Why Are Autism Rates Steadily Rising?
Stefania Sterling was just 21 when she had her son, Charlie. She was young and healthy, with no genetic issues apparent in either her or her husband's family, so she expected Charlie to be typical.
"It is surprising that the prevalence of a significant disorder like autism has risen so consistently over a relatively brief period."
It wasn't until she went to a Mommy and Me music class when he was one, and she saw all the other one-year-olds walking, that she realized how different her son was. He could barely crawl, didn't speak, and made no eye contact. By the time he was three, he was diagnosed as being on the lower functioning end of the autism spectrum.
She isn't sure why it happened – and researchers, too, are still trying to understand the basis of the complex condition. Studies suggest that genes can act together with influences from the environment to affect development in ways that lead to Autism Spectrum Disorder (ASD). But rates of ASD are rising dramatically, making the need to figure out why it's happening all the more urgent.
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Indeed, the CDC's latest autism report, released last week, which uses 2016 data, found that the prevalence of ASD in four-year-old children was one in 64 children, or 15.6 affected children per 1,000. That's more than the 14.1 rate they found in 2014, for the 11 states included in the study. New Jersey, as in years past, was the highest, with 25.3 per 1,000, compared to Missouri, which had just 8.8 per 1,000.
The rate for eight-year-olds had risen as well. Researchers found the ASD prevalence nationwide was 18.5 per 1,000, or one in 54, about 10 percent higher than the 16.8 rate found in 2014. New Jersey, again, was the highest, at one in 32 kids, compared to Colorado, which had the lowest rate, at one in 76 kids. For New Jersey, that's a 175 percent rise from the baseline number taken in 2000, when the state had just one in 101 kids.
"It is surprising that the prevalence of a significant disorder like autism has risen so consistently over a relatively brief period," said Walter Zahorodny, an associate professor of pediatrics at Rutgers New Jersey Medical School, who was involved in collecting the data.
The study echoed the findings of a surprising 2011 study in South Korea that found 1 in every 38 students had ASD. That was the the first comprehensive study of autism prevalence using a total population sample: A team of investigators from the U.S., South Korea, and Canada looked at 55,000 children ages 7 to 12 living in a community in South Korea and found that 2.64 percent of them had some level of autism.
Searching for Answers
Scientists can't put their finger on why rates are rising. Some say it's better diagnosis. That is, it's not that more people have autism. It's that we're better at detecting it. Others attribute it to changes in the diagnostic criteria. Specifically, the May 2013 update of the Diagnostic and Statistical Manual of Mental Disorders-5 -- the standard classification of mental disorders -- removed the communication deficit from the autism definition, which made more children fall under that category. Cynical observers believe physicians and therapists are handing out the diagnosis more freely to allow access to services available only to children with autism, but that are also effective for other children.
Alycia Halladay, chief science officer for the Autism Science Foundation in New York, said she wishes there were just one answer, but there's not. While she believes the rising ASD numbers are due in part to factors like better diagnosis and a change in the definition, she does not believe that accounts for the entire rise in prevalence. As for the high numbers in New Jersey, she said the state has always had a higher prevalence of autism compared to other states. It is also one of the few states that does a good job at recording cases of autism in its educational records, meaning that children in New Jersey are more likely to be counted compared to kids in other states.
"Not every state is as good as New Jersey," she said. "That accounts for some of the difference compared to elsewhere, but we don't know if it's all of the difference in prevalence, or most of it, or what."
"What we do know is that vaccinations do not cause autism."
There is simply no defined proven reason for these increases, said Scott Badesch, outgoing president and CEO of the Autism Society of America.
"There are suggestions that it is based on better diagnosis, but there are also suggestions that the incidence of autism is in fact increasing due to reasons that have yet been determined," he said, adding, "What we do know is that vaccinations do not cause autism."
Zahorodny, the pediatrics professor, believes something is going on beyond better detection or evolving definitions.
"Changes in awareness and shifts in how children are identified or diagnosed are relevant, but they only take you so far in accounting for an increase of this magnitude," he said. "We don't know what is driving the surge in autism recorded by the ADDM Network and others."
