Bispecific T cell engagers are emerging as a powerful class of immunotherapy to treat cancer but are sometimes hindered by unwanted outcomes, such as on-target, off-tumor toxicity; cytokine release syndrome; and neurotoxicity. Now, researchers Penn researchers have developed a novel “switchable” bispecific T cell engager that mitigates these negative effects by co-opting a drug already approved by the FDA. (Image: iStock / CIPhotos)
In the ever-evolving battle against cancer, immunotherapy presents a turning point. It began with harnessing the body’s immune system to fight cancer, a concept rooted more than a century ago but only gaining significant momentum in recent years. Pioneering this shift were therapies like CAR T cell therapy, which reprograms a patient’s T cells to attack cancer cells. Within this domain, bispecific T cell engagers, or bispecific antibodies, have emerged as effective treatments for many blood-borne cancers in the clinic and are being evaluated for solid tumor therapy.
These antibodies simultaneously latch onto both a cancer cell and a T cell, effectively bridging the gap between the two. This proximity triggers the T cells to unleash their lethal arsenal, thereby killing the cancer cells. However, bispecific T cell engagers, like many cancer therapies, face hurdles such as cell-specific targeting limitations, known as on-target off-tumor toxicity, which means the tumor is correctly targeted but so are other healthy cells in the body, leading to healthy tissue damage. Moreover, bispecific antibodies may also lead to immune system overactivation, a precursor for cytokine release syndrome (CRS), and neurotoxicity.
Now, researchers led by Michael Mitchell of the University of Pennsylvania have found a way to circumvent many of these deleterious effects by developing a bispecific T cell nanoengager that is equipped with an “off switch.” Their findings are published in Nature Biomedical Engineering.
“We’re excited to show that bispecific antibodies can be tweaked in a way that allows us to tap into their powerful cancer-killing potential without inducing toxicity to healthy tissues,” says Mitchell, associate professor of bioengineering at Penn’s School of Engineering and Applied Science. “This new controllable drug-delivery mechanism, which we call switchable bispecific T cell nanoengagers, or SiTEs, adds this switchable component to the antibody via administering an FDA-approved small-molecule drug, amantadine.”
(From left to right) Breakthrough Prize recipients Drew Weissman, Virginia M-Y Lee, Katalin Karikó, and Carl June at a reception on Feb. 13. (Image: Courtesy of Penn Medicine News)
In popular culture, scientific discovery is often portrayed in “Eureka!” moments of sudden realization: a lightbulb moment, coming sometimes by accident. But in real life—and in Penn Medicine’s rich history as a scientific innovator for more than 250 years—scientific breakthroughs can never truly be distilled down to a single, “ah-ha” moment. They’re the result of years of hard work, perseverance, and determination to keep going, despite repeated, often discouraging, barriers and setbacks.
“Research is [like taking], four, or six, or eight steps back, and then a little stumble forward,” said Drew Weissman, MD, PhD, the Roberts Family Professor of Vaccine Research. “You keep doing that over and over and somehow, rarely, you can get to the top of the step.”
For Weissman and his research partner, Katalin Karikó, PhD, an adjunct professor of Neurosurgery, that persistence—documented in thousands of news stories across the globe—led to the mRNA technology that enabled two lifesaving COVID-19 vaccines, earning the duo numerous accolades, including the highest scientific honor, the 2023 Nobel Prize in Medicine.
Weissman and Karikó were also the 2022 recipients of the Breakthrough Prize in Life Sciences, the world’s largest science awards, popularly known as the “Oscars of Science.” Founded in 2012 by a group of web and tech luminaries including Google co-founder Sergey Brin and Meta CEO Mark Zuckerberg, the Breakthrough Prizes recognize “the world’s top scientists working in the fundamental sciences—the disciplines that ask the biggest questions and find the deepest explanations.” With six total winners, including four from the Perelman School of Medicine (PSOM), Penn stands alongside Harvard and MIT as the institutions whose researchers have been honored with the most Breakthrough Prizes.
Virginia M.–Y. Lee, PhD, the John H. Ware 3rd Professor in Alzheimer’s Research, was awarded the Prize in 2020 for discovering how different forms of misfolded proteins can move from cell to cell and lead to neurodegenerative disease progression. Carl June, MD, the Richard W. Vague Professor in Immunotherapy, is the most recent recipient and will be recognized at a star-studded red-carpet event in April for pioneering the development of CAR T cell therapy, which programs patients’ own immune cells to fight their cancer.
