What’s the Right Way to Regulate Gene-Edited Crops?
In the next few decades, humanity faces its biggest food crisis since the invention of the plow. The planet's population, currently 7.6 billion, is expected to reach 10 billion by 2050; to avoid mass famine, according to the World Resource Institute, we'll need to produce 70 percent more calories than we do today.
Imagine that a cheap, easy-to-use, and rapidly deployable technology could make crops more fertile and strengthen their resistance to threats.
Meanwhile, climate change will bring intensifying assaults by heat, drought, storms, pests, and weeds, depressing farm yields around the globe. Epidemics of plant disease—already laying waste to wheat, citrus, bananas, coffee, and cacao in many regions—will spread ever further through the vectors of modern trade and transportation.
So here's a thought experiment: Imagine that a cheap, easy-to-use, and rapidly deployable technology could make crops more fertile and strengthen their resistance to these looming threats. Imagine that it could also render them more nutritious and tastier, with longer shelf lives and less vulnerability to damage in shipping—adding enhancements to human health and enjoyment, as well as reduced food waste, to the possible benefits.
Finally, imagine that crops bred with the aid of this tool might carry dangers. Some could contain unsuspected allergens or toxins. Others might disrupt ecosystems, affecting the behavior or very survival of other species, or infecting wild relatives with their altered DNA.
Now ask yourself: If such a technology existed, should policymakers encourage its adoption, or ban it due to the risks? And if you chose the former alternative, how should crops developed by this method be regulated?
In fact, this technology does exist, though its use remains mostly experimental. It's called gene editing, and in the past five years it has emerged as a potentially revolutionary force in many areas—among them, treating cancer and genetic disorders; growing transplantable human organs in pigs; controlling malaria-spreading mosquitoes; and, yes, transforming agriculture. Several versions are currently available, the newest and nimblest of which goes by the acronym CRISPR.
Gene editing is far simpler and more efficient than older methods used to produce genetically modified organisms (GMOs). Unlike those methods, moreover, it can be used in ways that leave no foreign genes in the target organism—an advantage that proponents argue should comfort anyone leery of consuming so-called "Frankenfoods." But debate persists over what precautions must be taken before these crops come to market.
Recently, two of the world's most powerful regulatory bodies offered very different answers to that question. The United States Department of Agriculture (USDA) declared in March 2018 that it "does not currently regulate, or have any plans to regulate" plants that are developed through most existing methods of gene editing. The Court of Justice of the European Union (ECJ), by contrast, ruled in July that such crops should be governed by the same stringent regulations as conventional GMOs.
Some experts suggest that the broadly permissive American approach and the broadly restrictive EU policy are equally flawed.
Each announcement drew protests, for opposite reasons. Anti-GMO activists assailed the USDA's statement, arguing that all gene-edited crops should be tested and approved before marketing. "You don't know what those mutations or rearrangements might do in a plant," warned Michael Hansen, a senior scientist with the advocacy group Consumers Union. Biotech boosters griped that the ECJ's decision would stifle innovation and investment. "By any sensible standard, this judgment is illogical and absurd," wrote the British newspaper The Observer.
Yet some experts suggest that the broadly permissive American approach and the broadly restrictive EU policy are equally flawed. "What's behind these regulatory decisions is not science," says Jennifer Kuzma, co-director of the Genetic Engineering and Society Center at North Carolina State University, a former advisor to the World Economic Forum, who has researched and written extensively on governance issues in biotechnology. "It's politics, economics, and culture."
The U.S. Welcomes Gene-Edited Food
Humans have been modifying the genomes of plants and animals for 10,000 years, using selective breeding—a hit-or-miss method that can take decades or more to deliver rewards. In the mid-20th century, we learned to speed up the process by exposing organisms to radiation or mutagenic chemicals. But it wasn't until the 1980s that scientists began modifying plants by altering specific stretches of their DNA.
Today, about 90 percent of the corn, cotton and soybeans planted in the U.S. are GMOs; such crops cover nearly 4 million square miles (10 million square kilometers) of land in 29 countries. Most of these plants are transgenic, meaning they contain genes from an unrelated species—often as biologically alien as a virus or a fish. Their modifications are designed primarily to boost profit margins for mechanized agribusiness: allowing crops to withstand herbicides so that weeds can be controlled by mass spraying, for example, or to produce their own pesticides to lessen the need for chemical inputs.