He suggested that the increase in prevalence could be due to non-genetic environmental triggers or risk factors we do not yet know about, citing possibilities including parental age, prematurity, low birth rate, multiplicity, breech presentation, or C-section delivery. It may not be one, but rather several factors combined, he said.
"Increases in ASD prevalence have affected the whole population, so the triggers or risks must be very widely dispersed across all strata," he added.
There are studies that find new risk factors for ASD almost on a daily basis, said Idan Menashe, assistant professor in the Department of Health at Ben-Gurion University of the Negev, the fastest growing research university in Israel.
"There are plenty of studies that find new genetic variants (and new genes)," he said. In addition, various prenatal and perinatal risk factors are associated with a risk of ASD. He cited a study his university conducted last year on the relationship between C-section births and ASD, which found that exposure to general anesthesia may explain the association.
Whatever the cause, health practitioners are seeing the consequences in real time.
"People say rates are higher because of the changes in the diagnostic criteria," said Dr. Roseann Capanna-Hodge, a psychologist in Ridgefield, CT. "And they say it's easier for children to get identified. I say that's not the truth and that I've been doing this for 30 years, and that even 10 years ago, I did not see the level of autism that I do see today."
Sure, we're better at detecting autism, she added, but the detection improvements have largely occurred at the low- to mid- level part of the spectrum. The higher rates of autism are occurring at the more severe end, in her experience.
A Polarizing Theory
Among the more controversial risk factors scientists are exploring is the role environmental toxins may play in the development of autism. Some scientists, doctors and mental health experts suspect that toxins like heavy metals, pesticides, chemicals, or pollution may interrupt the way genes are expressed or the way endocrine systems function, manifesting in symptoms of autism. But others firmly resist such claims, at least until more evidence comes forth. To date, studies have been mixed and many have been more associative than causative.
"Today, scientists are still trying to figure out whether there are other environmental changes that can explain this rise, but studies of this question didn't provide any conclusive answer," said Menashe, who also serves as the scientific director of the National Autism Research Center at BGU.
"It's not everything that makes Charlie. He's just like any other kid."
That inconclusiveness has not dissuaded some doctors from taking the perspective that toxins do play a role. "Autism rates are rising because there is a mismatch between our genes and our environment," said Julia Getzelman, a pediatrician in San Francisco. "The majority of our evolution didn't include the kinds of toxic hits we are experiencing. The planet has changed drastically in just the last 75 years –- it has become more and more polluted with tens of thousands of unregulated chemicals being used by industry that are having effects on our most vulnerable."
She cites BPA, an industrial chemical that has been used since the 1960s to make certain plastics and resins. A large body of research, she says, has shown its impact on human health and the endocrine system. BPA binds to our own hormone receptors, so it may negatively impact the thyroid and brain. A study in 2015 was the first to identify a link between BPA and some children with autism, but the relationship was associative, not causative. Meanwhile, the Food and Drug Administration maintains that BPA is safe at the current levels occurring in food, based on its ongoing review of the available scientific evidence.
Michael Mooney, President of St. Louis-based Delta Genesis, a non-profit organization that treats children struggling with neurodevelopmental delays like autism, suspects a strong role for epigenetics, which refers to changes in how genes are expressed as a result of environmental influences, lifestyle behaviors, age, or disease states.
He believes some children are genetically predisposed to the disorder, and some unknown influence or combination of influences pushes them over the edge, triggering epigenetic changes that result in symptoms of autism.
For Stefania Sterling, it doesn't really matter how or why she had an autistic child. That's only one part of Charlie.
"It's not everything that makes Charlie," she said. "He's just like any other kid. He comes with happy moments. He comes with sad moments. Just like my other three kids."
This month, Leaps.org had a chance to speak with Holden Thorp, Editor-in-Chief of the Science family of journals. We talked about the best ways to communicate science to the public, mistakes by public health officials during the pandemic, the lab leak theory, and bipartisanship for funding science research.
