Study Shows “Living Drug” Can Provide a Lasting Cure for Cancer
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.”
This article was first published on Leaps.org on March 24, 2022.
Why You Can’t Blame Your Behavior On Your Gut Microbiome
See a hot pizza sitting on a table. Count the missing pieces: three. They tasted delicious and yes, you've eaten enough—but you're still eyeing a fourth piece. Do you reach out and take it, or not?
"The difficulty comes in translating the animal data into the human situation."
Your behavior in that next moment is anything but simple: as far as scientists can tell, it comes down to a complex confluence of circumstances, genes, and personality characteristics. And the latest proposed addition to this list is the gut microbiome—the community of microorganisms, including bacteria, archaea, fungi, and viruses—that are full-time residents of your digestive tract.
It is entirely plausible that your gut microbiome might influence your behavior, scientists say: a well-known communication channel, called the gut-brain axis, runs both ways between your brain and your digestive tract. Gut bugs, which are close to the action, could amplify or dampen the messages, thereby shaping how you act. Messages about food-related behaviors could be particularly susceptible to interception by these microorganisms.
Perhaps it's convenient to imagine your resident microbes sitting greedily in your gut, crying for more pizza and tricking your brain into getting them what they want. The problem is, there's a distinct lack of scientific support for this actually happening in humans.
John Bienenstock, professor of pathology and molecular medicine at McMaster University (Canada), has worked on the gut microbiome-behavior connection for several decades. "There's a lot of evidence now in animals—particularly in mice," he says.
Indeed, his group and others have shown that, by eliminating or altering gut bugs, they can make mice exhibit different social behaviors or respond more coolly to stress; they can even make a shy mouse turn brave. But Bienenstock cautions: "The difficulty comes in translating the animal data into the human situation."
Animal behaviors are worlds apart from what we do on a daily basis—from brushing our teeth to navigating complex social situations.
Not that it's an easy task to figure out which aspects of animal research are relevant to people in everyday life. Animal behaviors are worlds apart from what we do on a daily basis—from brushing our teeth to navigating complex social situations.
Elaine Hsiao, assistant professor of integrative biology and physiology at UCLA, has also looked closely at the microbiome-gut-brain axis in mice and pondered how to translate the results into humans. She says, "Both the microbiome and behavior vary substantially [from person to person] and can be strongly influenced by environmental factors—which makes it difficult to run a well-controlled study on effects of the microbiome on human behavior."
She adds, "Human behaviors are very complex and the metrics used to quantify behavior are often not precise enough to derive clear interpretations." So the challenge is not only to figure out what people actually do, but also to give those actions numerical codes that allow them to be compared against other actions.
Hsiao and colleagues are nevertheless attempting to make connections: building on some animal research, their recent study found a three-way association in humans between molecules produced by their gut bacteria (that is, indole metabolites), the connectedness of different brain regions as measured through functional magnetic resonance imaging, and measures of behavior: questionnaires assessing food addiction and anxiety.
Meanwhile, other studies have found it may be possible to change a person's behavior through either probiotics or gut-localized antibiotics. Several probiotics even show promise for altering behavior in clinical conditions like depression. Yet how these phenomena occur is still unknown and, overall, scientists lack solid evidence on how bugs control behavior.
Bienenstock, however, is one of many continuing to investigate. He says, "Some of these observations are very striking. They're so striking that clearly something's up."
He says that after identifying a behavior-changing bug, or set of bugs, in mice: "The obvious next thing is: How [is it] occurring? Why is it occurring? What are the molecules involved?" Bienenstock favors the approach of nailing down a mechanism in animal models before starting to investigate its relevance to humans.
He explains, "[This preclinical work] should allow us to identify either target molecules or target pathways, which then can be translated."
Bienenstock also acknowledges the 'hype' that appears to surround this particular field of study. Despite the decidedly slow emergence of data linking the microbiome to human behavior, scientific reviews have appeared in brain-related scientific journals—for instance, Trends in Cognitive Sciences; CNS Drugs—with remarkable frequency. Not only this, but popular books and media articles have given the idea wings.