The four PSOM Breakthrough Prize recipients were honored on Tuesday, Feb. 13, 2024, when a new large-scale installation was unveiled in the lobby of the Biomedical Research Building to celebrate each laurate and their life-changing discoveries. During a light-hearted panel discussion, the honorees shared how a clear purpose, dogged determination, and a good sense of humor enabled their momentum forward.
Weissman presented the Department of Bioengineering’s 2022 Herman P. Schwan Distinguished Lecture: “Nucleoside-modified mRNA-LNP therapeutics.” Read more stories featuring Weissman in the BE Blog here.
3d illustration of a damaged and disintegrating cancer cell. (Image: iStock/vitanovski)
The development of any type of second cancer following CAR T cell therapy is a rare occurrence, as found in an analysis of more than 400 patients treated at Penn Medicine, researchers from the Perelman School of Medicine at the University of Pennsylvania reported today in Nature Medicine. The team also described a single case of an incidental T cell lymphoma that did not express the CAR gene and was found in the lymph node of a patient who developed a secondary lung tumor following CAR T cell therapy.
CAR T cell therapy, a personalized form of immunotherapy in which each patient’s T cells are modified to target and kill their cancer cells, was pioneered at Penn. More than 30,000 patients with blood cancers in the United States—many of whom had few, if any, remaining treatment options available—have been treated with CAR T cell therapy since the first such therapy was approved in 2017. Some of the earliest patients treated in clinical trials have gone on to experience long-lasting remissions of a decade or more.
Secondary cancers, including T cell lymphomas, are a known, rare risk of several types of cancer treatment, including chemotherapy, radiation, and stem cell transplant. CAR T cell therapy is currently only approved to treat blood cancers that have relapsed or stopped responding to treatment, so patients who receive CAR T cell therapies have already received multiple other types of treatment and are facing dire prognoses.
In November 2023, the FDA announced an investigation into several reported cases of secondary T cell malignancies, including CAR-positive lymphoma, in patients who previously received CAR T cell therapy products. In January 2024, the FDA began requiring drugmakers to add a safety label warning to CAR T cell products. While the FDA review is still ongoing, it remains unclear whether the secondary T cell malignancies were caused by CAR T cell therapy.
As a leader in CAR T cell therapy, Penn has longstanding, clearly established protocols to monitor each patient both during and after treatment – including follow-up for 15 years after infusion – and participates in national reporting requirements and databases that track outcomes data from all cell therapy and bone marrow transplants.
Marco Ruella, M.D.
“When this case was identified, we did a detailed analysis and concluded the T cell lymphoma was not related to the CAR T cell therapy. As the news of other cases came to light, we knew we should go deeper, to comb through our own data to better understand and help define the risk of any type of secondary cancer in patients who have received CAR T cell products,” said senior author Marco Ruella, MD, an assistant professor of Hematology-Oncology and Scientific Director of the Lymphoma Program. “What we found was very encouraging and reinforces the overall safety profile for this type of personalized cell therapy.”
Breaking the code of the immune system could provide a new fundamental way of understanding, treating, and preventing every type of disease. Penn Medicine is investing in key discoveries about immunity and immune system function, and building infrastructure, to make that bold idea a reality.
This grandfather lives with primary progressive multiple sclerosis (MS), an autoimmune disorder that he controls with a medicine that depletes his body of the type of immune cells that make antibodies. So while he has completed his COVID-19 vaccine course, his immune system function isn’t very strong—and the invitation has arrived at a time when COVID-19 is still spreading rapidly.
You can imagine the scene as an older gentleman lifts a thick, creamy envelope from his mailbox, seeing his own name written in richly scripted lettering. He beams with pride and gratitude at the sight of his granddaughter’s wedding invitation. Yet his next thought is a sober and serious one. Would he be taking his life in his hands by attending the ceremony?
“In the past, all we could do was [measure] the antibody response,” says Amit Bar-Or, the Melissa and Paul Anderson President’s Distinguished Professor in Neurology at the Perelman School of Medicine, and chief of the Multiple Sclerosis division. “If that person didn’t have a good antibody response, which is likely because of the treatment they’re on, we’d shrug our shoulders and say, ‘Maybe you shouldn’t go because we don’t know if you’re protected.’”