Before becoming editor of the Science journals, Thorp spent six years as provost of Washington University in St. Louis, where he is Rita Levi-Montalcini Distinguished University Professor and holds appointments in both chemistry and medicine. He joined Washington University after spending three decades at the University of North Carolina at Chapel Hill, where he served as the UNC's 10th chancellor from 2008 through 2013.
A North Carolina native, Thorp earned a doctorate in chemistry in 1989 at the California Institute of Technology and completed postdoctoral work at Yale University. He is a fellow of the National Academy of Inventors and the American Association for the Advancement of Science.
Read his full bio here.
This conversation was lightly edited by Leaps.org for style and format.
Matt Fuchs: You're a musician. It seems like many scientists are also musicians. Is there a link between the scientist brain and the musician brain?
Holden Thorp: I think [the overlap is] relatively common. I'm still a gigging bass player. I play in the pits for lots of college musicals. I think that it takes a certain discipline and requires you to learn a lot of rules about how music works, and then you try to be creative within that. That's similar to scientific research. So it makes sense. Music is something I've been able to sustain my whole life. I wouldn't be the same person if I let it go. When you're playing, especially for a musical, where the music is challenging, you can't let your mind wander. It’s like meditation.
MF: I bet it helps to do something totally different from your editing responsibilities. Maybe lets the subconscious take care of tough problems at work.
HT: Right.
MF: There's probably never been a greater need for clear and persuasive science communicators. Do we need more cross specialty training? For example, journalism schools prioritizing science training, and science programs that require more time learning how to communicate effectively?
HT: I think we need both. One of the challenges we've had with COVID has been, especially at the beginning, a lot of reporters who didn’t normally cover scientific topics got put on COVID—and ended up creating things that had to be cleaned up later. This isn't the last science-oriented crisis we're going to have. We've already got climate change, and we'll have another health crisis for sure. So it’d be good for journalism to be a little better prepared next time.
"Scientists are human beings who have ego and bravado and every other human weakness."
But on the other side, maybe it's even more important that scientists learn how to communicate and how likely it is that their findings will be politicized, twisted and miscommunicated. Because one thing that surprised me is how shocked a lot of scientists have been. Every scientific issue that reaches into public policy becomes politicized: climate change, evolution, stem cells.
Once one side decided to be cautious about the pandemic, you could be certain the other side was going to decide not to do that. That's not the fault of science. That’s just life in a political world. That, I think, caught people off guard. They weren't prepared to shape and process their messages in a way that accounted for that—and for the way that social media has intensified all of this.
MF: Early in the pandemic, there was a lack of clarity about public health recommendations, as you’d expect with a virus we hadn’t seen before. Should public officials and scientists have more humility in similar situations in the future? Public officials need to be authoritative for their guidance to be followed, so how do they lead a crisis response while displaying humility about what we don't know?
HS: I think scientists are people who like to have the answer. It's very tempting and common for scientists to kind of oversell what we know right now, while not doing as much as we should to remind people that science is a self-correcting process. And when we fail to do that – after we’ve collected more data and need to change how we're interpreting it – the people who want to undermine us have a perfect weapon to use against us. It's challenging. But I agree that scientists are human beings who have ego and bravado and every other human weakness.
For example, we wanted to tell everybody that we thought the vaccines would provide sterilizing immunity against infection. Well, we don't have too many other respiratory viruses where that's the case. And so it was more likely that we were going to have what we ended up with, which is that the vaccines were excellent in preventing severe disease and death. It would have been great if they provided sterilizing immunity and abruptly ended the pandemic a year ago. But it was overly optimistic to think that was going to be the case in retrospect.
MF: Both in terms of how science is communicated and received by the public, do we need to reform institutions or start new ones to instill the truth-seeking values that are so important to appreciating science?
HS: There are a whole bunch of different factors. I think the biggest one is that the social media algorithms reward their owners financially when they figure out how to keep people in their silos. Users are more likely to click on things that they agree with—and that promote conflict with people that they disagree with. That has caused an acceleration in hostilities that attend some of these disagreements.
But I think the other problem is that we haven’t found a way to explain things to people when it’s not a crisis. So, for example, a strong indicator of whether someone who might otherwise be vaccine hesitant decided to get their vaccine is if they understood how vaccines worked before the pandemic started. Because if you're trying to tell somebody that they're wrong if they don't get a vaccine, at the same time you're trying to explain how it works, that's a lot of explaining to do in a short period of time.