It might be compelling to blame our microbiomes for behaviors we don't prefer or can't explain—like reaching for another slice of pizza. But until the scientific observations yield stronger results, we still lack proof that we're doing what we do—or eating what we eat—exclusively at the behest of our resident microorganisms.
Who’s Responsible If a Scientist’s Work Is Used for Harm?
Are scientists morally responsible for the uses of their work? To some extent, yes. Scientists are responsible for both the uses that they intend with their work and for some of the uses they don't intend. This is because scientists bear the same moral responsibilities that we all bear, and we are all responsible for the ends we intend to help bring about and for some (but not all) of those we don't.
To not think about plausible unintended effects is to be negligent -- and to recognize, but do nothing about, such effects is to be reckless.
It should be obvious that the intended outcomes of our work are within our sphere of moral responsibility. If a scientist intends to help alleviate hunger (by, for example, breeding new drought-resistant crop strains), and they succeed in that goal, they are morally responsible for that success, and we would praise them accordingly. If a scientist intends to produce a new weapon of mass destruction (by, for example, developing a lethal strain of a virus), and they are unfortunately successful, they are morally responsible for that as well, and we would blame them accordingly. Intention matters a great deal, and we are most praised or blamed for what we intend to accomplish with our work.
But we are responsible for more than just the intended outcomes of our choices. We are also responsible for unintended but readily foreseeable uses of our work. This is in part because we are all responsible for thinking not just about what we intend, but also what else might follow from our chosen course of action. In cases where severe and egregious harms are plausible, we should act in ways that strive to prevent such outcomes. To not think about plausible unintended effects is to be negligent -- and to recognize, but do nothing about, such effects is to be reckless. To be negligent or reckless is to be morally irresponsible, and thus blameworthy. Each of us should think beyond what we intend to do, reflecting carefully on what our course of action could entail, and adjusting our choices accordingly.
It is this area, of unintended but readily foreseeable (and plausible) impacts, that often creates the most difficulty for scientists. Many scientists can become so focused on their work (which is often demanding) and so focused on achieving their intended goals, that they fail to stop and think about other possible implications.
Debates over "dual-use" research exemplify these concerns, where harmful potential uses of research might mean the work should not be pursued, or the full publication of results should be curtailed. When researchers perform gain-of-function research, pushing viruses to become more transmissible or more deadly, it is clear how dangerous such work could be in the wrong hands. In these cases, it is not enough to simply claim that such uses were not intended and that it is someone else's job to ensure that the materials remain secure. We know securing infectious materials can be error-prone (recall events at the CDC and the FDA).
In some areas of research, scientists are already worrying about the unintended possible downsides of their work.
Further, securing viral strains does nothing to secure the knowledge that could allow for reproducing the viral strain (particularly when the methodologies and/or genetic sequences are published after the fact, as was the case for H5N1 and horsepox). It is, in fact, the researcher's moral responsibility to be concerned not just about the biosafety controls in their own labs, but also which projects should be pursued (Will the gain in knowledge be worth the possible downsides?) and which results should be published (Will a result make it easier for a malicious actor to deploy a new bioweapon?).
We have not yet had (to my knowledge) a use of gain-of-function research to harm people. If that does happen, those who actually released the virus on the public will be most blameworthy–-intentions do matter. But the scientists who developed the knowledge deployed by the malicious actors may also be held blameworthy, especially if the malicious use was easy to foresee, even if it was not pleasant to think about.
In some areas of research, scientists are already worrying about the unintended possible downsides of their work. Scientists investigating gene drives have thought beyond the immediate desired benefits of their work (e.g. reducing invasive species populations) and considered the possible spread of gene drives to untargeted populations. Modeling the impacts of such possibilities has led some researchers to pull back from particular deployment possibilities. It is precisely such thinking through both the intended and unintended possible outcomes that is needed for responsible work.
The world has gotten too small, too vulnerable for scientists to act as though they are not responsible for the uses of their work, intended or not. They must seek to ensure that, as the recent AAAS Statement on Scientific Freedom and Responsibility demands, their work is done "in the interest of humanity." This requires thinking beyond one's intentions, potentially drawing on the expertise of others, sometimes from other disciplines, to help explore implications. The need for such thinking does not guarantee good outcomes, but it will ensure that we are doing the best we can, and that is what being morally responsible is all about.