In the early days, the majority of GM crops were created by extracting the gene for a desired trait from a donor organism, multiplying it, and attaching it to other snippets of DNA—usually from a microbe called an agrobacterium—that could help it infiltrate the cells of the target plant. Biotechnologists injected these particles into the target, hoping at least one would land in a place where it would perform its intended function; if not, they kept trying. The process was quicker than conventional breeding, but still complex, scattershot, and costly.
Because agrobacteria can cause plant tumors, Kuzma explains, policymakers in the U.S. decided to regulate GMO crops under an existing law, the Plant Pest Act of 1957, which addressed dangers like imported trees infested with invasive bugs. Every GMO containing the DNA of agrobacterium or another plant pest had to be tested to see whether it behaved like a pest, and undergo a lengthy approval process. By 2010, however, new methods had been developed for creating GMOs without agrobacteria; such plants could typically be marketed without pre-approval.
Soon after that, the first gene-edited crops began appearing. If old-school genetic engineering was a shotgun, techniques like TALEN and CRISPR were a scalpel—or the search-and-replace function on a computer program. With CRISPR/Cas9, for example, an enzyme that bacteria use to recognize and chop up hostile viruses is reprogrammed to find and snip out a desired bit of a plant or other organism's DNA. The enzyme can also be used to insert a substitute gene. If a DNA sequence is simply removed, or the new gene comes from a similar species, the changes in the target plant's genotype and phenotype (its general characteristics) may be no different from those that could be produced through selective breeding. If a foreign gene is added, the plant becomes a transgenic GMO.
Companies are already teeing up gene-edited products for the U.S. market, like a cooking oil and waxy corn.
This development, along with the emergence of non-agrobacterium GMOs, eventually prompted the USDA to propose a tiered regulatory system for all genetically engineered crops, beginning with an initial screening for potentially hazardous metaboloids or ecological impacts. (The screening was intended, in part, to guard against the "off-target effects"—stray mutations—that occasionally appear in gene-edited organisms.) If no red flags appeared, the crop would be approved; otherwise, it would be subject to further review, and possible regulation.
The plan was unveiled in January 2017, during the last week of the Obama presidency. Then, under the Trump administration, it was shelved. Although the USDA continues to promise a new set of regulations, the only hint of what they might contain has been Secretary of Agriculture Sonny Perdue's statement last March that gene-edited plants would remain unregulated if they "could otherwise have been developed through traditional breeding techniques, as long as they are not plant pests or developed using plant pests."
Because transgenic plants could not be "developed through traditional breeding techniques," this statement could be taken to mean that gene editing in which foreign DNA is introduced might actually be regulated. But because the USDA regulates conventional transgenic GMOs only if they trigger the plant-pest stipulation, experts assume gene-edited crops will face similarly limited oversight.
Meanwhile, companies are already teeing up gene-edited products for the U.S. market. An herbicide-resistant oilseed rape, developed using a proprietary technique, has been available since 2016. A cooking oil made from TALEN-tweaked soybeans, designed to have a healthier fatty-acid profile, is slated for release within the next few months. A CRISPR-edited "waxy" corn, designed with a starch profile ideal for processed foods, should be ready by 2021.
In all likelihood, none of these products will have to be tested for safety.
In the E.U., Stricter Rules Apply
Now let's look at the European Union. Since the late 1990s, explains Gregory Jaffe, director of the Project on Biotechnology at the Center for Science in the Public Interest, the EU has had a "process-based trigger" for genetically engineered products: "If you use recombinant DNA, you are going to be regulated." All foods and animal feeds must be approved and labeled if they consist of or contain more than 0.9 percent GM ingredients. (In the U.S., "disclosure" of GM ingredients is mandatory, if someone asks, but labeling is not required.) The only GM crop that can be commercially grown in EU member nations is a type of insect-resistant corn, though some countries allow imports.
European scientists helped develop gene editing, and they—along with the continent's biotech entrepreneurs—have been busy developing applications for crops. But European farmers seem more divided over the technology than their American counterparts. The main French agricultural trades union, for example, supports research into non-transgenic gene editing and its exemption from GMO regulation. But it was the country's small-farmers' union, the Confédération Paysanne, along with several allied groups, that in 2015 submitted a complaint to the ECJ, asking that all plants produced via mutagenesis—including gene-editing—be regulated as GMOs.