Lack of open-mindedness is a problem, but another issue is that we need more understanding of these issues baked into the culture already. That's partly due the fact that there hasn't been more reform in K through 12 and college teaching. And that scientists are very comfortable talking to each other, and not very comfortable talking to people who don't know all of our jargon and have to be persuaded to spend time listening to and thinking about what we're trying to tell them.
"We're almost to the point where clinging to the lab leak idea is close to being a fringe idea that almost doesn't need to be included in stories."
MF: You mentioned silos. There have been some interesting attempts in recent years to do “both sides journalism,” where websites like AllSides put different views on high profile issues side-by-side. Some people believe that's how the news should be reported. Should we let people see and decide for themselves which side is the most convincing?
HS: It depends if we're talking about science. On scientific issues, when they start, there's legitimate disagreement about among scientists. But eventually, things go back and forth, and people compete with each other and work their way to the answer. At some point, we reach more of a consensus.
For example, on climate change, I think it's gotten to the point now where it's irresponsible, if you're writing a story about climate change, to run a quote from somebody somewhere who's still—probably because of their political views—clinging to the idea that anthropogenic global warming is somehow not damaging the planet.
On things that aren't decided yet, that makes sense to run both. It's more a question of judgment of the journalists. I don't think the solution to it is put stark versions of each side, side-by-side and let people choose. The whole point of journalism is to inform people. If there's a consensus on something, that's part of what you're supposed to be informing them about.
MF: What about reporting on perspectives about the lab leak theory at various times during the pandemic?
HS: We’re the outlet that ran the letter that really restarted the whole debate. A bunch of well-known scientists said we should consider the lab leak theory more carefully. And in the aftermath of that, a bunch of those scientists who signed that letter concluded that the lab leak was very, very unlikely. Interestingly, publishing that letter actually drove us to more of a consensus. I would say now, we're almost to the point where clinging to the lab leak idea is close to being a fringe idea that almost doesn't need to be included in stories. But I would say there's been a lot of evolution on that over the last year since we ran that letter.
MF: Let's talk about bipartisanship in Congress. Research funding for the National Institutes of Health was championed for years by influential Republicans who supported science to advance health breakthroughs. Is that changing? Maybe especially with Sen. Roy Blunt retiring? Has bipartisanship on science funding been eroded by political battles during COVID?
HS: I'm optimistic that that won't be the case. Republican Congresses have usually been good for science funding. And that's because (former Sen.) Arlen Specter and Roy Blunt are two of the political figures who have pushed for science funding over the last couple decades. With Blunt retiring, we don't know who's going to step in for him. That's an interesting question. I hope there will be Republican champions for science funding.
MF: Is there too much conservatism baked into how we research new therapies and bring them to people who are sick, bench-to-bedside? I'm thinking of the criticisms that NIH or the FDA are overly bureaucratic. Are you hopeful about ARPA-H, President Biden’s proposed new agency for health innovation?
HS: I think the challenge hasn't been cracked by the federal government. Maybe DARPA has done this outside of health science, but within health science, the federal government has had limited success at funding things that can be applied quickly, while having overwhelming success at funding basic research that eventually becomes important in applications. Can they do it the other way around? They’ll need people running ARPA-H who are application first. It’s ambitious. The way it was done in Operation Warp Speed is all the money was just given to the companies. If the hypothesis on ARPA-H is for the federal government to actually do what Moderna and BioNTech did for the vaccine, themselves, that's a radical idea. It's going to require thinking very differently than the way they think about dispersing grants for basic research.
MF: You’ve written a number of bold op-eds as editor of the Science journals. Are there any op-eds you're especially proud of as voicing a view that was important but not necessarily popular?
