.

The team at eGenesis is using CRISPR to address this risk. “You can use CRISPR-Cas9 to inactivate the 50 to 70 copies of retrovirus in the genome,” says Mike Curtis, president and chief executive officer at eGenesis. The edits prevent retroviruses from being able to replicate, he says.

Scientists at the company perform other gene edits, too. Several serve to “knock out” pig genes whose protein products trigger harmful immune responses in humans. And the team members insert seven human genes, which they believe should reduce the likelihood that the organ will be rejected by a human recipient’s immune system. In all, “we’re producing [organ] donors with over 70 edits,” says Curtis.

The team performs these edits on pig fibroblasts—cells that are found in connective tissue. Then they take the DNA-containing nuclei of edited cells and put them into pig egg cells. Once an egg is fertilized with sperm, the resulting embryo is implanted into the uterus of an adult pig. Eventually, cloned piglets are delivered by C-section. “It’s the same technology that was used to clone Dolly back in the ’90s,” says Curtis, referring to the famous sheep that was the first animal cloned from an adult cell.

eGenesis has around 400 cloned pigs housed at a research facility in the Midwest (he is reluctant to reveal the exact location because facilities have been targeted by animal rights protesters). And early last year, the company set up a “clean” facility to produce organs fit for humans. Anyone who enters has to shower and don protective gear to avoid bringing in any bugs that might infect the pigs. The 200 pigs currently at this center live in groups of 15 to 25, says Curtis: “It’s basically like a very clean barn. We control all the feed that comes in, and we have waste control and airflow control.” There’s no mud.

The pigs that don’t end up having their organs used will be closely studied, says Curtis. The company needs to understand how the numerous gene edits they implement affect an animal over the course of its life. The team also wants to know if the human genes continue to be expressed over time. Some of the pigs are over four years old, says Curtis. “So far, it looks good,” he adds. 

Five masked people in a lab doing tasks around a sedated donor pig laying on a metal bed
eGenesis researchers collect cells from a pig donor
EGENESIS

Complications

When it comes to organ transplants, size is important. Surgeons take care to match the size of a donor’s heart to that of the recipient. Baby baboons are small—only hearts taken from pigs aged one to two months old are suitable, says Curtis. Once they are transplanted, the hearts are expected to grow with the baboons.

The first baboon to get a pig heart, which was just under a year old, died within a day of surgery. “It was a surgical complication,” says Curtis. The intravenous tube providing essential fluids to the baboon became blocked, he says. “The animal had to be euthanized.”

A second baboon was operated on a few months later. The team encountered another surgical complication: this time, the surgeons couldn’t get the baboon’s blood vessels to stay attached to those in the pig’s organs. The baboon died nine days after the operation.

In both cases, “the heart itself was beating well,” says Curtis. “So far, the first two are very encouraging from cardiac performance … the hearts look good.” The surgeons who performed the operations are confident they’ll be able to avoid the surgical complications in the future, he says.

Tough decisions

Once the baboon trial is completed, the team at eGenesis wants to offer the pig hearts to babies under the age of two who were born with severe heart conditions. Such children have limited treatment options—human hearts of the right size are few and far between, and some of the devices used to treat heart conditions in adults aren’t suitable for little children with small hearts.

Curtis hopes the pig hearts could initially be used as a temporary measure for such children—essentially buying them more time to wait for a donated human heart. Once a potential recipient has been found, the company can seek approval for the surgery from the US Food and Drug Administration.

Ethicists will point out that babies won’t be able to give informed consent for surgery. That decision will come down to their caregiver, who will likely be in a dire situation, says Syd Johnson, a bioethicist at Upstate Medical University in Syracuse, New York. “These are parents who are desperate for anything that might save their child’s life,” she says.

But Gyngell thinks the focus should be on who has the most to gain from an experimental procedure like this. “The fact is that pediatric patients have a greater clinical need, because there are far fewer other options available to them,” he says.

Montgomery, who is himself the recipient of a donated human heart, agrees. He says he supports eGenesis’s goals. “These babies that have congenital heart disease … have a 50% mortality rate,” he says. “It’s a flip of a coin whether that kid is going to live or not.”

That reasoning doesn’t wash with Johnson. The procedure is risky, and a child whose immune system rejects the organ could suffer, she says: “One hundred percent of the patients who’ve been transplanted with an animal organ have died [soon after the procedure]—that’s just an inescapable fact.” David Bennett Sr., who was the first living person to receive a gene-edited pig heart, in 2022, died two months later

There are more risks when using organs from gene-edited animals, says Johnson. We still don’t know if these genetic modifications might affect human recipients, especially in the long term. “The desire to do something to save these babies [with heart conditions] is obviously very strong for everyone who is involved,” she says. “But we still need to be honest and transparent about what the risks are—and they are, to some extent, unknown.”

Montgomery himself has transplanted gene-edited pig organs into adults who have been declared brain dead. Those organs—which include kidneys and, in unpublished work, hearts—were from pigs bred by the rival company Revivicor, which was acquired by United Therapeutics. The experiments ran for just two or three days, but Montgomery plans to run a similar experiment in individuals who will be studied for a month after the transplant. So far, he says, “we’ve got very good results.”

He believes young children may be better candidates for pig organs than adults, because their immune systems are still developing and therefore might be less likely to reject the organ. “They may well have some level of tolerance,” he says.

A third baboon is due to receive a pig heart in August. The company plans to perform at least one such operation a month until 12 animals have been operated on. The team members hope they’ll be able to fix the surgical issues and enable the baboons to live longer. Some other non-human primates that have received kidneys from the gene-edited pigs have already survived over a year, says Curtis.

“When you’re pioneering something new, there’s a steep learning curve,” Montgomery says.