Today, though, Bar-Or can take a deeper dive into his patients’ individual immune systems to give them far more nuanced recommendations. A clinical test for immune cells produced in response to the COVID-19 vaccine or to the SARS-CoV-2 virus itself—not just antibodies—was one of the first applied clinical initiatives of a major new Immune Health® project at Penn Medicine. Doctors were able to order this test and receive actionable answers through the Penn Medicine electronic health record for patients like the grandfather with MS.
“With a simple test and an algorithm we can have a very different discussion,” Bar-Or says. A test result showing low T cells, for instance, would tell Bar-Or his patient may get a meaningful jolt in immunity from a vaccine booster, while low antibody levels would suggest passive antibody therapy is more helpful. Or, the test might show his body is already well primed to protect him, making it reasonably safe to attend the wedding.
This COVID-19 immunity test is only the beginning.
Physicians and scientists at Penn Medicine are imagining a future where patients can get a precise picture of their immune systems’ activity to guide treatment decisions. They are working to bring the idea of Immune Health to life as a new area of medicine. In labs, in complex data models, and in the clinic, they are beginning to make sense out of the depth and breadth of the immune system’s millions of as-yet-undeciphered signals to improve health and treat illnesses of all types.
Penn Medicine registered the trademark for the term “Immune Health” in recognition of the potential impact of this research area and its likelihood to draw non-academic partners as collaborators in its growth. Today, at the south end of Penn’s medical campus, seven stories of research space are being added atop an office building at 3600 Civic Center Blvd., including three floors dedicated to Immune Health, autoimmunity, and immunology research.
The concept behind the whole project, says E. John Wherry, director of Penn Medicine’s Institute for Immunology and Immune Health (I3H), “is to listen to the immune system, to profile the immune system, and use those individual patient immune fingerprints to diagnose and treat diseases as diverse as immune-related diseases, cancer, cardiovascular disease, Alzheimer’s, and many others.”
The challenge is vast. Each person’s immune system is far more complex than antibodies and T cells alone. The immune system is made of multiple interwoven layers of complex defenders—from our skin and mucous membranes to microscopic memory B cells that never forget a childhood infection—meant to fortify our bodies from germs and disease. It is a sophisticated system that learns and adapts over our lifetimes in numerous ways, and it also falters and fails in some ways we understand and others that remain mysterious. And each person’s intricate internal battlefield is in some way unique.
The immune system is not just a set of defensive barricades, either. It’s also a potential source of deep insight about a person’s physiological functioning and responses to medical treatments.
“The immune system is sensing and keeping track of basically all tissues and all cells in our body all the time,” Wherry says. “It is surveying the body trying to clean up any invaders and restore homeostasis by maintaining good health.”
“Our goal is to essentially break the code of the immune system,” says Jonathan Epstein, executive vice dean of the Perelman School of Medicine and chief scientific officer at Penn Medicine. “By doing so, we believe we will be able to determine your state of health and your response to therapies in essentially every human disease.”
On September 14, Wexford Science & Technology, LLC and the University of Pennsylvania announced that the University has signed a lease for new laboratory space that will usher in a wave of novel vaccine, therapeutics, and engineered diagnostics research to West Philadelphia. Research teams from Penn are poised to move into 115,000 square feet of space at One uCity Square, the 13-story, 400,000 square foot purpose-built lab and office building within the vibrant uCity Square Knowledge Community being developed by Wexford. This is the largest lease in the building, encompassing four floors, and bringing the building to over 90% leased. The building currently includes industry tenants Century Therapeutics (NASDAQ: IPSC), Integral Molecular, Exponent (NASDAQ: EXPO), and Charles River Laboratories (NYSE: CRL).
The new University space will house Penn Medicine’s Institute for RNA Innovation and Penn Engineering’s Center for Precision Engineering for Health, underscoring the University’s commitment to a multi-disciplinary and collaborative approach to research that will attract and retain the best talent and engage partners from across the region. Penn’s decision to locate at One uCity Square reinforces uCity Square’s evolution as a central cluster of academic, clinical, commercial, entrepreneurial, and amenity spaces for the area’s innovation ecosystem, and further cements Philadelphia’s position as a top life sciences market.