HS: I was one of the first people to come out hard against President Trump['s handling of] the pandemic. Lots of my brothers and sisters came along afterwards. To the extent that I was able to catalyze that, I'm proud of doing it. In the last few weeks, I published a paper objecting to the splitting of the OSTP director from the science advisor and, especially, not awarding the top part of the job to Alondra Nelson, who is a distinguished scientist at black female. And instead, giving part of it to Francis Collins. He’s certainly the most important science policy figure of my lifetime, but somebody who’s been doing this now for decades. I just think we have to push as hard as we can to get a cadre of young people leading us in Washington who represent the future of the country. I think the Biden administration leaned on a lot of figures from the past. I’m pushing them hard to try to stop it.
MF: I want to circle back to the erosion of the public’s trust in experts. Most experts are specialists, and specialists operate in silos that don’t capture the complexity of scientific knowledge. Are some pushbacks to experts and concerns about the perils of specialization valid?
HS: You're on the right track there. What we need is more respect for the generalist. We can't help the fact that you have to be very specialized to do a lot of stuff. But what we need is more partnership between specialists and people who can cross fields, especially into communication and social sciences. That handoff is just not really there right now. It's hard to get a hardcore scientist to respect people who are interested in science, education and science communication, and to treat them as equals. The last two years showed that they're at least as important, if not more so.
MF: I’m grateful that you’re leading the way in this area, Holden. Thank you for sharing your thoughts and your work.
Doug Olson was 49 when he was diagnosed with chronic lymphocytic leukemia, a blood cancer that strikes 21,000 Americans annually. Although the disease kills most patients within a decade, Olson’s case progressed more slowly, and courses of mild chemotherapy kept him healthy for 13 years. Then, when he was 62, the medication stopped working. The cancer had mutated, his doctor explained, becoming resistant to standard remedies. Harsher forms of chemo might buy him a few months, but their side effects would be debilitating. It was time to consider the treatment of last resort: a bone-marrow transplant.
Olson, a scientist who developed blood-testing instruments, knew the odds. There was only a 50 percent chance that a transplant would cure him. There was a 20 percent chance that the agonizing procedure—which involves destroying the patient’s marrow with chemo and radiation, then infusing his blood with donated stem cells—would kill him. If he survived, he would face the danger of graft-versus-host disease, in which the donor’s cells attack the recipient’s tissues. To prevent it, he would have to take immunosuppressant drugs, increasing the risk of infections. He could end up with pneumonia if one of his three grandchildren caught a sniffle. “I was being pushed into a corner,” Olson recalls, “with very little room to move.”
Soon afterward, however, his doctor revealed a possible escape route. He and some colleagues at the University of Pennsylvania’s Abramson Cancer Center were starting a clinical trial, he said, and Olson—still mostly symptom-free—might be a good candidate. The experimental treatment, known as CAR-T therapy, would use genetic engineering to turn his T lymphocytes (immune cells that guard against viruses and other pathogens) into a weapon against cancer.
In September 2010, technicians took some of Olson’s T cells to a laboratory, where they were programmed with new molecular marching orders and coaxed to multiply into an army of millions. When they were ready, a nurse inserted a catheter into his neck. At the turn of a valve, his soldiers returned home, ready to do battle.
“I felt like I’d won the lottery,” Olson says. But he was only the second person in the world to receive this “living drug,” as the University of Pennsylvania investigators called it. No one knew how long his remission would last.
Three weeks later, Olson was slammed with a 102-degree fever, nausea, and chills. The treatment had triggered two dangerous complications: cytokine release syndrome, in which immune chemicals inflame the patient’s tissues, and tumor lysis syndrome, in which toxins from dying cancer cells overwhelm the kidneys. But the crisis passed quickly, and the CAR-T cells fought on. A month after the infusion, the doctor delivered astounding news: “We can’t find any cancer in your body.”
“I felt like I’d won the lottery,” Olson says. But he was only the second person in the world to receive this “living drug,” as the University of Pennsylvania investigators called it. No one knew how long his remission would last.
An Unexpected Cure
In February 2022, the same cancer researchers reported a remarkable milestone: the trial’s first two patients had survived for more than a decade. Although Olson’s predecessor—a retired corrections officer named Bill Ludwig—died of COVID-19 complications in early 2021, both men had remained cancer-free. And the modified immune cells continued to patrol their territory, ready to kill suspected tumor cells the moment they arose.