At this point, it should be mentioned that in the past 30 years, large population studies have found no sign that consuming GM foods is harmful to human health. GMO critics can, however, point to evidence that herbicide-resistant crops have encouraged overuse of herbicides, giving rise to poison-proof "superweeds," polluting the environment with suspected carcinogens, and inadvertently killing beneficial plants. Those allegations were key to the French plaintiffs' argument that gene-edited crops might similarly do unexpected harm. (Disclosure: Leapsmag's parent company, Bayer, recently acquired Monsanto, a maker of herbicides and herbicide-resistant seeds. Also, Leaps by Bayer, an innovation initiative of Bayer and Leapsmag's direct founder, has funded a biotech startup called JoynBio that aims to reduce the amount of nitrogen fertilizer required to grow crops.)
The ruling was "scientifically nonsensical. It's because of things like this that I'll never go back to Europe."
In the end, the EU court found in the Confédération's favor on gene editing—though the court maintained the regulatory exemption for mutagenesis induced by chemicals or radiation, citing the 'long safety record' of those methods.
The ruling was "scientifically nonsensical," fumes Rodolphe Barrangou, a French food scientist who pioneered CRISPR while working for DuPont in Wisconsin and is now a professor at NC State. "It's because of things like this that I'll never go back to Europe."
Nonetheless, the decision was consistent with longstanding EU policy on crops made with recombinant DNA. Given the difficulty and expense of getting such products through the continent's regulatory system, many other European researchers may wind up following Barrangou to America.
Getting to the Root of the Cultural Divide
What explains the divergence between the American and European approaches to GMOs—and, by extension, gene-edited crops? In part, Jennifer Kuzma speculates, it's that Europeans have a different attitude toward eating. "They're generally more tied to where their food comes from, where it's produced," she notes. They may also share a mistrust of government assurances on food safety, borne of the region's Mad Cow scandals of the 1980s and '90s. In Catholic countries, consumers may have misgivings about tinkering with the machinery of life.
But the principal factor, Kuzma argues, is that European and American agriculture are structured differently. "GM's benefits have mostly been designed for large-scale industrial farming and commodity crops," she says. That kind of farming is dominant in the U.S., but not in Europe, leading to a different balance of political power. In the EU, there was less pressure on decisionmakers to approve GMOs or exempt gene-edited crops from regulation—and more pressure to adopt a GM-resistant stance.
Such dynamics may be operating in other regions as well. In China, for example, the government has long encouraged research in GMOs; a state-owned company recently acquired Syngenta, a Swiss-based multinational corporation that is a leading developer of GM and gene-edited crops. GM animal feed and cooking oil can be freely imported. Yet commercial cultivation of most GM plants remains forbidden, out of deference to popular suspicions of genetically altered food. "As a new item, society has debates and doubts on GMO techniques, which is normal," President Xi Jinping remarked in 2014. "We must be bold in studying it, [but] be cautious promoting it."
The proper balance between boldness and caution is still being worked out all over the world. Europe's process-based approach may prevent researchers from developing crops that, with a single DNA snip, could rescue millions from starvation. EU regulations will also make it harder for small entrepreneurs to challenge Big Ag with a technology that, as Barrangou puts it, "can be used affordably, quickly, scalably, by anyone, without even a graduate degree in genetics." America's product-based approach, conversely, may let crops with hidden genetic dangers escape detection. And by refusing to investigate such risks, regulators may wind up exacerbating consumers' doubts about GM and gene-edited products, rather than allaying them.
"Science...can't tell you what to regulate. That's a values-based decision."
Perhaps the solution lies in combining both approaches, and adding some flexibility and nuance to the mix. "I don't believe in regulation by the product or the process," says CSPI's Jaffe. "I think you need both." Deleting a DNA base pair to silence a gene, for example, might be less risky than inserting a foreign gene into a plant—unless the deletion enables the production of an allergen, and the transgene comes from spinach.
Kuzma calls for the creation of "cooperative governance networks" to oversee crop genome editing, similar to bodies that already help develop and enforce industry standards in fisheries, electronics, industrial cleaning products, and (not incidentally) organic agriculture. Such a network could include farmers, scientists, advocacy groups, private companies, and governmental agencies. "Safety isn't an all-or-nothing concept," Kuzma says. "Science can tell you what some of the issues are in terms of risk and benefit, but it can't tell you what to regulate. That's a values-based decision."
By drawing together a wide range of stakeholders to make such decisions, she adds, "we're more likely to anticipate future consequences, and to develop a robust approach—one that not only seems more legitimate to people, but is actually just plain old better."
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.”