Jonathan Epstein, MD, Executive Vice Dean and Chief Scientific Officer of Penn Medicine, shared his anticipation for the opportunities that lie ahead: “Penn Medicine is proud to build on its existing clinical presence in uCity Square and establish an innovative and collaborative research presence at the heart of uCity Square’s multidisciplinary innovation ecosystem. This strategic move underscores our commitment to accelerating advancements in biomedical research, industry collaboration, and equipping our talented teams with the resources they need to shape the future of healthcare.”
Locating the Penn Institute for RNA Innovation in the heart of the uCity Square community brings together researchers across disciplines who are already pursuing new vaccines and treatments, and better ways to deliver them. Their shared work will help to power the next phase of vaccine discovery and development.
Likewise, anchoring the work of Penn Engineering’s Center in the One uCity Square space will allow the School’s multi-disciplinary researchers and their collaborators to advance new clinical and diagnostic methods that will focus on intelligent therapeutics, genome design, diagnostics for discovery of human biology, and engineering the human immune shield.
“Penn Engineering has made a substantial commitment to precision engineering for health, an area that is not only important and relevant to engineering, but also critical to the future of humanity,” said Vijay Kumar, Nemirovsky Family Dean of Penn Engineering. “The space in One uCity Square will add another 30,000 square feet of space for our engineers to develop technologies that will fight future pandemics, cure incurable diseases, and extend healthy life spans around the world.”
Spearheading the Penn Institute for RNA Innovation will be Drew Weissman, MD, PhD, the Roberts Family Professor for Vaccine Research, who along with Katalin Karikó, PhD, adjunct professor of Neurosurgery, discovered foundational mRNA technology that enabled the creation of vital vaccine technology, including the FDA-approved mRNA-based COVID-19 vaccines developed by Pfizer-BioNTech and Moderna.
In this new space at One uCity Square, Weissman and his research team and collaborators will further pursue their groundbreaking research efforts with a goal to develop new therapeutics and vaccines and initiate clinical trials for other devastating diseases.
In addition, two established researchers will join the Institute at One uCity Square: Harvey Friedman, MD, a professor of Infectious Diseases, who leads a team researching various vaccines. He will be joined by Vladimir Muzykantov, MD, PhD, Founders Professor in Nanoparticle Research, who focuses on several projects related to targeting the delivery of drugs, including mRNA, to create more effective, targeted pathways to deliver drugs to the vascular system, treating a wide range of diseases that impact the brain, lung, heart, and blood.
Dan Hammer, Alfred G. and Meta A. Ennis Professor in the Departments of Bioengineering and Chemical and Biomolecular Engineering in Penn Engineering and Director of the Center for Precision Engineering for Health, will oversee the Center’s innovations in diagnostics and delivery, cellular and tissue engineering, and the development of new devices that integrate novel materials with human tissues. The Center will bring together scholars from all departments within Penn Engineering and will help to foster increased collaboration with campus colleagues at Penn’s Perelman School of Medicine and with industry partners.
Joining the Center researchers in One uCity Square are Noor Momin, Sherry Gao, and Michael Mitchell. Noor Momin, who will join Penn Engineering in early 2024 as an assistant professor in Bioengineering, will leverage her lab’s expertise in cardiovascular immunology, protein engineering and pharmacokinetic modeling to develop next-generation treatments and diagnostics for cardiovascular diseases.
CAR T cell therapy pioneer Carl June, the Richard W. Vague Professor in Immunotherapy in the Perelman School of Medicine and director of the Center for Cellular Immunotherapies (CCI) at Penn Medicine’s Abramson Cancer Center, has been named a winner of the 2024 Breakthrough Prize in Life Sciences for the development of chimeric antigen receptor (CAR) T cell immunotherapy, a revolutionary cancer treatment approach in which each patient’s T cells are modified to target and kill their cancer cells. The invention sparked a new path in cancer care, harnessing the power of patients’ own immune systems, a once-elusive goal that brought fresh options for those who could not be successfully treated with conventional approaches.
Founded in 2012, the Breakthrough Prizes are the world’s largest science awards, with $3 million awarded for each of the five main prize categories. June is the sixth Breakthrough Prize laureate from Penn, which joins Harvard and MIT among the institutions whose researchers have been honored with the most Breakthrough Prizes.