“We can now conclude that CAR-T cells can actually cure patients with leukemia,” University of Pennsylvania immunologist Carl June, who spearheaded the development of the technique, told reporters. “We thought the cells would be gone in a month or two. The fact that they’ve survived 10 years is a major surprise.”
Even before the announcement, it was clear that CAR-T therapy could win a lasting reprieve for many patients with cancers that were once a death sentence. Since the Food and Drug Administration approved June’s version (marketed as Kymriah) in 2017, the agency has greenlighted five more such treatments for various types of leukemia, lymphoma, and myeloma. “Every single day, I take care of patients who would previously have been told they had no options,” says Rayne Rouce, a pediatric hematologist/oncologist at Texas Children’s Cancer Center. “Now we not only have a treatment option for those patients, but one that could potentially be the last therapy for their cancer that they’ll ever have to receive.”
Immunologist Carl June, middle, spearheaded development of the CAR-T therapy that gave patients Bill Ludwig, left, and Doug Olson, right, a lengthy reprieve on their terminal cancer diagnoses.
Penn Medicine
Yet the CAR-T approach doesn’t help everyone. So far, it has only shown success for blood cancers—and for those, the overall remission rate is 30 to 40 percent. “When it works, it works extraordinarily well,” says Olson’s former doctor, David Porter, director of Penn’s blood and bone marrow transplant program. “It’s important to know why it works, but it’s equally important to know why it doesn’t—and how we can fix that.”
The team’s study, published in the journal Nature, offers a wealth of data on what worked for these two patients. It may also hold clues for how to make the therapy effective for more people.
Building a Better T Cell
Carl June didn’t set out to cure cancer, but his serendipitous career path—and a personal tragedy—helped him achieve insights that had eluded other researchers. In 1971, hoping to avoid combat in Vietnam, he applied to the U.S. Naval Academy in Annapolis, Maryland. June showed a knack for biology, so the Navy sent him on to Baylor College of Medicine. He fell in love with immunology during a fellowship researching malaria vaccines in Switzerland. Later, the Navy deployed him to the Fred Hutchinson Cancer Research Center in Seattle to study bone marrow transplantation.
There, June became part of the first research team to learn how to culture T cells efficiently in a lab. After moving on to the National Naval Medical Center in the ’80s, he used that knowledge to combat the newly emerging AIDS epidemic. HIV, the virus that causes the disease, invades T cells and eventually destroys them. June and his post-doc Bruce Levine developed a method to restore patients’ depleted cell populations, using tiny magnetic beads to deliver growth-stimulating proteins. Infused into the body, the new T cells effectively boosted immune function.
In 1999, after leaving the Navy, June joined the University of Pennsylvania. His wife, who’d been diagnosed with ovarian cancer, died two years later, leaving three young children. “I had not known what it was like to be on the other side of the bed,” he recalls. Watching her suffer through grueling but futile chemotherapy, followed by an unsuccessful bone-marrow transplant, he resolved to focus on finding better cancer treatments. He started with leukemia—a family of diseases in which mutant white blood cells proliferate in the marrow.
Cancer is highly skilled at slipping through the immune system’s defenses. T cells, for example, detect pathogens by latching onto them with receptors designed to recognize foreign proteins. Leukemia cells evade detection, in part, by masquerading as normal white blood cells—that is, as part of the immune system itself.
June planned to use a viral vector no one had tried before: HIV.
To June, chimeric antigen receptor (CAR) T cells looked like a promising tool for unmasking and destroying the impostors. Developed in the early ’90s, these cells could be programmed to identify a target protein, and to kill any pathogen that displayed it. To do the programming, you spliced together snippets of DNA and inserted them into a disabled virus. Next, you removed some of the patient’s T cells and infected them with the virus, which genetically hijacked its new hosts—instructing them to find and slay the patient’s particular type of cancer cells. When the T cells multiplied, their descendants carried the new genetic code. You then infused those modified cells into the patient, where they went to war against their designated enemy.
Or that’s what happened in theory. Many scientists had tried to develop therapies using CAR-T cells, but none had succeeded. Although the technique worked in lab animals, the cells either died out or lost their potency in humans.
But June had the advantage of his years nurturing T cells for AIDS patients, as well as the technology he’d developed with Levine (who’d followed him to Penn with other team members). He also planned to use a viral vector no one had tried before: HIV, which had evolved to thrive in human T cells and could be altered to avoid causing disease. By the summer of 2010, he was ready to test CAR-T therapy against chronic lymphocytic leukemia (CLL), the most common form of the disease in adults.
Three patients signed up for the trial, including Doug Olson and Bill Ludwig. A portion of each man’s T cells were reprogrammed to detect a protein found only on B lymphocytes, the type of white blood cells affected by CLL. Their genetic instructions ordered them to destroy any cell carrying the protein, known as CD19, and to multiply whenever they encountered one. This meant the patients would forfeit all their B cells, not just cancerous ones—but regular injections of gamma globulins (a cocktail of antibodies) would make up for the loss.
After being infused with the CAR-T cells, all three men suffered high fevers and potentially life-threatening inflammation, but all pulled through without lasting damage. The third patient experienced a partial remission and survived for eight months. Olson and Ludwig were cured.
Learning What Works
Since those first infusions, researchers have developed reliable ways to prevent or treat the side effects of CAR-T therapy, greatly reducing its risks. They’ve also been experimenting with combination therapies—pairing CAR-T with chemo, cancer vaccines, and immunotherapy drugs called checkpoint inhibitors—to improve its success rate. But CAR-T cells are still ineffective for at least 60 percent of blood cancer patients. And they remain in the experimental stage for solid tumors (including pancreatic cancer, mesothelioma, and glioblastoma), whose greater complexity make them harder to attack.
The new Nature study offers clues that could fuel further advances. The Penn team “profiled these cells at a level where we can almost say, ‘These are the characteristics that a T cell would need to survive 10 years,’” says Rouce, the physician at Texas Children’s Cancer Center.
One surprising finding involves how CAR-T cells change in the body over time. At first, those that Olson and Ludwig received showed the hallmarks of “killer” T-cells (also known as CD8 cells)—highly active lymphocytes bent on exterminating every tumor cell in sight. After several months, however, the population shifted toward “helper” T-cells (or CD4s), which aid in forming long-term immune memory but are normally incapable of direct aggression. Over the years, the numbers swung back and forth, until only helper cells remained. Those cells showed markers suggesting they were too exhausted to function—but in the lab, they were able not only to recognize but to destroy cancer cells.
June and his team suspect that those tired-looking helper cells had enough oomph to kill off any B cells Olson and Ludwig made, keeping the pair’s cancers permanently at bay. If so, that could prompt new approaches to selecting cells for CAR-T therapy. Maybe starting with a mix of cell types—not only CD8s, but CD4s and other varieties—would work better than using CD8s alone. Or perhaps inducing changes in cell populations at different times would help.
Another potential avenue for improvement is starting with healthier cells. Evidence from this and other trials hints that patients whose T cells are more robust to begin with respond better when their cells are used in CAR-T therapy. The Penn team recently completed a clinical trial in which CLL patients were treated with ibrutinib—a drug that enhances T-cell function—before their CAR-T cells were manufactured. The response rate, says David Porter, was “very high,” with most patients remaining cancer-free a year after being infused with the souped-up cells.
Such approaches, he adds, are essential to achieving the next phase in CAR-T therapy: “Getting it to work not just in more people, but in everybody.”
Doug Olson enjoys nature - and having a future.
Penn Medicine
To grasp what that could mean, it helps to talk with Doug Olson, who’s now 75. In the years since his infusion, he has watched his four children forge careers, and his grandkids reach their teens. He has built a business and enjoyed the rewards of semi-retirement. He’s done volunteer and advocacy work for cancer patients, run half-marathons, sailed the Caribbean, and ridden his bike along the sun-dappled roads of Silicon Valley, his current home.
And in his spare moments, he has just sat there feeling grateful. “You don’t really appreciate the effect of having a lethal disease until it’s not there anymore,” he says. “The world looks different when you have a future.”