“This award is not only a testament to Dr. June’s outstanding contributions to science, but also a shining example of the caliber of discoveries and research which Penn faculty set their sights upon,” said Penn President Liz Magill. “We are immensely proud to have Dr. June as a member of the Penn academic community, and we know that CAR T cell therapy is just the first chapter in an inspiring and lifesaving new era of medicine.”
June is internationally recognized for his role in pioneering the CAR T cell therapy, which led to the first FDA-approved personalized cellular therapy, for children and young adults with the blood cancer known as acute lymphoblastic leukemia, in August of 2017—a step which has spurred five additional approvals of the technique in other blood cancers. June joined Penn in 1999, building momentum for Penn to become a global hub for cell and gene therapy. Gene-modified T cells engineered in June’s lab to retrain a patient’s own immune cells to attack cancer were used in the first clinical trial of CAR T cell therapy in 2010. Some of the earliest children and adults treated have experienced long-lasting remissions of 10 years or more. In addition to the FDA approvals that have made the therapy commercially available to patients across the world, thousands more have benefited from clinical trials testing these transformative treatments, including for the treatment of solid tumors and even autoimmune diseases like lupus.
“Dr. June’s tireless commitment to advancing T cell immunotherapy research has been life-changing for many patients affected by cancer, who have lived longer, fuller lives, thanks to the discoveries made in his lab,” said J. Larry Jameson,executive vice president of the University of Pennsylvania for the Health System and dean of the Perelman School of Medicine. “We are proud to see one of Penn’s most esteemed scientists recognized for the impact of his foundational work to develop a new class of cancer immunotherapy treatment.”
Carl June, at the flash mob celebration of the FDA approval of the CAR T cell therapy he developed, in August 2017. (Image: Courtesy of Penn Medicine Magazine)
For most of modern medicine, cancer drugs have been developed the same way: by designing molecules to treat diseased cells. With the advent of immunotherapy, that changed. For the first time, scientists engineered patients’ own immune systems to recognize and attack diseased cells.
One of the best examples of this pioneering type of medicine is CAR T cell therapy. Invented in the Perelman School of Medicine by Carl June, the Richard W. Vague Professor in Immunotherapy, CAR T cell therapy works by collecting T cells from a patient, modifying those cells in the lab so that they are designed to destroy cancerous cells, and reinfusing them into the patient. June’s research led to the first FDA approval for this type of therapy, in 2017. Six different CAR T cell therapies are now approved to treat various types of blood cancers. Carl June, at the flash mob celebration of the FDA approval of the CAR T cell therapy he developed, in August 2017. (Image: Courtesy of Penn Medicine Magazine)
CAR T cell therapy holds the potential to help millions more patients—if it can be successfully translated to other conditions. June and colleagues, including Daniel Baker, a fourth-year doctoral student in the Cell and Molecular Biology department, discuss this potential in a perspective published in Nature.
In the piece, June and Baker highlight other diseases that CAR T cell therapy could be effective.
“CAR T cell therapy has been remarkably successful for blood cancers like leukemias and lymphomas. There’s a lot of work happening here at Penn and elsewhere to push it to other blood cancers and to earlier stage disease, so patients don’t have to go through chemo first,” June says. “Another big priority is patients with solid tumors because they make up the vast majority of cancer patients. Beyond cancer, we’re seeing early signs that CAR T cell therapy could work in autoimmune diseases, like lupus.”
As for which diseases to pursue as for possible future treatment, June says, “essentially it boils down to two questions: Can we identify a population of cells that are bad? And can we target them specifically? Whether that’s asthma or chronic diseases or lupus, if you can find a bad population of cells and get rid of them, then CAR T cells could be therapeutic in that context.”
“What’s exciting is it’s not just theoretical at this point. There have been clinical reports in other autoimmune diseases, including myasthenia gravis and inflammatory myopathy,” Baker says. “But we are seeing early evidence that CAR T cell therapy will be successful beyond cancer. And it’s really opening the minds of people in the field to think about how else we could use CAR T. For example, there’s some pioneering work at Penn from the Epstein lab for heart failure. The idea is that you could use CAR T cells to get rid of fibrotic tissue after a cardiac injury, and potentially restore the damage following a heart attack.”
Baker adds, “there’s no question that over the last decade, CAR T cell therapy has revolutionized cancer. I’m hoping to play a role in bringing these next generation therapies to patients and make a real impact over the next decade. I think there’s potential for cell therapy to be a new pillar of medicine at large, and not just a new pillar of oncology.”
Rather than being the single disease class many people refer to, “cancer” is a blanket term that covers more than 100 distinct diseases, many of which have little in common aside from originating with rapidly dividing cells. Since different cancers demand different treatments, it follows that any given new therapy emerging from any institution would be likely to be a new cancer treatment.
But why so many in just this five-year period?
The volume of new cancer treatments makes sense, says Abramson Cancer Center (ACC) director Robert Vonderheide, attributing the flurry of new cancer drug approvals to a recent “explosion” in knowledge about cancer biology.
“Much of that knowledge is about the immune system’s ability to attack cancer, which people seriously doubted until about 20 years ago. As soon as we had a clinical validation for this Achilles heel in cancer, the dam burst for ideas about other ways to exploit that vulnerability to come forward,” he says. “The first drug that came out to activate the immune system inspired the rest of the field to find the next drug, and the one after that. We as a field have moved from serendipity and empiricism to science-driven drug design.”
The first CAR T cell therapy approval invigorated Penn faculty interested in finding new ways to harness the immune system to fight cancer.
“An approval like that makes what you’re working on more of a reality,” says Avery Posey, an assistant professor of systems pharmacology and translational therapeutics in the Perelman School of Medicine, whose lab team spends much of its time trying to identify more specific antigens for solid tumors and also studies ways to optimize engineered donor T cells. “It brings a new perspective, showing that your work is more than basic research and can actually become drugs that impact patients’ lives. That’s a real motivator to keep pushing forward.”
Honing new immunotherapies is a priority among Penn researchers, but not every recently approved new cancer treatment or detection tool developed at the institution engages the immune system. Faculty have explored and introduced widely varying approaches to improving the standard of care for cancer patients.
Neil Sheppard, Adjunct Associate Professor of Pathology and Laboratory Medicine in the Perelman School of Medicine, and David Mai, a Bioengineering graduate student in the School of Engineering and Applied Science, explained the findings of their recent study, which offered a potential strategy to improve T cell therapy in solid tumors, to the European biotech news website Labiotech.
Congratulations to two Bioengineering graduate students who were awarded Student Travel Achievement Recognition (STAR) Awards from the Society for Biomaterials (SFB). The STAR Award recognizes research excellence and develops future leaders within SFB and comes with a certificate and a monetary award of $250. Penn Bioengineering graduate students Rebecca Haley and Alex Hamilton, both members of the lab of Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in Bioengineering, received their awards and presented on their research in the SFB annual meeting in April 2023.
Rebecca Haley, Ph.D. student in Bioengineering
Rebecca Haley is a Ph.D. student in Bioengineering and a NSF Graduate Research Fellow. In the Mitchell Lab, she focuses on the use of ionizable lipid nanoparticles for the delivery of protein cargos. Supported by this STAR award, she presented her work delivering small protein RAS-inhibitors that reduce cancer cell proliferation. Rebecca is interested in expanding the applications of lipid nanoparticle technology, allowing currently limited therapeutics to achieve functional delivery and, hopefully, clinical success.
Alex Hamilton, Ph.D. student in Bioengineering
Alex Hamilton is a Ph.D. student in Bioengineering and an NSF Graduate Research Fellow. Alex’s work in the Mitchell lab focuses on non-viral nucleic acid delivery. His research interests include cancer immunotherapy, vaccines, and fetal-maternal medicine. He is currently engaged in using novel high-throughput screening techniques to accelerate the discovery process for lipid nanoparticle development for a variety of disease applications.
Two more Mitchell Lab members were likewise recognized with honorable mention inn the STAR Awards: Hannah Safford, a Ph.D. student in Bioengineering and NSF Fellow, and Rohan Palanki, a M.D.-Ph.D. student in Bioengineering and NIH Fellow
Learn more about the Mitchell Lab’s research in biomaterials science, drug delivery, and cellular and molecular bioengineering in the lab’s website.
Read more stories featuring Mitchell and his team here.
